RELIEF TYPE DIFFRACTION OPTICAL ELEMENT, MOLD FOR MANUFACTURE OF RELIEF TYPE DIFFRACTION OPTICAL ELEMENT AND OPTICAL SYSTEM USING RELIEF TYPE DIFFRACTION OPTICAL ELEMENT

摘要

PROBLEM TO BE SOLVED: To provide a relief type diffraction optical element such as a diffraction type lens which has high strength at its focusing point and is easily manufactured. ;SOLUTION: This relief type diffraction optical element has a saw-tooth cross-section shape in which the tilt angle of a relief surface is constant in one zone and the maximum height t_c of the relief shape in a center zone 7 is lower than the maximum height t_g of relief shapes in the other zones. Even when the number of zones is small or when the number of zones that a luminous flux actually passes through is small, the strength at a focusing point is high, the resolution is good and the manufacture is easy.;COPYRIGHT: (C)1999,JPO