.
Fluorescent Lights
Inventors: Peter Cooper Hewitt, Edmund Germer, George Inman and
Richard Thayer
by Mary Bellis
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 in a different way (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 a gas and made
light.
Hewitt worked with
mercury-filled tubes in the late 1890’s 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.
Mary Bellis
Mary Bellis
Freelance writer for 18 years on the topic of
inventors
Film producer and director
Experience
Mary Bellis, M.F.A., was a former writer for
ThoughtCo, creating content for 18 years. She was a freelance writer, film
producer, and director. One of her films was a documentary on Alexander
Graham Bell, the inventor of the telephone. She also worked as a curator
specializing in computer generated art.
Education
Mary held a Master of Fine Arts degree
in film and animation from the San Francisco Art Institute.
Awards and Publications
Forbes Best of the Web credited Mary for
creating the number one online destination for information about inventors and
inventions. Her writing has been reprinted and referenced in numerous
educational books and articles.
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