An LED bulb is a Light Emitting Diode

Photo of Dr. Nick Holonyak, General Electric scientist

Dr. Nick Holonyak Discover devises a light-emitting diode-based laser while working for General Electric in 1962

You probably have already seen an LED before though you may not have known what it is. Just look down at that flickering green light that tells you your computer is doing something underneath the plastic casing. That is an LED or light emitting diode. Now an LED bulb is a light bulb that relies on an light emitting diode to produce enough light to function like a conventional bulb. These bulbs usually consist of 4 parts: the external casing, a mini-circuit board that consisting of diodes and resistors, a heat sink and optics. The circuit board controls the flow of electric current through the lamp both in terms of direction and the amount of voltage allowed. The heat sink is usually made of aluminum and functions to cool the bulb, although LED bulbs are known to produce far less heat than ordinary bulbs.

Photo of Henry Round

Henry Round discovered the light-generating properties of raw silicon carbide

LED bulbs are built from light emitting diodes, but what is an LED and where did they come from? Though the first practical LED was born in General Electric’s laboratories in 1962, a man named Henry Round had already discovered the light-generating properties of raw silicon carbide in 1907 as he was working on diodes for radio transmission. He noted glows of different colors at different voltages as current passed across the silicon carbide junction. But it was not until 1962 that GE’s Dr. Nick Holonyak devised a visible LED-based laser that would be the basis of all today’s usages of LEDs. Others research groups had come up with LEDs earlier but they were all infrared. Inspired by Dr. Holonyak’s discovery, George Cradford, a University of Illinois researcher, came up with orange, yellow and green LEDs in 1967.

However, the world would have to wait two more decades before the first LEDs bright enough to function as light bulbs were made. The invention of these LEDs was credited to Stanley Electric. But white LEDs did not become a reality until the 1990s when a researcher from a relatively obscure chemical company in Japan discovered a production-compatible way of making the diodes. By 1995, Nichia researchers had discovered a type of phosphor that could be combined with a blue LED die to produce a white LED. Despite the fact these discoveries were made a while back, mass production of white LEDs is only just taking off. Japanese electronics giant Toshiba, for instance, has announced plans to begin such production towards the end of 2012.

It is a fact that some governments, in embracing the ‘green’ ethos, have begun putting in place measures to phase out the incandescent bulbs that have been the norm in homes for so many years. They are doing this by introducing legislation that establishes energy efficiency standards. LED bulbs are among lighting technologies that are being touted as replacements for conventional lights. However, skeptics argue that people will be slow in embracing this type of energy saving light bulbs because of the perceived high cost. An ordinary bulb costs less than a dollar but an LED bulb could go for as much as $30. But one should consider the fact that after making that initial purchase, they will not be replacing the bulb for as many as 20 years. And research on LED lighting is still ongoing and as such consumers can be assured there will be more pocket-friendly LED bulbs on supermarket shelves soon.