Patent ID: 6868223
Filing Date: 2005-03-15
Classification: G02B,G03F

Abstract:
1. An illumination apparatus for using a beam emitted from a light source to illuminate an object area, said illumination apparatus comprising: a condensing optical system for condensing the beam emitted from the light source; and a reflection type optical integrator located between said condensing optical system and the object area, said optical integrator having an m-gonal (where m is an even number) sectional shape, forming multiple pairs of opposing reflection surfaces, and reflecting the beam between the multiple pairs of opposing reflection surfaces, wherein a length L in an axial direction of said reflection type optical integrator meets the following equations: where n is a refractive index of a medium between the reflection surfaces, Φ is a distance between the reflection surfaces, θ is an angle of divergence when the beam emitted from said condensing optical system enters the reflection type optical integrator, C is a constant determined in relation to the sectional shape of said reflection type optical integrator, and A is a natural number.