There is disclosed a display device using a color wheel having a color filter
Cw, in addition to normal color filters corresponding to the three primary colors.
The filter Cw has almost flat spectral transmission characteristics. Brightness
information included in a color image signal is quantized with (n+m) bits. Information
corresponding to the lower-order n bits is displayed by light transmitted through
the filter Cw. Information corresponding to the upper-order n bits is displayed
by light transmitted through the normal color filters. Only brightness information
to which the human eye is visually sensitive is reproduced by the filter Cw having
a lower transmissivity. This can eliminate a lack of the number of gray levels
due to a constraint on the minimum switching speed of a light valve. Furthermore,
the brightness little deteriorates.
