Patent ID: 8390656
Filing Date: 2013-03-05
Classification: G09G

Abstract:
1. An image display device having a function of controlling a luminance of a backlight, the image display device comprising: a display panel including a plurality of display elements; a backlight including a plurality of light sources of three RGB colors; an in-area maximum luminance obtaining unit that divides an input image into a plurality of areas and obtains, based on a portion of the input image in each area, maximum luminances for the respective RGB colors in the area, as first light-emission luminances; a weighting coefficient calculating unit that determines weighting coefficients to be used in calculation of second light-emission luminances, based on first light-emission luminances for the three RGB colors in the plurality of areas, the second-light emission luminances indicating luminances of light sources of the three RGB colors in each area upon light emission; a light-emission luminance correcting unit that extracts, in each area, a color with a highest first light-emission luminance among the three RGB colors as a reference color, and determines, in the each area, second light-emission luminances for colors other than the reference color based on correction luminances obtained by multiplying the first light-emission luminance for the reference color by predetermined coefficients and the weighting coefficients; a display data calculating unit that obtains display data for controlling light transmittances of the display elements, based on backlight control data and the input image, the backlight control data including data representing first light-emission luminances for the reference color and data representing second light-emission luminances for the colors other than the reference color which are determined by the light-emission luminance correcting unit; a panel drive circuit that outputs, based on the display data, signals for controlling the light transmittances of the display elements to the display panel; and a backlight drive circuit that outputs, based on the backlight control data, signals for controlling luminances of the light sources to the backlight.