Patent ID: 8896938
Filing Date: 2014-11-25
Classification: G02B

Abstract:
1. A catadioptric lens system comprising, in order of light travel: a first lens group that includes a concave mirror and a convex mirror and has a positive refractive power; a second lens group that is positioned on the image side of the concave mirror and has a negative refractive power, the second lens group having at least one second group lens; and a third lens group that has a positive refractive power, the third lens group having at least one third group lens, wherein the first lens group has a plurality of first group lenses on the image side of the concave mirror, and at least one of the plurality of the first group lenses is movable only in a direction perpendicular to an optical axis, the optical axis defining a longitudinal direction and wherein the catadioptric lens system is operable in a focused state and during a focusing state such that, in the focused state, the first lens group, the second lens group and the third lens group are stationary along the optical axis in the longitudinal direction while the at least one of the plurality of the first group lenses is configured to move in the direction perpendicular to the optical axis and, during the focusing state, the second lens group moves along the optical axis in the longitudinal direction between the first lens group and the third lens group while the first lens group and the third lens group remain stationary along the optical axis in the longitudinal direction and the at least one of the plurality of the first group lenses remains configured to move in the direction perpendicular to the optical axis.