Patent ID: 8188966

Claim:
An image display device capable of adjusting brightness, the image display device comprising: a brightness determining unit configured to: receive image data applied from outside; determine a brightness of the applied image data; and output a backlight selection signal and a contrast selection signal corresponding to the determined brightness of the applied image data; a backlight control unit that is connected to the brightness determining unit, the backlight control unit being configured to: receive the backlight selection signal; and output a backlight driving voltage for supplying backlight with a brightness corresponding to the backlight selection signal; a contrast control unit that is connected to the brightness determining unit, the contrast control unit being configured to receive the applied image data and the contrast selection signal from the brightness determining unit, and output an image output signal, the image output signal being converted from an image signal including the applied image data of which the contrast is adjusted by the contrast control unit to correspond to the contrast selection signal, the contrast control unit comprising: first to fifth calculation means that shift the applied image data by one bit, two bits, three bits, four bits, and five bits, respectively; and a contrast calculating means that is connected to the first to fifth calculation means and the brightness determining unit, the contrast calculating means being configured to selectively add the image data output from the first to fifth calculation means depending on preset backlight brightness combinations such that a contrast of the image data corresponds to the contrast selection signal output from the brightness determining unit, thereby generating the image signal of which the contrast is adjusted; and an image display unit that is connected to the backlight control unit and the contrast control unit, the image display unit being configured to: receive the backlight driving voltage and the image output signal; and display an image in which the brightness of the backlight and the contrast of the applied image data are respectively adjusted.