Patent ID: 7868963

Claim:
An optical modulation element unit comprising: a light-transmissive substrate; a film-type optical function member attached to the light-transmissive substrate; a reflective optical modulation element placed, at a predetermined distance, substantially parallel to the light-transmissive substrate; a cover member which surrounds a dustproof space between the light-transmissive substrate and the reflective optical modulation element; and a holding member which holds the light-transmissive substrate; wherein the holding member has an air guiding portion which guides an air flow to an air flow space along a first surface of the light-transmissive substrate, the first surface being a surface facing away from the reflective optical modulation element; wherein the cover member is formed so as not to surround the air flow space along the first surface; and wherein the film-type optical function member is attached to a second surface of the light-transmissive substrate, the second surface being a surface facing towards the reflective optical modulation element.