Patent ID: RE42570

Claim:
A catadioptric objective wherein a light beam is transmitted along a light path and said catadioptric objective defining an optical axis, said catadioptric objective comprising in sequence of travel of said light beam: a first lens group having a negative refractive power and arranged centered on said optical axis; a first concave mirror having a central cutout and being arranged centered on said optical axis downstream of said first lens group; a second concave mirror having a central cutout and being arranged centered on said optical axis downstream of said first concave mirror; said first and second concave mirrors being disposed so as to face each other; a second lens group having a negative refractive power and being arranged centered on said optical axis downstream of said second concave mirror; said first lens group having a first plurality of lenses arranged upstream of said first concave mirror; said second lens group having a second plurality of lenses arranged downstream of said second concave mirror; and, one of said first and second plurality of lenses having at least one aspheric lens surface , wherein said catadioptric objective has an object end region and an image end region and said catadioptric objective further comprising a field lens group disposed in one of said object end region and said image end region, said field lens group having said aspheric lens surface .