AY Honors/Optics/Answer Key

2007-02-06T00:12:45Z

151.76.132.104: interlinks de:Episkop and pl:Episkop

The '''opaque projector''', '''epidioscope''', '''epidiascope''' or '''episcope''' is a predecessor to the [[overhead projector]]. It displays opaque materials by shining a bright lamp, often [[limelight]], onto the object from above. A system of mirrors, prisms and/or imaging [[Lens (optics)|lenses]] is used to focus an image of the material onto a viewing screen. Because they must project the reflected light, opaque projectors require brighter bulbs and larger lenses than overhead projectors. Care must be taken that the materials are not damaged by the heat generated by the light source. Opaque projectors are not as common as the modern "overhead".

Opaque projectors are typically used to project images of book pages, drawings, mineral specimens, leaves, etc. They have been produced and marketed as artists’ enlargement tools to allow images to be transferred to surfaces such as prepared canvas, or for lectures and discourses. In the early and middle parts of the 20th century, low-cost opaque projectors were produced and marketed as toys for children.

==See also==
* [[Projector]] for a directory of projector types.

==External links==

* [http://www.luikerwaal.com/newframe_uk.htm?/epidia_uk.htm Episcopes and epidiascopes], photographs of a collection.
* [http://www.curzon.org.uk/collection/Epidiascope.html Historic Ross Epidiascope]
* [http://adverlab.blogspot.com/2005/03/tools-epidiascope.html Brief description] of the modern [[Braun]] Paxiscope XL Epidiascope.
* [http://www.firstcall-photographic.co.uk/pp/Projectors/35mm_Projectors_and_Epidiascopes/Braun_Paxiscope_XL_Epidiascope.html Another description] of the Braun Paxiscope unit.
* [http://adverlab.blogspot.com/2005/06/epidiascope-strikes-back.html Digital epidiascope] from [[Samsung]].

[[Category:Projectors]]

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AY Honors/Optics/Answer Key