摘要 |
An imaging optical system has a plurality of mirrors, which via a beam path for imaging light, image an object field in an object plane into an image field in an image plane. The imaging optical system has an exit pupil obscuration. At least one of the mirrors has no opening for passage of the imaging light. The fourth to last mirror in the beam path is concave, resulting in an imaging optical system having improved imaging properties without compromise in throughput. |