Patent ID: 8947635
Filing Date: 2015-02-03
Classification: G02B,G03F

Abstract:
1. An illumination optical system for illuminating an illumination target surface with light from a light source, comprising: an optical integrator which distributes the light from the light source on an illumination pupil plane in an illumination optical path of the illumination optical system; a transmission section which is arranged on the illumination pupil plane, the transmission section having a transmittance characteristic varying according to positions of the light incident thereinto; and a movement mechanism which moves the transmission section along an optical-axis direction of the illumination optical system in said illumination pupil plane, wherein the transmission section comprises a first transmission part arranged in an optical path of a first illumination beam passing through a first region in the illumination pupil plane, and a second transmission part arranged in an optical path of a second illumination beam passing through a second region in the illumination pupil plane, the second region being different from the first region.