Re: preliminary summary on ghosting

[P3D Gregory J. Wageman <gjw@xxxxxxxxxx>]

Peter Abrahams wrote:

>--the screen used at NSA is a very unusual lenticular screen.  Is it
>possible that this optical element, with very small refracting elements,
>introduces a depolarization?  I imagine the lenticular elements
>(lenticles?) are not hugely larger than the glass beads used on screens.

Actually the material is quite common.  "Da-Lite" (http://www.da-lite.com/)
calls it "Super Wonderlite".  The lenticules do not refract, only reflect.
According to Da-Lite, their purpose is to reflect back towards the
center of the viewing area, some of the light that would have reflected
off to the sides if the screen were completely flat.  This design
trades off useful viewing angle for a brighter image nearer the center,
which happens to be a very useful trade-off for stereo projection.

	-Greg W.


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