The present disclosure relates to an image display unit and to a method of driving an image display unit, as well as to a signal generator, to a signal generation program, and to a signal generation method. A signal for a red sub-pixel signal, a signal for a green sub-pixel signal, a signal for a blue sub-pixel signal, and a signal for a white sub-pixel signal are generated based on an image signal for red display, an image signal for green display, and an image signal for blue display that are provided in accordance with an image to be displayed. Values of the red sub-pixel signal Rcvt, the green sub-pixel signal Gcvt, and the blue sub-pixel signal Bcvt are determined based on a first matrix and a second matrix, with use of a coefficient 'Purity', an additive-color-mixture matrix, and a purity coefficient '[Psi]', and a value of the white sub-pixel signal Wcvt is configured to be employed as a value of min (RnL, GnL, BnL). According to the invention, the luminance can be raised assuredly even in the case where display is performed by reflecting external light, etc.