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DOE Shines $21M on Advanced Lighting Research
coondoggie writes to mention that the US Department of Energy is planning to fork over close to $21 million for 13 projects promising to advance solid-state lighting research and development. "SSL lighting is an advanced technology that creates light with considerably less heat than incandescent and fluorescent lamps, allowing for increased energy efficiency. Unlike incandescent and fluorescent bulbs, SSL uses a semi-conducting material to convert electricity directly into light, which maximizes the light's energy efficiency, the DOE said in a release. Solid-state lighting encompasses a variety of light-producing semi-conductor devices, including light-emitting diodes (LEDs) and organic light-emitting diodes (OLEDs). "
OK, so the light is encrypted?
One would think that the government would encourage energy saving by ensuring cities weren't shining so much light up at the sky where it hardly does any good. I mean, just see Mizon's Light Pollution about not only how it has ruined astronomy, but how it's simply wasteful as well. But I imagine the energy lobby, who continues to fool the public into thinking that the more light street lamps produce the better, maintains its influence.
I thought about this the last time I was flying across the country at night. "Why am *I*, at almost six miles up, able to see all these street lights and parking lots and malls and houses? What a waste of energy."
Seriously, we need to think about our light placement and usage.
There's even studies that show a lot of lighting does NOT deter crime. All it does is let the crook see what he's doing.
Where do I buy them now?
Do they fit into my regular sockets, including BR30 form factors?
Will they give me at least as much focused light?
How much do they cost?
How long do they last?
How much better than fluorescents?
Are they dimmable?
Are they protected against lightening strikes near by?
What toxic materials do they contain?
Will they let me adjust for the color balance I desire (a highly desirable feature)?
Who is exploited in their manufacture, and which country is getting all my money from them?
Going to a new lightening system is seldom as simple as unscrewing one and screwing in another. Many trade-offs exist.
"It's the height of ridiculousness to say for those 9 lines you get hundreds of millions."
There are also studies linking light pollution to increases in breast cancer. On the face of it, might seem a little whacky, but basically the theory is, light at night causes decreased endogenous melatonin production (it doesn't take much light to cause a significant drop in melatonin production) Melatonin is a strong anti-oxidant that they theorize helps keep breast cancer in check. Anyway, that's the current theory to explain the studies.
The best flourescent out there gets roughly 70 lumens per watt. LED's have already passed the 100 lumens per watt barrier.
LEDs are far more efficient than incandescent. I have an LED/incandescent flashlight that lasts far longer in LED mode than incandescent mode but is not quite as bright. ie. Led brightness * LED time far greater than incandescent brightness * incandescent time.
Engineering is the art of compromise.
LEDs might have heavy metals in them but this is well encapsulated and amortized over a far longer lifetime (100k hours vs 10k hours).
Engineering is the art of compromise.
Interesting. Do you have any references for properly lighting your home for maximum crime deterrence?
I have a streetlight right in front of my house, but have still had a couple minor criminal incidents.
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Hmm... if you have trichromatic light of wavelengths 570nm, 540nm, and 430nm shining on an object that absorbs everything except 550nm, then the object will appear black won't it? Whereas if true white light were shining on it, it would reflect the 550nm wavelengths and our eye would interpret that as... yellow or something. Is that wrong?
*White* LEDs don't work that way. You might assume that white LEDs are simply three (or more) normal LEDs combined in a single package. While it is possible to make white LEDs this way, it's not the method usually used (for several reasons, including "color integrity").
Instead, white LEDs are typically made by coating a BLUE indium-gallium-nitride (InGaN) LED with phosphorous. This is not all that different from a fluorescent bulb, which is what the GP postulated.
Different color temperatures can be achieved by varying the phosphorous coverage. Lower coverage lets more blue through (cooler temperature), whereas higher coverage causes more blue to be absorbed and thus more of the phosphorous emission spectrum to be emitted. The dominant line in the most commonly used phosphorous for LEDs is around 580nm (yellow).
It's also possible to get white LEDs that are made by coating a near ultra-violet LED with phosphorous (thus getting even closer to the fluorescent bulb of the GP).
This might change in the future, with serious work being conducted in the field to improve on reliability, efficiency and color characteristics. To the best of my knowledge, however, none of the new methods (go search for yourself) are commercially available and as we all know, many things that seem promising in the lab never make it to market for any number of reasons.
For reference, red diodes emit at ~ 630nm, blue diodes at 470nm, green at 530nm. The exact wavelength of the emitted light depends on the materials used in the LED, of course.