Related History - The History of Lighting

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 states that, "Electrical inventor, Peter Cooper Hewitt built on the mid-19th century work of German physicist Julius Plucker and glassblower Heinrich Geissler. By passing an electric current through a glass tube containing tiny amounts of a gas, Plucker and Geissler found they could make light. Peter Cooper Hewitt began developing mercury-filled tubes in the late 1890s, and found that they gave off an unappealing bluish-green light. The amount of light, however, was startling. Hewitt realized that few people would want his lamps in their homes, and so concentrated on developing a product for other uses." That purpose turned out to be lighting for photographic studios and industrial use. 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 states, "In 1901, a now-forgotten inventor named Peter Cooper Hewitt invented an arc lamp that used mercury vapor. The vapor was enclosed in a glass bulb. This was the first enclosed arc-type lamp using metal vapor. In 1934, a high pressure variant of this was developed [by Edmund Germer], which could handle a lot more power in a smaller space...

...The low pressure mercury arc lamp of Peter Cooper Hewitt is the very direct parent of today's modern fluorescent lights. It was found that these low pressure [mercury] arc lamps would put out large amounts of ultra-violet light. Folks then figured that if they coated the inside of the light bulb with a fluorescent chemical (one that absorbed UV light and re-radiated that energy as visible light) they could make 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 prior to Germer.

George Inman and Richard Thayer - The First Commercial Fluorescent Lamp

George Inman lead 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."

• Fluorescent Lamps - How They Work
• The Fluorescent Lamp: A Plasma You Can Use
• Edmund Germer
• George Inman and Richard Thayer
• The GE Fluorescent Lamp Pioneers
• Compact Fluorescent: The Challenge of Manufacturing 1970s patents

Other Inventors
Several other inventors patented versions of the fluorescent lamp including:

• Thomas Edison 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.

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