RE: NTLK Oil Slick Screen?

From: Filmer, Paul E (
Date: Fri Apr 28 2000 - 11:29:51 CDT

These are, amazingly enough, called "Newton's Rings" and they have nothing
to do with our PDA's and everything to do with Sir Isaac. You are seeing
interference between light waves reflected off two close-fitting surfaces
that are separated by integer fractions of a wavelength. Each colour in
white light has a slightly different wavelength, so you see them in slightly
different positions. If you look at your screen under a sodium street lamp,
you will notice only yellow & black rings, since sodium lamps have
predominantly yellow light. Also, notice that slight pressure on the screen
will move the rings around - you are changing the distance between the top
and bottom reflecting surfaces. When oil thins out over water, it creates
exactly the same effect, with light reflecting from the top and bottom of
the oil, causing interference.

Now, what can you do about it? Not much. It's not a liquid (unless you
really did spill something on your Newt). The culprit surfaces are deep
within your display, and you are likely to break something by fiddling with
it. Try altering screen viewing angle to minimize the effect. Mine are
only visible when a light is directly reflecting off the screen.

Paul (a fizzicist) Filmer

> -----Original Message-----
> From: Joshua Puetz []
> This is probably a stupid question, but I've combed the FAQ and the
> archives
> without finding an answer, so here goes...
> I've recently acquired an UMP2K, and in bright light I can notice what
> appears to be concentric circles of faint colors between the plastic
> layers
> on my screen...I can only describe it as looking like an oil slick on a
> puddle.
> Is this a result of condensation forming with rapid tempature changes?
> Does
> anybody else have these rings on their Newton?
> -Josh
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