An IMD mold for producing a foil-decorated plastic part contains a half mold facing the foil and a half mold facing away from the foil. An indicator portion provided in the resin key top is illuminated with light from an internal light source provided below the key seat, and the light is emitted from the inside to the outside of the cover member through the indicator portion. Such a 1 dimensional or 2 dimensional array of micromirror devices may be used as a spatial light modulator.