The History of Fluorescent Lights

How were fluorescent lights and lamps developed? ​When most people think of lighting and lamps, they think of the incandescent light bulb developed by Thomas Edison and other inventors. Incandescent light bulbs work by using electricity and a filament. Heated by electricity, the filament inside the light bulb exhibits resistance that results in high temperatures that cause the filament to glow and emit light.

Arc or vapor lamps work differently (fluorescents fall under this category), the light is not created from heat, the light is created from the chemical reactions that occur when electricity is applied to different gases enclosed in a glass vacuum chamber.

The Development of Fluorescent Lights

In 1857, the French physicist Alexandre E. Becquerel who had investigated the phenomena of fluorescence and phosphorescence theorized about the building of fluorescent tubes similar to those made today. Alexandre Becquerel experimented with coating electric discharge tubes with luminescent materials, a process that was further developed in later fluorescent lamps.

American Peter Cooper Hewitt (1861-1921) patented (U.S. patent 889,692) the first mercury vapor lamp in 1901. The low-pressure mercury arc lamp of Peter Cooper Hewitt is the very first prototype of today's modern fluorescent lights. A fluorescent light is a type of electric lamp that excites mercury vapor to create luminescence.
The Smithsonian Institute says that Hewitt built on the work of German physicist Julius Plucker and glassblower Heinrich Geissler. Those two men passed an electric current through a glass tube containing tiny amounts of gas and made light. Hewitt worked with mercury-filled tubes in the late 1890s and found that they gave off abundant but unappealing bluish-green light.

Hewitt didn't think people would want lamps with blue-green light in their homes, so he looked for other applications for it in photographic studios and industrial uses. George Westinghouse and Peter Cooper Hewitt formed the Westinghouse-controlled Cooper Hewitt Electric Company to produce the first commercial mercury lamps.

Marty Goodman in his History of Electric Lighting cites Hewitt as inventing the first enclosed arc-type lamp using metal vapor in 1901. It was a low-pressure mercury arc lamp. In 1934, Edmund Germer created a high-pressure arc lamp that could handle a lot more power in a smaller space. Hewitt's low-pressure mercury arc lamp put off a large amount of ultraviolet light. Germer and others coated the inside of the light bulb with a fluorescent chemical that absorbed UV light and re-radiated that energy as visible light. In this way, it became an efficient light source.

Edmund Germer, Friedrich Meyer, Hans Spanner, Edmund Germer: Fluorescent Lamp Patent U.S. 2,182,732

Edmund Germer (1901-1987) invented a high-pressure vapor lamp, his development of the improved fluorescent lamp and the high-pressure mercury-vapor lamp allowed for more economical lighting with less heat.

Edmund Germer was born in Berlin, Germany, and educated at the University of Berlin, earning a doctorate in lighting technology. Together with Friedrich Meyer and Hans Spanner, Edmund Germer patented an experimental fluorescent lamp in 1927.

Edmund Germer is credited by some historians as being the inventor of the first true fluorescent lamp. However, it can be argued that fluorescent lamps have a long history of development before Germer.

George Inman and Richard Thayer: The First Commercial Fluorescent Lamp

George Inman led a group of General Electric scientists researching an improved and practical fluorescent lamp. Under pressure from many competing companies, the team designed the first practical and viable fluorescent lamp (U.S. Patent No. 2,259,040) that was first sold in 1938. It should be noted that General Electric bought the patent rights to Edmund Germer's earlier patent.

According to The GE Fluorescent Lamp Pioneers, "On Oct 14, 1941, U.S. Patent No. 2,259,040 was issued to George E. Inman; the filing date was Apr 22, 1936. It has generally been regarded as the foundation patent. However, some companies were working on the lamp at the same time as GE, and some individuals had already filed for patents. GE strengthened its position when it purchased a German patent that preceded Inman's. GE paid $180,000 for U.S. Patent No 2,182,732 that had been issued to Friedrich Meyer, Hans J. Spanner, and Edmund Germer. While one might argue the real inventor of the fluorescent lamp, it is clear that GE was the first to introduce it."

Other Inventors

Several other inventors patented versions of the fluorescent lamp, including Thomas Edison. He filed a patent (U.S. Patent 865,367) on May 9, 1896, for a fluorescent lamp that was never sold. However, he did not use mercury vapor to excite the phosphor. His lamp used x-rays.