Patent ID: 7969663

Claim:
A projection objective for imaging a pattern, arranged in an object plane of the projection objective, into an image plane of the projection objective, comprising: a first lens group following the object plane and of negative refractive power; a second lens group directly following the first lens group and of positive refractive power; a third lens group directly following the second lens group and of negative refractive power; a fourth lens group directly following the third lens group and of positive refractive power; a fifth lens group directly following the fourth lens group and of positive refractive power; and a system diaphragm that is arranged in a transition region from the fourth lens group to the fifth lens group, wherein the fourth lens group has an entrance surface that lies in the vicinity of a point of inflection of a marginal ray height between the third lens group and the fourth lens group, and no negative lens of substantial refractive power is arranged between the entrance surface and the system diaphragm, and wherein the fifth lens group has exclusively lenses of positive refractive power.