Ok, here's the guts of an all acousto-optic full color laser video
projector I built back in 1986, AO means there were no moving
parts to do the high speed horizontal scan, the only moving part
was a small galvo to do the vertical 60hz scan. There have only
ever been a few of these built, mainly because of cost. Except for
the optical table (black box) I machined and built everything else
on it from scratch.  It did make a couple of public appearences,
the biggest being the 4th of July
in New Orleans down on the
waterfront in front of Jack's Brewery.
We had a 45 by 60 foot
screen built on scaffolding floating on a
a barge in the Mississippi river,
we did a half hour laser show, then
I took a live video feed from the
local TV crew and projected the
fireworks display and crowd reactions
up on the screen. It was
pretty neat until the winds picked up and
we had to drop the
screen before it pulled the barge over onto the
crowd of about

Here's the same projector with the lights off so you can kinda get
an idea of how much the light was manipulated. I was using two
Spectra Physics 171 argon and krypton lasers. There was an
interesting concept applied to this projector. Others like it used
a dye laser for the red line, which in television is actually orange.
That's mainly because there is no such thing as a red phosphor
for television, so other folks went to a lot of trouble to get orange
laser light. I took a different approach. The krypton laser has
a very dark red line as can be seen in the picture. I took a portion
of the RGB video signal, in this case the R signal, and injected
it into the green laser beam, so when the red was on, a fraction of
the green was on as well which gave a fairly good approximation
of the orange video phosphor without having to use the dye laser
which are just nightmares to operate. It kinda seemed like a no
brainer to me to do it that way.

Here I am standing in front of a rear screen with the projector
facing me, so we are actually looking at the back side which is
much dimmer than the high gain front side that an audience would
see. I put this here so if you look at the lower right corner, you can
see me and get some idea of the scale of this. The projector was
about 15 feet away, I did this to prove to a few folks that AO
devices could achieve large scan angles at a close distance. I had
numerous "experts" tell me and my bosses that this coudn't be
done, and that the largest image to expect at this distance would
be about 2 feet square. These images were from a laser disk
player showing one of those Siggraph "best of" samples.
It was full motion video, I used to sit and watch "Top Gun"
and "Brazil" all day long as they were the only two other disks
I had..

Here I am at the control rack for this thing. Other than the test
gear, I built everything else that you see rack mounted as you just
couldn't buy this stuff off the shelf. The large piece of foamcore
was just a mask to try to keep stray light from gettin to the back
side of the RP screen as we we're demo'ing the unit to certain
folks. In a later picture of color bars, you will see a bright spot
in the middle of the screen, I had forgotten to put the foam core
back up, so that ghost image is just light spill from the laser table.
We never even got around to building a cover for it..

Here's the same rack with the lights on so you can get a little idea
of how much electronic work I had to do besides just the optical.

Here are the color bars, not too bad, I needed to do a convergence
on them pretty bad, but I was waiting on a custom ground cyl. lens
to come in before I could do that. Still, the color rendition was
very good. One nice thing was because I had such a deep source
of red and blue, colors that are not normally seen on TV could be
seen on this display. Dark magenta's (Tom Cruise's helmet in Top
Gun) was a good example, on tv it just mushes out, on this system
it just jumped out. Things like browns looked very nice too.
It looked a lot more like film than video.

Well, that was it for the laser video, there's way too much that I could
have put up, I even have some mpeg's of a similiar unit that I built
to go to Italy, but I decided to leave that 14meg file out of here.
    Below was one of my later projects, a holographic mirror construction
system. This was used for making fingerprint scanners. The white angled
glass blocks in the lower left hand corner are where the hologram was made,
and you can just slightly make out the green beam coming from the laser at
the top. Over on the right side is an unusual device called a "fringe Stabilizer"
It would monitor vibration down to within a 1/4 of a wavelenth of light, and
then self cancel out the vibration by changing the beam path with the use
of a mirror on a voice coil. That is what that unit with two cables going to it
is on the right side of the image. Jeff L. has the origins of that unit somewhere,
our nickname for it was "the butt buzzer"... He can explain that one to you.
Ask him about the talking straws while your at it, I promise you will get
a laugh out of that if he still remembers. I also designed and machined all
these mounts, etc. for this lab, which is now sitting all bundled up in my
garage except for the laser and the 5x8 ft air suspension table. It came in
at about 3000lbs, and I was tired of moving it so I sold it off in 99'..

And just to show I have some fun now and then, this is me on the
left in downtown Beirut doing a "reverse" synch'd theater outdoors...
Actually, it was a twin 35mm projector smpte locked system where
the projectors chased time code on a Tascam 8 track reel to reel.
I used Adams Smith Synchronizers to run the projectors, which was
interesting in that I had to convince the AS units that these 500lb
projectors had the response time of a reel to reel tape deck so that
they could chase and lock. But it worked, even though we would
get shot at a couple of times a day from the apartment buildings
that surrounded the soccer field we were set up on. Jeff might
know the British fellow next to me, a Mr. Brian Legge who was
at one time an Electrosonic employee as well. I suspect after having
travelled the mid-east with him that he also moonlighted for UK
Intelligence as he knew too many things for our own good...

Ok, at the request of some folks that wanted to see some of the
Pink Floyd 1986 thru about 88 Tour, I have some OLD and grubby
photo's that came out of one of about 5 shoeboxes full of stuff, I
imagine the negs are in there and would have done better, but I don't
have anything to scan them with, sooooo...

So, here's one of the basic, but massive stage setup, which.. well, was
just huge... This is inside the Houston Astrodome on the last day of
load-in, which took 4 days to build the stage, etc. If you can ever find
the concert tape, it's well worth watching to see all of this stuff at work,
especially all the massive overhead crane lighting "pods" that would just
kinda wander about either at the roof of the truss's or down about 4 ft.
over David's head during a solo. This was from back at the sound riser
which was 4 levels high with the laser level on top. An amazing place
to watch and hear "Comfortably Numb" from as the sound was in
full quad, and beyond loud.. If you could pull yourself off of watching
the show and look back at the audience, the ones that weren't lying
on the floor in spasm's were just standing with their jaws hanging open..

Ok, now for some pics that had been requested of the lasers simulators
used on this and a bunch of other tour's. Most of the gear from this tour
went right back out on the road with the McCartney Tour which started
up just after this one ended. This first pick is hard to tell, but it's four of
the simulators that each had two fiber outs, and were sitting on the
bottom of the Droid lifts, so each Droid moving head had 8 outputs.

There was also a spare and then the controller underneath.

And here's an attempt at a close up of that lamphouse. The two
round things are the two concave reflectors which are in the patents
I believe, and then all the blue jacketed cable is the fiber.
This is
probably one of the only pictures of this unit ever open and lit as
there is an interlock for the PS on the top of the box as there was
a lot of UV, etc. floating around inside.

And, I just had to include this: This is a pic for historical purposes of
the tech in charge of all this, a very young Scott Ritt. I'm sure quite a
few of you might know him. This was just about his first tour I believe,
and he started out very clean cut and baby faced. The system ran off
of a Mac, but could also run off of a Atari MegaST. Also, the picture is
so cruddy and dark as Scott is standing directly under the stage from
where David Gilmore would be standing (the stage was just open grating
in this area), and he had this open "tunnel" to himself that he could move
about to get at all the Droid's. Normally, the Mac and Scott would be
out at the sound riser, but they had pulled the controller back under the
stage to do some work during setup, and then considering it was still 1986,
the whole laser and fiber part of the show was run from out in the FOH
to the stage over regular fiber optic RS232 modems, so with the miles of
cable back to the riser, these guys had it easy as they just had a duplex
fiber bundle to lay out to run the show. If Scott see's this and would like
it removed, please just ask and I will pull it. Well, that's it for the Floyd
stuff, wish the quality was better, I may try and see if I can get some
captures off the concert tape if they look any better, but I doubt it.

    Hope you enjoyed these pics of some old laser history, I'm happy that
I still can remember where I had them at this point in my life... Doug

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