Patent ID: 8432412

Claim:
An image display apparatus comprising: (A) an image display panel having a two-dimensional matrix with (P×Q) pixels each including a first sub-pixel for displaying a first elementary color, a second sub-pixel for displaying a second elementary color, a third sub-pixel for displaying a third elementary color and a fourth sub-pixel for displaying a fourth color; and (B) a signal processing section configured to receive a first sub-pixel input signal, a second sub-pixel input signal and a third sub-pixel input signal, and to output a first sub-pixel output signal used for determining the display gradation of said first sub-pixel, a second sub-pixel output signal used for determining the display gradation of said second sub-pixel, a third sub-pixel output signal used for determining the display gradation of said third sub-pixel as well as a fourth sub-pixel output signal used for determining the display gradation of said fourth sub-pixel, and said signal processing section carries out the following processes of finding a saturation S and said lightness value V(S) for each of a plurality of pixels on the basis of the signal values of sub-pixel input signals in said pixels, and finding an extension coefficient α 0 on the basis of at least one of ratios V max (S)/V(S) found in said pixels.