Originally published at: https://boingboing.net/2018/10/03/inspired-by-they-live-the.html
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Erm. Don’t most 3d glasses from the next cinema do this on one eye? Polarization, you know?
Easy to take out the filter from a second pair and put it on the other eye…
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These sound great for when I’m in a pub that keeps insisting on having a million TVs everywhere. I’m trying to have a conversation but the flickering images are a constant draw to the eye.
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Go ahead, you maker you. In fact, did you know that many commonly sold items can be made at home?
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Screens are actually usually polarized at 45° to allow viewing with sunglasses. If you did what you proposed, you wouldn’t see less screen, you’d actually see less of everything else, and more screen due to Bell’s theorem. Sort of the inverse of the desired effect.
Still expensive for polarized lenses.
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Ah, didn’t realise this. So, 3d projection in cinemas is not 45/90°, I take it.
@Boundegar, I wasn’t even wondering about the price difference, but I bet that everyone I know has about 3 to 10 of the cinematic “glasses” somewhere in a drawer…
Still could do this with those.
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Pretty sure that one of the guys I supervise already wears these at work.
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so when I was getting my new glasses last week I picked up a pair of polarized sunglasses. I could see all the screens nearby. when I rotated them a full 90 degrees the screens all blackened. so if the screens are at 45 degrees so are the glasses. I can’t see this project as more than a pair of polarized glasses at the wrong angle. so much $ for that…
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After looking it up, the 3D glasses are slightly different because they are designed to filter circularly polarized light so you can tilt your head in the movie. But if I understand it correctly, they’re 90 degrees to each other, but 45 degrees to the normal, so putting one over the other would block screens… and everything else. The solution is to turn one of the lenses upside down, not put one over the other… based on how I think 3D glasses work.
Of course, none of these options protect your eyes from UV.
Edit: I literally threw away a pair of 3D glasses the other day and now I’m wishing I hadn’t.
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One step closer to a real-life adblocker. Eeeeeeeeexcellent.
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IRL glasses do not yet block smartphones or digital billboards (OLED)
I find that “yet” a tad disingenuous. How would OLED blocking even theoretically work?
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Plus it would have the added benefit of making you look cooler and more mysterious!
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What does “degrees” even mean in the context of circular polarization? Isn’t the only question of orientation one of right or left?
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My polarised sunglasses do this for some screens, depending on the angle I look at the screen. It’s pretty great!
The video advertising thing I pass on my way to work is happily polarised in exactly the right angle to be fully blocked by my sunglasses. My mobile phone screen becomes a little less visible when I look at it in a 45° angle. I got two monitors on my desk at work, same brand, slightly different version number, one gets blocked when I look at it straight on, the other at 45°.
I’m seriously skeptical they will manage to block all those different angles consistently. Maybe they have glasses that are polarised on 0°, 45°, 90°, 135°, 180°, etc and only leave trough the “normal” light that is in between those values, say from 10° to 35° and from 55°to 80°. In that case it may be useful to include a level in the glasses so you can keep your head on exactly straight…
Edit: Alright, I’m a sucker for these kinds of novelty sunglasses… I went over to the kickstarter and they actually mention it doesn’t work on all types of screens:
IRL Glasses are in beta. This means they are compatible with most TVs (LCD/LED) and some computers (LCD/LED). IRL glasses do not yet block smartphones or digital billboards (OLED).
They aren’t very clear on the how-and-why though, which leads me to doubt the effectiveness is as universal as they seem to suggest, who knows maybe in Europe screens are all polarised in metric 
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'im waringgg glases that blocjk my sckreen righy now.
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Very close, but circular polarizers don’t block circularly polarized light, they transmit circularly polarized light and block unpolarized light. And being circular, they don’t have a polarization angle (so tilting your head doesn’t change the angle and mess up the effect), but rather a handedness: right-handed or left-handed polarization, depending which way the light “twists” like a corkscrew as it propagates. Some randomly polarized light, like from a light bulb or the sun, will make it through the circular polarizer by chance, but light that’s linearly polarized at any angle or circularly polarized with the opposite handedness will be blocked almost completely.
In a 3D movie the left- and right-eye images are projected through a pair of circular polarizers, and then each image is only visible through an oppositely-polarized filter (oppositely because when the image reflects off of the projector screen its polarization handedness is reversed). However, just like how flipping over a corkscrew doesn’t change its handedness, neither would flipping over a circular polarizer change its handedness.
Most sunglasses use cheaper linear polarized filters because they block light that’s been polarized by reflection off of horizontal surfaces, e.g. water, the road, or a car hood. But photographers often use circular polarizers because they work in any orientation, and also because linear polarizers interfere with some types of autofocus.
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I have prescription polarized glasses that cost less than this.
My phone is apparently lined up to be read in landscape with such glasses, so in usual use you can’t see the screen with this oarticular pair of sunglasses on. Its a giant pain in the ass.
So yeah just some polarized sun glasses, that are going to make life a pain.
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This isn’t physically possible. Firstly, 0 and 180 are degenerate orientations. But also, the more polarizers you add, the more light gets through. It’s one of the “spookler” quantum phenomena. The only way to reduce the probability of light passing to zero (in an ideal polarizer) is to have two filters that are orthogonal. There may be some other way to block multiple orientations, but not by filter stacking
Here’s a quick explainer:
I didn’t say that circular polarizers block circularly polizarized light, I said that the glasses filter circularly polarized light. They have linear filters in them as well, in conjunction with QWP to convert the circular polarization to linear polarization in a way that’s independent of tilt angle with respect to the wearer, but not necessarily to a third party. Their construction is less trivial than you (or I, initially) realized. At least that’s what the wiki says.
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Circular polarizers simply associate a standard, linear polarizer and a quarterwave plate to transform the light exiting the LP filter to circular polarized light. That CP light behaves like unpolarized for a digital camera, which is the only reason for the requirement.
CP filters behave like a LP filter in front of a screen. They are sensitive to orientation. You can easily try it yourself with a camera filter.
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Whoa! That’s cool! I’m going to learn some fun stuff today, thanks! 
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