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

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

determining, by a processor, 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, by the processor, a backlight gain coefficient according to a backlight value gain variable and an ambient luminance revision variable;

multiplying, by the processor, the zone backlight value with the backlight gain coefficient, to obtain an adjusted backlight value 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;

outputting, by the processor, the adjusted backlight value of the backlight zone to a driver circuit of a backlight source in the backlight zone; and

driving the backlight source, by the driver circuit, according to the adjusted backlight value to control brightness of the backlight source in the backlight zone.

2. The method according to claim 1 , wherein the determining a backlight gain coefficient, by the processor, according to a backlight value gain variable and an ambient luminance revision variable comprises:

searching, by the processor, a preset two-dimension variable lookup table between a backlight value gain variable and a ambient luminance revision variable for the backlight gain coefficient using determined backlight value gain variable and determined ambient luminance revision variable.

3. The method according to claim 1 , wherein calculating, by the processor, an adjusted backlight value of a backlight zone corresponding to the zone image data block, based on the zone backlight value, a backlight value gain variable and an ambient luminance revision variable comprises:

multiplying the zone backlight value by a summation of a backlight value gain variable and an ambient luminance revision variable, by the processor, to obtain an adjusted backlight value of a backlight zone corresponding to the zone image data block.

4. The method according to claim 1 , wherein calculating, by the processor, an adjusted backlight value of a backlight zone corresponding to the zone image data block, based on the zone backlight value, a backlight value gain variable and an ambient luminance revision variable comprises:

multiplying the zone backlight value by a product of a backlight value gain variable and an ambient luminance revision variable, by the processor, to obtain an adjusted backlight value of a backlight zone corresponding to the zone image data block.

5. 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.

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

7. The method according to claim 1 , wherein the ambient luminance revision variable is determined by presetting, by the processor, 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.

8. The method according to claim 1 , wherein driving the backlight source, by the driver circuit, according to the adjusted backlight value to control brightness of the backlight source in the backlight zone comprise:

determining, by a backlight processor in the driver circuit, a duty ratio of a PWM signal according to the adjusted backlight value, and to outputting the duty ratio to a PWM driver in the driver circuit;

generating, by the PWM driver, a PWM control signal according to the duty ratio to control a backlight source in the backlight zone.

9. A liquid crystal display device comprising:

a driver circuit of a backlight source;

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, by the processor, a backlight gain coefficient according to a backlight value gain variable and an ambient luminance revision variable;

multiplying, by the processor, the zone backlight value with the backlight gain coefficient to obtain an adjusted backlight value 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;

outputting the adjusted backlight value of the backlight zone to a driver circuit of a backlight source in the backlight zone; and

the driver circuit of the of a backlight source is configured to drive the backlight source according to the adjusted backlight value to control brightness of the backlight source in the backlight zone.

10. The liquid crystal display device according to claim 9 , wherein the at least one processor executes the at least one instruction to determine a backlight gain coefficient according to a backlight value gain variable and an ambient luminance revision variable by:

searching a preset two-dimension variable lookup table between a backlight value gain variable and a ambient luminance revision variable for the backlight gain coefficient using determined backlight value gain variable and determined ambient luminance revision variable.

11. The liquid crystal display device according to claim 9 , wherein the at least one processor executes the at least one instruction to calculate an adjusted backlight value of a backlight zone corresponding to the zone image data block, based on the zone backlight value, a backlight value gain variable and an ambient luminance revision variable by:

multiplying the zone backlight value by a summation of a backlight value gain variable and an ambient luminance revision variable, by the processor, to obtain an adjusted backlight value of a backlight zone corresponding to the zone image data block.

12. The liquid crystal display device according to claim 9 , wherein the at least one processor executes the at least one instruction to calculate an adjusted backlight value of a backlight zone corresponding to the zone image data block, based on the zone backlight value, a backlight value gain variable and an ambient luminance revision variable by:

multiplying the zone backlight value by a product of a backlight value gain variable and an ambient luminance revision variable, by the processor, to obtain an adjusted backlight value of a backlight zone corresponding to the zone image data block.

13. The liquid crystal display device according to claim 9 , 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.

14. The liquid crystal display device according to claim 9 , wherein the operations further comprise dividing different ambient luminance values into several intervals, each of the intervals corresponding to a value of the ambient luminance revision variable.

15. The liquid crystal display device according to claim 9 , 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.

16. The liquid crystal display device according to claim 9 , wherein the driver circuit comprises a backlight processor and a PWM driver:

the backlight processor is configured to determine a duty ratio of a PWM signal according to the adjusted backlight value, and output the duty ratio to the PWM driver;

the PWM driver is configured to generate a PWM control signal according to the duty ratio to control a backlight source in the backlight zone.