Ormocer-based lighting eliminates peripheral colour effects

Paul Boughton
At nano tech 2010 in Tokyo, Fraunhofer researchers will present some remarkable nanotechnology developments: pin-sharp projections, light that is 'whiter than white' and varnishes that emit sounds in response to temperature changes.
Dr Michael Popall of the Fraunhofer Institute for Silicate Research ISC in Wurzburg, Germany, says: "For a long time, producing white light with no peripheral colour effects was an almost unsolvable technical problem. White light is produced by mixing the complementary colours red, green and blue. Undesirable refraction occurs with conventional beamer technology, resulting in coloured streaks on the periphery of the projection." However, his team has developed a light diode, smaller than a pinhead, that transmits light through thousands of lens structures measuring only a few hundred nanometres in diameter.
This technology – which researchers will present from February 17 to 19 at nano tech 2010 in Tokyo, Hall 3.03 Booth F-14-1 – delivers not only brilliant color, but also pure white. Popall adds: "The tiniest of red, blue and green light diodes on the most condensed space produce the light, which is then bundled and homogenised by the nano-structured Ormocer optics.
"Ormocers are an ideal material for the production of micro-optics. They are not only superior light conductors, but are also easy to process – not as brittle as glass, and not as pliant as polymers." Ormocers are a hybrid of inorganic and organic components that are networked at the molecular level. This material makes it possible to realise things inconceivable even a couple of years ago - such as ultra-flat and ultra-small optics for micro-cameras or beamers that fit into a pocket. The design of the new Ormocer optics was developed by experts at the Fraunhofer Institute for Applied Optics and Precision Engineering (IOF). Popall says: "Thanks to close collaboration among chemists at ISC and the physicists and engineers at IOF, we have succeeded in developing Ormocer tandem arrays with two-sided and symmetrically arranged micro-lens configurations, which allow the light from light diodes to be projected with pinpoint accuracy and without refraction errors." The new technology is said to be almost market-ready.
Another technology to be shown at nano tech 2010 is a new varnish developed by researchers at the Fraunhofer Institute for Engineering and Automation (IPA) that enables surfaces to emit sound if they become warmer or cooler. This is achieved by carbon nano-tubes embedded in the varnish that conducts electricity: if a surface is coated with this varnish, then it can be heated up by passing an electric current. The change in temperature is audible because the warming surface makes the air around it vibrate. Ivica Kolaric, head of department at IPA, comments: "And this is only one of a myriad of conceivable innovative applications. The surface coating is likewise capable of heating large surfaces and surfaces of complex shape and, in the future, conceivably it can be used as a multifunctional coating for heating, or as a resistance sensor, or as a coating for color displays."
For more information, visit www.fraunhofer.de

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