In the lighting industry, right now there are two words that are dominating many of the illumination choices contractors and building owners are making right now -- energy efficiency. The new technology that is driving that trend are LED lights.
After all, the more efficient a light is the longer it will last and the less energy it will need to use to offer high-quality light. All of these things will equal cost savings in the long run for everyone involved. Who would not like that?
In the world of energy efficiency lighting, right now LED lights are quickly growing in popularity. Before now, LED lights were mainly for applications like traffic lights and in electronic gadgets. Advances in LED light technology are beginning to allow LED lights to work in residential and commercial applications. This makes them a viable substitute for traditional incandescent and fluorescent lighting.
History of LED Lights
LED lights can trace their roots all the way back to 1907, when a scientist by the name of H.J. Round -- an assistant of inventor Guglielmo Marconi -- identified a phenomenon known as electro-luminescence. This experience is both optical and electrical, and happens when an electrical current passes through a certain material, and that material illuminates because of it. In this case, Round was working with silicon carbide, which is the substance that created light when electricity ran through it -- the color of the light would change depending on how much voltage he used.
After that, it wasn't until the 1920s that more research was done on electro-luminescence. This time it was by a Russian researcher by the name of Oleg Vladimirovich Losev, who in 1927 had his research published on his work with, again, silicon carbide and electro-luminescence.
Although Losev did not invent LED lights, his research helped pave the way for those that did. That day finally came in 1961 by two American inventors from Texas Instruments -- Robert Biard and Gary Pittman. The duo invented the infrared LED by accident when trying to make something else. Here it was gallium arsenide (GaAs) -- a compound of arsenic and gallium -- that the inventors found would emit light when an electrical current passes through it.
In 1962, Pittman and Biard filed their patent for their discovery, and they were given the first-ever patent for what we know today as the LED light. Then later that year, Texas Instruments began to manufacture LED products for commercial applications.
Invisible LED Light
An interesting thing to note is that the LED lights that Pittman and Biard invented emit infrared light. That means no humans could actually see the light it was making. It was, in 1962 that the first visible light LED - a red one - was created. This time it was by Nick Holonyack at General Electric. Then in later years, other inventors created other color LED lights. For example, the yellow-colored LED was invented in 1972 by M. George Craford for Monsanto Company. In 1991 the white LED was developed by Naruhito Iwasa at chemical company Nichia. In 1994 the blue LED was invented by Shuji Nakamura in Japan.
How LED Lights Work
So just how do LED lights work?
In its simplest form, an LED -- or Light Emitting Diode -- is a type of semiconductor that has two terminals and manages the direction light will go. When an electrical current runs through the semiconductor (aka diode), it makes light.
To make the light magic happen, the LED uses a process called p-n junctions. One side of the diode fills with semiconductive substances that have a negative charge, while the other side fills with semiconductive substances. However, this time they have a positive charge. What is keeping these two sides apart is what we call the p-n junction. Additionally, the p-n junction is what keeps the electrical current flowing in only the direction you need it to.
When an electrical current passes through the diode, the material emits electrons on the n-type side. Those electrons get moving, and travel over to the p-type side and literally "fills in" electron holes that are in the positive atoms there. When this filling in happens, those electrons lose some energy, which releases in the form of a photon of light.
The size the photo expels is a factor of how much energy releases. Depending on the frequency of photon you get will regulate what color light you see, or if the light is visible by humans. As we mention earlier, infrared and red LED lights are available through the use of gallium arsenide. If you want to result in a blue colored LED, you would use the compound gallium nitride. And for a white LED, you would use a man-made crystalline substance called yttrium aluminum garnet.
LED Lighting: Lamps
So just how does all this work in an LED lamp?
Unlike a conventional incandescent light bulb, an LED lamp does not use a filament that glows when hot and emits light. Instead, one LED lamp consists of a bunch of small LEDs into a bulb product that screw into a light socket. Or, a tube product that can replace fluorescent lighting.
Generally speaking, an LED lamp can replace incandescent bulbs from 5 to 60 watts. Most use a base that makes it compatible with standard light bulb sockets. Additionally, some types of LED lamps are dimmable, and others are available in a variety of different color combination options.
For LED tube lamps, these can be used to replace fluorescent T8, T10 or T12 lamps. They are normally available in 2, 4 and 8-foot sizes. Some LED tubes can just be dropped right into existing fixtures. Others may require some rewiring and removal of the ballast.