Patent ID: 6208473
Filing Date: 2001-03-27
Classification: G02B,G03F

Abstract:
A catadioptric projection lens having an object plane and an image plane, the lens comprising in order from the object plane to the image plane:a.) a first lens group having one or more refractive lens elements and disposed along a first optical axis;b.) a first mirror which creates a second optical axis that is not parallel to said first optical axis;c.) a beam splitter, disposed along said second optical axis, which creates a third optical axis that is parallel to said first optical axis;d.) a second lens group having one or more refractive lens elements and a concave mirror, said second lens group disposed along said third optical axis adjacent said beam splitter and opposite the image plane;e.) a third lens group having one or more refractive lens elements and disposed along said third optical axis immediately adjacent the image plane; andf.) wherein all refractive lens elements in the catadioptric projection lens have optical axes that extend in parallel.