A PIXEL CIRCUIT, A DRIVING METHOD THEREOF, AND A DISPLAY APPARATUS

• US 20200135114A1
• Filed: 09/06/2018
• Published: 04/30/2020
• Est. Priority Date: 09/15/2017
• Status: Abandoned Application

• Current Assignee: BOE Technology Group Co., Ltd., Chengdu BOE Optoelectronics Technology Company Limited (BOE Technology Group Co., Ltd.)
• Original Assignee: Chengdu BOE Optoelectronics Technology Company Limited (BOE Technology Group Co., Ltd.)
• Inventors: Lee, Sangwon, Ko, Minho, Kang, Sanghun, Tan, Wen, Ko, Youngyik, Dong, Wanli
• Application Number:
  US16/616,964
• Publication Number:
  US 20200135114A1
• Time in Patent Office: Days
• CPC Class Codes: G09G 2300/0819 used for counteracting undesired variations, e.g. feedback or autozeroing
• 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 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• 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 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
• 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 present application discloses a pixel circuit for a display panel. The circuit includes a first transistor coupled to a data line and configured to transfer a data signal in response to an N-th scan signal corresponding to an N-th row of pixels in the display panel. Additionally, the circuit includes a second transistor coupled to the first transistor and configured to generate a driving signal based on the data signal. The circuit further includes a third transistor coupled to the second transistor and configured to compensate a threshold voltage of the second transistor in response to an (N−1)-th scan signal corresponding to a previous (N−1)-th row of pixels in the display panel. Furthermore, the circuit includes a capacitor coupled between the second transistor and a first power voltage port for storing the data signal. Moreover, the circuit includes a light emitter driven by the driving signal to emit light.

Claims

1. A circuit for driving a light-emitting pixel in a display panel comprising:

a first transistor coupled to a data line and configured to transfer a data signal in response to an N-th scan signal corresponding to a current N-th row of multiple rows of pixels in the display panel, wherein N is an integer greater than 2;

a second transistor coupled to the first transistor and configured to generate a driving signal based on the data signal;

a third transistor coupled to the second transistor and configured to compensate a threshold voltage of the second transistor in response to an (N−

1)-th scan signal corresponding to a previous (N−

1)-th row of the multiple rows of pixels in the display panel;

a capacitor coupled between the second transistor and a first power voltage port for storing the data signal transferred from the first transistor; and

a light emitter coupled to the second transistor to emit light controlled by the driving signal.

2. The circuit of claim 1, further comprising a fourth transistor coupled to a first electrode of the light emitter and an initializing voltage port and configured to discharge the data signal stored in the capacitor using an initializing voltage received at the initializing voltage port in response to the (N−

1)-th scan signal.

3. The circuit of claim 2, wherein the fourth transistor comprises a first electrode coupled to the initializing voltage port, a second electrode coupled to the first electrode of the light emitter, and a control electrode coupled to an (N−

1)-th scan line receiving the (N−

1)-th scan signal.

4. The circuit of claim 3, further comprising:

a fifth transistor coupled to the second transistor and configured to provide a first power voltage received at the first power voltage port to the second transistor in response to an N-th emission-control signal corresponding to the N-th row of the multiple rows of pixels in the display panel;

a sixth transistor coupled to the second transistor and configured to pass the driving signal to the light emitter in response to an (N+1)-th emission-control signal corresponding to a next (N+1)-th row of the multiple rows of pixels in the display panel.

5. The circuit of claim 4, wherein the fifth transistor comprises a first electrode coupled to the first power voltage port, a second electrode coupled to a second electrode of the first transistor and a first electrode of the second transistor, and a control electrode coupled to an N-th emission-control line receiving the N-th emission-control signal.

6. The circuit of claim 4, wherein the sixth transistor comprises a first electrode coupled to a second electrode of the second transistor and a second electrode of the third transistor, a second electrode coupled to the first electrode of the light emitter and the second electrode of the fourth transistor, and a control electrode coupled to an (N+1)-th emission-control line receiving the (N+1)-th emission-control signal.

7. The circuit of claim 1, wherein the first transistor comprises a first electrode coupled to the data line receiving the data signal, a second electrode coupled to a first electrode of the second transistor, and a control electrode coupled to an N-th scan line receiving the N-th scan signal.

8. The circuit of claim 1, wherein the second transistor comprises a first electrode coupled to the second electrode of the first transistor, a second electrode coupled to a second electrode of the third transistor, and a control electrode coupled to a second electrode of the capacitor and a first electrode of the third transistor.

9. The circuit of claim 1, wherein the third transistor comprises a first electrode coupled to a control electrode of the second transistor, a second electrode coupled to a second electrode of the second transistor, and a control electrode coupled to an (N−

1)-th scan line receiving the (N−

1)-th scan signal.

10. The circuit of claim 1, wherein the capacitor comprises a first electrode coupled to the first power voltage port and a second electrode coupled to a control electrode of the second transistor and a first electrode of the third transistor.

18. A display apparatus comprising a circuit of claim 1.

11. A pixel circuit for driving light emission of a pixel in an arbitrary N-th row of multiple rows of pixels in a display panel comprising a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, a capacitor, and a light emitter, wherein N is an integer greater than 2:

a first electrode of the first transistor is coupled to a data line receiving a data signal, a second electrode of the first transistor is coupled to a first electrode of the second transistor, and a control electrode of the first transistor is coupled to an N-th scan line associated with the display panel;

a first electrode of the second transistor is coupled to the second electrode of the first transistor, a second electrode of the second transistor is coupled to a second electrode of the third transistor, and a control electrode of the second transistor is coupled to a first electrode of the third transistor and a second electrode of the capacitor;

a control electrode of the third transistor is coupled to an (N−

1)-th scan line associated with the display panel;

a first electrode of the fourth transistor is coupled to an initializing voltage port, a second electrode of the fourth transistor is coupled to a first electrode of the light emitter, and a control electrode of the fourth transistor is coupled to the (N−

1)-th scan line;

a first electrode of the fifth transistor is coupled to a first power voltage port receiving a first power voltage, a second electrode of the fifth transistor is coupled to the second electrode of the first transistor and the first electrode of the second transistor, and a control electrode of the fifth transistor is coupled to an N-th emission-control line associated with the display panel;

a first electrode of the sixth transistor is coupled to the second electrode of the second transistor and the second electrode of the third transistor, a second electrode of the sixth transistor is coupled to the first electrode of the light emitter and the second electrode of the fourth transistor, and a control electrode of the sixth transistor is coupled to an (N+1)-th emission-control line;

a first electrode of the capacitor is coupled to the first power voltage port and a second electrode of the capacitor is coupled to the control electrode of the second transistor and the first electrode of the third transistor; and

a second electrode of the light emitter is coupled to a second power voltage port receiving a second power voltage, the second power voltage being lower than the first power voltage.

13. A method of driving the pixel circuit of claim 11 in each scan cycle of displaying one frame of image comprising:

providing a transistor-turn-on voltage signal to the (N−

1)-th scan line and the (N+1)-th emission-control line in a first period of a scan cycle;

setting the initializing voltage port at an initializing voltage;

making the second transistor, the third transistor, the fourth transistor, and the sixth transistor at an on-state to make each of a first common node of the control electrode of the second transistor and the first electrode of the third transistor, a second common node of the second electrode of the first transistor and the first electrode of the second transistor, a third common node of the second electrode of the second transistor and the first electrode of the sixth transistor, and a fourth common node of the second electrode of the fourth transistor and the second electrode of the sixth transistor to be at the initializing voltage; and

discharging the data signal stored in the capacitor to the initializing voltage port.

14. The method of claim 13, further comprising:

providing a transistor-turn-on voltage signal to the (N−

1)-th scan line and the N-th scan line in a second period of the scan cycle;

sending a data signal to the data line;

making the first transistor, the second transistor, and the third transistor at an on-state to transfer the data signal from the first electrode of the first transistor to the first electrode of the second transistor;

compensating a threshold voltage of the second transistor using the third transistor; and

generating a driving signal based on the data signal by the second transistor to drive the light emitter to emit light.

15. The method of claim 14, further comprising:

providing a transistor-turn-on voltage signal to the N-th scan line in a third period after the second period of the scan cycle;

keeping the first transistor and the second transistor at an on-state to transfer the data signal from the first electrode of the first transistor to the first electrode of the second transistor;

maintaining the threshold voltage of the second transistor being compensated the same as that in the second period; and

writing the data signal from the data line to the first electrode of the second transistor to maintain the driving signal for driving the light emitter to emit light.

16. The method of claim 15, further comprising:

providing a transistor-turn-on voltage signal to the N-th emission-control line in a fourth period of the scan cycle; and

making the second transistor and the fifth transistor at an on-state to pass the first power voltage to both the first electrode and the second electrode of the second transistor.

17. The method of claim 16, further comprising:

providing a transistor-turn-on voltage signal to the N-th emission-control line and the (N+1)-th emission-control line in a fifth period of the scan cycle;

making the second transistor, the fifth transistor, and the sixth transistor at an on-state; and

driving the light emitter to emit light based on the driving signal that is substantially independent of the threshold voltage of the second transistor.

12. A method of driving light emission of a light-emitting pixel in a display panel comprising:

transferring a data signal from a data line via a first transistor to a current N-th row of multiple rows of pixels in the display panel in response to an N-th scan signal, wherein N is an integer greater than 2;

generating a driving signal via a second transistor coupled to the first transistor based on the data signal;

coupling a third transistor to the second transistor to compensate a threshold voltage of the second transistor in response to an (N−

1)-th scan signal corresponding to a previous (N−

1)-th row of the multiple rows of pixels in the display panel;

storing the data signal transferred from the first transistor in a capacitor coupled between the second transistor and a first power voltage port; and

driving a light emitter coupled to the second transistor to emit light based on the driving signal.