An Introduction to the Fabrication of White Lightemitting Diodes

Light-emitting diodes, especially white light-emitting diodes are very attractive and fascinating lighting sources at this present time because they have the potential for high energy saving and environmental friendliness as compared to conventional lighting sources such as incandescent and fluorescent lamps and also have wide applications in a variety of fields including in lighting, architectural and medical etc. Among the various applications, the lighting sector is one of the most important fields because it consumes a large amount of electricity. About 15-22% of total electricity production in the world is consumed in the lighting sector. Therefore, understanding how to fabricate a white light-emitting diode is very necessary in order to improve its practical application further. Basically, there are two methods of fabrication for white light emitting diode, mixing of multiple LEDs and phosphor converted white light emitting diode (pc-WLED). The luminous efficiency and rendering index is influenced by the type of fabrication. In this chapter, the general introduction of light emitting diode (LED), its working principle, characteristics of light including CIE, color temperature and rendering index, the different modes of fabrication for white light-emitting diodes, and their advantages and disadvantages have been discussed.