Display device which prevents occurrence of flicker

Patent metadata

Field	Value
Publication number	US-9940886-B2
Application number	US-201414511755-A
Country	US
Kind code	B2
Filing date	Oct 10, 2014
Priority date	Oct 10, 2013
Publication date	Apr 10, 2018
Grant date	Apr 10, 2018

Abstract

A display device which prevents or minimizes the occurrence of flicker is provided. The display device includes a display panel having pixels, with data lines and gate lines that are respectively connected with the pixels. A display driving circuit is configured to vary a frame frequency of the display panel according to an operation mode, to select a gamma curve corresponding to the frame frequency. The selected gamma curve is one among gamma curves that are set so as to correspond to different frame frequencies. The display panel is driven based on the selected gamma curve.

First claim

What is claimed is:

1. A display device comprising:
a display panel comprising:
a plurality of pixels, and
a plurality of data lines and a plurality of gate lines that are respectively connected with the plurality of pixels; and

a display driving circuit configured to:
set a frame frequency corresponding to the display panel according to an operation mode,
select a gamma curve corresponding to the frame frequency from among a plurality of gamma curves that are set so as to correspond to different frame frequencies, and
drive the display panel based on the selected gamma curve and the frame frequency,

wherein the display driving circuit drops a level of a gate-on voltage from a first voltage level to a second voltage level according to a kickback signal to adjust a falling slew rate of a gate signal.

2. The display device of claim 1 , wherein the display driving circuit is further configured to:
store a first gamma selection signal and a second gamma selection signal that correspond to different gamma curves, respectively, and
select one of the first gamma selection signal and the second gamma selection signal as a gamma control signal, according to the frame frequency.

3. The display device of claim 1 ,
wherein the plurality of gamma curves comprises:
a first gamma curve that corresponds to a first frame frequency, and
a second gamma curve that corresponds to a second frame frequency that is lower than the first frame frequency, and

wherein grayscale voltages of the second gamma curve are lower than grayscale voltages of the first gamma curve.

4. The display device of claim 1 ,
wherein, during a moving image mode, the display driving circuit displays a moving image received from an external source on the display panel, based on a first frame frequency, and
wherein, during a still image mode, the display driving circuit displays a still image stored in an internal frame memory on the display panel, based on a second frame frequency that is lower than the first frame frequency.

5. The display device of claim 4 ,
wherein, during the moving image mode, the display driving circuit generates a display synchronization signal having the first frame frequency, based on a control signal and an external clock signal that are provided from the external source, and
wherein, during the still image mode, the display driving circuit generates a display synchronization signal having the second frame frequency, based on an internal clock signal.

6. The display device of claim 1 , wherein the display driving circuit is configured to adjust the falling slew rate of a gate signal that is provided to each of the plurality of gate lines, according to the frame frequency.

7. The display device of claim 6 ,
wherein the display driving circuit is configured to generate the gate signal by using the gate-on voltage and a gate-off voltage, and
wherein, when the frame frequency is equal to or lower than a reference value, the display driving circuit periodically drops the level of the gate-on voltage.

8. The display device of claim 1 , further comprising:
a host controller configured to provide image data and an operation mode signal for indicating the operation mode to the display driving circuit.

9. The display device of claim 8 ,
wherein, when the image data is a moving image, the host controller provides a first operation mode signal indicating a moving image mode to the display driving circuit, and
wherein, when the image data is a still image, the host controller provides a second operation mode signal indicating a still image mode to the display driving circuit.

10. The display device of claim 8 , wherein, during a power-on or initial setting of the display device, the host controller provides a plurality of gamma selection signals that correspond to the plurality of gamma curves, respectively, to the display driving circuit.

11. The display device of claim 1 , wherein the display panel comprises an oxide thin film transistor substrate in which each of the plurality of pixels comprises an oxide thin film transistor.

Assignees

• Samsung Electronics Co Ltd

Inventors

• Lee Hong-Kook
• Kim Dong-Sub
• Shin Hyun-Chang

Classifications

• G09G3/3648 Primary

  using an active matrix (G09G3/367 - G09G3/3696 take precedence) · CPC title

• G09G2320/103

  Detection of image changes, e.g. determination of an index representative of the image change · CPC title

• G09G2320/0626

  for control of overall brightness · CPC title

• G09G2340/0435

  Change or adaptation of the frame rate of the video stream · CPC title

• G09G2320/0247

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