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 Researchers pave the way for ionotronic nanodevices
23.02.2017 | Aalto University

nachricht Microhotplates for a smart gas sensor
22.02.2017 | Toyohashi University of Technology

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: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>