| 摘要 |
PROBLEM TO BE SOLVED: To provide a diffraction lens which is bright and whose diffraction efficiency is successfully maintained.SOLUTION: The diffraction lens includes an inner element part and an outer element part. In the inner element part, a plurality of surface ruling type gratings formed concentrically around a concentric axis perpendicular to the surface of a substrate are arranged so that the interval of the gratings is gradually narrower as it is away from the axis. In the outer element part, VP gratings including a plurality of trenches extending from the surface of the substrate in a depth direction, so as to surround the inner element part concentrically and a filler with which the trenches are filled and which has a refractive index different from that of the substrate are formed so that the interval of the gratings is gradually narrower as it is away from the axis. |
