Apparatus and method for controlling liquid crystal display brightness, and liquid crystal display device

Patent metadata

Field	Value
Publication number	US-10269308-B2
Application number	US-201615158759-A
Country	US
Kind code	B2
Filing date	May 19, 2016
Priority date	Sep 17, 2015
Publication date	Apr 23, 2019
Grant date	Apr 23, 2019

Abstract

The disclosure provides an apparatus and method for controlling liquid crystal display brightness, and a liquid crystal display device, where the method includes: determining grayscale values of pixels in a zone image data block under a predetermined rule according to a received image signal; pre-obtaining a zone backlight value corresponding to the zone image data block according to the grayscale values in the zone image data block; multiplying the pre-obtained a zone backlight value with a backlight value gain coefficient to obtain a backlight value to which a gain is applied of a backlight zone, wherein the backlight value gain coefficient is more than 1; and mapping the respective zone backlight values to driver circuits of backlight sources in the corresponding backlight zones.

First claim

The invention claimed is:

1. A method for controlling brightness of a liquid crystal display, the method comprising:
determining grayscale values of pixels in a zone image data block under a predetermined rule according to a received image signal, wherein the predetermined rule includes a pre-stored function model in which the liquid crystal display is divided into a number of virtual zones at the same proportion as backlight zones and image data of all pixels displayed in one of the virtual zones are aggregated into the zone image data block;
pre-obtaining a zone backlight value corresponding to the zone image data block according to the determined grayscale values of the pixels in the zone image data block;
multiplying the pre-obtained zone backlight value with a backlight value gain coefficient to obtain a gained backlight value of a backlight zone corresponding to the zone image data block, wherein the backlight value gain coefficient is greater than 1 to enhance a zone peak brightness corresponding to the zone image data block;
when it is determined that an average grayscale value of pixels in a zone image data block cluster is below a first threshold, multiplying the gained backlight value with a revision coefficient determined according to a dispersity of image brightness distribution of the zone image data block cluster, wherein multiple zone image data blocks including said zone image data block are divided into multiple zone image data block clusters including said data block cluster, each of the zone image data block clusters comprises a number of adjacent ones of the zone image data blocks, and the revision coefficient is less than 1; and
outputting the gained backlight value to a driver circuit of a backlight source in the backlight zone to control brightness of the backlight source in the backlight zone.

2. The method of claim 1 , wherein after multiplying the pre-obtained zone backlight value with the backlight value gain coefficient to obtain the gained backlight value of the backlight zone, the method further comprises:
when it is determined that an average grayscale value of the pixels in the zone image data block is below the first threshold, multiplying the gained backlight value with a revision coefficient determined according to a dispersity of image brightness distribution of the zone image data block, wherein the revision coefficient is less than 1.

3. The method of claim 2 , wherein the revision coefficient determined according to the dispersity of image brightness distribution of the zone image data block and the dispersity of image brightness distribution of the zone image data block have an inverse correspondence relationship where a smaller revision coefficient corresponds to a larger dispersity of image brightness distribution.

4. The method of claim 1 , wherein after multiplying the pre-obtained zone backlight value with the backlight value gain coefficient to obtain the gained backlight value of the backlight zone, the method further comprises:
when it is determined that an average grayscale value of pixels in an image comprising the zone image data block is below the first threshold, multiplying the gained backlight value with a revision coefficient determined according to a dispersity of image brightness distribution of the image;
wherein the revision coefficient determined according to the dispersity of image brightness distribution of the image is less than 1, and the revision coefficient determined according to the dispersity of image brightness distribution of the image and the dispersity of image brightness distribution of the image have an inverse correspondence relationship where a smaller revision coefficient corresponds to a larger dispersity of image brightness distribution.

5. The method of claim 4 , wherein the backlight value gain coefficient is obtained by:
obtaining an average grayscale value of pixels in the image from grayscale values of pixels in the image; and
determining the backlight value gain coefficient according to a correspondence relationship between the average grayscale value of the pixels in the image and the backlight value gain coefficient.

6. The method of claim 1 , wherein
the revision coefficient and the dispersity of image brightness distribution have an inverse correspondence relationship where a smaller revision coefficient corresponds to a larger dispersity of image brightness distribution.

7. The method of claim 6 , wherein the backlight value gain coefficient is obtained by:
obtaining the average grayscale value of all pixels in the zone image data block cluster, and
determining the backlight value gain coefficient according to a relationship between the average grayscale value and the backlight value gain coefficient.

8. A liquid crystal display device, comprising:
a memory configured to store programs and various preset lookup table data;
an apparatus for controlling brightness of a liquid crystal display; the apparatus configured to:
execute the programs stored in the memory, and invoke the various lookup table data according to the executed programs;
receive an image signal, process image data, and output the image data to a timing controller so that the timing controller generates a driver signal according to the image data to control a liquid crystal panel to display an image; and
output zone backlight values to a backlight processing component according to the image signal;
the backlight processing component configured to determine duty ratios of corresponding PWM signals according to the zone backlight values, and to output the duty ratios to a PWM driver component; and
the PWM driver component configured to generate PWM control signals to control backlight sources in backlight zones;
wherein the apparatus for controlling brightness of the liquid crystal display includes a memory and one or more processors, wherein one or more computer readable program codes are stored in the memory, and the one or more processors are configured to execute the one or more computer readable program codes to perform:
determining grayscale values in a zone image data block under a predetermined rule according to a received image signal, wherein the predetermined rule includes a pre-stored function model in which the liquid crystal panel is divided into a number of virtual zones at the same proportion as the backlight zones and the image data of all pixels displayed in one of the virtual zones are aggregated into the zone image data block;
pre-obtaining a zone backlight value corresponding to the zone image data block according to the determined grayscale values of the pixels in the zone image data block;
multiplying the pre-obtained zone backlight value with a backlight value gain coefficient to obtain a gained backlight value of a backlight zone corresponding to the zone image data block, wherein the backlight value gain coefficient is greater than 1 to enhance a zone peak brightness corresponding to the zone image data block;
when it is determined that an average grayscale value of pixels in an image comprising the zone image data block is below a first threshold, multiplying the gained backlight value with a revision coefficient determined according to a dispersity of image brightness distribution of the image, wherein the revision coefficient is less than 1;
outputting the gained backlight value to a driver circuit of a backlight source in the backlight zone to control brightness of the backlight source in the backlight zone.

9. The liquid crystal display device of claim 8 , wherein the one or more processors are further configured to execute the one or more computer readable program codes to perform:
when it is determined that an average graysca

Assignees

• Hisense Electric Co Ltd
• Hisense Usa Corp
• Hisense Int Co Ltd

Inventors

• Yang Jia
• Zhang Yuxin
• Huang Shunming
• Diao Yujie

Classifications

• G09G3/3648

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

• G09G2320/0626

  for control of overall brightness · CPC title

• G09G2330/021

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

• G09G3/3426 Primary

  the different display panel areas being distributed in two dimensions, e.g. matrix · CPC title

• G09G2360/16

  Calculation or use of calculated indices related to luminance levels in display data · CPC title