AMOLED PIXEL DRIVING CIRCUIT AND DRIVING METHOD THEREOF, AND ARRAY SUBSTRATE

• US 20160055797A1
• Filed: 08/22/2014
• Published: 02/25/2016
• Est. Priority Date: 10/25/2013
• Status: Active Grant

• Current Assignee: BOE Technology Group Co., Ltd., Chengdu BOE Optoelectronics Technology Company Limited (BOE Technology Group Co., Ltd.)
• Original Assignee: BOE Technology Group Co., Ltd., Chengdu BOE Optoelectronics Technology Company Limited (BOE Technology Group Co., Ltd.)
• Inventors: TAN, Wen, QI, Xiaojing
• Granted Patent: US 9,489,893 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G09G 2300/0408 Integration of the drivers onto the display substrate
• CPC Class Codes: G09G 2300/0819 used for counteracting undesired variations, e.g. feedback or autozeroing
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/0852 being a dynamic memory with more than one capacitor
• CPC Class Codes: 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
• CPC Class Codes: G09G 3/3208 organic, e.g. using organic light-emitting diodes [OLED]
• CPC Class Codes: G09G 3/3225 using an active matrix
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3258 with pixel circuitry controlling the voltage across the light-emitting element

Abstract

There are disclosed an AMOLED pixel driving circuit and driving method thereof, and array substrate. The AMOLED pixel driving circuit comprises a driving thin film transistor (T1), and a gate initial voltage writing module (T2) configured to write an initial voltage signal into a gate of the driving thin film transistor (T1), a first terminal of a storage capacitor (C1), and a second terminal of the coupling capacitor (C2); a data voltage writing module (T3) configured to write a data voltage signal into a source of the driving thin film transistor (T1); a saturation discharging module (T4) configured to connect or disconnect a first terminal of a coupling capacitor (C2) with or from the drain of the driving thin film transistor (T1); an initializing module (T5) configured to connect or disconnect the source of the driving thin film transistor (T1) with or from the second power supply (Vss); and a light emitting control module (T6) configured to connect or disconnect one terminal of the organic light emitting diode (D1) with or from a drain of the driving thin film transistor (T1); the storage capacitor (C1); the coupling capacitor (C2); and an organic light emitting diode (D1). The AMOLED pixel driving circuit and driving method thereof can realize the purpose of sub-threshold saturation turn-off and compensating for threshold voltage of the driving TFT.

Claims

1. An AMOLED pixel driving circuit comprising a driving thin film transistor, a storage capacitor, and an organic light emitting diode, wherein it further comprises:

a coupling capacitor connected to a first terminal of the storage capacitor;

a gate initial voltage writing module configured to write an initial voltage signal into a gate of the driving thin film transistor, the first terminal of the storage capacitor, and a second terminal of the coupling capacitor;

a data voltage writing module configured to write a data voltage signal into a source of the driving thin film transistor;

an initializing module configured to initialize a voltage at the source of the driving thin film transistor;

a light emitting control module configured to control one terminal of the organic light emitting diode to be connected to a drain of the driving thin film transistor; and

a saturation discharging module connected between a first terminal of the coupling capacitor and the drain of the driving thin film transistor.

2. The pixel driving circuit according to claim 1, wherein the gate initial voltage writing module comprise a second thin film transistor, whose source is connected to the first terminal of the storage capacitor, the second terminal of the coupling capacitor and the gate of the driving thin film transistor, gate is connected to a gate signal of a previous row, and drain is connected to an initial voltage signal terminal.

3. The pixel driving circuit according to claim 2, wherein the data voltage writing module comprises a third thin film transistor, whose gate is connected to a gate signal of a current row, drain is connected to the source of the driving thin film transistor, and source is connected to a data voltage signal terminal.

4. The pixel driving circuit according to claim 3, wherein the saturation discharging module comprises a fourth thin film transistor, whose drain is connected to the first terminal of the coupling capacitor, gate is connected to a first control signal line, and source is connected to the drain of the driving thin film transistor.

5. The pixel driving circuit according to claim 4, wherein the initializing module comprises a fifth thin film transistor, whose source is connected to the source of the driving thin film transistor, gate is connected to a second control signal line, and drain and the terminal of the storage capacitor are jointly connected to a second power supply.

6. The pixel driving circuit according to claim 5, wherein the light-emitting control module comprises a sixth thin film transistor, whose source is connected to the drain of the driving thin film transistor, gate is connected to the second control signal line, and drain is connected to the one terminal of the organic light emitting diode whose other terminal is connected to a first power supply.

7. The pixel driving circuit according to claim 6, wherein the driving thin film transistor, the second thin film transistor, the third thin film transistor, the fourth thin film transistor, the fifth thin film transistor, and the sixth thin film transistor are N type depletion thin film transistors.

8. The pixel driving circuit according to claim 1, wherein the initial voltage signal is a data voltage signal.

9. An array substrate comprising the pixel driving circuit according to claim 1.

12. The array substrate according to claim 9, wherein the gate initial voltage writing module comprise a second thin film transistor, whose source is connected to the first terminal of the storage capacitor, the second terminal of the coupling capacitor and the gate of the driving thin film transistor, gate is connected to a gate signal of a previous row, and drain is connected to an initial voltage signal terminal.

13. The array substrate according to claim 12, wherein the data voltage writing module comprises a third thin film transistor, whose gate is connected to a gate signal of a current row, drain is connected to the source of the driving thin film transistor, and source is connected to a data voltage signal terminal.

14. The array substrate according to claim 13, wherein the saturation discharging module comprises a fourth thin film transistor, whose drain is connected to the first terminal of the coupling capacitor, gate is connected to a first control signal line, and source is connected to the drain of the driving thin film transistor.

15. The array substrate according to claim 14, wherein the Initializing module comprises a fifth thin film transistor, whose source is connected to the source of the driving thin film transistor, gate is connected to a second control signal line, and drain and the terminal of the storage capacitor are jointly connected to a second power supply.

16. The array substrate according to claim 15, wherein the light-emitting control module comprises a sixth thin film transistor, whose source is connected to the drain of the driving thin film transistor, gate is connected to the second control signal line, and drain is connected to the one terminal of the organic light emitting diode whose other terminal is connected to a first power supply.

17. The array substrate according to claim 16, wherein the driving thin film transistor, the second thin film transistor, the third thin film transistor, the fourth thin film transistor, the fifth thin film transistor, and the sixth thin film transistor are N type depletion thin film transistors.

18. The array substrate according to claim 9, wherein the initial voltage signal is a data voltage signal.

10. A driving method of an AMOLED pixel driving circuit, wherein the pixel driving circuit comprises:

a driving thin film transistor, a gate initial voltage writing module, a data voltage writing module, a saturation discharging module, an initializing module, a light emitting control module, a storage capacitor, a coupling capacitor, and an organic light emitting diode, the driving method comprising steps of;

in an initializing phase;

writing an initial voltage signal into a gate of the driving thin film transistor, a first terminal of the storage capacitor and a second terminal of the coupling capacitor by the gate initial voltage writing module;

disconnecting a data voltage signal terminal from a source of the driving thin film transistor by the data voltage writing module;

connecting the source of the driving thin film transistor with a second power supply by the initializing module;

charging a second terminal of the storage capacitor by the second power supply;

connecting one terminal of the organic light emitting diode with a drain of the driving thin film transistor by the light emitting control module;

connecting a first terminal of the coupling capacitor with the drain of the driving thin film transistor by the saturation discharging module; and

charging the first terminal of the coupling capacitor through the organic light emitting diode by a first power supply;

in a threshold voltage compensating and data voltage writing phase;

disconnecting the initial voltage signal terminal from the gate of the driving thin film transistor, the first terminal of the storage capacitor and the second terminal of coupling capacitor by the gate initial voltage writing module;

connecting the data voltage signal terminal with the source of the driving thin film transistor by the data voltage writing module to write a data voltage signal into the source of the driving thin film transistor;

disconnecting the source of the driving thin film transistor from the second power supply by the initializing module;

disconnecting the one terminal of the organic light emitting diode from the drain of the driving thin film transistor by the light emitting control module;

connecting the first terminal of the coupling capacitor with the drain of the driving thin film transistor by the saturation discharging module; and

discharging the storage capacitor and the coupling capacitor through the driving thin film transistor;

in a light emitting phase;

disconnecting the initial voltage signal terminal from the gate of the driving thin film transistor, the first terminal of the storage capacitor and the second terminal of coupling capacitor by the gate initial voltage writing module;

disconnecting the data voltage signal terminal from the source of the driving thin film transistor by the data voltage writing module;

connecting the source of the driving thin film transistor with the second power supply by the initializing module;

connecting the one terminal of the organic light emitting diode with the drain of the driving thin film transistor by the light emitting control module;

disconnecting the first terminal of the coupling capacitor from the drain of the driving thin film transistor by the saturation discharging module; and

providing a driving current for the organic light emitting diode by the driving thin film transistor.

11. The driving method according to claim 10, wherein the gate initial voltage writing module comprises a second thin film transistor, the data voltage writing module comprises a third thin film transistor, the saturation discharging module comprises a fourth thin film transistor, the initializing module comprises a fifth thin film transistor, and the light emitting control module comprises a sixth thin film transistor, the driving method comprising:

in the initializing phase;

turning on the second thin film transistor, the fourth thin film transistor, the fifth thin film transistor and the sixth thin film transistor, and turning off the third thin film transistor;

writing the initial voltage signal into the gate of the driving thin film transistor, the first terminal of the storage capacitor and the second terminal of the coupling capacitor;

charging the second terminal of the storage capacitor by the second power supply; and

charging the first terminal of the coupling capacitor by the first power supply;

in the threshold voltage compensating and data voltage writing phase;

turning on the third thin film transistor and the fourth thin film transistor, and turning off the second thin film transistor, the fifth thin film transistor and the sixth thin film transistor;

writing the data voltage signal into the source of the driving thin film transistor, and discharging the storage capacitor and the coupling capacitor through the driving thin film transistor;

in the light emitting phase;

turning on the fifth transistor and the sixth thin film transistor, and turning off the second thin film transistor, the third thin film transistor and the fourth thin film transistor; and

providing the driving current for the light emitting diode by the driving thin film transistor.