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.'"

Comments

Finally!

[1729]

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?

My first experience with LED lighting...

[gfxguy]

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...

[gnick]

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.

Re:My first experience with LED lighting...

[mcgrew]

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...

[rolfwind]

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...

[rolfwind]

+ disposing them is order of magnitude worse than conventional lightbulbs.

Any home depot accepts any and all CFLs. In fact, it's easier and cheaper to dispose of CFLs properly than it is of Fluorescents.

Oh, and if your electricity is generated from coal, you are helping put mercury in the air as well.

Re:My first experience with LED lighting...

[stonefry]

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

Your friendly neighbourhood CDO neat-freak???

Fixed it for you. The letters are now in alphabetical order. LIKE THEY SHOULD BE!

Re:My first experience with LED lighting...

[camperdave]

I don't trust lumens either. The lumen output of CFL lighting halves every foot or so from the light source.

It's worse than that, mate. Every time you double the distance, the brightess goes down by a factor of four! So, two feet away, the bulb is a quarter as bright as it was a foot away.

Sweet

[internerdj]

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.

If they are still not dimmable they still suck

[Lumpy]

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

[gnick]

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

[Sj0]

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

[zenyu]

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.

Nope. LED fixtures on an Edison base incorporate ballasts, just like CFLs, and incandescent dimmers do not work well with any ballast. You are probably making the incorrect assumption that an incandescent dimmer just takes a sine wave with a ~ 170 V peak and outputs a sine wave with a lower peak. It would indeed be easy to create a dimmable ballast if that were the case. But instead these things just cut out portions of the wave creating all kinds of nasties on the house current. This is because it is cheaper to do, and all you need to do to dim an incandescent is to reduce it's average current consumption.

There are a number of solutions to this problem. The one that's most likely to happen is that a new type of dimmer will be created which does something sane for ballasts like reduce the peak voltage, and labeling will be created for both such dimmers and the CFL and LED light bulbs with compatible ballasts. Another solution would be to simply put the dimming entirely within the ballast itself, then the switch would just send a message to the bulb via radio or another out-of-band channel to the bulb circuitry to dim. But while this would be more efficient, this is not going to happen in today's fragmented home automation market without a government mandate, or at least the threat of a government mandate, to standardize.

PS There already are dimmable CFLs and CFL compatible dimmers, I have some in my house. They are not perfect, and both cost 2x as much as conventional CFLs and incandescent only dimmers; and there is no branding to tell the consumer they are compatible. This means you need to do a lot of frustrating web research before you buy the things. I also bought one bright LED Edison base lightbulb to satisfy my curiosity and it was both very expensive and non-dimmable.

PS2 My biggest frustration with buying lighting on the web is that no one shows you a spectral diagram of the light output of the bulbs. If there are any lighting web retailers reading this, please do this and you will win some early adopter business and appear expert in the eyes of even those who don't know what they are looking at. Use, trademark and reasonably license compatibility marks and you will make a killing.

Clap on?

[Pentomino]

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?

[ivan256]

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.

Whoopie for cold light!

[arugulatarsus]

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.

Re:Whoopie for cold light!

[evanbd]

LEDs have almost nothing to do with antennas, aside from the fact that both emit EM radiation. Specifically, there is no oscillator in the LED. The photons are a direct result of the diode band gap -- each electron-hole pair combining emits one photon with energy equal to the electron charge times the forward voltage (ie a 3V forward voltage LED emits photons with 3eV of energy, aka blue visible light). The Wikipedia page has a fuller explanation.

The reason LEDs produce weird light is that their spectrum is a sharp band, as opposed to the broad hump of a black body. This can be fixed (somewhat) by using a phophor to shift some of that frequency (most white LEDs), but the usual techniques for that leave a gap between the LED emission and the phosphor emission. Better, though more expensive, is combining enough different color LEDs that the narrow individual bands blend together to simulate the blackbody output. Eventually, that will get cheap enough to be common, and then you'll see LEDs in common usage as lighting.

British invention

[EdZ]

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

Oblig seinfeld reference

[philspear]

Lightbulbs getting out of a pool I guess.

What about the production?

[Erioll]

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?

[Idiomatick]

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?

[lagfest]

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?

[danep]

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

Re:What about the production?

[bahwi]

More mercury from coal plants used to power incandescent bulbs, 100% of it lost to the environment. Look at whole life, not just one part.

Re:What about the production?

[Khyber]

Quit buying crap CFL and just rig your place with T5HO linear fluorescent.

One 54 watt bulb is all I need to light my living room or my kitchen, and it's 5,000 lumens INSTANTLY, no warm-up.

And they grow GREAT sweet basil and catnip and peppers.

Re:What about the production?

[lawpoop]

The problem with CFLs is not the mercury spread into the environment during production, is the spot concentrations of mercury 1. in your home, when you break a bulb, and 2. in the landfill, when people toss them out like regular bulbs, not understanding that these are hazardous waste and need to be disposed of in the proper facilities.

When you break a lamp, the state of Maine says "The next time you replace a lamp, consider putting a drop cloth on the floor so that any accidental breakage can be easily cleaned up. If consumers remain concerned regarding safety, they may consider not utilizing fluorescent lamps in situations where they could easily be broken. Consumers may also consider avoiding CFL usage in bedrooms or carpeted areas frequented by infants, small children, or pregnant women. "

Here's what the EPA says to do if a CFL bulb breaks in your home:

Before Clean-up: Air Out the Room

• Have people and pets leave the room, and don't let anyone walk through the breakage area on their way out.
• Open a window and leave the room for 15 minutes or more.
• Shut off the central forced-air heating/air conditioning system, if you have one.

Clean-Up Steps for Hard Surfaces

• Carefully scoop up glass pieces and powder using stiff paper or cardboard and place them in a glass jar with metal lid (such as a canning jar) or in a sealed plastic bag.
• Use sticky tape, such as duct tape, to pick up any remaining small glass fragments and powder.
• Wipe the area clean with damp paper towels or disposable wet wipes. Place towels in the glass jar or plastic bag.
• Do not use a vacuum or broom to clean up the broken bulb on hard surfaces.

Clean-up Steps for Carpeting or Rug

• Carefully pick up glass fragments and place them in a glass jar with metal lid (such as a canning jar) or in a sealed plastic bag.
• Use sticky tape, such as duct tape, to pick up any remaining small glass fragments and powder.
• If vacuuming is needed after all visible materials are removed, vacuum the area where the bulb was broken.
• Remove the vacuum bag (or empty and wipe the canister), and put the bag or vacuum debris in a sealed plastic bag.

Clean-up Steps for Clothing, Bedding and Other Soft Materials

• If clothing or bedding materials come in direct contact with broken glass or mercury-containing powder from inside the bulb that may stick to the fabric, the clothing or bedding should be thrown away. Do not wash such clothing or bedding because mercury fragments in the clothing may contaminate the machine and/or pollute sewage.
• You can, however, wash clothing or other materials that have been exposed to the mercury vapor from a broken CFL, such as the clothing you are wearing when you cleaned up the broken CFL, as long as that clothing has not come into direct contact with the materials from the broken bulb.
• If shoes come into direct contact with broken glass or mercury-containing powder from the bulb, wipe them off with damp paper towels or disposable wet wipes. Place the towels or wipes in a glass jar or plastic bag for disposal.

Disposal of Clean-up Materials

• Immediately place all clean-up materials outdoors in a trash container or protected area for the next normal trash pickup.
• Wash your hands after disposing of the jars or plastic bags containing clean-up materials.
• Check with your local or state government about disposal requirements in your specific area. Some states do not allow such trash disposal. Instead, they require that broken and unbroken mercury-containing bulbs

Re:What about the production?

[thegameiam]

And they grow GREAT sweet basil and catnip and peppers.

Is that what the kids are calling it these days?

Re:What about the production?

[Khyber]

I'm calling bullshit.

The largest T5HO bulb only uses 54w of power, two of those would be 108, plus ballast which in reality should be far, FAR more efficient than that, should use no more than 125w of power.

My 4-lamp T5HO system uses 230w according to Kill-A-Watt, that's 216w in light bulbs plus 14w energy conversion loss in the ballast. I toss out 20,000 lumens.

Your 100w incandescent only at most pumps 12-1800 lumens.

So either you bought some bullshit lighting or you're talking out of your ass.

Re:What about the production?

[Peepsalot]

LEDs appear very bright when viewed directly for two reasons:

1) They are nearly a perfect point light source.
2) They light output is typically very directional.

But when you try to illuminate a room with one, you have to spread out this concentrated beam so much that it's not nearly as bright as your first impressions might make you think.

Re:What about the production?

[deglr6328]

BULL-fucking-SHIT. The ~3 MILLIgrams of Hg in a CFL are in an entirely inorganic metal amalgam form. Stop pulling wacky pseudoscience scare tactic shit out of your ass and claiming it as truth.

Re:What about the production?

[Entropy2016]

Inorganic mercury in the environment (wether it's by burning coal at power plants or from light bulbs) eventually reaches soils, which get wet with water, and as most of the water on land eventually does, washes into aquatic systems (water cycle).

Microorganisms in the aquatic environment then convert it to methylmercury (what he was talking about).

After that, it's the same old story you already know: Aquatic system is contaminated so the mercury (actually methylmercury) bioaccumulates its way up the food chain until it gets to the humans who eat the fish. The higher up the food chain the carnivore is, the more toxic their exposure is. This should be of personal concern to you if you are a whale, shark, big fish (like tuna) or human.

It really doesn't matter what type of mercury is in those bulbs.

All forms of it that get into the environment do eventually turn into the very type that hurts us most.

Big advancement

[rift321]

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...

Ahh, 5 years...

[PowerVegetable]

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:Solar panels too?

[giafly]

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

Re:you sir are incorrect

[nwf]

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.

Re:Are they going to be tiny?

[Anonymous Coward]

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...

We need lumens ratings

[kherr]

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.

Re:We need lumens ratings

[dr2chase]

Not so for LEDs; their peaks are substantially less sharp. I verified this both with a physicist, and with a diffraction grating. I took pictures, too. One problem you get, is that the "highest lumen" LEDs have a spectrum similar to an arc-welder, and it's not so nice. I used some good-quality neutral-white CREE LEDs for kitchen counter lighting, and it is quite nice.

Ok, let's get this thread straightened out.

[hey!]

(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.

Wrong bulbs

[camperdave]

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.

Re:Wrong bulbs

[camperdave]

Look for the words "Instant on" on the packaging. I'll post the exact make/model info when I get home later today.

Gallium is NOT in short supply

[geekoid]

Never has been, and probably never will be.

Indium and Gallium Sustainability â" September 2007 Update

Re:Retina Sear

[fireman sam]

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.