Pixel circuit integrating threshold voltage compensation with touch detection, driving method thereof, and organic light-emitting display panel

Patent metadata

Field	Value
Publication number	US-9367164-B2
Application number	US-201314355461-A
Country	US
Kind code	B2
Filing date	Sep 10, 2013
Priority date	May 31, 2013
Publication date	Jun 14, 2016
Grant date	Jun 14, 2016

Abstract

Embodiments of the present disclosure provide a pixel circuit, a driving method thereof, an organic light-emitting display panel and a display device. The pixel circuit is provided with a touch sensing module, a driving transistor, a driving control module and a light-emitting module. The pixel circuit compensates for a threshold voltage of the driving transistor by a diode connection of the driving transistor and a discharging of a storage capacitor, so that a driving current of the driving transistor is independent of the threshold voltage of the driving transistor, and thus the driving currents of the OLEDs located at different positions on the organic light-emitting display panel are consistent, which can improve a brightness uniformity and a reliability of the display panel.

First claim

What is claimed is:

1. A pixel circuit comprising a driving transistor, a driving control circuit and a light-emitting circuit, wherein
the driving transistor is connected with the driving control circuit and the light-emitting circuit, respectively;
the driving control circuit is connected with an input terminal for a first level signal, an input terminal for a second level signal, an input terminal for a first timing control signal, an input terminal for a second timing control signal, an input terminal for a third timing control signal, an input terminal for a second timing control signal of a previous stage of a pixel circuit, an input terminal for a second timing control signal of a next stage of a pixel circuit, the driving transistor and the light-emitting circuit, respectively, and is configured to compensate for a threshold voltage of the driving transistor and control the driving transistor to drive the light-emitting circuit to emit light under control of timing control signals as inputted; and
the light-emitting circuit is connected with the input terminal for the third timing control signal, the input terminal for the second level signal, the driving transistor and the driving control circuit, respectively, and is configured to emit light as driven by the driving transistor, under the control of the inputted timing control signal;
wherein the pixel circuit further comprises a touch sensing circuit, wherein the touch sensing circuit is connected with the input terminal for the first level signal, the input terminal for the second timing control signal of the previous stage of the pixel circuit and a node A, and is configured to detect a touch signal on a touch screen under a control of the second timing control signal of the previous stage of the pixel circuit;
wherein the driving control circuit comprises a fifth transistor, wherein a drain of the fifth transistor is connected with a data line, and a gate of the fifth transistor is connected with the input terminal for the second timing control signal, a source of the fifth transistor is connected to the source of the driving transistor;
the fifth transistors is turned on during a touch detecting phase so as to transmit a voltage variation at the node A due to a touch on a touch screen to the data line, and is turned on during a compensating phase to write a data voltage to the source of the driving transistor.

2. The pixel circuit of claim 1 , wherein the touch sensing circuit comprises:
a sensing element and a seventh transistor;
a first terminal of the sensing element is connected with the input terminal for the first level signal, and a second terminal of the sensing element is connected with a source of the seventh transistor; and
a gate of the seventh transistor is connected with the input terminal for the second timing control signal of the previous stage of the pixel circuit, and a drain of the seventh transistor is connected with the node A.

3. The pixel circuit of claim 1 , wherein the sensing element is a photodiode, the first terminal of the sensing element is a cathode of the photodiode, and the second terminal of the sensing element is an anode of the photodiode; or
the sensing element is a touch capacitor, and the first terminal and the second terminal of the sensing element are two terminals of the touch capacitor respectively.

4. The pixel circuit of claim 2 , wherein the driving control circuit further comprises:
a first transistor, a second transistor, a fourth transistor, an eighth transistor and a storage capacitor;
a source of the first transistor is connected with the input terminal for the second level signal, a gate of the first transistor is connected with the input terminal for the first timing control signal, and a drain of the first transistor is connected with the node A;
a source of the second transistor is connected with a drain of the eighth transistor, a drain of the driving transistor and the light-emitting circuit, respectively; a gate of the second transistor is connected with the input terminal for the second timing control signal of the next stage of the pixel circuit, and a drain of the second transistor is connected with the node A;
a source of the fourth transistor is connected with a first terminal of the storage capacitor and the input terminal for the first level signal, respectively; a gate of the fourth transistor is connected with the input terminal for the third timing control signal, and a drain of the fourth transistor is connected with a drain of the fifth transistor and a source of the driving transistor, respectively;
a source of the eighth transistor is connected with the input terminal for the second level signal, and a gate of the eighth transistor is connected with the input terminal for the second timing control signal of the previous stage of the pixel circuit; and
a second terminal of the storage capacitor is connected with the node A.

5. The pixel circuit of claim 4 , wherein the light-emitting circuit comprises:
a third transistor and an organic light-emitting diode;
a source of the third transistor is connected with the source of the second transistor, the drain of the driving transistor, the drain of the eighth transistor, respectively, a gate of the third transistor is connected with the input terminal for the third timing control signal, and a drain of the third transistor is connected with an anode of the organic light-emitting diode; and
a cathode of the organic light-emitting diode is connected with the input terminal for the second level signal.

6. The pixel circuit of claim 5 , wherein the gate of the driving transistor is connected with the node A.

7. The pixel circuit of claim 6 , wherein all of the driving transistor, the first transistor, the second transistor, the third transistor, the fourth transistor, the fifth transistor, the seventh transistor and the eighth transistor are P-type transistors;
the input terminal for the first level signal is connected with a high level; and
the input terminal for the second level signal is connected with a low level.

8. A driving method for driving a pixel circuit comprising a driving transistor, a driving control circuit, a light-emitting circuit and a touch sensing circuit, wherein the driving control circuit comprises a first transistor, a second transistor, a fourth transistor, a fifth transistor, an eighth transistor and a storage capacitor;
wherein a drain of the first transistor is connected with an input terminal for a second level signal, a gate of the first transistor is connected with an input terminal for a first timing control signal, and a source of the first transistor is connected with a node A;
a gate of the driving transistor is connected to the node A;
a source of the second transistor is connected with the node A, a gate of the second transistor is connected with an input terminal for a second timing control signal of a next stage of the pixel circuit, and a drain of the second transistor is connected with the drain of the driving transistor;
a source of the fourth transistor is connected with an input terminal for a first level signal, a gate of the fourth transistor is connected with an input terminal for a third timing control signal, and a drain of the fourth transistor is connected with a source of the driving transistor;
a drain of the fifth transistor is connected with a data line, and a gate of the fifth transistor is connected with an input terminal for a second timing control signal, and a source of the fifth transistor is connected to the source of the driving transistor;
a source of the eighth transistor is connected with the drain of the driving transistor, a gate the eighth transistor is connected with an input terminal for

Assignees

• Boe Technology Group Co Ltd
• Chengdu Boe Optoelect Tech Co

Inventors

• Wu Bo
• Qi Xiaojing
• Nie Leisen

Classifications

• G09G3/3258

  with pixel circuitry controlling the voltage across the light-emitting element · CPC title

• G09G2310/0272

  Details of drivers for data electrodes, the drivers communicating data to the pixels by means of a current · CPC title

• G09G2320/0653

  Controlling or limiting the speed of brightness adjustment of the illumination source · CPC title

• G09G2300/0819

  used for counteracting undesired variations, e.g. feedback or autozeroing · CPC title

• G09G2320/0233

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