Definitions for "Fresnel lens"
See under Lens.
a very thin lens designed to be equivalent to a much thicker lens made the conventional way (see figure 23.14)
Optical lens named after its inventor Augustin-Jean Fresnel. Originally developed for light houses, since it allows the construction of huge lenses with low focal distance. Today it is used in overhead projectors and rear projection tvs.
a ribbed circular surface, which enlarges objects behind it