Projector-View Screen Info - Maybe

[P3D <BD3D@xxxxxxxxxx>]

Hi.  There has been a string on Tech-3D recently regarding rear-
projection screens that could apply to Projector-View.  Here is the
post I just sent there:



Hi.  Thanks to all who responded to my request re: rear projection
screen material, both on and off list.  The concurrent discussion
about ProjectorView glass on p-3d has helped too.

Da-Lite has a website, http://www.da-lite.com, and they also have
some technical pages, called "Angles of View" available on the net.
One of these, Vol.1 No.4 (http://www.bsg.nl/bsg/techdoc/vol14.html)
is a general comparison of front vs. rear projection, but nothing
specifically about stereo/polarized. It does mention that there's a
free 24-page handbook entitled "Selecting Rear Projection Screens
For Today's Presentation Applications" is designed to help you
decide which of their eleven different models of rear projection
screens you need.

Another "Angles of View" that I found was Vol. 1 No. 8
(http://www.rentcom.com/wpapers/dalite/vol18.html) This one
discusses "folding" the projection path with mirrors to reduce the
space required for rear projection. Again nothing specifically
about stereo.

I called Da-Lite (Phone 219-267-8101. I got their website from the
recorded message playing while I was on hold). Spoke with Wendy.
She is sending samples of Da-Tex, Da-View and Poly-Lens material. I
hadn't seen the reference to their handbook yet and she didn't
mention one, but maybe they'll toss it in the box with the samples.

The Da-Tex was described as a flex fabric material with high
transmissive values and extremely low reflective values. The Da-
View is a 1/4" acrylic lenticular with a diffuser surface. The
Polylens is a three piece sandwich that I think she said was
lent/diff./lent.

I also called Gerriets International in NJ (609-758-9121).  The
tech guy there said that he had been geeting more and more requests
for non-depolarizing material lately and they are investigating,
but nothing now. He says all their screens are acrylic vinyl and
they depolarize.

Dick at Vutec Corp. in FL (954-964-6400) didn't hold high hopes for
success, but he is sending a scrap of their "2 1/2 gain fabric"
rear projection material to let me test.

Jeff at Hudson Photographic in NY (914-591-8700) is sending a
sample of their material.

I hope to be able to rig these samples in some sort of array so's I
can project on all of them at once. When my exhaustive :-) research
is complete, I'll report my findings.

One interesting thing I accidently discovered while testing various
materials was that dirty glass works pretty well for rear-
projection stereo!  Actually, the dirt was quite evenly applied, as
it was the dust that had gathered on some windows that had been
stored in my attic by the previous owner over ten years ago.  By
cleaning one side of the glass and projecting against the other, I
got surprisingly good polarization.  The diffusion factor was low,
though, so straight-on viewing was blinding, but just off to one
side the results were real cool! Of course my aim was to be able to
walk right up to the screen, so technically this discovery doesn't
count. :-)

I'll keep you posted.


Best regards,
Bill Davis


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