Display panel, pixel driving circuit, and drving method thereof

• US 10,453,391 B2
• Filed: 11/30/2017
• Issued: 10/22/2019
• Est. Priority Date: 04/28/2017
• Status: Active Grant

• Current Assignee: Shenzhen China Star Optoelectronics Semiconductor Display Technology Co., Ltd.
• Original Assignee: Shenzhen China Star Optoelectronics Semiconductor Display Technology Co., Ltd.
• Inventors: Chen, Xiaolong, Wen, Yi-Chien, Jou, Ming-Jong
• Primary Examiner(s): Eisen, Alexander
• Assistant Examiner(s): Teshome, Kebede T
• Application Number:
  US15/744,080
• Publication Number:
  US 20180374419A1
• Time in Patent Office: 691 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 2300/0852 being a dynamic memory with more than 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 3/3233 with pixel circuitry controlling the current through the light-emitting element

Abstract

The present application provides a pixel driving circuit, which comprises a driving transistor, a first switch, a second switch, a third switch, a fourth switch, a first capacitor, a second capacitor, an initial-voltage-signal terminal, a data-voltage-signal terminal, a reset-voltage-signal terminal, and a driving-voltage-signal terminal. The driving transistor comprises a gate terminal, a source terminal, and a drain terminal. The first capacitor is connected between the source terminal and the gate terminal, the second capacitor is connected between the source terminal and a charge-voltage terminal. The charge-voltage terminal is respectively connected with the reset-voltage-signal terminal and the data-voltage-signal terminal via the first switch and the second switch. The drain terminal is connected with the driving-voltage-signal terminal via the third switch. The gate terminal is connected with the initial-voltage-signal terminal via the fourth switch. The present application further provides a pixel driving method and a display panel.

Claims

1. A pixel driving circuit, comprising a driving transistor, a first switch, a second switch, a third switch, a fourth switch, a first capacitor, a second capacitor, a charge-voltage terminal, an initial-voltage-signal terminal, a data-voltage-signal terminal, a reset-voltage-signal terminal, and a driving-voltage-signal terminal;

wherein the driving transistor comprises a gate terminal, a source terminal, and a drain terminal;

the first capacitor is connected between the source terminal and the gate terminal, the second capacitor is connected between the source terminal and the charge-voltage terminal;

the charge-voltage terminal is respectively connected with the reset-voltage-signal terminal and the data-voltage-signal terminal via the first switch and the second switch;

the drain terminal is connected with the driving-voltage-signal terminal via the third switch;

the gate terminal is connected with the initial-voltage-signal terminal via the fourth switch;

further comprising a first control-signal terminal, wherein the first control-signal terminal is connected with a control terminal of the first switch and a control terminal of the second switch, so as to control on/off of the first switch and the second switch.

2. The pixel driving circuit according to claim 1, further comprising a second control-signal terminal, wherein the second control-signal terminal is connected with a control terminal of the third switch, so as to control on/off of the third switch.

3. The pixel driving circuit according to claim 2, further comprising a third control-signal terminal, wherein the third control-signal terminal is connected with a control terminal of the fourth switch, so as to control on/off of the fourth switch.

4. The pixel driving circuit according to claim 3, further comprising a fifth switch, a fourth control-signal terminal, a light-emitting diode and a negative voltage-signal terminal;

wherein the fourth control-signal terminal is connected with a control terminal of the fifth switch to control on/off of the fifth switch;

the light-emitting diode comprises a positive terminal and a negative terminal, the fifth switch is connected between the source terminal and the positive terminal to control on/off of the driving transistor and the light-emitting diode, the negative terminal is connected with the negative voltage-signal terminal.

5. A display panel, comprising a pixel driving circuit, wherein the pixel driving circuit comprises a driving transistor, a first switch, a second switch, a third switch, a fourth switch, a first capacitor, a second capacitor, a charge-voltage terminal, an initial-voltage-signal terminal, a data-voltage-signal terminal, a reset-voltage-signal terminal, and a driving-voltage-signal terminal;

the driving transistor comprises a gate terminal, a source terminal, and a drain terminal;

the first capacitor is connected between the source terminal and the gate terminal, the second capacitor is connected between the source terminal and the charge-voltage terminal;

the charge-voltage terminal is respectively connected with the reset-voltage-signal terminal and the data-voltage-signal terminal via the first switch and the second switch;

the drain terminal is connected with the driving-voltage-signal terminal via the third switch;

the gate terminal is connected with the initial-voltage-signal terminal via the fourth switch;

further comprising a first control-signal terminal, wherein the first control-signal terminal is connected with a control terminal of the first switch and a control terminal of the second switch, so as to control on/off of the first switch and the second switch.

6. The display panel according to claim 5, further comprising a second control-signal terminal, wherein the second control-signal terminal is connected with a control terminal of the third switch, so as to control on/off of the third switch.

7. The display panel according to claim 6, further comprising a third control-signal terminal, wherein the third control-signal terminal is connected with a control terminal of the fourth switch, so as to control on/off of the fourth switch.

8. The display panel according to claim 7, further comprising a fifth switch, a fourth control-signal terminal, a light-emitting diode and a negative voltage-signal terminal;

wherein the fourth control-signal terminal is connected with a control terminal of the fifth switch to control on/off of the fifth switch;

the light-emitting diode comprises a positive terminal and a negative terminal, the fifth switch is connected between the source terminal and the positive terminal to control on/off of the driving transistor and the light-emitting diode, the negative terminal is connected with the negative voltage-signal terminal.

9. A pixel driving method, comprising:

providing a pixel driving circuit, which comprises a driving transistor, a light-emitting diode, a first capacitor, a second capacitor, a charge-voltage terminal, a data-voltage-signal terminal, and a reset-voltage-signal terminal;

the driving transistor comprises a gate terminal, a source terminal, and a drain terminal;

the first capacitor is connected between the source terminal and the gate terminal, the second capacitor is connected between the source terminal and the charge-voltage terminal;

the charge-voltage terminal is connected with the reset-voltage-signal terminal and the data-voltage-signal terminal;

the source terminal is connected with the light-emitting diode;

a reset-storage phase, loading a data voltage at the charge-voltage terminal, loading an initial voltage at the gate terminal, and loading a driving voltage at the drain terminal to charge the source terminal until a potential difference between the source terminal and the gate terminal is Vth, the Vth is a threshold voltage of the driving transistor, and the Vth is stored in the first capacitor;

a charge-sharing phase, loading a reset voltage at the charge-voltage terminal to change a potential of the gate terminal and a potential of the source terminal, so as to stabilize a driving current of the driving transistor;

a lighting phase, loading the reset voltage at the charge-voltage terminal and loading the driving voltage at the drain terminal to turn on the driving transistor and the light-emitting diode.

10. The pixel driving method according to claim 9, wherein the pixel driving circuit further comprises a first switch, a second switch, a third switch, a fourth switch, a fifth switch, an initial-voltage-signal terminal, a driving-voltage-signal terminal, a first control-signal terminal, a second control-signal terminal, a third control-signal terminal, and a fourth control signal terminal;

the charge-voltage terminal is respectively connected with the reset-voltage-signal terminal and the data-voltage-signal terminal via the first switch and the second switch;

the drain terminal is connected with the driving-voltage-signal terminal via the third switch, the gate terminal is connected with the initial-voltage-signal terminal via the fourth switch;

the fifth switch is connected between the source terminal and the light-emitting diode;

the first control-signal terminal is connected with a control terminal of the first switch and a control terminal of the second switch, the second control-signal terminal is connected with the control terminal of the third switch, and the third control-signal terminal is connected with a control terminal of the fourth switch, and the fourth control-signal terminal is connected with the control terminal of the fifth switch;

in the reset-storage phase, the first control-signal terminal and the fourth control-signal terminal are loaded with a low-level signal, and the second control-signal terminal and the third control-signal terminal are loaded with a high-level signal, so that the second switch, the third switch, and the fourth switch are turned on, and the first switch and the fifth switch are turned off, the charge-voltage terminal is loaded with the data voltage via the second switch, the data voltage is Vdata, the gate terminal is loaded with the initial voltage via the fourth switch, the initial voltage is Vini, and the driving voltage charges the source terminal via the third switch and the driving transistor until a potential of the source terminal is Vini-Vth.

11. The pixel driving method according to claim 10, wherein in the charge-sharing phase, the first control-signal terminal are loaded a high-level signal, the second control-signal terminal, the third control-signal terminal, and the fourth control-signal terminal are loaded with a low-level signal, so that the first switch is turned on, the second switch, the third switch, the fourth switch, and the fifth switch are turned off, and the charge-voltage terminal is loaded with the reset voltage via the first switch, the reset voltage is Vref, and the potential of the gate terminal is Vini+(Vref−

Vdata);

the potential of the source terminal is Vini−

Vth+δ

V, and the potential difference between the gate terminal and the source terminal is Vref−

Vdata+Vth−

δ

V, δ

V=(Vref−

Vdata)*C2/(C1+C2), C1 is a capacitance value of the first capacitor, C2 is the capacitance of the first capacitor, so that a driving current is independent of the threshold voltage.

12. The pixel driving method according to claim 11, wherein the pixel driving circuit further comprises a negative voltage-signal terminal, the light-emitting diode comprises a positive terminal and a negative terminal, the fifth switch is connected between the source terminal and the positive terminal, and the negative terminal is connected with the negative voltage-signal terminal;

in the lighting phase, the first control signal terminal, the second control signal terminal, and the fourth control signal terminal are loaded with a high-level signal, the third control-signal terminal is loaded with a low-level signal, so that the first switch, the third switch and the fifth switch are turned on, and the second switch and the fourth switch are turned off, the charge-voltage terminal is loaded with the reset voltage via the first switch, so that the potential of the source terminal is unchanged, and the third switch, the driving transistor, and the fifth switch are turned on, so that the driving-voltage-signal terminal are conducted with the negative voltage-signal terminal, for driving the light-emitting diode light by the driving current.