Patent ID: 8562140
Filing Date: 2013-10-22
Classification: G02B,H04N

Abstract:
1. An illumination optical system for illuminating, with light from a light source, a surface to be illuminated via a polarization separation surface which is arranged at an inclination to an optical axis of the illumination optical system comprising, in order from the light source side: a first front side cylindrical lens array; a first rear side cylindrical lens array; a second front side cylindrical lens array; and a second rear side cylindrical lens array, wherein when a section that is parallel with a normal line of the polarization separation surface and the optical axis of the illumination optical system is defined as a second section and a section that is perpendicular to the second section and parallel with the optical axis of the illumination optical system is defined as a first section, the first front side cylindrical lens array has a plurality of cylindrical lenses having a refractive power in the first section, the first rear side cylindrical lens array has a plurality of cylindrical lenses having a refractive power in the first section, the second front side cylindrical lens array has a plurality of cylindrical lenses having a refractive power in the second section, and the second rear side cylindrical lens array has a plurality of cylindrical lenses having a refractive power in the second section, and wherein a light beam diameter in the first section of an incident light to the first rear side cylindrical lens is larger than a light beam diameter in the second section of an incident light to the second rear side cylindrical lens.