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- Path: 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
-
- 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.
-