Inspired by 'They Live,' these glasses block screens

[AndreStmaur]

@Entity447B

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.

I never see that in Europe. I was surprised to see screens every when visiting the USA.

[arteitle]

@reactionabe

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.

You’re right, it looks like the filters in e.g. RealD glasses are less straightforward than I realized, and I admit optics isn’t my area of specialty. It looks like they permit some of the circularly-polarized light with the correct handedness to pass through in the form of linearly-polarized light, rather than just letting all of the circularly-polarized light through. But since our eyes are not (significantly) sensitive to the polarization of light, it doesn’t matter what the orientation of the linearly polarized light is when it reaches the eye.

[reactionabe]

@arteitle

I admit optics isn’t my area of specialty.

Damnit Jim, I’m a chemist, not a physicist–so I might be wrong about something here.

[arteitle]

@AndreStmaur

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.

From the Wikipedia article it looks like what you’re describing is one type of circular polarizer for creating circularly polarized light, but a homogeneous circular polarizer is one that passes through light with circular polarization unaltered, so it wouldn’t have an orientation, just a handedness, which is what I was talking about.

[Entity447B]

Here in the UK it depends on the place - and how much of an emphasis they place on getting customers in to watch the football.

[euansmith]

Just reverse the polarity of the neutron flow, and everything will be hunky-dory.

[reactionabe]

Nerd Sniping

[Robbo]

I still like my Adafruit TV-B-Gone. Works like a charm.

[generic_name]

My sunglasses are polarized, and I’ve noticed that some computer screens are completely obscured, while others are OK, so his glasses may not block every screen.

[euansmith]

My sunglasses are polarized. The left lens has formed a Communist Collective, while the right lens has gone full Libertarian Kleptocracy. [I think that probably sounds best if read in a Tommy Cooper voice]

[Ryuthrowsstuff]

I doubt they could. Because its all a factor of screen orientation. Different types of polarized lenses can block different types of reflections/orientations of screen. But I doubt you’ll be able to block all them screens with one set of lenses.

I also don’t really see why you’d want to. Like I said my sun glasses do this to a certain number of screens and its an annoyance. Yesterday I was attempting to order a sandwich and had only brought my sun glasses with me. They blocked the screen with the specials listed on it, but the screen was too far away to read with my specs off. I’ve had similar problems at airports and train stations.

Less of an issue if you don’t have bad eye sight and perscription sunglasses (also contacts) but I’ve definitely had situations where the issue was bright sun made it difficult to read some important screen, but the sun glasses made it impossible.

Strikes me as a novelty item feeding of an “I don’t even have a TV” smug party.

For $80 bucks. And I fail to see what the fuck these have to do with They Live.

[Glaurung]

To be true to the spirit of the movie, I think I will wait for the aliens to take Mr Cash away, and then I will take a pair from one of the boxes of sunglasses lying around his abandoned HQ.

[anon3072533]

@euansmith

making you look cooler and more mysterious!

Question for anyone here–do they have to be dark glasses (sunglasses)? Can you have a clear lens that polarizes?

[Groundman]

They should make them in toddler sizes.

[LutherBlisset]

@arteitle

But photographers often use circular polarizers because they work in any orientation, and also because linear polarizers interfere with some types of autofocus.

Also, because you need to tilt your camera otherwise to get the clear blue sky or the reduced reflection on surface. And some filters actually spin with the lens when zooming, AFAIR. I haven’t used my DSLR since 2016, I think, so maybe the last point is bogus.

[n1h80k4TStjgpQ]

What am I missing in the first few seconds of the They Live clip? It seems like Mr. Piper’s character is reacting to the glasses while looking at the tiled (?) sidewalk though them. Why?

[Keith_McClary]

@Ryuthrowsstuff

They blocked the screen with the specials listed on it, but the screen was too far away to read with my specs off.

You have to turn your head 90 degrees. Pain in the neck.

[AndreStmaur]

@arteitle

@AndreStmaur

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.

From the Wikipedia article it looks like what you’re describing is one type of circular polarizer for creating circularly polarized light, but a homogeneous circular polarizer is one that passes through light with circular polarization unaltered, so it wouldn’t have an orientation, just a handedness, which is what I was talking about.

You are right, but only the type I am talking about is sold as filter for cameras. Your type is possible and indeed may be used for 3D applications, although all the glasses I could try used linear polarizers.

[Ryuthrowsstuff]

I take the specs off and hold them sideways in front of my face.

I need a new pair of sunglasses. They won’t be polarized. There’s not much benefit for normal regular use. And I haven’t been doing the outdoorsy shit they supposedly work best for often enough to keep dealing with the regular annoyance.

[SenorSchaffer]