Pixel circuit having dual-gate transistor, and driving method and display thereof

Patent metadata

Field	Value
Publication number	US-10796625-B2
Application number	US-201815984808-A
Country	US
Kind code	B2
Filing date	May 21, 2018
Priority date	May 23, 2017
Publication date	Oct 6, 2020
Grant date	Oct 6, 2020

Abstract

The present disclosure discloses a pixel circuit, a driving method and a display, including: a compensation unit connected with a driving unit; an external power supply, a driving unit and a first light emitting unit sequentially connected in series; a capacitor disposed between a first node and the external power supply; and an initialization unit with a first initialization transistor having a first electrode of connected to the first node, a gate electrode externally connected to a second scan signal, and a second electrode connected to a second light emitting unit, and a second initialization transistor having a first electrode connected to the second light emitting unit, a second electrode connected to an initialization voltage and a gate electrode externally connected to a second scan signal. The first initialization transistor and the second initialization transistor are a dual-gate transistor.

First claim

What is claimed is:

1. A pixel circuit, comprising: a compensation unit, a driving unit, a first light emitting unit, a second light emitting unit, an initialization unit, a capacitor, and an external power supply;
wherein the compensation unit is electrically connected to the driving unit through a first node; the external power supply, the driving unit, and the first light emitting unit are sequentially connected in series; the capacitor is disposed between the first node and the external power supply; the initialization unit comprises a first initialization transistor and a second initialization transistor, a first electrode of the first initialization transistor is electrically connected to the first node, and a gate electrode of the first initialization transistor is externally connected to a second scan signal, a second electrode of the first initialization transistor is electrically connected to the second light emitting unit, a first electrode of the second initialization transistor is electrically connected to the second light emitting unit, a second electrode of the second initialization transistor is externally connected to an initialization voltage, a gate electrode of the second initialization transistor is externally connected to the second scan signal, the first initialization transistor and the second initialization transistor are a dual-gate transistor;
the compensation unit is externally connected to the data signal and a first scan signal, and the compensation unit is configured to, under the effect of the first scan signal, set the
voltage of the first node to a first voltage which is resulted from the voltage of the data signal being compensated by a compensation transistor in the compensation unit;
the capacitor is configured to maintain the voltage of the first node at the first voltage;
the driving unit is externally connected to a first control signal, the driving unit is configured to generate a driving current to drive the light emitting unit to emit light according to the first control signal, the driving current is obtained according to the first voltage, an external power supply and a threshold voltage of a driving transistor in the driving unit, and the driving transistor and the compensation transistor are a common-gate transistor; and
the initialization unit is configured to turn on the first initialization transistor and the second initialization transistor under the control of the second scan signal, and initialize the first node and the second light emitting unit with the initialization voltage,
wherein the compensation unit comprises a data strobe transistor, a compensation transistor and a switch transistor;
a first electrode of the data strobe transistor is electrically connected to a second electrode of the compensation transistor, a second electrode of the data strobe transistor is externally connected to the data signal, a gate electrode of the data strobe transistor is externally connected to the first scan signal, a first electrode of the compensation transistor is electrically connected to a gate electrode of the compensation transistor, and a gate electrode of the compensation transistor is electrically connected to the driving unit through the first node;
a first electrode of the switch transistor is electrically connected to a gate electrode of the compensation transistor and a gate electrode of the driving transistor, a second electrode of the switch transistor is electrically connected to a first electrode of the compensation transistor, and a gate electrode of the switch transistor is externally connected to the first scan signal, and the switch transistor is configured to turn on or turn off the compensation transistor according to the first scan signal;
the compensation unit is configured to turn on the data strobe transistor through the first scan signal, so that the compensation transistor sets the voltage of the first node to the first voltage which is resulted from the voltage of the data signal being compensated by a compensation transistor in the compensation unit.

2. The pixel circuit of claim 1 , wherein the driving transistor and the compensation transistor are mirror transistors.

3. The pixel circuit of claim 1 , wherein
the second light emitting unit is a first light emitting unit of an adjacent pixel circuit.

4. A pixel circuit driving method applied to the pixel circuit according to claim 1 , comprising:
in an initialization stage, controlling the second scan signal to turn on the first initialization transistor and the second initialization transistor, the first initialization transistor initializing the first node with the initialization voltage, the second initialization transistor initializing the second light emitting unit with the initialization voltage, the capacitor maintaining the initialization voltage, controlling the first scan signal to turn off the compensation unit and controlling the first control signal to turn off the driving unit;
in a data writing stage, controlling the first scan signal to turn on the compensation unit, and the compensation unit setting the voltage of the first node to the first voltage; controlling the first control signal to turn off the driving unit, so that the first light emitting unit does not emit light, controlling the second scan signal to turn off the first initialization transistor and the second initialization transistor; the capacitor maintaining the voltage of the first node at the first voltage; wherein, the first voltage is resulted from the voltage of the data signal being compensated by the compensation transistor in the compensation unit;
in a light emitting stage, controlling the first scan signal to turn off the compensation unit; controlling the second scan signal to turn off the first initialization transistor and the second initialization transistor, and controlling the first control signal to turn on the driving unit, the driving unit generating a driving current to drive the first light emitting unit to emit light; wherein the driving current is obtained based on the first voltage, the external power supply, and the threshold voltage of the driving transistor in the driving unit; and the capacitor is in the maintaining state.

5. The method of claim 4 , wherein controlling the first scan signal to turn on the compensation unit comprises:
controlling the first scan signal to turn on the data strobe transistor or the switch transistor.

6. A display comprising a pixel circuit according to claim 1 .

7. The display of claim 6 , wherein the driving transistor and the compensation transistor are mirror transistors.

8. The display of claim 6 , wherein
the second light emitting unit is a first light emitting unit of an adjacent pixel circuit.

Assignees

• Everdisplay Optronics Shanghai Ltd

Inventors

• Zhou Xingyu

Classifications

• G09G3/3233 Primary

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

• G09G2310/0251

  Precharge or discharge of pixel before applying new pixel voltage · CPC title

• G09G2320/043

  Preventing or counteracting the effects of ageing · CPC title

• G09G2310/0262

  The addressing of the pixel, in a display other than an active matrix LCD, involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependent on signals of two data electrodes · CPC title

• G09G2300/0861

  with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes · CPC title