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From The Fine Article;

... ultimately improved the efficiency of the bulb to 6.6% ...

6.6% is 45 lumens per watt.
Pardon me while I yawn.
This tech might lead to something interesting, but so far, not so much.

The commercially available Cree soft white 4-flow A19 bulb is 12% or 82 lumens per watt.

There are LED modules for sale that are over 200 lumens per watt.

In the lab, 303 lumens per watt (44%) has been achieved.

From The Fine Article;

... ultimately improved the efficiency of the bulb to 6.6% ...

6.6% is 45 lumens per watt.
Pardon me while I yawn.
This tech might lead to something interesting, but so far, not so much.

The commercially available Cree soft white 4-flow A19 bulb is 12% or 82 lumens per watt.

There are LED modules for sale that are over 200 lumens per watt.

In the lab, 303 lumens per watt (44%) has been achieved.

Actually, 420 would be a bit too violet for this application. Cree's XR-E emitters seem to use a blue emitter centered around 450nm (pdf), coupled with a yellow phosphor -- blue + yellow = blue + (green + red) = white. That's how most "white" LEDs work. If you used a shorter-wavelength emitter, you'd need to downconvert all its output power, losing efficiency. By using a blue emitter, you pass some of the blue light, and downconvert just enough of it to yield the perceived color temperature you want.

Err - no.

That number on the Digikey page isn't lumens per watt (I've no idea what unit mw/W is supposed to be).

If you look at the datasheet that LED is a max of 139 lumens with a forward voltage drop of 2.9 at 350 mA, or slightly less than 140 lumens per watt (under ideal conditions).

By definition there are 683 lumens per watt of radiant power at a wavelength of 555 nm.

The highest announced efficiency LED to date is "only" 303 lumens per watt - http://cree.com/News-and-Events/Cree-News/Press-Releases/2014/March/300LPW-LED-barrier
303/683 = 0.44 or 44%

The best LED I can actually buy is still under 200 lumens per watt, less than 30%

The 4flow, which is pretty close to the best consumer LED light bulb you can get is only 85 lumens per watt.
http://www.homedepot.com/p/Cree-60W-Equivalent-Soft-White-2700K-A19-Dimmable-LED-Light-Bulb-with-4Flow-Filament-Design-BA19-08027OMF-12DE26-3U100/205597078

All much better (efficacy) than a CFL or incandescent, but no where near 48%

Because the PIV rating of LEDS will not withstand anything even close to full mains voltage. They are not constructed as rectifiers, even though they are technically diodes. This datasheet shows the max PIV for a high performance white LED to be a mere 5V! A typical 1N4007 rectifier diode is rated for 1000V PIV DC.

That was a demonstration only and the junction temperature was an unrealistic 25 C, not 85 C, and the efficiency of the driver circuit is not included in the laboratory results. Maybe the process to produce the sample is phenomenally expensive, and maybe they had to pick through thousands of units to find one that hit the mark. Because how else do you explain that the Crees you can buy in the store only produce a piss poor 84 lumens per watt? Do they purposely market obsolete shit because they know they can get away with marketing obsolete shit, or are there possibly actual engineering and economic reasons they can't sell the good stuff?

Light.

And who doesn't like anything that brings light?

Cree's official indoor lighting FAQ still states outright:
"Our lamps are designed for open air and semi-enclosed housings, but not recommended for fully enclosed housings."

Sodium lights get 140 lumens per watt

Strange that you went out of your way to say this, yet failing to note that there's a huge difference between low-pressure sodium and high-pressure sodium, and also not mentioning the efficiency of LEDs.

In-the-lab, LEDs are the most efficient form of electric lighting, demonstrated at 254 lumens/watt last year... better than HPS, better than LPS, and better than any others. The efficiency you'll get with inexpensive retail bulbs is significantly lower, though bulbs based on moderately expensive emitters (like a Cree XM-L2 U3) can exceed 150lm/watt.

http://www.cree.com/news-and-events/cree-news/press-releases/2012/april/120412-254-lumen-per-watt

http://www.cree.com/led-components-and-modules/products/xlamp/discrete-directional/~/media/Files/Cree/LED%20Components%20and%20Modules/XLamp/Data%20and%20Binning/XLampXML2.pdf

Sodium lights get 140 lumens per watt

Strange that you went out of your way to say this, yet failing to note that there's a huge difference between low-pressure sodium and high-pressure sodium, and also not mentioning the efficiency of LEDs.

In-the-lab, LEDs are the most efficient form of electric lighting, demonstrated at 254 lumens/watt last year... better than HPS, better than LPS, and better than any others. The efficiency you'll get with inexpensive retail bulbs is significantly lower, though bulbs based on moderately expensive emitters (like a Cree XM-L2 U3) can exceed 150lm/watt.

http://www.cree.com/news-and-events/cree-news/press-releases/2012/april/120412-254-lumen-per-watt

http://www.cree.com/led-components-and-modules/products/xlamp/discrete-directional/~/media/Files/Cree/LED%20Components%20and%20Modules/XLamp/Data%20and%20Binning/XLampXML2.pdf

Yes, it's you - you are so last year.

We aren't talking about those cheap $10 bulbs from Home Depot that get a measly 84 lumens/watt.

Commercially available LED street lights like Cree's LEDway have been over 100 lumens / watt since 2013-03, making them more efficient than high pressure sodium even without considering their arguably superior focusing and CRI.

I agree with your points. It's interesting to note that the cost of an LED bulb that goes in an old fixture is similar to, or more expensive than, a brand-new fixture with LEDs built in!

When you design a fixture as an LED fixture, you can design it to dissipate the heat. The whole exterior of the fixture can be used as a heat sink to put heat out into the room (i.e. get it away from the LED chips). But when you design a backward-compatible bulb, you must pack those chips in a small space, and you need to put in a lot of them in all different directions. So you need a carefully-engineered design, which packs a lot of LED chips in a small space yet keeps them cool.

It's clearly better to have all the LEDs pointing in the direction you want the light to go, but old incandescent fixtures often have the bulb on its side with a reflector above it. So the carefully-engineered LED bulb that shines in all directions is now working to bounce light off a reflector, rather than just have all the LEDs shine where you want the light.

You can already buy a "can light" replacement, the Cree LR6, that has a decorative bezel that helps serve as a heat sink. It's easy to install too. I had a single can light in my home and I have already installed one of these; I love it.

So "can lights" are a solved problem, but normal light bulb fixtures are harder.

You can buy fixtures now with soldered-in LED chips. And they should last two decades, which isn't bad. But I'd like to see a standardized modular design, where power supply is one modular piece and the LEDs are mounted on another (designed to work as a heat sink). This would solve the problem someone noted, that two decades from now the fixtures you bought may no longer be made, and replacing them one at a time won't look ideally pretty.

... it's a UV diode with a phosphor on it, not a blue diode.

Nope. Just look at the spectrum of some white LEDs, they clearly peak around 450 nm plus what the phosphor delivers. UV is very problematic as it quickly degrades the plastic optics which are predominantly used with LEDs. Plus, you would only get the yellow light from the phosphor, not white light. It's the mixture of blue and yellow that's necessary where the ratio determines the correlated color temperature.
E.g.: http://www.cree.com/led-components-and-modules/products/xlamp/discrete-directional/~/media/Files/Cree/LED%20Components%20and%20Modules/XLamp/Data%20and%20Binning/XLampXPG2.pdf

LEDs of all types (lasers excluded) have no "spike". Typical half-power bandwidth is 20 nm. It's not smooth enough for color comparisons of paint or makeup, but it's nowhere near the monochromatic implied by "spike".

Since we're talking about cree lights check out their data sheets on their own LED lighting products. The graph on pg5 looks like a spike to me.

http://www.cree.com/~/media/Files/Cree/LED%20Components%20and%20Modules/XLamp/Data%20and%20Binning/XLamp7090XRE.pdf

Cree publishes the wavelength distribution for the different colour temps of MK-R:

http://www.cree.com/led-components-and-modules/products/xlamp/arrays-directional/~/media/Files/Cree/LED%20Components%20and%20Modules/XLamp/Data%20and%20Binning/XLampMKR.pdf

They don't look terribly useful for anything like image projection, but they'd be fine for a flashlight.

Of note is that they only hit 200 lumens per watt at 1W. If you crank it up to 15 W, they'll do 1769 lumens, which is only 118 lumens per watt. That's still an improvement over their previous best, the XM-L, which did 1040 lumens at 10 W, but it still means that if you want to maintain that 200 lumens per watt, you're going to need a bunch of LEDs to hit higher brightnesses.

I'm not sure how combining the warm, neutral and cool LEDs would accomplish much. If you look at the relative spectral power distribution plot in the Cree datasheet, you'll see that all three bulb types pretty much overlap in their spectra. They just have different relative powers in the blue and yellow peaks. Warm, neutral, and cool spectra all have that large gap centered at 480 nm, and they all have little power towards the red end. Therefore, combining the three bulb types would not "fill in" any missing part of the spectrum, just change the yellow/blue balance.

Also, I don't see how that demonstration proves anything. What you see on your monitor is vastly different from what your eyes would percieve if you were standing at the scene. And while you're right that the eye can adapt somewhat, that's only true to a certain extent. There's no way you can adapt to that gap at 480 nm, for instance. If an object is reflective at that colour, and it is illuminated with a phosphor LED, then that object will appear darker than it should, no matter what. Your eye can't compensate for such spectral "notches".

I've got lights like that myself. But XM-L emitters peak at about 100 lumens/watt, not the 200 lumens/watt promised by this new technology.

Also, none of these lights really do put out the amounts of light that the emitters are rated at. For example, this says 1600 lumens, but I'll bet it's more like 800 lumens. Still, not too bad, and yes, good lights make a huge difference, and it's hard to beat the price.

Cree has this page crowing about one of their their CXA series modules being 108 lm/W at 85c and 119 lm/W at 25c. I haven't found anything higher. Here's the datasheet.

Cree has this page crowing about one of their their CXA series modules being 108 lm/W at 85c and 119 lm/W at 25c. I haven't found anything higher. Here's the datasheet.

Makes me wonder why Cree hasn't released a light bulb yet.

They have http://www.cree.com/lighting/products/

Any good LED lighting solution is intelligent: they talk to each other and drop to 20% lighting when there's no roadway activity, then go back to full power when the next one over detects a car coming along. (At least, that's what my company, and the competitors I know about, are building for the outdoor area lighting market.) Also, Cree's over 230 lumens per watt experimentally.

And as they stated, the LEDs are bright enough.. WTF we need lasers?

Among other things, laser light is a lot more energy efficient. According to the article, BMW is getting 170 lumens per watt as compared to 100 lumens per watt for LED lights.

They're using older numbers for LED's. Cree's at 231 lumens per watt. They hit 200 lumens/watt in 2010, and 170 back in 2008. The 100 lumens/watt numbers are likely accurate for currently-available LEDs and more specifically the packaging that is required for automotive environments (wide temp range, high reliability, vibration-withstanding ability) but higher-efficiency LED's will be qualifying for that within a couple years.

cree says they have 160lm per watt leds. http://www.cree.com/press/press_detail.asp?i=1271079100891

Yes! CFLs suck! Which is why we should all be transitioning to LED lighting. There are finally some high-quality solutions on the market, which despite their high pricetags will save 2-3x the purchase price in energy over their 10-year life. I now have five of the CREE LR6 recessed fixtures in my house and they are incredible--bright light, very nice color (with active color adjustment, no less), instant-on, and 10-20 year life. And they only use about 7 watts to match a 60-watt incandescent.

I also have eight LED replacement tubes from a random place in China. I know they seem kinda sketchy, but their tubes are the best quality I've found anywhere and they do actually ship pretty quickly.

CREE has a whitepaper detailing how LEDs are so much better than CFLs, both in quality and environmental impact. I hope they catch on and people stop equating energy-saving with crappy CFLs.

Light output - total light output, not how bright a spot it can make on a wall - is measured in lumens.

The bulb above - look at the box shot - says 450lm for 6.9W.

That's 65lm/W - this is very close to the 60lm/W that most of my CFLs claim.

It's significantly below the 100lm/W that you get from linear flourescants.

The best LEDs at the moment get around 114lm/W - http://www.cree.com/products/xlamp_xpe.asp - and ones sampling now from the same maker get 140. It's not possible to get more than maybe 300 - as then you're getting close to the fundamental amount of power needed to make a watt of wite light.

I did a basic design for a 100lm/W lamp - from AC to replace 100W of lightbulbs.
It needed 15 1W LEDs, a high efficiency supply, and would cost perhaps $60 in bulk.

If you drive the LEDs harder, you can use half the number, and get about 2/3 the efficiency, and maybe $40 cost.

This was for relatively small numbers.

And, additional, because I'm stupid and hit 'submit' rather than preview,
Cree announces 161 lumens/watt in a high-power R&D white LED.
This is in the range where it's viable for LED's to compete in every market with CFL's, particularly ones involving rapid cycling (bathrooms, refrigerators) and ones that *could* involve rapid cycling but traditionally haven't (security lights, parking lot illumination.)

The City of Raleigh has been partnered with Cree for over a year in rolling out LED lighting for parking structures and streets.

http://www.cree.com/press/press_detail.asp?i=1171295242023

Chip H.

Bullshit. This applies to very cheap LED's bought from China (or similar). Leading manufacturers like Cree, Lumileds and the rest claim 75% of lumen maintenance after 50'000 hours.

I'm not sure where you got your numbers from, but LEDs have made some major leaps and bounds in the past few years. CREE claims 50-80 lumens/watt in their production power LEDs http://www.cree.com/products/xlamp.asp, and as high as 100 with experimental designs.
Osram recently announced a 1000 lumen LED (really 6 LED dies packed into one device) that will be sent to market this summer. http://www.physorg.com/news93198212.html

Carbon trades at $3.75/ton on the Chicago Climate Exchange http://www.chicagoclimatex.com/. They don't do an avoided emissions credit but they are working on it. For a CFL that replaces a 60 W incadescent at 13 W and lasts for 7 years with 4 hours of use per day the avoided electric use is 0.49 MWh and so using the low conversion rate that the exchange uses for renewable electric power http://www.chicagoclimatex.com/news/publications/p df/CCX_Renewable_Offsets.pdf based on displacing gas turbines this comes to 0.18 ton of carbon, or $0.74.

You can get CFLs for 1.89 bulk retail http://www.1000bulbs.com/products.php?cat=13-Watt- Compact-Fluorescents so just the carbon savings are likely coming close to the cost of production.

At $0.09 per kWh electric cost, one also saves $44 per bulb.

So, why would legislation be needed? I think mainly to get people thinking.

LED street lights are begining to get going with a similar boost in efficiency and greater reliablility http://www.cree.com/press/press_detail.asp?i=11712 95242023.
--
Switch to solar: http://mdsolar.blogspot.com/2007/01/slashdot-users -selling-solar.html

Compact fluorescents, 50-70 lumens per watt off the shelf.

White LEDs, 30-45 lumens per watt off the shelf, 131 in the lab. And way more expensive.

http://www.netl.doe.gov/ssl/faqs.htm
http://www.cree.com/press/press_detail.asp?i=11508 34953712
http://members.misty.com/don/lede.html

Right now the reason to use LEDs is if the environment is harsh (vibrations, impacts, etc.) or if you really, really don't want to change the light often (traffic lights, or that %^#@!! bulb over my stairs). LEDs also scale down better than anything else.

You don't need a breakthrough, just a continuation of the high-speed progress of the last few years.

Compact fluorescents are 50+ lumens per watt, with 75 being really good. Last year, the pre-production state of the art was 131 lumens per watt in a white LED. LEDs were shipping (mass production) at 40 lumens per watt in 2004 and are now more like 60.

The cost of LEDs is crashing. The bulb over my stairs which I paid $32 for is now available for $12. A compact fluorescent is more cost-effective today, but if the bulb is difficult or dangerous to change then an LED is already the right choice.

Cree just announced an LED with an efficiency of 131 luments per watt (compared to incandescent light bulbs at 10 to 20 lumens per watt range, and compact fluorescent lamps range from 50 to 60 lumens per watt).

So they are coming. Then again, Cree seems to have a history of "science by press release", where they announce these amazing specs, then never bring the product to market.

LEDs are certainly better than flashlight bulbs.

But when a white LED delivers 15-19 lumens per watt, its about the same as a 100W incandescent and five times worse than a fluorescent.

Cree are claiming a white (phosphor-based) LED with 50% wallplug efficiency, according to Don Klipstein's Lighting Site. The link from his site is dead, though. Cree are also claiming that lab versions of a current LED achieve 70 lumens/watt, and a total of 85 lumens at 350 mA. You'd still need about 25 of these to get the light output of a 100W incandescent, though. Probably cheaper to drop 300 5mm LEDs into a dedicated fixture - Chi Wing's eBay store will sell you 300 16,000 mcd (maybe...) white LEDs for a little over $100, shipped. However, I can't really see spending $100 for a 100W bulb, ya know?

OTGH, though, I can see a distinctly untapped market for specialty, artistic LED fixtures that simply can't be realized with incandescents or fluorescents.

Cree are claiming a white (phosphor-based) LED with 50% wallplug efficiency, according to Don Klipstein's Lighting Site. The link from his site is dead, though. Cree are also claiming that lab versions of a current LED achieve 70 lumens/watt, and a total of 85 lumens at 350 mA. You'd still need about 25 of these to get the light output of a 100W incandescent, though. Probably cheaper to drop 300 5mm LEDs into a dedicated fixture - Chi Wing's eBay store will sell you 300 16,000 mcd (maybe...) white LEDs for a little over $100, shipped. However, I can't really see spending $100 for a 100W bulb, ya know?

OTGH, though, I can see a distinctly untapped market for specialty, artistic LED fixtures that simply can't be realized with incandescents or fluorescents.

I don't understand the distinction between what this group has done and what you can buy today from companies like cree. You can today buy high-temp silicon carbide products. Is this article about a new way to make SiC wafers?

Silicon Carbide does work -- Cree, Inc. of Durham, NC has been manufacturing electronics (particularly blue LEDs) for years using silicon carbide as the substrate. The technology was developed at NC State University, as I recall.

Cree Research makes 'em.

Pretty nifty site.

For more info you can check out CREE's website They are a huge LED manufacture.