Backlight unit assembly and liquid crystal display having the same and dimming method of thereof

PURPOSE: A backlight unit assembly, a liquid crystal display device having the same and a dimming method thereof are provided to improve the display quality of various images. CONSTITUTION: The dimming method of a liquid crystal display device comprises the following steps of: setting up plural lookup tables, which have different data to obtain the luminance corresponding to the same gray scale(S120); calculating the whole gray-level average of an image signal inputted into liquid crystal display panels and individual gray-level averages of each liquid crystal display panel(S130); selecting one of the lookup tables according to the whole gray-level average; and calculating data for obtaining the luminance corresponding to individual gray-level averages from the selected lookup table(S140).