Posted on 12/06/2004 4:01:25 PM PST by nickcarraway
How many engineers does it take to permanently unscrew a light bulb? At San Jose's Lumileds Lighting, the answer is hundreds.
Lumileds, a joint venture of Agilent and Philips Electronics, makes semiconductor chips known as light-emitting diodes. LEDs are found everywhere, from the tiny flashes on digital cameras to the blue lights that illuminate the Arc d' Triomphe in Paris at night. And if all goes right, Lumileds will one day see its LEDs replace the common light bulb.
(Excerpt) Read more at mercurynews.com ...
I saw a tail lens for a high end German car in a test lab recently that used a bunch of LEDs. Not only was the output much brighter, but it was more directional and required much smaller wires to provide a given amount of light.
Traditional incandenscent lights waste about 2/3 of their energy in the form of heat. LEDs waste about 1/20th.
Auto manufacturers see the light. By reducing wasted power, they can run smaller wires, they can use a smaller alternator, and ultimately spend less money. Also, LEDs last a LOT longer than a light bulb.
It's all the rage here in Canada this Christmas. Got a few if 'em myself.
Photoflash on digital cameras is still a xenon discharge tube, IIRC. And as far as LED lighting sources - there are two questions: cost (close to 15$/watt even at discount/surplus places; equivalent to paying, say, 1-1.5$/W for an incandescent bulb of equal output) and the spectrum of "white" emitted light - it is not continuous, like with incandescents, but more in the nature of fluorescent lamps (with prominent green) or of sodium discharge lamps (yellow).
So what will my daughter use in her Easy Bake oven if incandescent lamps are replaced with LEDs?
My reading light is a cluster of 50 LEDs in a PAR-20 format. It is brighter than the 50W spot it replaces, cost me $24, and runs on about 8W. Expected life is 50,000 hours.
I also have a flashlight that uses one of Lumiled's Luxeon LEDs and it is brighter than the MiniMag it replaced; cheaper to operate as well.
I have a few LED nightlights and have replaced several interior lights in my car with long-life high brighness LEDs.
I think LEDs or something like them will be pretty common soon, once folks see the economies involved.
The Luxeon has a nice warm white look, but the reading light has Nichia LEDs that, while bright, have a cool output (tending toward blue-white). Oh yeah, my reading light bulb stays cool while operating, not at all like an incandescent.
The unnatural light of flouresants is horrid. Full spectrum lighting is the only way to go.
Neither do LEDs. Look at stoplights (most are LED in my area) and there is no flicker.
"Neither do LEDs. Look at stoplights (most are LED in my area) and there is no flicker."
Actually some circuits do "strobe" the LEDs to save energy. It is much higher frequency than 60 cycles, but many times you can notice the a strobe effect in some LED panel indicators. One would hope that a LED replacement bulb would not be strobed.
This stuff isn't really new. Lumex has been replacing incandescent lamps with super bright LEDs for some time now. They've recently split off the high output products to Sunbrite LEDs.
Many of the traffic lights in the Chicago area are LEDs these days and LEDs have appeared as tail lights and third brake lights for a few years already.
LEDs are great for all sorts of reasons, but one must consider that they do use some materials that aren't nearly as plentiful as the meterials used in incandescent lighting. As well, many of those materials are highly toxic, although they are well sealed.
The only application I've seen where I've preferred incandescents to LED's is in automobile tail lights. That flicker drives me nuts. It's okay if your eyes are still; then you don't see the flicker. But when you shift your gaze, the LED tail lights leave a chopped-up (rather than smooth, like incandescents) trail of after-images that's really distracting.
Imagine the power that could be saved in buildings and homes. Not only would you save the excess power needed to light buildings, but you would save on airconditioning to remove the excess heat.
You'll find them as aftermarket motorcycle parts as well.
Although I don't know if they're actually DOT certified, meaning "street legal."
Mark
Also, the lights go on the instant the pedal is pushed whereas regular bulbs take long since the filament has to heat up. Since the brake lights come on faster, in theory the number of rear end accidents should decline.
"Neither do LEDs. Look at stoplights (most are LED in my area) and there is no flicker."
Check again. The higher power LEDs used for singage and most automotive talilights are usually pulsed. If you ran them continuously, they would burn out and believe it or not, they would emit some heat as they toasted themselves to death.
You may not notice the pulsing directly, but if you move your eyes past the light, you will see the pulsing. They are set to pulse a bit faster than your normal persistance of vision will notice.
I see 'em around here pretty regularly as taillights. Was noticing a pair this morning as I was stuck behind a FedEx truck.
MM
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