Date: Mon, 7 Feb 2011 06:51:57 -

Author: ---

Subject: Re: my projector screen destroys circular polarization

Post:

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A change in the polarization by the reflection from the screen and the paint
surfaces?

No change in polarization by reflection from the black board, the original
polarization is preserved.

Some initial thoughts early Monday morn after cup-o-joe. - J

On Mon, Feb 7, 2011 at 5:02 AM, William Beaty wrote:

> On Sun, 6 Feb 2011, Paul Nord wrote:
>
> When you hold an object (buckeyball model) in the path, you get a pair of
>> shadows cast on the far wall. If you wear REAL-D glasses each eye only sees
>> one of the shadows. And you will see a 3-D image from the shadows.
>>
>
> Back in the old days, if you wanted to do a 3D stereo slideshow with two
> projectors and polarizers, either you had to buy an expensive
> polarization-preserving metallized screen, or you could use brushed sheet
> metal or the matte side of aluminum foil. I think "rear projection" type
> screens also might have worked too.
>
> I suspect that the problem comes from multiple scatterings. Wouldn't
> incoming light remain polarized if it was reflected from just one surface,
> rather than bouncing around inside transparent particles inside "white"
> paint?
>
>
> (((((((((((((((((( ( ( ( ( (O) ) ) ) ) )))))))))))))))))))
> William J. Beaty http://staff.washington.edu/wbeaty/
> beaty, chem washington edu Research Engineer
> billb, amasci com UW Chem Dept, Bagley Hall RM74
> 206-543-6195 Box 351700, Seattle, WA 98195-1700
>



--
Gerald Zani
Demonstration Manager
Physics
Brown University
(401) 863-3964

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A change in the polarization by the reflection from the screen and the pain=
t surfaces?No change in polarization by reflection from the black b=
oard, the original polarization is preserved.Some initial thoughts =
early Monday morn after cup-o-joe.=A0 - J

On Mon, Feb 7, 2011 at 5:02 AM, William Beat=
y m> wrote:

On Sun, 6 Feb 2011, Paul Nord wrote:


When you hold an object (buckeyball model) in the path, you get a pair of s=
hadows cast on the far wall. =A0If you wear REAL-D glasses each eye only se=
es one of the shadows. =A0And you will see a 3-D image from the shadows.




Back in the old days, if you wanted to do a 3D stereo slideshow with two pr=
ojectors and polarizers, either you had to buy an expensive polarization-pr=
eserving metallized screen, or you could use brushed sheet metal or the mat=
te side of aluminum foil. =A0I think "rear projection" type scree=
ns also might have worked too.



I suspect that the problem comes from multiple scatterings. =A0Wouldn't=
incoming light remain polarized if it was reflected from just one surface,=
rather than bouncing around inside transparent particles inside "whit=
e" paint?




(((((((((((((((((( ( ( =A0( =A0 ( =A0 =A0(O) =A0 =A0) =A0 ) =A0) ) ))))))))=
)))))))))))
William J. Beaty =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0http://staff.washington.edu/wbeaty/<=
/a>
beaty, chem washington edu =A0 =A0 =A0Research Engineer
billb, amasci com =A0 =A0 =A0 =A0 =A0 =A0 =A0 UW Chem Dept, =A0Bagley Hall =
RM74
206-543-6195 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Box 351700, Seattle, WA=
98195-1700
-- Gerald ZaniDemonstr=
ation ManagerPhysicsBrown University(401) 863-3964

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