Pixel Circuit, Organic Electroluminescent Display Panel and Display Device

• US 20160372030A1
• Filed: 05/14/2015
• Published: 12/22/2016
• Est. Priority Date: 12/24/2014
• Status: Active Grant

• Current Assignee: BOE Technology Group Co., Ltd.
• Original Assignee: BOE Technology Group Co., Ltd.
• Inventors: Nagayama, Kazuyoshi, Song, Song
• Granted Patent: US 9,837,019 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 2310/0248 Precharge or discharge of column electrodes before or after applying exact column voltages
• CPC Class Codes: G09G 2310/061 for resetting or blanking
• CPC Class Codes: G09G 2320/0204 Compensation of DC component across the pixels in flat panels
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 3/32 semiconductive, e.g. using light-emitting diodes [LED]
• 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

Abstract

A pixel circuit, an organic electroluminescent display panel and a display device in a reset and compensation phase, a charge control module of the pixel circuit makes a data signal end and the first input end of a reset control module switch on, and the reset control module resets the control end and a output end of a drive module and compensates reference voltage; in a data writing phase, the charge control module writes the data signal inputted by the data signal end to the first input end of the reset control module; in a light-emitting phase, a light-emitting control module makes the output end of the drive module and the input end of the light emitting device switch on and drives the light emitting device to emit light by integrating the data signal inputted into the drive module with the reference voltage signal compensated into the drive module, which realizes the effect that the drive current driving the light emitting device to emit light is irrelevant to the power supply voltage signal, eliminates the influence on luminous brightness of the light emitting device caused by IR drop of the power supply voltage signal inputted into the pixel circuits, and further guaranteeing the display effect of the display panel.

Claims

1. A pixel circuit, comprising:

a charge control module, a drive module, a reset control module, a light-emitting control module and a light emitting device;

wherein

a control end of the charge control module is connected with a scan signal end, an input end thereof is connected with a data signal end, and an output end thereof is connected with the first input end of the reset control module;

a control end of the reset control module is connected with a threshold voltage signal end, the second input end is connected with a reference signal end and an input end of the drive module, respectively, the first output end is connected with a control end of the drive module, and the second output end is connected with an output end of the drive module and an input end of the light-emitting control module, respectively;

a control end of the light-emitting control module is connected with a light-emitting signal end, an output end thereof is connected with an input end of the light emitting device; and

an output end of the light emitting device is connected with a low level signal end;

in the reset and compensation phase, the charge control module makes the data signal end and the first input end of the reset control module switch on under the control of the scan signal end;

the reset control module resets the control end and the output end of the drive module and compensates reference voltage under the control of the threshold voltage signal end and the reference signal end;

in the data writing phase, the charge control module writes the data signal inputted by the data signal end to the first input end of the reset control module under the control of the scan signal end;

in the light-emitting phase, the light-emitting control module makes the output end of the drive module and the input end of the light emitting device switch on to drive the light emitting device to emit light under the control of the light-emitting signal end.

2. The pixel circuit according to claim 1, the reset control module comprises:

a first capacitor, a second capacitor, and a first switching transistor;

wherein

the gate of the first switching transistor is connected with a threshold voltage signal end, the source thereof is connected with a control end of the drive module, and the drain thereof is connected with an output end of the drive module and an input end of the light-emitting control module, respectively;

the first capacitor is connected between an output end of the charge control module and a control end of the drive module; and

the second capacitor is connected between the reference signal end and the control end of the drive module.

3. The pixel circuit according to claim 2, wherein, in the reset phase, the first switching transistor is turned on under the control of the threshold voltage signal end, the first switching transistor that is turned on makes the control end and the output end of the drive module switch on, low level is inputted into the reference signal end, and the process of resetting the control end and the output end of the drive module is performed;

in the compensation phase, high level is inputted into the reference signal end, and the first switching transistor is still in a turning-on state, the first switching transistor that is turned on makes the control end and the output end of the drive module switch on, and the reference voltage of the control end and the input end of the drive module is compensated.

4. The pixel circuit according to claim 3, wherein the first switching transistor is a P-type transistor.

5. The pixel circuit according to claim 1, the charge control module comprises:

a second switching transistor;

the gate of the second switching transistor is connected with the scan signal end, the source thereof is connected with the data signal end, and the drain thereof is connected with the first input end of the reset control module.

6. The pixel circuit according to claim 5, wherein, in the reset and compensation phase, the second switching transistor is turned on under the control of the scan signal end, the second switching transistor that is turned on makes the data signal end and the first input end of the reset control module switch on and then writes the data signal inputted by the data signal end to the first input end of the reset control module;

in the data writing phase, the second switching transistor is still in the turning-on state, the second switching transistor that is turned on writes the reference voltage signal inputted by the data signal end to the first input end of the reset control module.

7. The pixel circuit according to claim 6, wherein the second switching transistor is a P-type transistor.

8. The pixel circuit according to claim 1, the drive module comprises:

a drive transistor;

the gate of the drive transistor is connected with the first output end of the reset control module, the source thereof is connected with the reference signal end, and the drain thereof is connected with the second output end of the reset control module and the input end of the light-emitting control module.

9. The pixel circuit according to claim 8, wherein, in the reset phase, low level signal is inputted in the reference signal end which resets the gate of the drive transistor to ensure that the drive transistor is in the turning-on state in the compensation phase to implement the compensation process.

10. The pixel circuit according to claim 9, wherein the drive transistor is a P-type transistor.

11. The pixel circuit according to claim 1, the light-emitting control module comprises:

a third switching transistor;

the gate of the third switching transistor is connected with the light-emitting signal end, the source thereof is connected with the output end of the drive module and the second output end of the reset control module, and the drain thereof is connected with the input end of the light emitting device.

12. The pixel circuit according to claim 11, wherein, in the light-emitting phase, the third switching transistor is turned on under the control of the light-emitting signal end, the third switching transistor that is turned on makes the output end of the drive module and the input end of the light emitting device switch on, which enables the drive module to drive the light emitting device to realize the normal luminescence function in the light-emitting phase.

13. The pixel circuit according to claim 12, wherein the third switching transistor is a P-type transistor.

14. An organic electroluminescent display panel, comprising a pixel circuit, the pixel circuit comprises:

a charge control module, a drive module, a reset control module, a light-emitting control module and a light emitting device;

wherein

a control end of the charge control module is connected with a scan signal end, an input end thereof is connected with a data signal end, and an output end thereof is connected with the first input end of the reset control module;

a control end of the reset control module is connected with a threshold voltage signal end, the second input end is connected with a reference signal end and an input end of the drive module, respectively, the first output end is connected with a control end of the drive module, and the second output end is connected with an output end of the drive module and an input end of the light-emitting control module, respectively;

a control end of the light-emitting control module is connected with a light-emitting signal end, an output end thereof is connected with an input end of the light emitting device; and

an output end of the light emitting device is connected with a low level signal end;

in the reset and compensation phase, the charge control module makes the data signal end and the first input end of the reset control module switch on under the control of the scan signal end;

the reset control module resets the control end and the output end of the drive module and compensates reference voltage under the control of the threshold voltage signal end and the reference signal end;

in the data writing phase, the charge control module writes the data signal inputted by the data signal end to the first input end of the reset control module under the control of the scan signal end;

in the light-emitting phase, the light-emitting control module makes the output end of the drive module and the input end of the light emitting device switch on to drive the light emitting device to emit light under the control of the light-emitting signal end.

16. The organic electroluminescent display panel according to claim 14, the reset control module comprises:

a first capacitor, a second capacitor, and a first switching transistor;

wherein

the gate of the first switching transistor is connected with a threshold voltage signal end, the source thereof is connected with a control end of the drive module, and the drain thereof is connected with an output end of the drive module and an input end of the light-emitting control module, respectively;

the first capacitor is connected between an output end of the charge control module and a control end of the drive module;

and the second capacitor is connected between the reference signal end and the control end of the drive module.

17. The organic electroluminescent display panel according to claim 14, the charge control module comprises:

a second switching transistor;

the gate of the second switching transistor is connected with the scan signal end, the source thereof is connected with the data signal end, and the drain thereof is connected with the first input end of the reset control module.

18. The organic electroluminescent display panel according to claim 14, the drive module comprises:

a drive transistor,

the gate of the drive transistor is connected with the first output end of the reset control module, the source thereof is connected with the reference signal end, and the drain thereof is connected with the second output end of the reset control module and the input end of the light-emitting control module.

19. The organic electroluminescent display panel according to claim 14, the light-emitting control module comprises:

a third switching transistor,

the gate of the third switching transistor is connected with the light-emitting signal end, the source thereof is connected with the output end of the drive module and the second output end of the reset control module, and the drain thereof is connected with the input end of the light emitting device.

20. A display device, comprising the organic electroluminescent display panel according to claim 14.

15. (canceled)