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A comment on How to Convert a Digital Watch to a Negative Display. Parent comment

Re:How to Convert a Digital Watch to a Negative Display by rtpg on Monday April 21, 2014 @09:45PM (#7625281)
>I wonder how practical it would be to make a private display by removing the polarising film from it and then viewing with polarised glasses.

In Japan a lot of people have "privacy" screen protectors on their cells that basically make the viewing angle very small. I always assumed it was through some form of polarization though now I'm not sure.

http://www.trendhunter.com/trends/mobile-privacy-screens-kee...

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Re:How to Convert a Digital Watch to a Negative Display by Cthulhu_ on Tuesday April 22, 2014 @04:23AM (#7626415)
They probably have the same effect as an LCD with a very narrow viewing angle. Modern displays have a pretty high viewing angle; older ones start to change color and become illegible when viewed at an angle. I've seen the same thing on ATMs and the like.
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