- ALBUQUERQUE, N.M.
- A revolution is quietly occurring that promises to change the way we
light our homes, offices, and world. Sandia National Laboratories is among
the research entities around the country at the forefront of the revolution.
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- Some 25 Sandia researchers are working on an project
that will establish the fundamental science and technology base to replace
the country's primary lighting source, incandescent bulbs and fluorescent
tubes, with semiconductor light-emitting diodes (LEDs) - solid state lighting.
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- Sandia Senior Scientist James Gee, together with department
managers Jerry Simmons and Bob Biefeld, head up the project.
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- "In some ways the revolution in lighting can be
compared to the revolution in electronics that began 50 years ago and is
only now reaching maturity," Gee says. "Just as for electronics,
glass bulbs and vacuum tubes are giving way to semiconductors. And as in
the microelectronics revolution, many of the possible applications for
solid-state lighting will occur in ways that have not yet been envisioned."
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- LEDs are already found in toys, electronics, traffic
lights, automobile signals, and large outdoor displays - devices that require
durability, compactness, and cool operation. In some applications they
also enable significant cost savings due to their lower consumption of
energy: LED-based red traffic lights, for example, consume one-tenth the
energy of their incandescent counterparts, enabling them to pay for themselves
in as little as one year.
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- As LED technology matures, revolution leaders expect
solid-state lighting to also rapidly outdistance conventional lighting
sources in both performance and cost.
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- "This new white light source could change the way
we live, and the way we consume energy," says Simmons, who manages
the project. "LEDs could be 10 times more efficient than incandescent
bulbs and two times more efficient than fluorescents. Clearly, LEDs' replacement
of conventional light sources would significantly reduce worldwide energy
consumption."
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- Lighting is presently responsible for roughly 20 percent
of electricity consumption. Researchers believe that the development and
adoption of solid state lighting technology could reduce the nation's electrical
consumption by 10 percent.
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- LEDs were first demonstrated in 1962 by General Electric.
The first products were introduced in 1968 - indicator lamps by Monsanto
and an electronic display by Hewlett-Packard. However, LEDs were limited
to small-signal applications until 1985 when LED power was increased, resulting
in new applications. In 1993 researchers at several universities in the
US and Japan developed a fairly efficient blue light LED based on gallium
nitride. Efficiency improvements followed quickly. Today, energy-efficient
LEDs are available from red to green to blue light, making it possible
to generate white light for illumination.
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- However, Gee says, LED-based light sources are expensive
- more than two orders of magnitude more expensive than commercial incandescent
light bulbs - and will not be practical until their costs are reduced and
efficiency is further increased.
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- As part of the LEDsproject, some 25 Sandia researchers
are exploring ways to do exactly that - make LEDs more efficient and less
costly. They are working on the fundamental science and technology challenges
where Sandia has unique capabilities. Among those challenges are:
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- * Developing an improved understanding of the physics
of the gallium nitride-based materials that are the base materials of the
LEDs.
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- * Improving optoelectronic devices and materials for
abundant photon generation and high light extraction efficiency.
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- * Improving wavelength conversion and color mixing technologies
for generation of white light. Improving packaging technologies for high-power
LEDs.
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- Numerous industrial companies, as well as universities,
are working to develop technologies for solid state lighting. However,
Biefeld says, "in many respects Sandia is unique, due to our extensive
capabilities in semiconductor growth and processing, reactor modeling,
and experimental and theoretical materials physics, all located at a single
institution."
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- "These are exciting challenges that will engage
our scientists over the next several years," Gee says. "Our work
will position Sandia to become a leading developer of the science and technology
for this revolution in lighting."
-
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- Sandia is a multiprogram laboratory operated by Sandia
Corporation, a Lockheed Martin company, for the U.S. Department of Energy.
With main facilities in Albuquerque, N.M., and Livermore, Calif., Sandia
has major R&D responsibilities in national security, energy and environmental
technologies, and economic competitiveness.
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- Editor's Note: The original news release can be found
at http://www.sandia.gov/media/NewsRel/NR2002/LEDSrelease1.htm
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- Note: This story has been adapted from a news release
issued by Sandia National Laboratories for journalists and other members
of the public. If you wish to quote from any part of this story, please
credit Sandia National Laboratories as the original source. You may also
wish to include the following link in any citation: http://www.sciencedaily.com/releases/2002/04/020417070346.htm
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