| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a relatively compact projection optical system having superior imaging performance having various aberrations such as a chromatic aberration and a field curvature excellently corrected, and capable of securing a large effective image-side numerical aperture by excellently suppressing reflection loss on an optical plane.SOLUTION: A cata-dioptric type projection optical system for forming a reduced image of a first plane R on a second plane W comprises at least two reflecting mirrors CM1 and CM2 and transparent members L11 to L217. The cata-dioptric type projection optical system comprises an arcuate effective imaging region not including an optical axis AX of the projection optical system. In the cata-dioptric type projection optical system, a condition of 1.05<R/Y0<12 is satisfied, where R is size of a radius of curvature of an arc defining the effective imaging region and Y0 is a maximum image height on the second plane.</p> |
