Method for controlling luminance of backlight unit

• US 20060007104A1
• Filed: 05/27/2005
• Published: 01/12/2006
• Est. Priority Date: 05/28/2004
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Hong, Hee Jung
• Granted Patent: US 8,085,237 B2
• Time in Patent Office: Days
• US Class Current: 345/102
• CPC Class Codes: G09G 2320/0285 using tables for spatial correction of display data
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/066 for control of contrast
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/2014 by modulation of the duration of a single pulse during which the logic level remains constant
• 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

Abstract

A method for controlling luminance of an edge type backlight unit having a plurality of lamps at opposite sides of a light-guiding plate is provided that includes: analyzing luminance data for each frame of an image before outputting the image; selecting a backlight luminance level from a Look-Up Table LUT that classifies the luminance according to the analyzed luminance data; outputting lamp on/off control signals according to the selected luminance level; and providing lamp on/off signals to respective lamps according to the lamp on/off control signals.

Claims

1. A method for controlling luminance of an edge type backlight unit having a plurality of lamps at opposite sides of a light-guiding plate, the method comprising:

analyzing luminance data for each frame of an image before outputting the image;

selecting a luminance level from a Look-Up Table LUT that classifies luminance according to the analyzed luminance data;

outputting lamp on/off control signals according to the selected luminance level; and

providing lamp on/off signals to respective lamps according to the lamp on/off control signals.

2. The method of claim 1, wherein the luminance data is divided into a plurality of luminance levels.

3. The method of claim 2, wherein the luminance data is divided into three luminance levels including a minimum, intermediate and maximum luminance level.

4. The method of claim 3, wherein the luminance data is equally divided into the three luminance levels.

5. The method of claim 2, wherein the Look-Up Table includes preset lamp on/off control signals that provide the number of lamps being turned-on for each luminance level.

6. A method for controlling luminance of an edge type backlight unit having a plurality of lamps at opposite sides of a light-guiding plate, the method comprising:

analyzing luminance data for each frame of an image before outputting the image;

selecting a luminance level from a Look-Up Table that classifies the luminance according to the analyzed luminance data;

outputting lamp on/off control signals and lamp-dimming control signals according to the selected luminance level; and

providing lamp on/off signals to respective lamps according to the lamp on/off control signals and the lamp-dimming control signals.

7. The method of claim 6, wherein the luminance data is divided into a plurality of luminance levels.

8. The method of claim 7, wherein the luminance data is divided into three luminance levels including a minimum, intermediate and maximum luminance level.

9. The method of claim 8, wherein the luminance data is equally divided into the three luminance levels.

10. The method of claim 6, wherein the lamp-dimming control signal applied in a pulse width modulation PWM method or an analog variable resistance control method.

11. The method of claim 10, wherein the lamp-dimming control signal is applied using a burst inverter, or using an analog inverter.

12. The method of claim 6, wherein the Look-Up Table includes preset lamp on/off control signals that provide the number of lamps being turned-on for each luminance level.