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LED Lighting As Cheap As CFLs Invented

Soulskill posted more than 4 years ago | from the bright-ideas dept.

Technology 553

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.'"

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553 comments

Finally! (5, Funny)

1729 (581437) | more than 4 years ago | (#26654727)

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?

Re:Finally! (-1, Troll)

jollyreaper (513215) | more than 4 years ago | (#26654857)

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?

Prostate stimulation.

Oblig seinfeld reference (5, Funny)

philspear (1142299) | more than 4 years ago | (#26654949)

Lightbulbs getting out of a pool I guess.

Re:Finally! (0)

Anonymous Coward | more than 4 years ago | (#26655185)

Shrinky Dinks [wikipedia.org] FTW

My first experience with LED lighting... (4, Insightful)

gfxguy (98788) | more than 4 years ago | (#26654743)

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.

Re:My first experience with LED lighting... (4, Insightful)

gnick (1211984) | more than 4 years ago | (#26654813)

I've heard similar reviews from a co-worker who was very motivated to 'go green'. The '40-watt equivalent' turned out to be an over-sized night-light (per her review - I haven't seen it).

Still, this could be good news. I switched about half-way to CFLs largely to save $$ on electricity, but they're neither as efficient nor as 'green' as LED lights. I priced LED lights but, at the time, they were so damned expensive that it would take ~40 years for the investment to pay itself off. Even if I have to over-rate everything to get the same level of light, it should be better all the way around compared to the current alternatives.

Still, even though this sounds solid, the ominous 'This should be available in 5 years' always makes me a little cautious.

What about the production? (5, Interesting)

Erioll (229536) | more than 4 years ago | (#26654953)

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.

Re:What about the production? (4, Insightful)

Idiomatick (976696) | more than 4 years ago | (#26655017)

If you only replace them at 1/10th or 1/1000th the rate then its unlikely it could be bad for the environment....

Re:What about the production? (1)

Bearhouse (1034238) | more than 4 years ago | (#26655099)

If they are produced in a typical fab then the technology is known & proven and the environmental issues too...most fabs are outside China and subject to pretty draconian environmental controls.

Also, these things are pretty small, so consume less raw materials and require less transport...

All in all, a win all around, although - as someone has mentioned here - LEDs are not that 'bright' compared to traditional lighting.

Re:What about the production? (5, Funny)

lagfest (959022) | more than 4 years ago | (#26655273)

All in all, a win all around, although - as someone has mentioned here - LEDs are not that 'bright' compared to traditional lighting.

I take it you've never seen a high power LED. All I can say is: don't look into high power LEDs with remaining eye.

Re:What about the production? (0)

Anonymous Coward | more than 4 years ago | (#26655117)

not sure about the details but some sources say that the new Aluminium gallium nitride could be mildly toxic. this set, raw exposure rather then in-blub is toxic for other bulbs too.

Re:What about the production? (1)

CompMD (522020) | more than 4 years ago | (#26655331)

Gallium is very toxic. Its not something you just want to throw out with your daily trash.

Re:What about the production? (5, Informative)

danep (936124) | more than 4 years ago | (#26655385)

Please stop spreading the FUD about the amount of mercury in CFLs, which is negligible. The mercury in CFLs constitutes 0.1% of what we dump into the environment annually, and CFLs contribute far less mercury to the environment than incandescent bulbs. http://www.energystar.gov/ia/partners/promotions/change_light/downloads/Fact_Sheet_Mercury.pdf [energystar.gov]

Re:What about the production? (0)

Anonymous Coward | more than 4 years ago | (#26655519)

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

This is a very poor choice of words. China is hugely developed. It's not some backwater peasant village. China has over fifty cities with a population of 1 million or more, and Shanghai is the fourth most populated city in the world and absolutely dwarfs most American cities in size.

Re:My first experience with LED lighting... (-1, Flamebait)

zwei2stein (782480) | more than 4 years ago | (#26655061)

They are not even green either.

Combined pollution from making em + using em + disposing them is order of magnitude worse than conventional lightbulbs.

Re:My first experience with LED lighting... (2, Insightful)

DFJA (680282) | more than 4 years ago | (#26655263)

.....and your data source for this claim is where exactly???

Re:My first experience with LED lighting... (2, Informative)

pla (258480) | more than 4 years ago | (#26655277)

Combined pollution from making em + using em + disposing them is order of magnitude worse than conventional lightbulbs.

...If you just throw them in a landfill.

If you properly "dispose" of them (aka "recycle"), you can reuse just about every part of them except the small PCB in the base, and even that you can strip for the metals.

So yeah, they have a tiny blob of mercury in them - Of which, when properly recycled, 99.999% should end up in a new bulb.

Re:My first experience with LED lighting... (0)

Anonymous Coward | more than 4 years ago | (#26655539)

Hey. You seem like you care, but your argument is flawed. People won't bother with recycling, at least not the nay sayers and anti-change people. You have to concedr people WILL just throw them out.

Instead point out that most power comes from coal (50%+ in the US) and that coal power releases mercury right into the air. Since the CFL uses less energy, 1/10 to 1/7 for actual lumen equivalence, the mercury released from broken lights is still about a fifth of that of an incandescent.

Re:My first experience with LED lighting... (0)

Anonymous Coward | more than 4 years ago | (#26655193)

"Still, even though this sounds solid, the ominous 'This should be available in 5 years' always makes me a little cautious."

In the Metro this morning the article read more along the lines of "hopefully 2 years, 5 years at most". This is hopeful.

So now they can make bright LEDs for lighting purposes for pennies apiece. Brilliant. Then you add on the AC/DC convertor thingy, and attach 50 of these LEDs to it to achieve a decent light. Oh, can you have a range of wavelengths please to simulate natural light rather than a single, harsh, light?

We need lumens ratings (4, Insightful)

kherr (602366) | more than 4 years ago | (#26655465)

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 [theledlight.com] 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.

Re:My first experience with LED lighting... (4, Informative)

rolfwind (528248) | more than 4 years ago | (#26655505)

I switched about half-way to CFLs largely to save $$ on electricity, but they're neither as efficient nor as 'green' as LED lights.

How so? Recently, in my local walmart, GE started selling Par20 LED bulbs that were supposed to be 40-50 watt equivalent but for 7 watts produced 200 lumens. That's 28.5 lumens per watt.

My Feit Electric (Costco) 13w CFLs (60 watt equivalent) produce about 800 lumens. That's 61 lumens per watt.

A 60w incandescent makes around 700-850, depending on brand. Using the 800 as a comparison, thats 13.3 watts per lumen.

LEDs may have the potential to be more efficient than CFLs, but it doesnt look like they automatically are. Or am I missing something?

Re:My first experience with LED lighting... (0)

Anonymous Coward | more than 4 years ago | (#26654823)

Learn to see in IR

Re:My first experience with LED lighting... (4, Informative)

mcgrew (92797) | more than 4 years ago | (#26654915)

Don't lose hope yet. For one thing, a 40 watt incandescant (you didn't specify if what you were replacing was incandescant or CFL) is damned dim to start with. When I used incandescants, the lowest watt bulb I used was usually a 100 watt (60s in closets and in the basement where there's one every fifteen feet), and used 3 way 250 watt bulbs for reading.

A 40 watt CFL would be damned bright, I don't know if I've ever seen one. Most of my lamps have 27 watt twirley tubes. They vary in intensity, in color, in startup time, and some grow brighter the longer they're on. The one on the front porch won't light if the temperature gets below 0F, the back porch light has lit every time. It's also dimmer and bluer.

I'm looking forward to these, but when I finally buy one, I'm not going to pick one that says "equivalent to a sixty watt incandescant", I'm going to get one that says it's equivalent to 100 watts, just to be sure.

Re:My first experience with LED lighting... (1)

cream wobbly (1102689) | more than 4 years ago | (#26655195)

A 25W incandescent is easily bright enough to illuminate a fair-sized room. Of course, I'm talking about a white painted room not lined with heavy tapestries; a room lacking family portraits by the masters, suits of armour, and my grandfathers' hunting trophies; and sans a dark-stained wooden floor thick with the dander of aeons.

You could save a hell of a lot of money by ditching the clutter and painting the room in a bright, happy colour.

Re:My first experience with LED lighting... (1)

beelsebob (529313) | more than 4 years ago | (#26655317)

Uhhh, you've been smoking something funny if you think a 25W incandesant bulb can light a room. 40W is commonly used for crappy little reading lamps!

Re:My first experience with LED lighting... (1)

Kokuyo (549451) | more than 4 years ago | (#26655353)

And who exactly wants to live in something that resembles a hospital?

Re:My first experience with LED lighting... (1)

shaitand (626655) | more than 4 years ago | (#26655363)

'A 25W incandescent is easily bright enough to illuminate a fair-sized room.'

If you consider 'bright enough' to be just enough illumination to keep you from stumbling over things. A 60 watt incandescent will still leave shadows in a completely empty living room painted white. I know, I've stuck them in lamps while moving in.

Re:My first experience with LED lighting... (0)

Anonymous Coward | more than 4 years ago | (#26655439)

You could save a hell of a lot of money by ditching the clutter and painting the room in a bright, happy colour.

Think about how many electrons you and your countrymen could save by getting with the program and dropping 'u' from "color".

(Sorry, I couldn't resist)

Re:My first experience with LED lighting... (0)

Anonymous Coward | more than 4 years ago | (#26655219)

What the hell are you talking about? A 40W incandescent is an excellent light source - brighter than a pretty big fire or the largest candle known to man. IMO, a typical domestic living room is nicely illuminated by 3-4 35W tungsten halogen lamps. 100W lamps might be fun for heating the room or some kind of ill-advised attempt to simulate daylight, but why piss your body off? As for using a 250W bulb for reading, I can only imagine the S/N ratio of your eyes is substantially below average. You do realise that about 225W of that rating is just radiated heat, don't you?

Re:My first experience with LED lighting... (2, Informative)

shaitand (626655) | more than 4 years ago | (#26655555)

'A 40W incandescent is an excellent light source - brighter than a pretty big fire or the largest candle known to man.'

In home lighting isn't rated against candles or big fires (unless you are looking for mood lighting) its compared to daylight.

'a typical domestic living room is nicely illuminated by 3-4 35W tungsten halogen lamps'

Yeah, I'm sure 110w of HALOGEN would be reasonably bright. But we were referring to indoor lighting. The gas in the bulb would be argon.

Re:My first experience with LED lighting... (1)

MobyDisk (75490) | more than 4 years ago | (#26654993)

Don't trust their "equivalent to..." things. Look at the lumens [wikipedia.org] which is listed for both the incandescent bulb, and the LED bulb.

This rule goes for buying CFLs too: They often over-estimate by about one level. (Ex: A "40-watt equivalent" is really a 25-watt. A "60-watt equivalent" is really a 40 watt. Etc.)

Re:My first experience with LED lighting... (1)

DFJA (680282) | more than 4 years ago | (#26655045)

Having had a similar experience I'm very tempted to report the suppliers of these products to Trading Standards (UK) as it is a clear case of mis-representing the product being sold. It's perfectly possibly to make an accurate comparison by using lumens, I can think of only one reason why suppliers don't do this - because they wish to misrepresent the product. Having said that, some suppliers do quote lumens in some cases, but it needs to be consistent.

Re:My first experience with LED lighting... (1)

zappepcs (820751) | more than 4 years ago | (#26655217)

I'm hoping that someday soon we'll be able to buy wall coverings that are LED lighting. I don't care if the light comes from the ceiling or not, give me a whole wall or three of variable light output LEDs. You can even make it the ceiling if you want, I don't care...

I think we'll be able to do many exciting things with new lighting technologies, and I for one welcome our new overhead lighting LEDs

Sweet (4, Insightful)

internerdj (1319281) | more than 4 years ago | (#26654769)

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.

Re:Sweet (1)

mcgrew (92797) | more than 4 years ago | (#26655173)

Same here; the only two incandescants left are in sockets in the bathroom, and they're the candelabra type (it's a 1930s era house) by the irrir and a twirley bulb won't fit.

Those will be gone soon too, as I've recently seen some CFLs that will fit. I've been using CFLs for a decade now, I haven't had too many burn out yet.

Re:Sweet (1)

internerdj (1319281) | more than 4 years ago | (#26655241)

We've been slowly replacing over the past 4 years. One of my first purchases was a 3-way but it has really been the only one that I've lost from burning out. I've lost a couple to knocking-over the lamp.

If they are still not dimmable they still suck (4, Insightful)

Lumpy (12016) | more than 4 years ago | (#26654771)

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.

Re:If they are still not dimmable they still suck (1)

gfxguy (98788) | more than 4 years ago | (#26654833)

I wonder if discrete stepping for dimming an LED bulb would work... you know, 5 steps: off, 1/4 of the LEDs, 1/2, 3/4, and all?

I would imagine that you could work the logic into the bulb depending on how much juice it's getting, but then I have a pretty good imagination.

Re:If they are still not dimmable they still suck (1)

jjmcwill (3739) | more than 4 years ago | (#26655019)

See this article on how dimmers work.

http://www.icanhome.com/downloads/iLIGHT%20Binder-HowDimmers.pdf [icanhome.com]

You'd need a circuit that detects the average power supplied, as opposed to looking at the voltage level of the rectified peak output. I haven't done EE in like 12 years, so maybe this is simple to do. *shrug*

It sounds like a cool project.

Re:If they are still not dimmable they still suck (2, Informative)

Sj0 (472011) | more than 4 years ago | (#26655077)

Actually, you should be able to use a standard dimmer switch on these things. Unless someone is doing something I've never seen before, there's no logic in them, just the diode and a resistor. Maybe a capacitor if they were really ambitious.

I'd expect control with an LED to be much better than an incandescent, because the fact that the 'light emitting' voltage stays relatively constant between the on state and off state, so you should get better effective rangability and control.

Yes, I'm a control systems geek. :P

Re:If they are still not dimmable they still suck (4, Informative)

gnick (1211984) | more than 4 years ago | (#26654871)

I've not used the commercial LED light bulbs, but standard LEDs dim just fine (at least to a point). I see no obstacle that would stop the bulbs from dimming too.

In fact, a very quick check on the bulbs available at Amazon indicates that they do dim. Is there a dimming problem that you're aware of that's not made clear in the Amazon reviews?

Re:If they are still not dimmable they still suck (-1)

mcgrew (92797) | more than 4 years ago | (#26655063)

standard LEDs dim just fine

Not really; not like an incandescant. An incandescant dimmer is simply a rheostat (variable resistor), but Light Emitting Diodes are binary - either all the way on or all the way off. To dim an LED what you do is turn it off and on faster than the eye can see. The longer the off period, the dimmer it appears.

Dimmers for LED lamps will most likely come on the market, but the dimmer that's on you wall now won't work.

you sir are incorrect (3, Insightful)

Chirs (87576) | more than 4 years ago | (#26655125)

"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.

Re:you sir are incorrect (4, Insightful)

nwf (25607) | more than 4 years ago | (#26655281)

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.

While you can dim them that way, they are very picky and inefficient. PWM is much, much more efficient and allows for nearly 1-100% dimming range easily. Getting such accuracy with current is very hard, since it's nonlinear. Most LCD backlighting is done via PWM, there are tons of tiny chips to do this efficiently, for phones too. It's just too easy and cheap not to use PWM these days.

Fail (0)

Anonymous Coward | more than 4 years ago | (#26655179)

Incandescant dimmers are not simply variable resistors. Look up Ohm's Law for why this won't work.

Dimmers work using Triacs or SCRs to slice the AC waveform in time. This will work fine for LEDs too.

Re:If they are still not dimmable they still suck (4, Informative)

Sj0 (472011) | more than 4 years ago | (#26655225)

It's hard to take you seriously when you don't know about a SINGLE component in the system.

First, LEDs are definitely variable in a non-binary sense. Anyone who has ever used an LED in pretty much any application ever can tell you that light output can be changed by altering the current.

Second, a dimmer isn't a variable resistor. It cuts the AC waveform, reducing the current available to an incandescent light bulb.

Pulse width modulation is definitely NOT the only way to vary the light output of an LED.

Re:If they are still not dimmable they still suck (1)

scharkalvin (72228) | more than 4 years ago | (#26655301)

LED's can be dimmed one of two ways, by varying the current or by varying the duty cycle. The duty cycle method does work better however. Conventional incandescant lamp dimmers use Triacs or SCRs to vary the duty cycle, so they will work just fine. The ballasts of CFL's don't take kindly to short duty cycles (they tend to explode) so unless the CFL has a special ballast adapted to this use they can't be dimmed.

Re:If they are still not dimmable they still suck (1)

ninjackn (1424235) | more than 4 years ago | (#26655337)

LEDs are not "binary". To dim an LED all you need to do is limit the current, which can be achieved one of many ways.

If you did decide to limit the current by turning it on and off really fast then you would probably want to change the duty cycle, not the period.

The "problem" with dimming LEDs comes from the fact that the power we get to our houses are AC. The AC has to be converted to DC for the LEDs and the regulators and probably are doing too good of a job compensating for when the AC voltage drops ala the standard light bulb wall dimmer knob.

Re:If they are still not dimmable they still suck (1)

hairykrishna (740240) | more than 4 years ago | (#26655383)

None of that's true. Firstly, you CAN dim an LED by reducing the current through it. Secondly, incandescent dimmer switches are not variable resistors they are triacs.

Ok, let's get this thread straightened out. (5, Informative)

hey! (33014) | more than 4 years ago | (#26655585)

(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.

Re:If they are still not dimmable they still suck (1)

Lumpy (12016) | more than 4 years ago | (#26655327)

Yes. el-cheapo dimmers work on SOME of them. But high end dimmers all need a minumum load and most LED lighting designs do not meet this. the units that are a decent output (3 3W luxeon led's) are NOT dimmable as the electronics inside dont like it.

The garbage LED lighting that is simply a wad of cheapie T1 led's and a bridge rectifier are not what are the most useful as they do not have high enough light output ot be a good replacement.

Re:If they are still not dimmable they still suck (1, Informative)

Anonymous Coward | more than 4 years ago | (#26654899)

You can trivially dim LEDs using PWM, which is more or less the same method used by regular dimmer switches. An LED light which was as simple as a chain of LEDs designed to run off rectified 110VAC/240VAC should work fine with a regular dimmer.

Re:If they are still not dimmable they still suck (1)

pla (258480) | more than 4 years ago | (#26655167)

You can trivially dim LEDs using PWM

Yes and no...

If you boost the frequency to a few thousand Hz, yes, you could arbitrarily dim them via PWM. At 60Hz (half-wave rectified, ugh) or even 120Hz (full-wave, better but still noticeably particularly with a duty cycle less than 50%), you just can't do that without making half the people in the room nauseous.

As currently implemented, even the dimmable LEDs really, really suck. Of course, I personally couldn't care less about true dimmability, as long as I can get at least a few different levels by simply turning off N out of every M LEDs.

Re:If they are still not dimmable they still suck (2, Interesting)

tlhIngan (30335) | more than 4 years ago | (#26654951)

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.

As long as your dimmers are the electronic PWM based kind, LEDs will work with them. (CFL's have issues when they're only given part of the sinewave). If you use the crappy rheostat dimmers LEDs won't work with them.

The only thing I question about LEDs is... will they give us headaches from the flicker? It's my current annoyance with LED christmas lights - they can flicker quite horribly. CFLs not so much, and neither the standard flourescent lamps (flicker at 120Hz, plus smoothed out by phosphors).

I forsee cheap LED lamps not using a full bridge rectifier (= 120Hz flickering), and just hooking them straight up in series, so they're off half the time.

It's also one of my concerns with OLED displays - they have these really fast refresh times, but if you don't refresh them fast enough, flicker! (I've seen it on cheap MP3 players, annoying. I've also seen it on the Sony OLED TV... Sony sales guy blamed it on the 1080p24 source, but I'm not sure.)

Re:If they are still not dimmable they still suck (1)

CannonballHead (842625) | more than 4 years ago | (#26655329)

Headaches... it's an excellent question. There were LED lights decorating a place that I went to last year, and one particular strand of them made me sick/dizzy/lightheaded. All the others were fine, but these were definitely not.

Fluorescent lights can do the same thing, though. It's a "weird" light and does make quite a few people that I know feel somewhat sickish.

Re:If they are still not dimmable they still suck (1)

Ambiguous Coward (205751) | more than 4 years ago | (#26655335)

The only thing I question about LEDs is... will they give us headaches from the flicker? It's my current annoyance with LED christmas lights - they can flicker quite horribly.

I think this is due to the 60hz you're getting off the AC. It's easy enough to overcome: simple AC-DC converter, like the wall-wart for your laptop (but no need for one capable of 70 watts or whatever your laptop draws, so it can be itty-bitty), but as always, it adds cost.

Re:If they are still not dimmable they still suck (1)

Idiomatick (976696) | more than 4 years ago | (#26655067)

Uhh led lights are dimmable... without flickering and all that... But they are just not bright enough atm to be worth anything.

Re:If they are still not dimmable they still suck (1)

cmr-denver (1315039) | more than 4 years ago | (#26655261)

I'm sure this is a stupid question, but since most of these LED "bulbs" are just an amalgamation of several individual LEDs, wouldn't just turning off some percentage of them be better than trying to do PWM?

Re:If they are still not dimmable they still suck (1)

Rogerborg (306625) | more than 4 years ago | (#26655347)

most people[who? [wikipedia.org] ] want to be able to use dimmers [Citation needed [wikipedia.org] ]

Fixed that for you.

Re:If they are still not dimmable they still suck (1)

shaka999 (335100) | more than 4 years ago | (#26655395)

Normal incandescent bulbs work by lowering the voltage over the bulb. If I understand correctly this isn't a good approach for LED based lighting. You really want to do pulse width modulation (PWM) where you switch the device on/off at different rates to dim the light. A simple circuit in the bulb could do this based on changing voltage but it would add some cost.

Oh, and I'm sure we will have people saying they can see the blinking even if its in the Khz range...

Demand for dimmer switches (1)

sjbe (173966) | more than 4 years ago | (#26655421)

Honestly we NEED a led light bulb that will DIM acceptably for people.

OK, I'm down with this. A low energy consumption dimmable bulb would be a useful thing indeed.

...most people want to be able to use dimmers

"Most"? Really? I think your argument ran off the rails here. There is nothing preventing people from using dimmer switches now - they just can't use most CFLs in those sockets. I think "most" people don't really care and the evidence for that is that CFL bulbs, which generally aren't dimmable, are selling like hotcakes [earth911.com] and increasing rapidly. Many houses might have some dimmers but usually not everywhere. That's not to say dimmable switches aren't a good idea but let's not overestimate the demand for them shall we?

Clap on? (4, Funny)

Pentomino (129125) | more than 4 years ago | (#26654773)

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.

Re:Clap on? (5, Informative)

ivan256 (17499) | more than 4 years ago | (#26654887)

They won't work with the clapper.

Cheap automated switching devices like the clapper and some timers include the bulb as a resistance element in the switching circuit. They count on the bulb acting almost like a short when the light is off. This works with incandescent bulbs, since the resistance of the filament is very low when it is cold. CFL and LED bulbs act exactly the opposite way. They are almost an open circuit when off. With no current flow, the automated switch is unpowered.

There are switches that will work with these types of bulbs, but they generally cost more.

Re:Clap on? (1)

EvanED (569694) | more than 4 years ago | (#26655245)

Wow, I just figured the parent was on crack. I couldn't imagine a reason that the type of bulb would affect that, but that was quite interesting.

Whoopie for cold light! (4, Interesting)

arugulatarsus (1167251) | more than 4 years ago | (#26654775)

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.

Cheap? Yes. Practical? Well... (0)

Anonymous Coward | more than 4 years ago | (#26654845)

Even if they make LED lighting as cheap as CFLs, the light given off is still brutal compared to other forms of lighting(basically 255R+255G+255B=white), and they're still not as efficient as CFLs.

The biggest perk is insane reliability and shock resistance. We won't be seeing LED lighting in our homes any time soon, but I could see white LED lighting replacing incandescent bulbs in cars, trailers, and other applications where you don't want to deal with a burned out light bulb.

Re:Cheap? Yes. Practical? Well... (0, Offtopic)

Sj0 (472011) | more than 4 years ago | (#26655373)

Ouch, I get on the first page then click "Post Anonymously"...

Re:Cheap? Yes. Practical? Well... (1)

slim (1652) | more than 4 years ago | (#26655413)

I bought a set of LED GU10s for my kitchen.

I had no problem with the colour or the brightness of the light. The problem was that the spread was way too low, so there were pools of adequate brightness directly below the lights, while the rest of the room would be uncomfortably dim.

Of course, if they used a lens or something to spread out the light, maybe nowhere would be acceptably bright.

Still, I'm optimistic for improvements. These were *nearly* good enough, which is more than I can say for CFLs.

The same place sold colour-cycling LED GU10s. Those were dim, but cool :)

British invention (4, Funny)

EdZ (755139) | more than 4 years ago | (#26654863)

And it all came about because it's hard to achieve 1000C in a shed.

Are they going to be tiny? (1)

javilon (99157) | more than 4 years ago | (#26654885)

A 15 cm silicon wafer: 15x15=225cm2
If they fit 150000 LEDs you get 225/150000=0.0015 cm2 per led.

Aren't they too small to be used for home lights?

Re:Are they going to be tiny? (1)

larry bagina (561269) | more than 4 years ago | (#26654963)

that's not the size of the LED, it's the size of the gallium components.

Re:Are they going to be tiny? (4, Funny)

Anonymous Coward | more than 4 years ago | (#26655285)

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...

Re:Are they going to be tiny? (1)

ericrost (1049312) | more than 4 years ago | (#26655031)

Wafers are a disk, so pi * 7.5^2 = 176.7144375 cm^2 so you get area/150000 = 0.00117809625 cm^2/led.

Also, 1 LED != 1 LED "lightbulb" is also != 1 LED with package size.

Re:Are they going to be tiny? (1)

JustinOpinion (1246824) | more than 4 years ago | (#26655069)

Wafers are usually circular (since they are sliced off a cylindrical ingot), so the calculation would actually be [google.com] :

( pi*(15cm/2)^2 )/150000 = 0.0012 = 0.12 mm^2

Which is slightly smaller. But this means that each LED is roughly [google.com] 0.3 mm in size, which is about the size of any LED I've ever encountered.

I presume a real lightbulb would require multiple LEDs bundled together somehow. Which is actually cool, because it would allow for more interesting bulb shapes, and should allow for dimming (by controlling how many LEDs are lit). Of course it also means that the real cost of a bulb is higher than a single LED. But even if a bulb needs 100 LEDs, if the price quoted in the summary is correct,* bulbs will be very cheap [google.com] .

(* The price quoted in the summary is probably not correct. The cost of the wafer doesn't include the manufacturing costs or the costs of the materials you need to deposit onto it.)

Re:Are they going to be tiny? (1)

MoonBuggy (611105) | more than 4 years ago | (#26655081)

The actual diode is always tiny, the main visible part of what one would call an LED is just a plastic lens. If you look at the full-resolution version of this [wikipedia.org] close up on Wikipedia you can get a fairly good view of the tiny wire filaments connected to the actual LED inside the reflector.

Of course, even the completed component is still only ~5mm in diameter so a bulb would still use an array of them, just like they do now.

Cheap by what measure? (2, Interesting)

ChilyWily (162187) | more than 4 years ago | (#26654905)

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?

Re:Cheap by what measure? (1)

slim (1652) | more than 4 years ago | (#26655479)

My impression is that they'll last pretty much indefinitely. I have 12 halogens in my ceiling, and seem to replace one every couple of weeks. Upgrading from 26 per year to none, would be a big plus.

Gallium (2, Interesting)

Hatta (162192) | more than 4 years ago | (#26654947)

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.

Re:Gallium (1)

MightyYar (622222) | more than 4 years ago | (#26655199)

Aren't we already in short supply of gallium?

This is a very thin layer of gallium applied to a substrate. Contrast this to the use of gallium in cell phones, where IIRC it is being used as the substrate. I don't think LED production will come anywhere close to denting the gallium supply compared to cell phones.

Re:Gallium (-1)

Anonymous Coward | more than 4 years ago | (#26655215)

dont know for sure but however much gallium we have do we have more of the elements the other light types are made of.

Re:Gallium (0)

Anonymous Coward | more than 4 years ago | (#26655369)

I agree. We need to conserve our gallium supply. We especially need to make sure the most useful products like energy efficient lighting are not sacrificed by this new technology.

Re:Gallium (1)

meza (414214) | more than 4 years ago | (#26655535)

Wikipedia doesn't imply that Gallium is rare and lists Semiconductors and specifically LEDs as one of the main application.

Even if you are right I don't think we are talking about much Gallium here. The article doesn't say anything about layer thickness but I would assume it is in the order of 1um. Assuming a square wafer 15cm * 15cm * 1um = 0.0225 cm3. Density of Galium is around 6g/cm3 so on the wafer we need 0.135g of Galium (ignoring that the layer also includes aluminum and nitride).

I have no idea of the efficiency of material use when depositing the layer but even if you need 10 gram of Ga it doesn't sound like that much to me for 150 000 light bulbs. World production in 2007 of Ga was 184 tonnes (wikipedia) so giving up some of that should give us plenty of light bulbs for everyone. And it would seem like a pretty useful cause to me since changing to LED would reduce energy use and CO2-emissions from households quite a lot.

LEDs are not efficient (0)

Anonymous Coward | more than 4 years ago | (#26655013)

Most LEDs are not as efficient as CFL anyway. Not at a good output level.

Big advancement (5, Interesting)

rift321 (1358397) | more than 4 years ago | (#26655023)

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...

Re:Big advancement (0, Flamebait)

Sj0 (472011) | more than 4 years ago | (#26655449)

If anyone rectifies the voltage heading TO an LED light bulb, they should have their engineering degree taken away.

Protip: LEDs are diodes. Rectifiers are diodes. Just stick a current regulating resistor in series, stick a voltage smoothing capacitor in parallel, and use a regular dimmer to limit the current to whatever you need. Using a complicated solution to the problem would be criminal.

Ahh, 5 years... (5, Insightful)

PowerVegetable (725053) | more than 4 years ago | (#26655055)

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.

Re:Ahh, 5 years... (1)

avandesande (143899) | more than 4 years ago | (#26655107)

Traditionally semiconductor advances are quick to come to market. I don't see anything in the article that suggests this is anything more complicated than the tweeks that CPU manufacturers routinely make to their processes.

Re:Ahh, 5 years... (3, Funny)

Junior J. Junior III (192702) | more than 4 years ago | (#26655235)

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.

I just updated the "desktop" image on my OLED t-shirt to read "PowerVegetable is right on!"

Solar panels too? (2, Interesting)

MobyDisk (75490) | more than 4 years ago | (#26655127)

Aren't some solar panels made with GaN as well? Will this help them too?

Re:Solar panels too? (4, Informative)

giafly (926567) | more than 4 years ago | (#26655251)

Aren't some solar panels made with GaN as well? Will this help them too?

Looks likely. Cambridge are researching that too, e.g. both fields are covered by the following grant application.

The other approach to solar cells we will pursue is high-efficiency inorganic multilayer solar cells. The basic idea is that by stacking layers in the order of their bandgap, with the layer with the largest bandgap at the top, light is converted into electricity in the most efficient way. We propose to build an innovative multi-layer solar cell based on GaN/InGaN/Si. The GaN layer will absorb the UV part of the solar spectrum, the InGaN layer the blue and green parts and the Si layer the yellow, red and near-IR parts. The theoretical efficiency is above 60%. Such a cell would be too expensive for large-area applications, but would be designed to be used at the focus of mirrors that concentrate the solar light, which will make the technology competitive.

GaN-based white lighting is extremely efficient and if used in our homes and offices it could save 15% of the electricity generated at power stations, 15% of the fuel used, and reduce carbon emissions by 15%. However for GaN-based white lighting to become widely used in homes and offices we have to increase the efficiency still further and reduce the cost. We will research various ways to increase the efficiency. To reduce the cost we will grow GaN-based LED structures on 150mm (six-inch) silicon wafers instead of the current growth on two-inch sapphire wafers. This would reduce the LED cost by a factor of ten. Cambridge will grow such LED structures and UCSB will process them into LED lamps.

Details of Grant [epsrc.ac.uk]

Good news but... (0)

Nautical Insanity (1190003) | more than 4 years ago | (#26655159)

the march to phase out incandescent lights in favor of CFLs has already begun. I personally am concerned about the five years until this product will be released. As of yet we have no plan for disposing of CFL bulbs and even if we did that wouldn't stop many foolish people from simply throwing them in the trash anyway.

The cost of the mercury polluted into the environment from CFLs far outweighs any energy savings they may incur over incandescent lights.

Quick LED question. (1)

hack slash (1064002) | more than 4 years ago | (#26655187)

I made my own front light for my bike by embedding 60 3mm LEDs into a standard Cateye reflector, it works well & is nicely bright but I always have this want for more brightness, but not at the expense of increasing the physical size of the light by using Cree's or Luxeons whigh require a collinator to direct the light.

So does anyone have any ideas how I can easily file down a couple of hundred 3mm LEDs so they're identically rectangle or square to pack them tightly together?

Re:Quick LED question. (1)

scharkalvin (72228) | more than 4 years ago | (#26655387)

Instead of using standard 3mm LED's use SMT types. They are already the size you need and are available in the same brightness as the 3mm kind. You will need to use a circuit board and special soldering tools though....

Re:Quick LED question. (1)

hack slash (1064002) | more than 4 years ago | (#26655531)

I regularly solder SMD components including LEDs but the reason I like the 3mm LEDs is the beamspread they give, most cheap 5mm LEDs produce a spotlight effect where if an object isn't in the ~15-25 degree beam it can't be seen that well, whereas cheap 3mm LEDs have a nice smooth drop-off gradient which is ideal for night cycling as the path/unlit road in the distance is illuminated just as much as it is near you.

Re:Quick LED question. (1)

giafly (926567) | more than 4 years ago | (#26655473)

LEDs lose efficiency if they hot, so it sounds like you'd need a big heat sink for your close-packed array of 200 lights. Google for: LED "heat sink". Perhaps you could use several smaller arrays, bolted to the metal of your bike. Warm handlebars might be welcome in Winter.

Re:Quick LED question. (1)

hack slash (1064002) | more than 4 years ago | (#26655593)

The 60 LED array I put together does get a little warm but it hasn't been much of a problem because they're only turned on at night when it's naturally cooler than the day and only on for long periods when I'm moving along so the air flowing over it will help keep it cool.

Re:Quick LED question. (0)

Anonymous Coward | more than 4 years ago | (#26655529)

Buy smaller LEDs.

Good for displays too (3, Interesting)

Twinbee (767046) | more than 4 years ago | (#26655325)

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.

My opinion (1)

tripdizzle (1386273) | more than 4 years ago | (#26655379)

I hate those pigtail lights. Makes me feel like I'm still at work or school when at home using that disgusting white lighting.
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