OLED pixel circuit and driving method for improving light emitting efficiency

• US 10,446,082 B2
• Filed: 07/05/2016
• Issued: 10/15/2019
• Est. Priority Date: 01/26/2016
• Status: Active Grant

• Current Assignee: BOE Technology Group Co., Ltd.
• Original Assignee: BOE Technology Group Co., Ltd.
• Inventors: Hao, Xueguang, Cheng, Hongfei, Ma, Zhanjie, Qiao, Yong, Wu, Xinyin
• Primary Examiner(s): Chatly, Amit
• Assistant Examiner(s): Lam, Nelson
• Application Number:
  US15/328,736
• Publication Number:
  US 20180053469A1
• Time in Patent Office: 1,197 Days
• Field of Search: 345 76- 83, 3151693
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• 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 2300/0866 by means of changes in the pixel supply voltage
• CPC Class Codes: G09G 2310/0264 Details of driving circuits
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/325 the data current flowing through the driving transistor during a setting phase, e.g. by using a switch for connecting the driving transistor to the data driver
• CPC Class Codes: G09G 3/3258 with pixel circuitry controlling the voltage across the light-emitting element
• CPC Class Codes: G09G 3/3283 in which the data driver supplies a variable data current for setting the current through, or the voltage across, the light-emitting elements

Abstract

The disclosure provides a pixel circuit including a reset module, a data write module, a storage module, a compensation and hold module, a drive module, and a light emitting device. The reset module is connected to the storage module and the light emitting device. The data write module is connected to the drive module. The compensation and hold module is connected to the drive module and the storage module. The storage module is connected to the drive module. The drive module is connected to the light emitting device.

Claims

1. A pixel circuit comprising:

a reset module;

a data write module;

a storage module;

a compensation and hold module;

a drive module; and

a light emitting device, wherein the reset module is connected to the storage module and the light emitting device, wherein the data write module is connected to the drive module, wherein the compensation and hold module is connected to the drive module and the storage module, wherein the storage module is connected to the drive module, and wherein the drive module is connected to the light emitting device;

wherein the reset module is configured to reset the storage module and the light emitting device, wherein the data write module is configured to provide a data current, wherein the compensation and hold module is configured to generate a control voltage for the drive module, wherein the control voltage is a function of data current, wherein the compensation and hold module is further configured to hold the control voltage, wherein the storage module is configured to store the control voltage, wherein the drive module is configured to generate a drive current according to the control voltage, and wherein the light emitting device is configured to emit light under the drive current;

wherein the data write module comprises a first transistor, wherein a control electrode of the first transistor is connected to a second voltage line, wherein a first electrode of the first transistor is directly connected to the drive module and the light emitting device, and wherein a second electrode of the first transistor is connected to a data current line; and

wherein the compensation and hold module comprises a third transistor, wherein a control electrode of the third transistor is connected to the second voltage line, wherein a first electrode of the third transistor is connected to a first voltage line, and wherein a second electrode of the third transistor is connected to the drive module and the storage module.

2. The pixel circuit according to claim 1, wherein the reset module comprises a fourth transistor, wherein a control electrode of the fourth transistor is connected to the second voltage line, wherein a first electrode of the fourth transistor is connected to the storage module and the light emitting device, and wherein a second electrode of the fourth transistor is connected to a third voltage line.

3. The pixel circuit according to claim 1, wherein the drive module comprises a second transistor, wherein a first electrode of the second transistor is connected to the first voltage line, and wherein the storage module is connected between a control electrode and a second electrode of the second transistor.

4. The pixel circuit according to claim 1, wherein the storage module comprises a capacitor, and wherein the drive module is connected between first and second ends of the capacitor.

5. The pixel circuit according to claim 1, wherein the third transistor is an N-type MOS transistor.

6. The pixel circuit according to claim 1, wherein the third transistor is a P-type MOS transistor.

7. A method for driving the pixel circuit according to claim 1, the method comprising:

a first stage including i) providing a data current by the data write module, and ii) turning on the drive module, the data write module, the compensation and hold module, and the reset module, wherein the compensation and hold module generates the control voltage and the storage module stores the control voltage, and wherein the control voltage is a function of data current; and

a second stage including i) turning on the drive module, and ii) laming off the data write module, the compensation and hold module, and the reset module, wherein the drive module generates a drive current according to the control voltage stored in the storage module, and wherein the light emitting device emits light under the drive current.

8. A display panel comprising the pixel circuit according to claim 1.

9. A display device comprising the display panel according to claim 8.

10. The display panel according to claim 8, wherein the reset module comprises a fourth transistor, wherein a control electrode of the fourth transistor is connected to the second voltage line, wherein a first electrode of the fourth transistor is connected to the storage module and the light emitting device, and wherein a second electrode of the fourth transistor is connected to a third voltage line.

11. The display panel according to claim 8, wherein the drive module comprises a second transistor, wherein a first electrode of the second transistor is connected to the first voltage line, and wherein the storage module is connected between a control electrode and a second electrode of the second transistor.

12. The display panel according to claim 8, wherein the storage module comprises a capacitor, and wherein the drive module is connected between first and second ends of the capacitor.

13. The display panel according to claim 8, wherein the third transistor is an N-type MOS transistor.

14. The display panel according to claim 8, wherein the third transistor is a P-type MOS transistor.