Projector and prism used therein

A projector that projects images and displays the images, comprising:

• an illumination optical system that emits illumination light;
• an optical modulator having a light illumination surface that controls an emitting direction of light applied to the light illumination surface in accordance with image information, to modulate the light applied to the illumination surface;
• a projection optical system that projects light emitted from the optical modulator;
• and
• a prism provided between the optical modulator and the projection optical system, the prism having a selective reflection/transmission surface that reflects the illumination light emitted from the illumination optical system to cause the illumination light to impinge upon the light illumination surface at a predetermined angle, and that transmits the light emitted from the optical modulator to the projection optical system, the selective reflection/transmission surface being formed such that, when optical paths of the illumination light are projected onto a plane parallel to the light illumination surface, an inclination of a central axis of the illumination light emitted from the illumination optical system and impinging upon the selective reflection/transmission surface is different from an inclination of an central axis of the illumination light reflected by the selective reflection/transmission surface and impinging upon the light illumination surface.