Apparatus and method for controlling backlight and liquid crystal display

• US 20080129680A1
• Filed: 11/20/2007
• Published: 06/05/2008
• Est. Priority Date: 12/01/2006
• Status: Active Grant

• Current Assignee: Saturn Licensing LLC (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Kimura, Kazuto, Asano, Mitsuyasu, Hayashi, Masatake, Katsu, Yoshihiro, Aoki, Tomio
• Granted Patent: US 8,400,392 B2
• Time in Patent Office: Days
• US Class Current: 345/102
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/028 by changing the viewing angle properties, e.g. widening the viewing angle, adapting the viewing angle to the view direction
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix

Abstract

Disclosed is a backlight control apparatus for controlling a backlight used in a liquid crystal display, the backlight having a lighting area that includes a plurality of blocks in each of which a backlight luminance is individually allowed to change. The apparatus includes a backlight control unit that calculates the backlight luminance of each block so that the absolute value of the difference between a backlight lighting ratio and 1 is at or below a first value, and controls the backlight so as to yield the calculated backlight luminances of the respective blocks, the backlight lighting ratio being the ratio between backlight set values of neighboring blocks.

Claims

1. A backlight control apparatus for controlling a backlight used in a liquid crystal display, the backlight having a lighting area that includes a plurality of blocks in each of which a backlight luminance is individually allowed to change, the apparatus comprising:

backlight control means that calculates the backlight luminance of each block so that the absolute value of the difference between a backlight lighting ratio and 1 is at or below a first value, and controls the backlight so as to yield the calculated backlight luminances of the respective blocks, the backlight lighting ratio being the ratio between backlight set values of neighboring blocks.

2. The apparatus according to claim 1, wherein the backlight lighting ratio is calculated on the condition that the absolute value of the difference between 1 and the ratio between the backlight luminances of pixels away from each other by a predetermined distance in the lighting area is at or below a second value.

3. A method of controlling a backlight used in a liquid crystal display, the backlight having a lighting area that includes a plurality of blocks in each of which a backlight luminance is individually allowed to change, the method comprising the steps of:

calculating the backlight luminance of each block so that the absolute value of the difference between a backlight lighting ratio and 1 is at or below a first value, the backlight lighting ratio being the ratio between backlight set values of neighboring blocks; and

controlling the backlight so as to yield the calculated backlight luminances of the respective blocks.

4. The method according to claim 3, wherein the backlight lighting ratio is calculated on the condition that the absolute value of the difference between 1 and the ratio between the backlight luminances of pixels away from each other by a predetermined distance in the lighting area is at or below a second value.

5. A liquid crystal display comprising:

a backlight that has a lighting area including a plurality of blocks in each of which a backlight luminance is individually allowed to change; and

backlight control means that calculates the backlight luminance of each block so that the absolute value of the difference between a backlight lighting ratio and 1 is at or below a first value, and controls the backlight so as to yield the calculated backlight luminances of the respective blocks, the backlight lighting ratio being the ratio between backlight set values of neighboring blocks.

6. The liquid crystal display according to claim 5, wherein the backlight lighting ratio is calculated on the condition that the absolute value of the difference between 1 and the ratio between the backlight luminances of pixels away from each other by a predetermined distance in the lighting area is at or below a second value.

7. A backlight control apparatus for controlling a backlight used in a liquid crystal display, the backlight having a lighting area that includes a plurality of blocks in each of which a backlight luminance is individually allowed to change, the apparatus comprising:

a backlight control unit that calculates the backlight luminance of each block so that the absolute value of the difference between a backlight lighting ratio and 1 is at or below a first value, and controls the backlight so as to yield the calculated backlight luminances of the respective blocks, the backlight lighting ratio being the ratio between backlight set values of neighboring blocks.

8. A liquid crystal display comprising:

a backlight that has a lighting area including a plurality of blocks in each of which a backlight luminance is individually allowed to change; and

a backlight control unit that calculates the backlight luminance of each block so that the absolute value of the difference between a backlight lighting ratio and 1 is at or below a first value, and controls the backlight so as to yield the calculated backlight luminances of the respective blocks, the backlight lighting ratio being the ratio between backlight set values of neighboring blocks.