LED is popular for "Light Emitting Diode" a semiconductor that emits light in colours: monochromatic blue, green, yellow, red and other shades are available, even white light can be made using blue LED and covering the die with phosphor.

Since its inception in 1962 continued development has increased available colour ranges and illumination efficiency. High efficiency white diodes have been available since 1993 and within the next 10 years the efficiency of LED’s is expected to improve to 300 lm/W, making LED's the most efficient light source known.

Advantages of LED’s besides high efficiency is low temperature, low energy consumption and long lamp life. Pulsed operation and precise light design is possible through the defined light distribution and small size.