Posted on 10/25/2005 1:01:25 PM PDT by PoorMuttly
Accidental Invention Points to End of Light Bulbs
The main light source of the future will almost surely not be a bulb. It might be a table, a wall, or even a fork.
An accidental discovery announced this week has taken LED lighting to a new level, suggesting it could soon offer a cheaper, longer-lasting alternative to the traditional light bulb. The miniature breakthrough adds to a growing trend that is likely to eventually make Thomas Edison's bright invention obsolete.
LEDs are already used in traffic lights, flashlights, and architectural lighting. They are flexible and operate less expensively than traditional lighting.
Happy accident
Michael Bowers, a graduate student at Vanderbilt University, was just trying to make really small quantum dots, which are crystals generally only a few nanometers big. That's less than 1/1000th the width of a human hair.
Quantum dots contain anywhere from 100 to 1,000 electrons. They're easily excited bundles of energy, and the smaller they are, the more excited they get. Each dot in Bower's particular batch was exceptionally small, containing only 33 or 34 pairs of atoms.
When you shine a light on quantum dots or apply electricity to them, they react by producing their own light, normally a bright, vibrant color. But when Bowers shined a laser on his batch of dots, something unexpected happened.
"I was surprised when a white glow covered the table," Bowers said. "The quantum dots were supposed to emit blue light, but instead they were giving off a beautiful white glow."
Then Bowers and another student got the idea to stir the dots into polyurethane and coat a blue LED light bulb with the mix. The lumpy bulb wasn't pretty, but it produced white light similar to a regular light bulb.
White light from Bowers' lumpy new bulb. Credit: Vanderbilt University
The new device gives off a warm, yellowish-white light that shines twice as bright and lasts 50 times longer than the standard 60 watt light bulb.
This work is published online in the Oct. 18 edition of the Journal of the American Chemical Society.
Better than bulbs
Until the last decade, LEDs could only produce green, red, and yellow light, which limited their use. Then came blue LEDs, which have since been altered to emit white light with a light-blue hue.
LEDs produce twice as much light as a regular 60 watt bulb and burn for over 50,000 hours. The Department of Energy estimates LED lighting could reduce U.S. energy consumption for lighting by 29 percent by 2025. LEDs don't emit much heat, so they're also more energy efficient. And they're much harder to break.
Other scientists have said they expect LEDs to eventually replace standard incandescent bulbs as well as fluorescent and sodium vapor lights.
If the new process can be developed into commercial production, light won't come just from newfangled bulbs. Quantum dot mixtures could be painted on just about anything and electrically excited to produce a rainbow of colors, including white.
One big question remains: When a brilliant idea pops into your mind in the future, what will appear over your head?
I always wanted to be The Muttly in the Gray Flannel Suit....and perhaps this will be the way.
No really.
My boss, looking over my shoulder, ready to steal my idea.
Sounds like my five kids.
I knew this would be an highly technical and scientific thread.
I just knew.
Accidental Invention (yada yada)
Posted by Nasty McPhilthy
On News/Activism 10/23/2005 1:11:40 AM PDT · 35 replies · 1,498+ views
For those you gotta ping Squantos and Eaker. :)
Oops my bad, posted 3 days ago, but it was old news even then.
I was reading this the other day in a blog, and meant to post about it. It is a facinating concept, though the article I read went on to fantasy land in the way of efficency...
While the LED lightbulb will be interesting, and save us money, it is the other uses that intrigues me. Fabric coated in mini-emiters able to change colors with a flick of a switch - or perhaps Nike T-Shirts that run the day's commercials across your back.
Science fiction becomes reality, once again.
I was considering that, but Squantos is not feeling well...and I'm afraid of Eaker....
GE and Big Oil will probably team up now to assassinate the inventor. ;)
old news...ah...like fine wine......
Good reason to keep up my relationship with RPI and the Lighting Research Center (Troy, NY)
Any time. (BTW, I am an ME, though I've never worked in the field)
Without knowing that, what's to get excited about?
Don't worry. Wasn't old to me and I appreciated finding it.
"Is it me? or does this material need a source of light or electricity?
How does that differ from fluorescents? How much more efficient is the process?"
The LED is the source of light, the coating only ampliphies and converts it to white light. At least that's my take on it.
Yes there is a source of electricity and light, in the case of the "lumpy" coated blue led bulb, that's obvious.
The point of the invention is that LED's are flexible and easy to manufacture, but not necessarily conducive to a warm colored mostly white light.
When they talk about glowing tables or ceilings, I think they are envisioning covering the surface with a matrix of LEDs and then coating it with a semi transparent polymer embedded with these crystals. Ultimately though, the LED's would have to be connected to a power source.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.