[AG-TECH] rear projection display

S.Booth spb at epcc.ed.ac.uk
Mon Dec 8 04:02:46 CST 2003

On Fri, 5 Dec 2003, Robert Callaway wrote:

> I'm currently in the planning stages for an Access Grid at the 
> University of California, Santa Barbara. I really like the idea of using 
> a rear projection system for the room, but space is limited. I have 
> looked into different options, such as using mirrors or short throw 
> lenses to decrease the distance needed. I'm curious if anyone could 
> offer any specific recommendations on rear projection equipment that 
> they have been happy with (ie. projectors, screens, and lenses). I am  
> particularly interested if  anyone has  information  on a projection 
> system  with  a  short  throw lens that is economical (under $5000).
We use back projection and have another AG coming on stream that also 
uses back projection.
We use Epson EMP-810 There should be better models available now.
In our node we just place conventional projectors on a shelf in the back
projection room. In the new room the projectors are on fixed mounts that 
make lining them up easier. Choice of mount is important. because your
projectors are locked away in a back room and you have more freedom in the
mounts you use it is possible to get a very good alignment of the
projectors, good enough to not have to worry about windows that cross from
one projector image to anouther. However this requires very precise
alignment. With our shelf mounted projectors I have to do fine adjustment
using sheets of paper under the projector feet :-) 

We actually built our projection room deeper than we had to because we
could only source a screen of a certain height and the projectors had a
shorter throw than the one we originally planned to use.

Note that with back project you can sit much closer to the screen than
with ceiling projectors so a smaller closer screen can give the same image
size from the audience, this reduces the length of throw needed. However
this only holds for meeting room installations rather than large
lecture theatres.


|epcc| Dr Stephen P Booth             Project Manager           |epcc|
|epcc| s.booth at epcc.ed.ac.uk          Phone 0131 650 5746       |epcc|

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