Researchers from Korea claim to have produced the world's first purely white LED (light-emitting diode).
Soo-Young Park, a professor of organic materials for photonics at the Department of Materials Science and Engineering at Seoul National University in Korea, led the group, which includes researchers from the University of Valencia in Spain.
LEDs are much more energy-efficient than incandescent or compact fluorescent lightng (CFL), but the quality of light they can give a room is up for debate.
Soo-Young Park, professor at Seoul National University.
(Credit: Seoul National University)Because LEDs do not naturally produce white light, getting them to look like they do adds to their production cost, making them much more expensive than your average incandescent or CFL. Many companies have been trying to come up with different LED recipes and components to produce a nice white light, while keeping the consumer cost down.
Park and his group claim to have engineered a molecule with one orange and one blue light-emitting material that produces a white light in the visible light spectrum when put together.
In other words, they say they've invented a white-light-emitting diode.
Repeated laboratory tests apparently showed that the new form of LED molecule is efficient, color stable, and able to be reproduced again and again, making it a legitimate candidate for use in LED lighting.
A detailed explanation of the group's molecular work can be found in the current issue of Journal of the American Chemical Society.
"An ideal material for a white-light source should be cost-effective, stable, robust, emit over the whole visible spectrum, not suffer from self-absorption, and its pure color should be easily reproducible. With this goal in mind, we have successfully synthesized and characterized, for the first time, a white-light-emitting single molecule dyad, consisting of two noninteracting chromophores showing excited-state intramolecular proton transfer," Park and his group said in their paper.
Here is a mock-up of the EyeStop bus shelter.
(Credit: MIT Senseable City Lab)High-tech bus stops so cool they might actually entice you to take a ride will be installed next year in Florence, Italy.
The urban fixtures have been designed by a group of researchers led by Carlo Ratti, head of the Senseable City Lab at the Massachusetts Institute of Technology.
The EyeStop is a touch-screen bus shelter that monitors environmental conditions and real-time bus movement and also provides information and communication tools that can interact with your cell phone.
The EyeStop, which has touch sensitive e-Ink screens as well as LEDs, features a bus map plotting locations in real-time, e-mail and Web access, tools for planning a best route and getting directions, a community bulletin board, and, of course, a place for silent video advertisements. It will also use sensors to monitor and display local air quality.
Riders can choose to have their local EyeStop bus stop sync with their cell phone. The EyeStop you normally frequent, for example, could twitter you that your usual bus is running late that morning.
Intended for tourists as well as locals, the EyeStop tools will be accessible in several languages.
About 1,000 EyeStop bus poles will be installed in Florence, Italy, in 2010.
(Credit: MIT Senseable City Lab)A bus pole version of the EyeStop with similar mapping, info, and communication tools will also be introduced. It glows brighter as the next bus nears the stop to signal pedestrians from afar.
The design for the EyeStop was unveiled this week at the Genio Fiorentino festival in Florence, and a prototype will soon follow.
Florence residents will start testing the high-tech bus stop's usefulness, durability, and limitations in October. Following that, about 200 bus shelters and 1,000 bus poles are expected to be installed next year. The EyeStop was developed by Ratti's project team, in collaborartion with the Province of Florence and Florence's local transportation authority.
The bus shelter and bus pole versions of the EyeStop will power themselves with solar energy, but they won't be one-size-fits-all.
Each EyeStop will be customized by a computer program that takes into account the stop's immediate surroundings. As a result, each can be built to fit into the existing space using steel, glass, and gray stone local to Florence. The software also considers maximum sunlight exposure for the location to determine power generation needs.
But is it graffiti proof?
"We have looked into special glass surfaces that are self-cleaning and graffiti proof," Ratti said in an e-mail. "However, we will perform some real tests before building the prototype in October."
This is EyeStop bus shelter with an imaginary user.
(Credit: MIT Senseable City Lab)
LED manufacturer Cree has been awarded a contract from the U.S. Department of Defense to supply over 4,200 recessed LED lights for the Pentagon, the company announced Tuesday. Financial details were not disclosed.
Testing commissioned by the U.S. government determined that Cree's LR24 recessed LED lights would offer a 22 percent energy reduction compared with fluorescent lights, and save the Pentagon 140 tons of carbon dioxide emissions per year.
The government also commissioned a cost analysis that showed the lights would yield a payback of less than four years once things like energy savings, maintenance, and the expense of properly disposing mercury-laden fluorescent bulbs were taken into account, according to Cree.
The new lighting will be installed in Wedge 5 of the Pentagon, coinciding with the major Pentagon renovation already under way in that area.
The purchase also happens to follow the advice of the American Recovery and Reinvestment Plan recently proposed by President-elect Barack Obama in his January 3 address.
As part of his plan to reduce reliance on foreign oil and create more jobs, President-elect Obama has suggested that the government will "renovate public buildings to make them more energy efficient."
Analysts have predicted that LED lighting will replace incandescent bulbs, making LED lighting manufacturers a bright spot to watch for within the struggling tech industry.
Before: A Pentagon room before Cree's LED lights were installed.
(Credit: Cree)
After: The same room at the Pentagon after Cree's LED lights were installed.
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