The Light Source LED

E v o l u t i o n o f L i g h t

Efficient Light Sources

LEDs are extremely efficient light sources. In 2008, the luminous efficiency of white LEDs had already achieved values of over 100 lumens/watt (lm/W. Light emitting diodes will soon be available with a luminous efficiency of up to 140 lm/W. That means that LED devices will achieve the luminious efficiency values of flourescent lamps.

Future generations of LEDs used widely in interior illumination will contribute to reduced energy consumption and costs, as well as reduced environmental impact. The same applies to exterior lighting, either for stationary applications with long-life, energy saving LEDs (potentially coupled with solar cells) being applied as trail markers or for mobile use.

The Light Flux

The light flux values for currently available LEDs amounts to between several lumens (lm) for low-power LEDs (approx. 50 to 100mW of applied power) and up to 1000 lm for high-performance LEDs (up to 15 W). A more useful indicator for users are the light flux packages that can be achieved with LED modules.

Life expectancy depends on temperature

The light expectancy of LEDs dependings on the temperatures at which they are run and in which they are located. At room temperatures, LEDs -- and hence LED modules -- offer very long life expectancies of up to 50,000 hours of operation.

Unlike light bulbs, where a break in the filament spells the end of the service life, total failures in LEDs are extremely rare. The light intensity instead begins to decrease very gradually. This characteristic is known as degradation. The time frame during which the original light flux degrades to 50 percent of the original intensity is what defines an LEDs life expectancy.

More information of note about LED technology:

German:
http://de.wikipedia.org/wiki/Leuchtdiode

English:
http://en.wikipedia.org/wiki/LED