# US 12,183,292 B2 · Backlight driving method and display panel > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,183,292 B2 - Document ID: US12183292B2 - Status: Granted - Kind: B2 - Application number: 17/289,291 - Filed: 2021-04-25 - Published: 2024-04-18 - Granted: 2024-12-31 - Earliest claimed: 2021-04-12 - Assignees: Tcl China Star Optoelectronics Technology Co., Ltd. - Applicants: TCL China Star Optoelectronics Technology Co., Ltd. - Inventors: Daobing Hu; Guangmiao Wan; Hang Wang; Xu Wang; Cong Hu; Hongyuan Xu; Woosung Son - Web page: https://patentgrep.com/patent/US12183292B2 ## CPC - G09G 3/3406: {Control of illumination source (illumination devices structurally associated with liquid crystal cells G02F1/1336)} - G09G 3/32: semiconductive, e.g. using light-emitting diodes [LED] - G09G 2300/0842: forming a memory circuit, e.g. a dynamic memory with one capacitor - G09G 2310/08: Details of timing specific for flat panels, other than clock recovery - G09G 2320/064: by time modulation of the brightness of the illumination source - 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 backlight driving method and a display panel are provided. The backlight driving method provided by the present application uses pulse width modulation technology to modulate a low-level pulse width of a scan signal. By increasing a low-level pulse width to increase the pulse period, a number of high-level pulses is reduced, thereby reducing a high-level pulse time. Therefore, a time for a TFT to receive a high-level voltage is also reduced, thereby improving a stability of the TFT and also improving a problem of a threshold voltage drift of the TFT. ## Claims ### Claim 1 A backlight driving method, comprising steps of: providing a pulse width modulation signal; modulating a low-level pulse width of a scan signal to be modulated according to the pulse width modulation signal to increase a pulse period of the scan signal to be modulated, such that a number of high-level pulses of the modulated scan signal is less than a number of high-level pulses of the scan signal to be modulated; and outputting the modulated scan signal to a backlight driving circuit. ### Claim 2 (depends on 1) The backlight driving method according to claim 1, wherein the scan signal to be modulated in one frame includes a plurality of initial pulse periods, and wherein the step of the low-level pulse width of the scan signal to be modulated according to the pulse width modulation signal to increase the pulse period of the scan signal to be modulated, such that the number of high-level pulses of the modulated scan signal is less than the number of high-level pulses of the scan signal to be modulated, comprises: increasing the low-level pulse width, modulating at least one of the initial pulse periods into a first pulse period, and a time of the first pulse period is a time of at least two of the initial pulse periods, such that the modulated scan signal includes a plurality of the first pulse periods. ### Claim 3 (depends on 2) The backlight driving method according to claim 2, wherein the scan signal to be modulated in one frame includes 127 initial pulse periods, and wherein the step of the low-level pulse width of the scan signal to be modulated according to the pulse width modulation signal to increase the pulse period of the scan signal to be modulated, such that the number of high-level pulses of the modulated scan signal is less than the number of high-level pulses of the scan signal to be modulated, comprises: modulating the scan signal to be modulated in one frame to include one of the initial pulse periods and p of the first pulse periods, wherein the time of the first pulse period is the time of two of the initial pulse periods, and wherein a value of p is 63. ### Claim 4 (depends on 1) The backlight driving method according to claim 1, wherein the scan signal to be modulated in one frame includes a plurality of initial pulse periods, and wherein the step of the low-level pulse width of the scan signal to be modulated according to the pulse width modulation signal to increase the pulse period of the scan signal to be modulated, such that the number of high-level pulses of the modulated scan signal is less than the number of high-level pulses of the scan signal to be modulated, comprises: increasing the low-level pulse width, modulating at least one initial pulse period into a first pulse period, and modulating at least one initial pulse period into a second pulse period, such that the modulated scan signal includes a plurality of the first pulse periods and a plurality of second pulse periods, wherein a time of the initial pulse period is less than a time of the first pulse period, and the time of the first pulse period is less than a time of the second pulse period. ### Claim 5 (depends on 4) The backlight driving method according to claim 4, wherein the time of the first pulse period is the time of two of the initial pulse periods, and the time of the second pulse period is the time of four of the initial pulse periods. ### Claim 6 (depends on 1) The backlight driving method according to claim 1, wherein the scan signal to be modulated in one frame includes a plurality of initial pulse periods, and wherein the step of the low-level pulse width of the scan signal to be modulated according to the pulse width modulation signal to increase the pulse period of the scan signal to be modulated, such that the number of high-level pulses of the modulated scan signal is less than the number of high-level pulses of the scan signal to be modulated, comprises: increasing the low-level pulse width and modulating a plurality of initial pulse periods in a frame into n first pulse periods and m second pulse periods, such that the modulated scan signal in one frame includes one initial pulse period, n first pulse periods, and m second pulse periods, wherein a time of the first pulse period is a time of two of the initial pulse periods, and a time of the second pulse period is a time of four of the initial pulse periods, and wherein a sum of n and m is 32, and m and n are positive integers greater than 1. ### Claim 7 (depends on 6) The backlight driving method according to claim 6, wherein the scan signal to be modulated in one frame includes 127 initial pulse periods, and wherein the step of the low-level pulse width of the scan signal to be modulated according to the pulse width modulation signal to increase the pulse period of the scan signal to be modulated, such that the number of high-level pulses of the modulated scan signal is less than the number of high-level pulses of the scan signal to be modulated, comprises: modulating the scan signal to be modulated in one frame to include one initial pulse period, one first pulse period, and 31 second pulse periods. ### Claim 8 (depends on 7) The backlight driving method according to claim 7, wherein the modulated scan signal includes one of the initial pulse period, one of the first pulse period, and 31 of the second pulse periods, all of which are sequentially disposed. ### Claim 9 (depends on 1) The backlight driving method according to claim 1, wherein the backlight driving method is applied to a backlight driving circuit, and the backlight driving circuit includes a first transistor, a second transistor, a storage capacitor, and a light emitting device; a source of the first transistor is connected to a cathode of the light emitting device, a drain of the first transistor is grounded, and a gate of the first transistor is electrically connected to the first node; a source of the second transistor is connected to a data signal, a drain of the second transistor is electrically connected to a first node, and a gate of the second transistor is connected to the modulated scan signal; a first end of the storage capacitor is electrically connected to the first node, and a second end of the storage capacitor is grounded; and an anode of the light emitting device is connected to a power signal. ### Claim 10 (depends on 9) The backlight driving method according to claim 9, wherein, when the modulated scan signal is at a high-level, the data signal is at a high-level, and a high-level pulse width of the data signal is greater than a high-level pulse width corresponding to the modulated scan signal. ### Claim 11 A display panel, comprising a backlight module, wherein the backlight module is provided with a backlight driving circuit, and the backlight driving circuit is driven by a backlight driving method, wherein the backlight driving method comprises steps of: providing a pulse width modulation signal; modulating a low-level pulse width of a scan signal to be modulated according to the pulse width modulation signal to increase a pulse period of the scan signal to be modulated, such that a number of high-level pulses of the modulated scan signal is less than a number of high-level pulses of the scan signal to be modulated; and outputting the modulated scan signal to a backlight driving circuit. ### Claim 12 (depends on 11) The display panel according to claim 11, wherein the scan signal to be modulated in one frame includes a plurality of initial pulse periods, and wherein the step of the low-level pulse width of the scan signal to be modulated according to the pulse width modulation signal to increase the pulse period of the scan signal to be modulated, such that the number of high-level pulses of the modulated scan signal is less than the number of high-level pulses of the scan signal to be modulated, comprises: increasing the low-level pulse width, modulating at least one of the initial pulse periods into a first pulse period, and a time of the first pulse period is a time of at least two of the initial pulse periods, such that the modulated scan signal includes a plurality of the first pulse periods. ### Claim 13 (depends on 12) The display panel according to claim 12, wherein the scan signal to be modulated in one frame includes 127 initial pulse periods, and wherein the step of the low-level pulse width of the scan signal to be modulated according to the pulse width modulation signal to increase the pulse period of the scan signal to be modulated, such that the number of high-level pulses of the modulated scan signal is less than the number of high-level pulses of the scan signal to be modulated, comprises: modulating the scan signal to be modulated in one frame to include one of the initial pulse periods and p of the first pulse periods, wherein the time of the first pulse period is the time of two of the initial pulse periods, and wherein a value of p is 63. ### Claim 14 (depends on 11) The display panel according to claim 11, wherein the scan signal to be modulated in one frame includes a plurality of initial pulse periods, and wherein the step of the low-level pulse width of the scan signal to be modulated according to the pulse width modulation signal to increase the pulse period of the scan signal to be modulated, such that the number of high-level pulses of the modulated scan signal is less than the number of high-level pulses of the scan signal to be modulated, comprises: increasing the low-level pulse width, modulating at least one initial pulse period into a first pulse period, and modulating at least one initial pulse period into a second pulse period, such that the modulated scan signal includes a plurality of the first pulse periods and a plurality of second pulse periods, wherein a time of the initial pulse period is less than a time of the first pulse period, and the time of the first pulse period is less than a time of the second pulse period. ### Claim 15 (depends on 14) The display panel according to claim 14, wherein the time of the first pulse period is the time of two of the initial pulse periods, and the time of the second pulse period is the time of four of the initial pulse periods. ### Claim 16 (depends on 11) The display panel according to claim 11, wherein the scan signal to be modulated in one frame includes a plurality of initial pulse periods, and wherein the step of the low-level pulse width of the scan signal to be modulated according to the pulse width modulation signal to increase the pulse period of the scan signal to be modulated, such that the number of high-level pulses of the modulated scan signal is less than the number of high-level pulses of the scan signal to be modulated, comprises: increasing the low-level pulse width and modulating a plurality of initial pulse periods in a frame into n first pulse periods and m second pulse periods, such that the modulated scan signal in one frame includes one initial pulse period, n first pulse periods, and m second pulse periods, wherein a time of the first pulse period is a time of two of the initial pulse periods, and a time of the second pulse period is a time of four of the initial pulse periods, and wherein a sum of n and m is 32, and m and n are positive integers greater than 1. ### Claim 17 (depends on 16) The display panel according to claim 16, wherein the scan signal to be modulated in one frame includes 127 initial pulse periods, and wherein the step of the low-level pulse width of the scan signal to be modulated according to the pulse width modulation signal to increase the pulse period of the scan signal to be modulated, such that the number of high-level pulses of the modulated scan signal is less than the number of high-level pulses of the scan signal to be modulated, comprises: modulating the scan signal to be modulated in one frame to include one initial pulse period, one first pulse period, and 31 second pulse periods. ### Claim 18 (depends on 17) The display panel according to claim 17, wherein the modulated scan signal includes one of the initial pulse period, one of the first pulse period, and 31 of the second pulse periods, all of which are sequentially disposed. ### Claim 19 (depends on 11) The display panel according to claim 11, wherein the backlight driving method is applied to a backlight driving circuit, and the backlight driving circuit includes a first transistor, a second transistor, a storage capacitor, and a light emitting device; a source of the first transistor is connected to a cathode of the light emitting device, a drain of the first transistor is grounded, and a gate of the first transistor is electrically connected to the first node; a source of the second transistor is connected to a data signal, a drain of the second transistor is electrically connected to a first node, and a gate of the second transistor is connected to the modulated scan signal; a first end of the storage capacitor is electrically connected to the first node, and a second end of the storage capacitor is grounded; and an anode of the light emitting device is connected to a power signal. ### Claim 20 (depends on 19) The display panel according to claim 19, wherein, when the modulated scan signal is at a high-level, the data signal is at a high-level, and a high-level pulse width of the data signal is greater than a high-level pulse width corresponding to the modulated scan signal.