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Scophony System
The English Scophony system is probably the most interesting and
the least known of the scanning methods described here. In spite
of the fact that without a doubt, the Scophony systems provided
the highest performance ever achieved with mechanical scanners.
In 1938, Scophony showed and successfully demonstrated three
types of 405 line mechanical television receivers at the annual
other two were of similar construction, but without cabinets,
were installed and operating successfully. None of these receivers
were sold because their production was halted due to the
oncoming war in Europe.

The Scophony system consisted of several unique innovative
synchronous motors to drive the scanners. Each were important
fundamental Scophony inventions, developed by them for their
mechanical scanning systems.
The Jeffree cell was the light modulator used in the Scophony
improvement over the Kerr cell, both in efficiency and ease of
image elements. Its principle of operation was that if a supersonic
mechanical oscillation passes through a transparent fluid in which
series of retardations and accelerations of the light beam will
occur. These oscillations in the fluid, properly controlled act much
like a diffraction grating and will cause selective cancellations of
the light waves passing through the fluid. By matching the speed
scanning beam passing through the cell, the wave front could act
higher levels of modulated light being passed on to the scanning
mirrors. Optical devices using the same principle of operation as
applications in television and lasers. This was a device well ahead
of its time.
The Scophony system used two mirror drums one as a low
speed scanner with 12 mirrors operating at approximately
240 RPM. A high speed scanner with 20 mirrored surfaces
for the American 441 line system, the high speed scanner
turned at 39,690 RPM. The high speed motors proved good
for at least 1000 hours of use and most went many times
longer with no measurable wear. Considering that the year
was 1938, this was an outstanding accomplishment. At the
same time, Scophony was developing synchronous motors
that could operate at 150,000 RPM.
the novelty of television. These years were also the "coming of age" for mechanical systems During the earlier
years, mechanical television offered many advantages over cathode ray systems and innovation was the rule.
better reliability. There was no popular resistance to mechanical systems as there might today and some
receivers were being sold. As result, there was an ongoing effort on the part of many companies to improve
existing equipment and develop new ideas. World War II completely ended the activity in mechanical television
RADAR! Radar needed to have the same cathode ray tubes, only bigger and better in many ways. The same
circuits only faster, more responsive. By the end of the war, there had been so much progress in radar
development; much of which could be transferred directly back to television, so that the first commercial
sized images.

"DVD Players." Most of us have at least one. I have three, one of which (a Panasonic) is 20years old and has
never required service of any sort. And it is still used occassionally. That says much about the concern for
reliability on mechanical systems.

A recent development is the "DLP", digital light processor, consisting of approximately a million light reflecting
mirrors, in a space the size of your thumbnail. This is an integrated circuit sort of device developed by Texas
Instruments, where the mirrors actually physically move under the control of a video signal. It's an amazing
device and can be found in many of the new "High Definition" sets seen in the stores today.

Peter F. Yanczer