PHOTONIC FRONTIERS: WHITE-LIGHT LEDS - White-light LEDs promise a bright future for solid-state illumination

摘要

Light-emitting diodes promise a future of high-efficiency, low-cost lamps for general illumination, but challenges remain in cranking up performance and bringing down costs. White-light emitting diodes (LEDs) already are standard in products from pocket flashlights to solar-powered night lights on suburban lawns. The office of Energy Efficiency and Renewable Energy at the US Department of Energy (DoE) heralds white-light LEDs as the "great white hope" for general illumination because they promise to bring down power consumption by improving efficiency well beyond today's fluorescent lamps. Progress is evident in steady improvements in efficiency measured in lumens output per watt of input power, and in the appearance of the first household solid-state lightingin stores. Yet formidable obstacles remain before solid-state lighting becomes the norm for homes and businesses. Costs need to come down so white-light LEDs make economic sense. Color balance needs to be improved for many applications. And tough technical challenges remain, particularly in reducing the decline in efficiency that now comes with higher drive currents.