OPTICAL INTEGRATOR, ILLUMINATING OPTICAL DEVICE, EXPOSURE APPARATUS AND DEVICE MANUFACTURING METHOD

摘要

Provided is an optical integrator having a plurality of wavefront splitting elements arranged two-dimensionally parallel to each other. In the optical integrator, a beam group diagonally entered the optical axis center of an incoming surface of the wavefront splitting element is outputted parallel to the optical axis from the wavefront splitting element. In a prescribed number of wavefront splitting elements (100A) among the wavefront splitting elements, at least one curved optical surface (100a, 100b) of the wavefront splitting elements (100A) passes the optical axis center (100aa) of the incoming surface (100a) of the wavefront splitting elements (100A) and inclines with an axial line (104) in a prescribed direction (x direction) that orthogonally intersects with an optical axis (Axe) at the center.