METHOD AND APPARATUSFOR CONTROLLING LIQUID CRYSTAL DISPLAY BRIGHTNESS AND LIQUID CRYSTAL DISPLAY DEVICE

• US 20180090082A1
• Filed: 02/10/2017
• Published: 03/29/2018
• Est. Priority Date: 09/28/2016
• 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
• Granted Patent: US 10,176,770 B2
• Time in Patent Office: Days
• CPC Class Codes: G09G 2310/0237 Switching ON and OFF the backlight within one frame
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 3/3607 for displaying colours or for displaying grey scales with a specific pixel layout, e.g. using sub-pixels display of colours in flat matrix panels other than liquid crystal displays G09G3/2003; grey scales specific for television H04N3/127

Abstract

Embodiments of the present application provide a method and apparatus for controlling liquid crystal display brightness, and a liquid crystal display device. The method for controlling liquid crystal display brightness according to the present application determines a backlight adjustment rule according to a grayscale value distribution of an image signal and a first preset rule, adjusts a zoned backlight value corresponding to a zoned image data block according to the backlight adjustment rule, as well as drives and controls the backlight source brightness of the corresponding backlight zone by using the adjusted zoned backlight value, thereby adjusting the zoned backlight values for image signals of different grayscale value distributions by using different backlight adjustment rules, significantly improving the picture hierarchy of different image signals, and enhancing the displaying quality of the picture.

Claims

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

determining a backlight adjustment rule according to a grayscale value distribution of an image signal and a first preset rule;

determining a zoned image data block according to the image signal and a preset division rule, and determining a zoned backlight value corresponding to the zoned image data block according to a grayscale value of the zoned image data block;

adjusting the zoned backlight value according to the backlight adjustment rule to obtain an adjusted zoned backlight value; and

mapping the adjusted zoned backlight value to a drive circuit of a backlight source of a corresponding backlight zone, so as to drive and control backlight source brightness of the corresponding backlight zone;

wherein the grayscale value distribution of the image signal represents a grayscale value distribution of pixels of the image signal, the first preset rule comprises a corresponding relationship between the grayscale value distribution and the backlight adjustment rule, and the backlight adjustment rule is the corresponding relationship between a backlight value and an adjustment coefficient.

2. The method according to claim 1, further comprising:

generating a grayscale histogram according to the grayscale value of the pixels of the image signal; and

determining the grayscale value distribution of the image signal according to the grayscale histogram.

3. The method according to claim 2, wherein the generating the grayscale histogram according to the grayscale value of the pixels of the image signal comprises:

generating the grayscale histogram of the zoned image data block according to the grayscale value of pixels of the zoned image data block;

the determining the grayscale value distribution of the image signal according to the grayscale histogram of the image signal comprises;

determining the grayscale value distribution of the zoned image data block according to the grayscale histogram of the zoned image data block.

4. The method according to claim 1, wherein the determining the backlight adjustment rule according to the grayscale value distribution of the image signal and the first preset rule comprises:

if the grayscale value distribution of the zoned image data block is a distribution with more more low grayscale values than high grayscale values, then an adjustment coefficient corresponding to the backlight value of low brightness is greater than 1, and an adjustment coefficient corresponding to the backlight value of high brightness is smaller than 1; and

if the grayscale value distribution of the zoned image data block is a distribution with less low grayscale values than high grayscale values, then the adjustment coefficient corresponding to the backlight value of high brightness is greater than 1, and the adjustment coefficient corresponding to the backlight value of low brightness is smaller than 1.

5. The method according to claim 2, wherein the determining the backlight adjustment rule according to the grayscale value distribution of the image signal and the first preset rule comprises:

generating a peripheral envelope curve of the grayscale histogram according to the grayscale histogram;

determining the backlight adjustment rule according to the peripheral envelope curve and the first preset rule.

6. The method according to claim 5, wherein the determining the backlight adjustment rule according to the peripheral envelope curve and the first preset rule comprises:

if the peripheral envelope curve is a forwarded S-shaped curve, then the adjustment coefficient corresponding to the backlight value of the high brightness is greater than 1, and the adjustment coefficient corresponding to the backlight value of the low brightness is smaller than 1;

if the peripheral envelope curve is an reversed S-shaped curve, then the adjustment coefficient corresponding to the backlight value of the low brightness is greater than 1, and the adjustment coefficient corresponding to the backlight value of the high brightness is smaller than 1; and

if the peripheral envelope curve is a horizontal straight line, the adjustment coefficient corresponding to each backlight value is 1.

7. An apparatus for controlling liquid crystal display brightness, comprising:

a memory for storing instructions; and

a processor coupled to the memory, the processor is configured to execute the instructions stored in the memory, and the processor is configured to;

determine a backlight adjustment rule according to a grayscale value distribution of an image signal and a first preset rule;

determine a zoned image data block according to the image signal and a preset division rule, and determine a zoned backlight value corresponding to the zoned image data block according to a grayscale value of the zoned image data block;

adjust the zoned backlight value according to the backlight adjustment rule to obtain an adjusted zoned backlight value; and

map the adjusted zoned backlight value to a drive circuit of a backlight source of a corresponding backlight zone, so as to drive and control backlight source brightness of the corresponding backlight zone;

wherein the grayscale value distribution of the image signal represents a grayscale value distribution of pixels of the image signal, the first preset rule comprises a corresponding relationship between the grayscale value distribution and the backlight adjustment rule, and the backlight adjustment rule is the corresponding relationship between a backlight value and an adjustment coefficient.

8. The apparatus according to claim 7, wherein the processor is further configured to:

generate a grayscale histogram according to the grayscale value of the pixels of the image signal; and

determine the grayscale value distribution of the image signal according to the grayscale histogram.

9. The apparatus according to claim 8, wherein the processor is configured to:

generate the grayscale histogram of the zoned image data block according to the grayscale value of pixels of the zoned image data block; and

determine the grayscale value distribution of the zoned image data block according to the grayscale histogram of the zoned image data block.

10. The apparatus according to claim 7, wherein the processor is configured to:

if the grayscale value distribution of the zoned image data block is a distribution with more low grayscale values than high grayscale values, then an adjustment coefficient corresponding to the backlight value of low brightness is greater than 1, and an adjustment coefficient corresponding to the backlight value of high brightness is less than 1; and

if the grayscale value distribution of the zoned image data block is a distribution with less low grayscale values than high grayscale values, then the adjustment coefficient corresponding to the backlight value of high brightness is greater than 1, and the adjustment coefficient corresponding to the backlight value of low brightness is smaller than 1.

11. The apparatus according to claim 8, wherein the processor is configured to:

generate a peripheral envelope curve of the grayscale histogram according to the grayscale histogram; and

determine the backlight adjustment rule according to the peripheral envelope curve and the first preset rule.

12. The apparatus according to claim 11, wherein the processor is configured to:

if the peripheral envelope curve is a forwarded S-shaped curve, then the adjustment coefficient corresponding to the backlight value of the high brightness is greater than 1, and the adjustment coefficient corresponding to the backlight value of the low brightness is smaller than 1;

if the peripheral envelope curve is an reversed S-shaped curve, then the adjustment coefficient corresponding to the backlight value of the low brightness is greater than 1, and the adjustment coefficient corresponding to the backlight value of the high brightness is smaller than 1; and

if the peripheral envelope curve is a horizontal straight line, the adjustment coefficient corresponding to each backlight value is 1.

13. A liquid crystal display device, comprising:

a memory, a processor, a backlight processor, and a pulse width modulation (PWM) driver, wherein the memory, the processor, the backlight processor, and the PWM driver are connected via a bus; and

wherein;

the memory is configured to store instructions;

the processor is configured to execute the instructions stored in the memory, and the processor is also configured to receive an image signal for data processing, output processed image data to a timing controller which generates a driving signal for controlling image displaying of a liquid crystal panel according to the processed image data, and output a zoned backlight value to a backlight processor according to the processed image signal;

the processor is further configured to;

determine a backlight adjustment rule according to a grayscale value distribution of the image signal and a first preset rule;

determine a zoned image data block according to the image signal and a preset division rule, and determine a zoned backlight value corresponding to the zoned image data block according to a grayscale value of the zoned image data block;

adjust the zoned backlight value according to the backlight adjustment rule, to obtain an adjusted zoned backlight value; and

map the adjusted zoned backlight value to a drive circuit of a backlight source of a corresponding backlight zone, so as to drive and control backlight source brightness of the corresponding backlight zone;

wherein the grayscale value distribution of the image signal represents a grayscale value distribution of pixels of the image signal, the first preset rule comprises a corresponding relationship between the grayscale value distribution and the backlight adjustment rule, and the backlight adjustment rule is the corresponding relationship between a backlight value and an adjustment coefficient;

the backlight processor is configured to determine, according to each zoned backlight value, a duty cycle and current data of a corresponding PWM signal, and output the duty cycle and the current data of the corresponding PWM signal to the PWM driver; and

the PWM driver is configured to generate a PWM control signal to control a backlight source of a corresponding backlight zone.

14. The device according to claim 13, wherein the memory is further configured to store various types of data of preset lookup table;

and

the processor is further configured to execute the instructions in the memory for calling the various types of the data of the preset lookup table.