# US 12,225,780 B2 · Display substrate, manufacturing method thereof, 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 12,225,780 B2 - Document ID: US12225780B2 - Status: Granted - Kind: B2 - Application number: 18/459,495 - Filed: 2023-09-01 - Published: 2023-12-21 - Granted: 2025-02-11 - Earliest claimed: 2017-06-14 - Assignees: Hefei Boe Optoelectronics Technology Co., Ltd.; Boe Technology Group Co., Ltd. - Applicants: Hefei Boe Optoelectronics Technology Co., Ltd.; Boe Technology Group Co., Ltd. - Inventors: Kui Gong; Xianxue Duan - Web page: https://patentgrep.com/patent/US12225780B2 ## CPC - H10K 59/122: Pixel-defining structures or layers, e.g. banks - H10D 84/01: Manufacture or treatment - H10D 86/01: Manufacture or treatment - H10D 86/021: {of multiple TFTs} - H10K 50/15: Hole transporting layers - H10K 50/16: Electron transporting layers - H10K 71/233: {by photolithographic etching} - H10K 71/621: {Providing a shape to conductive layers, e.g. patterning or selective deposition} - H10K 50/17: Carrier injection layers - H10K 50/171: {Electron injection layers} - H10K 59/1201: {Manufacture or treatment} - H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES ## Abstract A display substrate, a manufacturing method thereof, and a display device. The method includes: forming a pixel definition layer transitional pattern on a base substrate, the pixel definition layer transitional pattern being provided at a lateral surface with an undercut; forming a common layer, which is broken at the undercut, on the base substrate; removing the undercut to obtain a pattern of a pixel definition layer; and forming a cathode on the base substrate. ## Claims ### Claim 1 A display substrate, comprising a base substrate, a pixel definition layer arranged on the base substrate and a common layer, wherein the pixel definition layer comprises a first film layer and a second film layer, the first film layer is arranged at a side of the second film layer adjacent to the base substrate, and an orthogonal projection of a top surface of the first film layer onto the base substrate completely falls within an orthogonal projection of a bottom surface of the second film layer onto the base substrate, wherein the common layer is arranged on a top surface of the second film layer, an orthogonal projection of the common layer on the base substrate overlaps the orthogonal projection of the top surface of the first film layer onto the base substrate. ### Claim 2 (depends on 1) The display substrate according to claim 1, wherein an edge of the orthogonal projection of the top surface of the first film layer onto the base substrate is spaced apart by a certain distance from an edge of the orthogonal projection of the bottom surface of the second film layer onto the base substrate. ### Claim 3 (depends on 1) The display substrate according to claim 1, wherein the first film layer comprises a first dam member and a second dam member, the second dam member is arranged at a side of the first dam member away from the base substrate. ### Claim 4 (depends on 3) The display substrate according to claim 3, wherein an orthogonal projection of a top surface of the first dam member onto the base substrate coincides an orthogonal projection of a bottom surface of the second dam member onto the base substrate. ### Claim 5 (depends on 3) The display substrate according to claim 3, wherein an orthogonal projection of a bottom surface of the second dam member onto the base substrate completely falls within an orthogonal projection of a top surface of the first dam member onto the base substrate. ### Claim 6 (depends on 3) The display substrate according to claim 3, wherein an orthogonal projection of a top surface of the second dam member onto the base substrate completely falls within an orthogonal projection of a top surface of the first dam member onto the base substrate. ### Claim 7 (depends on 3) The display substrate according to claim 3, wherein the second film layer comprises a third dam member, an orthogonal projection of a top surface of the second dam member onto the base substrate completely falls within an orthogonal projection of a bottom surface of the third dam member onto the base substrate, and an edge of the orthogonal projection of the top surface of the second dam member onto the base substrate is spaced apart by a certain distance from an edge of the orthogonal projection of the bottom surface of the third dam member onto the base substrate. ### Claim 8 (depends on 7) The display substrate according to claim 7, wherein the first dam member, the second dam member, the third dam member have different patterns and/or thicknesses. ### Claim 9 (depends on 1) The display substrate according to claim 1, wherein the common layer is broken at a boundary between the first film layer and the second film layer. ### Claim 10 (depends on 8) The display substrate according to claim 8, wherein a sum of a thickness of the first dam member and a thickness of the second dam member is D, the thickness of the first dam member is 1/10D to ⅕D, a thickness of the third dam member is ⅕D to ⅓D. ### Claim 11 (depends on 1) A display device comprising the display substrate according to claim 1. ### Claim 12 A method for manufacturing a display substrate, comprising: forming a pixel definition layer transitional pattern on a base substrate, the pixel definition layer transitional pattern being provided at a lateral surface with an undercut; removing the undercut to obtain a pattern of a pixel definition layer; and forming the common layer on the base substrate; wherein the forming the pixel definition layer transitional pattern on the base substrate comprises: forming at least two dam members on the base substrate, wherein the at least two dam members are located in a direction perpendicular to the base substrate, the pixel definition layer transitional pattern comprises the at least two dam members, and the undercut is formed between two of the at least two dam members, wherein the forming the at least two dam members on the base substrate comprises: forming, on the base substrate, a first dam member, a second dam member arranged on the first dam member and a third dam member arranged on the second dam member, wherein an orthogonal projection of a top surface of the second dam member onto the base substrate completely falls within an orthogonal projection of a bottom surface of the third dam member onto the base substrate, and an edge of the orthogonal projection of the top surface of the second dam member onto the base substrate is spaced apart by a certain distance from an edge of the orthogonal projection of the bottom surface of the third dam member onto the base substrate, wherein the forming the common layer on the base substrate comprises: forming the common layer on the base substrate, wherein the common layer comprises a first common layer portion at a pixel region defined by the pixel definition layer transitional pattern and a second common layer portion at a top surface of the pixel definition layer transitional pattern. ### Claim 13 (depends on 12) The method according to claim 12, wherein the forming, on the base substrate, the first dam member, the second dam member arranged on the first dam member and the third dam member arranged on the second dam member comprises: forming a first photosensitive material layer; exposing a portion of the first photosensitive material layer having a thickness d relative to an upper surface of the first photosensitive material layer to form a fully exposed film layer, the first photosensitive material layer having a thickness D, and D being larger than d; forming a second photosensitive material layer on the exposed first photosensitive material layer; exposing portions of the first photosensitive material layer and the second photosensitive material layer not shielded by a light-shielding pattern of a mask plate, an orthogonal projection of the light-shielding pattern onto the base substrate overlapping an orthogonal projection of the pixel definition layer onto the base substrate; and developing the exposed first photosensitive material layer and the exposed second photosensitive material layer to form the first dam member, the second dam member and the third dam member. ### Claim 14 (depends on 13) The method according to claim 13, wherein the thickness d of the fully exposed film layer is 1/10D to ⅕D. ### Claim 15 (depends on 14) The method according to claim 14, wherein a thickness d1 of the second photosensitive material layer is ⅕D to ⅓D, and d1 is larger than d. ### Claim 16 (depends on 12) The method according to claim 12, wherein the forming, on the base substrate, the second dam member and the third dam member arranged on the second dam member comprises: forming a first photosensitive material layer; exposing the entire first photosensitive material layer; forming a second photosensitive material layer on the exposed first photosensitive material layer; exposing portions of the first photosensitive material layer and the second photosensitive material layer not shielded by a light-shielding pattern of a mask plate, an orthogonal projection of the light-shielding pattern onto the base substrate overlapping an orthogonal projection of the pixel definition layer onto the base substrate; and developing the exposed first photosensitive material layer and the exposed second photosensitive material layer to form the second dam member and the third dam member. ### Claim 17 The method according to 12, wherein the first common layer portion and the second common layer portion are unconnected to each other. ### Claim 18 (depends on 12) The method according to claim 12, wherein the forming the common layer on the base substrate comprises: forming a hole injection layer and a hole transport layer sequentially on the base substrate, each of the hole injection layer and the hole transport layer being broken at the undercut at the lateral surface of the pixel definition layer transitional pattern, one portion of each of the hole injection layer and the hole transport layer being located at the pixel region, the other portion being located at the top surface of the pixel definition transitional pattern; and forming an electron transport layer and an electron injection layer sequentially, each of the electron transport layer and the electron injection layer being broken at the undercut at the lateral surface of the pixel definition layer transitional pattern, one portion of each of the electron transport layer and the electron injection layer being located at the pixel region, the other portion being located at the top surface of the pixel definition transitional pattern. ### Claim 19 (depends on 12) The method according to claim 12, further comprising: forming a cathode on the base substrate.