Patent ID: 7813055

Claim:
A light receiver comprising: a Fresnel lens for collecting light signals incident thereon; and a light receiving element disposed closer to the Fresnel lens than a focal point of the Fresnel lens, the light receiving element receiving the light signals collected by the Fresnel lens, wherein the Fresnel lens comprises: a lens surface group having a plurality of lens surfaces; and a back cut surface group having a plurality of back cut surfaces connecting the lens surfaces, the back cut surfaces being inclined with respect to a center axis of the Fresnel lens, wherein the lens surface group includes: a first lens surface group formed of lens surfaces having a first focal length; and a second lens surface group formed of lens surfaces having a second focal length, and wherein the first focal length is shorter than the second focal length, the first lens surface group is disposed close to a center of the Fresnel lens, and the second lens surface group is disposed outside the first lens surface group.