Cree Introduces 200 Lumen/Watt Production Power LEDs 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.'"
Re:Slashvertisment (Score:5, Insightful)
Poor Spectrum (Score:5, Insightful)
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:Cooling is the issue (Score:5, Insightful)
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:Poor Spectrum (Score:2, Insightful)
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".
Re:These Cree guys are really bright. (Score:4, Insightful)
Price?
Re:Cooling is the issue (Score:3, Insightful)
One issue with bicycle lights, especially those popular in North America, is that their reflectors are awful. They spray light everywhere. That's only really useful when mountain biking; when cycling on the road, light sprayed into the air is wasted light, and more powerful lights create a hazard for other cyclists and motorists. A good amount of engineering goes into a proper reflector, like those used on car headlights. There are some bike lights that do it right (Phillips has some), but the ones these LEDs are going to be thrown in first are going to be of the junk variety.
Re:Cooling is the issue (Score:5, Insightful)
CFL's rarely last more than 10 months. If they do they are at half the brightness of a ten year old bulb.
Let me guess: You also pay $6 for eight of them...
Re:I hope these don't end up as car lighting (Score:2, Insightful)
Not true, at all.
By placing them into smaller housings, they are using lenses to spread the bright LED or HID light.
Also, using directed beams and lenses (aka projectors) they can direct the light where it should be, THE ROAD, and not your eyes. Since the lumen output of light is only capable of lighting a certain distance anyway, properly adjusting the headlights is important too.
Don't hate the player (LED/HID lights) hate the game (the dickheads who don't adjust their headlights.)