Patent ID: 6765729
Filing Date: 2004-07-20
Classification: G02B,G03F

Abstract:
A catadioptric projection lens for projecting a pattern located on an object plane onto an image plane, wherein, between the object plane and the image plane, the following are arranged in the given order:a first objective part, which creates a ray; a physical beam splitter with a beam splitter surface, whereby the ray created by the first objective part is directed to the physical beam splitter; a mirror group receiving light directly from the beam splitter and returning light directly to the beam splitter, the mirror group having a refractive power and a concave mirror; and a second objective part with positive refractive power, which creates an image of the pattern on the image plane, wherein the refractive power of the mirror group is calculated such that a divergent beam incident on the mirror group is transformed into a convergent beam and the system aperture is located imagewise behind the concave mirror and is located between the beam splitter surface and the image plane; wherein no free-standing lens is placed between the beam splitter surface and the concave mirror.