# US 12,112,710 B2 · Display driver and display device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,112,710 B2 - Document ID: US12112710B2 - Status: Granted - Kind: B2 - Application number: 18/451,853 - Filed: 2023-08-18 - Published: 2024-02-29 - Granted: 2024-10-08 - Earliest claimed: 2022-08-31 - Assignees: LAPIS Technology Co., Ltd. - Applicants: LAPIS Technology Co., Ltd. - Inventors: Fumiya Kojima; Young Gi Kim - Web page: https://patentgrep.com/patent/US12112710B2 ## CPC - G09G 3/3275: Details of drivers for data electrodes - G09G 3/20: for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix {no fixed position being assigned to or needed to be assigned to the individual characters or partial characters} - G09G 3/3696: {Generation of voltages supplied to electrode drivers} - G09G 2300/0828: forming a digital to analog [D/A] conversion circuit - G09G 2310/027: Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters - G09G 2310/0291: Details of output amplifiers or buffers arranged for use in a driving circuit - 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 2320/0673: for control of gamma adjustment, e.g. selecting another gamma curve - G09G 2330/021: Power management, e.g. power saving - G09G 2330/028: Generation of voltages supplied to electrode drivers in a matrix display other than LCD - 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 display driver and a display device are provided. The driver includes a first ladder resistor receiving a first potential at one end and a higher second potential at the other end to generate voltages obtained by dividing a voltage between first and second potentials; a second ladder resistor receiving first potential at one end, a second potential at the other end, and each of partial voltages among the voltages generated by the first ladder resistor at a connection point between the resistors to generate gradation reference voltages; first to k-th input amplifiers individually amplifying first to k-th DC bottom potentials respectively corresponding to first to k-th gamma correction characteristics to generate first to k-th amplified bottom potentials; and a first selector sequentially selecting one of the first to k-th amplified bottom potentials and supplying the selected one to one end of the first ladder resistor as a first potential. ## Claims ### Claim 1 A display driver for driving a display panel having a plurality of display cells respectively connected to a plurality of data lines based on a plurality of pixel data pieces representing a luminance level represented by a video signal, comprising: a gradation reference voltage generator which generates a plurality of gradation reference voltages along first to k-th (k is an integer of 2 or more) gamma correction characteristics for different color components; and a DA conversion unit which selects a gradation reference voltage corresponding to a luminance level represented by the pixel data piece from the plurality of gradation reference voltages for each of the plurality of pixel data pieces and outputs the gradation reference voltage as a gradation voltage, wherein the gradation reference voltage generator includes a first ladder resistor which receives a first potential at one end and receives a second potential higher than the first potential at the other end to generate a plurality of voltages obtained by dividing a voltage between the first potential and the second potential, a second ladder resistor which receives the first potential at one end, receives the second potential at the other end, and receives each of a plurality of partial voltages among the plurality of voltages at a connection point between the resistors to generate the plurality of gradation reference voltages, first to k-th input amplifiers which receive first to k-th DC bottom potentials respectively corresponding to the first to k-th gamma correction characteristics, individually amplify the first to k-th DC bottom potentials, and output first to k-th amplified bottom potentials, and a first selector which receives the first to k-th amplified bottom potentials, sequentially selects one amplified bottom potential among the first to k-th amplified bottom potentials, and supplies the one selected amplified bottom potential to the one end of the first ladder resistor as the first potential. ### Claim 2 (depends on 1) The display driver according to claim 1, further comprising: a second selector which receives the first to k-th amplified bottom potentials, sequentially selects one amplified bottom potential from the first to k-th amplified bottom potentials, and supplies the one selected amplified bottom potential to the one end of the second ladder resistor as the first potential. ### Claim 3 (depends on 2) The display driver according to claim 2, further comprising: a switching control unit which controls the first selector and the second selector so that the one amplified bottom potential selected from the first to k-th amplified bottom potentials by the first selector and the second selector is switched to the other amplified bottom potential for each of a plurality of periods obtained by dividing each horizontal scanning period in the video signal. ### Claim 4 (depends on 3) The display driver according to claim 3, wherein the first amplified bottom potential selected from the first to k-th amplified bottom potentials by the second selector is the same as the first amplified bottom potential selected from the first to k-th amplified bottom potentials by the first selector. ### Claim 5 (depends on 4) The display driver according to claim 4, wherein a wiring that supplies the one amplified bottom potential selected by the first selector to one end of the first ladder resistor is electrically separated from a wiring that supplies the one amplified bottom potential selected by the second selector to one end of the second ladder resistor. ### Claim 6 (depends on 3) The display driver according to claim 3, wherein the k is 3, and wherein the first gamma correction characteristic is a gamma correction characteristic for a red component, the second gamma correction characteristic is a gamma correction characteristic for a green component, and the third gamma correction characteristic is a gamma correction characteristic for a blue component. ### Claim 7 (depends on 2) The display driver according to claim 2, wherein the first amplified bottom potential selected from the first to k-th amplified bottom potentials by the second selector is the same as the first amplified bottom potential selected from the first to k-th amplified bottom potentials by the first selector. ### Claim 8 (depends on 7) The display driver according to claim 7, wherein a wiring that supplies the one amplified bottom potential selected by the first selector to one end of the first ladder resistor is electrically separated from a wiring that supplies the one amplified bottom potential selected by the second selector to one end of the second ladder resistor. ### Claim 9 (depends on 2) The display driver according to claim 2, wherein the k is 3, and wherein the first gamma correction characteristic is a gamma correction characteristic for a red component, the second gamma correction characteristic is a gamma correction characteristic for a green component, and the third gamma correction characteristic is a gamma correction characteristic for a blue component. ### Claim 10 (depends on 1) The display driver according to claim 1, wherein the k is 3, and wherein the first gamma correction characteristic is a gamma correction characteristic for a red component, the second gamma correction characteristic is a gamma correction characteristic for a green component, and the third gamma correction characteristic is a gamma correction characteristic for a blue component. ### Claim 11 A display device comprising: a display panel in which a plurality of display cells are respectively connected to a plurality of data lines; and a display driver which drives the display panel based on a plurality of pixel data pieces representing a luminance level represented by a video signal, wherein the display driver includes a gradation reference voltage generator which generates a plurality of gradation reference voltages along first to k-th (k is an integer of 2 or more) gamma correction characteristics for different color components and a DA conversion unit which selects a gradation reference voltage corresponding to a luminance level represented by the pixel data piece from the plurality of gradation reference voltages for each of the plurality of pixel data pieces and outputs the gradation reference voltage as a gradation voltage, and wherein the gradation reference voltage generator includes a first ladder resistor which receives a first potential at one end and receives a second potential higher than the first potential at the other end to generate a plurality of voltages obtained by dividing a voltage between the first potential and the second potential, a second ladder resistor which receives the first potential at one end, receives the second potential at the other end, and receives each of a plurality of partial voltages among the plurality of voltages at a connection point between the resistors to generate the plurality of gradation reference voltages, first to k-th input amplifiers which receive first to k-th DC bottom potentials respectively corresponding to the first to k-th gamma correction characteristics, individually amplify the first to k-th DC bottom potentials, and output first to k-th amplified bottom potentials, and a first selector which receives the first to k-th amplified bottom potentials, sequentially selects one amplified bottom potential among the first to k-th amplified bottom potentials, and supplies the one selected amplified bottom potential to the one end of the first ladder resistor as the first potential.