LENS SYSTEM HAVING DIFFRACTION TYPE OPTICAL ELEMENT

摘要

PROBLEM TO BE SOLVED: To provide a lens system in which astigmatism and axial chromatic aberration are satisfactorily compensated in the lens system having a lens equipped with a diffraction type optical element. SOLUTION: The lens system has the lens which has a pair of lens faces with curvature and which includes the diffraction type optical element on the lens face. At least at one half image angle, a relation between astigmatism quantity B of an (e) line and axial chromatic aberration quantity A of a C line and the e line can be expressed by formula: 0.5×¾B¾<¾A¾<3.0×¾B¾. COPYRIGHT: (C)2008,JPO&INPIT