Video display driving method of LCD

Abstract

A video display driving method of a liquid crystal display (LCD) receives a plurality of sets of video frame data for an LCD panel. The method transforms each set of the video frame data into a preset-voltage signal and a post-set-voltage signal for driving a plurality of pixels during a frame time. A light source brightness of a backlight module presents a first average brightness during a corresponding time when the preset-voltage signal is written into the pixel, and presents a second average brightness during a corresponding time when the post-set-voltage signal is written into the pixel. The second average brightness is greater than the first average brightness. In addition, when a dynamic brightness control is performed during at least one frame time, the driving method adjusts the second average brightness according to a result of the dynamic brightness control.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will become more fully understood from the detailed description given herein below illustration only, and thus is not limitative of the present invention, and wherein:

FIG. 1 is a schematic illustration showing a cross-sectional side view of a conventional LCD;

FIG. 2A is a schematic illustration showing a driving voltage variation of a pixel in a video display driving method of the conventional LCD;

FIG. 2B is a schematic illustration showing a transmittance variation of a pixel on a display surface when the voltage of FIG. 2A is used to drive the pixel, wherein the solid line represents the liquid crystal of the pixel with longer response time and the dashed line represents the liquid crystal of the pixel with shorter response time;

FIG. 2C is a schematic illustration showing an intensity variation of a light source at a position of the pixel in the conventional backlight module;

FIG. 2D is a schematic illustration showing a brightness variation presented by the pixel on the display surface;

FIG. 3A is a schematic illustration showing a driving voltage variation of a pixel according to a video display driving method of a LCD according to a preferred embodiment of the invention;

FIG. 3B is a schematic illustration showing a transmittance variation of the pixel on a display surface when the voltage of FIG. 3A is used to drive the pixel;

FIG. 3C is a schematic illustration showing an intensity variation of a light source at a position of the pixel in the backlight module; and

FIG. 3D is a schematic illustration showing a brightness variation presented by the pixel on the display surface.

Claims

1. A video display driving method of a liquid crystal display (LCD), the LCD comprising a liquid crystal display panel and a backlight module, wherein the liquid crystal display panel has a plurality of pixels distributed over a display surface of the liquid crystal display panel, a light source of the backlight module is projected onto the display surface of the liquid crystal display panel, the liquid crystal display panel receives a plurality of sets of video frame data and transforms each of the sets of video frame data into a preset-voltage signal and a post-set-voltage signal for driving the pixels during a frame time, a light source brightness of the backlight module presents a first average brightness while the preset-voltage signal is written into at least one of the pixels and presents a second average brightness while the post-set-voltage signal is written into the pixel, and the second average brightness is greater than the first average brightness, the method comprising a step of: performing a dynamic brightness control during the frame time; andadjusting the second average brightness according to a result of the dynamic brightness control.

2. The method according to claim 1, wherein the post-set-voltage signal is adjusted according to the result of the dynamic brightness control during the frame time.

3. The method according to claim 1, wherein the preset-voltage signal pertaining to each of the sets of video frame data is a set of exaggerated voltage signals corresponding to the post-set-voltage signal pertaining to the video frame data.

4. The method according to claim 1, wherein the dynamic brightness control increases a transmittance of the pixel according to a ratio during the frame time, and decreases the second average brightness according to the ratio.

5. The method according to claim 4, wherein the transmittance of the pixel is controlled by the post-set-voltage signal.

6. The method according to claim 4, wherein the ratio is a ratio of the transmittance of the pixel to a maximum transmittance of the pixel.

7. The method according to claim 1, wherein the backlight module comprises a plurality of light emitting elements.

8. The method according to claim 7, wherein a brightness of at least one of the light emitting elements of the backlight module is decreased within the corresponding time when the preset-voltage signal is written into the pixel, and a brightness of the at least one of the light emitting elements of the backlight module is increased within the corresponding time when the post-set-voltage signal is written into the pixel.

9. The method according to claim 8, wherein the light emitting element whose brightness is increased is closest to the pixel.

10. The method according to claim 8, wherein the light emitting element whose brightness is decreased is closest to the pixel.

11. The method according to claim 7, wherein the light emitting elements of the backlight module are light-emitting diodes.

12. The method according to claim 7, wherein the light emitting elements of the backlight module are cold cathode fluorescent lamps (CCFLs).

13. The method according to claim 7, wherein the light emitting elements of the backlight module are plane lamps.

14. The method according to claim 1, wherein a time interval from a time period, in which the preset-voltage signal drives the pixel, to another time period, in which the post-set-voltage signal drives the pixel is substantially equal to one half of the frame time.

15. The method according to claim 1, wherein 1/50 seconds≧frame time≧ 1/120 seconds.

16. The method according to claim 1, wherein the backlight module is a bottom lighting backlight module.

17. The method according to claim 1, wherein the backlight module is an edge lighting backlight module.

18. The method according to claim 1, wherein the LCD is an LCD TV.