Knight Optical (UK) Ltd Fresnel Lens Precision Range 4mm F.L. x 20mmdia aperture LFQ0420

Please note; Due to the size of some of these lenses, we may need charge an additional fee for shipping. If you would like further details, please send your request to customerservices@kni ghtoptical.co.uk 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. 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. Typically, this standard range of lenses are used to emit parallel light from the grooved side where the light source is placed at the focal length position from the plane surface. These lenses can also be used in reverse configuration to converge collimated light, incident from the plane surface, to the focal point from the grooved surface. However, this application may experience some inteference from the draft surface of each groove, so we would recommend our range of specially adapted Reverse Configuration Fresnel Lenses for this. We stock fresnel lenses from 5mm to 650mm aperture, which contains both standard and precision ranges of fresnel lenses. The precision range has tighter tolerances with improved surface quality. These ranges are uncoated, however, antireflective coatings can be applied at short notice. Please note that due to the small size of the fresnel lens on part LFG0505 each 15x15mm part is etched with three 5mm lenses by default.