LED lights have been used in a variety of applications since their invention in 1961. From inexpensive appliance display lighting to automobile daytime headlamps, light-emitting diodes seem to be everywhere. Indeed, LED lighting could even change air travel as we know it. The 787 Dreamliner, Boeing’s new jetliner, includes LED lighting designed to positively influence passengers’ circadian rhythms.
How could LED lights possibly affect the body’s diurnal rhythms? The answer hinges on the fact that LEDs are “programmable.” Unlike filament-heating incandescent bulbs, LEDs are tiny semi-conductors, fueled by electricity-stimulated electrons crossing a field to fill electron holes. The chemistry here is pretty complex, but suffice it to say that engineers can affect the light wavelengths an LED produces by changing the semi-conductor material. Zinc selenide, for instance, is used to produce blue LED lighting.
Whereas yesterday’s incandescent bulb produced a spectrum of light, each light-emitting diode produces a single wavelength of the designing engineer’s choosing. This quality allows manufacturers to create complex “biological specific” lighting systems, which are based on the science of the body’s natural wake/sleep cycles.
For instance, researchers know that certain wavelengths make people feel sleepy by stimulating melatonin production. Other colors of light tend to make people feel awake and aware. Boeing’s new plane is equipped with an array of mood lighting schemas, from grey-lavender for relaxation to perky orange for meal service. In addition to colors, LED lights can be programmed to dim and brighten at the same rate as the sun would naturally in a full flying day. NASA’s astronauts take advantage of this application while orbiting the globe every 90 minutes on the International Space Station. LED lights offset this biologically confusing situation by simulating a regular day. It is hoped that the LED lights on the Boeing 787 will help reduce passenger jetlag.
But the LED lighting and health revolution won’t stop with the skies. Indeed, we’re probably only a couple of years away from seeing health indications on LED bulb packaging. And LED lights will only continue to be used more and more applications. Retailers are already engineering LED lights to make food seem more appetizing (see: Subway) or jewelry more dazzling. It’s exciting to watch as the tiny light-emitting diode changes the world.