Nanofilms to the Rescue
You can hardly throw a buckyball these days without hitting some application of nanotechnology in the light-related industries. OLEDs rely on nanoparticles. Nanostructured films help recapture light in flat panel displays, or diffuse and redirect light for edge-lit LCD panels. Similar layers in thin-film photovoltaic devices increase the efficiency of light absorption. And all sorts of novel display technologies rely on nanofeatures of one sort or another.
But at SID 2009 in San Antonio, Texas, in June, I saw a product that is scheduled to go into production in July 2009 that uses nanostructured film for a novel application. The story is a bit like the tale of 3M’s Post-It Notes; a 3M researcher discovered a new adhesive in 1968, but it wasn’t very good because it didn’t stick very well. The good news was that you could lift it up and reposition it and it would still stick. The problem was that nobody could think of a practical use for it. It was six years later that another 3M scientist thought of using it for bookmarks, and another four years after that before the product was introduced nationally, and it became an overnight success.
A company called Uni-Pixel Displays (www.unipixel.com) has developed a novel display technology that they call “Time Multiplexed Optical Shutter” or TMOS. This uses a light guide with a special film suspended above its surface. An electrical charge draws the film down into contact with the light guide, which allows the light trapped in the light guide to escape. Cover the light guide with a fine matrix of electrodes, and you have a pixilated display.
A funny thing happened on the way to developing their TMOS technology, however. As they developed the special film — which they call “Opcuity” — they discovered that the nanostructures of the film also had another useful property; it does not show fingerprints. The normal procedure in the company’s development labs is to handle everything with rubber gloves. But one day, Dr. Bob Petcavich (VP & GM of Opcuity Films) inspected a new batch of film and didn’t bother to put on the gloves. And he discovered that he did not leave fingerprints on the nanostructured side of the film.
The tiny structures actually wick away the skin oils and spread them into an invisible thin layer on the surface of the film. At the same time, they channel the light from the display in a way that does not detract from its viewing performance. The company found an additional coating that increased the film’s ability to wick away the oil and to add anti-reflective (AR) properties as well. As a result, Uni-Pixel is coming out with its Opcuity Finger Print resistant (FPR) films as a separate commercial product for end-user consumer application.
Why does the world need FPR? You only have to look as far as the Apple iPhone to answer that question. Touch screens are taking over as a preferred approach for user interface design, thanks to the iPhone’s run-away success. (There are reports of people walking up to ATMs and trying to use the “pinch” gesture on their touch screens.)
Uni-Pixel’s FPR films are designed to prevent the fingerprints and smudges from showing in the first place. And it also acts as an AR layer. I’ve been using a sample sheet on my cell phone, and I believe that the film makes it easier to read the screen under certain ambient lighting conditions. And best of all, you can remove the film and replace it easily. This makes it a sacrificial layer; if your screen gets scratched, you just replace the film instead of having to deal with permanent damage.
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