The fresnel lens is a thin sheet made of plastic material. One side of the lens surface is smooth, and the other side is molded with concentric circles from small to large. Its grooves is designed from the interference of light, the relative sensitivity, and receiving angle requirements.
Compared to the conventional spherical lens, a Fresnel lens by the lens divided into a series of concentric circles theoretically infinite number of lines (i.e., the Fresnel zone) to achieve the same optical effect, while saving the amount of material For these lines, the overall thickness of the lens is reduced; ordinary Fresnel convex lens is actually a continuous curved surface is truncated to a section of a discontinuous change of the curvature as the surface is finely divided, so look like a
circle around the lines. Fresnel lenses may in fact be regarded as a series of prisms are arranged in a ring, wherein the relatively sharp edge, and the center of the convex surface is relatively smooth.
Fresnel lenses are mainly used in optical imaging industry ( projectors, VR, AR, etc.), Fresnel lenses are used in LED lighting distribution (spotlights, floodlights, stage lights, traffic signal lights), infrared induction lenses are used in ( industry 4.0 intelligent fields, building security systems, induction lighting, etc.), large Fresnel lenses are used in ( photovoltaic concentrated light generation, heat collection, light utilization, etc.).