Patent ID: 7382540

Claim:
A refractive projection objective for projecting a pattern arranged in an object plane of the projection objective into an image plane of the projection objective with the aid of ultraviolet light of a prescribed operating wavelength at an image side numerical aperture NA>0.7 comprising: a multiplicity of optical elements which are arranged along an optical axis; and a system diaphragm arranged at a distance in front of the image plane; the projection objective being designed as a purely refractive single-waist system with a first convexity near the object plane, a second convexity near the image plane and a waist therebetween, the first convexity having a maximum diameter denoted by D1, and the second convexity having a maximum diameter denoted by D2, where 0.8<D 1 /D 2 <1.1; a negative group having an effective curvature with a concave side directed towards the image being arranged in a region of divergent radiation between the waist and the system diaphragm; and the negative group comprising at least one meniscus lens with negative refractive power, and a concave surface directed towards the image plane.