This a VERY interesting piece!
LED lighting can be great—but LEDs won't make a replacement for screw-in light bulbs any time soon.
By Ron Wilson, Executive Editor -- EDN, 5/8/2009
A wide-ranging panel discussion at EDN's Designing with LEDs seminar last week explored many of the issues LEDs will face as they move into commercial and residential lighting applications. There is great promise, the panelists insisted, but the path won't be easy. Francis Nguyen, senior product marketing manager at OSRAM, Willem Sillevis-Smitt, director of strategic marketing at Philips Lumileds, and Paul Scheidt, product manager at Cree Components, discussed the issues.
Conference chair and EDN editor Margery Conner opened the discussion with a simple question—why can't we just use banks of ordinary 5mm industrial white LEDs for lighting?
The answer turned out to be less than simple. For one thing, Scheidt said, a typical 5mm LED produces about 6 lumens. So a big commercial fixture would require thousands of LEDs, creating interesting problems for driver designers, and in the end consuming about the same power as a florescent fixture of the same output. "The big advantage for LEDs in lighting applications comes when you design the LEDs for that purpose," Scheidt said. "Then you can achieve output efficiency, directability of the beam, and reliability that you can't get any other way."
more at http://www.edn.com/article/CA6657192.html?spacedesc=features (http://www.edn.com/article/CA6657192.html?spacedesc=features)