Patent ID: 6903802

Claim:
A projection exposure system defining an optical axis and comprising: an illuminating unit mounted on said optical axis for transmitting a light beam along said optical axis; a projection objective arranged on said optical axis downstream of said illuminating unit; a mask held in the beam path of said light beam between said illuminating unit and said projection objective; a substrate holder for holding a substrate in said beam path downstream of said projection objective; and, said projection objective defining a maximum lens diameter and including: a plurality of lenses defining an object plane and an image plane; at least two of said lenses having respective mutually adjacent lens surfaces which are aspheric to define a double asphere; said double asphere being mounted at a distance from said image plane corresponding at least to said maximum lens diameter; the lenses of said double asphere defining a mean lens diameter; and, said mutually adjacent lens surfaces being mounted at a spacing from each other which is less than half of said mean lens diameter.