Linear Fresnel Lens

Abstract

The Fresnel lens 1 includes a substrate 2 and a linear Fresnel lens structure 3 formed on at least one side of the surface of the substrate 2. The linear Fresnel lens structure 3 includes: a plurality of Fresnel lens surfaces 4 extending along the X direction and arranged in the Y direction; and a concave-convex structure 10 formed on a rising surface 5, the rising surface 5 connecting adjacent Fresnel lens surfaces 4, 4 in the Y direction. The concave-convex structure 10 has a plurality of protrusions 12, the protrusions 12 being repeatedly arranged on the rising surface 5 along the X direction at predetermined intervals P. Each protrusion 12 includes: a first diffusion surface 14 connected to the upper edge 4a of one of the adjacent Fresnel lens surfaces 4, 4 in the Y direction, and inclined relative to the XY plane; and a second diffusion surface 16 connecting the lower edge 4b ​​of another second Fresnel lens surface 4 to the first diffusion surface 14.