We've written a lot about LEDs as the future of bright green lighting. But the LED's prospects are looking brighter and brighter, it would appear:
If a time traveler from a hundred years ago were to visit a home today, much of the technology would be completely alien. The television, cordless phone and computer would probably leave him flabbergasted. But on seeing a light bulb, he might say, "Ah! Here's something I recognize. A few of those grace my home, too."
If the visitor comes back in 15 years, the fruit of Thomas Edison's bright idea may be gone. The likely replacement: light-emitting diodes, or LEDs.
Indeed, the buzz on LEDs is spreading through the facility management industry, while innovations (like LED floodlights) are spreading. I suspect that the future may indeed bask in diode-emitted light...
I recently ran a research project at the University of Montreal's design school looking at LED-based lighting. The general prognosis in the industry is that mass-market lighting will be coming onstream in roughly five years, especially since there will be a snowball effect.
Unfortunately, most manufacturers are not pushing the technology, since there is no standard for any 'bulb' equivalent, and the bulb industry is a surprisingly large lobby group.
Perhaps the most interesting thing we discovered is how little is known about the effects of intense, narrow-spectrum light. We do, after all, absorb some wavelengths of light; some near-IR frequencies have been used for accelerating wound healing in certain clinical trials (see, e.g. Quantum Devices ).
This will have both positive and negative implications, which will in large part depend on the nature of the deployment of yet another technological solution in which we get to be the subjects of a large-scale laboratory experiment! Not unlike the chemical stew we are generating with industrial and pharmaceutical runoff in the water and food streams... Light sources are linked to well-being, via a number of different biological mechanisms, and LEDs offer more spectrum control than any previous light source.
I believe there have been other links to it, but the solid state lighting section of the Lighting Research Institute has comparatively sound information.
All the best,
Check out TIRs launch of lexel at lightfair. full market LEDs are on their way: http://tirsys.com/
I've converted most of my house to compact fluorescent bulbs, but my major concern about them is the mercury they contain. I'm going to guess that the vast majority of people who buy compact's don't even know that mercury is in them, and when they burn out they just throw them in the trash, and when they break, they probably don't take precautions against getting it on/in themselves. This is another reason I welcome the approach of consumer-affordable/usable LEDs.
I'm active in adventure racing, and I'm seeing LED head- and bike-lamps making huge strides in brightness, power consumption and price: every few months a new product comes out which blows away the previous best-of-breed. I've hardly used my incandescent lights in the last twelve months. I think, though, that the real challenge for broad acceptability, as with flourescent, is in developing lights which offer the same visual warmth as incandescent. This may be just a matter of putting a yellow pearl shell around a bunch of LEDs, but it makes a real difference to me: I find my "white" LED lamps are just too blue for comfort.
diyaudio, back when the diy video projector craze hit, was seriously investigating LED's for illumination. but high pressure metal halide systems were way more efficient. this was three years ago now, but led's were 1/4 as energy:light efficient as almost any old high prressure arc light. a lot of new projectors run 200 watt bulbs which put out 2000 lumen even though some obscene contrast ratios: you just cant top efficiency like that.
are led's better than incandescent? oh god yes. but they've only recently managed to get significantly better than fluorescent. the main advantage of LED's is packaging, durability and manufacturing costs.
Actually, LEDs aren't 'better' than fluorescent at all; the lumens per watt (for white light) is about equal to incandescent or halogen, at best, and not nearly equal to fluorescent. Their advantages are in the efficient generation of colored light, small form factor, imperviousness to environmental conditions, long lifespan, and (maybe most importantly) the potential for future efficiencies. Halogen and incandescent, like fluorescent and HID, are near the top of even theoretical efficiencies in terms of lumens/watt; LEDs will almost certainly outstrip them all in the long run.
Key disadvantages include the lack of standards, the lack of knowledgeable installers (you have to be a bit of an engineer to make the things work, unless you buy expensive off-the-shelf products), the lack of a waste management stream (possibly a worse problem than other lights, since often the LEDs are built right into the fixures), and the difficulty of getting a white light with a decent color rendering index; they tend to be a little cold, with odd blue and green overtones.
LEDs are certainly the ones to watch--but I still think it will be around 5 years before they hit the mainstream. They'll have lots of momentum by the time they hit, though.
"Just this week, researchers at the Lighting Research Center at Rensselaer Polytechnic Institute in Troy, N.Y., said they had boosted the light output per watt of a white LED to almost six times that of an incandescent light bulb, beating even a compact fluorescent bulb in efficiency."
oops my link is the same story in a different place :blush: