LED Lighting

Abstract

Light-emitting diodes (LEDs) are a semiconductor technology whose application to general-purpose lighting is rapidly growing, with significant potential for energy savings. LED devices perform exceptionally well in lab conditions, proving up to 10 times more efficient than incandescent lights. These impressive laboratory results can be diminished in actual use in a lighting fixture because of remaining technical and design challenges. However, LED lighting products are now available that are three to four times more energy efficient than incandescent bulbs and last up to five times longer than compact fluorescents, so far the longest-lasting lighting alternative. Several large, well established firms in the traditional lighting industry have been working to resolve performance issues related to lamp and fixture design. Yet to be resolved is the cost issue; while LED or " solid state " lighting is rapidly dropping in price, it remains several times more expensive than traditional lights. The market for general-purpose LED lighting is currently very small, but it is growing rapidly as the technology improves and costs go down. In 2007 the global LED market was 4.6billion,andthegenerallightingportionrepresentedonlyanestimated74.6 billion, and the general lighting portion represented only an estimated 7% of these sales, behind LEDs for mobile appliances (44%), signs and displays (17%), and automotive uses (15%). Within the global lighting market, estimated at an annual 40-100billion—roughlyone−thirdofwhichconsistsoflightbulbs—LED−basedlightingrepresentsanevensmallerportion:anestimated.01100 billion—roughly one-third of which consists of light bulbs—LED-based lighting represents an even smaller portion: an estimated .01%. Still, sales of LED-based lighting products have grown 40–60% annually in recent years, and they are expected to reach 1.6 billion by 2012.