Pixel circuit and driving method thereof, and display panel

• US 10,978,002 B2
• Filed: 06/27/2019
• Issued: 04/13/2021
• Est. Priority Date: 06/29/2018
• Status: Active Grant

• Current Assignee: BOE Technology Group Co., Ltd.
• Original Assignee: BOE Technology Group Co., Ltd.
• Inventors: Yue, Han, Xuan, Minghua
• Primary Examiner(s): Bolotin, Dmitriy
• Application Number:
  US16/632,989
• Publication Number:
  US 20200211464A1
• Time in Patent Office: 656 Days
• CPC Class Codes: G09G 2300/0814 used for selection purposes, e.g. logical AND for partial update
• CPC Class Codes: G09G 2300/0819 used for counteracting undesired variations, e.g. feedback or autozeroing
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/0861 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 Class Codes: G09G 2310/0262 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 Class Codes: G09G 2310/027 Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
• CPC Class Codes: G09G 2310/061 for resetting or blanking
• CPC Class Codes: G09G 3/32 semiconductive, e.g. using light-emitting diodes [LED]
• CPC Class Codes: G09G 3/3225 using an active matrix
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3258 with pixel circuitry controlling the voltage across the light-emitting element
• CPC Class Codes: G09G 3/3266 Details of drivers for scan electrodes

Abstract

Disclosed are a pixel circuit, a driving method thereof, and a display panel. The pixel circuit includes a driving circuit, a data writing circuit, a storage circuit, a light emitting circuit and a grayscale regulation circuit. The driving circuit includes a control terminal, a first terminal and a second terminal, and is configured to control a driving current; the data writing circuit is configured to write a data signal into the control terminal of the driving circuit; the storage circuit is configured to store the data signal; one terminal of the grayscale regulation circuit is connected with the second terminal of the driving circuit, another terminal thereof is connected with a first terminal of the light emitting circuit, and the grayscale regulation circuit is configured to regulate a voltage of the first terminal of the light emitting circuit according to the data signal in response to a switch driving signal.

Claims

1. A pixel circuit, comprising:

a driving circuit, a data writing circuit, a storage circuit and a grayscale regulation circuit,

wherein the driving circuit comprises a control terminal, a first terminal and a second terminal, and is configured to control a driving current flowing through the first terminal and the second terminal and used to drive a light emitting circuit to emit light, the first terminal of the driving circuit is configured to receive a first voltage from a first voltage terminal;

the data writing circuit is connected with the control terminal of the driving circuit and is configured to write a data signal into the control terminal of the driving circuit;

the storage circuit is connected with the control terminal of the driving circuit and is configured to store the data signal written by the data writing circuit; and

one terminal of the grayscale regulation circuit is connected with the second terminal of the driving circuit, another terminal of the grayscale regulation circuit is connected with a first terminal of the light emitting circuit, and the grayscale regulation circuit is configured to have a first cross voltage in a case where the light emitting circuit displays a first grayscale and to have a second cross voltage in a case where the light emitting circuit displays a second grayscale, so as to regulate a voltage of the first terminal of the light emitting circuit according to the data signal in response to a switch driving signal, wherein the first grayscale is less than the second grayscale, and the first cross voltage is greater than the second cross voltage.

2. The pixel circuit according to claim 1, wherein the light emitting circuit comprises a plurality of light emitting elements connected in series.

3. The pixel circuit according to claim 1, wherein the driving circuit comprises a first transistor,

a gate electrode of the first transistor serves as the control terminal of the driving circuit, a first electrode of the first transistor serves as the first terminal of the driving circuit and is configured to be connected to the first voltage terminal to receive the first voltage, and a second electrode of the first transistor serves as the second terminal of the driving circuit.

4. The pixel circuit according to claim 1, wherein the data writing circuit comprises a second transistor and a third transistor;

a gate electrode of the second transistor is connected with a first scan line to receive a first scan signal, a first electrode of the second transistor is connected with a data line to receive the data signal, and a second electrode of the second transistor is connected with the control terminal of the driving circuit; and

a gate electrode of the third transistor is connected with a second scan line to receive a second scan signal, a first electrode of the third transistor is connected with the data line to receive the data signal, and a second electrode of the third transistor is connected with the control terminal of the driving circuit.

5. The pixel circuit according to claim 1, wherein the data writing circuit comprises a second transistor or a third transistor;

a gate electrode of the second transistor is connected with a first scan line to receive a first scan signal, a first electrode of the second transistor is connected with a data line to receive the data signal, and a second electrode of the second transistor is connected with the control terminal of the driving circuit; and

a gate electrode of the third transistor is connected with a second scan line to receive a second scan signal, a first electrode of the third transistor is connected with the data line to receive the data signal, and a second electrode of the third transistor is connected with the control terminal of the driving circuit.

6. The pixel circuit according to claim 1, wherein the storage circuit comprises a storage capacitor,

a first electrode of the storage capacitor is connected with the control terminal of the driving circuit, and a second electrode of the storage capacitor is connected with a third voltage terminal to receive a third voltage.

7. The pixel circuit according to claim 1, wherein the grayscale regulation circuit comprises a fourth transistor,

a gate electrode of the fourth transistor is connected with a switch driving signal line to receive the switch driving signal, a first electrode of the fourth transistor is connected to the second terminal of the driving circuit, and a second electrode of the fourth transistor is connected to the first terminal of the light emitting circuit.

8. The pixel circuit according to claim 1, further comprising a reset circuit, wherein the reset circuit is connected with a reset voltage terminal and the first terminal of the light emitting circuit, and is configured to apply a reset voltage to the first terminal of the light emitting circuit.

9. The pixel circuit according to claim 8, wherein the reset circuit comprises a fifth transistor,

a gate electrode of the fifth transistor is connected with a reset control line to receive a reset signal, a first electrode of the fifth transistor is connected with the reset voltage terminal to receive the reset voltage, and a second electrode of the fifth transistor is connected with the first terminal of the light emitting circuit.

10. A display panel, comprising a plurality of pixel units arranged in an array,

wherein each of the plurality of pixel units comprises the light emitting circuit and the pixel circuit according to claim 8.

11. A display panel, comprising a plurality of pixel units arranged in an array,

wherein each of the plurality of pixel units comprises the light emitting circuit and the pixel circuit according to claim 1.

12. The display panel according to claim 11, wherein the light emitting circuit comprises the first terminal and a second terminal, and

the second terminal of the light emitting circuit is configured to receive a second voltage from a second voltage terminal.

13. A driving method of pixel circuit, wherein the pixel circuit comprises a driving circuit, a data writing circuit, a storage circuit and a grayscale regulation circuit,

the driving circuit comprises a control terminal, a first terminal and a second terminal, and is configured to control a driving current flowing through the first terminal and the second terminal and used to drive a light emitting circuit to emit light, the first terminal of the driving circuit is configured to receive a first voltage from a first voltage terminal;

the data writing circuit is connected with the control terminal of the driving circuit and is configured to write a data signal into the control terminal of the driving circuit;

the storage circuit is connected with the control terminal of the driving circuit and is configured to store the data signal written by the data writing circuit; and

one terminal of the grayscale regulation circuit is connected with the second terminal of the driving circuit, another terminal of the grayscale regulation circuit is connected with a first terminal of the light emitting circuit, and the grayscale regulation circuit is configured to have a first cross voltage in a case where the light emitting circuit displays a first grayscale and to have a second cross voltage in a case where the light emitting circuit displays a second grayscale, so as to regulate a voltage of the first terminal of the light emitting circuit according to the data signal in response to a switch driving signal, wherein the first grayscale is less than the second grayscale, and the first cross voltage is greater than the second cross voltage; and

the driving method comprises a light emitting stage;

in the light emitting stage, input the switch driving signal to turn on the grayscale regulation circuit, so that the grayscale regulation circuit has a first cross voltage in a case where the light emitting circuit displays a first grayscale, and has a second cross voltage in a case where the light emitting circuit displays a second grayscale, thereby controlling the driving current flowing through the light emitting circuit according to the data signal and applying the driving current to the light emitting circuit,

wherein the first grayscale is less than the second grayscale, and the first cross voltage is greater than the second cross voltage.

14. The driving method of the pixel circuit according to claim 13, wherein the grayscale regulation circuit comprises a transistor,

the transistor operates in a saturation region in a case where the light emitting circuit displays the first grayscale, and the transistor operates in a linear region in a case where the light emitting circuit displays the second grayscale.

15. The driving method of the pixel circuit according to claim 13, further comprising:

in the light emitting stage, inputting the data signal, a first scan signal and a second scan signal to turn on the data writing circuit and the driving circuit, so that the data writing circuit writes the data signal into the driving circuit, and the storage circuit stores the data signal.

16. The driving method of the pixel circuit claim 13, further comprising an initialization stage in a case where the pixel circuit comprises a reset circuit,

wherein in the initialization stage, input a reset signal to turn on the reset circuit, so that a reset voltage is applied to the first terminal of the light emitting circuit.