1. An optical projector that can display both transparent slides and opaque objects by reflecting light onto a screen.
Usage: Educational and technical equipment; Largely superseded by digital projectors

Examples

• The teacher used an epidiascope to project pages from the textbook onto the classroom wall.
• Before digital projectors became common, schools relied on epidiascopes for visual presentations.
• The epidiascope allowed the instructor to display both photographic slides and printed documents.
• Museums sometimes used epidiascopes to enlarge and project artifacts for educational displays.
• The epidiascope combined the functions of a slide projector and an opaque projector in one device.