Liquid crystal display device and method for driving the same
View Patent ↗A liquid crystal panel includes a plurality of display regions that correspond to the division images. The number of the division images can be set with consideration of the number of lamps covering the display regions. The average brightness of an entire image is compared with the average brightness of the division images so as to vary brightness of each division image according to a comparison result. Light that corresponds to the varied brightness is illuminated to each display region. Therefore, a dark division image is displayed darker and a bright division image is displayed brighter in the image of one frame, thereby enhancing a contrast ratio and reducing power consumption.
1. A liquid crystal display (LCD) device, comprising:
a backlight unit having a plurality of division regions, each division region corresponding to a plurality of light sources;
an LCD panel for displaying a plurality of division images divided from an entire image of one frame, the division images corresponding to the division regions, respectively;
an image dividing part to divide the entire image of one frame into the plurality of division images corresponding to the number of the division regions;
a first calculator to calculate average brightness of the entire image of one frame;
a second calculator to calculate average brightness of each division image;
a backlight drive signal generator to compare the average brightness of the entire image of one frame with the average brightness of each division image and to generate a plurality of backlight drive signals for adjusting brightness of the plurality of division regions within one frame according to the comparing result; and
a backlight driver to generate a plurality of backlight drive voltages for adjusting the brightness of the plurality of division regions in response to the plurality of backlight drive signals such that light having the adjusted brightness is emitted from the plurality of light sources included in each division region,
wherein the backlight drive signal generator generates a backlight drive signal for adjusting a brightness brighter than or the same as the average brightness of the division image when the average brightness of the division image is greater than the average brightness of the entire image of one frame.
2. The LCD according to claim 1 , further comprising a division setting part to set the number of the plurality of division images.
3. The LCD according to claim 2 , wherein the division setting part sets the number of the plurality of division regions.
4. The LCD according to claim 1 , wherein the backlight driver includes an inverter to generate a backlight driving voltage according to the brightness of the each of the plurality of division images.
5. The LCD according to claim 1 , wherein the light sources comprise a plurality of CCFLs, EEFLs or LEDs.
6. A method for driving an LCD having a backlight unit having a plurality of division regions, each division region corresponding to a plurality of light sources, and an LCD panel for displaying a plurality of division images divided from an entire image of one frame, the division images corresponding to the division regions, respectively, comprising:
dividing the image of one frame into the plurality of division images corresponding to the number of the division regions;
calculating average brightness of the entire image of one frame;
calculating average brightness of each division image;
comparing the average brightness of the entire image of one frame with the average brightness of each division image and generating a plurality of digital backlight drive signals for adjusting brightness of the division regions within one frame according to the comparing result;
generating a plurality of backlight drive voltages for adjusting the brightness of the plurality of division regions in response to the plurality of backlight drive signals; and
emitting light having the adjusted brightness from the plurality of light sources included in each division region and providing the light having the adjusted brightness to the LCD panel,
wherein the step of generating a plurality of digital backlight drive signals includes generating a backlight drive signal for adjusting a brightness brighter than or the same as the average brightness of the division image when the average brightness of the division image is greater than the average brightness of the entire image of one frame.
7. The method according to claim 6 , further comprising setting the number of the division regions.
8. The method according to claim 7 , wherein the light sources comprise a plurality of CCFLs or EEFLs or LEDs.
9. A liquid crystal display (LCD) device, comprising:
a backlight unit having a plurality of division regions, each division region corresponding to a plurality of light sources;
an LCD panel for displaying a plurality of division images divided from an entire image of one frame, the division images corresponding to the division regions, respectively;
an image dividing part to divide the entire image of one frame into the plurality of division images corresponding to the number of division regions;
a first calculator to calculate average brightness of the entire image of one frame;
a second calculator to calculate average brightness of each division image;
a backlight drive signal generator to compare the average brightness of the entire image of one frame with the average brightness of each division image and to generate a plurality of backlight drive signals for adjusting brightness of the plurality of division regions within one frame according to the comparing result; and
a backlight driver to generate a plurality of backlight drive voltages for adjusting the brightness of the plurality of division regions in response to the plurality of backlight drive signals such that light having the adjusted brightness is emitted from the plurality of light sources included in each division region,
wherein the backlight drive signal generator generates a backlight drive signal for adjusting a brightness darker than the average brightness of the division image when the average brightness of the division image is smaller than the average brightness of the entire image of one frame.