Epidiascope


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Related to Epidiascope: magic lantern

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.

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.

References in periodicals archive ?
"The epidiascope contrasts with the television suite used by our media and journalism students."
Because they must project the reflected light epidiascopes need brighter bulbs and larger lenses than overhead projectors
Epidiascopes have been used as artists' enlargement tools, to allow images to be transferred to surfaces such as prepared canvas, or for lectures and talks.