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New Material For Fast-Change Sunglasses, Data Storage
sciencehabit writes "'Researchers have developed a material that almost instantaneously (30 ms) changes from clear to dark blue when exposed to ultraviolet light, and it just as quickly reverts to clear when the light is turned off. The new material, one of a class called photochromics, could be useful in optical data storage as well as in super-fancy sunglasses.'" A comment to the article notes some of the potential dangers of quick-change sunglasses.
30ms is pretty slow by memory standards.
Could you imagine a CD burner which takes 30ms per bit?
It'll need to get a LOT faster to be used in any kind of processing or storage medium.
Nowhere in the article they mention how the data is going to be 'stored'. If you need to be constantly bathing the material with UV light just to keep it dark, there is not much storage going on, IMO. Of course there might be missing data from the article, but they should explain a bit more.
Rome taught me patience and assiduous application to detail. Virtues which temper the boldness of great, general views.
Who in their right mind would want blue sun-glasses? For use on planet earth at least...
But the googles, they did nothing !
no text
... I'm simultaneously deleting my entire terabyte of porn!? Noooooo!
It's all good and well, but the eye doesn't adapt to changes in lighting as fast as this material does. What if the lens (and the eye) were subjected to a bright light from the angle of, say, 70 degrees? This wouldn't be blinding, because it would not hit the area of high acuity vision on the retina, but would nevertheless cause the lens to dim. So we would have a situation where the light hitting the retina would be significantly reduced, but the eye would still be adapted to conditions of relative brightness. We would effectively be blind (think of going to dark indoors on a bright sunny day).
But does it turn dark in the presence of danger?
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Does anyone know if a material exist with similar reaction to radio waves and what such a material is called?
Materials called radiochromics normally react
to radioactive radiation not radio waves.
I can imagine situations where the ability to quickly remove a visual stimulus would actually help a person with photosensitive epilepsy.
http://michaelsmith.id.au
(not sure why i posted this on their website. i blame the booze).
Did a bit of math and figured out that at 60mph you would need a complete obstruction every 2.5 feet to induce a state change (on-off), 5 feet for a full flicker (on-off-on).
This compound cycles on-off 33.333 (repeating, of course) times/sec. Halve that for a full on-off-on cycle. The human eye can do fine with a video frame rate of 30/sec, but can detect up to 72 frames/sec.
It is possible the flicker may induce optical illusions, but not likely considering the optimal cycle time produces the highest flicker rate. Any UV transition slower will produce less flickers/sec, while a faster transition will create an increasingly static tint (chemical can't transition quickly enough).
Now sitting under a 60Hz black light, that may be kind of trippy.
signatures are for fools with hands
The biggest problem with current photochromics in sunglasses is not the speed, but the fact that they darken beautifully in strong sunlight, but only when it's cold.
In hot conditions the temperature sensitive dark=>light process is favoured over the uv sensitive light=>dark process and they stay clear. I don't want glasses that change colour quickly, I want glasses that change stay dark on the beach.
The only use I have for my current "light sensitive" glasses is if I ever go to the Arctic in summer.
when Britney Spears suddenly is in sight.
So with a little work, we can finally have the Peril-sensitive sunglasses of Zaphod's fame.
Sign me up for a set.
dark blue is useless for sunglasses, you need (dark) brown....
Although it sounds interesting, I doubt most people are going to want to look at the world through blue-colored glasses. What would be far more useful would be glasses that the *user* can decide when they turn dark and by how much. 80% of the time I wear sunglasses is in the car, and Transitions and other UV activated glasses are useless for that purpose because they won't change dark.
I also find that polarized sunglasses are *far* more valuable than just plain darkening glasses. Yet, there is no way to have changing, polarized lenses (right now). So.... give me glasses that can change from 100% clear to full polarized (50% dark at least), on-demand, instantly, and I will then get very excited :)
I believe you are totally missing the point for the light sensitive glasses. they are never meant to be sunglasses. they are meant to protect your eyes from UV rays so that you don't damage your eyes. they also only barely darken anything you are looking at, with it being most noticeable on white things, like clouds or sheets of paper. what they really excel at is taking the edge off when you are looking at an object that is extremely bright........ EXCEPT FOR THE SUN. you aren't supposed to stare at the sun while you wear these.
I wear glasses that have the newest version of the transitions lenses. they turn much faster in heat than they do in cold... just the opposite of the older version. even still, when i wear them, i can't tell that they've changed to dark until I take them off and look at them.
my advice is that if you want your prescription glasses to work on the beach, you have 3 options: buy prescription sunglasses, buy a style of sunglasses that comes with a built-in clip-on (usually magnetic), or get contacts and wear regular sunglasses.
stephen
I've used a welder's face shield that changes to dark in the presence of UV from welding faster than I can perceive. It changes back to clear when welding stops. Am I missing something that makes this new?
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Sure it can protect your eyes against potentially harmful UV radiation, but when driving, the car windshield is already blocking a lot of that... of course, it doesn't stop bright light from getting in though, and when driving west in the evening, particularly just after a shower and the sun has come out, something that automatically goes darker in bright light alone, even if the UV isn't particularly high, would be just as, if not more useful.
File under 'M' for 'Manic ranting'
I think we could use this for more then just sunglasses. What about using it in a high rise building. I'm sure some architect could work having blue windows into the design of the building. Or what about if your office had blue windows during the day to give a nice calming blue tinge to the work environment but at night turned clear to allow a clear view of the city? I could see airlines (Virgin Atlantic specifically) installing these since they already have blue interior lights. What about night time use - does the small amount of UV light given off by a star cause it to appear blue? I think there's more possibilities then just sunglasses or data storage.
They are activated by ultraviolet light...
Since they turn dark blue, I'll let you figure out what type of light they filter out.
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I've been wearing glasses with photogrey lenses since I was about 8, so 35 years or so. I've never noticed a problem with them failing to darken in hot weather.
Larry
Interesting...but it suggests another use. What about safety goggles? 30ms seems to be considerably less than human reaction time to visual stimulus (190s grabbed from Wikipedia - no idea whether this is accurate for blinking). So this might be good for laser safety goggles - assuming it absorbs the correct wavelengths.
Doesn't help matters while driving if they are only activate by UV, since most UV doesn't actually get through a windshield, so the glasses would stay clear.
File under 'M' for 'Manic ranting'
UV filtering glass filters some, not all of the UV. Take a nice long car trip with the sun shining on you through those UV filtered windows, you'll still get tanned or burned given enough time.
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That's because the side windows aren't shielded... my point is that glasses that automatically change from clear to dark in sunlight are almost useless while driving because they don't get exposed to enough UV through just the side windows. They'll go dark if the sun is lower in the sky and to either your left or to your right, but not so much if it's in front of you, which is where it would be most useful. Sure one might say that for that they should use real sunglasses, but they are a hassle when one already wears glasses, which is why they ever invented lenses that automatically go dark outside in the first place. I just wish they'd respond as well to plain old bright light, and not require UV to set them off.
File under 'M' for 'Manic ranting'
Nor me, but what I have noticed is that mine get much, much darker in the winter. I always attributed that to the additional UV radiation reflecting off of the snow, but maybe the temperature is also having an effect like the OP says.
Either way, it makes it really fun to enter a nice warm building; between the condensation and the tint, I go blind!
I've taken a couple of welding courses over at Techshop, and there's a range of welding goggle technology out there. Electric-arc welding (MIG, TIG, old-style stick, etc.) needs really dark goggles, and photo-sensitive welding goggles are available and really cool. They're adjustable-strength, and I think the technology is LCDs driven by a photocell, as opposed to a purely chemical mechanism like sunglasses. (For gas torch welding, the glasses don't need to be as strong, and the standard "adjustable" technology is just flip-up green lenses.) Unfortunately, the automatic ones cost about $200, as opposed to non-adjustable welding helmets that are usually under $100 or torch-welding goggles that are priced like sunglasses.
If this technology is dark enough for welding, ,and not too expensive it's fast enough to be effective.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
sunglasses? what for? you can't tell me that slashdotians actually go out in the sun.
To do something right, you often have to roll up your sleeves and get busy.
would be fast enough for 3d glasses
Nothing says 'beat me up, I'm a geek' like a set of photochromic glasses...
Non-Linux Penguins ?
If it's not too expensive it would be cool to paint a car with it - that would really freak people out.