Patent ID: 8305388

Claim:
A display device, which converts three color input image signals into three color output image signals and four output image signals including a white output image signal and displays the converted signals, comprising: an arranging unit to arrange the input image signals in a gray order and to obtain a maximum input gray, a middle input gray, and a minimum input gray; a gamma converter to gamma-convert the maximum input gray, the middle input gray, and the minimum input gray and to generate a maximum input luminance, a middle input luminance, and a minimum input luminance; a calculator to obtain a white output luminance from the minimum input luminance, and to convert the maximum input luminance, the middle input luminance, and the minimum input luminance based on the white output luminance to obtain a maximum output luminance, a middle output luminance, and a minimum output luminance; a de-gamma converter to de-gamma-convert the white output luminance, the maximum output luminance, the middle output luminance, and the minimum output luminance and to obtain a white output gray, a maximum output gray, a middle output gray, and a minimum output gray; a rearranging unit to rearrange the arrangement order of the white output gray, the maximum output gray, the middle output gray, and the minimum output gray and to generate the four color output image signals; and four color pixels to perform a display operation according to the four color output image signals, wherein the white output luminance is a non-linear function of the minimum input luminance with respect to at least some values, and wherein, when the minimum input luminance is smaller than a predetermined value, the white output luminance may be zero, and when the minimum input luminance is larger than the predetermined value, the white output luminance comprises the same value as the minimum input luminance.