Beta

Slashdot: News for Nerds

×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

Cree Introduces 200 Lumen/Watt Production Power LEDs

timothy posted about a year and a half ago | from the want-some-dagnabbit-super-lights dept.

News 421

ndverdo writes "Cree just announced production power LEDs reaching 200 lumen/watt. Approximately doubling the previous peak LED light efficiency, the new LEDs will require less cooling. This should enable the MK-R series to finally provide direct no-hassle replacements to popular form-factors such as MR-16 spots and incandescent lighting in general. The LEDs are sampling and it is stated that 'production quantities are available with standard lead times.'"

cancel ×

421 comments

These Cree guys are really bright. (5, Funny)

Anonymous Coward | about a year and a half ago | (#42424065)

Kudos.

Re:These Cree guys are really bright. (0)

Osgeld (1900440) | about a year and a half ago | (#42424123)

heh

Re:These Cree guys are really bright. (3, Insightful)

Nom du Keyboard (633989) | about a year and a half ago | (#42424693)

Price?

Slashvertisment (0, Offtopic)

Anonymous Coward | about a year and a half ago | (#42424067)

Yay, another slashvertisment.

Re:Slashvertisment (5, Insightful)

Anonymous Coward | about a year and a half ago | (#42424347)

While it indeed is a commercial product, it's also a new industry milestone.

Cooling is the issue (4, Interesting)

calidoscope (312571) | about a year and a half ago | (#42424069)

The reduced cooling should help in lowering the costs of the LED versus the CFL and the reduced energy consumption will be a help as well.

Re:Cooling is the issue (5, Interesting)

falconwolf (725481) | about a year and a half ago | (#42424171)

The reduced cooling should help in lowering the costs of the LED versus the CFL and the reduced energy consumption will be a help as well.

Yesterday I went to Walmart to get new light bulbs, old CFLs I had burned out. There Walmart had LED bulbs in stock, at around $20 a bulb. I ended up going to Sam's to get CFLs, an 8 pack cost less than $6.

Falcon

Re:Cooling is the issue (2)

aliquis (678370) | about a year and a half ago | (#42424217)

I don't know how it helps or interest someone else but I paid the equivalent of less than $10 for my 650 lumen ones but that was only because they was half price and when I bought it the half price was already in the register but the person selling them also pushed in 50% off so hence I only paid 25% of the original price. And I had actually looked at them at full price earlier because CFLs die so quickly at the toilet and bathroom.

I also bought 12v spotlights with LED. I wonder if I got the same price there but I kinda think I did. Possibly only half price. I have four of them in the ceiling in the living room and while expensive running that lamp normally used 4*25 watt + whatever losses the transformer have and that should be 4*6.7 or something such now. Also the halogen spotlights are rated at 1,000h life-time I think and die pretty quickly while these are 20,000h or 25,000h + spotlights are more expensive than regular lightbulbs to begin with. So even if they are expensive at 20 times longer life time they doesn't cost 20 times more. Just a higher up-front cost.

But then again prices will go down in the future. But I figured if no-one buy them now progress will take a longer time.

Re:Cooling is the issue (1)

nabsltd (1313397) | about a year and a half ago | (#42424411)

And I had actually looked at them at full price earlier because CFLs die so quickly at the toilet and bathroom.

I have had 4 CFL globes in my bathroom for nearly 4 years, and have replaced only one bulb so far. In general, CFLs seem to have a worst case of about 5-6 times the life of an incandescent in the same fixture. I also like the fact that I can get more light when the fixture is wattage/heat limited.

Other than not being able to use dimmers, the biggest complaint I have with CFLs is that now it's tough to buy just one or two without paying a huge premium. The multi-bulb packs are sometimes so much cheaper per bulb that it's often worth it to just buy the pack. But, since they don't burn out very quickly, I end up with a fairly large collection of each type of bulb.

Re:Cooling is the issue (5, Informative)

aliquis (678370) | about a year and a half ago | (#42424485)

It depend on the quality of the bulb.

Many are listed at 10,000 (or 8,000?) on-off cycles.

Osram Dulux intelligent longlife for instance is rated at 500,000 on-off cycles.

Sure it will cost more than the very cheapest CFLs but it's 5 or so times more, not 50 times more. And that's more than my LED lights are rated at (the ones I bought it's even highly rated.)

Regarding the rating and heat I think it make total sense to at least be able to put a similar power rated light-bulb in the same fixture considering the higher efficiency. I'm not 100% sure it work like that but I can't understand why it shouldn't. Using LEDs those cooling fins get hot but then again a regular lightbulb get very hot to.

You can get CFLs usable with dimmers to. I think what people should take home with them is that you should buy the CFL which fit your needs, not just any CFL. If it's going to be on for long sure buying any may be ok. If it's going to go on and off often buy one for that, if it need to be dimmable buy one for that and if it will be sitting outside like here and may have a -20 degree C around it buy one designed for that.

Re:Cooling is the issue (1)

Airline_Sickness_Bag (111686) | about a year and a half ago | (#42424561)

Bought 10 CFL bulbs for my kitchen. They all died in less than a year.

Re:Cooling is the issue (0)

Anonymous Coward | about a year and a half ago | (#42424613)

You should look into causes then, not just rail over the symptom. I haven't had a CFL fail in years, but I know my wiring is good, my switches are quality and the sockets properly installed.

Maybe you think fixing those things might be expensive. So might the electrical fire because you chose the cheap route.

Re:Cooling is the issue (0)

Anonymous Coward | about a year and a half ago | (#42424403)

I found this useful if accurate [designrecycleinc.com] .75/bulb versus $20 is huge. Some factors close the in on the gap but may not quite get there. An LCD will last over 6 times longer and use half as much energy. Don't know if the electricity saved and lifespan make up the difference though. Maybe in a high humidity area like the bathroom or hot climates where the lower temperature would help keep cooling costs down. Lot of factors.

Re:Cooling is the issue (0)

Anonymous Coward | about a year and a half ago | (#42424449)

Just about every light in my house for the last 10 years is a CFL and a few T5 tube bulbs. I've noticed the LED lights slowly coming down in price but it still does not seem worth it yet. I did by a dual head LED motion sensing spotlight from Costco this summer for my yard. It was only $59. At that price, it was in the range of mid level quality outdoor security lights but has the advantage of being at full brightness immediately. My older security light with screw in CFL floodlights took way too long in the winter to get bright enough.

Re:Cooling is the issue (1)

pwizard2 (920421) | about a year and a half ago | (#42424265)

For me, CFLs have worked fine for years but I wish they would make giant LEDs you could screw in like regular light bulbs. Maybe LED technology doesn't work if you scale it up that much, I don't know for sure b/c it isn't my area of expertise. At least they have warmer color temperatures for white LEDs now.

Re:Cooling is the issue (0)

Anonymous Coward | about a year and a half ago | (#42424471)

They do make such bulbs using the Edison base. I have several in my house. Most in recessed fixtures or the corner floodlights, but a few that I have used as basic bulb replacements.

The Phillips one is nice. Ugly Yellow when off, but how much time should I spend looking at bulbs that I've turned off?

Re:Cooling is the issue (5, Informative)

Anonymous Psychopath (18031) | about a year and a half ago | (#42424501)

I have Cree bulbs in my 4" recessed lights. They put out a warm color, don't make any noise, and work fine on a dimmer. I honestly can't tell the difference between them and the halogens they replaced, except they run a lot cooler. They sell them at Home Depot for about $40 each. I expect them to last at least ten years. The Cree guys know what they're doing.

Re:Cooling is the issue (3, Informative)

dougmc (70836) | about a year and a half ago | (#42424273)

If you double the efficiency, you *more* than half the cooling needed for a given amount of light.

To give an example with some math ...

Suppose you need 2000 lumens from a 100 lumen/watt bulb. That means it takes 20 watts of power, and puts out 18 watts of heat.

Replace it with a 200 lumen/watt emitter that has the same light output, and it now needs only 10 watts of power, and only puts out 8 watts of heat.

All that said, I'm looking forward to this being available for bicycle lights. Doubling the efficiency means I can have double the light with the same sized battery pack, or the same amount of light with half the battery pack or some permutation thereof. Cooling isn't a big deal for bicycle lights until you get into the really high powered lights as the airflow is usually quite good.

Re:Cooling is the issue (0)

Anonymous Coward | about a year and a half ago | (#42424455)

>All that said, I'm looking forward to this being available for bicycle lights.

Its here already with the last LED model (the XM-L, just a small step down): http://www.amazon.com/gp/product/B00A3MY7FO/ref=oh_details_o01_s00_i00
I don't imagine that you could build a 1000+ lumen light/batter/charger combo for cheaper if you tried.

I can vouch that it is of decent enough quality and a ton of light for the price. I'm amazed by how cars treat me differently when I'm shining a car headlight-equivalent back at them.

Re:Cooling is the issue (1)

dougmc (70836) | about a year and a half ago | (#42424505)

I've got lights like that myself. But XM-L emitters peak at about 100 lumens/watt [cree.com] , 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.

Re:Cooling is the issue (4, Insightful)

symbolset (646467) | about a year and a half ago | (#42424473)

These are surface mount LED modules, not bulbs. I checked one out [newark.com] . At 700 mA @12V (8.4W) gives 1040 lumens - approximately as much as a 70-watt incandescent - in a square 7mm on a side. This is only 123 lumens per watt. Max current is 1250 mA, so you could conceivably get a lot more light out of one, and presumably 1W is where the 200 Lumens/W kicks in, but that's only about a 25W incandescent equivalent - still pretty respectable considering the size. They cost about $10 in quantity 500. ROI is about 6 months vs. incandescent, or 18 months at the 200 lumens/W level.

I think I could see some interesting applications for this one. At 1040 lumens 18% of the electrical energy is converted to light, so around 6.9 W of heat. It's also too bright to look directly at.

Yes, it's a slashvertisement / press release. But LED lighting has /. common interests energy, technology, and so on. Progress is progress.

If they can just improve the efficiency a little more these might be interesting not only as a light source but as a means for spacecraft propulsion.

Re:Cooling is the issue (1, Funny)

fotoguzzi (230256) | about a year and a half ago | (#42424661)

Incandescent bulbs will scorch one's fingers. What part of the led or circuitry is so sensitive to heat that cooling is such an issue for led bubs? Would placing the circuitry in a vacuum help at all?

Just hurry up! (0)

Anonymous Coward | about a year and a half ago | (#42424075)

I've had many other LED "bulbs" fail.

these are not the bulbs you are looking for (1)

rubycodez (864176) | about a year and a half ago | (#42424131)

these are suitable for directional applications only, not a replacement for the common light bulb. just like every other LED light to date, just not quite right

Re:these are not the bulbs you are looking for (2)

Jaime2 (824950) | about a year and a half ago | (#42424189)

It won't be long before companies figure out how to get them to work. The Phillips L-Prize bulb uses the LED as a source of photons to excite a phosphorescent material. The actual light that the bulb emits comes from the outer surface of the bulb, so directionality of the LED is irrelevant, as long as they can excite enough of the phosphor.

what? (1)

ArchieBunker (132337) | about a year and a half ago | (#42424305)

There is nothing to figure out. Its a problem of physics. LEDs produce heat that must be dissipated somehow. Its no good if your replacement bulb has a huge heatsink attached to it. It also brings up the problem of lights in enclosed spaces, something incandescents have no issue with.

Re:what? (0)

Anonymous Coward | about a year and a half ago | (#42424419)

LEDs produce very little heat compared to alternatives. Something like 1/10 what a CFL uses and even less compared to an incandescent.

Re:these are not the bulbs you are looking for (1)

Anonymous Coward | about a year and a half ago | (#42424539)

All white LEDs are blue LEDs with a yellow phosphor. RGB doesn't emit a good spectrum for general illumination.

Re:these are not the bulbs you are looking for (1)

aaarrrgggh (9205) | about a year and a half ago | (#42424263)

The hell are you smoking?! A highly directional source is much more desirable to an "A" (as in arbitrary) lamp. Optics for a good point source are much easier to design than a linear source.

At 200 lumens/Watt (assume 160 as a system), this is huge. It makes a whole lot of retrofit applications viable.

Wonder what year OLEDs will hit this level.

Re:these are not the bulbs you are looking for (1)

harlequinn (909271) | about a year and a half ago | (#42424397)

At 200 lumens/Watt (assume 160 as a system), this is huge. It makes a whole lot of retrofit applications viable.

The current market leader, the Cree XM-L does 160 lumens per watt. So this is a 25% increase.

At 160 lumens/watt the XM-L is already way more efficient than fluorescent, HID, halogen incandescents, etc. Yet the industry still hasn't gone ahead to retrofit/adapt this to existing applications. I don't think this newer Cree MK-R is going to change the rate of adoption that much - the only industry that jumps on LED advancements is the torch industry.

Re:these are not the bulbs you are looking for (1)

harlequinn (909271) | about a year and a half ago | (#42424425)

Note: this Cree MK-R isn't super suitable for torches - it's a multi-chip design that supersedes the MC-E and runs around 11 to 12 volts.

Re:these are not the bulbs you are looking for (5, Funny)

killkillkill (884238) | about a year and a half ago | (#42424611)

this Cree MK-R isn't super suitable for torches

Certainly not suitable. It produces less heat than other LEDs, which are themselves not even suitable. For my torches i tend to stick to propane, MAPP, and acetylene.

Re:Just hurry up! (1)

PNutts (199112) | about a year and a half ago | (#42424145)

Wrong installation? I've stayed away from the dirt cheap bulbs and haven't had an issue with LED lights yet.

Re:Just hurry up! (2)

aliquis (678370) | about a year and a half ago | (#42424233)

Obvious issues are quality of the light.

(Nothing of the following is about quality though:)

I have a very bright and 300+ lights christmas uhm.. "thread of lights" but I also use one of those older with small regular bulbs and those burn at a much much much yellower color so they look very miss-matching (the LED one is more "snow-white."

Also at the beginning the 3000k led spotlights I bought was rather disturbing because I wasn't very comfortable with the light color then but now I've got adjusted to it and don't think about it on day to day basis.

Re:Just hurry up! (1)

mrchaotica (681592) | about a year and a half ago | (#42424703)

They're making "warm white" LED Christmas lights now... but I like my "cool white" ones better anyway because my icicle lights look more like icicles that way.

I am sick and tired... (-1, Offtopic)

Anonymous Coward | about a year and a half ago | (#42424089)

of the government banning perfectly good items, like inefficient lightbulbs and high-flow showerheads and toilets. Why not put an excise tax on them instead to discourage use?

Re:I am sick and tired... (1)

kidphoton (575170) | about a year and a half ago | (#42424149)

What's inefficient? My house needs both light and heat. 100% efficiency as far as I'm concerned.

Re:I am sick and tired... (1)

Anonymous Coward | about a year and a half ago | (#42424201)

"100% efficiency as far as I'm concerned"...the other option is a lower wattage/same brightness light bulb that is still 100% efficient and using a lot less electricity to operate a heat pump that is 350% efficient. 350% is better than 100%.

Re:I am sick and tired... (1)

kidphoton (575170) | about a year and a half ago | (#42424289)

OK. Let me know when you want to install that heat pump, and I'll start bitching about the inefficiency of light bulbs. Until then, they are just as efficient as the electric furnace I can't afford to replace.

Re:I am sick and tired... (0)

Anonymous Coward | about a year and a half ago | (#42424519)

And now we have the plight of poverty writ large. You're spending a load of money because you're too poor to have the opportunity spend the money to save you money.

If the stimulus had been more invested in things like insulating people's houses or replacining ineffieficent heating/cooling, we'd be better off.

I just wish I could get a heat pump water heater, but mine is in a conditioned space, so I'd have to relocate it, and my house just doesn't have any such place where I can put the pipe.

Re:I am sick and tired... (0)

GNUALMAFUERTE (697061) | about a year and a half ago | (#42424689)

Wow. 100% efficiency? And 350% too?

Please, let us know when you will start producing free energy for the entire world.

Re:I am sick and tired... (1)

aliquis (678370) | about a year and a half ago | (#42424241)

But they will be less efficient than heat-pumps even if you use electricity for heating and in my case I live in an appartment in Sweden and as such I've got long-distance heating which is very efficient and like in VÃsterÃ¥s they are builing one huge one which will run on garbage (of which half(?) will even have to be imported.)

Though. Came to think about it one can produce electricity like that to. And they do. That's kinda what they actually do. They produce electricity and the steam is cold down using "a series of tubes" running to peoples homes :)

Re:I am sick and tired... (1)

erice (13380) | about a year and a half ago | (#42424293)

What's inefficient? My house needs both light and heat. 100% efficiency as far as I'm concerned.

Yes, but for *heat*, 100% efficiency from an electrical source is not the end. Any heat not supplied by lighting can be made up for with a heat pump ( > 100% efficiency) or direct heating from fossil fuel ( saves the losses in converting heat to mechanical energy and then to electrical energy). Waste heat from industrial uses can sometimes be used to. It's not hot enough for effective power generation but it is enough to heat a house.

Re:I am sick and tired... (1)

WaffleMonster (969671) | about a year and a half ago | (#42424515)

What's inefficient? My house needs both light and heat. 100% efficiency as far as I'm concerned

Gas heat is at least 300% cheaper than electricty.

Re:I am sick and tired... (1)

kidphoton (575170) | about a year and a half ago | (#42424577)

So if I install a gas furnace and start hauling tanks in every month (I'm out in the sticks), someone will pay me twice what I'm paying now for heating? Cool. Sign me up.

Re:I am sick and tired... (1)

Mashiki (184564) | about a year and a half ago | (#42424641)

Gas heat is at least 300% cheaper than electricty.

Unless you're already using the lighting for a particular purpose. Than that "waste heat" is already going towards the heating, which is the parents point, and mine. In Canada this is the case as well. CFL's are nice and all, but regular incandescents help with general heating costs here in the winter when you're already in a room doing something.

Re:I am sick and tired... (5, Funny)

pla (258480) | about a year and a half ago | (#42424213)

I am sick and tired... of the government banning perfectly good items

Then consider yourself in luck! Because, y'know, TFA has nothing to do with anyone banning anything. Don't let me interrupt a good rant, though - Carry on, good sir, you rage against that machine!

Some of us would rather spend our money on more fun things than literally "keeping the lights on". Do whatever you want with your money.

Re:I am sick and tired... (1)

Kohath (38547) | about a year and a half ago | (#42424479)

Do whatever you want with your money.

I think he wishes he had the choice to do that. But he doesn't, because that choice was taken from him by government do-gooders and the Federal electron police.

Re:I am sick and tired... (0)

Anonymous Coward | about a year and a half ago | (#42424675)

Boo hoo. Would he like a sponge or a cup?

Re:I am sick and tired... (2)

epyT-R (613989) | about a year and a half ago | (#42424229)

How about letting people use the energy and resources they buy as they choose, instead of punishing them for it?

Re:I am sick and tired... (0)

Anonymous Coward | about a year and a half ago | (#42424257)

No.

If you like the rules, by all means, go out and live outside of society.

Re:I am sick and tired... (0)

Anonymous Coward | about a year and a half ago | (#42424307)

I'm all for that - as long as you pay for that 100 watt/hour for your lamp - while I'm using only 5 watt/hour with my
LED light bulb.

Re:I am sick and tired... (1)

jones_supa (887896) | about a year and a half ago | (#42424401)

And where did that "/hour" come from? The power that flows through a 5 watt lamp is 5 watt even if you run it for an hour or a microsecond.

Re:I am sick and tired... (0)

Anonymous Coward | about a year and a half ago | (#42424645)

Electricity is typically billed in kilowatt-hours (kWh). [wikipedia.org] He obviously meant watt-hours instead of watt/hour. It's an easy enough mistake to make.

Re:I am sick and tired... (0)

Anonymous Coward | about a year and a half ago | (#42424513)

Poster #42424089 here. (And by doing this I'm probably making a trail to identify some of my A.C. posts, but oh well.)

I wasn't trolling. The article is mentioning LEDs ... at a time when 75 watt incandescents are being phased out.

Yes, it is sort of a rant though given that I am not too happy about the government banning things instead of putting an excise tax on them. An excise tax doesn't have to be reasonable either. It can be $5 per bulb for all I care, as long as that option still remains for those who need those "inefficient" bulbs. Personally, I use CFLs, except in the bathroom (heat and humidty I guess took their tolls on CFLs killing them a lot sooner; also, outside will be incandescents too for the aforementioned reason). But I have a whole year to stock up on 60 watt and 40 watt incandescent bulbs.

I think CFLs can cause headaches in some people whereas incandescents don't necessarily. That's what I've read.

I've used low-flow showerheads (1.5gpm) and higher-flow ones. Low-flow tends to take too much time to rinse shampoo and conditioner out of my hair. I'd prefer a dual-flow option so I can choose which I want, or perhaps dual showerheads (two things coming out of the wall) so I can swap between low- and high-flow showerheads.

But, I am ultimately replying to poster #42424307 because of this. Go look up the comparison between CFLs and LED bulbs. Right now, CFLs I think are the better economic option when you factor in the price. Although, if LEDs are durable (heat- and humidty-wise), and truly last 50k+ hours, once price comes down, maybe they'd be a feasible option for outside lighting.

Re:I am sick and tired... (2)

timeOday (582209) | about a year and a half ago | (#42424387)

The basic problem is there is no consensus on how to price the destruction of non-renewable resources, nor generalized damage to the environment. I would not expect a tidy solution to that issue, ever.

420 (0)

Anonymous Coward | about a year and a half ago | (#42424117)

oh what the weed farmers are going to do with this now... you should be able to replace a 600w high pressure sodium light with a 100w equivelant that performs real world better, and narrow it down to the ideal red and blue spectrum ranges for vegitative and flowering growth. if the cost is similar to current LED's it shouldnt cost more than 500$ per light and they would last for many years not a few months. the lower heat dissapation means easier growing and less worry about airflow, meaning co2 machines would maximize productivity. this is space age farming at its finest, and you wont need a princly budget to do it all. colorado and washington rejoice! and for everyone else, lower heat dissapation and lower electricity bills would make current identification methods that the DEA and police use obsolete. the savings in electricity mean quick ROI as well. i wish i had no morals sometimes lulz.

Re:420 (1)

Osgeld (1900440) | about a year and a half ago | (#42424139)

eh phosphorus does not emit the same radiation as a hps or metal halide... its not about color its about spectrum

Re:420 (2)

bmo (77928) | about a year and a half ago | (#42424195)

Color *is* spectrum.

HTH.

--
BMO

Re:420 (1)

Osgeld (1900440) | about a year and a half ago | (#42424223)

yea but a LED putting out damn near perfect X kelvin isnt going to give you the same effect as a wideband ball of fire in gas

you seem to misunderstand colour temperature (4, Informative)

Chirs (87576) | about a year and a half ago | (#42424287)

When someone talks about "X Kelvin" as a colour temperature, they mean the spectrum emitted by a black-body at that temperature, which by definition is full-spectrum.

To a first approximation the sun emits radiation at 5800K.

Re:420 (3, Interesting)

timeOday (582209) | about a year and a half ago | (#42424317)

No, but outputting a mixture of just 4 pure wavelengths works well [sandia.gov] in initial studies.

Re:420 (1)

WaffleMonster (969671) | about a year and a half ago | (#42424533)

Color *is* spectrum.

What your eyes think they see and what "spectrum" is actually emitted are separate items.

Re:420 (0)

Anonymous Coward | about a year and a half ago | (#42424297)

you should be able to replace a 600w high pressure sodium light with a 100w equivelant that performs real world better

You are underestimating the efficiency of high pressure sodium lights, modern HPS bulbs push ~135 lumens per watt, and almost all of it is in the right spectrum for absorption by plants. TFA's 200 lum/W leds seem to be only available in white, so once you filter out the unused spectrum, I'm not quite sure those would even by more efficient than the HPS.

Pot Farming (0)

Anonymous Coward | about a year and a half ago | (#42424135)

Just got a little cheaper and more covert.

light and color quality (2)

carnaby_fudge (2789633) | about a year and a half ago | (#42424141)

How do these compare to incandescent lights for color/temperature appearance and so forth. That's been the real deal breaker for me so far with other incandescent alternatives.

Re:light and color quality (3, Informative)

Osgeld (1900440) | about a year and a half ago | (#42424183)

its pretty common, if not standard issue now to put a patch of phosphorous over a UV led to generate the final visible light in these high powered LED's. so its very similar to what you can expect out of a CFL (course these things measure in cm)

you do get advantages though, the starting UV is generated by a crystal and not an electric arch in a vacuum so its more "rich" and if its not half assed you dont get flicker

Re:light and color quality (2)

girlintraining (1395911) | about a year and a half ago | (#42424271)

its pretty common, if not standard issue now to put a patch of phosphorous over a UV led to generate the final visible light in these high powered LED's. so its very similar to what you can expect out of a CFL (course these things measure in cm)

And we can of course trust that the manufacturing quality is 100% on these -- that the UV light isn't leaking out. There are health problems with certain wavelengths. However, I'm sure there's nothing to worry about...

Re:light and color quality (1)

Anonymous Coward | about a year and a half ago | (#42424327)

And we can of course trust that the manufacturing quality is 100% on these -- that the UV light isn't leaking out. There are health problems with certain wavelengths. However, I'm sure there's nothing to worry about...

Oh, spare us your scaremongering. This is exactly how fluorescent tubes work.

Re:light and color quality (1)

rubycodez (864176) | about a year and a half ago | (#42424371)

Do some research, there is high correlation between flourescent light exposure and many diseases by credible scientists

Re:light and color quality (1)

dr2chase (653338) | about a year and a half ago | (#42424467)

You could go look at the data sheet, and see that these LEDs don't emit any wavelengths shorter than about 410nm, and the primary color appears to be "royal blue" (445nm).

No need to be "concerned".

Re:light and color quality (2)

Osgeld (1900440) | about a year and a half ago | (#42424537)

I work with LED lighting every single day, and in one instance we had an issue where a soft dome got knocked off, the spectrum is actually so near blue it looks blue, its probably safer than a blacklight you used for your posters in college

Candlepower Forums... (5, Informative)

Anonymous Coward | about a year and a half ago | (#42424169)

...seems to have the expert analysis. Some people are into flashlights so much and the LEDs that may be used in them, it's crazy what details they keep tabs on.

Post on the Cree MK-R LED at Candlepower Forums. [candlepowerforums.com]

Crappy or Cree, that is the question for importers (2)

D4C5CE (578304) | about a year and a half ago | (#42424311)

flashlights ... and the LEDs that may be used in them, it's crazy what details they keep tabs on

They have to, since these things are typically ordered from overseas, with prohibitive return postage fees, and many times some manufacturer or vendor will try to become the cheapest by changing to LEDs of a crappy (i.e. fake) rather than Cree variety. When the item arrives, one usually has just a few days to ascertain whether it is genuine or if a refund needs to be requested from the payment service.

Re:Candlepower Forums... (1)

Charliemopps (1157495) | about a year and a half ago | (#42424459)

Wow... a forum about lightbulbs. The true power of the internet is it lets people with similar interests, even if their interests are totally insane, get together. It never ceases to amaze me.

jaffa... (3, Funny)

Anonymous Coward | about a year and a half ago | (#42424203)

jaffa cree!

Re:jaffa... (0)

Anonymous Coward | about a year and a half ago | (#42424237)

jaffa cree!

That's what the snake heads always say before they light your ass up.

Re:jaffa... (0)

Anonymous Coward | about a year and a half ago | (#42424245)

Where is the sho'va teal'c!? Tell me and you may yet live to serve as my hok'tar!

Re:jaffa... (0)

Anonymous Coward | about a year and a half ago | (#42424319)

It's actually Kree. [wikia.com]

Re:jaffa... (0)

Anonymous Coward | about a year and a half ago | (#42424329)

details...details..

Re:jaffa... (0)

Anonymous Coward | about a year and a half ago | (#42424337)

Actually it's "kree", just don't ask me what it means.

Energy efficiency (1)

girlintraining (1395911) | about a year and a half ago | (#42424255)

For comparative purposes, an incandescent bulb puts out about 52 lumens per watt. This LED is therefore about four times more efficient at converting electricity into light than the traditional lightbulb. That said, one of the big problems with LED lighting is that the light tends towards the blue end of the spectrum, whereas incandescents tend towards the red. Studies have shown that it is blue light that suppresses melatonin production, which in turn upsets the sleep/wake cycle. Similar problems have been found with LCD monitors compared to CRT monitors.

We may be improving energy efficiency, but we're actually creating health hazards in doing so -- because people assume all light is equal. It isn't.

Re:Energy efficiency (2)

Mike_EE_U_of_I (1493783) | about a year and a half ago | (#42424285)

For comparative purposes, an incandescent bulb puts out about 52 lumens per watt.

That's the theoretical maximum, that no bulb actually gets near. For example, a typical 60 watt bulb will give you 15 lumens per watt.

http://www.efi.org/factoids/lumens.html [efi.org]

Re:Energy efficiency (5, Informative)

timeOday (582209) | about a year and a half ago | (#42424295)

an incandescent bulb puts out about 52 lumens per watt.

If only! "An upper limit for incandescent lamp luminous efficacy (LER) is around 52 lumens per watt, the theoretical value emitted by tungsten at its melting point" (wikipedia). In fact a 40W tungsten bulb outputs 12.6 lumens/watt, up to 17.5 for a 100W bulb. Incandescent bulbs aren't even in the ballpark anymore.

As to whether some people assume all light is equal, I suppose some do. But others take it very seriously [sandia.gov] . It is not an overlooked issue.

Re:Energy efficiency (0)

Anonymous Coward | about a year and a half ago | (#42424361)

That said, one of the big problems with LED lighting is that the light tends towards the blue end of the spectrum, whereas incandescents tend towards the red. Studies have shown that it is blue light that suppresses melatonin production, which in turn upsets the sleep/wake cycle.

The studies I've read that involve what you are referring to only applied to blue lights being on when a person is sleeping.

I never had to worry about that even with the plethora of blue LED devices ranging from my mouse, keyboard, stereo, laptop, and whatnot because any amount of light disturbs my sleep, and I cut pieces of electrical tape to cover all light sources that have no control other than removing power.

Re:Energy efficiency (2)

WaffleMonster (969671) | about a year and a half ago | (#42424565)

The studies I've read that involve what you are referring to only applied to blue lights being on when a person is sleeping.

Just because you think white leds look white does not mean they don't have a nasty blue spike in their output spectrum. What you can't see can still hurt you.

Re:Energy efficiency (1)

Osgeld (1900440) | about a year and a half ago | (#42424575)

you can take the exact same die, slap a different phosphorous on it and make it orange, red, green whatever

and just FYI CRT monitors use the exact same theory, there is no light bulb, its a electron beam exciting a patch of phosphorus. CRTs can produce the exact same color temperatures as any other monitor

so please, continue with your ignorant health FUD

Theoretical Maimum (1)

MyLongNickName (822545) | about a year and a half ago | (#42424275)

Is there a theoretical maximum lumens / watt ratio? My 30 second search on Google does't show any relationship between the two terms, but I have to imagine there is some type of maximum...

Re:Theoretical Maimum (3, Informative)

MyLongNickName (822545) | about a year and a half ago | (#42424291)

A 90 second search revealed the following "A common choice is to choose units such that the maximum possible efficacy, 683 lm/W, corresponds to an efficiency of 100%"

http://en.wikipedia.org/wiki/Luminous_efficacy [wikipedia.org]

Re:Theoretical Maimum (5, Informative)

queazocotal (915608) | about a year and a half ago | (#42424373)

It's way, way, way more complex than this.

683lm/W is the maximum luminous efficacy for light, yes, but that's green light.

To reproduce in full the solar spectrum so that it is indistinguishable from white light requires you to produce a 'white' that produces light from about 400-700nm (UV to IR borders).
If you take into account flourescence and its effect on colour, perhaps 350nm is the top end.
This would take perhaps 180lm/W.

As you move from near-solar (or tungsten) identical bulbs to more limited 'whites' - you get about 250-400lm/W being the maximum.
This varies from pretty good white that you won't notice being different from actual white to something rather more limited, with just blue at 430nm or so, and greenish yellow at 560nm.
This will to a cursory glance look right, but will have truly wretched colour reproduction.

Re:Theoretical Maimum (0)

Anonymous Coward | about a year and a half ago | (#42424627)

Yeah, but 90 seconds was already 100x more than the average person is willing to spend researching something on the internet, and your post was so long I couldn't get past the second sentence. Just give me the 86 millisecond half-sentence version next time. And don't tell me anything wretched, eh?

luminous efficacy (4, Informative)

terec (2797475) | about a year and a half ago | (#42424321)

Wikipedia has a list of luminous efficacies:

http://en.wikipedia.org/wiki/Luminous_efficacy [wikipedia.org]

200 lm/W seems pretty good; the theoretical limit is around 300 lm/W for LEDs, and that's about 44% overall efficiency.

Poor Spectrum (5, Insightful)

Anonymous Coward | about a year and a half ago | (#42424357)

While I *do* love to hear stories like this, and I believe that LED lighting, in some form, is the future, it dissappoints me to see that so-called "white" LEDs still produce quite poor spectra. Check out the spectrum on page 4 of the datasheet given on the MK-R series page. Compare this to the sun's spectrum. Because these are phosphor-based LEDs, you get a relatively narrow blue-violet peak (the true colour of the LED), followed by a wider hump, peaking at about yellow (the broad emission spectrum of the phosphor coating, which is down-converting those blue photons). While this looks "pure white" when you look directly at the beam, it renders colours very poorly (i.e. the reflected light from objects looks the wrong colour). This is what causes LEDs and fluorescent lights to often make a room appear sickly and food look unappetizing. Ideally, we should strive for a light which closely emulates the sun's spectrum, but this is obviously challenging.

Fortunately, there are a few next-gen LED technologies on the horizon. Quantum dot-based LEDs seem promising. By making dots of a specific size, you can precisely tune the output wavelength of a QD LED. Presumably you can combine a whole bunch of QD LEDs, each tuned to a different wavelength, to approximate the sun's spectrum. Alternatively, certain types of organic LEDs offer the ability to tune the wavelength, and similarly, produce a composite device which has a more ideal spectrum.

Still, until these materialise, plain 'ol incandescents are the only cheap light sources which produce a nice, continuous blackbody spectrum. Sigh.

Re:Poor Spectrum (1)

dr2chase (653338) | about a year and a half ago | (#42424507)

In reply to a previous Slashdot article on LEDs, this minor effort: http://dr2chase.wordpress.com/2011/02/26/led-color-rendering/ [wordpress.com]
The summary is, if you take decent LEDs (CREE or Luxeon) and mix the color temperatures (warm/neutral/cool) it's not bad. Your eyes adapt; the camera is much less forgiving.

And decent LED kicks the crap out of fluorescent.

Re:Poor Spectrum (2, Insightful)

Anonymous Coward | about a year and a half ago | (#42424673)

I'm not sure how combining the warm, neutral and cool LEDs would accomplish much. If you look at the relative spectral power distribution [cree.com] 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".

Power output level (1)

Anonymous Coward | about a year and a half ago | (#42424429)

If you read the datasheet, you'll see that the CREE MK-R is rated for a maximum of 15W, but the measurement of 200 Lumen/W is done at 1W output. It is known that LED's efficacy drops off quickly as the output power increases.

In the past, CREE have released similar news, claiming certain lumen per watt LED is available, all of them are measured at 1W output, but none of them have a power rating as high as 15W. I think comparing the efficacy of these chips @ 1W while they have completely different power rating is actually kind of misleading.

How bout the stock price (1)

Anonymous Coward | about a year and a half ago | (#42424463)

Couple years ago I invested in Cree cuz of their LED lights, lost about 15% in a couple months before I could get out. Now they're at about 1/3 of what they were when I got out.

don't care (0)

Anonymous Coward | about a year and a half ago | (#42424499)

until they show up in walmart they're just yet another super efficient thing we don't have unless you hunt the fuckers down.

And even then. these like everything else will be shit out in china and have crap quality.

Less heat! (0)

Anonymous Coward | about a year and a half ago | (#42424551)

With this power savings in LED tech humans can grow plants on the moon. Not to mention less heat will make it so to national guard doesn't contact the local authority about my hot closet.

comparison (1)

slashmydots (2189826) | about a year and a half ago | (#42424697)

Those mega bright HID headlights usually come in around 3000 lumens at 35 watts. So an LED that bright is pretty insane.
Load More Comments
Slashdot Account

Need an Account?

Forgot your password?

Don't worry, we never post anything without your permission.

Submission Text Formatting Tips

We support a small subset of HTML, namely these tags:

  • b
  • i
  • p
  • br
  • a
  • ol
  • ul
  • li
  • dl
  • dt
  • dd
  • em
  • strong
  • tt
  • blockquote
  • div
  • quote
  • ecode

"ecode" can be used for code snippets, for example:

<ecode>    while(1) { do_something(); } </ecode>
Create a Slashdot Account

Loading...