LED Technology — Definition

Definition

A light-emitting diode produces light through electronic processes in a suitable semiconductor. An LED lamp combines emitters with electrical, thermal and optical components, so source performance differs from complete luminaire performance.

Watts measure electrical power, lumens measure luminous flux and lux measures illuminance on a surface. Luminous efficacy is expressed in lumens per watt. The 2014 Nobel Prize in Physics recognised efficient blue-LED work by Isamu Akasaki, Hiroshi Amano and Shuji Nakamura, important for practical white lighting.

Useful lighting must be assessed through the required illumination, colour quality, operating conditions and total electricity use.