Display apparatus and method of driving display panel using the same

Patent metadata

Field	Value
Publication number	US-11257435-B2
Application number	US-202016931509-A
Country	US
Kind code	B2
Filing date	Jul 17, 2020
Priority date	Aug 8, 2019
Publication date	Feb 22, 2022
Grant date	Feb 22, 2022

Abstract

A display apparatus includes a display panel, a gate driver, a data driver, and a driving controller. The display panel displays an image based on input image data. The gate driver outputs a gate signal to the display panel. The data driver outputs a data voltage to the display panel. The driving controller selectively determines a driving mode of the display apparatus between one of a normal driving mode and a low frequency driving mode, and determines a driving frequency of the display panel based on the input image data. The driving controller includes a flicker value storage storing flicker values for grayscale values of the input image data and a data remapper converting the grayscale value of the input image data to decrease a size of a maximum frequency grayscale area corresponding to a maximum driving frequency in the low frequency driving mode.

First claim

What is claimed is:

1. A display apparatus comprising:
a display panel configured to display an image based on input image data;
a gate driver configured to output a gate signal to the display panel;
a data driver configured to output a data voltage to the display panel; and
a driving controller configured to control an operation of the gate driver and an operation of the data driver, to selectively determine a driving mode of the display apparatus between a normal driving mode and a low frequency driving mode, and to determine a driving frequency of the display panel based on the input image data,
wherein the driving controller comprises:
a flicker value storage configured to store flicker values for grayscale values of the input image data; and
a data remapper configured to convert the grayscale value of the input image data to decrease a size of a maximum frequency grayscale area corresponding to a maximum driving frequency in the low frequency driving mode,
wherein grayscale values in the maximum frequency grayscale area are driven in the maximum driving frequency in the low frequency driving mode.

2. The display apparatus of claim 1 , wherein the driving controller further comprises:
a still image determiner configured to determine whether the input image data is a still image or a video image based on the input image data, and configured to generate a flag representing whether the input image data is the still image or the video image; and
a driving frequency determiner configured to selectively determine the driving mode of the display apparatus between the normal driving mode and the low frequency driving mode based on the flag, and configured to determine the driving frequency of the display panel using the flicker value storage.

3. The display apparatus of claim 2 , wherein the data remapper is configured to convert the grayscale value of the input image data when the input image data is the still image, and
wherein the data remapper is configured not to convert the grayscale value of the input image data when the input image data is the video image.

4. The display apparatus of claim 3 , wherein the data remapper includes a data remapping lookup table configured to generate a converted grayscale value by multiplying a converting gain to the grayscale value of the input image data.

5. The display apparatus of claim 4 , wherein the flicker value storage and the data remapping lookup table are formed in a same memory.

6. The display apparatus of claim 3 , wherein the data remapper is configured to receive the flag and the grayscale value of the input image data from the still image determiner, configured to multiply a converting gain to the grayscale value of the input image data to generate a converted grayscale value, and configured to output the converted grayscale value to the driving frequency determiner.

7. The display apparatus of claim 6 , wherein the data remapper is configured to extract a luminance component from the grayscale value of the input image data, configured to multiply a luminance compensating gain to the extracted luminance component of the input image data to generate a compensated luminance component, and configured to generate the converted grayscale value based on the compensated luminance component.

8. The display apparatus of claim 2 , wherein the driving controller further comprises a fixed frequency determiner configured to determine whether an input frequency of the input image data has a normal type by counting a number of pulses of a horizontal synchronizing signal between a first pulse and a second pulse of a vertical synchronizing signal or by counting a number of pulses of a data enable signal between the first pulse and the second pulse of the vertical synchronizing signal.

9. The display apparatus of claim 8 , wherein the fixed frequency determiner is configured to generate a frequency flag representing whether the input frequency of the input image data has the normal type or not, and
wherein the driving frequency determiner is configured to determine the driving frequency of the display panel.

10. The display apparatus of claim 1 , wherein the maximum frequency grayscale area is defined as an area equal to or greater than a first grayscale value and equal to or less than a second grayscale value,
wherein a converted maximum frequency grayscale area which is converted by the driving controller is defined as an area equal to or greater than a third grayscale value and equal to or less than a fourth grayscale value,
wherein the third grayscale value is greater than the first grayscale value, and
wherein the fourth grayscale value is less than the second grayscale value.

11. The display apparatus of claim 10 , wherein a converting gain to generate the converted maximum frequency grayscale area is less than 1 in a first converting area and greater than 1 in a second converting area.

12. The display apparatus of claim 1 , wherein the maximum frequency grayscale area is defined as an area equal to or greater than a first grayscale value,
wherein a converted maximum frequency grayscale area which is converted by the driving controller is defined as an area equal to or greater than a second grayscale value, and
wherein the second grayscale value is greater than the first grayscale value.

13. The display apparatus of claim 12 , wherein a converting gain to generate the converted maximum frequency grayscale area is equal to or less than 1.

14. The display apparatus of claim 1 , wherein the display panel comprises a plurality of segments in a matrix form, and
wherein the driving controller is configured to determine the driving frequency of the display panel based on optimal driving frequencies for the segments.

15. A method of driving a display panel, the method comprising:
selectively determining a driving mode of a display apparatus between a normal driving mode and a low frequency driving mode;
converting a grayscale value of input image data to decrease a size of a maximum frequency grayscale area corresponding to a maximum driving frequency in the low frequency driving mode;
determining a driving frequency of the display panel using a flicker value storage configured to store a flicker value for the grayscale value of the input image data;
outputting a gate signal to the display panel based on the driving frequency; and
outputting a data voltage to the display panel based on the driving frequency,
wherein grayscale values in the maximum frequency grayscale area are driven in the maximum driving frequency in the low frequency driving mode.

16. The method of claim 15 , wherein the determining the driving frequency comprises:
selectively determining whether the input image data is a still image or a video image;
generating a flag representing whether the input image data is the still image or the video image;
selectively determining the driving mode of the display apparatus between the normal driving mode and the low frequency driving mode based on the flag; and
determining the driving frequency of the display panel using the flicker value storage.

17. The method of claim 16 , wherein the grayscale value of the input image data is converted when the input image data is the still image, and
wherein the grayscale value of the input image data is not converted when the input image data is the video image.

18. The method of claim 17 , wherein the converting the grayscale value of input image data comprises generating a converted grayscale value by multiplying a converting gain to the

Assignees

• Samsung Display Co Ltd

Inventors

• Kim Hongsoo
• Park Sehyuk
• Kwon Sangan
• Roh Jinyoung
• Lee Sukhun
• Lee Hyojin
• Jung Junheyung

Classifications

• G09G3/3225 Primary

  using an active matrix · CPC title

• G09G3/3233 Primary

  with pixel circuitry controlling the current through the light-emitting element · CPC title

• G09G2320/0247

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

• G09G2330/021

  Power management, e.g. power saving · CPC title

• G09G2300/0819

  used for counteracting undesired variations, e.g. feedback or autozeroing · CPC title