Lighting is the basic need of human beings and in present times it is as important as food, shelter and clean drinking water. Still two billion people, which accounts for one third of the human population do not have access to electricity and are dependent on fuel based lighting. In this era when people are going for space walks and scientists are unraveling the mysteries of the universe, electricity should be considered as a human right as it is directly linked to literacy and education.
The problem of electricity is largely faced by the people living in under developed or developing nations of the world like the African and Asian countries. Besides the problem of no access to electricity (especially in remote rural areas) there is also a problem of frequent power cuts, which is hugely affecting the industries in most of these countries. This is because of greater demand as compared to the supply of electricity. According to an estimate lighting consumes 25 to 30 % of the world’s total electricity production and if this percentage is reduced, much electricity can be saved. Thus there is a need to develop a lighting technology that can illuminate the lives of billions without draining their pockets and Solid - State Lighting seems to be an ideal technology to realize this dream.
Solid – State Lighting is a term used for light emitting sources that use semiconductor materials for emission of light. The two important technologies of solid – state lighting are light emitting diodes (LED’s) and organic light emitting diodes (OLED’s). This technology promises to surpass the energy efficiencies of incandescent bulbs and fluorescent lights. Though LED’s were developed around 40 years ago, but they were generally used in electronic devices like indicator lamps. But due to the recent technological advances they are now widely used in traffic lights, exit signs, cell phones, flashlights, large area outdoor displays (as in Times Square and Las Vegas), etc.
Researches have also indicated that in the near future these lights will be used for illuminating homes and commercial complexes. There are myriad advantages of Solid – State Lighting over conventional lighting systems. LED’s have longer life span than a normal incandescent bulb. They can provide approximately 50,000 hours of life where as an incandescent bulb can last for around 1,000 hours. LED’s are also very energy efficient. The efficiency of lighting is calculated in lumens/watt (light output produced per unit of input electrical power). The lighting efficiency of incandescent bulb is 16 lumen/watt, that of a fluorescent lamp is 85 lumens/watt and of LED’s is 30 lumens/watt. This shows that the luminous efficiency of LED’s is greater than that of incandescent bulbs but less than a fluorescent lamp. The researches going on give a clear indication that in the future the luminous efficiency of LED’s will rise to 150 – 200 lumens/watt.
Besides having longer life and being energy efficient these lighting systems give better quality of light as they have very low ultraviolet and infrared emissions, they are small in size, cool to touch and can easily bear vibrations.
SSL is the future of lighting technology and is an incredible alternative to other lighting systems like incandescent bulbs and fluorescent lamps. This technology is environment friendly, economical and will help people who are still devoid of the most basic needs of livelihood. We can only hope that in days to come whole humanity would benefit from the technological and scientific advancements taking place all over the world.