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7 March 2008


RPI student develops polarized LED

Rensselaer Polytechnic Institute in Troy, NY, USA says that Martin Schubert, a doctoral student in electrical, computer, and systems engineering, has developed the first polarized LED, which could enable their widespread use as more efficient light sources for liquid-crystal displays (LCDs, which require polarized light) in TVs, computers, cell phones and cameras.

Picture: Martin Schubert, developer of the polarized LED. (Photo Credit:
Rensselaer/Kris Qua.)

Schubert’s innovation has made him the second recipient of the $30,000 Lemelson-Rensselaer Student Prize. First given in 2007 and funded through a partnership with the Lemelson-MIT Program, the prize is awarded to a Rensselaer senior or graduate student who has created or improved a product or process, applied a technology in a new way, or otherwise demonstrated remarkable inventiveness.

“The Lemelson-Rensselaer Student Prize recognizes our most inspired and dedicated students for their ingenuity and deep understanding of the greater global implications of their innovations,” said Rensselaer president Shirley Ann Jackson. “Schubert is both a talented engineer and inspired entrepreneur.”

Schubert’s polarized LED enables better control of the direction and polarization of the light being emitted. Less energy is wasted producing scattered light, allowing more light to reach the desired location. The polarized LED is hence suited to backlighting LCDs without the polarizers needed with conventional LEDs (which reduce the screen’s light output). Its focused light can produce images on the display that are more colorful, vibrant, and lifelike, with no motion artifacts.

Schubert first discovered that traditional LEDs actually produce polarized light, but existing LEDs did not capitalize on the light’s polarization. He then devised an optics setup around the LED chip to enhance the polarization.

RPI reckons that the invention could advance efforts to combine the power and environmental soundness of LEDs with the clarity of LCDs. Polarized LEDs could replace fluorescent lights (which are less efficient and contain mercury) in TVs and monitors. They could also be used for street lighting, high-contrast imaging, sensing, and free-space optics.

Schubert is the son of lighting research expert and senior chair of the Rensselaer Future Chips Constellation, professor E. Fred Schubert (although received his bachelor’s and master’s degrees from Cornell University in electrical engineering). He has published three peer-reviewed, archival papers and filed for several patent applications on the polarized LEDs, and should complete his doctorate in electrical engineering this fall.

See related item:

LED market returns to double-digit growth in 2007

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