Illumination system having first and second lens arrays including plano-convex lenses wherein some lenses in the second array include a first and a second lens element, projection-type display apparatus, and optical integrator

Abstract

In at least one embodiment of the disclosure, an illumination system includes a light source that emits an illumination light flux. A first lens array has a plurality of first small lenses arranged therein. The first small lenses divide the illumination light flux emitted from the light source into a plurality of segmental light fluxes. A second lens array has a plurality of second small lenses arranged therein. The second small lenses have a one-to-one correspondence with the first small lenses and are configured to receive the segmental light fluxes exiting from the first small lenses. At least some of the second small lenses each include a plurality of lens elements disposed in a surface direction that is the same as the second small lenses. A superimposing lens superimposes on an illuminated area the segmental light fluxes exiting from the plurality of second small lenses.