Why is everyone talking about LEDs?
The main reason is that they are the first really new light source in twenty years.
Although LEDs were first commercially manufactured in the 1960s, it is only in the past 15 years that they have been used in commercial lighting applications.
Before then, they were mainly used on indicator boards and signalling. Recently, high power LEDs have been developed, 1W and above, which means that they can produce useful quantities of light. LEDs are now found in every area of lighting application.
Their advantage over conventional light sources is their long life, efficiency and small size. Being solid state electronic devices, they are also very suited to mass production techniques. Solid State Lighting, SSL, is another aspect of the spread of high volume, modern technology electronic products such as mobile phones, personal computers and TVs.
The interest in LEDs comes with the speed of product development. The LED chip manufacturers produce greater and greater efficiencies year on year. Think how the power of PCs has developed. Early LEDs were hardly more efficient than Tungsten Halogen, whereas the latest chips are almost as efficient as high pressure sodium and yet produce white light.
Other advantages of LEDs are:
• Like other solid state devices, they can very easily be controlled digitally. Hence dimming and colour mixing can be programmed and integrated simply with other devices and services from a PC, building management systems or over the internet. They can be switched on and off instantly.
• LEDs do generate heat, but the actual beam of light from a luminaire is cool. There is no UV or IR in the beam; so LEDs can be used to light materials which are sensitive to heat and daylight. Do remember that the actual fitting will become warm or even hot, depending on its wattage.
• They can withstand impact and vibration better than conventional sources because there are no filaments or support wires to fail. Consequently, they are suited to
• The cooler they are, the more efficient they become and their life is extended.
• They are mercury-free and safe for the environment.
• Their small size and low heat output means they are suitable for confined spaces and shallow ceilings.