Fresnel lens

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Fresnel lens
Lens Lens (l[e^]nz), n.; pl. {Lenses} (-[e^]z). [L. lens a lentil. So named from the resemblance in shape of a double convex lens to the seed of a lentil. Cf. {Lentil}.] (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. [1913 Webster] Lenses [1913 Webster]

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. [1913 Webster]

{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}. [1913 Webster]

The Collaborative International Dictionary of English. 2000.

Look at other dictionaries:

• Fresnel lens — Fres nel lens [See {Fresnel lamp}.] (Optics) See under {Lens}. [1913 Webster] …   The Collaborative International Dictionary of English

• Fresnel lens — n. [after FRESNEL Augustin Jean] a thin optical lens of many concentric rings, having the properties of a much thicker and heavier lens: used in cameras, lighthouse beacons, etc …   English World dictionary

• Fresnel lens — A Fresnel lens (pronounced [ frɛz.nəl] or [freɪ nɛl] ) is a type of lens invented by French physicist Augustin Jean Fresnel. Originally developed for lighthouses, the design enables the construction of lenses of large aperture and short focal… …   Wikipedia

• Fresnel lens — Optics. a large lens with a surface of concentric grooves of prismatic profile, used in automobile headlights, searchlights, spotlights, etc. [1840 50; see FRESNEL] * * * Series of concentric rings, each consisting of a thin part of a simple lens …   Universalium

• Fresnel lens — noun lens composed of a number of small lenses arranged to make a lightweight lens of large diameter and short focal length • Hypernyms: ↑lens, ↑lense, ↑lens system • Part Holonyms: ↑headlight, ↑headlamp, ↑searchlight * * * …   Useful english dictionary

• Fresnel lens — noun Etymology: Augustin J. Fresnel Date: 1865 a lens that has a surface consisting of a concentric series of simple lens sections so that a thin lens with a short focal length and large diameter is possible and that is used especially for… …   New Collegiate Dictionary

• Fresnel lens — Fres·nel lens (fra nelґ) [Augustin Jean Fresnel, French physicist and engineer, 1788â€“1827] see under lens …   Medical dictionary

• Fresnel lens — /frənɛl ˈlɛns/ (say fruhnel lens) noun a large lens with a short focal length, used in headlights, spotlights, etc. {See Fresnel diffraction} …   Australian English dictionary

• fresnel lens — [freɪ nɛl] noun Photography a flat lens made of a number of concentric rings, to reduce spherical aberration. Origin C19: named after the French physicist and civil engineer Augustin J. Fresnel …   English new terms dictionary

• fresnel lens — F/A/V a flat glass or acrylic lens in which the curvature of a normal lens surface has been collapsed in such a way that concentric circles are impressed on the lens surface; often used for the condenser lens in overhead projectors, in rear… …   Audio and video glossary