Turn off the lights when you leave.

July 24, 2004 2:57 PM

The end of the light bulb? E. Fred Schubert, a professor at Rensselaer Polytechnic Institute "claims to have invented a 99-percent efficient reflector that promises to speed the replacement of light bulbs with LEDs." According to researchers, this could happen within the next five years. The current prototype is bankrolled by the ARPA and The National Science Foundation "recently award Schubert's team a $210,000 grant to create in three years a commercial version of his patented omnidirectional reflector."

"Schubert claimed that lighting accounts for 25 percent of U.S. electrical energy consumption. Since white LEDs emit more light per dollar and generate less unwanted heat, they are potentially a major energy saver." (see EE Times link)

Meanwhile, some of the oldtimers seem to be pretty refractory.
posted by tcp (10 comments total)

I've been using the flourescent energy saver bulbs for some time, but I'm not really happy with them. Despite the claims, they seem to blow more often than incandescent bulbs, and they also don't work properly in "dimmer" circuits, and take a few minutes to reach full brightness. Looking forward to the LED!

But, I predict a small proportion of the population will continue to use ordinary lightbulbs, simply because it's their right to use all the goddamn energy they want. A bit like this fella. Ah well, their loss.
posted by Jimbob at 3:34 PM on July 24, 2004

This incandescent light bulb just celebrated its 100th year of continuous operation. Top that, LEDs!
posted by laz-e-boy at 3:42 PM on July 24, 2004

There are no white LEDs -- rather, a blue LED is surrounded by a layer of phosophorus that emits white when stimulated with high energy blue photons. This poses two problems for this development team: First, blue LEDs are an only very recently solved problem (they were something of an obsession for this Japanese researcher) and thus the technology is not as well understood -- it's harder to manipulate what you only recently got working at all. And second, they have to adapt a phosphorus layer into a system that presently only needs to retransmit directly emitted photons.

I'm sure they're confident that they'll pull it off, but it's worth us respecting the additional difficulty they face.
posted by effugas at 4:33 PM on July 24, 2004

What are the advantages or disadvantages for LEDs vs. Flourescents?
posted by KirkJobSluder at 4:59 PM on July 24, 2004

Kirk--

Well, to some extent white LEDs are fluorescent -- they're a phosphorus layer being stimulated by blue LEDs. But what we commonly refer to as a fluorescent lamp involves flickering an electrical signal inside a tube at about 3000hz, which is generally beyond the human visual system's ability to resolve as pulses. (This is why power lines make fluorescent tubes glow -- those things exist to glow in response to EMF.) LEDs are continuous stimulation.

Fluorescent tubes are very mature technologies, as they've been adopted wholesale by corporates for monetary savings over incandescents. At the moment, they're also quite a bit more efficient than LED's. But not too many people have tube lighting at home, at least outside their kitchen stove -- the light is pretty harsh. What we've seen lately is tubes wrapped into the shape of standard incandescents, and they've been moderately popular (though they're pretty expensive). The level of brightness they can put out is somewhat limited, though -- while LEDs are slowly beginning to approach halogens for pure dumpage of candlepower, I think fluorescents have mostly tapped out. However, fluorescents are quite a bit cheaper than LEDs -- something partially to do with the fact that semiconductor fabs are quite a bit pricier than what's needed to build the tubes.
posted by effugas at 5:46 PM on July 24, 2004

>However, fluorescents are quite a bit cheaper than LEDs

Well, they *might* be cheaper than white LEDs, a regular red LED runs about 2 - 5 cents in bulk. It's only a matter of time before they are cheaper than dirt. :-D
posted by shepd at 6:53 PM on July 24, 2004

"Light bulbs deserve to die," said Bruce Sterling a while ago. Now start working on the other nine.
posted by thijsk at 6:53 PM on July 24, 2004

This is remarkable, if it comes to fruition. Interesting post!
posted by ParisParamus at 6:57 PM on July 24, 2004

Thanks effugas, I converted much of my indoor lighting to compact flourescent about a year ago, primarily because something about our house wireing results in popping an incadescent about once a month. Also, a nice thing about the CF bulbs is that they run cooler, allowing me to put a brighter bulb into fixtures that would only take a 20-40W incadescent. So I'm a bit curious as to how these compare.
posted by KirkJobSluder at 7:52 PM on July 24, 2004

LEDs vs. the Lightbulb. This is a great article from MIT's Tech Review from last year. They use blue or ultraviolet LED's and phosphor for the white ones.

It's a sunny day on the campus of the University of California, Santa Barbara, but little light penetrates the labs and offices of Shuji Nakamura. Shades sheathe the windows in part because, Nakamura says, "I worry about unknown people around here--that they will include a spy."

That sounds farfetched until you consider that Nakamura, who played a lead role in the development of blue light-emitting materials, is now back for a second act. In the 1990s Nakamura gained fame by cooking up the first semiconductor materials to emit bright blue light--a boon for displays and data storage--and sparked a global race to perfect the materials. He made those trailblazing lasers and their glowing cousins, light-emitting diodes (LEDs), at Tokushima, Japan-based Nichia--and became a sort of national folk hero in the process. (When Nakamura is in Tokyo, subway riders accost him for his autograph.)

Now, having moved to an academic post in the United States, he is at it again--caught up in an intense worldwide competition. That's because the bright blue emitting devices that are the progeny of his original inventions provide a key stepping stone in a high-stakes effort to produce white-light LEDs that are sufficiently cheap, pleasing, and efficient to crush Edison's almighty light bulb--and radically transform the $40 billion general-illumination industry.

posted by euphorb at 9:05 PM on July 24, 2004