Patent ID: 8319714

Claim:
A display device comprising: a pixel portion having a plurality of pixel electrodes and an opposite electrode with liquid crystal molecules interposed therebetween over a first surface of a substrate, wherein the pixel portion displays an image including at least a white display region and a black or gray display region based on a video signal; a backlight unit provided on a second surface of the substrate, the backlight unit supplying light to the pixel portion; and a driver circuit portion comprising a control circuit, the driver circuit portion inputted with the video signal and controls the backlight unit, wherein in the image, all white display regions are displayed at the highest grayscale with the largest number of grayscale levels and all black display regions are displayed at the lowest grayscale with the smallest number of grayscale levels, and wherein control circuit comprises: a determining circuit configured to determine a ratio of the white display region to the black or gray display region based on the video signal; a converter circuit configured to perform an addition process to raise luminance of the white display region and a subtraction process to decrease luminance of a gray display region based on an output of the determining circuit, and wherein a controller is configured to supply a signal to lower the greyscale of the gray display region to a signal line driving circuit when a signal to perform a high grayscale display is inputted from the control circuit to a power source of the backlight unit.