LED (Light Emitting Diode), a solid state semiconductor device made out of Silicon element which converts electrical energy into light energy, is increasingly becoming popular worldwide in view of its wide-ranging benefits in the fields of lighting, and other fields of energy.
LED-based lighting systems are very durable as there are no mechanical or moving parts. LED's consume low power, which leads to energy savings. The common incandescent lamps have a life span of 1,000 – 5,000 hours, while LED lamps have a life of 50,000 hours with continuous usage. The longer life of LED-based lamps reduces the frequency of replacements, thus leading to significant financial savings as well as improving the environment, in particular with respect to maintenance and recycling. Although the initial investment for installing the LED-based systems is higher, the investment cost can be recovered in a short period and, therefore, they are economic in the long run.
LED lighting systems produce greater brightness, with constant increase, and have higher lumen output than the traditional lighting systems.
LED products do not produce heat in the form of infra red radiation, unlike incandescent lamps and other conventional light sources, which produce massive amount of heat, making the environment unpleasant. The absence of heat production enables installation of more equipment or fixtures in various industries such as textile mills and steel plants.
LED is cold generation of light which leads to higher efficiency because most of the energy is radiated within the visible spectrum. Common energy efficiency light sources such as fluorescent lamps, incandescent lamps produce high thermal radiation outside the visible spectrum.
LED basically consist of two elements of processed material: P-type semiconductors and N-type semiconductors. These two elements are placed in direct contact for the formation of a region called PN junction. The composition of the different material determines the wavelength and color of the light generated.
LED has a transparent package which allows visible or infra red energy to pass through.
In order to get different colors of LED the main semi conductor materials used for manufacturing are:
– Indium Gallium Nitride (InGaN) which will produce Blue, Green and Ultra violet high brightness LED's
– Aluminum Gallium Indium Phosphide (AlGaInP) to produce Yellow, Orange and high red brightness LED's.
– Aluminum Gallium Arsenide (AlGaAs) that will produce Red and Infra Red LED's.
Gallium Phosphide (GaP) to produce Yellow and Green LED's.
LED systems can be switched on instantly even under cold temperature and this helps in making environment in the industrial area more pleasant.
