| Dictionary, Encyclopedia and Thesaurus - The Free Dictionary 1,506,462,164 visitors served. |
|
Dictionary/ thesaurus | Medical dictionary | Legal dictionary | Financial dictionary | Acronyms | Idioms | Encyclopedia | Wikipedia encyclopedia | ? |
Fresnel lens |
Also found in: Dictionary/thesaurus, Wikipedia | 0.03 sec. |
Fresnel lensSeries of concentric rings, each consisting of a thin part of a simple lens, assembled on a flat surface. G.-L.-L. Buffon (1748) first had the idea of dividing a lens surface into concentric rings to reduce the weight. In 1820 his idea was adopted by Augustin-Jean Fresnel (1788–1827) for the construction of lighthouse lenses. Fresnel lenses have the optical properties of much thicker and heavier lenses. They are used in spotlights, floodlights, railroad and traffic signals, and decorative lights. Some thin Fresnel lenses are molded in plastic, the width of the rings being only a few thousandths of an inch; such lenses are used in cameras and small projectors. How to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit webmaster's page for free fun content. |
|
| ? Mentioned in | ? References in periodicals archive | |
|---|---|---|
engineers check out a component of the Improved Fresnel Lens Optical Landing System, designed and developed by NAVAIR Lakehurst. Whereas an ordinary lens must become thicker as it gets larger to accumulate a phase shift of many times 2[pi], a Fresnel lens has a maximum thickness. A museum on the island houses the original crystal and brass Fresnel lens from the lighthouse. |
| Encyclopedia |
| Free Tools: |
For surfers:
Browser extension |
Word of the Day |
Help
For webmasters: Free content | Linking | Lookup box | Double-click lookup | Partner with us |
|---|