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A History of Blue Light Part 1 – The Lightbulb

February 01, 2017

A History of Blue Light Part 1 – The Lightbulb

We’ve talked a bit before about how PupilBox intends to enact a paradigm shift in the way that we think about Blue Light. Just in the same way that sunscreen, high SPF clothing, hats, and polarized sunglasses are considered necessities in protecting us from UV radiation, PupilBox knows that our products are going to be considered the standard from protecting the public from the harmful effects of Blue Light. In order to understand why we need this shift, though, it makes sense to understand a bit more about the history of how Blue Light has come into every aspect of our lives over the past 150 years.

If you read our article, Let’s Talk about Sleep, you’ll remember how we discussed that before the advent of the lightbulb, we as humans weren’t exposed to hardly any blue light beyond that of the natural levels of the sun. Our fires and lanterns emitted mostly yellow and orange light, and the sunsets and sunrise also emit mostly red, orange, yellow, and even purple light. It wasn’t until we started to introduce electric light that we found ourselves rubbing our eyes.

History of the Light Bulb

1879- The Incandescent Bulb
The early incandescent light bulb was an introduction into unnatural levels of light. The first incandescent bulbs were invented by Joseph Wilson Swan and Thomas Edison. They operate by running an electric current through a tungsten filament to heat it to the point of light production. The bulbs are normally filled with either an inert gas or a vacuum in order to prevent the filament from evaporating. Incandescent bulbs emit most of their light around the 460nm mark.

1938- The Fluorescent Bulb
Michael Faraday and James Maxwell observed the properties of fluorescence in certain rocks (namely fluorite, from which the term is derived) as early as 1840s. In 1856, german glassblower Heinrich Geissler created the “Geissler Tube,” which involved utilizing a mercury vacuum pump, allowing him to fill a glass tube with mercury gas. He found that when he passed an electric current through his tube, it emitted a strong, green glow. The Geissler tube, however, didn’t truly emit high enough levels of light for it to be used for illumination, but rather solely for amusement. That being said, the Fluorescent light bulb was born. Fluorescent bulbs emit light with a large spike around 440 nm, and interesting again right at the 480-490 mark. This means that fluorescent lighting is not only causing digital eye strain, but it is also affecting your sleep!

In 1938, General Electric commercialized the fluorescent bulb by filing a patent in the name of one of their engineers, Leroy J. Buttolph. Over the years, numerous competing patents were filed and awarded, and by 1951 fluorescent lamps far outnumbered the amount of incandescent bulbs in the marketplace.

In order to get away from the early green glows of the Geissler-tube-type bulbs, a mixture of zinc orthosilicate and beryllium was used inside of the bulbs. Eventually, beryllium was discovered to be toxic, which is why the bulbs we use today contain mostly halophosphate and magnesium tungstate. This yields the bright blue-white light that we see in offices, schools, and those oh-too-bright headlights Audis and BMWs.

Up Next: A Brief History of the Television and Computer Screens

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