Editing Fluorescent lamp (section)

===Commercialization of fluorescent lamps===
All the major features of fluorescent lighting were in place at the end of the 1920s. Decades of invention and development had provided the key components of fluorescent lamps: economically manufactured glass tubing, inert gases for filling the tubes, electrical ballasts, long-lasting electrodes, mercury vapor as a source of luminescence, effective means of producing a reliable electrical discharge, and fluorescent coatings that could be energized by ultraviolet light. At this point, intensive development was more important than basic research.

In 1934, [[Arthur Compton]], a renowned physicist and GE consultant, reported to the GE lamp department on successful experiments with fluorescent lighting at [[General Electric Company plc|General Electric Co., Ltd.]] in Great Britain (unrelated to General Electric in the United States). Stimulated by this report, and with all of the key elements available, a team led by George E. Inman built a prototype fluorescent lamp in 1934 at [[General Electric]]'s [[Nela Park]] (Ohio) engineering laboratory. This was not a trivial exercise; as noted by Arthur A. Bright, "A great deal of experimentation had to be done on lamp sizes and shapes, cathode construction, gas pressures of both argon and mercury vapor, colors of fluorescent powders, methods of attaching them to the inside of the tube, and other details of the lamp and its auxiliaries before the new device was ready for the public."{{sfn|Bright|1949|pp=388–391}}

In addition to having engineers and technicians along with facilities for R&D work on fluorescent lamps, General Electric controlled what it regarded as the key patents covering fluorescent lighting, including the patents originally issued to Hewitt, Moore, and Küch. More important than these was a patent covering an [[electrode]] that did not disintegrate at the gas pressures that ultimately were employed in fluorescent lamps. Albert W. Hull of GE's Schenectady Research Laboratory filed for a patent on this invention in 1927, which was issued in 1931.<ref>{{ref patent| country=US |number=1790153 |status=patent |title=Electrical Discharge Device and Method of Operation |gdate=1931-01-27 |fdate=1927-10-15 |invent1=Albert W. Hull |invent2= |assign1=General Electric Company }}</ref> General Electric used its control of the patents to prevent competition with its incandescent lights and probably delayed the introduction of fluorescent lighting by 20 years. Eventually, war production required 24-hour factories with economical lighting, and fluorescent lights became available.

While the Hull patent gave GE a basis for claiming [[legal]] rights over the fluorescent lamp, a few months after the lamp went into production the firm learned of a U.S. patent application that had been filed in 1927 for the aforementioned "metal vapor lamp" invented in Germany by Meyer, Spanner, and Germer. The patent application indicated that the lamp had been created as a superior means of producing ultraviolet light, but the application also contained a few statements referring to fluorescent illumination. Efforts to obtain a U.S. patent had met with numerous delays, but were it to be granted, the patent might have caused serious difficulties for GE. At first, GE sought to block the issuance of a patent by claiming that priority should go to one of their employees, Leroy J. Buttolph, who according to their claim had invented a fluorescent lamp in 1919 and whose patent application was still pending. GE also had filed a patent application in 1936 in Inman's name to cover the “improvements” wrought by his group. In 1939 GE decided that the claim of Meyer, Spanner, and Germer had some merit, and that in any event a long interference procedure was not in their best interest. They therefore dropped the Buttolph claim and paid $180,000 to acquire the Meyer, et al. application, which at that point was owned by a firm known as Electrons, Inc. The patent was duly awarded in December 1939.<ref>{{ref patent| country=US |number=2182732 |status=patent |title=Metal Vapor Lamp |gdate=1939-12-05 |fdate=1927-12-19  |invent1=Friedrich Meyer |invent2=Hans-Joachim Spanner |invent3=Edmund Germer |assign1=General Electric Company }}</ref>  This patent, along with the Hull patent, put GE on what seemed to be firm legal ground, although it faced years of legal challenges from [[Sylvania Electric Products]], Inc., which claimed [[Patent infringement|infringement]] on patents that it held.

Even though the patent issue was not completely resolved for many years, General Electric's strength in manufacturing and marketing gave it a pre-eminent position in the emerging fluorescent light market. Sales of "fluorescent lumiline lamps" commenced in 1938 when four different sizes of tubes were put on the market. They were used in fixtures manufactured by three leading corporations: [[Lightolier]], [[Artcraft Fluorescent Lighting Corporation]], and Globe Lighting.  The Slimline fluorescent ballast's public introduction in 1946 was by Westinghouse and General Electric and Showcase/Display Case fixtures were introduced by Artcraft Fluorescent Lighting Corporation in 1946.<ref>''Electrical Consultant'', Vol. 50, p. 4, 1946</ref><ref>''Westinghouse Engineer'', Vol. 12–13, p. 141, 1952</ref>  During the following year, GE and [[Westinghouse Electric Corporation (1886)|Westinghouse]] publicized the new lights through exhibitions at the [[1939 New York World's Fair|New York World's Fair]] and the [[Golden Gate International Exposition]] in San Francisco. Fluorescent lighting systems spread rapidly during World War II as wartime manufacturing intensified lighting demand. By 1951 more light was produced in the United States by fluorescent lamps than by incandescent lamps.<ref>{{cite web|url=https://americanhistory.si.edu/lighting/20thcent/prec20.htm|title=Lighting A Revolution: 20th Century Store-room|website=americanhistory.si.edu|access-date=2019-04-26 |archive-date=2018-11-09 |archive-url=https://web.archive.org/web/20181109144831/http://americanhistory.si.edu/lighting/20thcent/prec20.htm|url-status=live}}</ref>

In the first years [[zinc orthosilicate]] with varying content of [[beryllium]] was used as greenish phosphor. Small additions of magnesium tungstate improved the blue portion of the spectrum, yielding acceptable white. After the discovery that [[Berylliosis|beryllium was toxic]], halophosphate-based phosphors dominated.{{sfn|Van Broekhoven|2001|p=[https://books.google.com/books?id=klE5qGAltjAC&pg=PA97 97–98]}}