Method and apparatus for controlling liquid crystal display brightness, and liquid crystal display device

• US 10,170,057 B2
• Filed: 06/05/2016
• Issued: 01/01/2019
• Est. Priority Date: 10/16/2015
• Status: Active Grant

• Current Assignee: Hisense Electric Co., Ltd. (Qingdao Huatong State-Owned Capital Operation (Group) Co., Ltd.), Hisense International Company Limited (Qingdao Huatong State-Owned Capital Operation (Group) Co., Ltd.), Hisense USA Corporation (Qingdao Huatong State-Owned Capital Operation (Group) Co., Ltd.)
• Original Assignee: Hisense Electric Co., Ltd. (Qingdao Huatong State-Owned Capital Operation (Group) Co., Ltd.), Hisense International Company Limited (Qingdao Huatong State-Owned Capital Operation (Group) Co., Ltd.), Hisense USA Corporation (Qingdao Huatong State-Owned Capital Operation (Group) Co., Ltd.)
• Inventors: Zhang, Yuxin, Huang, Shunming, Song, Zhicheng
• Primary Examiner(s): Lee, Nicholas
• Assistant Examiner(s): Pham Lu, Ngan T
• Application Number:
  US15/173,669
• Publication Number:
  US 20170110065A1
• Time in Patent Office: 940 Days
• Field of Search: 345690
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2320/066 for control of contrast
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2360/141 the light conveying information used for selecting or modulating the light emitting or modulating element
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 3/2018 by time modulation using two or more time intervals
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix
• CPC Class Codes: G09G 3/36 using liquid crystals

Abstract

This disclosure provides a method, and a liquid crystal display device, and relates to the field of liquid crystal display technologies, where the method includes: determining grayscale values of pixels in zone image data block under a predetermined rule according to a received image signal, and pre-obtaining a zone backlight value corresponding to the zone image data block according to the grayscale values in the zone image data block; determining a backlight gain coefficient according to a backlight value gain variable and an ambient luminance revision variable, and multiplying the zone backlight value with the backlight gain coefficient to obtain backlight values of a backlight zone corresponding to the zone image data block to which a gain is applied, wherein the backlight value gain variable is determined by the grayscale values, and the ambient luminance revision variable is determined by ambient luminance; and outputting the backlight value of the backlight zone to a driver circuit of backlight source in the backlight zone to control the brightness of the backlight source in the backlight zone as a result of driving, thus improving the effect of the contrast quality of pictures of the liquid crystal display device.

Claims

1. A method of controlling liquid crystal display brightness, the method comprising:

determining, by a liquid crystal display device, grayscale values of pixels in a zone image data block under a predetermined rule according to a received image signal, and pre-obtaining a zone backlight value corresponding to the zone image data block according to the grayscale values;

determining, by the liquid crystal display device, a backlight gain coefficient according to a backlight value gain variable and an ambient luminance revision variable, and multiplying, by the liquid crystal display device, the zone backlight value with the backlight gain coefficient to obtain a backlight value, to which a gain is applied, of a backlight zone corresponding to the zone image data block, wherein the backlight value gain variable is determined by the grayscale values, and the ambient luminance revision variable is determined by ambient luminance; and

outputting, by the liquid crystal display device, the backlight value, to which a gain is applied, of the backlight zone to a driver circuit of a backlight source in the backlight zone to control brightness of the backlight source in the backlight zone as a result of the driver circuit driving the backlight source.

2. The method according to claim 1, wherein a relationship between the ambient luminance revision variable and the ambient luminance is that the ambient luminance revision variable becomes larger with a larger ambient luminance value.

3. The method according to claim 1, wherein the ambient luminance revision variable is determined by dividing, by a liquid crystal display device, different ambient luminance values into several intervals, each of the intervals corresponding to a value of the ambient luminance revision variable.

4. The method according to claim 1, wherein the ambient luminance revision variable is determined by presetting, by the liquid crystal display device, a linear function relationship between an ambient luminance revision variable α

and an ambient luminance value E as α

₀+k*E, wherein α

₀ represents a constant, and k represents a variation rate at which the ambient luminance revision variable α

varies with the ambient luminance value E.

5. A liquid crystal display device comprising:

a backlight source driver circuit;

a backlight source;

at least one processor; and

a memory storing at least one instruction executable by the at least one processor to perform operations comprising;

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;

determining a backlight gain coefficient according to a backlight value gain variable and an ambient luminance revision variable, and multiplying the zone backlight value with the backlight gain coefficient to obtain a backlight value, to which a gain is applied, of a backlight zone corresponding to the zone image data block; and

outputting the backlight value, to which a gain is applied, of the backlight zone to a driver circuit of a backlight source in the backlight zone to control a brightness of the backlight source in the backlight zone as a result of the driver circuit driving the backlight source, wherein the backlight value gain variable is determined by the grayscale values, and the ambient luminance revision variable is determined by ambient luminance.

6. The device according to claim 5, wherein the operations further comprise determining the ambient luminance revision variable so that the ambient luminance revision variable becomes larger with a larger ambient luminance value.

7. The device according to claim 5, wherein the operations further comprise dividing different ambient luminance values into several intervals, each of the intervals corresponds to a value of the ambient luminance revision variable.

8. The device according to claim 5, wherein the operations further comprise determining a linear function relationship between an ambient luminance revision variable α

and an ambient luminance value E as α

₀+k*E, wherein α

₀ represents a constant, and k represents a variation rate at which the ambient luminance revision variable α

varies with the ambient luminance value E.

9. A liquid crystal device comprising:

a memory configured to store programs and various preset lookup table data;

an apparatus for controlling liquid crystal display brightness configured to execute the programs in the memory, and to invoke the various preset lookup table data according to the executed programs;

to receive an image signal, to process the data, and to output 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

to output a backlight value of a backlight zone to a backlight processing unit according to the image signal;

the backlight processing unit configured to determine duty ratio of a PWM signal according to the backlight value of the backlight zone, and to output the duty ratio to a PWM driver unit; and

the PWM driver unit configured to generate PWM control signal to control a backlight source in the backlight zone;

wherein the apparatus for controlling liquid crystal display brightness comprises;

a zone image grayscale determining section configured to determine grayscale values of pixels in a zone image data block under a predetermined rule according to the received image signal;

a zone backlight value pre-obtaining section configured to pre-obtain a zone backlight value corresponding to the zone image data block according to the grayscale values;

a zone backlight value gain section configured to determine a backlight gain coefficient according to a backlight value gain variable and an ambient luminance revision variable, and to multiply the zone backlight value with the backlight gain coefficient to obtain a backlight value, to which a gain is applied, of a backlight zone corresponding to the zone image data block to which a gain is applied, wherein the backlight value gain variable is determined by the grayscale values, and the ambient luminance revision variable is determined by ambient luminance; and

a zone backlight value outputting section configured to output the backlight value, to which a gain is applied, to a driver circuit of a backlight source in the backlight zone to control a brightness of the backlight source in the backlight zone as a result of the driver circuit driving the backlight source.

10. The device according to claim 9, wherein the zone backlight value gain section is configured to determine the ambient luminance revision variable so that the ambient luminance revision variable becomes larger with a larger ambient luminance value.

11. The device according to claim 9, wherein the zone backlight value gain section is configured to determine the ambient luminance revision variable by dividing different ambient luminance values into several intervals, each of the intervals corresponds to a value of the ambient luminance revision variable.

12. The device according to claim 9, wherein the zone backlight value gain section is configured to determine the ambient luminance revision variable by determining a linear function relationship between an ambient luminance revision variable α

and an ambient luminance value E as α

₀+k*E, wherein α

₀ represents a constant, and k represents a variation rate at which the ambient luminance revision variable α

varies with the ambient luminance value E.