| 摘要 |
<p>An optical integrator is able to keep down a light-quantity loss in modified illumination with an illumination optical apparatus. An optical integrator (4) of a wavefront division type according to the present invention has a plurality of refracting surface regions (4a, 4b) which refract incident light, and a plurality of deflecting surface regions (4c, 4d) provided corresponding to the plurality of refracting surface regions and adapted for changing a traveling direction of the incident light. The plurality of refracting surface regions include a plurality of first refracting surface regions (4a) having an arcuate contour with the center projecting in a first direction (-X-direction), and a plurality of second refracting surface regions (4b) having an arcuate contour with the center projecting in a second direction (+X-direction).</p> |
