# US 12,223,894 B2 · Pixel driving circuit, driving method thereof 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 12,223,894 B2 - Document ID: US12223894B2 - Status: Granted - Kind: B2 - Application number: 17/913,428 - Filed: 2021-10-29 - Published: 2024-06-27 - Granted: 2025-02-11 - Earliest claimed: 2021-03-24 - Assignees: Mianyang Boe Optoelectronics Technology Co., Ltd.; Boe Technology Group Co., Ltd. - Applicants: Mianyang Boe Optoelectronics Technology Co., Ltd.; Boe Technology Group Co., Ltd. - Inventors: Yawei Zhu; Xin Cao; Zifeng Wang; Danfeng Wang; Haoyuan Fan - Web page: https://patentgrep.com/patent/US12223894B2 ## CPC - G09G 3/3233: with pixel circuitry controlling the current through the light-emitting element - G09G 2300/0426: Layout of electrodes and connections - G09G 2300/0465: Improved aperture ratio, e.g. by size reduction of the pixel circuit, e.g. for improving the pixel density or the maximum displayable luminance or brightness - G09G 2300/0819: used for counteracting undesired variations, e.g. feedback or autozeroing - G09G 2300/0842: forming a memory circuit, e.g. a dynamic memory with one capacitor - 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 2310/08: Details of timing specific for flat panels, other than clock recovery - G09G 2320/0233: Improving the luminance or brightness uniformity across the screen - 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 pixel driving circuit, a driving method thereof and a display panel are provided. The pixel driving circuit includes a driving transistor, a capacitor having two terminals connected to a first power terminal and a gate electrode of the driving transistor, and a light emitting device. The pixel driving circuit includes: a reset module; a data writing module; a threshold compensation module including a compensation transistor configured to electrically connect second and gate electrodes of the driving transistor together in the data writing phase; a light emitting control module including a first gating transistor configured to electrically connect the second electrode of the driving transistor and the light emitting device in the reset phase and disconnect the second electrode from the light emitting device in the data writing phase. The compensation transistor and the first gating transistor are oxide transistors, and the driving transistor is a low-temperature polysilicon transistor. ## Claims ### Claim 1 A pixel driving circuit, comprising a driving transistor, a capacitor and a light emitting device, wherein both terminals of the capacitor are connected to a first power terminal and a gate electrode of the driving transistor, respectively, wherein the pixel driving circuit further comprises: a reset module configured to transmit a signal at an initialization voltage terminal to the gate electrode of the driving transistor and a first terminal of the light emitting device in a reset phase, to initialize potentials at the gate electrode of the driving transistor and the first terminal of the light emitting device; a data writing module configured to write a data signal at a data writing terminal into a first electrode of the driving transistor in a data writing phase; a threshold compensation module comprising a compensation transistor, which is configured to electrically connect a second electrode and the gate electrode of the driving transistor together in the data writing phase; and a light emitting control module comprising a first gating transistor and configured to disconnect the first power terminal from the first electrode of the driving transistor in the reset phase and the data writing phase; wherein the first gating transistor is configured to electrically connect the second electrode of the driving transistor and the light emitting device in the reset phase and disconnect the second electrode of the driving transistor from the light emitting device in the data writing phase; the light emitting control module is configured to electrically connect the first power terminal and the first electrode of the driving transistor and electrically connect the second electrode of the driving transistor and the light emitting device in a light emitting phase; and wherein the compensation transistor is an oxide transistor, the driving transistor is a low-temperature polysilicon transistor, and the first gating transistor is an oxide transistor; wherein a first electrode of the first gating transistor is connected to the second electrode of the driving transistor, and a second electrode of the first gating transistor is connected to the first terminal of the light emitting device; the data writing module comprises a writing transistor; and a gate electrode of the first gating transistor and a gate electrode of the writing transistor are connected to a scan signal terminal, a first electrode of the writing transistor is connected to the data writing terminal, and a second electrode of the writing transistor is connected to the first electrode of the driving transistor. ### Claim 2 (depends on 1) The pixel driving circuit according to claim 1, wherein the light emitting control module further comprises a second gating transistor configured to disconnect the first power terminal from the first electrode of the driving transistor in the reset phase and the data writing phase, and electrically connect the first power terminal to the first electrode of the driving transistor in the light emitting phase. ### Claim 3 (depends on 2) The pixel driving circuit according to claim 2, wherein a gate electrode of the second gating transistor is connected to a light emitting control terminal, a first electrode of the second gating transistor is connected to the first power terminal, and a second electrode of the second gating transistor is connected to the first electrode of the driving transistor. ### Claim 4 (depends on 3) The pixel driving circuit according to claim 3, wherein a gate electrode of the compensation transistor is connected to the light emitting control terminal, a first electrode of the compensation transistor is connected to the second electrode of the driving transistor, and a second electrode of the compensation transistor is connected to the gate electrode of the driving transistor. ### Claim 5 (depends on 4) The pixel driving circuit according to claim 4, wherein the reset module comprises a reset transistor; a gate electrode of the reset transistor is connected to a reset terminal, a first electrode of the reset transistor is connected to the first terminal of the light emitting device, and a second electrode of the reset transistor is connected to the initialization voltage terminal; the second gating transistor, the writing transistor and the reset transistor are all low-temperature polysilicon transistors; the compensation transistor and the first gating transistor are N-type transistors; and the driving transistor, the second gating transistor, the writing transistor and the reset transistor are all P-type transistors. ### Claim 6 (depends on 5) The pixel driving circuit according to claim 5, further comprising a substrate, wherein the first gating transistor, the second gating transistor, the writing transistor, the reset transistor, the compensation transistor, the driving transistor, and the capacitor are on the substrate. ### Claim 7 (depends on 6) The pixel driving circuit according to claim 6, further comprising a first insulating layer, a second insulating layer, a third insulating layer, an interlayer dielectric layer, a planarization layer, and a pixel defining layer sequentially on the substrate, wherein an active layer of the driving transistor is between the substrate and the first insulating layer; the gate electrode of the driving transistor is on the active layer of the driving transistor and between the first insulating layer and the second insulating layer; the first electrode and the second electrode of the driving transistor are in a same layer and between the interlayer dielectric layer and the planarization layer; and the gate electrode of the compensation transistor, the gate electrode of the first gating transistor and the gate electrode of the driving transistor are in a same layer and between the first insulating layer and the second insulating layer; an active layer of the compensation transistor and an active layer of the first gating transistor are in a same layer and between the second insulating layer and the third insulating layer; and the first electrode and the second electrode of the compensation transistor, the first electrode and the second electrode of the first gating transistor and the first electrode and the second electrode of the driving transistor are in a same layer and between the interlayer dielectric layer and the planarization layer. ### Claim 8 (depends on 7) The pixel driving circuit according to claim 7, wherein active layers of the second gating transistor, the writing transistor and the reset transistor are in a same layer as the active layer of the driving transistor and between the substrate and the first insulating layer; the gate electrodes of the second gating transistor, the writing transistor and the reset transistor are in a same layer as the gate electrode of the driving transistor and between the first insulating layer and the second insulating layer; and the first electrodes and the second electrodes of the second gating transistor, the writing transistor and the reset transistor are in a same layer as the first electrode and the second electrode of the driving transistor and between the interlayer dielectric layer and the planarization layer. ### Claim 9 (depends on 8) The pixel driving circuit according to claim 8, wherein the gate electrode of the writing transistor and the gate electrode of the first gating transistor are on a same first scan signal line; and/or the gate electrode of the second gating transistor and the gate electrode of the compensation transistor are on a same light emitting signal line. ### Claim 10 (depends on 9) The pixel driving circuit according to claim 9, wherein the gate electrode of the reset transistor is on a reset signal line; and/or a first plate of the capacitor is in a same layer as the gate electrode of the driving transistor, and a second plate of the capacitor is connected to the first power terminal and in a same layer as a second scan signal line of the pixel driving circuit, which is different from the first scan signal line, wherein the second plate is directly above the first plate. ### Claim 11 (depends on 10) The pixel driving circuit according to claim 10, wherein the active layers of the driving transistor, the writing transistor, the second gating transistor and the reset transistor are made of low-temperature polysilicon; and the active layer of the compensation transistor and the active layer of the first gating transistor are made of an oxide material. ### Claim 12 (depends on 11) A driving method of the pixel driving circuit according to claim 11, the driving method comprises: in the reset phase, providing a first level signal to the reset terminal and providing a second level signal to the scan signal terminal and the light emitting control terminal; in the data writing phase, providing the second level signal to the reset terminal and the light emitting control terminal, and providing the first level signal to the scan signal terminal; and in the light emitting phase, providing the second level signal to the reset terminal and the scan signal terminal, and providing the first level signal to the light emitting control terminal. ### Claim 13 (depends on 8) The pixel driving circuit according to claim 8, wherein the active layers of the driving transistor, the writing transistor, the second gating transistor and the reset transistor are made of low-temperature polysilicon; and the active layer of the compensation transistor and the active layer of the first gating transistor are made of an oxide material. ### Claim 14 (depends on 9) The pixel driving circuit according to claim 9, wherein the active layers of the driving transistor, the writing transistor, the second gating transistor and the reset transistor are made of low-temperature polysilicon; and the active layer of the compensation transistor and the active layer of the first gating transistor are made of an oxide material. ### Claim 15 (depends on 1) A driving method of the pixel driving circuit according to claim 1, comprising: in the reset phase, turning on the first gating transistor and the compensation transistor, and transmitting, by the reset module, the signal at the initialization voltage terminal to the gate electrode of the driving transistor and the light emitting device through the first gating transistor and the compensation transistor, to control the driving transistor to be turned on; disconnecting, by the light emitting control module, the first power terminal from the first electrode of the driving transistor; in the data writing phase, writing, by the data writing module, the data signal at the data writing terminal into the first electrode of the driving transistor; electrically connecting, by the compensation transistor, the second electrode and the gate electrode of the driving transistor together; disconnecting, by the light emitting control module, the first power terminal from the first electrode of the driving transistor and disconnecting the second electrode of the driving transistor from the light emitting device; and in the light emitting phase, electrically connecting, by the light emitting control module, the first power terminal and the first electrode of the driving transistor together and electrically connecting the second electrode of the driving transistor and the light emitting device together. ### Claim 16 (depends on 1) A display panel, comprising the pixel driving circuit of claim 1. ### Claim 17 (depends on 16) The pixel driving circuit according to claim 16, wherein the reset module comprises a reset transistor; a gate electrode of the reset transistor is connected to a reset terminal, a first electrode of the reset transistor is connected to the first terminal of the light emitting device, and a second electrode of the reset transistor is connected to the initialization voltage terminal; the second gating transistor, the writing transistor and the reset transistor are all low-temperature polysilicon transistors; the compensation transistor and the first gating transistor are N-type transistors; and the driving transistor, the second gating transistor, the writing transistor and the reset transistor are all P-type transistors. ### Claim 18 (depends on 17) The pixel driving circuit according to claim 17, further comprising a substrate, wherein the first gating transistor, the second gating transistor, the writing transistor, the reset transistor, the compensation transistor, the driving transistor, and the capacitor are on the substrate. ### Claim 19 A pixel driving circuit, comprising a driving transistor, a capacitor and a light emitting device, wherein both terminals of the capacitor are connected to a first power terminal and a gate electrode of the driving transistor, respectively, wherein the pixel driving circuit further comprises: a reset module configured to transmit a signal at an initialization voltage terminal to the gate electrode of the driving transistor and a first terminal of the light emitting device in a reset phase, to initialize potentials at the gate electrode of the driving transistor and the first terminal of the light emitting device; a data writing module configured to write a data signal at a data writing terminal into a first electrode of the driving transistor in a data writing phase; a threshold compensation module comprising a compensation transistor, which is configured to electrically connect a second electrode and the gate electrode of the driving transistor together in the data writing phase; and a light emitting control module comprising a first gating transistor and configured to disconnect the first power terminal from the first electrode of the driving transistor in the reset phase and the data writing phase; wherein the first gating transistor is configured to electrically connect the second electrode of the driving transistor and the light emitting device in the reset phase and disconnect the second electrode of the driving transistor from the light emitting device in the data writing phase; the light emitting control module is configured to electrically connect the first power terminal and the first electrode of the driving transistor and electrically connect the second electrode of the driving transistor and the light emitting device in a light emitting phase; and wherein the compensation transistor is an oxide transistor, the driving transistor is a low-temperature polysilicon transistor, and the first gating transistor is an oxide transistor; the pixel driving circuit further comprises a substrate, and the first gating transistor, the compensation transistor and the driving transistor are on the substrate; and the pixel driving circuit further comprises a first insulating layer, a second insulating layer, a third insulating layer, an interlayer dielectric layer, a planarization layer, and a pixel defining layer sequentially on the substrate, wherein an active layer of the driving transistor is between the substrate and the first insulating layer; the gate electrode of the driving transistor is on the active layer of the driving transistor and between the first insulating layer and the second insulating layer; the first electrode and the second electrode of the driving transistor are in a same layer and between the interlayer dielectric layer and the planarization layer; and the gate electrode of the compensation transistor, the gate electrode of the first gating transistor and the gate electrode of the driving transistor are in a same layer and between the first insulating layer and the second insulating layer; an active layer of the compensation transistor and an active layer of the first gating transistor are in a same layer and between the second insulating layer and the third insulating layer; and the first electrode and the second electrode of the compensation transistor, the first electrode and the second electrode of the first gating transistor and the first electrode and the second electrode of the driving transistor are in a same layer and between the interlayer dielectric layer and the planarization layer. ### Claim 20 (depends on 19) The pixel driving circuit according to claim 19, wherein the light emitting control module further comprises a second gating transistor configured to disconnect the first power terminal from the first electrode of the driving transistor in the reset phase and the data writing phase, and electrically connect the first power terminal to the first electrode of the driving transistor in the light emitting phase; wherein a gate electrode of the second gating transistor is connected to a light emitting control terminal, a gate electrode of the first gating transistor is connected to a scan signal terminal, a first electrode of the second gating transistor is connected to the first power terminal, and a second electrode of the second gating transistor is connected to the first electrode of the driving transistor; and a first electrode of the first gating transistor is connected to the second electrode of the driving transistor, and a second electrode of the first gating transistor is connected to the first terminal of the light emitting device; wherein a gate electrode of the compensation transistor is connected to the light emitting control terminal, a first electrode of the compensation transistor is connected to the second electrode of the driving transistor, and a second electrode of the compensation transistor is connected to the gate electrode of the driving transistor; the data writing module comprises a writing transistor, and a gate electrode of the writing transistor is connected to the scan signal terminal, a first electrode of the writing transistor is connected to the data writing terminal, and a second electrode of the writing transistor is connected to the first electrode of the driving transistor; wherein the reset module comprises a reset transistor; a gate electrode of the reset transistor is connected to a reset terminal, a first electrode of the reset transistor is connected to the first terminal of the light emitting device, and a second electrode of the reset transistor is connected to the initialization voltage terminal; the second gating transistor, the writing transistor and the reset transistor are all low-temperature polysilicon transistors; the compensation transistor and the first gating transistor are N-type transistors; and the driving transistor, the second gating transistor, the writing transistor and the reset transistor are all P-type transistors; and the second gating transistor, the writing transistor, the reset transistor, and the capacitor are on the substrate.