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Re: Fresnel lens image



Take a look at the following site for some information
http://www.kodak.com/US/en/motion/dynamic/index.shtml

Dr. Lawrence D. Woolf; General Atomics, 3550 General Atomics Court, San
Diego, CA 92121; Ph: 858-455-447; www.sci-ed-ga.org


Subject: Re: Fresnel lens image


If you can actually grossly feel and see these parallel grooves, then it
cannot possibly be a diffraction effect -- for diffraction effects, you
need parallel grooves that are spaced at least of the order of 1000 per
inch, but the closer the better. What you have is more likely a refraction
effect -- probably a triangular shaped groove in the plastic that lets you
see one image when viewing through one face (side of the goove) and another
image when looking through the other. I imagine the pictures underneath
must be sliced at the same spacing as the grooves and overlapped by
alternating the slices? Just my guess. Wolfgang



Couple of students were just in my office- they are trying to get an
advertising business started and they want to use poster size images
which show different images from different angles (as you move
realative to the poster you see different images). They also have a
sample that has apparent depth (a real image floating in front of a
background image)- very striking to see. This technique is available
commercially but they want to make their own. The ones they showed me
have Frensel lens like grooves on the front surface only all parallel
(not concentric like a Fresnel magnifying lens). They want to know
exactly how to place the image(s) on the back so that you get the
double image effect. Anyone know how this works? I know this is a
diffraction effect but I don't see how to get different images.

kyle
--
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No one ever reached death's door and said:
"Darn! I should have gone to more meetings."

kyle forinash 812-941-2390
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