# US 2018/0322844 A1 · Display device

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- Number: US 2018/0322844 A1
- Document ID: US20180322844A1
- Status: Published application
- Kind: A1
- Application number: 15/935,812
- Filed: 2018-03-26
- Published: 2018-11-08
- Earliest claimed: 2017-05-08
- Assignees: Samsung Display Co., Ltd.
- Applicants: Samsung Display Co., Ltd.
- Inventors: Jae Hoon LEE; Jai Hyun KOH; Heen Dol KIM; Bong Hyun YOU; Soo Yeon LEE; Seok Ha HONG
- Web page: https://patentgrep.com/patent/US20180322844A1

## CPC

- G09G 3/3696: {Generation of voltages supplied to electrode drivers}
- G09G 5/10: Intensity circuits
- G09G 2300/0413: Details of dummy pixels or dummy lines in flat panels
- G09G 2320/0247: Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
- G09G 2320/029: by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel
- 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)

## Abstract

A display device may include display pixels configured to emit light at a luminance corresponding to a data signal, at least one auxiliary pixel configured to store an auxiliary voltage, a gate driver configured to supply a gate signal to the display pixels and the auxiliary pixel, a data driver configured to convert image data into the data signal, and supply an auxiliary voltage having a preset level to the auxiliary pixel. A sensing circuit is configured to sense a change in the auxiliary pixel for each frame, and generate compensation voltage information. A timing controller is configured to convert an image signal into the image data, and generate a driving voltage control signal. A voltage generation unit is configured to generate a driving voltage corresponding to the driving voltage control signal, and generate the reference gamma voltage based on the driving voltage.

## Claims

### Claim 1

A display device comprising:
a plurality of display pixels configured to emit light at a luminance corresponding to a data signal;
at least one auxiliary pixel configured to store an auxiliary voltage;
a gate driver configured to supply a gate signal to the plurality of display pixels and the at least one auxiliary pixel;
a data driver configured to convert image data into the data signal using a reference gamma voltage, and supply an auxiliary voltage having a preset value to the at least one auxiliary pixel;
a sensing circuit configured to sense whether a change occurs in the preset value of the auxiliary voltage stored in the auxiliary pixel for a predetermined period, and to generate compensation voltage information;
a timing controller configured to convert an image signal inputted from an external device into the image data, and generate a driving voltage control signal that controls a driving voltage in correspondence with the compensation voltage information; and
a voltage generation unit configured to generate a driving voltage corresponding to the driving voltage control signal received from the timing controller, and to generate the reference gamma voltage based on the driving voltage.

### Claim 2 (depends on 1)

The display device according to claim 1, wherein the predetermined period comprises a per-frame basis.

### Claim 3 (depends on 2)

The display device according to claim 2, wherein, when the compensation voltage information includes a difference value between a first auxiliary voltage measured during a current frame and a reference auxiliary voltage, the driving voltage control signal generated by the timing controller controls the voltage generation unit to increase the driving voltage in correspondence with the difference value.

### Claim 4 (depends on 2)

The display device according to claim 2, wherein, when the compensation voltage information includes a difference value between a first auxiliary voltage measured during a current frame and a second auxiliary voltage measured during a preceding frame, and the first auxiliary voltage is less than the second auxiliary voltage, the driving voltage control signal generated by the timing controller controls the voltage generation unit to increase the driving voltage in correspondence with the difference value.

### Claim 5 (depends on 4)

The display device according to claim 4, wherein the voltage generation unit generates an increased driving voltage for a subsequent frame.

### Claim 6 (depends on 1)

The display device according to claim 1, wherein, when the compensation voltage information includes a difference value between a first auxiliary voltage measured during a current frame and a second auxiliary voltage measured during a preceding frame, the first auxiliary voltage is less than the second auxiliary voltage, and the difference value is greater than a threshold difference value, the driving voltage control signal generated by the timing controller controls the voltage generation unit to increase the driving voltage in correspondence with the difference value.

### Claim 7 (depends on 1)

The display device according to claim 1, wherein the sensing circuit comprises:
an output sensing unit configured to measure the auxiliary voltage stored in the at least one auxiliary pixel using a leakage current outputted from the at least one auxiliary pixel; and
a compensation unit configured to generate the compensation voltage information based on a change in the measured auxiliary voltage.

### Claim 8 (depends on 1)

The display device according to claim 1, wherein the at least one auxiliary pixel comprises:
a first transistor including a gate electrode coupled to an i-th gate line, a first electrode coupled to a first node, and a second electrode electrically coupled to the sensing circuit through a read-out line;
a second transistor including a gate electrode coupled to an i+1-th gate line, a first electrode coupled to the first node, and a second electrode coupled to an auxiliary data line; and
an auxiliary capacitor coupled to the first node and configured to store the auxiliary voltage.

### Claim 9 (depends on 8)

The display device according to claim 8, wherein the auxiliary capacitor stores the auxiliary voltage supplied to the first node from the auxiliary data line while the second transistor is turned on.

### Claim 10 (depends on 1)

The display device according to claim 1, wherein the plurality of display pixels and the at least one auxiliary pixel are disposed on different horizontal lines.

### Claim 11 (depends on 1)

The display device according to claim 1,
wherein the gate driver comprises first and second gate drivers, and
wherein the first gate driver is coupled to the plurality of display pixels through a first gate line, and the second gate driver is coupled to the at least one auxiliary pixel through a second gate line different from the first gate line.

### Claim 12 (depends on 1)

The display device according to claim 1, wherein the plurality of display pixels are disposed on a display area in which an image is displayed, and the at least one auxiliary pixel is disposed on a non-display area in which an image is not displayed.

### Claim 13 (depends on 1)

The display device according to claim 1, wherein a period in which the data signal is supplied to at least some of the plurality of display pixels does not overlap a period in which the auxiliary voltage is supplied to the at least one auxiliary pixel.

### Claim 14

A display device comprising:
a plurality of display pixels configured to emit light at a luminance corresponding to a data signal;
at least one auxiliary pixel configured to store an auxiliary voltage;
a gate driver configured to supply a gate signal to the plurality of display pixels and the at least one auxiliary pixel;
a sensing circuit configured to sense a change in the auxiliary voltage stored in the at least one auxiliary pixel for each frame, and to generate compensation voltage is information;
a timing controller configured to change a gradation of an image signal inputted from an external device according to the compensation voltage information generated by the sensing circuit, and to generate image data; and
a data driver configured to convert the image data into the data signal, and supply an auxiliary voltage having a preset value to the at least one auxiliary pixel.

### Claim 15 (depends on 14)

The display device according to claim 14,
wherein the sensing circuit generates first auxiliary voltage information using an auxiliary pixel coupled to i-th and i+1-th gate lines, and
wherein the timing controller generates the image data by changing a gradation of the image signal corresponding to the plurality of display pixels coupled to the i-th and i+1-th gate lines according to the first auxiliary voltage information.

### Claim 16 (depends on 15)

The display device according to claim 15, wherein the timing controller generates image data of an R_DATA, G_DATA and B_DATA having a changed gradation by changing bits of image signals R, G and B that are digital signals.

### Claim 17

A method for preventing flicker in a liquid crystal display device, the method including:
providing in a display area of the liquid crystal display device, a plurality of display pixels that emit light at a luminance corresponding to a data signal of a current frame, and in at least one of a non-display area and display area of the liquid crystal display device, at least one auxiliary pixel that stores an auxiliary voltage;
converting an image signal inputted from an external device into image data, and generating a driving voltage control signal that controls a driving voltage in correspondence with a compensation voltage information provided by a sensing circuit that is connected at least with the at least one auxiliary pixel and a timing controller;
comparing a leakage current of at least one auxiliary pixel during a previous frame with a leakage current of the current frame, in which the auxiliary pixel is configured to store an auxiliary voltage; and
adjusting a compensation voltage that is applied to a voltage generation unit, when the comparing of the leakage current indicates that the luminance of the plurality of the display pixels is outside of a threshold range.

### Claim 18 (depends on 17)

The method according to claim 17, wherein the adjusting of the compensation voltage occurs in real time during a frame.

### Claim 19 (depends on 17)

The method according to claim 17, wherein the compensation voltage restores the luminance of the plurality of display pixels to a value initially specified by the data signal of the current frame.

### Claim 20 (depends on 17)

A non-transitory computer readable storage medium including executable code when executed by a processor of a liquid crystal display device performs the method of claim 17.
