Patent ID: 9097981
Filing Date: 2015-08-04
Classification: G02B,G03F

Abstract:
1. An illumination optical system which illuminates a plane to be illuminated with illumination light from a light source, the illumination optical system comprising, in order from the light source side: an optical element having a plurality of optical surfaces for splitting the illumination light into a plurality of beams; a first optical system which condenses the plurality of the beams and guides the condensed plurality of the beams to a predetermined plane, the first optical system refocusing the plurality of beams split by the optical element such that first paths of the plurality of beams prior to entering the first optical system are different from second paths of the plurality of beams after exiting the first optical system; a spatial optical modulator arranged on the predetermined plane and having a plurality of reflecting optical elements each of which has a movable reflection surface arranged to receive a respective beam of the plurality of beams traversing the second paths; and a second optical system arranged to distribute a plurality of light beams from the movable reflection surface of each of the reflecting optical elements at a pupil position of the illumination optical system or a position optically conjugate with the pupil position and to form a spatial light distribution at the pupil position or the position optically conjugate with the pupil position.