LED, or Light Emitting Diodes, Light Bulbs represent one of the recent inventions in science that is predicted to curb down the pollution caused by incandescent light bulbs or gas-based illuminating devices. The use of LED light is evident from the numbers on digital LED clocks, the transmittal of information through remote control, light up watches, illuminating the traffic lights, and even forming images on the big television screens.

Before we understand how LED produces light, it won’t be out of place to learn some facts about light itself. In its minutest sense, light is a form of energy that is released by a single atom. This energy comprised of tiny particles, called photons that have energy and momentum, but no mass. The cause of release of this energy is the movement of electrons within the atom. These electrons move in orbits around the nucleus of an atom, and the electrons with more energy tend to move farther away from the nucleus. As a corollary, when the electrons that are farther from the nucleus tend to come closer, they release energy in the form of a photon. The rule is greater the energy drop of an electron, higher the energy of a photon.

The LED light bulbs are tiny bulbs that fit easily into an electric circuit and do not use any filament to burn, as is the case with incandescent bulbs. LEDs are semiconductor diodes, which use electronic chip to create a positive-negative junction, which ultimately leads to the production of light. The process is explained thus.

Upon providing power to the diode, a current flows from the anode (positive) to the cathode (negative). This results in the flow of electrons and electron holes into the junction from electrodes. Now, when an electron meets a hole, it creates a lower energy level that provides energy as light.

A single LED can produce a small amount of light of single colour at a time. Different colours of light can be achieved using different techniques. These include:

1. Wavelength Conversion by converting some or all of the LED’s output into visible wavelengths.
2. Colour Mixing by using multiple colours of LEDs in a lamp to produce the desired colour of light.