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When your shades are an intrinsic part of your fancy-dress costume
(Neo, Blues Brothers etc), it can be irritating to have to remove them
to facilitate vision in dark parties/clubs – relegating your persona to a
bloke in a suit.
These shades use the same material as one-way shaded glass, allowing
light in one way but not the other, so you can see everything when it's
dark but you still have your shades on.
Can also be worn by morons on the tube.
[link]
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...or, the glasses could look like very dark glasses but be entirely opaque. The wearer would see the world in front of them in tiny LCD screens on the back of each lens projected into the eye through corrective lenses. This would have the advantage that IR/night-vision modes could be used, and the screens could also support the display of text messages, stock information, song lyrics, chat-up line hints, etc. |
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These are called mirrored sunglasses. |
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Mirrored sunglasses still blot out the sun, or in this case the
ambient light from the bar, so you'd still have to take them
off to see anyone or anything around you. |
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Maybe so, but what you described is still mirrored sunglasses. |
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Then you're right, it is a good name for them. |
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One way glass is still tinted glass, it will still reduce the light reaching the eyes. There is no such thing as a glass that will appear dark from one direction and pass all the light to the other. |
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Do these only work when you're 206 miles from Chicago? |
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Thanks for the link, bigsleep. I didn't know a metal film could photo-bleach (or the reverse of that, actually), though I suspect this effect is confined to surface in contact with silica. This doesn't apply to theleopard's idea, of course, which doesn't say anything about changing reflectivity--it's just the wearing of ordinary mirrored sunglasses indoors. |
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Transmittance, in the dark, of 45%, you're still losing half
your light at any time. |
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Yes, theleopard has the common misconception that a one way mirror is exactly what it says (thus violating the second law of thermodynamics and earning an MFD for bad science.) Instead, one way mirrors work by camouflage--the image from the dim side of a partially reflecting mirror is lost in the reflection from the bright side. |
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[m-f-d retracted] bad science |
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[m-f-d] disputed, since there is actually a way of doing this using a concentric microetched fresnel-mirror-fresnel assembly which delivers better than 86% of incident light to the observer, but with near-zero reflectance to the source (though there is reflectance, it's scattered through 140°). |
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Very useful for concealing large-aperture weapons optics; no glint, in the vis & IR bands they appear black. |
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//concentric microetched fresnel-mirror-fresnel
assembly//
Do you have a handy link for more detail on this? (To save
me trawling through Google...) |
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No, and you won't find one either, so don't bother. |
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I've got a couple somewhere in the shed, but it's dark in there
and I'm damned if I can find them. |
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The skin doesn't absorb(/reflect) all frequencies, equally. So, selecting the filter component(s) to block peaks of skin reflectance will reduce the mirror effect. Downside of course is that for the wearer, other people's faces will be darkened, as well. |
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//a way of doing this ... which delivers better than 86% of
incident light to the observer, but with near-zero reflectance
to the source// |
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Hold on a moment. All you're saying is that there are things
that let light through and don't reflect much of it. This is
hardly rocket surgery. |
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No,we're telling you that they're almost entirely opaque (and absorbant i.e. black) when vewed from one side, yet close to transparent from the other. |
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Not a "one-way mirror", more of a one-way wall... |
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Wow. OK. Turns out [theleopard] got really lucky here, and
this is no longer bad science. [Chairborne Hero], you're
living up to your name. |
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Transitions lenses, anyone? |
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// got really lucky here, and this is no longer bad science. // |
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No luck involved; sometimes it takes reality a while to catch up, is all. |
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<Looks round hopefully for flying car as promised in 1960's/> |
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