Pixel circuit and method for driving a light emitting device and organic light emitting display panel

Patent metadata

Field	Value
Publication number	US-10325553-B2
Application number	US-201514786005-A
Country	US
Kind code	B2
Filing date	Jan 12, 2015
Priority date	Sep 25, 2014
Publication date	Jun 18, 2019
Grant date	Jun 18, 2019

Abstract

There are provided a pixel circuit, a method for driving the light emitting device ( 04 ) and an organic light emitting display panel. The initializing module ( 03 ) is added to the pixel circuit. In the initializing phase, the initializing module ( 03 ) initializes the driving module ( 02 ) and the light emitting device ( 04 ); in the writing phase, the charging module ( 01 ) writes the data signal inputted from the data signal terminal into the control terminal of the driving module ( 02 ); and in the light emitting phase, the charging module ( 01 ) loads the first reference signal inputted from the data signal terminal (Data) to the control terminal of the driving module ( 02 ), and the initializing module ( 03 ) connects the output terminal of the driving module ( 02 ) with the input terminal of the light emitting device ( 04 ) so that the driving module ( 02 ) drives the light emitting device ( 04 ) to emit light. The pixel circuit initializes the driving module ( 02 ) and the light emitting device ( 04 ) in the initialization phase, which eliminates the influence of the voltage difference in a previous phase on a subsequent phase, provides a compensating voltage and a driving voltage for the driving module ( 02 ) in the writing phase, which avoids the influence of change of the threshold voltage on the light emitting luminance of the light emitting device ( 04 ), so that the quality of the display picture is ensured.

First claim

What is claimed is:

1. A pixel circuit, comprising a light emitting device, and further comprising:
a charging module, whose input terminal is connected to a data signal terminal and control terminal is connected to a scanning signal terminal;
a driving module, whose input terminal is connected to a first reference signal terminal and control terminal is connected to an output terminal of the charging module; and
an initializing module, wherein the initializing module comprises a reset unit and a control unit, a control terminal of the reset unit is connected to an initializing signal terminal, a first output terminal thereof is connected to the control terminal of the driving module and the output terminal of the charging module respectively, a first input terminal thereof is directly connected to an output terminal of the driving module and an output terminal of the control unit respectively, a second output terminal thereof is directly connected to an input terminal of the control unit and the input terminal of the light emitting device, and a second input terminal thereof is directly connected to the output terminal of the light emitting device and a second reference signal terminal, a control terminal of the control unit is connected to a control signal terminal;
wherein in an initializing phase, the initializing module is configured to initialize the driving module and the light emitting device under the control of the initializing signal terminal and the control signal terminal; in a writing phase, the charging module is configured to write a data signal inputted from the data signal terminal into the control terminal of the driving module under the control of the scanning signal terminal; and in a light emitting phase, the charging module is configured to load a first reference signal inputted from the data signal terminal to the control terminal of the driving module under the control of the scanning signal terminal, and the initializing module is configured to connect the output terminal of the driving module with the input terminal of the light emitting device under the control of the control signal terminal so that the driving module drives the light emitting device to emit light.

2. The pixel circuit according to claim 1 , wherein the driving module comprises a driving transistor and a storage capacitor;
a gate of the driving transistor is connected to the output terminal of the charging module and the first output terminal of the initializing module, a source thereof is connected to the first reference signal terminal, and a drain thereof is connected to the first input terminal of the initializing module; and
the storage capacitor is connected between the gate and the drain of the driving transistor.

3. The pixel circuit according to claim 2 , wherein
a control terminal of the reset unit is connected to the initializing signal terminal, a first output terminal thereof is connected to the output terminal of the charging module and the gate of the driving transistor respectively, a first input terminal thereof is connected to the drain of the driving transistor and an output terminal of the control unit respectively;
in the initializing phase, the reset unit connects the gate and the drain of the driving transistor under the control of the initialization signal terminal, and connects the input terminal of the light emitting device with the second reference signal terminal; the control unit connects the drain of the driving transistor with the second output terminal of the reset unit under the control of the control signal terminal; and
in the light emitting phase, the control unit connects the drain of the driving transistor with the input terminal of the light emitting device under the control of the control signal terminal.

4. The pixel circuit according to claim 3 , wherein the reset unit comprises a first switching transistor and a second switching transistor;
a gate of the first switching transistor is connected to the initializing signal terminal, a drain thereof is connected to the output terminal of the charging module and the control terminal of the driving transistor respectively, and a source thereof is connected to the drain of the driving transistor and the output terminal of the control unit respectively; and
a gate of the second switching transistor is connected to the initializing signal terminal, a drain thereof is connected to the input terminal of the control unit and the input terminal of the light emitting device respectively, and a source thereof is connected to the output terminal of the light emitting device and the second reference signal terminal respectively.

5. The pixel circuit according to claim 4 , wherein the charging module comprises a fourth switching transistor;
a gate of the fourth switching transistor is connected to the scanning signal terminal, a source thereof is connected to the data signal terminal, and a drain thereof is connected to the drain of the first switching transistor and the gate of the driving transistor respectively.

6. The pixel circuit according to claim 3 , wherein the control unit comprises a third switching transistor;
a gate of the third switching transistor is connected to the control signal terminal, a drain thereof is connected to the drain of the driving transistor and the source of the first switching transistor respectively, and a source thereof is connected to the drain of the second switching transistor and the input terminal of the light emitting device.

7. The pixel circuit according to claim 6 , wherein the charging module comprises a fourth switching transistor;
a gate of the fourth switching transistor is connected to the scanning signal terminal, a source thereof is connected to the data signal terminal, and a drain thereof is connected to the drain of the first switching transistor and the gate of the driving transistor respectively.

8. The pixel circuit according to claim 3 , wherein the charging module comprises a fourth switching transistor;
a gate of the fourth switching transistor is connected to the scanning signal terminal, a source thereof is connected to the data signal terminal, and a drain thereof is connected to the drain of the first switching transistor and the gate of the driving transistor respectively.

9. The pixel circuit according to claim 2 , wherein in the writing phase, the charging module is configured to write a threshold voltage of the driving transistor into the storage capacitor before writing the data signal into the control terminal of the driving module.

10. The pixel circuit according to claim 9 , wherein the initializing module comprises a reset unit and a control unit;
a control terminal of the reset unit is connected to the initializing signal terminal, a first output terminal thereof is connected to the output terminal of the charging module and the gate of the driving transistor respectively, a first input terminal thereof is connected to the drain of the driving transistor and an output terminal of the control unit respectively, a second output terminal thereof is connected to an input terminal of the control terminal and the input terminal of the light emitting device, and a second input terminal thereof is connected to the output terminal of the light emitting device and the second reference signal terminal;
a control terminal of the control unit is connected to the control signal terminal;
in the initializing phase, the reset unit connects the gate and the drain of the driving transistor under the control of the initialization signal terminal, and connects the input terminal of the light emitting device with the second reference signal terminal; the control unit connects the drain

Assignees

• Boe Technology Group Co Ltd
• Hefei Xinsheng Optoelectronics Technology Co Ltd

Inventors

• Hu Zuquan

Classifications

• G09G3/3291

  in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting elements · CPC title

• G09G2320/0233

  Improving the luminance or brightness uniformity across the screen · CPC title

• G09G2320/045

  Compensation of drifts in the characteristics of light emitting or modulating elements · CPC title

• G09G2310/08

  Details of timing specific for flat panels, other than clock recovery · CPC title

• G09G2300/0842

  forming a memory circuit, e.g. a dynamic memory with one capacitor · CPC title