Fresnel lens element

plasticvisibleaspherical

A Fresnel lens is used instead of the curved surface of a traditional lens, it also incorporates a series of concentric grooves which have been molded into the surface of a thin and light sheet of plastic. Each of these grooves is an individual refracting surface and looks like a tiny prism when displayed in cross section. It bends the parallel rays in a quite close approximation to a common focal length. As the lens is quite thin, very small amount of light is lost because of absorption. The Fresnel lenses are a good mixture of efficiency as well as image quality. The high amount of groove density enables good quality of images while lesser grooves result in efficiency (as needed in light gathering applications). In the systems infinite conjugates, the grooved side of the lens must face the longer conjugate. Fresnel lenses are ideally used in light gathering applications like condenser systems or emitter/detector setups. They can also serve as magnifiers or projection lenses; however, due to the high level of distortion, this is . . .