Patent ID: 8497977
Filing Date: 2013-07-30
Classification: G03F

Abstract:
1. An optical integrator used in an illumination optical system that illuminates an illumination target surface with light from a light source, the optical integrator comprising: a first fly's eye optical system having a plurality of first optical elements arranged in parallel at a position optically conjugate with the illumination target surface in an optical path between the light source and the illumination target surface; and a second fly's eye optical system having a plurality of second optical elements arranged in parallel so as to correspond to the plurality of first optical elements in an optical path between the first fly's eye optical system and the illumination target surface, wherein a size D of the first fly's eye optical system and a distance K between a center of an array surface of the plurality of first optical elements and a center of a standard array surface of the plurality of second optical elements are determined so that each illumination region formed on the illumination target surface by a beam traveling via each first optical element and corresponding second optical element becomes close to a desired superimposed illumination region, and wherein there is no optical member having a power in an optical path between the second fly's eye optical system and the illumination target surface.