Thread: Custom Booklight for the 505 (any interest?)
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Old 10-05-2007, 10:34 PM   #10
obelix
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Join Date: Oct 2006
Quote:
Originally Posted by aapezzuto View Post
Im still looking for the generic term, I found the name of the other flat grooved optic that comes to mind. Fresnel Lens is what i was thinking of before. That monster can melt almost anything using solar power... what happens when you refocus almost 6ft^2 into a 1in^2 space? 738x the heat!!!!

The best idea i have come up with for replicating the concept is getting a piece of lexan and heating it, with something that has the sawtooth pateren on it (like overlaping strips of metal... but that is more .5mm every 3-4mm . Even if i could get a list of products that used this sort of lens, I could get the name probably (calling distributes for parts.)
I dont think it can be done with the grooves more than a few micron size. I tried everything I could find (3d post cards (~0.2 mm grooves), Fresnel magnifiers (~0.2-1 mm groves) etc. They do perfect illumination, but grooved surface distort the screen. Grooves must be really small! Front light plate from Game Boy has a "rainbow" effect at small angles of view, this is because of diffraction/interference at small grooves (they are invisible at regular angles).
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