Eidophor

[3] An original August 1952 magazine article in the Radio and Television News[4] credits the development of the Eidophor to Edgar Gretener.

[8] Over 100 cinemas were set up for the project, which failed because of financial losses and the refusal of the U.S. Federal Communications Commission (FCC) to grant theatre owners their own UHF radio bands for presentation.

Eidophors used an optical system somewhat similar to a conventional movie projector, but substituted a slowly rotating mirrored disk or dish for the film.

Light was shined on the disc by a striped mirror consisting of strips of reflective material alternating with transparent non-reflective areas.

As the disk rotated, a doctor blade discharged and smoothed the ripples in the oil, readying it for re-use on another television frame.

An early prototype of a new type of projector with limited resolution using a passive matrix-addressed liquid-crystal display was shown at a conference in San Francisco by Swiss engineer Peter J.

Current technologies include liquid-crystal display (LCD) and digital light processing (DLP) projectors, both of which produce superior results from easily portable devices.