Fresnel lens
(rus. линза Френеля otherwise Френелевская линза)
—
a complex compound lens proposed by Fresnel.
Description
The Fresnel lens does not consist of a single polished piece of optical material with spherical or other surfaces like conventional lenses, but instead it is made of a succession of individual, thin concentric rings, which, in cross section, have the special prism shape (see Figure 1).
Initially, Fresnel lenses were used in lighting systems, for example, in the focusing systems of lighthouses for collimation of optical radiation. Also, large Fresnel lenses were used as screens of projection TVs.
In the optical systems of image-forming lenses (Canon EF 70-300mm DO IS f/4.5-5.6) released later, a pair of Fresnel lenses was used for improved aberration correction.
Currently, the most promising applications for Fresnel lenses include solar energy concentrators of solar cells and focusing elements of X-ray microscopes (Fresnel zone plate).
Initially, Fresnel lenses were used in lighting systems, for example, in the focusing systems of lighthouses for collimation of optical radiation. Also, large Fresnel lenses were used as screens of projection TVs.
In the optical systems of image-forming lenses (Canon EF 70-300mm DO IS f/4.5-5.6) released later, a pair of Fresnel lenses was used for improved aberration correction.
Currently, the most promising applications for Fresnel lenses include solar energy concentrators of solar cells and focusing elements of X-ray microscopes (Fresnel zone plate).
Illustrations
Author
- Alexey V. Bratishev