Apparatus and method for driving liquid crystal display device

• US 20050140622A1
• Filed: 10/15/2004
• Published: 06/30/2005
• Est. Priority Date: 12/30/2003
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Inventors: Lee, Han Sang, Lee, Myung Ho
• Granted Patent: US 7,133,049 B2
• Time in Patent Office: Days
• US Class Current: 345/88
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3607 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

A display device includes a display panel having a plurality of pixels, each pixel including R, Q B and W sub-pixels; a color information detecting unit receiving R, G and B sub-pixel video data for each pixel and outputting a detecting signal when one or two of the R, G and B sub-pixel video data are null; a color component determining unit receiving the detecting signals for the entire pixels, operating the detecting signals, comparing the operated detecting signals with at least one reference value, and outputting a control singal; and a light source control unit controlling an amount of a light source according to the control signal.

Claims

1. A display device comprising:

a display panel having a plurality of pixels, each pixel including R, G, B and W sub-pixels;

a color information detecting unit receiving R, G and B sub-pixel video data for each pixel and outputting first and second signals, wherein the first signal is different from the second signal, and the color information detecting unit outputs the first signal when one or two of the R, G and B sub-pixel video data are null;

a color component determining unit counting the number of the first signal, comparing the number of the first signal with at least one reference value, and outputting a control singal; and

a light source control unit controlling an amount of light according to the control signal.

2. The device according to claim 1, wherein the display device is a liquid crystal display device.

3. The device according to claim 1, wherein the reference value is stored in a look-up table(LUT).

4. The device according to claim 1, wherein the color information detecting unit includes an Exclusive-OR logic gate.

5. The device according to claim 4, wherein the Exclusive-OR logic gate includes a NOR gate, an OR gate and an AND gate.

6. The device according to of claim 1, wherein the color information detecting unit comprises:

a red detecting unit for detecting whether the red sub-pixel video data has a value or null;

a green detecting unit for detecting whether the green sub-pixel video data has a value or null;

a blue detecting unit for detecting whether the blue sub-pixel video data has a value or null;

a first OR gate for reversing and receiving signals outputted from the red, green and blue detecting units and for performing OR-function;

a second OR gate for receiving signals outputted from the red, green and blue detecting units and for performing OR-function; and

a first AND gate for receiving the signals outputted from the first and second OR gates, performing AND-function, and outputting the first or second signals to the color component determining unit.

7. The device according to claim 1, wherein the color component determining unit comprises:

an operating unit for receiving the first or second signals from the color information detecting unit and counting the number of the first signals for an entire image; and

a comparing unit for comparing the number of the first signals with at least one reference value, and outputting a control singal to the light source control unit.

8. The device according to claim 1, wherein the light source control unit carries out pulse operated by pulse width modulation (PWM) and controls an amount of light.

9. A display device comprising:

a display panel having a plurality of pixels, each pixel including R, G, B and W sub-pixels;

a color information detecting unit receiving R, G and B sub-pixel video data for each pixel and outputting a detecting signal when one or two of the R, G and B sub-pixel video data are null;

a color component determining unit receiving the detecting signals for the entire pixels, operating the detecting signals, comparing the operated detecting signals with at least one reference value, and outputting a control singal; and

a light source control unit controlling an amount of light according to the control signal.

10. The device according to claim 9, wherein the reference value is stored in a look-up table(LUT).

11. The device according to claim 9, wherein the color information detecting unit includes an Exclusive-OR logic gate.

12. The device according to claim 11, wherein the Exclusive-OR logic gate includes a NOR gate, an OR gate and an AND gate.

13. The device according to claim 9, wherein the display device is a liquid crystal display device.

14. The device according to claim 9, wherein the light source includes an LED (Light Emitting Diode).

15. A method for driving a display device having a plurality of pixels, each pixel including R, G, B and W sub-pixels, the method comprising:

receiving R, G and B sub-pixel video data for each pixel and outputting a detecting signal when one or two of the R, G and B sub-pixel video data are null;

receiving the detecting signals for the entire pixels, operating the detecting signals, comparing the operated detecting signals with at least one reference value, and outputting a control singal; and

controlling an amount of light according to the control signal.

16. The method according to claim 15, wherein the reference value is stored in a look-up table(LUT).

17. The method according to claim 15, wherein the display device is a liquid crystal display device.

18. The method according to claim 15, wherein the light source includes an LED (Light Emitting Diode).

19. The method according to claim 15, wherein the operating the detecting signals is counting the number of the detecting signals.