PIXEL CIRCUIT, DRIVING METHOD AND DISPLAY APPARATUS

• US 20170154576A1
• Filed: 03/30/2015
• Published: 06/01/2017
• Est. Priority Date: 11/11/2014
• Status: Active Grant

• Current Assignee: BOE Technology Group Co., Ltd.
• Original Assignee: BOE Technology Group Co., Ltd.
• Inventors: Sun, Tuo
• Granted Patent: US 9,734,763 B2
• Time in Patent Office: Days
• CPC Class Codes: G09G 2300/043 Compensation electrodes or other additional electrodes in matrix displays related to distortions or compensation signals, e.g. for modifying TFT threshold voltage in column driver
• CPC Class Codes: G09G 2300/0452 Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
• CPC Class Codes: G09G 2300/0465 Improved aperture ratio, e.g. by size reduction of the pixel circuit, e.g. for improving the pixel density or the maximum displayable luminance or brightness
• CPC Class Codes: G09G 2300/0809 Several active elements per pixel in active matrix panels
• 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 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 3/2074 using sub-pixels
• 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 3/3291 in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting elements

Abstract

The embodiments of the present disclosure disclose a pixel circuit, a driving method and a display apparatus. The pixel circuit comprises multiple sub-pixel circuits, one of which is arranged with a threshold compensation module, and shares a voltage compensated by the threshold compensation module with other sub-pixel circuits. According to the embodiments of the present disclosure, only a threshold compensation module may be arranged for multiple pixels, so as to reduce an average area occupied by a single pixel and is beneficial for improving the PPI of the display apparatus.

Claims

1. A pixel circuit, comprising:

a first sub-pixel circuit, comprising a driving transistor for generating driving current, a capacitor for pulling up a gate voltage of the driving transistor and a threshold compensation module, wherein the threshold compensation module is connected to the capacitor in the first sub-pixel circuit to compensate for a threshold voltage of the driving transistor in the first sub-pixel circuit for the capacitor;

at least one second sub-pixel circuit, comprising a driving transistor for generating driving current and a capacitor for pulling up a gate voltage of the corresponding driving transistor; and

a compensation sharing circuit having a first end connected to the capacitor of the first sub- pixel circuit and a second end connected to the capacitor of the at least one second sub-pixel circuit, wherein the compensation sharing circuit is configured to turn on the first end and the second end under the control of an input control signal, so that the threshold compensation module compensates for a threshold voltage for the capacitor of the at least one second sub-pixel circuit while compensating for the threshold voltage for the capacitor of the first sub-pixel circuit.

2. The pixel circuit according to claim 1, wherein the compensation sharing circuit comprises a sharing control transistor having one of a source and a drain connected to a first end of the capacitor in the first sub-pixel circuit, and the other connected to a first end of the capacitor in the at least one second sub-pixel circuit.

3. The pixel circuit according to claim 2, wherein each of the sub-pixel circuits comprises a writing control transistor connected between a second end of a corresponding capacitor and a data voltage input end of a respective sub-pixel circuit.

4. The pixel circuit according to claim 3, wherein each of the sub-pixel circuits comprises at least one resetting control transistor connected to a capacitor of a corresponding sub-pixel circuit to reset the capacitor of the corresponding sub-pixel circuit.

5. The pixel circuit according to claim 4, wherein a driving transistor of each sub-pixel circuit is a p-channel transistor, and each sub-pixel circuit further comprises a light-emitting control transistor connected between a drain of a corresponding driving transistor and an electroluminescent element;

the threshold compensation module comprises a compensation control transistor having one of a source and a drain connected to a drain of the driving transistor of the first sub-pixel circuit, and the other connected to the first end of the capacitor in the first sub-pixel circuit; and

in the first sub-pixel circuit, a gate of the driving transistor is connected to the first end of the capacitor, in the at least one second sub-pixel circuit, a gate of the driving transistor is connected to a second end of the capacitor, and the drain of the at least one resetting control transistor is connected to a first end of a corresponding capacitor.

6. The pixel circuit according to claim 5, wherein a gate of the writing control transistor in the first sub-pixel circuit is connected to a first control signal input end of the pixel circuit;

gates of the writing control transistor and the resetting control transistor in the at least one second sub-pixel circuit are connected to a second control signal input end;

gates of the compensation control transistor and the sharing control transistor are connected to a third control signal input end of the pixel circuit;

gates of various light-emitting control transistors are connected to a fourth control signal input end; and

various transistors of which gates are connected to the same input end have the same channel type.

7. The pixel circuit according to claim 6, wherein the first sub-pixel circuit further comprises a jumping control transistor connected between the source of the driving transistor of the first sub-pixel circuit and the second end of the capacitor and has a gate connected to the third control signal input end;

and the first control signal input end and the third control signal input end are the same input end.

8. The pixel circuit according to claim 3, wherein a driving transistor in each sub-pixel circuit is a P-channel transistor having a gate connected to a first end of a corresponding capacitor;

and

each sub-pixel circuit further comprises a light-emitting control transistor connected between a drain of the driving transistor and an electroluminescent element, the threshold compensation module comprises a compensation control transistor having one of a source and a drain connected to the drain of the driving transistor in the first sub-pixel circuit and the other connected to the first end of the capacitor in the first sub-pixel circuit.

9. The pixel circuit according to claim 3, wherein a driving transistor in each sub-pixel circuit is an N-channel transistor, and has a gate connected to a first end of a capacitor of a corresponding sub-pixel circuit;

each sub-pixel circuit further comprises a light-emitting control transistor connected between a drain of a corresponding driving transistor and an electroluminescent element;

the threshold compensation module further comprises a compensation control transistor having one of a source and a drain connected to the source of the driving transistor in the first sub-pixel circuit and the other connected to the ground; and

the first sub-pixel circuit further comprises a charging control transistor having one of a source and a drain connected to the first end of the capacitor in the first sub-pixel circuit.

10. The pixel circuit according to claim 9, wherein the other of the source and drain of the charging control transistor is connected to a working voltage input end of the pixel circuit.

11. A method for driving the pixel circuit according to any one of claims 1-10, comprising:

applying a control signal to turn on a first end and a second end of the compensation sharing circuit when the first sub-pixel circuit implements pixel compensation.

12. A display apparatus, comprising the pixel circuit according to claim 1.

13. A display apparatus, comprising the pixel circuit according to claim 2.

14. A display apparatus, comprising the pixel circuit according to claim 3.

15. A display apparatus, comprising the pixel circuit according to claim 4.

16. A display apparatus, comprising the pixel circuit according to claim 5.

17. A display apparatus, comprising the pixel circuit according to claim 6.

18. A display apparatus, comprising the pixel circuit according to claim 7.

19. A display apparatus, comprising the pixel circuit according to claim 8.

20. A display apparatus, comprising the pixel circuit according to claim 9.