Please create an account to participate in the Slashdot moderation system


Forgot your password?

Change of Focus for Liquid Crystals 101

Dylan Knight Rogers writes to tell us PhysicsWeb is reporting that US physicists have discovered a new liquid-crystal lens design that can alter the focus by varying the voltage applied. From the article: "The new lens, which has been built by Shin-Tson Wu and colleagues at the University of Central Florida, allows the focus to be changed in a new way. The device consists of a mixture of liquid-crystal molecules and smaller N-vinylpyrrollidone monomers placed between two glass substrates, each of which is coated with a thin transparent layer of conducting indium tin oxide. They then placed a concave glass lens with a flat base on top of one of the substrates."
This discussion has been archived. No new comments can be posted.

Change of Focus for Liquid Crystals

Comments Filter:
  • This could be useful for LCD goggles for people who normally need glasses.
    • Re:Neat. (Score:3, Interesting)

      by Who235 ( 959706 )
      I don't know about that one. I think I'll stick with glasses until they can make the LCDs (and power supplies) small enough to _not_ make me look any more like a frog than I already do.

      I think a more realistic use would be for weapon sights and cameras.
    • Re:Neat. (Score:2, Insightful)

      I hope you don't mean the flickering ones for viewing 3d movies.
      These things would be horrendous for that, imagine the focal length bouncing backwards and forewards 30 times a second, I bet most people would throw up within minutes.

      Eyeglass wearers would be better getting a hud by using the actual ground eyeglass as a substrate for the standard LCD screen than mess around with this dynamic focusing solution.

    • Visualize these in human bionic eyes. But, it WOULD be a problem if they independently focused on the same point to where you're running at bionic speeds...

      hmmm.. slash image world "inbreed"
    • Re:Neat. (Score:1, Interesting)

      by Anonymous Coward
      Screw that, imagine these being used on a monitor, in front of individual pixels, or perhaps groups of pixels... You could emulate depth of field in hardware by playing with how the brain interpets focus!
  • Battery life... (Score:5, Insightful)

    by HateBreeder ( 656491 ) on Sunday May 21, 2006 @04:18PM (#15376978)
    Picture it: A camera that could Auto-focus without any moving, mechanical parts.... faster and more energy efficient!

    I wonder what's the percentage of power drained by a typical digital camera just for auto focusing under normal usage.

    • That was my first thought, too. A camera like that would be incredibly exciting (a cell phone camera that doesn't have to suck)!

      I'm not too familiar with optics or CCD technology, so forgive the question: what's been keeping us from developing a camera based on the same focusing principle as the human eye? Our lens stretches and contracts to adapt its focal length, and it not clear to me why it's been so difficult to adapt this principle to manmade optical equipment. Anyone got an answer?
      • Re:Battery life... (Score:4, Insightful)

        by It'sYerMam ( 762418 ) <thefishface&gmail,com> on Sunday May 21, 2006 @04:38PM (#15377063) Homepage
        Mobile phone cameras suck due to more than their auto-focus. The tiny CCD means they're susceptible to noise, and the lack of decent optics means they won't work well in low light or be able to zoom well - regardless of an autofocussing lens. Furthermore, because an expensive camera has an automatic user filter and learning curve, pictures taken with mobile phones are always likely to be, on average, crap, due to the lack of skill of the photographer.
        • Re:Battery life... (Score:5, Interesting)

          by Dis*abstraction ( 967890 ) on Sunday May 21, 2006 @04:51PM (#15377103)
          Using two lenses with adaptable focus, you'd be able to zoom without needing to change the barrel length, if my understanding is correct. This would simplify the mechanical requirements for variable focus and optical zoom to the point where it would make sense to include both features in consumer electronics.

          Also, there's nothing stopping a professional photographer or cinematographer from putting film behind that felxible lens. Being able to ditch that truck full of heavy glass optics would be a great boon for professionals.
          • Good point. I've not read TFA, and I don't know the variation in focal length you'd get out of those small lenses... It's possible though, especially with technology refinement.
            • Re:Battery life... (Score:3, Informative)

              by gwiner ( 685297 )
              I was a little disappointed after reading the article to see that this seems to be applied more for photonic switching, than camera optics. (Not that those things aren't cool too, but I had visions of self-focusing eywear, and tiny cameras) From the article:

              The only snag with the new device is its long focusing time of about three minutes. This is because the lens is relatively large (9 mm), which means that molecular diffusion across it is slow. However, this should not be problem in micro-sized lenses in

          • Cell phone lenses also suck because they are so small. The diameter of the lens determines not only how much light it can gather but also it's maximum resolution. Since this only works for micro-lenses (their 9mm one takes 3 minutes to focus) it won't work well for even something the size of a cell phone lens and it certainly won't help keep photographers from hauling around heavy glass.
      • Re:Battery life... (Score:4, Informative)

        by Volanin ( 935080 ) on Sunday May 21, 2006 @04:48PM (#15377096)
        Our lens stretches and contracts to adapt its focal length, and it not clear to me why it's been so difficult to adapt this principle to manmade optical equipment. Anyone got an answer?

        We might be not too far from that.
        Check out these Fluidlenses [].
        • Awesome. Thanks for the link.

          It's such an obvious concept that I'm still left wondering it hasn't been translated to manmade optics. FWIW, the lens in a human eye changes its focal length when a muscle pulls it from the outside--nature's simple solution to the problem of giving it adaptable focal length while still keeping it transparent.
      • the human eye has a simple lens that provides focus on a curved (convex) surface. the good focus is right in the center and your eye moves around to maintain focus on whatever you're looking at.

            a regular camera Lens has many elements (glass pieces). even if you could make the glass 'variable', there would still be an amazing amount of complexity to make a clean sharp image on a flat surface (film or sensor).

      • Did you have a material in mind? A durable one that doesn't need to be stored in an aqueous medium attached to a sophisticated chemical regeneration system?
    • It also would be much thinner and lighter, complete with perfect Optical Zoom.
      And with the current advancements in the digital sensors [] technology, soon cameras like the Creative CardCam [] will be possible with greater quality than today's cameras!

      I wouldn't mind carring one in my wallet. =)
    • Re:Battery life... (Score:2, Informative)

      by mikerozh ( 710568 )
      Most of the power is spent on the LCD diplay of the camera.
    • Not nearly as much as is required for the viewfinder. Whenever that's on, my camera sucks down the power.
    • Re:Battery life... (Score:5, Informative)

      by sco08y ( 615665 ) on Sunday May 21, 2006 @05:57PM (#15377289)
      A camera that could Auto-focus without any moving, mechanical parts

      I'm not sure if that would work.

      From TFA:

      The only snag with the new device is its long focusing time of about three minutes. This is because the lens is relatively large (9 mm), which means that molecular diffusion across it is slow. However, this should not be problem in micro-sized lenses in which the estimated response time is around 1 second at room temperature.

      I assume they're talking about lens diameter. It might work for smaller cellphone type cameras, though.
  • "The only snag with the new device is its long focusing time of about three minutes. This is because the lens is relatively large (9 mm), which means that molecular diffusion across it is slow. However, this should not be problem in micro-sized lenses in which the estimated response time is around 1 second at room temperature."

    I take it that means that LCD monitors will not be using this technology any time soon?
  • Nice! (Score:2, Informative)

    by smalgin ( 750257 )
    Wow, a device from the 'Dune'. they had neat binoculars based on the same principle if I remember correctly...
    • Congrats for beating me to the reference. As I recall, in Dune, a droplet of electro-conductive oil served as the lens, providing zoom, autofocus, and adaptive optics in a single system.

  • by flobberchops ( 971724 ) on Sunday May 21, 2006 @04:34PM (#15377047)
    Great scott! *LCD monacle pops out*
  • by rduke15 ( 721841 ) <.moc.liamg. .ta. .51ekudr.> on Sunday May 21, 2006 @04:37PM (#15377058)
    I remember reading 1 or more years ago (here on /. ?) a very similar story about a new lens. It was thought to be used in mobile phones and such, being a very small lens, with no moving parts, focusing being only done through the voltage applied.

    Would someone still have a link to that old story?

  • by xkr ( 786629 ) on Sunday May 21, 2006 @04:48PM (#15377094)
    I doubt this system will replace mechanically focusing a camera lens.

    However, this might be used as a way to optimize solar panels as the sun moves across the sky, or to change the field pattern for headlights or taillights to better match current driving conditions.

  • Augmented Reality (Score:4, Insightful)

    by jonnyboy777 ( 876556 ) on Sunday May 21, 2006 @05:11PM (#15377164)
    Perhaps this could help us on our way to stereoscopic head mounted displays that don't induce migraines after extended use (slight sarcasm here). Current technology primarily plays with parallax while keeping a fixed although often tunable focal distance, but LCDs with many microlenses could vastly help things. The perceived images would be much more realistic, as well.
  • SED [] FTW
  • UCF in the hiz-ouse!

    Maybe we will be known for something besides the guys who did Blair Witch?
    • Hey, we had a hell of a programming team when I was there. And the optics/physics labs there are really top notch.

      Of course, in the spirit of full discosure, my dad is a professor emeritus from UCF, so I'm a little biased.
  • 17/1428223 [] 04/0244233 []
    And another one from the University Laval in Canada whoma was reported on slashdot but don't find the link !
  • A while ago on slashdot there was a story [] about a spiral lens that would enable us to actually see planets of distant stars. Only drawback was that no material known to man is able to construct a lens of such quality. Perhaps with this and other new (as of yet unknown) advances in lens creation technique we will someday be able to construct such a device. The singularity is near......
  • I remember hearing about these lenses at least a few months ago, probably last year even. There was talk that they could someday be implemented into cell phones, letting them zoom to magnifications you normally get with $1000 lenses on professional cameras, simply by altering the voltage applied across the lens.
  • Dupe (Score:3, Informative)

    by brian0918 ( 638904 ) <> on Sunday May 21, 2006 @07:11PM (#15377470)
    This looks like a dupe from a story from last December [], I think.
    • No, that's not a dupe. A dupe is when Slashdot runs substantially the same story twice, typically over a period of a few days. What you've found is an interesting related story from over a year ago.

      I've added it to this story's Related Links, so thanks... but it's not a dupe.

  • by gruthen ( 844338 ) on Sunday May 21, 2006 @08:13PM (#15377631)
    Sharp have an LCD screen [] which can deliver a different image to each eye. These screens allow each eye to see alternate columns of pixels. Combine this (or any other stereoscopic system) with the Liquid Crystal Lense and you'd have a very convincing 3D effect. LCL could also have Occ Health & Safety benefits. Your eyes could be exercised by each window having a different focal depth. Fitter eyes = less need for glasses.
  • Discovered or invented?
    • Evolved. Over millions of picoseconds as incongruent crystals within the lens found resonance frequencies that gradually changed the lens response in an enviroment of an oscillating voltage.
  • This could definitely be a revolution in rifle optics (a.k.a. scopes), I'd love to see someone implement this technology. It would mean a much smaller and more compact device, even with a small battery pack, I just wonder how rugged it could be...
  • Think of all the poor chinese children having to put all of those tiny mirrors on while sweating from the unbearable tin smelting pots.
  • The article states that this technology could have many uses; with more work potentially liquid crystals that can change their thickness could improve current LCD technology.

    One optical property of minerals in rocks in the field mineralogy used in identifying
    minerals is something called interference colors. To characterize the history of a rock and its constituent minerals, sometimes, a rock is cut into pieces and a thin slice is cut from one of the newly cut surfaces. After more cutting and some polishin
  • Adaptive Optics.

    (like the kind used for countering atmospheric distortion in large telescopes and, er. . . giant lasers)

Thufir's a Harkonnen now.