Projector and prism used therein

Abstract

A projector of the type which uses an optical modulator that modulates light by controlling the emitting direction of light applied to a light illumination surface in accordance with image information is provided with a reduction in size. In the projector a prism has a selective reflection/transmission surface which reflects illumination light emitted from an illumination optical system and impinging thereupon, and causes the illumination light to impinge upon the light illumination surface of an optical modulator at a predetermined angle. The prism allows the modulated light emitted from the optical modulator to be transmitted therethrough and emits the light to the projection optical system. The selective reflection/transmission surface is formed such that when the optical path of the illumination light is projected onto a plane parallel to the light illumination surface, the inclination of the central axis of the illumination light emitted from the illumination optical system and impinging upon the selective reflection/transmission surface is different from the inclination of the central axis of the illumination light reflected by the selective reflection/transmission surface and impinging upon the light illumination surface.