Patent ID: 6739724
Filing Date: 2004-05-25
Classification: G02B,H04N

Abstract:
An illumination optical system, comprising:a luminous flux division optical element which divides light from a light source into a plurality of pieces of partial luminous fluxes and collects each of the partial luminous fluxes; a color light separation optical element which separates each of the partial luminous flux into first color partial luminous flux and second color partial luminous flux, and emits the first color partial luminous flux and the second color partial luminous flux in at least one of different directions with each other and in a direction parallel to each other; a polarization change element which includes a polarization beam splitter array in which a plurality of polarization separation films and a plurality of reflective films are arranged alternately, and a polarization direction rotation element which is disposed either at a position where light transmitted through the polarization separation film is emitted or at a position where light reflected by the reflective film is emitted, the first color partial luminous flux incident on the polarization separation film being uniformed in a first polarization direction to be emitted, and the second color partial luminous flux incident on the reflective film being uniformed in a second polarization direction different from the first polarization direction to be emitted; a transmission optical element which is disposed either at an incident side or at an emitting side of the polarization change element, that transmits an image formed by the luminous flux division optical element to an illuminated area; and a superposition optical element that superposes the partial luminous fluxes emitted from the polarization change element at the illuminated area.