Pixel circuit and driving method thereof, display apparatus

Patent metadata

Field	Value
Publication number	US-2016133187-A1
Application number	US-201314345480-A
Country	US
Kind code	A1
Filing date	May 4, 2013
Priority date	Mar 21, 2013
Publication date	May 12, 2016
Grant date	—

Abstract

A pixel circuit and driving method thereof, display apparatus, the pixel circuit comprises: light-emitting device; driving transistor (DTFT); first switch-transistor (T 1 ) whose source is connected with the gate of the driving transistor (DTFT), and drain is connected with the drain of the driving transistor (DTFT); third switch-transistor (T 3 ), whose drain is connected with the light-emitting device, source is connected with the drain of the driving transistor (DTFT); storage capacitor (Cst), whose first terminal (G) is connected with the gate of the driving transistor (DTFT); second switch-transistor (T 2 ), whose drain is connected with the second terminal (P) of the storage capacitor (Cst), and source is connected with the common connection terminal (VSS); fourth switch-transistor (T 4 ), whose source is connected with the second terminal (P) of the storage capacitor; fifth switch-transistor (T 5 ), whose drain is connected with data signal terminal (Vdata), and source is connected with the drain of the fourth switch-transistor (T 4 ); and first capacitor (C 1 ), whose first terminal is connected with the source of the fifth switch-transistor (T 5 ), and second terminal is connected with the common connection terminal (VSS). In the above pixel circuit, current flowing through the driving transistor and the light-emitting device is not affected by threshold voltage of the driving transistor by compensation for the driving transistor so that luminance of the light-emitting device is uniform.

First claim

1 . A pixel circuit comprising:
a light-emitting device, one terminal thereof is connected with a supply voltage terminal; a driving transistor for driving the light-emitting device, whose source is connected with a common connection terminal; a first switch transistor, whose gate receives a first scan signal, source is connected with a gate of the driving transistor, and drain is connected with a drain of the driving transistor; a third switch transistor, whose drain is connected with the other terminal of the light-emitting device, source is connected with the drain of the driving transistor, and gate is connected with a control signal; a storage capacitor, whose first terminal is connected with the gate of the driving transistor; a second switch transistor, whose drain is connected with a second terminal of the storage capacitor, and source is connected with the common connection terminal; a fourth switch transistor, whose gate is connected with the first scan signal, and source is connected with the second terminal of the storage capacitor; a fifth switch transistor, whose gate is connected with the control signal, drain is connected with a data signal terminal, and source is connected with a drain of the fourth switch transistor; and a first capacitor, whose first terminal is connected with the source of the fifth switch transistor, and second terminal is connected with the common connection terminal.

2 . The pixel circuit of claim 1 , wherein the first switch transistor, the second switch transistor, the third switch transistor, the fourth switch transistor, the fifth switch transistor and the driving transistor are all thin film field effect transistors.

3 . The pixel circuit of claim 2 , wherein the first switch transistor, the second switch transistor, the third switch transistor and the driving transistor have the same channel type, and the channel types of the fourth switch transistor and the fifth switch transistor are opposite to those of the first switch transistor, the second switch transistor, the third switch transistor and the driving transistor.

4 . The pixel circuit of claim 3 , wherein the first switch transistor, the second switch transistor, the third switch transistor and the driving transistor are N-type thin film field effect transistors, and the fourth switch transistor and the fifth switch transistor are P-type thin film field effect transistors.

5 . The pixel circuit of claim 1 , wherein the common connection terminal is a ground terminal.

6 . The pixel circuit of claim 1 , wherein the light-emitting device is an organic light-emitting diode.

7 . A display apparatus comprising the pixel circuit of claim 1 .

8 . A driving method for the pixel circuit of claim 1 , comprising:
during a first stage, the first switch transistor, the second switch transistor and the fifth switch transistor are turned on, the third switch transistor and the fourth switch transistor are turned off, the gate and the drain of the driving transistor are connected, the driving transistor is saturated, and the storage capacitor discharges through its first terminal; during a second stage, the first switch transistor, the second switch transistor and the third switch transistor are turned off, the fourth switch transistor and the fifth switch transistor are turned on, the storage capacitor and the first capacitor are charged, the voltage at the second terminal of the storage capacitor raises consequently, and the driving transistor is turned on; and during a third stage, the first switch transistor, the second switch transistor and the fifth switch transistor are turned off, the third switch transistor and the fourth switch transistor are turned on, the first capacitor holds the voltage at the first terminal of the storage capacitor while the driving transistor continues being in a turn-on state, a supply voltage signal drives the light-emitting device to emit lights through the driving transistor.

9 . The display apparatus of claim 7 , wherein the first switch transistor, the second switch transistor, the third switch transistor, the fourth switch transistor, the fifth switch transistor and the driving transistor are all thin film field effect transistors.

10 . The display apparatus of claim 9 , wherein the first switch transistor, the second switch transistor, the third switch transistor and the driving transistor have the same channel type, and the channel types of the fourth switch transistor and the fifth switch transistor are opposite to those of the first switch transistor, the second switch transistor the third switch transistor and the driving transistor.

11 . The display apparatus of claim 10 , wherein the first switch transistor, the second switch transistor, the third switch transistor and the driving transistor are N-type thin film field effect transistors, and the fourth switch transistor and the fifth switch transistor are P-type thin film field effect transistors.

12 . The display apparatus of claim 7 , wherein the common connection terminal is a ground terminal.

13 . The display apparatus of claim 7 , wherein the light-emitting device is an organic light-emitting diode.

Assignees

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

Inventors

• Li Tianma
• Li Hongwei
• Han Jing

Classifications

• G09G2300/0852

  being a dynamic memory with more than one capacitor · CPC title

• G09G2300/0819

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

• G09G2330/021

  Power management, e.g. power saving · CPC title

• G09G3/3233 Primary

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

• G09G3/3258 Primary

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