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The End Of The Light Bulb?
sdmonroe wrote to mention an MSNBC article discussing the likely eventual replacement of common light bulbs by LEDs. That replacement is likely to come quicker thanks to an accidental discovery announced this week. From the article: "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. ... 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.'"
I have been impressed with the LED lights over florescent or incandescent. The subdued lighting is fine with me and the energy consumption / bulb longevity is the best part. When my wife and I move (build a house), we will go 100% LED.
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White LEDs are already 3 times as efficient as mercury fluorescent, and fluorescent tubes are 3 times as efficient as incandescent. They (fluorscent and LEDs) can get pretty good colour accuracy, too, if they want to. The only thing holding them back is price. I'm not sure what this new invention might bring to the table in that regard.
Have you ever tried an LED light? They suck!!! They do not cast nearly enough light. The light color is a disturbing and unnatural color, usually with too much blue in it.
Florescent tubes are FAR superior to LED lights and yet so many people prefer good old incandescent lights to even florescent tubes. Hell, even something as simple as a flash light. Try an LED flash light and then try a xenon Mag Light and tell me which one rocks your socks.
LED lighting is one of those technology "revolutions" that are for the sake of technology. They are NOT better.
at my workplace, a hotel on the beach.
We had for many years yellow colored standard bulbs, as they don't attract bugs.
we started replacement with yello fluro twist bulbs, to save on electricity and replacement costs.
in research, it turns out, we can use white fluro-- as they only emit light in a very narrow spectrum of white light, unlike an ordinary filament bulb.. and the range they do emit light on, suitable for humans, does not attract bugs.
I'd guess these low power led lights also emit white light on a very narrow band....
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If the manufacturing breakthough talked about in this article pans out, the cost of Quantum Dot manufacture will drop from $2,000 to $400 per gram. That's huge improvement, but I still wouldn't expect to see Quantum Dot lightbulbs on ThinkGeek anytime soon...
I have an led flashlight.
led's emit a very cold light. Fourescent light is described as cold and "vitamin burning", but led light is even worse in this respect.
It works for headlights, emergency beacons, and select areas, but generalized room lighting is not one of those areas.
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Anyone who tries (like me) to build small lighting devices with LEDs rapidly discovers lots of practical difficulties. To equal the light output of one cheapo fluorescent tube you need hundreds of the little blighters. It is not easy to make their output look even, rather than dotty. And with that large number, reliability is a real problem. Even a 1% failure rate (amplified to 3% or 5% by the LEDs often being in series) rapidly translates into major unevenness. Even production lines struggle to make large arrays of LEDs stay 100% alight, but little people often get sold the bin ends, which fail rapidly in service.
Also LEDs are NOT yet more efficient than fluorescents. Their data sheets never give the one number that really matters: what percentage of input energy actually emerges as light? The answer is usually frighteningly low. Therefore LED devices tend to cook themselves to death if run really bright.
To run LEDs stably requires either a wasteful series resistor or an expensive semiconductor constant-current device. And cheap low-voltage power supplies are actually badly life-limited by their electrolytic capacitors. In my experience many LEDs die prematurely because of a failing power supply and hot sunshine.
Don't get me wrong. LEDs are the future, but you must be wary of calling them energy-saving, long-lasting, or easy to use!
(I hate scientifically-illiterate journalists.)
Time is Nature's way of keeping everything from happening at once... the bitch.
AC has it's advantages, especially for long distance transmission. But in a house, it's gradually losing out. If you don't count lightbulbs, I'd say I have more DC things plugged in than AC. So many of the outlets are connected to "bricks" or "wall warts" to change the high voltage AC to low voltage DC. Things that don't have an exterior brick, like the DVD player or TiVo just do the conversion internally. While the higher voltage AC might have some benefits of lower loss in the wires, I'd think that umpteen separate transformers and rectifiers are negating a large percentage of that benefit.
If lighting were go to DC, then a re-think of the home wiring would really be in order. If there were a "standard" DC voltage and current available to lower power devices, we might not have wall transformers with anything from 3v-12v hanging off our surge supressors.
So in-house DC makes lots of sense. Send the AC to things like ovens and clothes dryers, and DC to most everything else.
I know what you mean though. I do hate the way they look. The orange glow even makes trees look creepy.