Seoul's single-die source packs 240 lumen punch
Seoul Semiconductor says that its latest LED technology has resulted in a single-die white source that can emit up to 100 lumens per Watt. Importantly, Seoul is claiming the high efficacy figure for chips that operate at the 350 mA drive current that is required for general illumination applications.
The new "P4" emitter is claimed to produce 240 lumens at its maximum drive current. Two types of commercial device are available "“ one operates at a typical efficacy of 100 lm/W at 350 mA, and the other is rated at 80 lm/W.
"Conventional LEDs have been known to emit more than 100 lumens with several dies," said Seoul Semiconductor CEO Jung Hoon Lee. "The P4 is the only LED product in the world with 240 lumens via a single die."
Seoul says that the high luminosity was reached through its proprietary phosphor and packaging techniques, and it would appear that further improvements are in the pipeline:
According to the company's statement, we can look forward to seeing a 135 lm/W source next year, and more incremental improvements are expected to lead to 145 lm/W performance early in 2008.
To put the lm/W figure in context, a typical fluorescent lamp operates at 70 lm/W, while traditional incandescent bulbs deliver 15 lm/W.
In October this year, Cree revealed its brightest commercial product - a 160 lm white LED XLamp, which is said to operate with 85 lm/W efficacy at 350 mA drive current.
Meanwhile, researchers at Nichia's laboratories recently published a paper in the Japanese Journal of Applied Physics detailing a high-power white LED capable of producing 402 lumens at 2 A, and a luminous efficacy of just over 90 lm/W at 350 mA.