| 摘要 |
A Fresnel lens comprises a first surface, and a second surface being the reverse side surface of the first surface and having a plurality of lens surfaces. Each lens surface is configured from a part of a side surface of an elliptical cone, which has an apex located on the second surface side and a bottom surface located on the first surface side. Here, in the Fresnel lens, any normal line intersecting with the lens surface configured from the part of the side surface of the elliptical cone among normal lines of respective points on the first surface is non-parallel to a central axis of the elliptical cone corresponding to the lens surface with which the any normal line intersects. |
