Fresnel lenses consist of a flat surface with interspaced, concentric steps whereby each step corresponds to the surface of a conventional lens. Each step thereby acts as a refractive surface, much like a prism. This gives the fresnel lens a common focal length equivalent to a traditional lens, but with a fraction of the thickness. Additionally, because the lens is so thin little light is lost by absorption. Although the image quality is generally poor, fresnel lenses can be desirable for use in condenser and lighting systems to collimate and collect light in equipment such as sensors or communication systems. Fresnel lenses can be used as magnifiers, but this is not recommended unless the thin profile and light weight is absolutely necessary. Fresnel PMMA lenses are also ideal for simulators and projection systems.
This stock range of cylindrical fresnel lenses focus light in one direction rather than focusing to a point. This range of cylindrical fresnel lenses is uncoated however antireflective coatings can be applied at short notice.