Pixel circuit, display panel, display device and driving method

Patent metadata

Field	Value
Publication number	US-10692434-B2
Application number	US-201715569243-A
Country	US
Kind code	B2
Filing date	Apr 7, 2017
Priority date	Aug 22, 2016
Publication date	Jun 23, 2020
Grant date	Jun 23, 2020

Abstract

A pixel circuit, a display panel, a display device and a driving method. The pixel circuit includes a storage capacitor, an organic light emitting diode, a driving transistor, an emission control circuit, a reset circuit, a threshold compensation circuit, a first data write circuit, a reference voltage write circuit, and an initializing circuit.

First claim

What is claimed is:

1. A pixel circuit, comprising:
a storage capacitor including a first end connected with a first node and a second end connected with a second node;
an organic light-emitting diode (OLED) including a first electrode connected with a third node;
a driving transistor including a gate electrode connected with the first node, wherein the driving transistor is configured to control the OLED to emit light according to a voltage of the first node;
an emission control circuit configured to receive an emission control signal and control an on/off state of the OLED according to the emission control signal;
a reset circuit configured to receive a reset control signal and write a reset voltage into the first node according to the reset control signal;
a threshold compensation circuit configured to receive a first scanning signal and write a compensating voltage into the first node according to the first scanning signal, wherein the compensating voltage is a sum of a first supply voltage and a threshold voltage of the driving transistor;
a first data write circuit configured to receive the first scanning signal and a data signal and write the data signal into the second node according to the first scanning signal;
a reference voltage write circuit configured to receive a second scanning signal and write a reference voltage into the second node according to the second scanning signal; and
an initializing circuit configured to receive the first scanning signal and write an initializing voltage into the third node according to the first scanning signal,
wherein the initializing circuit is controlled by the first scanning signal, the reset circuit is controlled by the reset control signal, and the first scanning signal is different from the reset control signal;
the reference voltage is different from the first supply voltage, and is different from the initializing voltage;
wherein in a reset period within a display period of one frame, the emission control signal is set to be a turn-off voltage; the reset control signal is set to be a turn-on voltage; the first scanning signal is set to be a turn-off voltage; the second scanning signal is set to be a turn-on voltage; the data signal is set to be an ineffective data signal, the emission control circuit is configured to be turned off under control of the emission control signal to control to turn off a connection between the OLED and the driving transistor, the reset circuit is configured to be turned on under control of the reset control signal to write the reset voltage into the first node, the threshold compensation circuit is configured to be turned off under control of the first scanning signal, the first data write circuit is configured to be turned off under control of the first scanning signal, the reference voltage write circuit is configured to be turned on under control of the second scanning signal to write the reference voltage into the second node, and the initializing circuit is configured to be turned off under control of the first scanning signal;
in a data write and threshold compensation period within the display period of one frame, the emission control signal is set to be a turn-off voltage; the reset control signal is set to be a turn-off voltage; the first scanning signal is set to be a turn-on voltage; the second scanning signal is set to be a turn-off voltage; the data signal is set to be an effective data signal, the emission control circuit is configured to be turned off under control of the emission control signal to control to turn off the connection between the OLED and the driving transistor, the reset circuit is configured to be turned off under control of the reset control signal, the threshold compensation circuit is configured to be turned on under control of the first scanning signal to write the compensation voltage into the first node, the first data write circuit is configured to be turned on under control of the first scanning signal to write the effective data signal into the second node, the reference voltage write circuit is configured to be turned off under control of the second scanning signal, and the initializing circuit is configured to be turned on under control of the first scanning signal to write the initializing voltage into the third node;
in a voltage drop compensation period within the display period of one frame, the emission control signal is set to be a turn-off voltage; the reset control signal is set to be a turn-off voltage; the first scanning signal is set to be a turn-off voltage; the second scanning signal is set to be a turn-on voltage; the data signal is set to be an ineffective data signal, the emission control circuit is configured to be turned off under control of the emission control signal to control to turn off the connection between the OLED and the driving transistor, the reset circuit is configured to be turned off under control of the reset control signal, the threshold compensation circuit is configured to be turned off under control of the first scanning signal, the first data write circuit is configured to be turned off under control of the first scanning signal, the reference voltage write circuit is configured to be turned on under control of the second scanning signal to write the reference voltage into the second node, and the initializing circuit is configured to be turned off under control of the first scanning signal; and
in an emission period within the display period of one frame, the emission control signal is set to be a turn-on voltage; the reset control signal is set to be a turn-off voltage; the first scanning signal is set to be a turn-off voltage; the second scanning signal is set to be a turn-on voltage; and the data signal is set to be an ineffective data signal, the emission control circuit is configured to be turned on under control of the emission control signal to control the OLED to emit light, the reset circuit is configured to be turned off under control of the reset control signal, the threshold compensation circuit is configured to be turned off under control of the first scanning signal, the first data write circuit is configured to be turned off under control of the first scanning signal, the reference voltage write circuit is configured to be turned on under control of the second scanning signal to write the reference voltage into the second node, and the initializing circuit is configured to be turned off under control of the first scanning signal.

2. The pixel circuit according to claim 1 , wherein the initializing voltage is equal to the reset voltage.

3. The pixel circuit according to claim 1 , wherein the OLED further includes a second electrode;
the second electrode of the OLED is electrically connected with a second power line to receive a second supply voltage;
the first electrode of the OLED is an anode; the second electrode of the OLED is a cathode; and
difference between the initializing voltage and the second supply voltage is less than a cut-in voltage of the OLED.

4. The pixel circuit according to claim 3 , wherein the initializing voltage is less than the second supply voltage.

5. The pixel circuit according to claim 1 , wherein the reset circuit includes a first transistor;
the threshold compensation circuit includes a second transistor;
the first data write circuit includes a third transistor;
the reference voltage write circuit includes a fourth transistor;
the emission control circuit includes a fifth transistor; and
the initializing circuit includes a sixth transistor.

6. The pixel circuit according to claim 5 , wherein
a gate electrode of the driving transistor is electrically connected with the first node; a first electrode of the driving transistor is electrically connected with a first power line to

Assignees

• Boe Technology Group Co Ltd
• Ordos Yuansheng Optoelectronics Co Ltd

Inventors

• Zhang Yi
• Zhang Kai
• Xuan Minghua
• Ko Young Yik
• Huangfu Lujiang

Classifications

• G09G3/3233 Primary

  with pixel circuitry controlling the current through the light-emitting element · CPC title

• G09G3/3275

  Details of drivers for data electrodes · CPC title

• G09G3/3266

  Details of drivers for scan electrodes · 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