Freddy Basset
01-04-2006, 10:34 AM
Rare and obscure CRT, D-ILA and DLP precursors and museum pieces:
In 1940, RCA installed electronic projectors in a movie theater in NYC:
http://www.earlytelevision.org/rca_theater.html
Check out the schematic with the variacs in the control panel.
=====================================
Time line:
First RCA rear-projector was introduced in 1946:
http://www.sid.org/archives/0%20-%20Projection%20pdf%20Exhibit%204.pdf
=============================================
"Eidophor" projectors from Switzerland used a thin layer of transparent oil on an aluminum
mirror, reportedly _still_ have stunning images. On some, the frame was
refreshed by scraping the oil surface smooth.
"If the size of the spot on the oil is adjusted such that adjacent lines
just begin to overlap, the charge is distributed uniformly over the whole
area, the pressure on the oil is uniform, and no deformations are generated.
If the size of the electron spot is narrowed, the charge distribution is no
longer uniform, but reflects the TV line pattern, as does the resulting oil
layer deformation. The smaller the spot, the deeper will be the
deformation."
http://www.spgv.com/columns/eidophor.html
===================================
"The 1954 edition of "Basic Television" (Bernard Grob)
mention several types of projection TV, including
5TP4-based (with some detail), Eidophor and Scophony
(with no detail on the latter two).
It even claims there was a system based on kinescoping
a TV monitor at the theater, filming that, developing and
drying the film, and projecting it, all as a continuous process.
I wonder if today's 35mm theatres will get converted to
digital, or if theatrical exhibition will implode first.
--
Regards, Bob Niland"
Webpage on Scophony:
http://www.tvhistory.tv/1938-Scophony-UK.htm
Talk about a spinning color wheel . . . fascinating. :wow:
============================================
Japanese Muse HDTV was demonstated here in the USA in the early 1990's
using three-piece General Electric "Talaria". It weighed 600 lbs, used 50
amps @ 234 Volt, needed 20 minimum warm-up time and had horrendous
maintenance issues.
http://www.hi-def.com/3LV.html
"In the Talaria, the oil film is made by rotating a glass disc, with a
conductive surface, which dips into an oil bath and picks up its coating.
Like the Eidophor, when no charge is projected onto the oil film by the
electron gun, all light is blocked by the Schlieren stop. In this case the
green component is blocked by horizontal bars and the magenta component by
vertical bars. When the image is projected via the electron beam onto the
oil film, it deforms and reflects light past the Schlieren stop into the
lens".
These types are still found on ebay now and then, I'd love to get one and
play with it.
I think that was the design that led to the CRT-addressed ILA panels made by
Hughes, then becoming JVC-Hughes, and now pushed further along by Sony with
the SXRD/LCOS "Ruby" projector. [VPL-VW100. ~$8,500, street].
An amazing unit and yes, I want one. :overclap:
[posting copied over from Usenet]
In 1940, RCA installed electronic projectors in a movie theater in NYC:
http://www.earlytelevision.org/rca_theater.html
Check out the schematic with the variacs in the control panel.
=====================================
Time line:
First RCA rear-projector was introduced in 1946:
http://www.sid.org/archives/0%20-%20Projection%20pdf%20Exhibit%204.pdf
=============================================
"Eidophor" projectors from Switzerland used a thin layer of transparent oil on an aluminum
mirror, reportedly _still_ have stunning images. On some, the frame was
refreshed by scraping the oil surface smooth.
"If the size of the spot on the oil is adjusted such that adjacent lines
just begin to overlap, the charge is distributed uniformly over the whole
area, the pressure on the oil is uniform, and no deformations are generated.
If the size of the electron spot is narrowed, the charge distribution is no
longer uniform, but reflects the TV line pattern, as does the resulting oil
layer deformation. The smaller the spot, the deeper will be the
deformation."
http://www.spgv.com/columns/eidophor.html
===================================
"The 1954 edition of "Basic Television" (Bernard Grob)
mention several types of projection TV, including
5TP4-based (with some detail), Eidophor and Scophony
(with no detail on the latter two).
It even claims there was a system based on kinescoping
a TV monitor at the theater, filming that, developing and
drying the film, and projecting it, all as a continuous process.
I wonder if today's 35mm theatres will get converted to
digital, or if theatrical exhibition will implode first.
--
Regards, Bob Niland"
Webpage on Scophony:
http://www.tvhistory.tv/1938-Scophony-UK.htm
Talk about a spinning color wheel . . . fascinating. :wow:
============================================
Japanese Muse HDTV was demonstated here in the USA in the early 1990's
using three-piece General Electric "Talaria". It weighed 600 lbs, used 50
amps @ 234 Volt, needed 20 minimum warm-up time and had horrendous
maintenance issues.
http://www.hi-def.com/3LV.html
"In the Talaria, the oil film is made by rotating a glass disc, with a
conductive surface, which dips into an oil bath and picks up its coating.
Like the Eidophor, when no charge is projected onto the oil film by the
electron gun, all light is blocked by the Schlieren stop. In this case the
green component is blocked by horizontal bars and the magenta component by
vertical bars. When the image is projected via the electron beam onto the
oil film, it deforms and reflects light past the Schlieren stop into the
lens".
These types are still found on ebay now and then, I'd love to get one and
play with it.
I think that was the design that led to the CRT-addressed ILA panels made by
Hughes, then becoming JVC-Hughes, and now pushed further along by Sony with
the SXRD/LCOS "Ruby" projector. [VPL-VW100. ~$8,500, street].
An amazing unit and yes, I want one. :overclap:
[posting copied over from Usenet]
