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LED Lighting As Cheap As CFLs Invented
mcgrew writes "New Scientist reports that a British team has overcome the obstacles to cheap LED lighting, and that LED lamps as cheap as CFLs will be on the market in five years. Quoting: 'Gallium nitride cannot be grown on silicon like other solid-state electronic components because it shrinks at twice the rate of silicon as it cools. Crystals of GaN must be grown at 1000C, so by the time a new LED made on silicon has cooled, it has already cracked, rendering the devices unusable. One solution is to grow the LEDs on sapphire, which shrinks and cools at much the same rate as GaN. But the expense is too great to be commercially competitive. Now Colin Humphreys's team at the University of Cambridge has discovered a simple solution to the shrinkage problem. They included layers of aluminium gallium nitride in their LED design... These LEDs can be grown on silicon as so many other electronics components are. ... A 15-centimetre silicon wafer costs just $15 and can accommodate 150,000 LEDs making the cost per unit tiny.'"
Now Colin Humphreys's team at the University of Cambridge has discovered a simple solution to the shrinkage problem.
Excellent news! Wait, what's this story about?
So I bought a 3 pack of LED lights that were supposed to be the equivalent of 40 watt bulbs...
A 25 watt incandescent bulb is about 10 times brighter. I was pissed. Might keep me from stumbling in the dark, but it doesn't really illuminate a damn thing.
I was so hopeful.
Stupid sexy Flanders.
Except I've already switched most of my house to bulbs that last longer than incandescents. Maybe the flourescents will start burning out by the time I can get some good cheap LED bulbs.
Honestly we NEED a led light bulb that will DIM acceptably for people.
most people want to be able to use dimmers and every customer I have wants to use lighting automation.
They need to work on that second right after figuring out how to get the lumens up to that of CFL lamps.
Do not look at laser with remaining good eye.
I have a Clapper that I've been unable to use with CFL bulbs. I'd like to know whether these new LED lights work with the Clapper and other remote-switching appliances.
These are going to be awesome in an office environment. Especially since the ceilings are so high and nobody likes changing the lights. But I have yet to find truly warm non-tungsten/halogen/mercury/fire/quartz/evil light for home use. I could not picture LEDs (which are basically antennas radiating a frequency that we happen to see) overtaking the other lights (heat sources that coincidentally give off visible light) in terms of color richness.
And it all came about because it's hard to achieve 1000C in a shed.
So what is the energy consumed during production for one of these LED lights?
If we're just using more energy per unit during manufacture, then what is the energy payoff balanced vs. the number of hours these will remain in service?
Aren't we already in short supply of gallium? Do we really want demand for this rare metal that already has so many uses? We have plenty of ways to generate light, let's use one that doesn't require one of our rarest and most useful materials.
Give me Classic Slashdot or give me death!
Lightbulbs getting out of a pool I guess.
I'm all for getting away from CFLs, as their production alone is NOT environmentally friendly (most of the mercury in the world is mined in China, where HALF of it is "lost" to the environment during production, which means "polluted"), not to mention the ratio thrown out.
But what about the LEDs? How toxic (or not) are the materials they're talking about? And what about the production of such? And heck, back on the pollution thing, WHERE they are produced makes a big difference, since if it's in China, forget any environmental disposal of chemicals used, whereas if it's in a developed country, it'll probably be OK.
Not insurmountable problems, but I do want to know how those things will work out.
I'm not sure everyone is completely aware of how big an advance this is. I'm going to buy Philips' stock as soon as I can. I'm sorry people have been screwed by some misleading marketing, but LEDs are the future of lighting... and the big green movement.
And yes, they're really easy to dim, either by converting to DC and modulating current, or by using a PWM - I'm not sure which is more efficient/cheaper.
I can't wait for CFLs to go away. Eventually you'll see commercially available, color-selectable LED bulbs.
Anyone know if the process was patented/sold to a specific company? Pretty obvious why...
The good ole' 5-year technology promise. Close enough to be exciting and get attention, but far enough away that you'll forget about their claim before they miss their deadline.
"Light Emitting Diodes are binary - either all the way on or all the way off"
You're smoking crack. LEDs can be dimmed just fine, by varying the current going through them. How do you think they control the brightness in LED-backlit LCD displays.
Aren't some solar panels made with GaN as well? Will this help them too?
That's just what women SAY to make LEDs feel better, but in the end, they always go home with some huge frosted incandescent with a harsh light. And the day after, they'll be crying to their LED friends about how much energy it wasted the night before, how it kept getting hot and leaving burns on her, and how it burned out after only a few thousand uses. And the LED will listen and be supportive, but you know she'll never give it a shot.
Not that I'm BITTER or anything...
This is great news not just for lighting, but also potentially for ILED TVs (basically LED - the "I" stands for inorganic. It would be simpler than even OLED, and the lifetime would be amazing of course.
Why OpalCalc is the best Windows calc
The real issue is that all light bulbs really do need to have the rating of lumens. Wattage is power use, lumens is light output (obviously). Saying "40-watt equivalent" is empty marketing speak, no wonder they were disappointing. And then there's the whole light temperature issue, which is very difficult for a consumer to determine.
For my LED experience, I went with these LED bulbs for my chandelier (I was looking for a "25-watt equivalent") and have been very pleased. It may help that it's a cluster of bulbs in my fixture. Considering the lifespan of LED bulbs, I'm willing to pay a lot more per bulb providing the light output falls in the appropriate range.
(1) LEDs can in fact be dimmed by running less current through them, however their power efficiency drops, which negates the whole purpose of LED lighting. The most efficient way to dim an LED is to strobe it on faster than the human eye can detect By varying with fraction of the on/off cycle that the LED is on, the human eye perceives this as "dimmer". The number of photons averaged over a second is reduced, but for the milliseconds the LED is on it is at full brightness.
(2) Incandescent bulb dimmers are almost never been rheostats, not since maybe the 1920s. The problem is efficiency again. Imagine a certain current flowing through the light bulb and the rheostat; the power dissipated in each device is then proportional to the resistance. When the rheostat is at equal resistance to the light bulb, it is dissipating as much power as the light bulb is! A 100 watt light bulb at 50% of the normal RMS current dissipates 25 watts, which means your rheostat is getting as hot as a small soldering iron. You'd need a massive heatsink to handle this.
Therefore for many years, dimmers were not very practical. The best dimmers were actually transformers, but they were extremely bulky. They were mainly used in theaters and fancy restaurants to soften the shock of the prices on the menu by relief at being able to find them at all.
With the creation of the solid state silicon controlled rectifier (scr), it is possible to do a trick with incandescent bulbs that is rather like the LED strobing trick. What you do is you take the sine wave power and you clip out the parts of the waveform on either side of the peak. So rather than having power delivered to light bulb all the time, the light bulb is only powered for a fraction of the cycle. The difference is that an incandescent filament glows because it is hot; it does not flicker on and off.
Now with respect LED light bulbs, I'm not sure about what circuitry they contain, but they do contain circuitry. If you just plugged enough LEDs in series to plug straight into AC, they'd flicker at a very noticeable 60Hz. If you put a full wave rectifier into the circuit, they'd flicker at 120Hz, which might be fast enough you wouldn't notice the flickering. You'd certainly be able to use the a solid state dimmer to dim such as circuit, but flickering might be noticeable.
There are relatively simple tricks you could use to maybe double the frequency, in which case you probably would not be able to perceive the flicker. On the other hand, there might be fancier circuits that know how to do the right thing. One of the problems with LEDs is that they age, their brightness varies. If the LED bulb achieves its white color by using several different colors, you need a compensating circuit to maintain the original color.
Of course you could use white LEDs, but most of the bright ones are very harsh; I've seen warm white LEDs advertised, but I've never had one.
So there you go, the straight facts on dimming that every geek should know.
Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
Plus, they tend to start off dim and take like 5 minutes to get to the brightness that they advertise.
You're buying the wrong bulbs then. Mine are at full brightness instantaneously.
When our name is on the back of your car, we're behind you all the way!
BZZZT, *WRONG*!!!
According to Energystar.gov:
Incandescent lights are on their way out in Australia. The only trouble with a complete ban, is that a lot of people hate CFLs, they can't be dimmed, they contain mercury, and they can't be used in extreme environments, like inside kitchen ovens.
Can LED lights be made to work inside (very hot) kitchen ovens? I know that some semiconductors can be engineered to work while white-hot, and wonder if it's so hard to design an LED light light that'll work inside an oven or kiln.
Commercial GaN on Silicon has been available for a years now. The commercial vendors have overcome this cracking problem due to thermal expansion using an AlGaN buffer since about 2005. One problem growing on Silicon is dislocations which limit lifetime, not cracking.
Actually sapphire substrates surprisingly are not that expensive.
I'm not sure why this press release is considered news.
Never has been, and probably never will be.
Indium and Gallium Sustainability â" September 2007 Update
The Kruger Dunning explains most post on
Granted this is an as yet unrealized technology, but I really wonder what the lumens per watt will be.
For reference a standard 48" T8 fluorescent is about 80 lumens per watt,
Compact fluorescent is around 65 lumens per watt,
and a 60w A19 bulb (the "normal" light bulb) is about 15 lumens per watt.
Cree has some Gallium nitride LEDs that (they claim) produce a record breaking 130 lumens per watt,
but they also have some 100 lumens per watt LEDs and they're also gallium nitride.
Cost of production isn't totally meaningless, but over it's 20 year life, 5 watts means more than $100.
There are a lot of places where the majority of power comes from nuclear and hydro.
Yes, and both of those power sources use a lot of energy to build. Then for nuclear there's pollution from mining as well as the waste.
Also, the real risk of CFLs is caused by the fact that any pollution from it is local and concentrated as a point source
Over a period of years I replaced almost all of my incandescent light bulbs with CFLs. As one burnt out I got a CFL to replace it. A point source of mercury is easier to handle than air born mercury. As for possibly breaking one, I try to use measures to reduce any possibility of breakage.
Also, consider that the plumes from garbage dumps invading your water supply
CFLs are supposed to be recycled and not thrown in the trash. Of course some people do throw them away, either because they don't care or because they don't know better. Even so, that's still less mercury in the environment than the amount of mercury that would be emitted to produce the power to light today's incandescent lights.
Which is why I hope these LEDs, or others, that are good for area lighting come onto the market within a couple of years.
trace mercury emitted into the atmosphere a hundred miles away from the city....
Not all power plants are 100 miles away from the city. There's more than one power plant in South Bronx. NYC has 25 plants serving it. The first ones built by Con Edison, used the used steam to heat neighborhood buildings.
Falcon
Should there be a Law?
I use CFLs, though I've had 3 out of the 8 I installed go bad within the first 2 years of use and still haven't found the time to "properly" dispose of them.
I too use CFLs. Like you I have 3 that burned out, however one lasted about 20 years. I don't know how long the others lasted. Also like you, I haven't disposed of them either. I put them in a room nobody uses in the packaging some of the CFLs I bought came in. When I find out where I'll take them in for recycling. I heard Home Depot was starting to accept them for recycling but I haven't seen my local store with a place to put them.
Falcon
Should there be a Law?
Nuclear power isn't clean.
Falcon
Should there be a Law?
A pointless tip for anyone:
Don't you hate it, in the middle of the night you have to have a piss. So you get up and can quite easily make you way to the toilet just by ambient light. You flick the light switch in the WC and do your thing. You finish and then switch the light off. Instantly you are thrown into total darkness. You stumble your way back to bed, hitting your shins and stepping on as many things as possible on your way. What can you do?
A simple solution is to close one eye before turning on the light. Keep this eye closed tight as long as the light is on. After you switch the light off, open your eye. You can still see quite well in the ambient light again with the eye you had closed as it did not adjust to the brightness of the light.
it is only after a long journey that you know the strength of the horse.