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Article #6261What is a Fresnel lens? -- was Re: That Magic TV screen
From: Michael A. Covington
Date: Tue, 25 Aug 1992 17:27
Date: Tue, 25 Aug 1992 17:27
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Two different devices are called a Fresnel lens: (1) A device that works by diffraction, and is seen mainly in optics textbooks. This device is very wavelength-specific. (2) A collapsed convex lens, in concentric zones. This is what "magnifying sheets" are made of, and is also found in projectors and spotlights. It is wavelength-sensitive only to the extent of the chromatic dispersion of the glass. -- + Michael Covington - Artificial Intelligence Programs - U of Georgia - USA + Unless otherwise noted, these are private opinions, not official statements. + VOTE NO GEORGIA LOTTERY - don't tie education to an unpredictable income.
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Path: arc1-ca.pugleaf.net!sparky!uunet!ogicse!emory!athena.cs.uga.edu!mcovingt From: mcovingt@athena.cs.uga.edu (Michael A. Covington) Newsgroups: sci.electronics Subject: What is a Fresnel lens? -- was Re: That Magic TV screen Message-ID: <1992Aug25.172720.7172@athena.cs.uga.edu> Date: 25 Aug 92 17:27:20 GMT Article-I.D.: athena.1992Aug25.172720.7172 References: <1992Aug23.175543.18596@usenet.ins.cwru.edu> <76160028@hpldsla.sid.hp.com> Organization: University of Georgia, Athens Lines: 14