What is an LED Anyway?

Thursday, March 21, 2013


If you asked most people a few years ago what LED stands for most wouldn’t know the answer.  Ask the same question now and lots of folks actually know what it means, Light Emitting Diode.  The growing popularity of LEDs is due to a few factors. The automotive industry has pushed LED technology due to their usage in brake and headlights. Also, many people are now buying electronics with them inside, like TVs, smartphones and computers. Most manufacturers of home lighting offer equivalents in LED of up to 100 watts in light output while using only 20 watts.

LEDs are usually very small modules of silicon carbide that create light from a charged reaction of indium, gallium and nitrogen. The light that is created for white LEDs actually starts out as blue. This blue light is passed through a phosphor that usually looks yellow in color. Once the blue light is passed through the phosphor it creates white light. From a fixture manufacturing standpoint, getting the color temperature right is the tricky part. At this point LEDs are binned into their different colors of lights after testing. Manufacturers then choose the colors that they want to use in their fixtures, whether it be warmer or cooler.

The phosphor lens can be applied in two ways, directly on the LED or as a separate lens known as a remote phosphor method. Remote phosphor allows for multiple blue LEDs to be arranged under a single lens, which evens out the color temperate and reduces complexity.

LEDs come in small packages, so manufacturers use them in multiples to achieve high output levels in a single product.  When using them in singles or multiples they are driven by a circuit and driver, which control the current and voltage entering the LED. Different LEDs need different amounts of voltage and current depending on their specifications.

Overall LEDs are fascinating little emitters of light that are making energy consumption much more efficient. Just like the constant push for faster microprocessors, LEDs are now in a race to push more light while using less energy. With technology emerging quickly, it looks like the future holds nothing but advances in efficient lighting.