Pixel circuit, display panel, and driving method

• US 10,565,932 B2
• Filed: 12/05/2017
• Issued: 02/18/2020
• Est. Priority Date: 03/17/2017
• Status: Active Grant

• Current Assignee: BOE Technology Group Co., Ltd., Ordos Yuansheng Optoelectronics Co., Ltd. (BOE Technology Group Co., Ltd.)
• Original Assignee: BOE Technology Group Co., Ltd.
• Inventors: Zhang, Yi
• Primary Examiner(s): Dharia, Prabodh M
• Application Number:
  US15/764,995
• Publication Number:
  US 20190043426A1
• Time in Patent Office: 805 Days
• Field of Search: 345 82, 345205, 345212, 345504, 345760
• CPC Class Codes: G09G 2230/00 Details of flat display driving waveforms
• CPC Class Codes: G09G 2300/0417 Special arrangements specific to the use of low carrier mobility technology
• CPC Class Codes: G09G 2300/0819 used for counteracting undesired variations, e.g. feedback or autozeroing
• CPC Class Codes: G09G 2300/0876 Supplementary capacities in pixels having special driving circuits and electrodes instead of being connected to common electrode or ground; Use of additional capacitively coupled compensation electrodes
• CPC Class Codes: G09G 2310/0213 controlling the sequence of the scanning lines with respect to the patterns to be displayed, e.g. to save power
• CPC Class Codes: G09G 2310/0216 Interleaved control phases for different scan lines in the same sub-field, e.g. initialization, addressing and sustaining in plasma displays that are not simultaneous for all scan lines
• CPC Class Codes: G09G 2310/0264 Details of driving circuits
• 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 2330/023 using energy recovery or conservation
• 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

Abstract

A pixel circuit includes a driving sub-circuit, a compensation sub-circuit, a data writing sub-circuit, and a data voltage storage sub-circuit. The driving sub-circuit includes a first electrode electrically coupled to a high voltage input terminal and a second electrode configured to output a driving current. The compensation sub-circuit is configured to store a threshold voltage of the driving sub-circuit. The compensation sub-circuit includes a first terminal electrically coupled to the second electrode of the driving sub-circuit, a second terminal electrically coupled to a gate electrode of the driving sub-circuit, a third terminal, and a fourth terminal, and a control terminal. The data writing sub-circuit includes a first terminal and a second terminal. The data voltage storage sub-circuit includes a first terminal electrically coupled to the third terminal of the compensation sub-circuit and the second terminal of the data writing sub-circuit; and a second terminal.

Claims

1. A pixel circuit, comprising:

a driving sub-circuit including a first electrode electrically coupled to a high voltage input terminal and a second electrode configured to output a driving current;

a compensation sub-circuit including;

a first terminal electrically coupled to the second electrode of the driving sub-circuit;

a second terminal electrically coupled to a gate electrode of the driving sub-circuit;

a third terminal;

a fourth terminal electrically coupled to a fixed voltage terminal; and

a control terminal,

the compensation sub-circuit being configured to;

store a threshold voltage of the driving sub-circuit, and

in response to a compensation control signal received at the control terminal, electrically link the fourth terminal of the compensation sub-circuit to the third terminal of the compensation sub-circuit and electrically link the first terminal of the compensation sub-circuit to the second terminal of the compensation sub-circuit;

a data writing sub-circuit including a first terminal, a second terminal, and a control terminal, the data writing sub-circuit being configured to;

in response to a data writing control signal received at the control terminal of the data writing sub-circuit, electrically link the first terminal of the data writing sub-circuit to the second terminal of the data writing sub-circuit;

a data voltage storage sub-circuit configured to store a data voltage inputted through the data writing sub-circuit, the data voltage storage sub-circuit including;

a first terminal electrically coupled to the third terminal of the compensation sub-circuit and the second terminal of the data writing sub-circuit; and

a second terminal electrically coupled to the high voltage input terminal; and

an initialization sub-circuit including a first terminal electrically coupled to the fixed voltage terminal, a second terminal electrically coupled to the third terminal of the compensation sub-circuit, a third terminal electrically coupled to the second terminal of the compensation sub-circuit, a fourth terminal electrically coupled to a reference voltage input terminal, and a control terminal,

wherein the initialization sub-circuit is configured to, in response to an initialization control signal received at the control terminal of the initialization sub-circuit, electrically link the second terminal of the initialization sub-circuit to the first terminal of the initialization sub-circuit and electrically link the third terminal of the initialization sub-circuit to the fourth terminal of the initialization sub-circuit.

2. The pixel circuit according to claim 1, wherein:

the data voltage storage sub-circuit includes a data voltage storage capacitor,

the second terminal of the data voltage storage sub-circuit includes a first electrode plate of the data voltage storage capacitor, and

the first terminal of the data voltage storage sub-circuit includes a second electrode of the data voltage storage capacitor.

3. The pixel circuit according to claim 1, wherein the compensation sub-circuit includes:

a compensation capacitor including a first electrode plate and a second electrode plate;

a first compensation transistor including a first electrode, a second electrode electrically coupled to the first electrode plate of the compensation capacitor, and a gate electrode; and

a second compensation transistor including a first electrode, a second electrode, and a gate electrode electrically coupled to the gate electrode of the first compensation transistor,

wherein;

the first terminal of the compensation sub-circuit includes the second electrode of the second compensation transistor,

the second terminal of the compensation sub-circuit includes the second electrode plate of the compensation capacitor and the first electrode of the second compensation transistor,

the third terminal of the compensation sub-circuit includes the first electrode plate of the compensation capacitor,

the fourth terminal of the compensation sub-circuit includes the first electrode of the first compensation transistor, and

the control terminal of the compensation sub-circuit includes the gate electrode of the first compensation transistor.

4. The pixel circuit according to claim 1, wherein:

the data writing sub-circuit includes a data writing transistor,

the first terminal of the data writing sub-circuit includes a first electrode of the data writing transistor electrically coupled to a data signal input terminal,

the second terminal of the data writing sub-circuit includes a second electrode of the data writing transistor, and

the control terminal of the data writing sub-circuit includes a gate electrode of the data writing transistor.

5. The pixel circuit according to claim 1, further comprising:

a light-emitting sub-circuit coupled to the second electrode of the driving sub-circuit and configured to emit light in response to the driving current.

6. The pixel circuit according to claim 5, further comprising:

a light emission control sub-circuit including a first terminal electrically coupled to the second electrode of the driving sub-circuit, a second terminal electrically coupled to a first terminal of the light-emitting sub-circuit, and a control terminal,

wherein the light emission control sub-circuit is configured to, in response to a light emission control signal received at the control terminal of the light emission control sub-circuit, electrically link the second electrode of the driving sub-circuit to the first terminal of the light-emitting sub-circuit.

7. The pixel circuit according to claim 6, wherein:

the light emission control sub-circuit includes a light emission control transistor,

the first terminal of the light emission control sub-circuit includes a first electrode of the light emission control transistor,

the second terminal of the light emission control sub-circuit includes a second electrode of the light emission control transistor, and

the control terminal of the light emission control sub-circuit includes a gate electrode of the light emission control transistor.

8. The pixel circuit according to claim 5, further comprising:

a discharge sub-circuit including a first terminal electrically coupled to a reference voltage input terminal, a second terminal electrically coupled to a first terminal of the light-emitting sub-circuit, and a control terminal,

wherein;

the discharge sub-circuit is configured to, in response to a discharge control signal received at the control terminal of the discharge sub-circuit, electrically link the first terminal of the discharge sub-circuit to the second terminal of the discharge sub-circuit, and

the control terminal of the discharge sub-circuit is electrically coupled to the control terminal of the compensation sub-circuit.

9. The pixel circuit according to claim 8, wherein:

the discharge sub-circuit includes a discharge transistor,

the first terminal of the discharge sub-circuit includes a first electrode of the discharge transistor,

the second terminal of the discharge sub-circuit includes a second electrode of the discharge transistor, and

the control terminal of the discharge sub-circuit includes a gate electrode of the discharge transistor.

10. The pixel circuit according to claim 1, wherein:

the initialization sub-circuit includes a first initialization transistor and a second initialization transistor,

the fourth terminal of the initialization sub-circuit includes a first electrode of the first initialization transistor,

the third terminal of the initialization sub-circuit includes a second electrode of the first initialization transistor,

the control terminal of the initialization sub-circuit includes a gate electrode of the first initialization transistor,

the first terminal of the initialization sub-circuit includes a first electrode of the second initialization transistor,

the second terminal of the initialization sub-circuit includes a second electrode of the second initialization transistor, and

a gate electrode of the second initialization transistor is electrically coupled to the gate electrode of the first initialization transistor.

11. The pixel circuit according to claim 1, wherein the fixed voltage terminal includes a reference voltage input terminal.

12. The pixel circuit according to claim 1, wherein the fixed voltage terminal includes the high voltage input terminal.

13. A display panel, comprising:

a plurality of pixel units each including a pixel circuit according to claim 1;

a plurality of data lines electrically coupled to data signal input terminals; and

a plurality of sets of gate lines,

wherein each one of the sets of gate lines is coupled to the pixel circuit of one of the pixel units and includes;

a compensation control gate line electrically coupled to the control terminal of the compensation sub-circuit of the pixel circuit;

a data writing control gate line electrically coupled to the control terminal of the data writing sub-circuit of the pixel circuit; and

an initialization control gate line electrically coupled to a control terminal of an initialization sub-circuit of the pixel circuit.

14. The display panel according to claim 13, wherein:

each one of the sets of gate lines further include a light emission control gate line electrically coupled to a control terminal of a light emission control sub-circuit of the pixel circuit.

15. A driving method for a display panel according to claim 13, comprising:

at a compensation phase of a duty cycle, providing a compensation control signal to the compensation control gate line;

at a data writing phase of the duty cycle, providing a data writing control signal to the data writing control gate line and providing a data signal to the data line; and

at a light emission phase, controlling a light-emitting sub-circuit of the pixel circuit to emit light by the driving current generated by the driving sub-circuit.

16. The driving method according to claim 15,

wherein:

the pixel circuit includes a light emission control sub-circuit,

each one of the sets of gate lines includes a light emission control gate line, and

a control terminal of the light emission control sub-circuit is electrically coupled to the light emission control gate line,

the driving method further comprising;

at the light emission phase, providing a light emission control signal to the light emission control gate line.

17. The driving method according to claim 15, further comprising:

at an initialization phase of the duty cycle before the compensation phase, providing an initialization control signal to an initialization control gate line.

18. The driving method according to claim 15, wherein a time interval is provided between at least two neighboring ones of the compensation phase, the data writing phase, and the light emission phase.