Pixel circuit, display panel and drive method for a pixel circuit

Patent metadata

Field	Value
Publication number	US-10733939-B2
Application number	US-201815890361-A
Country	US
Kind code	B2
Filing date	Feb 7, 2018
Priority date	Aug 15, 2017
Publication date	Aug 4, 2020
Grant date	Aug 4, 2020

Abstract

Disclosed are a pixel circuit, a display panel and a drive method for a pixel circuit. The pixel circuit comprises: a light-emitting element, configured for emitting light in response to a drive current; a drive transistor, configured for providing the drive current to the light-emitting element; a data write device, configured for writing a data signal to a gate electrode of the drive transistor; a hold device, electrically connected with the gate electrode of the drive transistor and configured for holding a voltage on the gate electrode of the drive transistor in a light-emitting stage; and a control device, electrically connected with the gate electrode of the drive transistor and configured for controlling the drive transistor to operate in a full cut-off region in a cut-off stage, wherein, the cut-off stage precedes the light-emitting stage.

First claim

What is claimed is:

1. A pixel circuit, comprising:
a light-emitting element, which is configured for emitting light in response to a drive current;
a drive transistor, which is configured for providing the drive current to the light-emitting element;
a first transistor, a gate electrode of the first transistor is electrically connected with a first scan line, a first terminal of the first transistor is electrically connected with a data line, and a second terminal of the first transistor is electrically connected with the first electrode of the drive transistor;
a first capacitor, which is configured for holding a voltage on the gate electrode of the drive transistor in a light-emitting stage, wherein a first electrode of the first capacitor is electrically connected with the gate electrode of the drive transistor, and a second electrode of the first capacitor is directly electrically connected with a first level signal line;
a third transistor, which is configured for controlling the drive transistor to operate in a full cut-off region in a cut-off stage, wherein the cut-off stage precedes the light-emitting stage, and wherein a first electrode of the third transistor is electrically connected with one of a third level signal line and a second light-emitting signal line, a second electrode of the third transistor is electrically connected with the gate electrode of the drive transistor through a first node, and a gate electrode of the third transistor is electrically connected with a control signal line;
a fourth transistor, wherein a control terminal of the fourth transistor is electrically connected with a first light-emitting signal line, a first terminal of the fourth transistor is electrically connected with the first level signal line, and a second terminal of the fourth transistor is electrically connected with a first electrode of the drive transistor;
a fifth transistor, wherein a control terminal of the fifth transistor is electrically connected with the first light-emitting signal line, a first terminal of the fifth transistor is electrically connected with a second electrode of the drive transistor, and a second terminal of the fifth transistor is electrically connected with a first electrode of the light-emitting element; and
a sixth transistor, wherein a control terminal of the six transistor is electrically connected with a second scan line, a first terminal of the six transistor is electrically connected with a fourth level signal line, and a second terminal of the six transistor is electrically connected with the gate electrode of the drive transistor and the first electrode of the first capacitor through the first node;
wherein in the cut-off stage, the fourth transistor and the fifth transistor are turned on under control of a logic low-level first light-emitting signal from the first light-emitting signal line so that a logic high-level signal from the first level signal line is written to the first electrode of the drive transistor, the third transistor is turned on under control of a logic low-level control signal from the control signal line so that a logic high-level signal from the third level signal line is written to the gate electrode of the drive transistor through the first node, and the drive transistor is configured to be worked in the full cut-off region.

2. The pixel circuit as claimed in claim 1 , wherein, the drive transistor is one of an N-type transistor and a P-type transistor;
wherein in order to control the drive transistor to operate in the full cut-off region in the cut-off stage,
if the drive transistor is the N-type transistor, a voltage difference between the gate electrode and a source electrode of the drive transistor is smaller than a negative value of the threshold voltage thereof; and
if the drive transistor is the P-type transistor, the voltage difference between the gate electrode and the source electrode of the drive transistor is larger than the negative value of the threshold voltage thereof.

3. The pixel circuit as claimed in claim 1 , further comprising: a second transistor;
wherein a gate electrode of the second transistor is electrically connected with the first scan line, a first terminal of the second transistor is electrically connected with a second electrode of the drive transistor, and a second terminal of the second transistor is electrically connected with the gate electrode of the drive transistor; and
wherein a second electrode of the light-emitting element is electrically connected with a second level signal line.

4. The pixel circuit as claimed in claim 1 , wherein, a voltage value of a signal on the third level signal line is larger than a voltage value of a signal on the first level signal line.

5. The pixel circuit as claimed in claim 1 , wherein
signals on the first light-emitting signal line and the second light-emitting signal line are both impulse signals; and
the signal on the second light-emitting signal line is a signal immediately preceding to the signal on the first light-emitting signal line.

6. The pixel circuit as claimed in claim 5 , wherein
the signal on the second light-emitting signal line is an impulse signal; and
a voltage value of a high-level signal on the second light-emitting signal line is larger than a voltage value of the signal on the first level signal line.

7. The pixel circuit as claimed in claim 3 , wherein
signals on the control signal line, the first scan line and the second scan line are all impulse signals; and
the signal on the second scan line is a signal immediately preceding to the signal on the first scan line.

8. The pixel circuit as claimed in claim 7 , wherein, the gate electrode of the third transistor is electrically connected with a third scan line, the signal on the third scan line is an impulse signal, and the signal on the third scan line is a signal immediately preceding to the signal on the second scan line, and the third scan line is reused as the control signal line.

9. The pixel circuit as claimed in claim 3 , wherein
the first transistor, the second transistor, the third transistor, the fourth transistor, the fifth transistor, the sixth transistor and the drive transistor are all P-type transistors.

10. The pixel circuit as claimed in claim 3 , further comprising: an eighth transistor, wherein
a first electrode of the eighth transistor is electrically connected with the fourth level signal line, a second electrode of the eighth transistor is electrically connected with the first electrode of the light-emitting element, and a gate electrode of the eighth transistor is electrically connected with the second scan line.

11. A display panel, comprising:
a pixel circuit, wherein the pixel circuit comprises:
a light-emitting element, which is configured for emitting light in response to a drive current;
a drive transistor, which is configured for providing the drive current to the light-emitting element;
a first transistor, a gate electrode of the first transistor is electrically connected with a first scan line, a first terminal of the first transistor is electrically connected with a data line, and a second terminal of the first transistor is electrically connected with the first electrode of the drive transistor;
a first capacitor, which is configured for holding a voltage on the gate electrode of the drive transistor in a light-emitting stage, wherein a first electrode of the first capacitor is electrically connected with the gate electrode of the drive transistor, and a second electrode of the first capacitor is directly electrically connected with a first level signal line;
a third transistor, which is configured for controlling the drive t

Assignees

• Shanghai Tianma Am Oled Co Ltd

Inventors

• Xi Kerui
• Ouyang Junting
• Lin Baiquan
• Cui Tingting

Classifications

• G09G3/3233 Primary

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

• G09G2300/0814

  used for selection purposes, e.g. logical AND for partial update · CPC title

• G09G2300/0842

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

• G09G2300/0819

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

• G09G3/3258

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