Display device

Patent metadata

Field	Value
Publication number	US-2018322844-A1
Application number	US-201815935812-A
Country	US
Kind code	A1
Filing date	Mar 26, 2018
Priority date	May 8, 2017
Publication date	Nov 8, 2018
Grant date	—

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.

First claim

What is claimed is:

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.

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

3 . 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.

4 . 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.

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

6 . 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.

7 . 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.

8 . 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.

9 . 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.

10 . 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.

11 . 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.

12 . 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.

13 . 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.

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.

15 . 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.

16 . 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.

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 contr

Assignees

• Samsung Display Co Ltd

Inventors

• Lee Jae Hoon
• Koh Jai Hyun
• Kim Heen Dol
• You Bong Hyun
• Lee Soo Yeon
• Hong Seok Ha

Classifications

• G09G2320/0247

  Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes · CPC title

• G09G2300/0413

  Details of dummy pixels or dummy lines in flat panels · CPC title

• G09G3/3696 Primary

  Generation of voltages supplied to electrode drivers · CPC title

• G09G2320/029

  by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel · CPC title

• G09G5/10

  Intensity circuits · CPC title