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Polymer 'Muscle' Changes How we Look at Color

Posted by ryuzaki0 on from the what-color-can-you-flex dept.

New Scientist is reporting that in the not-so-distant future computer monitors, and televisions may utilize a color changing polymer that responds to a current instead of existing techniques. From the article: "Aschwanden and colleagues built arrays of 10 pixels, each 80 micrometers across. The pixels consist of a piece of polymer covered with ridges tipped with gold. When white light is shone at the polymer from one side it reflects out of the screen and is also split into different wavelengths by this 'diffraction grating'. However, a slit above the polymer ensures that only one wavelength of light escapes, giving the pixel its color. The pieces of polymer also contract in response to current, like simple muscles. As they do so, the fan of light-waves is moved, changing the color that is fed through the slits above and out of the screen. Cutting the current causes the muscle to return to its original state."

9 of 74 comments (clear)

  1. Application in fiber optics? by chriss · · Score: 4, Interesting

    I like the idea of reducing our current RGB model to a "true pixel" technology, because it will make displays smaller, sharper and more. But as far as I understand our vision system is itself based on a sort of RGB sensor and the human eye is not really capable of seeing e.g. orange, which is why the whole RGB (and CMY) display technology works in the first place. There are some high range displays (at least in research facilities) giving you a larger dynamic per color than the 256 scales of traditional 24 bit images, so the lack of "true colors" mentioned in the article might be solved by conventional technology.

    But what about the use for data transfer over fiber? One of the nice things about fiber is that you can send several "colors" in parallel which will not disturb each other, something impossible with copper. Up till now they use laser diodes with a fixed wavelength, so the number of diodes determines how many parallel signals you can send.

    Now there is a technology that can create any wavelength. Combined with matching optics, could one not use one of those polymer displays to create multiple wavelength signals and send them through one fiber, in theory allowing an indefinite number of signals? Still limited by the number of pixels on the display and the accuracy of the sensors on the other side, but much easier than to arrange several thousand laser diodes.

    [Just speculating, no real clue about optics.]

    --
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    1. Re:Application in fiber optics? by Anonymous Coward · · Score: 5, Informative
      One of the nice things about fiber is that you can send several "colors" in parallel which will not disturb each other, something impossible with copper.


      This is not true.


      Different colours are simply different frequencies of light. You can also send different streams of data on different carrier frequencies over a copper transmission line.


      This is used all the time, eg. in cable television: you get several television signals in parallel through a single coaxial cable. This is possible because each channel has it's own carrier frequency.


      It however is true that the bandwidth of an optical fibre (of course at the frequencies used there) is much much larger.

    2. Re:Application in fiber optics? by Anonymous Coward · · Score: 3, Informative
      Now there is a technology that can create any wavelength. Combined with matching optics, could one not use one of those polymer displays to create multiple wavelength signals and send them through one fiber, in theory allowing an indefinite number of signals? Still limited by the number of pixels on the display and the accuracy of the sensors on the other side, but much easier than to arrange several thousand laser diodes.


      Maybe, but the problem in high-speed fibre optics isn't creating all the different wavelenghts, it's modulating them fast enough that's the real challenge.


      In order to get to a useful system, each of these 'colours' have to be modulated, ie. switched on and off according to the bits you want to transfer. So you need to be able to switch on and off at a rate of at least a few gigahertz.


      Moving polymer molecules are a bit similar to current LCD technology, in which liquid crystal molecules also physically move. Such processes are inherently slow. You can't find LCD's whose pixels can switch faster than a few milliseconds. That's far too slow for fibre optics.

    3. Re:Application in fiber optics? by vidnet · · Score: 3, Informative

      But as far as I understand our vision system is itself based on a sort of RGB sensor and the human eye is not really capable of seeing e.g. orange, which is why the whole RGB (and CMY) display technology works in the first place.

      Yep. Red, green and blue are not divinely chosen as primary colors, they're based the peak sensitivities of human eyes. Human color vision is based on three different types of light sensitive cells, each with overlapping bell curves of sensitivity. A color within the human range will excite these different kinds of cells to different degrees. Yellow light will trigger red-sensitive and green-sensitive cells, basically decomposing the color. However, red light and green light will obviously also trigger the red-sensitive and green-sensitive cells, and the brain is incapable of telling the difference (other animals with different primary colors might, though).

      Now the problem with this approach is that RGB display equipment usually works by emitting the primary colors side by side, as becomes apparent if one spills a drop of water on a screen (or use a magnifying glass). This results in some inherent color bleeding that this new technique will resolve.

      It's hard to tell how significant the change is, at least for us humans, since all of our current full color display techniques are RGB based (with the possible exception of non-cmyk paints), but isn't it worth it just to let our dogs watch Lassie in their own color spectrum?

    4. Re:Application in fiber optics? by maxume · · Score: 3, Informative

      It's gone paywall online, but a recent edition(June or August) of Scientific American has an article about bird vision, with comparisons to mammalian and human vision.

      http://www.sciam.com/print_version.cfm?articleID=0 00DA6AC-F10C-1492-A7CE83414B7F0000

      There are nifty diagrams showing the different pigments present in the different eyes and their sensitivities. Another interesting factoid, birds have oil droplets associated with their color sensing cells; the droplets narrow the spectrum that the cell is sensitive too, increasing the birds ability to see color. The relatively poor color vision of humans is ascribed to mammal's rather nocturnal evolutionary history.

      A somewhat related posting by the author of the article:

      http://listserv.arizona.edu/cgi-bin/wa?A2=ind9512c &L=birdchat&P=5566

      --
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  2. Potentially neat. by CosmeticLobotamy · · Score: 3, Interesting

    For certain applications. It's my understanding that usually the synthetic muscle stuff isn't particularly speedy in changing shape. My first question is how many flips per second can you get? Are we aiming for TVs or variable paintings? My second question is about power requirements. 300 volts, sure, but are we talking amps or microamps?

    Neat, as most science is, but possibly not terribly useful.

  3. Requires lots of bandwidth for (uncompressed) data by Zarhan · · Score: 3, Interesting

    So we have a "pixel" that can be truely any color. Does it mean "any" color, as in Hue, or can it truely be of anything (ie. full spectrum output; Image of fluorescent light would have spiky spectrum, etc.). If the former, instead of RGB we can simply transmit HSV (Hue-Saturation-Value(Brightness)), but if it's a continuous spectrum...

    Instead of transmitting just RGB values from 0-255 (24 bits) per pixel, instead you have to somehow convey the entire spectrum. At what resolution do you get? Instead of three values (R, G and B) do you get 400 (one per nanometer, from 300 to 700 nm?) - or 4000? What kind of format do spectrograms use?

    Anyway, consider transmitting data from a spectrogram - times some standard monitor resolution - for multiple frames per second. That's a lot of uncompressed data.

  4. 10 pixel display... by Fishead · · Score: 3, Funny

    ...Sweet! That's almost as good as the camera on my cell phone!

  5. Tetrachromats Rejoice! by QuantumFTL · · Score: 3, Interesting

    The ability to generate any visible light frequency would not only extend the gamut to the full human range (unlike other schemes, like the 6-color Iridori system presented at SIGGRAPH 2004), but it would also allow tetrachromats to enjoy television and computers much better (this issue was discussed previously on slashdot).

    Of course, as the article suggests, they will still have to use multiple emitters per pixel, as it can only generate colors on the edge of the CIE Color Space (warning, you can't see what colors they are, because your monitor cannot display anything outside the RGB Triangle). And of course tetrachromats are rare but have been found.