Method of color image display for a field sequential liquid crystal display device

1. A field sequential liquid crystal display device, comprising:

a liquid crystal panel having an upper substrate, a lower substrate and a liquid crystal layer therebetween;

a back light under the liquid crystal panel for irradiating light to the liquid crystal panel and having different light sources for each of the colors Red, Green and Blue; and

a means for controlling a lighting speed of each of light sources Red, Green and Blue, where the light sources are sequentially driven wherein the means indicates a stressed color corresponding to one of the light sources and the means turns on the light sources according to an average luminance value obtained with a luminance value of color components R, G, and B.

2. The device according to claim 1 , wherein the liquid crystal layer mode is Optical Compensated Birefringent (OCB) mode.

3. The device according to claim 1 , wherein the liquid crystal layer mode is Ferroelectric Liquid Crystal (FLC) mode.

4. The device according to claim 1 , wherein each of the light sources is disposed at a down edge of the liquid crystal panel.

5. The device according to claim 1 , wherein each of the light sources is disposed directly under of the liquid crystal panel in a repeated sequence of Red, Green and Blue.

6. The device according to claim 1 , wherein the back light further includes a fourth light source.

7. The device according to claim 6 , wherein a color of the fourth light source is within a color range from Green to Blue.

8. A method of color image display for a field sequential liquid crystal display device including an image signal processor, comprising:

dividing a frame into four sub-frames, each sub-frame having a period of one-fourth of one frame period;

driving each of light sources Red, Green and Blue sequentially at a first, a second and a third sub-frame;

driving a combination of the light sources, the combination having up to three colors at a fourth sub-frame;

classifying a color image input signal into color components R, G and B using a gray level having 256 levels;

deciding a maximum luminance value of the field sequential liquid crystal display device using the gray level; and

obtaining an average luminance value of each of the components R, G and B from the color image input signal.

9. The method according to claim 8 , wherein the combination of light sources turned on at the fourth sub-frame is one of combinations consisting of all off, R, G, B, G+B, R+B, R+G, and all on.

10. The method according to claim 8 , wherein one frame period is 1/60 second.

11. The method according to claim 10 , wherein a lighting time of the light source at each sub-frame is shorter than 1/240 second.

12. A method of color image display for a field sequential liquid crystal display device including an image signal processor, comprising:

dividing a frame having a frame period into four sub-frames having a period of one-fourth of one frame period;

driving each of light sources Red, Green and Blue sequentially at a first, a second and a third sub-frame, respectively;

driving a light source combination with a combination of colors Red, Green and Blue at a fourth sub-frame;

classifying a color image input signal into color components R, G and B using a gray level having 256 levels;

deciding a maximum luminance value of the field sequential liquid crystal display device using the gray level;

obtaining an average luminance value of each of the components R, G and B from the color image input signal; and

turning on light sources Red, Green and Blue corresponding to the one of the color components R, G and B having an average luminance value greater than the maximum luminance value at the fourth sub-frame.

13. The method of claim 12 further comprising: converting the input luminance value of component R, G and B and an input luminance value of the fourth sub-frame using the image signal processor.

14. The method according to claim 13 , wherein a lighting time of the light source at each sub-frame is less than 1/240 second.

15. The method according to claim 12 , wherein the light source which is to be turned on at the fourth sub-frame is decided on the basis of a maximum luminance value of R, G and B.

16. The method according to claim 12 , wherein the frame period is 1/60 second.

17. The method according to claim 12 , wherein a combination of light sources and R, G, and B turned on at the fourth sub-frame is one of combinations consisting of all off, R, G, B, G+B, R+B, R+G, and all on.

18. A method of color image display for a field sequential liquid crystal display device including an image signal processor, comprising:

dividing a frame into four sub-frames, each sub-frame having a period of one-fourth of one frame period;

driving each of light sources Red, Green and Blue sequentially at a first, a second and a third sub-frame, and

driving a fourth light source having a combination of the light sources at a fourth sub-frame

classifying a color image input signal into color components R, G and B using a gray level having 256 levels;

deciding a maximum luminance value of the field sequential liquid crystal display device using the gray level; and

obtaining an average luminance value of each of the components R, G and B from the color image input signal.

19. The method according to claim 18 , wherein the combination of light sources turned on at the fourth sub-frame is one of combinations consisting of all off, R, G, B, G+B, R+B, R+G, and all on.

20. The method according to claim 18 , wherein one frame period is 1/60 second.

21. The method according to claim 20 , wherein a lighting time of the light source at each sub-frame is shorter than 1/240 second.