Pixel circuit, driving method for the pixel circuit, display panel, and display device

• US 9,972,245 B2
• Filed: 10/24/2016
• Issued: 05/15/2018
• Est. Priority Date: 01/05/2016
• Status: Active Grant

• Current Assignee: BOE Technology Group Co., Ltd.
• Original Assignee: BOE Technology Group Co., Ltd.
• Inventors: Wang, Lirong
• Primary Examiner(s): Zheng, Xuemei
• Application Number:
  US15/540,113
• Publication Number:
  US 20180005570A1
• Time in Patent Office: 568 Days
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2300/0814 used for selection purposes, e.g. logical AND for partial update
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/0866 by means of changes in the pixel supply voltage
• CPC Class Codes: G09G 2310/0243 Details of the generation of driving signals
• 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 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/045 Compensation of drifts in the characteristics of light emitting or modulating elements
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/32 semiconductive, e.g. using light-emitting diodes [LED]
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element

Abstract

A pixel circuit, a driving method for the pixel circuit, a display panel, and a display device, the pixel circuit includes a selecting module (01), a writing module (02), a driving module (03), and a light emitting element (OLED). When a high-luminance picture needs to be displayed, the selecting module (01) outputs the signal from the first power supply signal terminal (VDDH) to the second node (P2), so that the signal from the first power supply signal terminal (VDDH) drives the light emitting element (OLED) to emit light; when a low-luminance picture is to be displayed, the selecting module (01) outputs a signal from the second power supply signal terminal (VDDL) to the second node (P2), so that the signal from the second power source signal (VDDL) drives the light emitting element to emit light.

Claims

1. A pixel circuit, comprising a selecting module, a writing module, a driving module, and a light emitting element, wherein

a first control terminal of the selecting module is connected with a first node, a first input terminal of the selecting module is connected with a first power supply signal terminal, a second control terminal and a second input terminal of the selecting module are connected with a second power supply signal terminal, and an output terminal of the selecting module is connected with a second node;

the selecting module is configured to select a signal from the first power supply signal terminal or a signal from the second power supply signal terminal and to output the selected signal to the second node under control of the first node and the second power supply signal terminal;

a control terminal of the driving module is connected with the first node, an input terminal of the driving module is connected with the second node, and an output terminal of the driving module is connected with an input terminal of the light emitting element;

the driving module is configured to drive, under control of the first node, the light emitting element to emit light according to a signal inputted from the second node, the signal inputted from the second node corresponds to the signal from the first power supply signal terminal or the signal from the second power supply signal terminal;

an output terminal of the light emitting element is connected with a third power supply signal terminal;

a first control terminal of the writing module is configured to receive a first control signal, a second control terminal of the writing module is configured to receive a second control signal, a first input terminal of the writing module is connected with a data signal terminal, a second input terminal of the writing module is connected with a reference signal terminal, a first output terminal of the writing module is connected with the first node, and a second output terminal of the writing module is connected with the input terminal of the light emitting element;

the writing module is configured to write a signal from the data signal terminal to the first node under control of the first control signal, and to initialize, under control of the second control signal, the input terminal of the light emitting element by a signal inputted from the reference signal terminal.

2. The pixel circuit according to claim 1, wherein the selecting module comprises a first switching transistor and a second switching transistor;

a gate of the first switching transistor is connected with the first node, a drain of the first switching transistor is connected with the first power supply signal terminal, and a source of the first switching transistor is connected with the second node;

a gate and a source of the second switching transistor are connected with the second power supply signal terminal, and a drain of the second switching transistor is connected with the second node.

3. The pixel circuit according to claim 1, wherein the writing module comprises a data writing unit and an initializing unit;

a control terminal of the data writing unit is configured to receive the first control signal, an input terminal of the data writing unit is connected with the data signal terminal, and an output terminal of the data writing unit is connected with the first node;

the data writing unit is configured to write a signal from the data signal terminal to the first node under control of the first control signal;

a control terminal of the initializing unit is configured to receive the second control signal, an input terminal of the initializing unit is connected with the reference signal terminal, and an output terminal of the initializing unit is connected with the input terminal of the light emitting element;

the initializing unit is configured to initialize, under control of the second control signal, the input terminal of the light emitting element by a signal inputted from the reference signal terminal.

4. The pixel circuit according to claim 3, wherein the data writing unit comprises a third switching transistor;

a gate of the third switching transistor is configured to receive the first control signal, a source of the third switching transistor is connected with the data signal terminal, and a drain of the third switching transistor is connected with the first node.

5. The pixel circuit according to claim 3, wherein the initializing unit comprises a fourth switching transistor;

a gate of the fourth switching transistor is configured to receive the second control signal, a source of the fourth switching transistor is connected with the reference signal terminal, and a drain of the fourth switching transistor is connected with the input terminal of the light emitting element.

6. The pixel circuit according to claim 1, wherein the driving module comprises a fifth switching transistor and a capacitor;

a gate of the fifth switching transistor is connected with the first node, a drain of the fifth switching transistor is connected with the second node, and a source of the fifth switching transistor is connected with the input terminal of the light emitting element;

the capacitor is connected between the first node and the input terminal of the light emitting element.

7. A driving method for the pixel circuit according to claim 1, comprising:

in a writing period, by the writing module, writing a signal from the data signal terminal to the first node under control of the first control signal, and initializing, under control of the second control signal, the input terminal of the light emitting element by a signal inputted from the reference signal terminal;

in a light emitting period, outputting, by the selecting module, a signal from the first power supply signal terminal or a signal from the second power supply signal terminal to the second node under control of the first node and the second power supply signal terminal, and driving, by the driving module, under control of the first node, the light emitting element to emit light according to a signal inputted from the second node, the signal inputted from the second node corresponds to the signal from the first power supply signal terminal or the signal from the second power supply signal terminal.

8. A display panel, comprising the pixel circuit according to claim 1.

9. A display device, comprising the display panel according to claim 8.

10. The display device according to claim 9, wherein the selecting module comprises a first switching transistor and a second switching transistor;

a gate of the first switching transistor is connected with the first node, a drain of the first switching transistor is connected with the first power supply signal terminal, and a source of the first switching transistor is connected with the second node;

a gate and a source of the second switching transistor are connected with the second power supply signal terminal, and a drain of the second switching transistor is connected with the second node.

11. The display device according to claim 9, wherein the writing module comprises a data writing unit and an initializing unit;

a control terminal of the data writing unit is configured to receive the first control signal, an input terminal of the data writing unit is connected with the data signal terminal, and an output terminal of the data writing unit is connected with the first node;

the data writing unit is configured to write a signal from the data signal terminal to the first node under control of the first control signal;

a control terminal of the initializing unit is configured to receive the second control signal, an input terminal of the initializing unit is connected with the reference signal terminal, and an output terminal of the initializing unit is connected with the input terminal of the light emitting element;

the initializing unit is configured to initialize, under control of the second control signal, the input terminal of the light emitting element by a signal inputted from the reference signal terminal.

12. The display device according to claim 11, wherein the data writing unit comprises a third switching transistor;

a gate of the third switching transistor is configured to receive the first control signal, a source of the third switching transistor is connected with the data signal terminal, and a drain of the third switching transistor is connected with the first node.

13. The display device according to claim 11, wherein the initializing unit comprises a fourth switching transistor;

a gate of the fourth switching transistor is configured to receive the second control signal, a source of the fourth switching transistor is connected with the reference signal terminal, and a drain of the fourth switching transistor is connected with the input terminal of the light emitting element.

14. The display device according to claim 9, wherein the driving module comprises a fifth switching transistor and a capacitor;

a gate of the fifth switching transistor is connected with the first node, a drain of the fifth switching transistor is connected with the second node, and a source of the fifth switching transistor is connected with the input terminal of the light emitting element;

the capacitor is connected between the first node and the input terminal of the light emitting element.

15. The display panel according to claim 8, wherein the selecting module comprises a first switching transistor and a second switching transistor;

a gate of the first switching transistor is connected with the first node, a drain of the first switching transistor is connected with the first power supply signal terminal, and a source of the first switching transistor is connected with the second node;

a gate and a source of the second switching transistor are connected with the second power supply signal terminal, and a drain of the second switching transistor is connected with the second node.

16. The display panel according to claim 8, wherein the writing module comprises a data writing unit and an initializing unit;

a control terminal of the data writing unit is configured to receive the first control signal, an input terminal of the data writing unit is connected with the data signal terminal, and an output terminal of the data writing unit is connected with the first node;

the data writing unit is configured to write a signal from the data signal terminal to the first node under control of the first control signal;

a control terminal of the initializing unit is configured to receive the second control signal, an input terminal of the initializing unit is connected with the reference signal terminal, and an output terminal of the initializing unit is connected with the input terminal of the light emitting element;

the initializing unit is configured to initialize, under control of the second control signal, the input terminal of the light emitting element by a signal inputted from the reference signal terminal.

17. The display panel according to claim 16, wherein the data writing unit comprises a third switching transistor;

a gate of the third switching transistor is configured to receive the first control signal, a source of the third switching transistor is connected with the data signal terminal, and a drain of the third switching transistor is connected with the first node.

18. The display panel according to claim 16, wherein the initializing unit comprises a fourth switching transistor;

a gate of the fourth switching transistor is configured to receive the second control signal, a source of the fourth switching transistor is connected with the reference signal terminal, and a drain of the fourth switching transistor is connected with the input terminal of the light emitting element.

19. The display panel according to claim 8, wherein the driving module comprises a fifth switching transistor and a capacitor;

a gate of the fifth switching transistor is connected with the first node, a drain of the fifth switching transistor is connected with the second node, and a source of the fifth switching transistor is connected with the input terminal of the light emitting element;

the capacitor is connected between the first node and the input terminal of the light emitting element.