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LED Evolution Could Spell The End For Bulbs
An anonymous reader writes "USA Today is running a story discussing how LED lamps were unthinkable until the technology cleared a major hurdle just a dozen years ago. Since then, LEDs have evolved quickly and are being adapted for many uses, including pool illumination and reading lights, as evidenced at the Lightfair trade show here this week. More widespread use could lead to big energy savings and a minor revolution in the way we think about lighting."
I think one of the main issues with LED lights is the incompatibility with existing lamps.
Sure you buy new lamps every once in a while, but a real breakthrough will come when you can get LED 'bulbs' that fit in a normal 220/110V socket on a normal lamp.
The same thing happened with those energy-saving bulbs, it seems they only really took off (at least here in Denmark where electricity is expensive) when they became available in versions that looked like normal bulbs and fit most lamps.
Another example is the wire spot halogen lights, once they became available in 220/110V versions they took off. Nobody seemed to want those bulky 220->12V transformers around.
Ugh. Blue LEDs are, without a doubt, the most annoying new fad in consumer gadgetry. The problem is they're suddenly showing up in everything, replacing green LEDs as the default.
A couple of months ago I bought an all-in-one VCR/DVD deck that plays and records to both tapes and DVDs. Hell of a convenient unit, except that when you power this puppy up, it has four blue LEDs on its face. One for "power on," one for "disc in," one for "tape in," and one down by the controls which I guess is there for the hell of it. The clock is a matched-color blue LCD display.
The blue LEDs are absolute distractions. Even during the day, with the lights on or the sun coming in the windows, my eyes want to focus on the blue lights instead of on the TV screen. I'm not sure whether it's the intensity of the LEDs, or the fact that the eyes are more sensitive to blue light. Probably some combination of both - they chose blue strobes on cop cars for a reason I guess - but whatever, it's damned annoying.
Give me a soft green LED any day. Enough with these bright blue ones.
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The problem is theft.
Over their long lifetime, even existing LED lights are much cheaper than incandescents (factoring in electricty and replacement costs). So they should be attractive to places like hotels, shops and so on.
One of the most serious problems is that the high intial cost makes the LED a very attractive target for thieves. Nobody's going to bother stealing incadescent light bulbs from, say, a hotel room - they're bulky, delicate and almost worthless. LEDs on the other hand, are compact, easily hidden, and quite valuable.
Current white LEDs will last up to 50,000 hours, about 50 times as long as a 60-watt bulb. That's almost six years if they're on constantly.
Erm. Weren't LEDs supposed to have (virtually) unlimited lifetime?
A big advantage of LEDs over standard lightbulbs is, that they are quickly switchable without reducing lifetime that much. For lightbulbs you need expensive flashlights, but for LEDs a standard 5mm High Power LED - or if you want more power, a flux - can be used for fast switching applications.
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Additionally you can use many LEDs together without much effort to create nice structures and designes in different colors - as mentioned in the article.
Since I discovered not so long ago, that the blue and white LEDs of today with e.g. 8000 and 20000mcd are another dimension compared to the LEDs I used in my electonic experimenting set as a child, I hacked together an XMMS-Plugin serial lightshow with a uC-backend and use some blue and red high-power LEDs to illuminate some parts of the room. With standard lights that fast-switching beat-detection would not be possible in such a cheap way.
Of course if you really want to illuminate the room in a standard, really bright manner, you need even more powerful and expensive LEDs, however it is a good start and I expect my main, ordinary illumination to be "lightshow compatible" in 10 years
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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.
The absolute best use for new-generation LEDs I have seen is for brake lights. Many high-end cars, and even some delivery trucks, use LEDs now, and the advantages are clear: they are damned bright, highly directional, don't burn out, and best of all, they reach full brightness a tenth of a second faster than an incandescent bulb. That may not sound like much, but at 60MPH, 0.1 second is 8.8 feet extra feet for the car behind you to start reacting (100km/h ==> 2.8m in 0.1s). I have blinky LEDs on my motorcycle and they solve all sorts of problems with tailgaters.
This is not my sandwich.
Excuse me, but iirc you are wrong about this.
LED's use the fact that at the P/N junction (that's what LED's actually are), electrons flow into a lower energy state, emitting the excessive energy as light. Since there hardly is any resistance in a ligt (typically less than 10^-14 Ohm), almost all electric energy is converted into ligt. You can also feel for yourself; led's won't get hot even after long operating times.
Gas ionisation tubes, however, are quite primitive. It's just accellerating some gas in an electric field, much of the energy dissipated by the field becoming kinetic energy of the gas ions, but there is also some energy needed to ionize the atoms.
When the ion strikes the fluorescent wall, most of it's kinetic energy indeed becomes ligt, but then again, some of it is lost just because the particle isn't massles. Not mentioned that starting up a tube costs significant amounts of energy.
Not sure if this is connected, but it could be related to the way that, after sitting outside in bright sunlight, then going inside, everything appears green.
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It did, actually. While you should have been able to carry a pistol and the flashlight at the same time, if you're switching weapons and there's only one flashlight there's no way in hell you're going to want to mount that on a single weapon.
But incandescents STILL don't match solar illumination.. which is why there are lights coming out that try to simulate it. I would guess that it would be possible to more closely approximate the solar spectrum with leds than incandescents eventually unless you can find a filament that can survive ~6300 K.
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