Polarized beam splitter and an illumination optical system and a projector provided with a polarized beam splitter

Abstract

A projector includes: imaging members producing primary color light images; an illumination optical system for illuminating the imaging members; an image combining optical system for combining the color light images; and a projection optical system for projecting a combined color light image onto a screen. The illumination optical system includes a beam splitter for splitting a visible light beam into two components having perpendicular polarization directions; a converter for making the polarization directions of the components coincide; and a color separator for separating light from the converter into rays of the plurality of primary colors. The beam splitter can have a first transparent base; a second transparent base; and a polarizing multilayered film placed between the first and second transparent bases. The polarizing multilayered film includes high refraction layers each having a refractive index n,and low refraction layers each having a refractive index n,lower than the refractive index n,, the high refraction layers and the low refraction layers being alternately laminated to one another. A maximum efficiency incident angle for the polarization splitting film is shifted from an incident angle of a main ray from the light source in order to make an illumination nonuniformity.