Patent ID: 8355034

Claim:
A driving method for local dimming of a Liquid Crystal Display (LCD) device, comprising: dividing a frame into a plurality of blocks corresponding to a plurality of dimming blocks into which a backlight unit is divided so that the backlight unit is driven on a block basis; calculating an average value of each color in a block by analyzing image data of the block and determining, for the block, a local dimming value of each color corresponding to the average value of the color; detecting a maximum value among the average values of respective colors in the block and determining a luminance local dimming value corresponding to the maximum value of the block; calculating a number of achromatic color pixels in the block by analyzing the image data of the block, wherein a maximum value of each pixel is compared with the product between a minimum value of the pixel and a predetermined constant, and when the maximum value is less than the product, it is determined that the pixel is the achromatic color pixel; calculating a gain value for the block based on a ratio of the number of achromatic color pixels to a total number of pixels in the block; determining whether the block is a chromatic color area or an achromatic color area by comparing the gain value with a predetermined threshold; selecting the local dimming value of each color in the block and outputting the local dimming value of each color in the block, when the block is determined to be a chromatic color area; selecting the luminance local dimming value of the block and outputting the luminance local dimming value of the block, when the block is determined to be an achromatic color area; driving a plurality of Light Emitting Diodes (LEDs) corresponding to the block in the backlight unit on a color basis according to the local dimming value of each color in the block, when the local dimming value of each color in the block is output; and driving the plurality of LEDs corresponding to the block in the backlight unit on a color basis using the same luminance local dimming value, when the luminance local dimming value of the block is output.