Patent ID: 9423698
Filing Date: 2016-08-23
CPC Classification: G02B,G03F

Claim Text:
1. An illumination optical apparatus which illuminates an object with illumination light, the apparatus comprising: a light deflecting member arranged in an optical path of the illumination light, which deflects the illumination light; a lens element arranged in the optical path of the illumination light from the light deflecting member; a birefringent member including a birefringent material arranged in the optical path of the illumination light from the lens element to change a polarization state of the illumination light; and an optical integrator arranged in the optical path between the birefringent member and a pupil plane of the illumination optical apparatus, wherein the light deflecting member sets an incidence angle of the illumination light to the object on the basis of a deflection angle of the illumination light provided with the light deflecting member, the deflection angle being adjustable, and the birefringent member includes different thicknesses of the birefringent material at different incidence positions such that the illumination light incident on the birefringent member in a first linear polarization state having a single polarization direction is in a second linear polarization state on the pupil plane, the second linear polarization state having a polarization direction being substantially coincident with a circumferential direction about an optical axis of the illumination optical apparatus.