Patent ID: 7786973

Claim:
An image display device, comprising: a backlight module having a plurality of backlight regions, each of the backlight regions comprising an adjustable luminance unit, each of the luminance units having a basis luminance value; a separating unit for separating an input image signal into a plurality of image region signals, each of the image region signals corresponding to one of the backlight regions; a signal-processing unit for receiving the image region signals and transforming the image region signals into a plurality of output image signals, respectively; and a modulation unit for adjusting the basis luminance values to a plurality of output luminance values, respectively, according to the image region signals, respectively; wherein each of the basis luminance values and the corresponding image region signal cooperatively define a chromaticity and brightness, and the corresponding output luminance value and the corresponding output image signal cooperatively define substantially the same chromaticity and brightness; and wherein the signal-processing unit transforms each of the image region signals into the corresponding output image signal through linear magnification according to a maximum gray scale value of said image region signal wherein the modulation unit adjusts each of the basis luminance values to the corresponding output luminance value according to the maximum gray scale values of said image region signals; having a gamma curve value (γ) and a gamma curve, for expressing a relation between a luminance value (B) and a gray scale value (G) of the display, the relation being B=Gamma y (G); wherein, for an i th backlight region, the output luminance value B 2i is represented by B 2i =100%×Gamma y (M i ), and the output image signal G 2i is represented by G 2i =G 1i ×255/M i , where G 1i is the image region signal corresponding to said i th backlight region, and M i is the maximum gray scale value of said image region signal G 1i .