LEDs Green Devices Of Lighting Technology

A light-emitting diode (LED) is a semiconductor device that emits light when an electric current is passed through it. In this article, Dr Pradeep Kumar Mukherjee discusses the benefits of using LEDs for display and lighting purposes as they indeed prove very cost effective in the long run by saving a lot of energy. He takes us briefly through the history of development of LEDs while dwelling on the overall credentials of LEDs. The author adds a word of caution at the end as most LEDs available in India have high flicker rates not suitable for overall eye health. So, more research is needed on this aspect.

LEDs (light emitting diodes) had been the real heroes in the electronics world, but now they are emerging to take a leading role in the lighting world as well. The lighting systems based on LEDs are extremely energy efficient. They are indeed the green devices of lighting technology. They not only consume less electricity, but also have very long life. That is the reason why LEDs find potential applications in a variety of display devices. They form numbers on the digital clocks. The infrared (IR) LEDs find use in the remote control of TVs and air conditioners that tell you when your appliances are turned on. Coloured LEDs are used in advertisements and sign displays. They can form images on a gigantic TV (called LED TV). LED rope lights and strips are a common sight these days. They are used for a variety of purposes including wedding decorations, concerts, and so on. Alerts and warning signs are also made using these types of lights.

What are LEDs?

Basically, LEDs are just tiny light devices that fit easily into an electrical circuit. They are made of special kinds of materials, called semiconductors. Such materials’ ability to conduct electric current is less than that of conductors. An LED looks like a miniature cup halfway up with two wires, one shorter and another a bit longer protruding through its base. The cup is, in fact, a reflector that holds a semiconductor chip about the size of a grain of sand. This chip is, in fact, the LED’s heart. Inside the chip there is a layer of n-type (negative) semiconducting material that has an excess of electrons. Another layer rests on top and is made of p-type (positive) semiconducting material that has a dearth of electrons or an excess of positively charged particles, known as holes. These p-type and n-type layers form what is called a p-n junction and such a device is known as a junction diode.