Patent ID: 8300211

Claim:
A catadioptric projection objective for microlithography and configured to image an object field in an object plane onto an image field in an image plane, comprising: a first partial objective configured to image the object field onto a first real intermediate image, a second partial objective configured to image the first intermediate image onto a second real intermediate image, and a third partial objective configured to image the second intermediate image onto the image field, wherein the second partial objective has exactly one concave mirror and at least one lens, wherein the projection objective has a first folding mirror configured to deflect the radiation from the object plane toward the concave mirror and a second folding mirror configured to deflect the radiation from the concave mirror toward the image plane, wherein the projection objective forms exactly two real intermediate images, wherein the projection objective has a numerical aperture of greater than 1.0 in the image plane, and wherein a minimum distance between an optically utilized region of a mirror surface of the concave mirror and an optically utilized region of a surface, which faces the concave mirror, of a lens adjacent to the concave mirror is greater than 20 mm.