December 7, 2009
They already light up Christmas trees, traffic signals, crosswalks and vehicle brakes. And they may someday completely displace incandescent lighting from the marketplace. This is because light-emitting diodes (LEDs) are at least four times more energy efficient than standard incandescent bulbs and about 25-50 times longer-lasting; other solid state lighting, such as flat panel organic LEDs (OLEDs) are not far behind.