Light emitting diodes (LED's)

You may be familiar with seeing LED's as tiny indicator lamps on electronic equipment. In recent years LED's have become more powerful and more multicoloured. They have almost reached a lumen output level that makes it possible to achieve useful output for use in luminaires. The main characteristics of LED's are:

	Very long life (30 years in typical application).
	LED's do not produce light by heating a filament, or by producing an arc. Therefore they generate virtually no heat (compared to an incandescent lamp which wastes 50% of the applied energy as heat).
	Zero Ultra Violet light generated.
	Available to emit Red, Green, Blue, Orange and White light.
	Colour mixing possible for luminaires with Red, Green & Blue LED arrays.
	Efficiency compatible with GLS & dichroic lamps (up to 12 lumens per Watt).
	Very small size enables many LED's be built into an array for increased output.
	Vibration resistant. With no filament to shake loose, LED's will withstand enormous amounts of vibration.
	Easily dimmed by reducing current (DC or pulse width modulation).
	Narrow beam angles are possible without use of a reflector.

White LED's operate differently to the other colours. A white LED has a blue LED semiconductor source that illuminates a phosphor to produce white light. A white LED will not last as long as the other colour because of the gradual depreciation of the phosphor powder. The lumen output may decline to 50% of the initial value after 6000 hours of operation.

Applications
Replacement for dichroic luminaires in areas where low temperature operation is important. For example pavement mounted up-lights that will not cause public liability problems.

Situations where access is difficult. Take advantage of the super long operational life of LED's in situations where replacement of a luminaire would be costly.

Colour changing applications for disco or bar environment. The control of colour can be programmed into the combined power supply / controller. The controller can accept input from an audio source to pulse the LED's along with the beat.

Garden lighting. All of the advantages of LED's can be applied to garden lighting. The extremely low heat generated will not raise the temperature of the luminaire, thus ensuring its watertight seals remain intact for many years.

Ice skating rink. LED luminaires have been used beneath the ice to give a multi colour effect to the ice without any problems with ice melting from luminaire heat.