Eidophor
An Eidophor was a
Origins and use
The idea for the original Eidophor was conceived in 1939 in
Following the Second World War, a first demonstration of an Eidophor system as a cinema video projector was organized in the Cinema Theater REX in Zürich to show successfully a TV broadcast in April 1958.[2] An even more promising perspective was the interest of
]Eidophors used an optical system somewhat similar to a conventional movie projector, but substituted a slowly rotating mirrored disk or dish for the film. The disk was covered with a thin film of transparent high-viscosity oil, and through the use of a scanned electron beam, electrostatic charges could be deposited onto the oil, causing its surface to deform. Light was shined on the disc by a striped mirror consisting of strips of reflective material alternating with transparent non-reflective areas. Areas of the oil unaffected by the electron beam would allow the light to be reflected directly back to the mirror and towards the light source, whereas light passing through deformed areas would be displaced and would pass through the adjacent transparent areas and onwards through the projection system. As the disk rotated, a doctor blade discharged and smoothed the ripples in the oil, readying it for re-use on another television frame.[10]
![](http://upload.wikimedia.org/wikipedia/commons/thumb/0/0a/Eidophor_display_Mission_Control_Center_Houston.jpg/220px-Eidophor_display_Mission_Control_Center_Houston.jpg)
The Eidophor was a large and cumbersome device. It required a setup crew of at least two engineers and three-phase AC power service. Often, contamination of the oil bath would cause visible artifacts to appear in the projected image. A rainbow-effect "eyebrow", or halo, surrounded the projected image.
It was not commonly used until there was a need for good-quality large-screen projection. This opportunity arose as part of the NASA space program, where the technology was deployed in mission control.
Eidophors were also used in stadiums by touring music groups for
Simple Eidophors produced black-and-white images. Later units used a color wheel (equivalent to the color television standard CBS tried to bring to the market against RCA/NBC's FCC-approved NTSC system, and today's DLP projection system) to produce red, green, and blue fields. The last models produced used separate red, green, and blue units in a single case. The Eidophor was 80 times brighter than CRT projectors of the time. The last Eidophors were able to project colour images of up to 18 metres in width.
Advances in
See also
Notes
- ^ Winston, Brian, Media Technology and Society, 1998 Routledge, p. 23.
- ^ a b Monika Burri: Der Eidophor-Projektor. ETH History 1855 - 2005. Retrieved 26 September 2019
- ^ ISBN 978-3-03823-791-4
- ^ "Eidophor Projection System".
- ^ "19480710 Boxoffice / July 10, 1948". issuu.com. Archived from the original on 2009-11-05.
- ^ "Cinema-television".
- ^ Ilias Chrissochoidis (ed.), Spyros P. Skouras, Memoirs (1893–1953) (Stanford, 2013), pp. 149–150.
- ^ Gomery, Douglas, Shared Pleasures: A History of Movie Presentation in the United States, 1992 University of Wisconsin Press, p. 233.
- ^ Winston, Brian, Misunderstanding Media, 1986 Taylor & Francis, p. 81.
- ^ Baumann, Erns (1961t). Der Eidophor: Eine Schweizerische Entwicklung der Fernseh-Grossprojektion [The Eidophor: A Swiss Development of Large-scale Television Projection] (PDF) (Neujahrsblatt [annual bulletin]) (in German). Zurich: Gebr. Fretz AG, for Naturforschende Gesellschaft in Zürich. Retrieved 26 September 2019.
- ^ Wild, Peter J. (June 1972). "Matrix-addressed Liquid Crystal Projection Display". Digest of Technical Papers, International Symposium, Society for Information Display: 62–63.
References
- Robertson, A. (1976) Projection Techniques:TV, pp. 149–150, in Video Year Book 1977, Poole, The Dolphin Press.
- Johannes, Heinrich (1989) The History of the EIDOPHOR Large-Screen Television Projector, GRETAG AG, Regensdorf, Switzerland
- Meyer, Caroline (2009) Der Eidophor: Ein Grossbildprojektionssystem zwischen Kino und Fernsehen 1939–1999. (Interferenzen – Studien zur Kulturgeschichte der Technik, 15). Chronos-Verlag, Zürich 2009, ISBN 978-3-0340-0988-1.
External links
- The history and workings of Eidophor projection
- August, 1952 issue of Radio & Television Newsmagazine article discussing Eidophors
- Eidophor: 1950's Steampunk Video Projection Technology, presentation by Mike Harrison at the 2016 Hackaday Belgrade conference
- Make It Better Than Just Being There, 1992 Eidophor promotional film, hosted by the Museum for Communication