By John DeFore
Last week, students around the nation were busy working on suntans and sleeping off hangovers. Not Martin Schubert, though, who spent Spring Break in the lab — despite having just landed a $30,000 prize that would have bought an awful lot
of daiquiris.
Schubert, a doctoral student at Rensselaer Polytechnic Institute, was awarded the Lemelson-Rensselaer Prize for his work with light emitting diodes (LEDs), which are already a fruitful alternative for some energy-efficient lighting applications. Now, thanks to Schubert, they hold even more promise.
Schubert has discovered how to use LEDs to produce polarized light instead of the non-polarized light emitted by today’s LEDs. That opens up the range of devices in which LEDs can be used — including, most notably, the liquid-crystal display (LCD) screens found in everything from big-screen TVs to cell phones.
“The operation of LCDs is based upon the polarization of light,” the researcher explains. “Only one polarization of light is used - you can verify this by looking at an LCD through polarized sunglasses and tilting your head. When unpolarized lights such as conventional LEDs or fluorescent lights are used in backlights, up to half of light produced is wasted. For an ideal LED that emits completely polarized light, there would be no waste.”
Presently, Schubert continues, “fluorescent lights are used in virtually all LCDs, with a few exceptions, such as a few high-end LCD TVs, and some ultra-thin laptops such as Apple’s Macbook Air.” Like the compact fluorescents that are being adopted for home use, these tiny light sources “contain toxic mercury, which makes proper disposal difficult.”
Switching today’s fluorescent backlights out with even unpolarized LEDs would avoid the toxicity problem while lowering energy use. But using polarized LEDs would go even farther: Schubert claims that “power consumption could be reduced by 75 percent.”
The invention isn’t quite ready for commercialization — “our LEDs don’t emit perfectly polarized light yet,” he admits, “but they are a step in the right direction.”
Copyright © 2008 | Distributed by Noofangle Media









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