Backlight brightness adjusting method and device, and liquid crystal display device

• US 9,747,844 B2
• Filed: 06/22/2015
• Issued: 08/29/2017
• Est. Priority Date: 03/05/2015
• Status: Active Grant

• Current Assignee: Hisense International Company Limited (Qingdao Huatong State-Owned Capital Operation Company Limited), Hisense USA Corporation (Qingdao Huatong State-Owned Capital Operation Company Limited)
• Original Assignee: Hisense Electric Co., Ltd. (Qingdao Huatong State-Owned Capital Operation Company Limited), Hisense International Company Limited (Qingdao Huatong State-Owned Capital Operation Company Limited), Hisense USA Corporation (Qingdao Huatong State-Owned Capital Operation Company Limited)
• Inventors: Diao, Yujie, Yang, Jia, Huang, Shunming
• Primary Examiner(s): Tzeng, Fred
• Application Number:
  US14/745,751
• Publication Number:
  US 20160260390A1
• Time in Patent Office: 799 Days
• Field of Search: 345691
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336

Abstract

The disclosure discloses a backlight brightness adjusting method and device and a liquid crystal display device. In the backlight brightness adjusting method, grayscale characteristic values of respective primary colors in an image to be displayed are obtained, that is, contributions of the respective primary colors to an overall grayscale are obtained, to thereby obtain the grayscale contributions of the respective primary colors in the image to be displayed respectively; a backlight value is determined by giving different coefficients to the grayscale characteristic values of the respective primary colors; and finally an output of a backlight driver is adjusted according to the backlight value to thereby adjust backlight brightness.

Claims

1. A backlight brightness adjusting method for a liquid crystal display device, the method comprising:

obtaining grayscale characteristic values of respective primary colors in an image to be displayed, the grayscale characteristic values of the respective primary colors characterizing contributions of grayscales of the respective primary colors to a grayscale of the image to be displayed;

determining a first product of a red one of the grayscale characteristic values and a first coefficient corresponding to a red color, determining a second product of a green one of the grayscale characteristic values and a second coefficient corresponding to a green color, and determining a third product of a blue one of the grayscale characteristic values and a third coefficient corresponding to a blue color;

summing the first product, the second product and the third product to obtain the backlight value; and

adjusting a backlight brightness according to the backlight value.

2. The method according to claim 1, wherein summing the first product, the second product, and the third product to obtain the backlight value comprises:

calculating the sum of the first product, the second product, and the third product; and

setting the backlight value to the sum of the first product, the second product, and the third product when the sum of the first product, the second product, and the third product is no more than 255.

3. The method according to claim 2, wherein the first coefficient is larger than the second coefficient.

4. The method according to claim 1, wherein obtaining the grayscale characteristic values of the respective primary colors in the image to be displayed comprises:

obtaining grayscales of respective pixels in the image to be displayed;

determining first grayscales and grayscale proportions of the respective primary colors in the image to be displayed according to the grayscales of the respective pixels; and

determining the grayscale characteristic values of the respective primary colors according to the products of the first grayscales and the grayscale proportions of the respective primary colors.

5. The method according to claim 4, wherein determining the first grayscales of the respective primary colors in the image to be displayed according to the grayscales of the respective pixels comprises:

determining a red first grayscale in the image to be displayed according to red grayscales of the respective pixels;

determining a green first grayscale in the image to be displayed according to green grayscales of the respective pixels; and

determining a blue first grayscale in the image to be displayed according to blue grayscales of the respective pixels.

6. The method according to claim 5, wherein determining the red first grayscale in the image to be displayed according to the red grayscales of the respective pixels comprises:

calculating an average of red grayscales of all pixels in the image to be displayed, and weighted summing up a maximum of the red grayscales of all the pixels in the image to be displayed and the average of the red grayscales of all the pixels in the image to be displayed to obtain the red first grayscale in the image to be displayed;

determining the green first grayscale in the image to be displayed according to the green grayscales of the respective pixels comprises;

calculating an average of the green grayscales of all the pixels in the image to be displayed, and weighted summing up a maximum of the green grayscales of all the pixels in the image to be displayed and the average of the green grayscales of all the pixels in the image to be displayed to obtain the green first grayscale in the image to be displayed; and

determining the blue first grayscale in the image to be displayed according to the blue grayscales of the respective pixels comprises;

calculating an average of the blue grayscales of all the pixels in the image to be displayed, and weighted summing up a maximum of the blue grayscales of all the pixels in the image to be displayed and the average of the blue grayscales of all the pixels in the image to be displayed to obtain the blue first grayscale in the image to be displayed.

7. The method according to claim 4, wherein determining the grayscale proportions of the respective primary colors in the image to be displayed according to the grayscales of the respective pixels comprises:

summing up red grayscales of the respective pixels in the image to be displayed to obtain a sum of the red grayscales of all pixels R₁, summing up green grayscales of the respective pixels in the image to be displayed to obtain a sum of the green grayscales of all the pixels G₁, and summing up blue grayscales of the respective pixels in the image to be displayed to obtain a sum of the blue grayscales of all the pixels B₁; and

determining a red grayscale proportion R, a green grayscale proportion G, and a blue grayscale proportion B corresponding to the image to be displayed respectively in the equations of

8. A backlight brightness adjusting device for a liquid crystal display device, the backlight brightness adjusting device comprising:

a memory; and

one or more processors, the memory storing one or more computer readable program codes, and the one or more processors configured to execute the one or more computer readable program codes to perform;

obtaining grayscale characteristic values of respective primary colors in an image to be displayed, the grayscale characteristic values of the respective primary colors characterizing contributions of grayscales of the respective primary colors to a grayscale of the image to be displayed;

determining a first product of a red one of the grayscale characteristic values and a first coefficient corresponding to a red color, determining a second product of a green one of the grayscale characteristic values and a second coefficient corresponding to a green color, and determining a third product of a blue one of the grayscale characteristic values and a third coefficient corresponding to a blue color;

summing the first product, the second product and the third product to obtain the backlight value; and

adjusting a backlight brightness according to the backlight value.

9. The backlight brightness adjusting device according to claim 8, wherein summing the first product, the second product, and the third product to obtain the backlight value comprises:

calculating the sum of the first product, the second product, and the third product; and

setting the backlight value to the sum of the first product, the second product, and the third product when the sum of the first product, the second product, and the third product is no more than 255.

10. The backlight brightness adjusting device according to claim 9, wherein the first coefficient is larger than the second coefficient.

11. The backlight brightness adjusting device according to claim 8, wherein obtaining the grayscale characteristic values of the respective primary colors in the image to be displayed comprises:

obtaining grayscales of respective pixels in the image to be displayed;

determining first grayscales and grayscale proportions of the respective primary colors in the image to be displayed according to the grayscales of the respective pixels; and

determining the grayscale characteristic values of the respective primary colors according to the products of the first grayscales and the grayscale proportions of the respective primary colors.

12. The backlight brightness adjusting device according to claim 11, wherein determining the first grayscales of the respective primary colors in the image to be displayed according to the grayscales of the respective pixels comprises:

determining a red first grayscale in the image to be displayed according to red grayscales of the respective pixels;

determining a green first grayscale in the image to be displayed according to green grayscales of the respective pixels; and

determining a blue first grayscale in the image to be displayed according to blue grayscales of the respective pixels.

13. The backlight brightness adjusting device according to claim 12, wherein determining the red first grayscale in the image to be displayed according to the red grayscales of the respective pixels comprises:

calculating an average of red grayscales of all pixels in the image to be displayed, and weighted summing up a maximum of the red grayscales of all the pixels in the image to be displayed and the average of the red grayscales of all the pixels in the image to be displayed to obtain the red first grayscale in the image to be displayed;

determining the green first grayscale in the image to be displayed according to the green grayscales of the respective pixels comprises;

calculating an average of the green grayscales of all the pixels in the image to be displayed, and weighted summing up a maximum of the green grayscales of all the pixels in the image to be displayed and the average of the green grayscales of all the pixels in the image to be displayed to obtain the green first grayscale in the image to be displayed; and

determining the blue first grayscale in the image to be displayed according to the blue grayscales of the respective pixels comprises;

calculating an average of the blue grayscales of all the pixels in the image to be displayed, and weighted summing up a maximum of the blue grayscales of all the pixels in the image to be displayed and the average of the blue grayscales of all the pixels in the image to be displayed to obtain the blue first grayscale in the image to be displayed.

14. The backlight brightness adjusting device according to claim 11, wherein determining the grayscale proportions of the respective primary colors in the image to be displayed according to the grayscales of the respective pixels comprises:

summing up red grayscales of the respective pixels in the image to be displayed to obtain a sum of the red grayscales of all pixels R₁, summing up green grayscales of the respective pixels in the image to be displayed to obtain a sum of the green grayscales of all the pixels G₁, and summing up blue grayscales of the respective pixels in the image to be displayed to obtain a sum of the blue grayscales of all the pixels B₁; and

determining a red grayscale proportion R, a green grayscale proportion G, and a blue grayscale proportion B corresponding to the image to be displayed respectively in the equations of

15. A liquid crystal display device comprising:

a backlight brightness adjusting device, the backlight brightness adjusting device comprising;

a memory; and

one or more processors, the memory storing one or more computer readable program codes, the one or more processors configured to execute the one or more computer readable program codes to perform;

obtaining grayscale characteristic values of respective primary colors in an image to be displayed, the grayscale characteristic values of the respective primary colors characterizing contributions of grayscales of the respective primary colors to a grayscale of the image to be displayed;

determining a first product of a red one of the grayscale characteristic values and a first coefficient corresponding to a red color, determining a second product of a green one of the grayscale characteristic values and a second coefficient corresponding to a green color, and determining a third product of a blue one of the grayscale characteristic values and a third coefficient corresponding to a blue color;

summing the first product, the second product and the third product to obtain the backlight value; and

adjusting a backlight brightness according to the backlight value.

16. The liquid crystal display device according to claim 15, wherein summing up the first product, the second product, and the third product to obtain the backlight value comprises:

calculating the sum of the first product, the second product, and the third product; and

setting the backlight value to the sum of the first product, the second product, and the third product when the sum of the first product, the second product, and the third product is no more than 255.

17. The liquid crystal display device according to claim 16, wherein the first coefficient is larger than the second coefficient.