Cree's New Blue XLamp XR-E LEDs are 70-Percent Brighter

[gtsx]

http://biz.yahoo.com/pz/070620/121646.html

http://www.primenewswire.com/newsroom/prs/?pkgid=3852

Wednesday June 20, 9:00 am ET

DURHAM, N.C., June 20, 2007 (PRIME NEWSWIRE) -- Cree, Inc. (NasdaqGS:CREE - News), a market leader in LED solid-state lighting components, today announced commercial release of blue XLamp(r) XR-E LEDs that are 70-percent brighter than the company's previous blue power LEDs. The new blue XR-E produces maximum luminous flux of 42 lumens at 350 mA.
A photo accompanying this release is available at http://www.primenewswire.com/newsroom/prs/?pkgid=3852
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``The release of our award-winning XR-E LED in blue is the next step in our mission to be the first LED supplier to offer a full color range of lighting-class LEDs,'' stated Norbert Hiller, Cree vice president and general manager for lighting LEDs. ``The new blue XR-E LEDs offer lighting designers increased flexibility for their designs. They can now choose to use fewer LEDs to lower the overall design cost, or use the same number of LEDs to achieve greater light output.''
The blue XR-E is the newest release in the award-winning XLamp XR-E family, which includes industry-leading performance in warm- and cool-white LEDs. All are available in production quantities. Additional information about XLamp LEDs can be obtained by calling XLamp Sales at 919-313-5300 or at http://www.cree.com/xlamp.
About Cree, Inc.
http://www.cree.com.

 

[jtr1962]

Assuming a luminous efficacy for the emitted spectrum of around 62 lm/W (about right for a center wavelength of 470 nm), and a Vf of 3.4V at 350 mA, these are about 57% efficient. Now if only green and red emitters can reach these levels we could have a RGB white light source with an efficiency in the 200 lm/W area. Impressive, especially from a heat management standpoint (only 43% of the power put into these comes out as heat).

 

[2xTrinity]

Assuming a luminous efficacy for the emitted spectrum of around 62 lm/W (about right for a center wavelength of 470 nm), and a Vf of 3.4V at 350 mA, these are about 57% efficient. Now if only green and red emitters can reach these levels we could have a RGB white light source with an efficiency in the 200 lm/W area. Impressive, especially from a heat management standpoint (only 43% of the power put into these comes out as heat).

I think some of the red LEDs out there are likewise extremely efficient -- the Luxeon IIIs for example emit something along the lines of 50% more lumens than the greens at the same input power, even though 530nm green has 4 times the efficacy of 630nm red. That suggests about 30% efficiency.

While that's not quite as efficient as the blue, it's apparent the green, at an estimated 5% efficiency, is the weak link. At this point, it seems like a better way to get green would be using a blue emitter with a green phosphor that converts all the blue light (rather than just a portion, like the white LEDs). A filter might even be used to remove any excess blue, and I'm certain that would still be more efficient than the direct green emitters.

If they had a 56% efficient green emitter though, and got red/orange efficiency to match, it would be possible to exceed 200 lumens per watt, especially for a warmer color temperature (since blue contributes the least to lumens, the warmer the color temp, the higher the output/watt)