While other companies have announced results above the 100 lm/W threshold, these have all related to small devices driven at 20 mA. For example, Nichia recently announced a 150 lm/W lamp-type white LED demonstration (see news item). The Lumileds announcement shows that developments in the power LED segment are keeping pace with standard LEDs.
The white LEDs developed by Lumileds' Advanced Labs are built around 1x1 mm2 chips. The devices delivered 136 lm when driven with a current of 350 mA, corresponding to an efficacy of 115 lm/W. Lumileds emphasizes the correlated color temperature (CCT) of 4685K, which is significantly lower than values typically reported.
Equally impressively, at 2000 mA the white LEDs delivered 502 lm, corresponding to an efficacy of 61 lm/W. Lumileds says that it achieved these record results for white LEDs by combining several new and innovative technologies, including breakthroughs in epitaxy, device physics, phosphors, and packaging technologies.
Steve Landau, Lumileds' worldwide marcom manager, says that it will be a while before LEDs with this type of performance are available in the market. "However, it is clear that we have demonstrated a set of innovations that will enable performance to be significantly increased in the not too distant future," says Landau.
"We will be releasing new products this quarter that will begin incorporating one or more of the technologies that went into the devices with the record performance."
The light output performance announced by Philips Lumileds is 17 times greater at the same power than was available in 1999 when the company introduced the first high-power LED. While performance numbers continue to increase for low power LEDs, operating at lower currents such as 20mA, high-power LEDs are required to deliver the quality and quantity of light required for today’s and tomorrow’s lighting applications.
