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13 September 2007


Cree reports record efficacy for power LEDs

Cree Inc of Durham, NC, USA has reported record luminous efficacies for packaged, high-power LEDs operating at a drive current of 350mA in R&D.

The efficacies are 129 lumens per watt for a cool-white LED (with a correlated color temperature of 5813K) with a light output of 135.7 lumens, and 99 lumens per watt for a warm-white (2950K) LED with an output of 104.2 lumens, as measured by the US National Institute of Standards and Technology (NIST) after five minutes of operation (in order to ensure thermal stabilization).

Higher efficiencies have been reported previously in R&D, for example 150lm/W last December by Japan’s Nichia, but only from small-area LED chips yielding low output due to a drive current of just 20mA.

The chips used in Cree’s latest LEDs are reportedly the same as used in the cool-white LED driven at 4A to demonstrate output of 1050 lumens from a single-die R&D device (albeit with efficacy of just 72lm/W) .

Cree reckons that, in coming years, its investments in such core LED technology could lead to products that replace traditional light sources in all commercial applications. The technology advances may be seen in commercial products within 12-24 months, the firm adds.

“To replace traditional light sources, LEDs need to provide both high light output and high efficacy,” says John Edmond, co-founder and director of advanced optoelectronics.”

See related item:

Cree achieves 1000 lumens from single-die LED

Philips Lumileds claims white LED record of 115lm/Watt at 350mA

Nichia develops record 150lm/W white LED

Seoul Semiconductor claims record with 100 lm/W @ 350 mA P4 LED

Nichia reports white LEDs producing 138lm/W at 20mA; over 90lm/W at 350mA