Free Translator Free Translator
Translators Dictionaries Courses Other
Home
English Dictionary      examples: 'day', 'get rid of', 'New York Bay'




Fresnel lens   Listen
noun
Fresnel lens  n.  (Optics) See under Lens.



Lens  n.  (pl. lenses)  (Opt.) A piece of glass, or other transparent substance, ground with two opposite regular surfaces, either both curved, or one curved and the other plane, and commonly used, either singly or combined, in optical instruments, for changing the direction of rays of light, and thus magnifying objects, or otherwise modifying vision. In practice, the curved surfaces are usually spherical, though rarely cylindrical, or of some other figure. Lenses Note: Of spherical lenses, there are six varieties, as shown in section in the figures herewith given: viz., a plano-concave; b double-concave; c plano-convex; d double-convex; e converging concavo-convex, or converging meniscus; f diverging concavo-convex, or diverging meniscus.
Crossed lens (Opt.), a double-convex lens with one radius equal to six times the other.
Crystalline lens. (Anat.) See Eye.
Fresnel lens (Opt.), a compound lens formed by placing around a central convex lens rings of glass so curved as to have the same focus; used, especially in lighthouses, for concentrating light in a particular direction; so called from the inventor.
Multiplying lens or Multiplying glass (Opt.), a lens one side of which is plane and the other convex, but made up of a number of plane faces inclined to one another, each of which presents a separate image of the object viewed through it, so that the object is, as it were, multiplied.
Polyzonal lens. See Polyzonal.






Collaborative International Dictionary of English 0.48








Advanced search
     Find words:
Starting with
Ending with
Containing
Matching a pattern  

Synonyms
Antonyms
Quotes
Words linked to  

only single words



Share |





"Fresnel lens" Quotes from Famous Books



... interior of the lantern, brings to a uniform pressure the inclosed gas, whose pressure continues diminishing as a consequence of the consumption. The lantern is protected against wind and waves by very thick convex glasses set into metallic cross-bars, c. The flame is located in the focus of a Fresnel lens, b, consisting of superposed prismatic rings, and adjusted at its lower part with a circle, d, while a conical ring, e makes a joint at its other extremity. This ring is held by the top piece of the lantern through ...
— Scientific American Supplement, No. 324, March 18, 1882 • Various



Copyright © 2025 Free-Translator.com