The researchers at Purdue University are just full of bright ideas these days, and this weekend was no exception. Thanks to a major breakthrough, they may have overcome a major obstacle for "solid state lighting," which laymen like to call LED (light emitting diode). That obstacle? Cost. LEDs are expensive, mostly because their innards are created on a substrate of sapphire. That means only a few gadgets and luxury cars headlights have benefited from the tech so far. Purdue researchers solved the conundrum with a technique that creates the LEDs on low-cost, metal-coated silicon wafers. This is great news for energy conservation, because while LEDs are much more efficient than their incandescent brethren, they are also 20 times more expensive to produce. [Purdue University]