Fresnel lens and Fresnel lens formation die and Fresnel lens production manner, in production mannered null optical axis direction

摘要

PROBLEM TO BE SOLVED: To improve optical performance of a Fresnel lens, by suppressing occurrence of an iridescent surface in the Fresnel lens.;SOLUTION: In cutting process which generates orbicular zones of the Fresnel lens composed of an optical function surface 21 and a vertical plane 22 by cutting into a workpiece 20 rotating around an optical axis (Z-axis) with a tool 7 in an optical axis direction, optical performance of the Fresnel lens is improved, by irregularly changing tool-cutting speed V of the tool 7 in the optical axis direction to form a cutter mark 23a having an irregular pitch P1 and preventing occurrence of the iridescent surface on the vertical plane 22 and reflection on the optical function surface 21 resulting from formation of regular cutter marks.;COPYRIGHT: (C)2011,JPO&INPIT