# US 12,217,719 B2 · Pixel driving circuit 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 12,217,719 B2 - Document ID: US12217719B2 - Status: Granted - Kind: B2 - Application number: 17/272,244 - Filed: 2020-12-31 - Published: 2024-02-01 - Granted: 2025-02-04 - Earliest claimed: 2020-12-31 - Assignees: Tcl China Star Optoelectronics Technology Co., Ltd. - Applicants: Tcl China Star Optoelectronics Technology Co., Ltd. - Inventors: Yan Li - Web page: https://patentgrep.com/patent/US12217719B2 ## CPC - G09G 3/32: semiconductive, e.g. using light-emitting diodes [LED] - G09G 3/3688: {suitable for active matrices only} - G09G 3/3413: {Details of control of colour illumination sources} - G09G 3/3677: {suitable for active matrices only} - G09G 2300/0443: with several sub-pixels for the same colour in a pixel, not specifically used to display gradations (G09G3/364 takes precedence) - 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 2300/0828: forming a digital to analog [D/A] conversion circuit - G09G 2300/0842: forming a memory circuit, e.g. a dynamic memory with one capacitor - G09G 2320/0626: for control of overall brightness - 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 The present application provides a pixel driving circuit and a display device. The pixel driving circuit includes a scanning signal line and a data signal line. A pixel driving circuit unit includes at least two cascaded units, wherein the pixel driving circuit unit is configured to change a connection number of cascaded units that are connected to the data signal line and a light emitting diode, to adjust a brightness of the light emitting diode so as to effectively improve gray level of displayed picture and display quality. ## Claims ### Claim 1 A pixel driving circuit, comprising: a scanning signal line; at least two data signal lines arranged with the scanning signal line in an interleaved manner; a light emitting diode, having a first end electrically coupled to a voltage source; and a pixel driving circuit unit, comprising at least two cascaded units, each cascaded unit having a first electrode electrically coupled to a corresponding data signal line, and a second electrode electrically coupled to a second end of the light emitting diode; wherein the pixel driving circuit unit is configured to change a connection number of the cascaded units being connected to the data signal lines and the light emitting diode, such that a brightness of the light emitting diode is adjusted accordingly; wherein: each cascaded unit comprises a switching thin film transistor and a driving thin film transistor; a source of the switching thin film transistor is electrically coupled to the corresponding data signal line; a gate of the switching thin film transistor is electrically coupled to the corresponding scanning signal line; a drain of the switching thin film transistor is electrically coupled to a gate of the corresponding driving thin film transistor; and the switching thin film transistor and the driving thin film transistor comprise at least one of N-type thin film transistors or P-type thin film transistors; wherein the at least two cascaded units share the scanning signal line, and the scanning signal line is connected to the gate of the switching thin film transistor in each cascaded unit; and the at least two cascaded units share a capacitor having one end grounded and another end connected to the drain of the switching thin film transistor and the gate of the driving thin film transistor in each cascaded unit. ### Claim 2 (depends on 1) The pixel driving circuit according to claim 1, wherein: the pixel driving circuit unit comprises a first cascaded unit, a second cascaded unit, a third cascaded unit, and a fourth cascaded unit; the first cascaded unit comprises a first switching thin film transistor and a first driving thin film transistor; wherein: a drain of the first switching thin film transistor is coupled to a gate of the first driving thin film transistor; a drain of the first driving thin film transistor is coupled to the second end of the light emitting diode; and a source of the first driving thin film transistor is grounded; the second cascaded unit comprises a second switching thin film transistor and a second driving thin film transistor, wherein: a drain of the second switching thin film transistor is coupled to a gate of the second driving thin film transistor; a drain of the second driving thin film transistor is coupled to the second end of the light emitting diode, and a source of the second driving thin film transistor is grounded; the third cascaded unit comprises a third switching thin film transistor and a third driving thin film transistor, wherein: a drain of the third switching thin film transistor is coupled to a gate of the third driving thin film transistor, a drain of the third driving thin film transistor is coupled to the second end of the light emitting diode, and a source of the third driving thin film transistor is grounded; and the fourth cascaded unit comprises a fourth switching thin film transistor and a fourth driving thin film transistor, wherein: a drain of the fourth switching thin film transistor is coupled to a gate of the fourth driving thin film transistor; a drain of the fourth driving thin film transistor is electrically coupled to the second end of the light emitting diode; and a source of the fourth driving thin film transistor is grounded. ### Claim 3 (depends on 2) The pixel driving circuit according to claim 2, wherein the first driving thin film transistor, the second driving thin film transistor, the third driving thin film transistor, and the fourth driving thin film transistor are different. ### Claim 4 (depends on 3) The pixel driving circuit according to claim 3, wherein width-to-length ratios of channels in the first, second, third, and fourth driving thin film transistors are different. ### Claim 5 (depends on 2) The pixel driving circuit according to claim 2, wherein: the pixel driving circuit further comprises a first data signal line, a second data signal line, a third data signal line, and a fourth data signal line; the first data signal line is coupled to a source of the first switching thin film transistor; the second data signal line is coupled to a source of the second switching thin film transistor; the third data signal line is coupled to a source of the third switching thin film transistor; and the fourth data signal line is coupled to a source of the fourth switching thin film transistor. ### Claim 6 (depends on 1) The pixel driving circuit according to claim 1, wherein the light emitting diode comprises a first light emitting diode, a second light emitting diode, a third light emitting diode, and a fourth light emitting diode each respectively coupled to a second electrode of different cascaded units. ### Claim 7 A pixel driving circuit, comprising: a scanning signal line; at least two data signal lines arranged with the scanning signal line in an interleaved manner; a light emitting diode, having a first end electrically coupled to a voltage source; and a pixel driving circuit unit, comprising at least two cascaded units, each cascaded unit having a first electrode electrically coupled to a corresponding data signal line, and a second electrode electrically coupled to a second end of the light emitting diode; wherein the pixel driving circuit unit is configured to change a connection number of the cascaded units being connected to the data signal lines and the light emitting diode, such that a brightness of the light emitting diode is adjusted accordingly, wherein the light emitting diode comprises a first light emitting diode, a second light emitting diode, a third light emitting diode, and a fourth light emitting diode each respectively coupled to a second electrode of different cascaded units. ### Claim 8 (depends on 7) The pixel driving circuit according to claim 7, wherein: each cascaded unit comprises a switching thin film transistor and a driving thin film transistor; a source of the switching thin film transistor is electrically coupled to the corresponding data signal line; a gate of the switching thin film transistor is electrically coupled to the corresponding scanning signal line; a drain of the switching thin film transistor is electrically coupled to a gate of the corresponding driving thin film transistor; a drain of the driving thin film transistor is electrically coupled to the second end of the light emitting diode; and a source of the driving thin film transistor is grounded. ### Claim 9 (depends on 8) The pixel driving circuit according to claim 8, wherein each cascaded unit further comprises a capacitor having one end grounded and another end electrically coupled to the drain of the switching thin film transistor and the gate of the driving thin film transistor. ### Claim 10 (depends on 9) The pixel driving circuit according to claim 9, wherein: the at least two cascaded units share the scanning signal line, and the scanning signal line is connected to the gate of the switching thin film transistor in each cascaded unit; and the at least two cascaded units share the capacitor having one end grounded and another end electrically coupled to the drain of the switching thin film transistor and the gate of the driving thin film transistor in each cascaded unit. ### Claim 11 (depends on 7) The pixel driving circuit according to claim 7, wherein: the pixel driving circuit unit comprises a first cascaded unit, a second cascaded unit, a third cascaded unit, and a fourth cascaded unit; the first cascaded unit comprises a first switching thin film transistor and a first driving thin film transistor; wherein: a drain of the first switching thin film transistor is coupled to a gate of the first driving thin film transistor; a drain of the first driving thin film transistor is coupled to the second end of the light emitting diode; and a source of the first driving thin film transistor is grounded; the second cascaded unit comprises a second switching thin film transistor and a second driving thin film transistor, wherein: a drain of the second switching thin film transistor is coupled to a gate of the second driving thin film transistor; a drain of the second driving thin film transistor is coupled to the second end of the light emitting diode, and a source of the second driving thin film transistor is grounded; the third cascaded unit comprises a third switching thin film transistor and a third driving thin film transistor, wherein: a drain of the third switching thin film transistor is coupled to a gate of the third driving thin film transistor, a drain of the third driving thin film transistor is coupled to the second end of the light emitting diode, and a source of the third driving thin film transistor is grounded; and the fourth cascaded unit comprises a fourth switching thin film transistor and a fourth driving thin film transistor, wherein: a drain of the fourth switching thin film transistor is coupled to a gate of the fourth driving thin film transistor; a drain of the fourth driving thin film transistor is electrically coupled to the second end of the light emitting diode; and a source of the fourth driving thin film transistor is grounded. ### Claim 12 (depends on 11) The pixel driving circuit according to claim 11, wherein the first driving thin film transistor, the second driving thin film transistor, the third driving thin film transistor, and the fourth driving thin film transistor are different. ### Claim 13 (depends on 12) The pixel driving circuit according to claim 12, wherein width-to-length ratios of channels in the first, second, third, and fourth driving thin film transistors are different. ### Claim 14 (depends on 11) The pixel driving circuit according to claim 11, wherein: the pixel driving circuit further comprises a first data signal line, a second data signal line, a third data signal line, and a fourth data signal line; the first data signal line is coupled to a source of the first switching thin film transistor; the second data signal line is coupled to a source of the second switching thin film transistor; the third data signal line is coupled to a source of the third switching thin film transistor; the third data signal line is coupled to a source of the third switching thin film transistor; and the fourth data signal line is coupled to a source of the fourth switching thin film transistor. ### Claim 15 A display device comprising a display panel and a backlight source, wherein: the backlight source is connected to the display panel, configured to provide backlight for the display panel; the display panel comprises a pixel driving circuit comprising: a scanning signal line; at least two data signal lines arranged with the scanning signal line in an interleaved manner; a light emitting diode, having a first end electrically coupled to a voltage source; and a pixel driving circuit unit, comprising at least two cascaded units, each cascaded unit having one end electrically coupled to a corresponding data signal line, and another end electrically coupled to a second end of the light emitting diode; and wherein the pixel driving circuit unit is configured to change a connection number of the cascaded units being connected to the data signal lines and the light emitting diode, such that a brightness of the light emitting diode is adjusted accordingly; wherein each cascaded unit comprises a switching thin film transistor and a driving thin film transistor, and a capacitor having one end grounded and another end; a source of the switching thin film transistor is electrically coupled to the corresponding data signal line; a gate of the switching thin film transistor is electrically coupled to the corresponding scanning signal line; a drain of the switching thin film transistor is electrically coupled to a gate of the corresponding driving thin film transistor and the another end of the capacitor; a drain of the driving thin film transistor is electrically coupled to the second end of the light emitting diode; and a source of the driving thin film transistor is grounded; wherein the at least two cascaded units share the scanning signal line, and the scanning signal line is connected to the gate of the switching thin film transistor in each cascaded unit; and the at least two cascaded units share the capacitor having one end grounded and another end electrically coupled to the drain of the switching thin film transistor and the gate of the driving thin film transistor in each cascaded unit.