Backlight unit of liquid crystal display device and method for driving the same

• US 20060007112A1
• Filed: 06/28/2005
• Published: 01/12/2006
• Est. Priority Date: 06/29/2004
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Inventors: Park, Hee Jeong
• Granted Patent: US 8,721,096 B2
• Time in Patent Office: Days
• US Class Current: 345/102
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

A backlight unit of an LCD device includes a first light source unit including a plurality of red, green and blue LEDs and a second light source unit including a plurality of white LEDs, the white LED provided between each of the first light source unit. A control unit divides the plurality of first and second light source units into a plurality of blocks and outputs control signals to the first and second light source units by detecting the luminance of inputted video signals. The backlight unit includes a first light source driving unit for driving the first light source and a second light source driving unit for driving the second light source by corresponding block to the first light source unit.

Claims

1. A backlight unit of an LCD device comprising:

a first light source unit including a plurality of red, green and blue LEDs;

a second light source unit including a plurality of white LEDs, the white LEDs provided between each of the plurality of red, green and blue LEDs;

a control unit that divides the plurality of red, green, blue and white LEDs into a plurality of blocks, and outputs control signals to the first light source unit and the second light source unit by detecting the luminance of inputted video signals;

a first light source driving unit that drives the first light source unit according to the control signal of the first light source unit; and

a second light source driving unit that drives the second light source unit by each block according to the control signal of the second light source unit.

2. The backlight unit of claim 1, wherein the second light source driving unit drives the second light source unit of a corresponding block when the controller analyzes the luminance of the inputted video signal by each block, and the analyzed luminance is below the predetermined reference value.

3. The backlight unit of claim 1, wherein the first light source unit and the second light source unit have the LEDs arranged in order of red, green, blue and white on a PCB substrate.

4. A method for driving a backlight unit of an LCD device, the backlight unit including a plurality of red, green, blue and white LEDs, the plurality of red, green, blue and white LEDs being divided into a plurality of blocks, comprising:

analyzing a luminance of an inputted video signal by each block; and

turning on the white LEDs of a corresponding block when the analyzed luminance of the corresponding block is below a predetermined reference value.

5. A backlight unit of an LCD device comprising:

a first light source unit having a plurality of red, green and blue LEDs;

a second light source unit having a plurality of white LEDs, wherein the plurality of red, green, blue, and white LEDs being divided into a plurality of blocks;

a control unit that outputs a first control signal to the first light source unit and a second control signal to the second light source unit based upon the luminance for the inputted video signal;

a first light source driving unit that drives the first light source according to the first control signal; and

a second light source driving unit that drives the second light source in a corresponding block of the second light source according to the second control signal.

6. The backlight unit of claim 5, wherein the second light source driving unit drives the second light source unit of the corresponding block when the controller analyzes the luminance of the inputted video signal by each block, and the analyzed luminance is below the predetermined reference value.

7. The backlight unit of claim 5, wherein the combination of the first light source unit and the second light source unit have the LEDs arranged in order of red, green, blue and white on a PCB substrate.