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Data Storage Toys Science

New Material For Fast-Change Sunglasses, Data Storage 133

Posted by kdawson
from the epileptics-need-not-apply dept.
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.
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New Material For Fast-Change Sunglasses, Data Storage

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  • Slow Memory (Score:5, Insightful)

    by im_thatoneguy (819432) on Sunday April 26, 2009 @04:12AM (#27719691)

    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.

    • Re:Slow Memory (Score:5, Insightful)

      by erayd (1131355) on Sunday April 26, 2009 @04:21AM (#27719711)

      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.

      Who says you have to write things serially? Admittedly write latency would suck, but you can still get a phenomenal throughput if you write a whole bunch of bits in parallel.

      • Re:Slow Memory (Score:4, Informative)

        by BitZtream (692029) on Sunday April 26, 2009 @03:03PM (#27723179)

        Which is exactly what todays 48x burners and hard drives already do.

        I wish people would realize that hardly anything in a modern computer is done serially anymore. Flash drives, standard hard drives, CD/DVD drives, all of them read/write multiple blocks at once to improve throughput without actually doing anything physically faster.

        • by profplump (309017)
          I don't know what your optical drive does, but mine still reads bits serially -- given the physical encoding on typical disks it's really not possible to do anything else. Now it does read whole blocks or even series of blocks in one logical pass, but each bit is read in sequence.

          Really less and less things are happening in parallel in modern computers, because as speeds increase it becomes more difficult to synchronize all the signals -- take a look at PCIe, SATA, SAS, etc.
      • by giorgist (1208992)
        CD stamping comes to mind
    • Re: (Score:3, Insightful)

      by Fred_A (10934)

      Especially if you need to keep the UV source on to keep the data stored...

      • Re: (Score:3, Insightful)

        by EdZ (755139)
        And you need to keep refreshing RAM too. With a refresh every 30ms, this could be used for medium-term storage in an optical computer.
    • by dziban303 (540095)

      Could you imagine a CD burner which takes 30ms per bit?

      No, no I couldn't. Could you help visualize it for me?

      • Sure. Pick your most favoritest CD evar, and hold a lighter under it so the flame just barely touches. Hold until the disc begins to warp. That should give you a clear impression.
    • Could you imagine a CD burner which takes 30ms per bit?

      Could you imagine a CD burner that takes 30ms per CD?

  • Something missing? (Score:5, Insightful)

    by OpenSourced (323149) on Sunday April 26, 2009 @04:22AM (#27719717) Journal

    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.

    • by Jah-Wren Ryel (80510) on Sunday April 26, 2009 @04:32AM (#27719759)

      Of course there might be missing data from the article, but they should explain a bit more.

      That part was written in photochromic ink, you need to get a copy of the original publication and expose it to UV light in order to find out those details.

    • by tsa (15680)

      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.
       
      That's why you have to make sunglasses out of the stuff.

    • If you need to be constantly bathing the material with UV light just to keep it dark, there is not much storage going on,

      I'm not calling the concept feasible, mind you, but do remember that our dynamic memory is currently based on removing and re-applying an electric charge to billions of capacitors hundreds of times per second. DRAM, according to Wikipedia, is guaranteed to hold its state for 64ms. If this one has 30ms, it's not that bad.

      (Or wouldn't be if it could *write* as fast as DRAM does. Of course t

    • 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.

      You need to constantly power your RAM in order to keep it storing information. All it means is that this could be useful for volatile storage.

  • by macraig (621737) <`mark.a.craig' `at' `gmail.com'> on Sunday April 26, 2009 @04:40AM (#27719785)

    ... I'm simultaneously deleting my entire terabyte of porn!? Noooooo!

    • by bobdotorg (598873)

      ... I'm simultaneously deleting my entire terabyte of porn!? Noooooo!

      Hey - keep the UV lamp on. Get off _and_ get tan. Just try not to burn the bits.

  • by oneirophrenos (1500619) on Sunday April 26, 2009 @04:43AM (#27719793)
    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).
    • Re: (Score:3, Insightful)

      by Al Al Cool J (234559)

      Perhaps. But it seems to me that the experience of these things going dark would be very similar to the common everyday experience of simply putting on a pair of sunglasses, something I've done in just about every lighting condition, and usually while driving. The only time I can recall it ever being a problem is when I've done it at night (cue Corey Hart).

      • by Thornae (53316)

        ... usually while driving.

        That's the problem with this and every other UV adaptive lens treatment: Glass (like, for example, your windscreen) blocks UV.
        So, they don't actually work when you're driving.

        This is why I always get frames with clip on sunglasses with my glasses. Although, since I always end up losing the sunglasses part within a year, I'm considering just lashing out and getting prescription sunglasses.

        • Re: (Score:3, Interesting)

          by 0123456 (636235)

          "Glass (like, for example, your windscreen) blocks UV. So, they don't actually work when you're driving."

          Except in my experience that's not really true.

          I had this discussion with my optician last time I got a new pair of driving glasses, and they do darken while driving despite the fact that the windshield should block the UV (though, admittedly, not as dark as they used to go when I drove a convertible).

          I can only guess that the windshield doesn't block the full range of frequencies that cause the glasses

        • by swillden (191260) <shawn-ds@willden.org> on Sunday April 26, 2009 @11:06AM (#27721493) Homepage Journal

          Although, since I always end up losing the sunglasses part within a year, I'm considering just lashing out and getting prescription sunglasses.

          Been there, done that. I lost the prescription sunglasses. Three times. I decided that I just have to squint.

        • Re: (Score:3, Informative)

          by blincoln (592401)

          That's the problem with this and every other UV adaptive lens treatment: Glass (like, for example, your windscreen) blocks UV.
          So, they don't actually work when you're driving.

          Glass doesn't fully block UV. I take UV photos using regular glass lenses with a UV-A bandpass filter in front. I lose something like 3-4 stops of light sensitivity compared to visible, but at least some of that is probably due to the camera sensor not being designed with UV in mind.

          Apparently glass does block UV-B, UV-C, and shorter w

          • by kmac06 (608921)
            It depends on the glass. Typical glass is something like BK7, with a transmission curve like this [atscope.com.au]. You can also get types of glass specifically designed for UV optics, such as fused silica [valleydesign.com].
    • 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.
      • I've taken a couple of welding courses over at Techshop [techshop.ws], 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" tec

    • by BitZtream (692029)

      And that can be fixed with a simple surface layer filter than blocks light from off angles outside a given range.

      This really isn't rocket science, nor is this sort of solution anything new.

    • by ceoyoyo (59147)

      What if the eye (without the lens) were subjected to a bright light from the angle of, say, 0 degrees? This would be blinding, because it would hit the area of high acuity vision on the retina, with no lens to dim. So we would have a situation where the light hitting the retina would not be significantly reduced, but the eye would still be adapted to conditions of relative darkness. We would be effectively blind (think of going outdoors on a bright sunny day).

    • I can't wait for these to become popular. Just walk into a big room and drop an IR strobe light on the table!
  • by LordAlced (1279598) on Sunday April 26, 2009 @04:48AM (#27719801)
    But does it turn dark in the presence of danger?
    • But does it turn dark in the presence of danger?

      Yes. The lenses will leap out of a moving vehicle just prior to impact, while the driver cries "It works, it works!". Eventually, he will wake up in the hospital believing that he's really Leon Trotsky.

  • 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.

    • Radio waves are just a type of electromagnetic wave right? So they would be called photochromics too.
  • by MichaelSmith (789609) on Sunday April 26, 2009 @04:53AM (#27719819) Homepage Journal
    I can imagine situations where the ability to quickly remove a visual stimulus would actually help a person with photosensitive epilepsy.
    • by maroberts (15852) on Sunday April 26, 2009 @05:31AM (#27719971) Homepage Journal
      Not to mention waking up in the morning and turning round to face the hideously ugly person you picked up at the bar the previous night.....
    • Re: (Score:3, Insightful)

      by failedlogic (627314)

      People should realize that not everyone who is epileptic is photosensitive. Many people seem to have the incorrect impression that flashing lights and such will trigger off a seizure with anyone that has epilepsy. This is a myth.

      • This is a myth.

        More of a meme I think, at least in the context we are seeing it here. I developed a seizure disorder when I was at college. A friend started to act like I had AIDS. Making a big deal out of something which was for me simple and easy to keep under control.

        Another friend of mine has some degree of photo-sensitivity. The biggest problem she described to me was the intense flashing sunlight caused by driving past trees with a low sun angle. One moment the sun is right on your face, then it is dark again. Gla

    • by Spit (23158)

      Peril sensitive?

  • (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 like

    • Re: (Score:1, Insightful)

      by Anonymous Coward

      FTA- "And the compound is so stable that the reactions can be repeated thousands of times."

      Without doing the math(s), driving along a tree-lined road ought to kill 'em in a few hundred metres.

    • by dunkelfalke (91624) on Sunday April 26, 2009 @05:22AM (#27719945)

      as you might or might not know, the windshield filters the uv rays. phototropic glasses cannot function in a car.

      • by boog3r (62427)

        did not know that.

        also, i never said anything about a car :)

      • by gaggle (206502)

        Convertible?

      • by DNS-and-BIND (461968) on Sunday April 26, 2009 @07:07AM (#27720289) Homepage
        Apparently, I have hallucinated the suntan or sunburn that I get on long car trips. Thanks for the info, though!
        • Apparently, I have hallucinated the suntan or sunburn that I get on long car trips. Thanks for the info, though!

          Commonly known as a trucker's tan.

          On your next trip, I'd suggest wearing a wife beater [wikipedia.org], and maybe some shorts with black socks. I'll guarantee your new tan lines will confuse rednecks, truckers and your fellow nerds. Freaking out the wife and kids is a bonus.

        • Well, glas doesn't filter UV completely, but almost. That is the reason for using special quartz glas for UV optics and applications.

        • by drawfour (791912)
          Not completely sure, but I think only the windshield filters out UV rays. Your tan/burn from long car trips is probably happening due to UV coming through the side windows.
      • by Inda (580031)
        My eyesight went downhill about five years ago. I stumped up the extra hundred quid for my photochromic (is that what you meant?) lens. I was so annoyed that no one told me they don't work in the car.

        My solution was to drive with my head hanging out the window. You have to keep your mouth shut because of the bugs-of-teeth issue, so conversation with passengers is near on impossible.

        Seriously, I couldn't live without them these days. If the time from dark to light was reduced it would be fantastic.
        • yes, photochromic is the english word for it, sorry, i used the german term for it by mistake.

      • by Bigjeff5 (1143585) on Sunday April 26, 2009 @12:39PM (#27722109)

        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.

      • by BitZtream (692029)

        It filters some, not all. Ever notice you can still get a sunburn in a car, it just takes longer.

      • by ceoyoyo (59147)

        Sure they do. I used to have a pair, of the slow change ones, of course. Whenever I left them on the dashboard they'd be good and dark when I put them on. Also hot.

    • I'm going to regret it but where the hell did you get the up to 72fps number and if that's true why can almost anyone see the difference between a 75hz refresh rate and an 85hz refresh rate on a CRT.

      • by fbjon (692006)
        FPS numbers for human eyes are not trivially measured. There's a big difference in a moving image, and a flickering image. For instance, almost nobody will see the difference between video at 100fps and 120fps. Even so, you would immediately notice if a white screen at 120Hz turned black for just one refresh, then white again.
  • by misterjjones (1331965) on Sunday April 26, 2009 @05:32AM (#27719975)
    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.
    • Re: (Score:3, Informative)

      by tresstatus (260408)
      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 t
    • by An ominous Cow art (320322) on Sunday April 26, 2009 @11:58AM (#27721819) Journal

      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

  • when Britney Spears suddenly is in sight.
  • by Anonymous Coward

    So with a little work, we can finally have the Peril-sensitive sunglasses of Zaphod's fame.
    Sign me up for a set.

    • Re: (Score:3, Funny)

      perl-sensitive sunglasses? sweet!
      • Re: (Score:2, Funny)

        by Anonymous Coward
        Those would be useful too, and actually a lot more feasible with current technology. Just add a camera, a microprocessor running OCR, and a perl parser -- and turn the glasses opaque the moment the parser finds legal perl code. This could save millions of young programmers from brain damage. The only problem is to create software that can distinguish between perl code and random OCR errors.
      • by 1u3hr (530656) on Sunday April 26, 2009 @09:16AM (#27720829)
        I'd prefer ones that filtered out COBOL or FORTRAN myself.
  • dark blue is useless for sunglasses, you need (dark) brown....
  • by markdavis (642305) on Sunday April 26, 2009 @07:27AM (#27720377)

    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 :)

    • Re: (Score:2, Informative)

      by miggyb (1537903)
      Isn't that exactly how LCDs work? When no charge is applied to a liquid crystal, it lets light through, but when there's an electrical charge, it becomes dark. All you'd really need is a pair of glasses with a battery, photodetector, and two monochromatic LCD cells the size of the actual lens. I don't think it'd be that much of a pain in the ass to have to recharge your glasses at night.
      • I'm pretty sure that the light coming from a white pixel on an LCD is linearly polarized. LCDs have a polarizing filter, then a liquid crystal that can polarize the light at a voltage dependent angle, than a perpendicular polarizing filter. If your liquid crystal layer is oriented parallel to either the front or back layer, then no light gets through. If it is oriented at 45 degrees to both front and back, then you get maximum brightness.

        Unfortunately, if your light source is unpolarized to start, then
      • by maxume (22995)

        It probably wouldn't be that big a pain in the ass, but most people want sunglasses that they think look good, not sunglasses that can be switched between clear and dark on demand, so it better not cost a lot extra (lots of sunglasses charge for the logo, so those would be easy to compete with on price, but you would be doing so at the cost of quite a bit of margin).

        • by mark-t (151149)
          You are correct, although consider that most people who would want sunglasses that could also go clear probably wear prescription glasses already and do not want to deal with the hassle of switching to prescription sunglasses whenever they go for a drive or using a clip-on filter.
    • Re: (Score:3, Informative)

      by fahrbot-bot (874524)

      Yet, there is no way to have changing, polarized lenses (right now).

      Although this won't help inside a car (as the windshield blocks UV), Transitions lenses can be polarized. As an alternative, they also offer Drivewear [drivewearlens.com] lenses that are polarized and respond to both visible light (less darking) and UV light (more darking). These are also available from Oakley [oakley.com].

  • What's new? (Score:5, Interesting)

    by ChrisMaple (607946) on Sunday April 26, 2009 @08:14AM (#27720579)
    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?
    • Re:What's new? (Score:4, Informative)

      by pereric (528017) on Sunday April 26, 2009 @08:33AM (#27720643) Homepage
      Maybe that it doesn't need external power or control. IIRC, the auto-dim welding helmets I know of need an external power source (small solar panel + battery I presume), and dims by applying a current to the glass. I was also going to ask if this could be used for a simpler welding mask, but 30 ms is perhaps too slow for protecting against the lots of UV arc welding produces.
      • Not positive but I assume the "solar cell" is to detect the light from the arc, might not be that difficult to substitude a much smaller photo-electric cell and a hearing aid batter for the much larger versions used in welding helmets. Welding helmets are personal proctective gear where failure can lead to significant injury so they are over-engineered for saftey.

    • by kheldan (1460303)
      That's LCD technology. There are photovoltaic cells on the mask powering it.
    • Yikes...it doesn't go dark until it detects the UV from the welding arc? That would mean there's a short period of time where your eyes are getting a nice blast of UV. Anybody know how short it is?

      I think I'll just stick with the manual flip-down glass, thanks.

      • by NeMon'ess (160583) *

        Why so dismissive? What if the amount of UV is comparable to flying across the USA five times a year? Maybe it's even less. Dismissing it when you don't have enough information makes you look irrational and reactionary. Or maybe the flippant last line was just a weak joke.

        • I'm not one to trust a safety device without knowing how it does its job better than what it's supposed to replace. If that makes me look irrational and reactionary, then I'll just be an irrational and reactionary luddite with a flip-down welding visor.

      • by vlm (69642)

        That would mean there's a short period of time where your eyes are getting a nice blast of UV. Anybody know how short it is?

        A classic "when did you stop beating your wife" class of question.

        The glass doesn't transmit UV at all, at any time. The only common substance that is clear and transmits UV is Quartz (or fused silica which is more or less the same substance). Because it requires a much higher temperature to work than plain ole glass, its not used much, other than in UV spectrophotometers, UV sterilization lamps, eprom eraser bulbs, etc.

        However, I would not be surprised to if the Chinese "accidentally" sent us a batch of

  • 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.
    • Re: (Score:2, Informative)

      by rockNme2349 (1414329)

      They are activated by ultraviolet light...

      Since they turn dark blue, I'll let you figure out what type of light they filter out.

      • by mark-t (151149)
        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.
    • by BitZtream (692029)

      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.

      • by mark-t (151149)
        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 al
  • 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 -

With all the fancy scientists in the world, why can't they just once build a nuclear balm?

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