# US 12,223,906 B2 · Pixel circuit, driving method and display device

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- Number: US 12,223,906 B2
- Document ID: US12223906B2
- Status: Granted
- Kind: B2
- Application number: 17/788,725
- Filed: 2021-07-30
- Published: 2024-05-23
- Granted: 2025-02-11
- Earliest claimed: 2021-07-30
- Assignees: Boe Technology Group Co., Ltd.
- Applicants: Boe Technology Group Co., Ltd.
- Inventors: Libin Liu; Shiming Shi; Xiyu Zhao; Yu Feng; Li Wang
- Web page: https://patentgrep.com/patent/US12223906B2

## CPC

- G09G 3/3233: with pixel circuitry controlling the current through the light-emitting element
- G09G 3/3258: with pixel circuitry controlling the voltage across the light-emitting element
- G09G 3/32: semiconductive, e.g. using light-emitting diodes [LED]
- G09G 3/3225: using an active matrix
- H10K 59/1213: {the pixel elements being TFTs}
- G09G 2300/0417: Special arrangements specific to the use of low carrier mobility technology
- G09G 2300/0452: Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
- G09G 2300/0819: used for counteracting undesired variations, e.g. feedback or autozeroing
- G09G 2300/0842: forming a memory circuit, e.g. a dynamic memory with one capacitor
- G09G 2300/0852: being a dynamic memory with more than one capacitor
- 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
- G09G 2310/0251: Precharge or discharge of pixel before applying new pixel voltage
- 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
- G09G 2310/062: Waveforms for resetting a plurality of scan lines at a time
- G09G 2310/08: Details of timing specific for flat panels, other than clock recovery
- G09G 2320/0214: with crosstalk due to leakage current of pixel switch in active matrix panels
- G09G 2320/0219: Reducing feedthrough effects in active matrix panels, i.e. voltage changes on the scan electrode influencing the pixel voltage due to capacitive coupling
- G09G 2320/0233: Improving the luminance or brightness uniformity across the screen
- G09G 2320/0238: Improving the black level
- G09G 2320/0247: Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
- G09G 2320/0257: Reduction of after-image effects
- G09G 2320/043: Preventing or counteracting the effects of ageing
- G09G 2320/045: Compensation of drifts in the characteristics of light emitting or modulating elements
- G09G 2330/021: Power management, e.g. power saving
- G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00)
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES

## Abstract

A pixel circuit, a driving method and a display device. The pixel circuit includes a driving circuit, a first control circuit, a compensation control circuit and a first initialization circuit; the first control circuit is configured to control to connect the control end of the driving circuit and the connection node under the control of a first scan signal; the compensation control circuit is configured to control to connect the connection node and the first end of the driving circuit under the control of a second scan signal; the first initialization circuit is configured to write a first initialization voltage into the connection node under the control of an initialization control signal; the driving circuit is configured to control to connect the first end and a second end of the driving circuit under the control of a potential of the control end thereof.

## Claims

### Claim 1

A pixel circuit, comprising a driving circuit, a first control circuit, a compensation control circuit and a first initialization circuit; wherein
the first control circuit is respectively electrically connected to a first scan line, a control end of the driving circuit and a connection node, and is configured to control to connect the control end of the driving circuit and the connection node under the control of a first scan signal provided by the first scan line;
the compensation control circuit is respectively electrically connected to a second scan line, the connection node and a first end of the driving circuit, and is configured to control to connect the connection node and the first end of the driving circuit under the control of a second scan signal provided by the second scan line;
the first initialization circuit is electrically connected to an initialization control line, a first initialization voltage line and the connection node, respectively, and is configured to write a first initialization voltage provided by the first initialization voltage line into the connection node under the control of an initialization control signal provided by the initialization control line;
the driving circuit is configured to control to connect the first end of the driving circuit and a second end of the driving circuit under the control of a potential of the control end of the driving circuit;
the pixel circuit further comprises a reset circuit; wherein
the reset circuit is electrically connected to a third scan line, a reset voltage line and the second end of the driving circuit respectively, and is configured to write a reset voltage provided by the reset voltage line into the second end of the driving circuit under the control of a third scan signal provided by the third scan line;
wherein the reset voltage line and a first voltage line are a same voltage line, and a voltage value of the reset voltage is greater than a voltage value of the first initialization voltage.

### Claim 2 (depends on 1)

The pixel circuit according to claim 1, wherein the first control circuit comprises a first transistor;
a control electrode of the first transistor is electrically connected to the first scan line, a first electrode of the first transistor is electrically connected to the control end of the driving circuit, and a second electrode of the first transistor is electrically connected to the connection node;
the first transistor is an oxide thin film transistor.

### Claim 3 (depends on 1)

The pixel circuit according to claim 1, wherein the compensation control circuit comprises a second transistor;
a control electrode of the second transistor is electrically connected to the second scan line, a first electrode of the second transistor is electrically connected to the connection node, and a second electrode of the second transistor is electrically connected to the first end of the driving circuit.

### Claim 4 (depends on 3)

The pixel circuit according to claim 3, wherein the second transistor is a low temperature polysilicon thin film transistor.

### Claim 5 (depends on 1)

The pixel circuit according to claim 1, wherein the first initialization circuit comprises a third transistor;
a control electrode of the third transistor is electrically connected to the initialization control line, a first electrode of the third transistor is electrically connected to the first initialization voltage line, and a second electrode of the third transistor is electrically connected to the connection node.

### Claim 6 (depends on 5)

The pixel circuit according to claim 5, wherein the third transistor is a low temperature polysilicon thin film transistor.

### Claim 7 (depends on 1)

The pixel circuit according to claim 1, wherein the reset circuit comprises a fourth transistor;
a control electrode of the fourth transistor is electrically connected to the third scan line, a first electrode of the fourth transistor is electrically connected to the reset voltage line, and a second electrode of the fourth transistor is electrically connected to the second end of the driving circuit.

### Claim 8 (depends on 1)

The pixel circuit according to claim 1, wherein the driving circuit comprises a driving transistor;
the driving transistor is a single-gate transistor, a gate electrode of the driving transistor is electrically connected to the control end of the driving circuit, a first electrode of the driving transistor is electrically connected to the first end of the driving circuit, and a second electrode of the driving transistor is electrically connected to the second end of the driving circuit; or,
the drive transistor is a double-gate transistor, a first gate electrode of the driving transistor is electrically connected to the control end of the driving circuit, a second gate electrode of the drive transistor is electrically connected to the first voltage line, and the first electrode of the driving transistor is electrically connected to the first end of the driving circuit, and the second electrode of the driving transistor is electrically connected to the second end of the driving circuit; the first gate electrode is a top gate, and the second gate electrode is a bottom gate.

### Claim 9 (depends on 1)

The pixel circuit according to claim 1, further comprising a light-emitting element, a light-emitting control circuit and a second initialization circuit;
the light-emitting control circuit is respectively electrically connected to a light-emitting control line, a first voltage line, the second end of the driving circuit, and the first end of the driving circuit and a first electrode of the light-emitting element, is configured to, under the control of a light-emitting control signal provided by the light-emitting control line, control to connect the first voltage line and the second end of the driving circuit, and connect the first end of the driving circuit and the first electrode of the light-emitting element;
the second initialization circuit is respectively electrically connected to a fourth scan line, a second initialization voltage line and the first electrode of the light-emitting element, and is configured to write a second initialization voltage provided by the second initialization voltage line into the first electrode of the light-emitting element under the control of a fourth scan signal provided by the fourth scan line;
a second electrode of the light-emitting element is electrically connected to the second voltage line.

### Claim 10 (depends on 9)

The pixel circuit according to claim 9, wherein the light-emitting control circuit comprises a fifth transistor and a sixth transistor;
a control electrode of the fifth transistor is electrically connected to the light-emitting control line, a first electrode of the fifth transistor is electrically connected to the first voltage line, and a second electrode of the fifth transistor is electrically connected to the second end of the driving circuit;
a control electrode of the sixth transistor is electrically connected to the light-emitting control line, a first electrode of the sixth transistor is electrically connected to the first end of the driving circuit, and a second electrode of the sixth transistor is electrically connected to the first electrode of the light-emitting element;
the second initialization circuit includes a seventh transistor;
a control electrode of the seventh transistor is electrically connected to the fourth scan line, a first electrode of the seventh transistor is electrically connected to the second initialization voltage line, and a second electrode of the seventh transistor is electrically connected to the first electrode of the light-emitting element.

### Claim 11 (depends on 10)

The pixel circuit according to claim 10, wherein the seventh transistor is an oxide thin film transistor.

### Claim 12 (depends on 9)

The pixel circuit according to claim 9, further comprising a data writing-in circuit and an energy storage circuit;
the data writing-in circuit is electrically connected to the second scan line, a data line and the second end of the driving circuit respectively, and is configured to write a data voltage on the data line into the second end of the driving circuit under the control of a second scan signal provided by the second scan line;
the energy storage circuit is electrically connected to the control end of the driving circuit and configured to store electrical energy.

### Claim 13 (depends on 12)

The pixel circuit according to claim 12, wherein the data writing-in circuit comprises an eighth transistor, the energy storage circuit comprises a storage capacitor, and the driving circuit comprises a driving transistor;
a control electrode of the eighth transistor is electrically connected to the second scan line, a first electrode of the eighth transistor is electrically connected to the data line, and a second electrode of the eighth transistor is electrically connected to the second end of the driving circuit;
a first end of the storage capacitor is electrically connected to the control end of the driving circuit, and a second end of the storage capacitor is electrically connected to the first voltage line.

### Claim 14 (depends on 1)

A driving method, applied to the pixel circuit according to claim 1, wherein a display period includes an initialization phase and a data writing-in phase; the driving method comprises:
in the initialization phase, controlling, by the first control circuit, to connect the control end of the driving circuit and the connection node under the control of the first scan signal, and writing, by the first initialization circuit, the first initialization voltage into the connection node under the control of the initialization control signal, so that the first initialization voltage is written into the control end of the driving circuit, the driving circuit controls to connect the first end and the second end of the driving circuit at the beginning of the data writing-in phase;
in the data writing-in phase, controlling, by the first control circuit, to connect the control end of the driving circuit and the connection node under the control of the first scan signal, and controlling, by the compensation control circuit, to connect the connection node and the first end of the driving circuit under the control of the second scan signal, so that the control end of the driving circuit is connected to the first end of the driving circuit.

### Claim 15 (depends on 14)

The driving method according to claim 14, wherein the pixel circuit further comprises a reset circuit; the driving method further comprises:
in the initialization phase, writing, by the reset circuit, a reset voltage to the second end of the driving circuit under the control of the third scan signal.

### Claim 16 (depends on 14)

The driving method according to claim 14, wherein the pixel circuit further comprises a light emitting element and a second initialization circuit; the driving method further comprises:
writing, by the second initialization circuit, a second initialization voltage into a first electrode of the light-emitting element under the control of a fourth scan signal, so as to control the light-emitting element not to emit light.

### Claim 17 (depends on 14)

The driving method according to claim 14, wherein the pixel circuit further comprises a light emitting control circuit, a data writing-in circuit and an energy storage circuit, and the display period further comprises a light-emitting phase after the data writing-in phase; the driving method further includes:
in the data writing stage, writing, by the data writing-in circuit, a data voltage Vdata on the data line into the second end of the driving circuit under the control of the second scan signal;
at the beginning of the data writing-in phase, controlling, by the driving circuit, to connect the first end of the driving circuit and the second end of the driving circuit, so as to charge the energy storage circuit with the data voltage Vdata, and change a potential of the control end of the driving circuit until the potential of the control terminal of the driving circuit becomes Vdata+Vth, wherein Vth is a threshold voltage of the drive transistor included in the driving circuit;
in the light-emitting phase, under the control of the light-emitting control signal, controlling, by the light-emitting control circuit, to connect a first voltage line and the second end of the driving circuit, and connect the first end of the driving circuit and the first electrode of the light-emitting element, and driving, by the driving circuit, the light-emitting element to emit light.

### Claim 18 (depends on 1)

A display device comprising a pixel circuit according to claim 1,
wherein the pixel circuit comprises a reset circuit and a second initialization circuit, the reset circuit is electrically connected to the third scan line, and the second initialization circuit is connected to the fourth scan line, the display device further includes a third scan signal generation module and a fourth scan signal generation module;
the third scan signal generation module is electrically connected to the third scan line, and is configured to provide the third scan signal to the third scan line;
the fourth scan signal generation module is electrically connected to the fourth scan line, and is configured to provide the fourth scan signal to the fourth scan line,
wherein the third scan signal and the fourth scan signal are a same scan signal, and the third scan signal generation module and the fourth scan signal generation module are a same module.