# US 12,002,413 B2 · Display device and dimming driving method thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,002,413 B2 - Document ID: US12002413B2 - Status: Granted - Kind: B2 - Application number: 18/176,910 - Filed: 2023-03-01 - Published: 2023-10-12 - Granted: 2024-06-04 - Earliest claimed: 2022-04-06 - Assignees: Samsung Display Co., Ltd. - Applicants: Samsung Display Co., LTD. - Inventors: Hong Soo Kim; Myung Woo Lee; Suk Hun Lee - Web page: https://patentgrep.com/patent/US12002413B2 ## CPC - G09G 3/32: semiconductive, e.g. using light-emitting diodes [LED] - G09G 3/3233: with pixel circuitry controlling the current through the light-emitting element - G09G 3/2014: {by modulation of the duration of a single pulse during which the logic level remains constant} - G09G 3/2022: {using sub-frames} - G09G 3/2081: {with combination of amplitude modulation and time modulation (space and time error diffusion G09G3/2066)} - G09G 3/3258: with pixel circuitry controlling the voltage across the light-emitting element - G09G 2300/0861: with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes - G09G 2320/0626: for control of overall brightness - G09G 2320/0633: by amplitude modulation of the brightness of the illumination source - 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 device comprises a pixel configured to be driven in cycle periods during a frame period defined by a vertical start signal, and a display driver configured to divide a cycle period into subfields for driving, configured to control an amount of current flowing through the pixel and to control emission on-duties of the subfields, and configured to independently determine, for the cycle period, a reference duty that is a minimum emission on-duty set in the cycle period based on a dimming signal. ## Claims ### Claim 1 A display device comprising: a pixel configured to be driven in cycle periods during a frame period defined by a vertical start signal; and a display driver configured to divide a cycle period into subfields for driving, configured to control an amount of current flowing through the pixel and to control emission on-duties of the subfields, and configured to independently determine, for the cycle period, a reference duty that is a minimum emission on-duty set in the cycle period based on a dimming signal. ### Claim 2 (depends on 1) The display device of claim 1, wherein the pixel comprises an inorganic light emitting element. ### Claim 3 (depends on 1) The display device of claim 1, wherein the cycle period comprises first to eighth subfields having different respective emission on-duties. ### Claim 4 (depends on 3) The display device of claim 3, wherein the frame period comprises first to fourth cycle periods, and wherein the display driver is configured to determine the emission on-duties of the first to eighth subfields of the first cycle period based on a first reference duty, to determine the emission on-duties of the first to eighth subfields of the second cycle period based on a second reference duty, to determine the emission on-duties of the first to eighth subfields of the third cycle period based on a third reference duty, and to determine the emission on-duties of the first to eighth subfields of the fourth cycle period based on a fourth reference duty. ### Claim 5 (depends on 4) The display device of claim 4, wherein a length of one of the first to fourth reference duties is different from a length of another one of the first to fourth reference duties. ### Claim 6 (depends on 4) The display device of claim 4, wherein a length of the first reference duty and a length of the second reference duty are different from each other, and lengths of the emission on-duties of the first to eighth subfields of the first cycle period are different from lengths of the emission on-duties of the first to eighth subfields of the second cycle period, respectively. ### Claim 7 (depends on 4) The display device of claim 4, wherein the display driver comprises: an oscillator configured to output a clock signal having a preset frequency; and an on-duty controller configured to determine clock numbers corresponding to the first to fourth reference duties in response to a dimming level comprised in the dimming signal, and configured to generate PWM signals respectively having the first to fourth reference duties based on counted value of the clock signal. ### Claim 8 (depends on 7) The display device of claim 7, wherein the on-duty controller is configured to generate PWM signals supplied to the first to eighth subfields of the first cycle period based on the PWM signal having the first reference duty, respectively. ### Claim 9 (depends on 8) The display device of claim 8, wherein the PWM signals are configured to be supplied to the pixel as control signals corresponding to emission periods corresponding to the emission on-duties of the pixel. ### Claim 10 (depends on 7) The display device of claim 7, wherein the display driver further comprises: a voltage generator configured to generate a PAM data voltage supplied to the pixel in writing periods of the first to eighth subfields; and a current controller configured to control a magnitude of the PAM data voltage for the first to fourth cycle periods in response to the dimming level. ### Claim 11 (depends on 10) The display device of claim 10, wherein a magnitude of one PAM data voltage supplied to the pixel during the first to fourth cycle periods is different from a magnitude of another PAM data voltages supplied to the pixel during the first to fourth cycle periods. ### Claim 12 (depends on 10) The display device of claim 10, wherein a magnitude of the PAM data voltage supplied to the pixel during the first cycle period is different from a magnitude of the PAM data voltage supplied to the pixel during the fourth cycle period. ### Claim 13 (depends on 12) The display device of claim 12, wherein a current flowing into a light emitting element of the pixel during the first cycle period is different from a current flowing into the light emitting element of the pixel during the fourth cycle period. ### Claim 14 (depends on 4) The display device of claim 4, wherein a total emission period corresponding to a sum of the emission on-duties of the frame period is about 30% or less of the frame period. ### Claim 15 A dimming driving method of a display device comprising: determining a first reference duty and a second reference duty, which are minimum emission on-duties set in a first cycle period and a second cycle period of a frame period, respectively, and which have different respective lengths, in response to a dimming level of a dimming signal; dividing the first cycle period into first to eighth subfields based on the first reference duty to drive; and dividing the second cycle period into first to eighth subfields based on the second reference duty to drive. ### Claim 16 (depends on 15) The method of claim 15, wherein the first to eighth subfields have different respective emission on-duties that correspond to an emission period of a pixel. ### Claim 17 (depends on 16) The method of claim 16, wherein respective lengths of the emission on-duties of the first to eighth subfields of the first cycle period are different from respective lengths of the emission on-duties of the first to eighth subfields of the second cycle period. ### Claim 18 (depends on 17) The method of claim 17, wherein the determining the first reference duty and the second reference duty comprises: determining a clock number of an output of an oscillator corresponding to the first reference duty, and a clock number of an output of the oscillator corresponding to the second reference duty, in response to the dimming level; and generating a PWM signal having the first reference duty and a PWM signal having the second reference duty by counting the clock number. ### Claim 19 (depends on 17) The method of claim 17, further comprising: determining a first PAM data voltage supplied to the pixel in the first cycle period, and a second PAM data voltage having a different magnitude than the first PAM data voltage and supplied to the pixel in the second cycle period, in response to the dimming level; supplying the first PAM data voltage to the pixel in the first cycle period; and supplying the second PAM data voltage to the pixel in the second cycle period. ### Claim 20 (depends on 19) The method of claim 19, wherein the pixel comprises an inorganic light emitting element, and wherein a current flowing through the inorganic light emitting element during an emission period of the first cycle period is different from a current flowing through the inorganic light emitting element during an emission period of the second cycle period.