Patent ID: 8477286
Filing Date: 2013-07-02
Classification: G02B,G03B,G03F

Abstract:
1. A projection optical system configured to project an image of an object plane onto an image plane, said projection optical system comprising: a first optical element having an aspheric surface that is rotationally asymmetric with respect to an optical axis; a moving unit configured to move the first optical element in a direction perpendicular to the optical axis; and a second optical element having an aspheric surface and fixed on the optical axis, wherein the aspheric surface of the second optical element is configured to reduce an aberration due to the aspheric surface of the first optical element when the first optical element is located at a predetermined position, wherein the first optical element corrects an aberration of the projection optical system by moving away from the predetermined position in the direction perpendicular to the optical axis, and wherein the aspheric surface of the second optical element is not complementary to the aspheric surface of the first optical element.