OLED pixel circuit and method for driving the same, display apparatus

• US 10,726,790 B2
• Filed: 09/21/2018
• Issued: 07/28/2020
• Est. Priority Date: 11/29/2017
• Status: Active Grant

• Current Assignee: BOE Technology Group Co., Ltd.
• Original Assignee: BOE Technology Group Co., Ltd.
• Inventors: Shi, Ling
• Primary Examiner(s): Dharia, Prabodh M
• Application Number:
  US16/138,660
• Publication Number:
  US 20190164500A1
• Time in Patent Office: 676 Days
• Field of Search: 345 55, 345 76, 345205, 370254
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• 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 2300/0439 Pixel structures
• 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 2310/0262 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 2310/08 Details of timing specific for flat panels, other than clock recovery
• 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
• 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
• CPC Class Codes: H10K 59/12 Active-matrix OLED [AMOLED] displays

Abstract

An OLED pixel circuit includes an initialization and compensation sub-circuit configured to initialize a driving sub-circuit and compensate a threshold voltage of the driving sub-circuit; a data writing sub-circuit configured to input a signal of a second signal end to the driving sub-circuit; a light-emitting control sub-circuit configured to input a signal of the first voltage end to the driving sub-circuit, and input a driving signal output by the driving sub-circuit to a light emitting sub-circuit; the driving sub-circuit configured to output the driving signal; and the light emitting sub-circuit configured to emit light.

Claims

1. An OLED pixel circuit, comprising:

an initialization and compensation sub-circuit, connected to a driving sub-circuit, a first signal input, an initial voltage input and light emitting sub-circuit, wherein the initialization and compensation sub-circuit is configured to initialize the driving sub-circuit and the light emitting sub-circuit and compensate a threshold voltage of the driving sub-circuit according to a signal input by the initial voltage input under control of a signal from the first signal input;

a data writing sub-circuit, connected to the driving sub-circuit, the first signal input and a second signal input, wherein the data writing sub-circuit is configured to input a signal of the second signal input to the driving sub-circuit under control of a signal from the first signal input; and

a light-emitting control sub-circuit, connected to the driving sub-circuit, a light emitting sub-circuit, an enable signal input and a first voltage input, wherein the light-emitting control sub-circuit is configured to input a signal of the first voltage input to the driving sub-circuit, and to input a driving signal output by the driving sub-circuit to the light emitting sub-circuit under control of a signal from the enable signal input, wherein

the driving sub-circuit is further connected to a third signal input, and is configured to output the driving signal under control of a signal from the third signal input and in a case of the signal of the first voltage input being input to the driving sub-circuit; and

the light emitting sub-circuit is further connected to a second voltage input, and is configured to emit light under a driving of the second voltage input and the driving signal input by the light-emitting control sub-circuit;

the initialization and compensation sub-circuit includes a second transistor, a third transistor and a fourth transistor;

a gate electrode of the second transistor is connected to the first signal input, a first electrode of the second transistor is connected to the initial voltage input, and a second electrode of the second transistor is connected to the driving sub-circuit;

a gate electrode of the third transistor is connected to the first signal input, a first electrode of the third transistor is connected to the first electrode of the second transistor, and a second electrode of the third transistor is connected to the driving sub-circuit; and

a gate electrode of the fourth transistor is connected to the first signal input, a first electrode of the fourth transistor is connected to the initial voltage input, and a second electrode of the fourth transistor is directly connected to the light emitting sub-circuit.

2. The OLED pixel circuit according to claim 1, wherein, the enable signal input and the third signal input are connected with a same signal input.

3. The OLED pixel circuit according to claim 1, wherein, the driving sub-circuit comprises a first transistor, a driving transistor and a reservoir capacitor, wherein

a first end of the reservoir capacitor is connected to the data writing sub-circuit, and a second end of the reservoir capacitor is connected to a first electrode of the driving transistor;

a gate electrode of the first transistor is connected to the third signal input, a first electrode of the first transistor is connected to the first end of the reservoir capacitor, and a second electrode of the first transistor is connected to a gate electrode of the driving transistor; and

the gate electrode of the driving transistor is further connected to the initialization and compensation sub-circuit, the first electrode of the driving transistor is further connected to the light-emitting control sub-circuit, and a second electrode of the driving transistor is connected to the initialization and compensation sub-circuit and the light-emitting control sub-circuit.

4. The OLED pixel circuit according to claim 1, wherein, the data writing sub-circuit comprises a fifth transistor, wherein

a gate electrode of the fifth transistor is connected to the first signal input, a first electrode of the fifth transistor is connected to the second signal input, and a second electrode of the fifth transistor is connected to the driving sub-circuit.

5. The OLED pixel circuit according to claim 1, wherein, the light-emitting control sub-circuit comprises a sixth transistor and a seventh transistor, wherein

a gate electrode of the sixth transistor is connected to the enable signal input, a first electrode of the sixth transistor is connected to the first voltage input, and a second electrode of the sixth transistor is connected to the driving sub-circuit;

and

a gate electrode of the seventh transistor is connected to the enable signal input, a first electrode of the seventh transistor is connected to the driving sub-circuit, and a second electrode of the seventh transistor is connected to the light emitting sub-circuit.

6. The OLED pixel circuit according to claim 1, wherein, the driving sub-circuit comprises a first transistor, a driving transistor and a reservoir capacitor;

the initialization and compensation sub-circuit comprises a second transistor, a third transistor and a fourth transistor;

the data writing sub-circuit comprises a fifth transistor;

the light-emitting control sub-circuit comprises a sixth transistor and a seventh transistor; and

the light emitting sub-circuit comprises a light-emitting device, wherein

a gate electrode of the fifth transistor is connected to the first signal input, a first electrode of the fifth transistor is connected to the second signal input, and a second electrode of the fifth transistor is connected to a first end of the reservoir capacitor;

a second end of the reservoir capacitor is connected to a first electrode of the driving transistor;

a gate electrode of the first transistor is connected to the third signal input, a first electrode of the first transistor is connected to the first end of the reservoir capacitor, and a second electrode of the first transistor is connected to a gate electrode of the driving transistor and a second electrode of the second transistor;

the gate electrode of the driving transistor is further connected the second electrode of the second transistor, the first electrode of the driving transistor is further connected to a second electrode of the sixth transistor, and a second electrode of the driving transistor is connected to a second electrode of the third transistor and a first electrode of the seventh transistor;

a gate electrode of the sixth transistor is connected to the enable signal input, and a first electrode of the sixth transistor is connected to the first voltage input;

a gate electrode of the seventh transistor is connected to the enable signal input, and a second electrode of the seventh transistor is connected to an anode of the light-emitting device;

a gate electrode of the second transistor is connected to the first signal input, and a first electrode of the second transistor is connected to the initial voltage input;

a gate electrode of the third transistor is connected to the first signal input, and a first electrode of the third transistor is connected to the initial voltage input;

a gate electrode of the fourth transistor is connected to the first signal input, a first electrode of the fourth transistor is connected to the initial voltage input, and a second electrode of the fourth transistor is connected to the anode of the light-emitting device; and

a cathode of the light-emitting device is connected to the second voltage input.

7. A display apparatus, comprising the OLED pixel circuit of claim 1, wherein, the OLED pixel circuit comprises:

an initialization and compensation sub-circuit, connected to a driving sub-circuit, a first signal input and an initial voltage input, and configured to initialize the driving sub-circuit and compensate a threshold voltage of the driving sub-circuit according to a signal input by the initial voltage input under control of a signal from the first signal input;

a data writing sub-circuit, connected to the driving sub-circuit, the first signal input and a second signal input, and configured to input a signal of the second signal input to the driving sub-circuit under control of a signal from the first signal input;

a light-emitting control sub-circuit, connected to the driving sub-circuit, a light emitting sub-circuit, an enable signal input and a first voltage input, and configured to input a signal of the first voltage input to the driving sub-circuit, and to input a driving signal output by the driving sub-circuit to the light emitting sub-circuit under control of a signal from the enable signal input;

the driving sub-circuit, further connected to a third signal input, and configured to output the driving signal under control of a signal from the third signal input and in a case of the signal of the first voltage input being input to the driving sub-circuit; and

a light emitting sub-circuit, further connected to a second voltage input, and configured to emit light under a driving of the second voltage input and the driving signal input by the light-emitting control sub-circuit.

8. A method for driving an OLED pixel circuit according to claim 1, wherein, the driving sub-circuit comprises a first transistor, a driving transistor and a reservoir capacitor;

the initialization and compensation sub-circuit comprises a second transistor, a third transistor and a fourth transistor; and

the data writing sub-circuit comprises a fifth transistor;

wherein, the method, comprising;

in a first phase of a frame, inputting, via the first signal input, a turn-on signal to control the second transistor, the third transistor and the fifth transistor to be turned on, and inputting a reset signal output from the initial voltage input to the driving transistor via the second transistor, so that initializing the driving transistor and compensating a threshold voltage of the driving sub-circuit; and

inputting the reset signal output from the initial voltage input further to the light emitting sub-circuit via the fourth transistor to initialize the light emitting sub-circuit;

inputting, by the fifth transistor, a data signal output via the second signal input to the reservoir capacitor via the fifth transistor under control of the signal from the first signal input, to store the data signal into the reservoir capacitor;

in a second phase of the frame, inputting, by a light-emitting control sub-circuit, a supply voltage output via a first voltage input to the driving sub-circuit under control of a signal from an enable signal input;

outputting, by the driving sub-circuit, a driving signal under control of a signal from a third signal input;

inputting, by the light-emitting control sub-circuit, the driving signal output by the driving sub-circuit to a light emitting sub-circuit under control of a signal from the enable signal input; and

emitting light, by the light emitting sub-circuit under a driving of the driving signal input by the light-emitting control sub-circuit and a second voltage input.

9. The method according to claim 8, wherein, the light-emitting control sub-circuit comprises a sixth transistor and a seventh transistor, the method further comprises:

in the second phase of the frame, inputting, via the third signal input, a turn-on signal to control the first transistor to be turned on; and

transmitting, by the reservoir capacitor, the data signal stored therein to a gate electrode of the driving transistor via the first transistor, to control the driving transistor to be turned on;

inputting, via the enable signal input, a turn-on signal to control the sixth transistor and the seventh transistor to be turned on;

inputting a supply voltage output via the first voltage input to the driving transistor via the sixth transistor;

outputting, by the driving transistor, the driving signal under control of the data signal and the supply voltage, and transmitting the driving signal to the light emitting sub-circuit via the seventh transistor; and

the light emitting sub-circuit emitting light under control of the driving signal and the supply voltage output by the second voltage input.

10. The method according to claim 9, wherein, in the second phase of the frame, the turn-on signals of the third signal input and the enable signal input are input simultaneous;

or,

in a first sub-phase of the second phase of the frame, inputting a turn-on signal via the third signal input; and

the reservoir capacitor transmits the data signal stored therein to the gate electrode of the driving transistor via the first transistor; and

in a second sub-phase of the second phase of the frame, inputting a turn-on signal via the third signal input continuously, and inputting a turn-on signal via the enable signal input.