Method and device for adjusting grayscale brightness and 3D display device

• US 9,704,427 B2
• Filed: 05/28/2015
• Issued: 07/11/2017
• Est. Priority Date: 12/10/2014
• Status: Active Grant

• Current Assignee: Maxell, 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: Huang, Shunming, Zhang, Yuxin, Yang, Jia, Yang, Jie
• Primary Examiner(s): Dicke, Chad
• Application Number:
  US14/723,633
• Publication Number:
  US 20160173862A1
• Time in Patent Office: 775 Days
• Field of Search: 345102
• CPC Class Codes: G09G 2320/0252 Improving the response speed
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 3/003 to produce spatial visual effects
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 3/2007 Display of intermediate tones
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/342 using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
• CPC Class Codes: H04N 13/398 Synchronisation thereof; Control thereof

Abstract

The disclosure discloses a method and device for adjusting grayscale brightness and a 3D display device. In the present disclosure, an initial gray level and a target gray level are determined, and it is determined whether the target gray level is too low or too high, so that it is determined whether over-voltage driving can be applicable, and in the case that it is not appropriate to adjust grayscale brightness through over-voltage driving, a backlight brightness adjustment table is searched, and backlight brightness is adjusted up or down using a found adjustment parameter to thereby adjust the grayscale brightness so as to reduce crosstalk in liquid crystal display.

Claims

1. A method for adjusting grayscale brightness, applicable to a 3D display device, the method comprising:

determining an initial gray level corresponding to a preceding frame, and a target gray level corresponding to a current frame, for a backlight zone corresponding to a zone of a display image;

determining whether the target gray level is less than a first threshold gray level or greater than a second threshold gray level, wherein the first threshold gray level is less than the second threshold gray level; and

if not, then in response to determining the target gray level is not less than the first threshold gray level and not greater than the second threshold gray level, adjusting the grayscale brightness of the backlight zone through over-voltage driving,

in response to determining the target gray level is less than the first threshold gray level or greater than the second threshold gray level, determining a value of an adjustment parameter corresponding to the initial gray level and the target gray level according to a preset backlight brightness adjustment table, and adjusting backlight brightness of the current frame according to the determined value of the adjustment parameter so that grayscale brightness of the current frame substantially equals grayscale brightness corresponding to the target gray level,

wherein the adjustment parameter is a duty cycle of backlight or a reference current of backlight.

2. The method according to claim 1, wherein determining the value of the adjustment parameter corresponding to the initial gray level and the target gray level according to the preset backlight brightness adjustment table comprises:

searching the preset backlight brightness adjustment table for the value of the adjustment parameter corresponding to the initial gray level and the target gray level when the initial gray level and the target gray level are present in the backlight brightness adjustment table; and

calculating the value of the adjustment parameter corresponding to the initial gray level and the target gray level according to the backlight brightness adjustment table using an interpolation algorithm when the initial gray level and the target gray level are not present in the backlight brightness adjustment table.

3. The method according to claim 2, wherein when the adjustment parameter is the duty cycle of backlight, adjusting the backlight brightness of the current frame according to the determined value of the duty cycle of backlight so that the grayscale brightness of the current frame substantially equals the grayscale brightness corresponding to the target gray level comprises:

if the target gray level is less than the initial gray level, then adjusting down the backlight brightness of the current frame according to the determined value of the duty cycle of backlight so that the grayscale brightness of the current frame substantially equals the grayscale brightness corresponding to the target gray level; and

if the target gray level is more than the initial gray level, then adjusting up the backlight brightness of the current frame according to the determined value of the duty cycle of backlight so that the grayscale brightness of the current frame substantially equals the grayscale brightness corresponding to the target gray level.

4. The method according to claim 2, wherein when the adjustment parameter is the reference current of backlight, adjusting the backlight brightness of the current frame according to the determined value of the reference current of backlight so that the grayscale brightness of the current frame substantially equals the grayscale brightness corresponding to the target gray level comprises:

if the target gray level is less than the initial gray level, then adjusting down the backlight brightness of the current frame according to the determined value of the reference current of backlight so that the grayscale brightness of the current frame substantially equals the grayscale brightness corresponding to the target gray level; and

if the target gray level is more than the initial gray level, then adjusting up the backlight brightness of the current frame according to the determined value of the reference current of backlight so that the grayscale brightness of the current frame substantially equals the grayscale brightness corresponding to the target gray level.

5. The method according to claim 1, wherein the backlight brightness adjustment table is preset as follows:

for the backlight zone, the reference current of backlight for the backlight zone is maintained, and when the initial gray level corresponding to the preceding frame is adjusted to the target gray level corresponding to the current frame, the duty cycle of backlight for the backlight zone is adjusted so that the grayscale brightness of the current frame equals the grayscale brightness corresponding to the target gray level, and a value of the duty cycle of backlight at the grayscale brightness is recorded; and

wherein the initial gray level ranges from 0 to 255, and the target gray level ranges throughout gray levels which are less than the first threshold gray level and gray levels which are greater than the second threshold gray level in the preset set of gray levels.

6. The method according to claim 1, wherein the backlight brightness adjustment table is preset as follows:

for the backlight zone, the duty cycle of backlight for the backlight zone is maintained, and when the initial gray level corresponding to the preceding frame is adjusted to the target gray level corresponding to the current frame, the reference current of backlight for the backlight zone is adjusted so that the grayscale brightness of the current frame equals the grayscale brightness corresponding to the target gray level, and the value of the reference current of backlight at the grayscale brightness is recorded; and

wherein the initial gray level ranges from 0 to 255, and the target gray level ranges throughout gray levels which are less than the first threshold gray level and gray levels which are greater than the second threshold gray level.

7. A 3D display device, comprising a device for adjusting grayscale brightness, wherein the device for adjusting grayscale brightness comprising:

one or more processors; and

a non-transitory memory,

wherein one or more computer readable program codes are stored in the non-transitory memory, and the one or more processors are configured to execute the one or more computer readable program codes to;

determine an initial gray level corresponding to a preceding frame, and a target gray level corresponding to a current frame, for a backlight zone corresponding to a zone of a display image;

determine whether the target gray level is less than a first threshold gray level or greater than a second threshold gray level, wherein the first threshold gray level is less than the second threshold gray level; and

in response to determining the target gray level is not less than the first threshold gray level and not greater than the second threshold gray level, adjust the grayscale brightness of the backlight zone through over-voltage driving,

in response to determining the target gray level is less than the first threshold gray level or greater than the second threshold gray level, determine a value of an adjustment parameter corresponding to the initial gray level and the target gray level according to a preset backlight brightness adjustment table, and adjust backlight brightness of the current frame according to the determined value of the adjustment parameter so that grayscale brightness of the current frame substantially equals grayscale brightness corresponding to the target gray level,

wherein the adjustment parameter is a duty cycle of backlight or a reference current of backlight.

8. The 3D display device according to claim 7, wherein the one or more processors are further configured to execute the one or more computer readable program codes to:

search the backlight brightness adjustment table for the value of the adjustment parameter corresponding to the initial gray level and the target gray level when the initial gray level and the target gray level are present in the backlight brightness adjustment table; and

calculate the value of the adjustment parameter corresponding to the initial gray level and the target gray level according to the backlight brightness adjustment table using an interpolation algorithm when the initial gray level and the target gray level are not present in the backlight brightness adjustment table.

9. The 3D display device according to claim 8, wherein the one or more processors are further configured to execute the one or more computer readable program codes to:

if the target gray level is less than the initial gray level, adjust down the backlight brightness of the current frame according to the determined value of the duty cycle of backlight so that the grayscale brightness of the current frame equals the grayscale brightness corresponding to the target gray level; and

if the target gray level is more than the initial gray level, adjust up the backlight brightness of the current frame according to the determined value of the duty cycle of backlight so that the grayscale brightness of the current frame substantially equals the grayscale brightness corresponding to the target gray level.

10. The 3D display device according to claim 8, wherein the one or more processors are further configured to execute the one or more computer readable program codes to:

if the target gray level is less than the initial gray level, adjust down the backlight brightness of the current frame according to the determined value of the reference current of backlight so that the grayscale brightness of the current frame equals the grayscale brightness corresponding to the target gray level; and

if the target gray level is more than the initial gray level, adjust up the backlight brightness of the current frame according to the determined value of the reference current of backlight so that the grayscale brightness of the current frame substantially equals the grayscale brightness corresponding to the target gray level.

11. The device according to claim 7, wherein the backlight brightness adjustment table is preset as follows:

for the backlight zone, the reference current of backlight for the backlight zone is maintained, and when the initial gray level corresponding to the preceding frame is adjusted to the target gray level corresponding to the current frame, the duty cycle of backlight for the backlight zone is adjusted so that the grayscale brightness of the current frame equals the grayscale brightness corresponding to the target gray level, and a value of the duty cycle of backlight at the grayscale brightness is recorded; and

wherein the initial gray level ranges from 0 to 255, and the target gray level ranges throughout gray levels which are less than the first threshold gray level and gray levels which are greater than the second threshold gray level.

12. The device according to claim 7, wherein the backlight brightness adjustment table is preset as follows:

for the backlight zone, the duty cycle of backlight for the backlight zone is maintained, and when the initial gray level corresponding to the preceding frame is adjusted to the target gray level corresponding to the current frame, the reference current of backlight for the backlight zone is adjusted so that the grayscale brightness of the current frame equals the grayscale brightness corresponding to the target gray level, and the value of the reference current of backlight at the grayscale brightness is recorded; and

wherein the initial gray level ranges from 0 to 255, and the target gray level ranges throughout gray levels which are less than the first threshold gray level and gray levels which are greater than the second threshold gray level.

13. A display device, comprising a device for adjusting grayscale brightness, wherein the device for adjusting grayscale brightness comprising:

one or more processors; and

a non-transitory memory,

wherein one or more computer readable program codes are stored in the non-transitory memory, and the one or more processors are configured to execute the one or more computer readable program codes to;

determine an initial gray level corresponding to a preceding frame, and a target gray level corresponding to a current frame, for a backlight zone corresponding to a zone of a display image;

adjust the grayscale brightness of the backlight zone through over-voltage driving, when the target gray level is not less than a first threshold gray level and not greater than a second threshold gray level; and

determine a value of an adjustment parameter corresponding to the initial gray level and the target gray level according to a preset backlight brightness adjustment table, and adjust backlight brightness of the current frame according to the determined value of the adjustment parameter, when the target gray level is less than the first threshold gray level or greater than the second threshold gray level.