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A Fresnel lens is a type of lens developed by French physicist Augustin-Jean Fresnel for lighthouses; a similar design had previously been proposed by Buffon and Condorcet as a way to make large burning lenses. The design enables the construction of lenses of large aperture and short focal length without the weight and volume of material that would be required in conventional lens design. Compared to earlier lenses, the Fresnel lens is much thinner, thus passing more light and allowing lighthouses to be visible over much longer distances. The use of a Fresnel lens reduces image quality, so they tend to be used only where quality is not critical or where the bulk of a solid lens would be prohibitive. Cheap Fresnel lenses can be stamped or moulded out of transparent plastic and are used in overhead projectors, projection televisions, and hand-held sheet magnifying glasses. Fresnel lenses have been used to increase the visual size of CRT displays in pocket televisions, notably the Sinclair TV80. They are also used in traffic lights. Fresnel lenses are also used to correct several visual disorders, including several ocular motility disorders such as strabismus. Since plastic Fresnel lenses can be made larger than glass lenses, as well as being much cheaper and lighter, they are used to concentrate sunlight for heating in solar cookers, solar forges, and solar collectors to heat water for domestic use. Source for Fresnel Lenses. B2BManufactures.Com incorporates full list of Taiwan- & China-based manufacturers and suppliers. In addition, there are a wide selection of Fresnel Lens presented with highly resolved images as a great help in researching and purchasing.
source: Wikipedia: the free encyclopedia
