Patent ID: 8004658
Filing Date: 2011-08-23
Classification: G02B,G03F

Abstract:
1. An illumination optical apparatus that illuminates a surface to be illuminated, with a light beam from a light source, the illumination optical apparatus comprising: a diffractive optical element disposed in an optical path between the light source and the surface to be illuminated; an optical integrator disposed in an optical path between the diffractive optical element and the surface to be illuminated; and a beam damper disposed at a position in the optical path between the diffractive optical element and the optical integrator, where zero-order light from the diffractive optical element is focused, wherein an optical element disposed in an optical path between the diffractive optical element and the beam damper is fixed, and wherein an optical system disposed in an optical path between the beam damper and the optical integrator includes a movable optical element.