Epidiascope

epidiascope

[‚ep·ə′dī·ə‚skōp]

(optics)

An optical projection system for forming an enlarged real image of a flat opaque object, in which light is reflected from the object and then from a mirror before being focused by a projection lens. Also known as episcope.

An optical projection system which can easily be altered to project either transparent or opaque objects.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Epidiascope

 

a device for forming an image of an opaque object on a screen as well as for projecting a transparent image, or diapositive, of an object onto a screen. An epidiascope is a projector whose optical system consists of a combination of an episcope and a diascope (see Figure 1).

In diascopic projection, the diapositive is illuminated by a light beam directed through it; thus, the image formed on the screen is sufficiently bright even with a weak light source and projection lenses with low transmission characteristics. Episcopic projection requires the use of light sources that are more powerful and high-transmission lenses.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.