Patent ID: 8670006

Claim:
A local dimming driving method of a liquid crystal display device, the local dimming driving method comprising: divisionally driving all of a plurality of blocks of a backlight unit using a maximum luminance signal and measuring luminance per block; setting one of the plurality of blocks as a reference block, detecting luminance deviations between the reference block and the residual blocks, setting an offset value per block for compensating for the detected luminance deviations per block, and storing the offset value per block in a memory; analyzing input image data in units of blocks corresponding to the plurality of blocks of the backlight unit respectively, detecting a representative value per block, and determining a dimming value per block according to the representative value per block; correcting the dimming value per block using the offset value per block to output a corrected diming value per block; controlling the luminance of the backlight unit on a block-by-block basis using the corrected dimming value per block; analyzing light quantity of a light source of a block of the backlight unit and storing light profile data in the memory; calculating a gain value using the light profile data from the memory and the dimming value per block; and compensating the input image data using the gain value, wherein: the gain value is calculated as a ratio between a first total light quantity per pixel when maximum luminance of the backlight unit and a second total light quantity per pixel when luminance of the backlight unit controlled by local dimming, the first total light quantity per pixel is calculated as a sum of light quantities reaching each pixel from the light sources of blocks neighboring the each pixel using the light profile data, when the luminance of the backlight unit has a maximum value, and the second total light quantity per pixel is calculated as a sum of light quantities reaching each pixel from the light sources of blocks neighboring the each pixel using the light profile data and the dimming value per block, when the luminance of the backlight unit is controlled on the block-by-block basis according to the dimming value per block, thereby multiplying the light quantities reaching each pixel from the light sources of blocks neighboring the each pixel by the local dimming value per block to sum multiplied values.