2 Feb
1999
2 Feb
'99
10:36 a.m.
On Tue, 2 Feb 1999 18:44:35 +0000 (GMT) ard(a)p850ug1.demon.co.uk (Tony
Duell) writes:
Even
Actually, I saw a prototype laserdisk player in a museum somewhere
(I think it was in the LA Museum of Science , but it was a long time
ago) that had the following arrangement: The HeNe laser tube was
bolted down, along with some optics, and a spinning platter/servo motor
mounted on a carriage. The *PLATTER* moved during seeks! It was
really quite bizarre to watch.
They used a *BIG* servo motor to move the carriage, if memory serves.
Jeff
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Tony Duell wrote:
> A photomultiplier isn't that bad to use. OK, it needs a kilovolt
or so of
> EHT. But apart from that it's a fairly
easy device to connect up
and get
> a useable signal from. There should be a lot
of them still about,
and
small
ones aren't that expensive second-hand.
The tricky part is how to mate this with the mechanical assembly. the laserdisc players that used a HeNe laser
still used a
semiconductor
photodetector that was directly mounted on the
sled.
I assume the HeNe tube didn't move with the sled, right (far to much
mass, the servo would never lock). Couldn't you do something similar
with
the photomultiplier - mount it on the chassis and somehow direct the
light beam onto it?