# US 7,746,305 B2 · Method and apparatus for driving liquid crystal display deriving modulated data using approximation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,746,305 B2 - Document ID: US7746305B2 - Status: Granted - Kind: B2 - Application number: 11/589,171 - Filed: 2006-10-30 - Published: 2007-02-22 - Granted: 2010-06-29 - Earliest claimed: 2001-09-06 - Assignees: LG Display Co., Ltd. - Inventors: Yong Sung Ham - Web page: https://patentgrep.com/patent/US7746305B2 ## CPC - G09G 3/2011: {by amplitude modulation} - G09G 3/3648: {using an active matrix (G09G3/367 - G09G3/3696 take precedence)} - G09G 2320/0252: Improving the response speed - G09G 2320/0261: in the context of movement of objects on the screen or movement of the observer relative to the screen - G09G 2340/16: Determination of a pixel data signal depending on the signal applied in the previous frame - 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 present invention discloses a method and apparatus of driving a liquid crystal display device improving a picture quality. In the method and apparatus, modulated data bands including at least two modulated data centering a gray scale being approximate to a gray scale value of source data are derived. An approximation is carried out in two directions perpendicular to each other within the modulated data bands to derive unregistered modulated data positioned between the modulated data, thereby modulating the source data. ## Claims ### Claim 1 A method of driving a liquid crystal display, comprising: registering a plurality of modulated data in look-up table; a modulated data band including a predetermined number of modulated data from the plurality of modulated data, each gray level value of the predetermined number of modulated data being adjacent to a gray level value of source data in horizontal and vertical directions within the look-up table; carrying out first and second approximations based on the modulated data band to derive an approximate modulated data not registered in the look-up table, thereby modulating the source data using the approximate modulated data. ### Claim 2 (depends on 1) The method according to claim 1, further comprising: dividing the source data into most significant bits and least significant bits; and delaying each of the most significant bits and the least significant bits for a frame period. ### Claim 3 (depends on 2) The method according to claim 2, further comprising, comparing the most significant bits of a current frame with those of the delayed frame within the look-up table to derive the modulated data band in accordance with the compared result. ### Claim 4 (depends on 1) The method according to claim 1, wherein the carrying out first and second approximations includes: carrying out the first approximation using current least significant bits along the horizontal direction within the modulated data band to derive two first approximate values existing on the horizontal direction; and carrying out the second approximation using previous least significant bits on a line between the two first approximate values to derive the approximate modulated data. ### Claim 5 (depends on 1) The method according to claim 1, wherein the carrying out first and second approximations includes: carrying out the first approximation using previous least significant bits along the vertical direction within the modulated data band to derive two first approximate values existing on the vertical direction; and carrying out the second approximation using current least significant bits on a line between the two first approximate values to derive the approximate modulated data. ### Claim 6 A driving apparatus for driving a liquid crystal display, comprising: a look-up table having a plurality of registered modulated data and to derive a modulated data band including a predetermined number of modulated data from the plurality of modulated data, each gray level value of the predetermined number of modulated data being adjacent to a gray level value of source data in horizontal and vertical directions within the look-up table; and a modulator to approximate in the horizontal and vertical directions within the modulated data band to derive an approximate modulated data not registered in the look-up table, to thereby modulate the source data using the approximate modulated data. ### Claim 7 (depends on 6) The driving apparatus according to claim 6, further comprising: a first frame memory for delaying most significant bits of the source data; and a second frame memory for delaying least significant bits of the source data. ### Claim 8 (depends on 7) The driving apparatus according to claim 7, wherein the modulator is to compare delayed most significant bits with non-delayed most significant bits within the look-up table to derive the modulated data band in accordance with the compared result. ### Claim 9 (depends on 6) The driving apparatus according to claim 6, wherein the modulator includes: a first approximation processor to carry out a first approximation using current least significant bits along the horizontal direction within the modulated data band to derive two first approximate values existing on the horizontal direction; and a second approximation processor to carry out a second approximation using previous least significant bits on a line between the two first approximate values to derive the approximate modulated data. ### Claim 10 (depends on 6) The driving apparatus according to claim 6, wherein the modulator includes: a first approximation processor to carry out a first approximation using previous least significant bits along the vertical direction within the modulated data band to derive two first approximate values existing on the vertical direction; and a second approximation processor to carry out a second approximation using current least significant bits on a line between the two first approximate values to derive the approximate modulated data. ### Claim 11 (depends on 6) The driving apparatus according to claim 6, further comprising: a data driver to apply data modulated by using the modulator to the liquid crystal display; a gate driver to apply a scanning signal to the liquid crystal display; and a timing controller to apply the source data to the modulator and to control the data driver and the gate driver. ### Claim 12 (depends on 6) The driving apparatus according to claim 6, further comprising a single frame memory to delay both most significant bit of the source data and least significant bit of the source data. ### Claim 13 (depends on 6) The driving apparatus according to claim 6, wherein the modulator includes a single approximation processor to carry out a first approximation using current least significant bits along the horizontal direction within the modulated data band to derive two first approximate values existing on the horizontal direction, and a second approximation using previous least significant bits on a line between the two first approximate values to derive the approximate modulated data. ### Claim 14 (depends on 6) The driving apparatus according to claim 6, wherein the modulator includes: a first approximation processor to carry out a first approximation using previous least significant bits along the vertical direction within the modulated data band to derive two first approximate values existing on the vertical direction; and a second approximation processor to carry out a second approximation using current least significant bits on a line between the two first approximate values to derive the approximate modulated data. ### Claim 15 A liquid crystal display, comprising: a liquid crystal display panel to display images; a look-up table having a plurality of registered modulated data and to derive a modulated data band including a predetermined number of modulated data from the plurality of modulated data, each gray level value of the predetermined number of modulated data being adjacent to a gray level value of source data in horizontal and vertical directions within the look-up table; and a modulator to approximate in the horizontal and vertical directions within the modulated data band to derive an approximate modulated data not registered in the look-up table, to thereby modulate the source data using the approximated modulated data.