LED Lights - Key Challenges Facing The Technology

What are light-emitting diodes (LEDs)?
An LED is a very small (dot-sized) electrical device that produces light through the semi-conducting properties of its metal alloys. LEDs have been around since the 1960s, but were used mainly as simple indicator lamps in electronics and equipment. White LEDs are now approaching performance levels that make them attractive for use in automobiles, aircraft, elevators, and some task light applications.

What is solid-state lighting?
Solid-state lighting (SSL) uses semi-conducting materials to convert electricity into light. It is the first truly new lighting technology to emerge for many years. SSL is an umbrella term encompassing different types of technologies including light-emitting diodes (LEDs) and organic light-emitting diodes (OLEDs). While both technologies are evolving rapidly, LEDs are the more mature technology, particularly for white-light general illumination applications.

Are LEDs available for general lighting?
A variety of white LED products are available on the market including desk and under-cabinet lights, flashlights, head lamps, outdoor pathway lights, and decorative string lights. For most illumination applications, however, white LEDs cannot yet compete with traditional light sources on the basis of performance or cost. Colored LEDs are often cost-effective and offer energy efficiency and durability for traffic signals, exit signs, commercial signage, and other indicator applications.

Are white LEDs energy-efficient?
The best white LEDs are similar in efficiency to CFLs, but most of the white LEDs currently available in consumer products are only marginally more efficient than incandescent lamps. Lumens per watt (lpw) is the measure of how efficiently the light source is converting electricity into usable light. The best white LEDs available today can produce about 45-50 lpw. For comparison, incandescent lamps typically produce 12-15 lpw; CFLs produce at least 50 lpw. Many LED products use only a small amount of energy, and therefore may appear energy efficient, but they often have very low light output. True energy efficiency means using the most efficient light source or system that is capable of providing the amount and quality of light needed. On-going research and development efforts are making steady progress in improving the performance of white LEDs to levels suitable for general lighting applications.

Source: EERE

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