Pixel circuit and a driving method thereof, a display device

• US 9,978,312 B2
• Filed: 07/15/2015
• Issued: 05/22/2018
• Est. Priority Date: 04/28/2015
• Status: Active Grant

• Current Assignee: Beijing BOE Optoelectronics Technology Co Ltd. (BOE Technology Group Co., Ltd.), BOE Technology Group Co., Ltd.
• Original Assignee: Beijing BOE Optoelectronics Technology Co Ltd. (BOE Technology Group Co., Ltd.), BOE Technology Group Co., Ltd.
• Inventors: Yang, Shengji, Dong, Xue, Wang, Haisheng, Liu, Yingming, Zhao, Weijie, Ding, Xiaoliang
• Primary Examiner(s): XAVIER, ANTONIO J
• Application Number:
  US15/122,631
• Publication Number:
  US 20170103706A1
• Time in Patent Office: 1,042 Days
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06V 40/1306 non-optical, e.g. ultrasonic or capacitive sensing
• 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 2310/0202 Addressing of scan or signal lines
• CPC Class Codes: G09G 2310/0297 Special arrangements with multiplexing or demultiplexing of display data in the drivers for data electrodes, in a pre-processing circuitry delivering display data to said drivers or in the matrix panel, e.g. multiplexing plural data signals to one D/A converter or demultiplexing the D/A converter output to multiple columns
• 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
• CPC Class Codes: G09G 3/3258 with pixel circuitry controlling the voltage across the light-emitting element

Abstract

The present invention provides a pixel circuit and a driving method thereof, a display device. The pixel circuit comprises a display driving module, a compensation module, a light emitting module and a fingerprint identification module. The compensation module is connected with the display driving module, a first signal terminal, a second signal terminal, a third signal terminal, a first voltage terminal, a data signal terminal and a common voltage terminal respectively. The display driving module is further connected with the light emitting module. The light emitting module is further connected with an enable signal terminal, the first voltage terminal and a second voltage terminal. The fingerprint identification module is connected with a fourth signal terminal, a fifth signal terminal and a readout signal line respectively.

Claims

1. A method for driving a pixel circuit, the pixel circuit comprising a display driving sub-circuit, a compensation sub-circuit, a light emitting sub-circuit and a fingerprint identification sub-circuit;

the compensation sub-circuit, connected with the display driving sub-circuit, a first signal terminal, a second signal terminal, a third signal terminal, a first voltage terminal, a data signal terminal and a common voltage terminal respectively, for compensating the display driving sub-circuit for a threshold voltage through signals inputted by the first voltage terminal and the data signal terminal under the control of the first signal terminal, the second signal terminal, and the third signal terminal;

the display driving sub-circuit, further connected with the light emitting sub-circuit, for driving the light emitting sub-circuit to emit light after the display driving sub-circuit obtains the compensation for the threshold voltage;

the light emitting sub-circuit, further connected with an enable signal terminal, the first voltage terminal and the second voltage terminal, for emitting light through driving of the display driving sub-circuit under the control of the enable signal terminal, the first voltage terminal and the second voltage terminal;

the fingerprint identification sub-circuit, connected with a fourth signal terminal, a fifth signal terminal and a readout signal line respectively, for collecting fingerprint information under the control of the fourth signal terminal and the fifth signal terminal, and transmitting the collected fingerprint information to the readout signal line;

wherein the third signal terminal and the fifth signal terminal are connected with a third scanning signal line, the second signal terminal and the fourth signal terminal are connected with a second scanning signal line, and the first signal terminal is connected with a first scanning signal line;

or,

the second signal terminal and the fifth signal terminal are connected with the second scanning signal line, the first signal terminal and the fourth signal terminal are connected with the first scanning signal line, and the third signal terminal is connected with the third scanning signal line,

the method comprising;

when a first signal terminal inputs a signal, resetting the display driving sub-circuit to remove a residual voltage;

when a second signal terminal inputs a signal, charging the compensation sub-circuit through a signal inputted by a common voltage terminal;

when a fourth signal terminal inputs a signal, resetting the fingerprint identification sub-circuit and collecting fingerprint information;

when a third signal terminal inputs a signal, keeping the compensation sub-circuit in a turn-on state, and compensating the display driving sub-circuit for a threshold voltage based on signals inputted by the first voltage terminal and the data signal terminal;

when a fifth signal terminal inputs a signal, transmitting the collected fingerprint information to a readout signal line by the fingerprint identification sub-circuit;

when an enable signal terminal inputs a signal, turning on the light emitting sub-circuit, and driving the light emitting sub-circuit to emit light by the display driving sub-circuit.

2. The method for driving a pixel circuit according to claim 1, wherein when the third signal terminal and the fifth signal terminal are connected with the third scanning signal line, the second signal terminal and the fourth signal terminal are connected with the second scanning signal line, the method comprising:

at a first phase, the first scanning signal line inputs a signal to the first signal terminal to turn on the fifth transistor, a voltage of the first voltage terminal resets the gate of the driving transistor through the fifth transistor;

at a second phase, the second scanning signal line inputs a signal to the second signal terminal to turn on the fourth transistor, the sixth transistor and the seventh transistor, an input signal of the common voltage terminal charges the first capacitor;

the first transistor, the second transistor, the third transistor, and the fifth transistor are cut off;

the second scanning signal line inputs a signal to the fourth signal terminal to turn on the eighth transistor, the second capacitor is discharged through the eighth transistor;

in the touch control process, a coupling capacitance is formed between a valley line of a fingerprint and the detection electrode, to enable the ninth transistor to be in a cut-off state;

or, in the touch control process, a coupling capacitance is formed between a ridge line of a fingerprint and the detection electrode, to enable the ninth transistor to be in a turn-on state;

at a third phase, the third scanning signal line inputs a signal to the third signal terminal to turn on the third transistor, a signal inputted by the data voltage terminal is outputted to one terminal of the first capacitor, a voltage of the other terminal of the first capacitor jumps due to a bootstrap function of the first capacitor, so as to enable a gate voltage of the driving transistor to jump;

the third scanning signal line inputs a signal to the fifth signal terminal to turn on the tenth transistor, when the ninth transistor is in the cut-off state, an initial current signal of the second terminal of the ninth transistor is transmitted to the readout signal line through the tenth transistor;

when the ninth transistor is in the turn-on state, the ninth transistor amplifies a signal inputted by the common voltage terminal, and transmits it to the readout signal line through the tenth transistor;

at a fourth phase, the enable signal terminal inputs a signal to turn on the first transistor and the second transistor, a current that flows through the first transistor, the driving transistor and the second transistor drives the light emitting device to emit light.

3. The method for driving a pixel circuit according to claim 1, wherein when the second signal terminal and the fifth signal terminal are connected with the second scanning signal line, the first signal terminal and the fourth signal terminal are connected with the first scanning signal line, the method comprising:

at a first phase, the first scanning signal line inputs a signal to the first signal terminal to turn on the fifth transistor, a voltage of the first voltage terminal resets the gate of the driving transistor through the fifth transistor;

the first scanning signal line inputs a signal to the fourth signal terminal to turn on the eighth transistor, the second capacitor is reset through the eighth transistor;

at a second phase, the second scanning signal line inputs a signal to the second signal terminal to turn on the fourth transistor, the sixth transistor and the seventh transistor, an input signal of the first voltage terminal charges the first capacitor;

the first transistor, the second transistor, the third transistor and the fifth transistor are cut off;

in the touch control process, a coupling capacitance is formed between a valley line of a fingerprint and the detection electrode, to enable the ninth transistor to be in a cut-off state;

or, in the touch control process, a coupling capacitance is formed between a ridge line of a fingerprint and the detection electrode, to enable the ninth transistor to be in a turn-on state;

the second scanning signal line inputs a signal to the fifth signal terminal to turn on the tenth transistor, when the ninth transistor is in the cut-off state, an initial current signal of the second terminal of the ninth transistor is transmitted to the readout signal line through the tenth transistor;

when the ninth transistor is in the turn-on state, the ninth transistor amplifies a signal inputted by the common voltage terminal, and transmits it to the readout signal line through the tenth transistor;

at a third phase, the third scanning signal line inputs a signal to the third signal terminal to turn on the third transistor, a signal inputted by the data voltage terminal is outputted to one terminal of the first capacitor, a voltage of the other terminal of the first capacitor jumps due to a bootstrap function of the first capacitor, so as to enable a gate voltage of the driving transistor to jump;

at a fourth phase, the enable signal terminal inputs a signal to turn on the first transistor and the second transistor, a current that flows through the first transistor, the driving transistor and the second transistor drives the light emitting device to emit light.

4. The method for driving a pixel circuit according to claim 1, wherein when the third signal terminal and the fifth signal terminal are connected with the third scanning signal line, the first signal terminal and the fourth signal terminal are connected with the first scanning signal line, the compensation sub-circuit is further connected with the second voltage terminal, the method comprising:

at a first phase, the first scanning signal line inputs a signal to the first signal terminal to turn on the fifth transistor, a voltage of the first voltage terminal resets the gate of the driving transistor through the fifth transistor;

the first scanning signal line inputs a signal to the fourth signal terminal to turn on the eighth transistor, the second capacitor is reset through the eighth transistor;

at a second phase, the second scanning signal line inputs a signal to the second signal terminal to turn on the fourth transistor, the sixth transistor and the seventh transistor, an input signal of the second voltage terminal charges the first capacitor;

the first transistor, the second transistor, the third transistor and the fifth transistor are cut off;

in the touch control process, a coupling capacitance is formed between a valley line of a fingerprint and the detection electrode, to enable the ninth transistor to be in a cut-off state;

or, in the touch control process, a coupling capacitance is formed between a ridge line of a fingerprint and the detection electrode, to enable the ninth transistor to be in a turn-on state;

at a third phase, the third scanning signal line inputs a signal to the third signal terminal to turn on the third transistor, a signal inputted by the data voltage terminal is outputted to one terminal of the first capacitor, a voltage of the other terminal of the first capacitor jumps due to a bootstrap function of the first capacitor, so as to enable a gate voltage of the driving transistor to jump;

the third scanning signal line inputs a signal to the fifth signal terminal to turn on the tenth transistor, when the ninth transistor is in the cut-off state, an initial current signal of the second terminal of the ninth transistor is transmitted to the readout signal line through the tenth transistor;

when the ninth transistor is in the turn-on state, the ninth transistor amplifies a signal inputted by the common voltage terminal, transmits it to the readout signal line through the tenth transistor;

at a fourth phase, the enable signal terminal inputs a signal to turn on the first transistor and the second transistor, a current that flows through the first transistor, the driving transistor and the second transistor drives the light emitting device to emit light.

5. The method for driving a pixel circuit according to claim 1, wherein the display driving sub-circuit comprises:

a driving transistor;

a gate of the driving transistor is connected with the compensation sub-circuit, a first terminal and a second terminal of the driving transistor are connected with the light emitting sub-circuit.

6. The method for driving a pixel circuit according to claim 1, wherein the light emitting sub-circuit comprises:

a first transistor, a second transistor and a light emitting device;

a gate of the first transistor is connected with the enable signal terminal, a first terminal of the first transistor is connected with the display driving sub-circuit, a second terminal of the first transistor is connected with the second voltage terminal;

a gate of the second transistor is connected with the enable signal terminal, a first terminal of the second transistor is connected with an anode of the light emitting device, a second terminal of the second transistor is connected with the display driving sub-circuit;

a cathode of the light emitting device is connected with the first voltage terminal.

7. The method for driving a pixel circuit according to claim 1, wherein the fingerprint identification sub-circuit comprises:

an eighth transistor, a ninth transistor, a tenth transistor, a second capacitor and a detection electrode;

a gate of the eighth transistor is connected with the fourth signal terminal, a first terminal of the eighth transistor is connected with the common voltage terminal, a second terminal of the eighth transistor is connected with one terminal of the second capacitor;

a gate of the ninth transistor is connected with the one terminal of the second capacitor, a first terminal of the ninth transistor is connected with the common voltage terminal, a second terminal of the ninth transistor is connected with a first terminal of the tenth transistor;

a gate of the tenth transistor is connected with the fifth signal terminal, a second terminal of the tenth transistor is connected with the readout signal line;

the detection electrode is connected with the one terminal of the second capacitor;

the other terminal of the second capacitor is connected with the fifth signal terminal.

8. The method for driving a pixel circuit according to claim 1, wherein the compensation sub-circuit comprises:

a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, a seventh transistor and a first capacitor;

a gate of the third transistor is connected with the third signal terminal, a first terminal of the third transistor is connected with the data signal terminal, a second terminal of the third transistor is connected with one terminal of the first capacitor;

a gate of the fourth transistor is connected with the second signal terminal, a first terminal of the fourth transistor is connected with the common voltage terminal, a second terminal of the fourth transistor is connected with the one terminal of the first capacitor;

a gate of the fifth transistor is connected with the first signal terminal, a first terminal of the fifth transistor is connected with a first terminal of the seventh transistor, a second terminal of the fifth transistor is connected with the first voltage terminal;

a gate of the sixth transistor is connected with the second signal terminal, a first terminal of the sixth transistor is connected with the display driving sub-circuit, a second terminal of the sixth transistor is connected with the common voltage terminal;

a gate of the seventh transistor is connected with the second signal terminal, a first terminal of the seventh transistor is connected with the other terminal of the first capacitor, a second terminal of the seventh transistor is connected with the display driving sub-circuit.

9. The method for driving a pixel circuit according to claim 1, wherein the compensation sub-circuit comprises:

a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, a seventh transistor and a first capacitor;

a gate of the third transistor is connected with the third signal terminal, a first terminal of the third transistor is connected with the data signal terminal, a second terminal of the third transistor is connected with one terminal of the first capacitor;

a gate of the fourth transistor is connected with the second signal terminal, a first terminal of the fourth transistor is connected with the first voltage terminal, a second terminal of the fourth transistor is connected with the one terminal of the first capacitor;

a gate of the fifth transistor is connected with the first signal terminal, a first terminal of the fifth transistor is connected with the other terminal of the first capacitor, a second terminal of the fifth transistor is connected with the first voltage terminal;

a gate of the sixth transistor is connected with the second signal terminal, a first terminal of the sixth transistor is connected with the display driving sub-circuit, a second terminal of the sixth transistor is connected with the common voltage terminal;

a gate of the seventh transistor is connected with the second signal terminal, a first terminal of the seventh transistor is connected with the other terminal of the first capacitor, a second terminal of the seventh transistor is connected with the display driving sub-circuit.

10. The method for driving a pixel circuit according to claim 1, wherein the compensation sub-circuit comprises:

a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, a seventh transistor and a first capacitor;

a gate of the third transistor is connected with the third signal terminal, a first terminal of the third transistor is connected with the data signal terminal, a second terminal of the third transistor is connected with one terminal of the first capacitor;

a gate of the fourth transistor is connected with the second signal terminal, a first terminal of the fourth transistor is connected with the second voltage terminal, a second terminal of the fourth transistor is connected with the one terminal of the first capacitor;

a gate of the fifth transistor is connected with the first signal terminal, a first terminal of the fifth transistor is connected with the other terminal of the first capacitor, a second terminal of the fifth transistor is connected with the first voltage terminal;

a gate of the sixth transistor is connected with the second signal terminal, a first terminal of the sixth transistor is connected with the display driving sub-circuit, a second terminal of the sixth transistor is connected with the common voltage terminal;

a gate of the seventh transistor is connected with the second signal terminal, a first terminal of the seventh transistor is connected with the other terminal of the first capacitor, a second terminal of the seventh transistor is connected with the display driving sub-circuit.