Patent ID: 8934086
Filing Date: 2015-01-13
Classification: G02B,G03F

Abstract:
1. An illumination optical system for distributing light from a light source on an illumination pupil and illuminating an illumination target surface with light having passed through the illumination pupil, comprising: a reflecting surface which reflects the light from the light source, the reflecting surface causing a phase difference between p-polarized light and s-polarized light, polarization directions of the p-polarized light and s-polarized light being defined to the reflecting surface; a polarization converting member which is positioned optically upstream of the reflecting surface and converts a polarization state of the light from the light source so that polarization states at different positions on the illumination pupil are different from each other, at least one of the polarization states at the different positions including a polarization direction different from the p-polarized light and the s-polarized light on the reflecting surface; and a phase modulating member which is arranged in an optical path between the polarization converting member and the reflecting surface, the phase modulating member changing a phase difference between first linearly-polarized light and second linearly-polarized light, to reduce the phase difference between the p-polarized light and the s-polarized light caused by the reflecting surface, the first linearly-polarized light passing through the phase modulating member and having a polarization direction corresponding to the p-polarized light, the second linearly-polarized light passing through the phase modulating member and having a polarization direction corresponding to the s-polarized light.