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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.
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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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I can imagine situations where the ability to quickly remove a visual stimulus would actually help a person with photosensitive epilepsy.
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as you might or might not know, the windshield filters the uv rays. phototropic glasses cannot function in a car.
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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.
Apparently, I have hallucinated the suntan or sunburn that I get on long car trips. Thanks for the info, though!
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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
perl-sensitive sunglasses? sweet!
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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This is not true. Sunburns are caused by UV rays.
http://en.wikipedia.org/wiki/Sunburn#Cause
I'd prefer ones that filtered out COBOL or FORTRAN myself.
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
It filters UV-B and UV-C pretty well, but not UV-A. Phototropic glasses are usually less effective in a car, but not completely useless.
Depending on the wavelength it changes at, these sunglasses could either work great or piss poor. Should be interesting.
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