Optical device as well as projector unit and rear projector system using the same

摘要

An optical device including an illuminant for emitting light; light condensing element composed of a reflecting mirror whose shape of reflecting plane is of rotational secondary curved surface and a condenser lens for converging approximately parallel fluxes; a mixing rod whose section is quadrangle, first lens element composed of at least one lens; and a reflecting optical element which is disposed near the position where a plurality of tertiary illuminants are formed and which reflects light in a desired direction. This optical device allows a distribution of illuminance whose intensity is highly uniform to be obtained even when a light flux is inputted from a direction inclined from the normal direction of the plane-to-be-illuminated by illuminating the optical device disposed out of an optical axis of the illuminator.