# US 7,612,788 B2 · Driving multiple sub-pixels from single gray scale data > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,612,788 B2 - Document ID: US7612788B2 - Status: Granted - Kind: B2 - Application number: 11/208,498 - Filed: 2005-08-22 - Published: 2006-07-20 - Granted: 2009-11-03 - Earliest claimed: 2005-01-18 - Assignees: Samsung Electronics Co., Ltd. - Inventors: Il-Kwon Chang; Yong-Weon Jeon - Web page: https://patentgrep.com/patent/US7612788B2 ## CPC - 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 2330/021: Power management, e.g. power saving - G09G 2330/06: Handling electromagnetic interferences [EMI], covering emitted as well as received electromagnetic radiation - 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 For generating source line voltages in a display device, gray scale data is received at a source driver for a first sub-pixel of a pixel. The source driver generates a first source line voltage for the first sub-pixel and a second source line voltage for a second sub-pixel from the gray scale data of the first sub-pixel. Thus, data transfer rate and/or data buses are minimized for in turn minimizing power consumption and EMI (electromagnetic interference). ## Claims ### Claim 1 A method of generating source line voltages in a display device, comprising: receiving by a source driver gray scale data for a first sub-pixel of a pixel having the first sub-pixel and a second sub-pixel; wherein the source driver receives the gray scale data for the first sub-pixel during a one line time period while the source driver does not receive any gray scale information for the second sub-pixel during any portion of the one line time period; generating by the source driver a first source line voltage for the first sub-pixel from the gray scale data during a first portion of said one line time period; and generating by the source driver a second source line voltage for the second sub-pixel of the pixel from the gray scale data of the first sub-pixel during a second portion of said one line time period such that the second source line voltage of the second sub-pixel becomes determined at the source driver during the second portion of said one line time period, wherein said one line time period is for a time length when a polarity signal remains constant during said time length, and wherein the polarity signal alternates between high and low logic states after each of said time length. ### Claim 2 (depends on 1) The method of claim 1, further comprising: generating the first source line voltage from the gray scale data and a first luminance curve; and generating the second source line voltage from the gray scale data of the first sub-pixel and a second luminance curve. ### Claim 3 (depends on 2) The method of claim 2, wherein generating the first source line voltage includes the steps of: selecting, from the first luminance curve, first high and low reference voltages for a D/A (digital to analog) converter depending on at least one most-significant bit of the gray scale data; and digital to analog converting at least one least-significant bit of the gray scale data at the D/A converter with the selected first high and low reference voltages. ### Claim 4 (depends on 3) The method of claim 3, wherein generating the second source line voltage includes the steps of: selecting, from the second luminance curve, second high and low reference voltages for the D/A converter depending on the at least one most-significant bit of the gray scale data; and digital to analog converting the at least one least-significant bit of the gray scale data at the D/A converter with the selected second high and low reference voltages. ### Claim 5 (depends on 3) The method of claim 3, wherein the D/A converter is linear. ### Claim 6 (depends on 2) The method of claim 2, wherein the first and second luminance curves together are for upper gamma reference voltages or for lower gamma reference voltages. ### Claim 7 (depends on 6) The method of claim 6, wherein the first and second luminance curves are for the upper gamma reference voltages when the sub-pixels are driven for a positive polarity, and are for the lower gamma reference voltages when the sub-pixels are driven for a negative polarity. ### Claim 8 (depends on 6) The method of claim 6, wherein the luminance curves for the upper and lower gamma reference voltages are alternately used for generating successive sets of first and second source line voltages. ### Claim 9 (depends on 1) The method of claim 1, further comprising: driving the first sub-pixel with the first source line voltage during said second portion of said one line time period; and driving the second sub-pixel with the second source line voltage during a portion of a subsequent one line time period after said one line time period. ### Claim 10 A source driver of a display device, the source driver comprising: a storage unit for receiving and storing gray scale data for a first sub-pixel of a pixel having the first sub-pixel and a second sub-pixel; wherein the source driver receives the gray scale data for the first sub-pixel during a one line time period while the source driver does not receive any gray scale information for the second sub-pixel during any portion of the one line time period; and a source line voltage generator for generating a first source line voltage for the first sub-pixel from the gray scale data during a first portion of said one line time period, and for generating a second source line voltage for the second sub-pixel of the pixel from the gray scale data of the first sub-pixel during a second portion of said one line time period such that the second source line voltage of the second sub-pixel becomes determined at the source driver during the second portion of said one line time period, wherein said one line time period is for a time length when a polarity signal remains constant during said time length, and wherein the polarity signal alternates between high and low logic states after each of said time length. ### Claim 11 (depends on 10) The source driver of claim 10, wherein the source line voltage generator generates the first source line voltage from the gray scale data and a first luminance curve, and generates the second source line voltage from the gray scale data of the first sub-pixel and a second luminance curve. ### Claim 12 (depends on 11) The source driver of claim 11, wherein the source line voltage generator includes: a D/A (digital to analog) converter; and a reference voltage generator for selecting, from the first and second luminance curve, first high and low reference voltages and second high and low reference voltages for the D/A converter depending on at least one most-significant bit of the gray scale data; wherein the D/A converter converts at least one least-significant bit of the gray scale data with the selected first high and low reference voltages to generate the first source line voltage, and with the selected second high and low reference voltages to generate the second source line voltage. ### Claim 13 (depends on 12) The source driver of claim 12, wherein the reference voltage generator includes: A/B selectors, each selecting a respective set of reference voltages from the luminance curves depending on which of the sub-pixels is to be driven; an upper/lower selector for selecting one respective set of reference voltages from the A/B selectors depending on which polarity is indicated; and a VH,VL selector for selecting high and low reference voltages from the selected respective set of reference voltages depending on select signals generated from the at least one most-significant bit of the gray scale data. ### Claim 14 (depends on 12) The source driver of claim 12, wherein the D/A converter is linear. ### Claim 15 (depends on 12) The source driver of claim 12, wherein the D/A converter is a charge redistribution D/A converter. ### Claim 16 (depends on 11) The source driver of claim 11, wherein the first and second luminance curves together are for upper gamma reference voltages or for lower gamma reference voltages. ### Claim 17 (depends on 16) The source driver of claim 16, wherein the first and second luminance curves are for the upper gamma reference voltages when the sub-pixels are driven for a positive polarity, and are for the lower gamma reference voltages when the sub-pixels are driven for a negative polarity. ### Claim 18 (depends on 16) The source driver of claim 16, wherein the luminance curves for the upper and lower gamma reference voltages are alternately used for generating successive sets of first and second source line voltages. ### Claim 19 (depends on 10) The source driver of claim 10, wherein the first sub-pixel is driven with the first source line voltage during said second portion of said one line time period, and wherein the second sub-pixel is driven with the second source line voltage during a portion of a subsequent one line time period after said one line time period. ### Claim 20 A display device comprising: a display panel having a plurality of gate lines and source lines; gate drivers for generating scan signals of the gate lines; and source drivers for generating source line voltages of the source lines, each source driver comprising: a storage unit for receiving and storing gray scale data for a first sub-pixel of a pixel having the first sub-pixel and a second sub-pixel; wherein the source driver receives the gray scale data for the first sub-pixel during a one line time period while the source driver does not receive any gray scale information for the second sub-pixel during any portion of the one line time period; and a source line voltage generator for generating a first source line voltage for the first sub-pixel from the gray scale data during a first portion of said one line time period, and for generating a second source line voltage for the second sub-pixel of the pixel from the gray scale data of the first sub-pixel during a second portion of said one line time period such that the second source line voltage of the second sub-pixel becomes determined at the source driver during the second portion of said one line time period, wherein said one line time period is for a time length when a polarity signal remains constant during said time length, and wherein the polarity signal alternates between high and low logic states after each of said time length. ### Claim 21 (depends on 20) The display device of claim 20, wherein the source line voltage generator generates the first source line voltage from the gray scale data and a first luminance curve, and generates the second source line voltage from the gray scale data of the first sub-pixel and a second luminance curve. ### Claim 22 (depends on 21) The display device of claim 21, wherein the source line voltage generator includes: a D/A (digital to analog) converter; and a reference voltage generator for selecting, from the first and second luminance curves, first high and low reference voltages and second high and low reference voltages for the D/A converter depending on at least one most-significant bit of the gray scale data; wherein the D/A converter converts at least one least-significant bit of the gray scale data with the selected first high and low reference voltages to generate the first source line voltage, and with the selected second high and low reference voltages to generate the second source line voltage. ### Claim 23 (depends on 22) The display device of claim 22, wherein the reference voltage generator includes: A/B selectors, each selecting a respective set of reference voltages from the luminance curves depending on which of the sub-pixels is to be driven; an upper/lower selector for selecting one respective set of reference voltages from the A/B selectors depending on which polarity is indicated; and a VH,VL selector for selecting high and low reference voltages from the selected respective set of reference voltages depending on select signals generated from the at least one most-significant bit of the gray scale data. ### Claim 24 (depends on 22) The display device of claim 22, wherein the D/A converter is linear. ### Claim 25 (depends on 22) The display device of claim 22, wherein the D/A converter is a charge redistribution D/A converter. ### Claim 26 (depends on 21) The display device of claim 21, wherein the first and second luminance curves together are for one of upper gamma reference voltages or lower gamma reference voltages. ### Claim 27 (depends on 26) The display device of claim 26, wherein the first and second luminance curves are for the upper gamma reference voltages when the sub-pixels are driven for a positive polarity, and are for the lower gamma reference voltages when the sub-pixels are driven for a negative polarity. ### Claim 28 (depends on 26) The display device of claim 26, wherein the luminance curves for the upper and lower gamma reference voltages are alternately used for generating successive sets of first and second source line voltages. ### Claim 29 (depends on 20) The display device of claim 20, wherein the display panel is a liquid crystal display (LCD) panel. ### Claim 30 (depends on 20) The display device of claim 20, wherein the first sub-pixel is driven with the first source line voltage during said second portion of said one line time period, and wherein the second sub-pixel is driven with the second source line voltage during a portion of a subsequent one line time period after said one line time period.