LED Light Knowledge-What consumers should know about Solid State Lighting

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LED Light Knowledge-What consumers should know about Solid State Lighting for general lighting applications?

An introduction to Solid State Lighting
Solid-state lighting (SSL) is the new lighting technology to emerge for many years: it uses semi-conducting materials to convert electricity into light. The term “solid state” refers to the fact that light in an LED is emitted from a solid object (a block of semiconductor) rather than from a vacuum or gas tube, as is the case in traditional incandescent light bulbs and fluorescent lamps. SSL covers different types of technologies including light-emitting diodes (LEDs) and organic light-emitting diodes (OLEDs). LEDs are the more mature technology compared to OLEDs, particularly for white-light general illumination applications, but both technologies are evolving rapidly.
White LEDs for general illumination

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LED lifetime depends greatly on operating temperature. An increase in operating temperature of 10 °C can cut the useful life of an LED in half. So to evaluating LED product life claims, one should ask about the assumed operating temperature and any measures to mitigate heat in the device.
White LEDs cost

For the moment, white LEDs cost significantly more than traditional light sources. The combination of high price and low light output may make them a poor replacement for current technology in most general illumination applications. For comparison, today’s white LEDs cost more than $50 per thousand lumens, a typical 75-watt incandescent light bulb, costs about $1.00 per thousand lumens and a comparable CFL costs less than $5.00. The technology targets to achieve are $20/klm by 2007, less than $5/klm by 2012, and less than $2/klm by 2020. However, for some applications, the extra durability of LEDs is worth a higher purchase price. Outdoor pathway and step lighting is an example of a sensible application for today’s white LEDs. They provide a small amount of light right where it’s needed, avoid frequent bulb changes in fixtures that are difficult to access, and can be powered by solar cells, eliminating the need for running wire outdoors. LEDs are also good for applications where vibration often leads to early failure of conventional light sources. Being a solid-state device, LEDs are highly resistant to damage caused by vibration.