Slashdot Mirror
Polymer 'Muscle' Changes How we Look at Color
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."
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.
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.
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?
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.
0 00DA6AC-F10C-1492-A7CE83414B7F0000
c &L=birdchat&P=5566
http://www.sciam.com/print_version.cfm?articleID=
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=ind9512
Nerd rage is the funniest rage.