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Scientists at the University of Toronto has succeeded in switching speed of a new, photonic crystals based screen material to a tenfold increase. The matter raises bright, intense light - in every color of the spectrum from red to blue. Toggles are simply different tensions created. The technology could be bright, flexible color displays allow in many areas of application could be used - from the poster board up to the reader for electronic books. "It is the only material on earth, that its color from UV light up in the Nahinfrarotbereich it can change," says chemistry Professor Geoffrey Ozin, who heads the research team.  Readers like the Amazon Kindle, the Sony Reader or a new unit from the
British-German manufacturer Plastic Logic previously put on a black and
white of the Boston technology manufacturer E-Ink. This so-called
electronic paper, also called e-paper reflects light, rather than on
its own, which is the technology and energy saving even when sunlight
is easy to read. Monitors with a color version of the E-Ink technology
will in the next few years on the market. These are the pixels into
three sub-pixels with red, green and blue filters subdivided. Subpixel
this light is mixed in different intensities, in order to produce
different colors. "This means that only one third of the total number
of pixels, for example, red can represent," says Jacques Angele,
co-founder of the French e-paper company Nemoptic. This would reduce
the brightness by almost a factor of three. The main advantage of the technology of Ozin now is that the photonic crystals to ensure that each pixel can be set so that it represents a specific color. "In principle it should be a good result in brightness, the more paper is printed, when compared with the current e-paper technology compares," said Angele. The increase in the speed with which the material changes its color, bring the approach now taking another step towards practical applications. The University of Toronto researchers report in their paper in the journal Angewandte Chemie "appeared even further improvements in the coverage of the color spectrum. With Opalux has already found a company that wants to commercialize the technology. They used the material to prototypes to create colorful displays. Currently glass is used as a carrier, but also the material could easily be on a flexible substrate is raised, believes Andre Arsenault, co-author of papers and co-founder of Opalux.  Photonic crystals are nanostructures, whose refractive index fluctuated
periodically - the natural model of photonic crystals are opals. The
so-called "About Grid" of the refractive index variations are photons
with the "correct" wavelength bent, that is deflected or reklektiert.
By a slight variation on the composition of the material, the color of
the light to change, which reflected. Initially Canadian researchers
used the stack of hundreds of quartz Nanokügelchen contained in a
polymer were integrated. These stacks were then combined with an
electrolyte material, a material that directs ions, between two
transparent electrodes, coated with glass were packed. There were now
different tensions created, moving the electrolyte material from the
polymer, or even back out into it - it swelled and shrank back. That in
turn led to a change in the interval between Nanokügelchen so that the
wavelength of reflected light has been affected. The main change in the new material present generation now is that there is no longer contains quartz. Instead, the Nanokügelchen in an acid solution dissolved. This process can be a porous, net-like polymer structure, the properties of photonic crystals aufweist. The pores are then filled with electrolyte material and all that then squeezed between electrodes. This creates a much wider area of contact with the electrolyte material of the polymer surface, making it faster and more evenly distributed. The colors are also faster and also the possible number of colors increases. "If the active polymer beads filled with quartz, there is no place for the electrolyte materials, back and forth to walk," says Arsenault, to the ground around the structure to arrive, it should be the whole way down diffuse. "That can be quite long." The new material has the E-Ink screen technology in terms of switching speed übergeholt. The picture points from photonic crystals can color in less than a tenth of a second change, says Arsenault. E-Ink creates loud Saved only one-fifth second. (His company is working Nemoptic however its own material, even a hundredth of a second to reach.) Angele says that one disadvantage of photonic crystals it is that the electrolyte flow is always in response to electricity will be changed. This electrochemical cycle resembles the rechargeable batteries: "For this reason it may be the same problems that we know from this area - with the time it just after the performance." To establish a practical display, the University of Toronto researchers to ensure that their device creates thousands of cycles. A precise control of the quantity of electrolyte, which pours into the polymer to a certain color to achieve, according to Angele also not easy to reach. There are other hurdles. The dots are easier to change from short to long wavelengths (from blue to green to red), but a reversal of direction is harder. The pixels must also have a higher color contrast. The researchers hope their material so with the help of nanoparticles in the polymer will continue to improve. |
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| Last Updated ( Saturday, 14 February 2009 ) |
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