Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Enhanced LEDs Promise To Transform Lighting

23.07.2004


A research team at Rensselaer Polytechnic Institute has created a new type of reflector that has dramatically improved LED (light-emitting diodes) luminance. The National Science Foundation (NSF) recently awarded the research team a three-year, $210,000 grant to move the patented omni-directional reflector to market.



“We have developed an omni-directional reflector (ODR) for LEDs that will accelerate the replacement of conventional lighting used for a multitude of applications, such as lighting in homes, businesses, museums, airports, and on streets,” said Fred Schubert, Wellfleet Senior Constellation Professor of the Future Chips Constellation at Rensselaer who is heading the research effort. “The advance has implications ranging from major energy savings to contributing to a better environment and improving health.”

New LED Technology


LEDs are made from semiconductor “chips,” the size of sand grains, covered with arrays of pencil-eraser size plastic bulbs. Increasingly being used in traffic signals, automotive lighting, and exit signs, LEDs have the potential to use far less electricity and last much longer than conventional fluorescent and incandescent bulbs. But current LEDs are not bright enough to replace most everyday uses of the standard light bulb.

“Only when the light generated is efficiently reflected inside the semiconductor can the brightness exceed that of standard lighting sources,” Schubert says. “With the ODR, which reflects light at nearly 100 percent—up to twice as much as previous reflectors—we now have an LED that could revolutionize today’s standard lighting.”

The ODR is a thin triple-layer coating that consists of a semiconductor, a dielectric material, and a silver layer. Reports of the new reflector were published in the May 31, 2004, issue of the journal of Applied Physics Letters and last October in the IEEE (Institute of Electrical and Electronics Engineers) journal of Electron Devices Letters. In addition to NSF funding, the researchers also have received $250,000 in the last two years from the Defense Advanced Research Projects Agency to develop the new reflector.

Next-Generation LEDs: Cutting Energy Costs and Potential Medical Applications
Next-generation LEDs are expected to become the widespread “green technology” of choice for lighting, Schubert says.

“With near ideal LEDs, our nation could cut electricity consumption for lighting in half,” Schubert says. “Lighting is the most common use of electrical energy, taking up about 25 percent of electrical energy consumption in the United States.”

Schubert also notes that LEDs are mercury-free, unlike even the newest energy-saving fluorescent bulbs. Mercury exposure can cause significant health problems in children and adults, according to National Institutes of Health.

In addition, an LED that emits higher-quality light has potential medical applications, such as alleviating sleep disorders, Schubert says. The circadian cycle, the 24-hour sleep-wake cycle in healthy humans, is controlled by the spectrum and intensity of light sources. Using the right light for the right time of day can enhance or hinder sleep.

For example, “tunable” light sources, such as LEDs, which emit longer wavelength light (red) that mimics the setting Sun could help those with insomnia sleep better. Individuals are not affected visually by the difference in “colored” light, but the body’s internal clock can sense the difference, Schubert says. Conventional illumination sources cannot provide the same benefit because of the lack of “tunability,” meaning their optical spectrum cannot be adjusted to emphasize various wavelengths.

Schubert, who won the 2000 Discover Magazine Award for his photon-recycling semiconductor LED invention, has helped to transform traffic signals and airport runway lighting through his numerous LED-based inventions. He holds appointments in the Department of Electrical, Computer, and Systems Engineering and in the Department of Physics, Applied Physics, and Astronomy at Rensselaer. The recently-completed Future Chips Constellation, in which he is a senior professor, focuses on innovations in materials and devices, in solid state and smart lighting, and extends to applications such as sensing, communications, and biotechnology.

| newswise
Further information:
http://www.rpi.edu

More articles from Power and Electrical Engineering:

nachricht Open, flexible assembly platform for optical systems
24.01.2017 | Fraunhofer-Institut für Produktionstechnologie IPT

nachricht A big nano boost for solar cells
18.01.2017 | Kyoto University and Osaka Gas effort doubles current efficiencies

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Scientists spin artificial silk from whey protein

X-ray study throws light on key process for production

A Swedish-German team of researchers has cleared up a key process for the artificial production of silk. With the help of the intense X-rays from DESY's...

Im Focus: Quantum optical sensor for the first time tested in space – with a laser system from Berlin

For the first time ever, a cloud of ultra-cold atoms has been successfully created in space on board of a sounding rocket. The MAIUS mission demonstrates that quantum optical sensors can be operated even in harsh environments like space – a prerequi-site for finding answers to the most challenging questions of fundamental physics and an important innovation driver for everyday applications.

According to Albert Einstein's Equivalence Principle, all bodies are accelerated at the same rate by the Earth's gravity, regardless of their properties. This...

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Breaking the optical bandwidth record of stable pulsed lasers

24.01.2017 | Physics and Astronomy

Choreographing the microRNA-target dance

24.01.2017 | Life Sciences

Spanish scientists create a 3-D bioprinter to print human skin

24.01.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>