| abstract |
An imaging optical unit serves for imaging an object field in an image field. The imaging optical unit has an obscured pupil (21). This pupil (21) has a center (Z), through which a chief ray of a central field point passes. The imaging optical unit furthermore has a plurality of imaging optical components. A gravity center (SP) of a contiguous pupil obscuration region (18) of the imaging optical unit lies decentrally in the pupil (21) of the imaging optical unit. According to a further aspect, the imaging optical unit is embodied in a catoptric manner, with a last mirror with a passage opening for the passage of imaging light. An edge region of a reflection surface of the last mirror, which edge region surrounds the passage opening, is used contiguously for reflecting the imaging light. A penultimate mirror in the imaging beam path is embodied with a reflection surface which is used in a closed fashion, i.e. without an opening. The passage opening is arranged in such a way that this generates a pupil obscuration region (18), which does not lie centrally in the pupil (21) of the imaging optical unit. Such imaging optical units result in a well corrected imageable field with, at the same time, a high imaging light throughput. |