stepped lens

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• Luneburg lens — Cross section of the standard Luneburg lens, with blue shading proportional to the refractive index A Luneburg lens (originally Lüneburg lens, often incorrectly spelt Luneberg lens …   Wikipedia

• 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 — a thin lens made up of a number of stepped setbacks concentrically arranged; it has the optical properties of a much thicker lens …   Medical dictionary

• Fresnel lantern — plano convex lens of equivalent powerA Fresnel lantern (or merely Fresnel) is a spotlight used in theatre, which employs a Fresnel lens to wash light over an area of the stage. The lens produces a wider, soft edged beam of light, which is… …   Wikipedia

• Business and Industry Review — ▪ 1999 Introduction Overview        Annual Average Rates of Growth of Manufacturing Output, 1980 97, Table Pattern of Output, 1994 97, Table Index Numbers of Production, Employment, and Productivity in Manufacturing Industries, Table (For Annual… …   Universalium

• literature — /lit euhr euh cheuhr, choor , li treuh /, n. 1. writings in which expression and form, in connection with ideas of permanent and universal interest, are characteristic or essential features, as poetry, novels, history, biography, and essays. 2.… …   Universalium

• Nonimaging optics — (also called anidolic optics)[1][2] is the branch of optics concerned with the optimal transfer of light radiation between a source and a target. Unlike traditional imaging optics, the techniques involved do not attempt to form an image of the… …   Wikipedia

• Sand Island Light — Infobox Lighthouse caption = Sand Island lighthouse 1962 location = Sand Island, Alabama coordinates = coord|30.1966|N|88.0534|W yearbuilt = 1838 yearlit = 1873 automated = 1921 yeardeactivated = 1933 foundation = Stone construction = Brownstone… …   Wikipedia

• United States — a republic in the N Western Hemisphere comprising 48 conterminous states, the District of Columbia, and Alaska in North America, and Hawaii in the N Pacific. 267,954,767; conterminous United States, 3,022,387 sq. mi. (7,827,982 sq. km); with… …   Universalium

• Stage lighting instrument — Stage lighting instruments are used in stage lighting to illuminate theatrical productions, rock concerts and other performances taking place in live performance venues. They are also used to light television studios and sound stages.Terminology… …   Wikipedia

• Source Four — The ETC (Electronic Theatre Controls) Source Four (also known unofficially as Source 4 or S4 ) is an ellipsoidal reflector spotlight, a type of spotlight used in stage lighting. The ETC Source Four revolutionized stage lighting in 1992 cite news… …   Wikipedia