Patent ID: 7869121
Filing Date: 2011-01-11
Classification: G02B

Abstract:
1. An objective employed for use in imaging a specimen, comprising: a lens group comprising at least one focusing lens configured to receive light energy and form focused light energy, said focused light energy forming an intermediate image; and a catadioptric arrangement comprising a curved mirror element axially aligned with said lens group and positioned to receive the intermediate image and form controlled light energy; wherein the catadioptric arrangement is positioned between the lens group and the specimen and consists of the curved mirror element and at most two additional elements positioned between the curved mirror element and the specimen, the at most two additional elements comprising an aspheric convex surface positioned between the curved mirror element and a relatively flat reflecting surface configured to reflect light energy back toward the curved mirror element; and further wherein the lens group and catadioptric arrangement comprising the aspheric convex surface each have a maximum element diameter for all elements in the lens group and catadioptric arrangement comprising the aspheric convex surface of less than approximately 49 millimeters, and are collectively configured to provide a field size in excess of 0.8 mm and a numerical aperture of up to approximately 0.97 in air.