William David Coolidge (/ˈkuːlɪdʒ/; October 23, 1873 – February 3, 1975)[1] was an American physicist and engineer, who made major contributions to X-ray machines. He was the director of the General Electric Research Laboratory and a vice-president of the corporation. He was also famous for the development of "ductile tungsten", which is important for the incandescent light bulb.
Coolidge went to work as a researcher at General Electric's new research laboratory in 1905, where he conducted experiments that led to the use of tungsten as filaments in light bulbs. He developed 'ductile tungsten', which could be more easily drawn into filaments, by purifying tungsten oxide. Starting in 1911, General Electric marketed lamps using the new metal and they soon became an important source of income for GE. He applied for and received a patent (US#1,082,933) for this 'invention' in 1913. However, in 1928 a US court ruled[2][3][4] that his 1913 patent was not valid as an invention.
Improved X-ray tube
William Coolidge explains medical imaging and X-rays.
In 1913 he invented the Coolidge tube (hot cathode tube), an X-ray tube with an improved cathode for use in X-ray machines that allowed for more intense visualization of deep-seated anatomy and tumors. The Coolidge tube, which also utilized a tungstenfilament, was a major development in the then-nascent medical specialty of radiology (US patent filed in 1913 and granted as US Patent 1,203,495 in 1916). Its basic design is still in use. He also invented the first rotating anode X-ray tube.
Coolidge became director of the GE research laboratory in 1932, and a vice-president of General Electric in 1940, until his retirement in 1944. He continued to consult for GE after retirement.
Patents
Coolidge, U.S. patent 1,082,933, "Tungsten and method of making the same for use as filaments of incandescent electric lamps and for other purposes."
^General Electric Co. v. De Forest Radio Co., 28 F.2d 641, 643 (3rd Cir. 1928)
^Lakshman D. Guruswamy, Jeffrey A. McNeely, Protection of global biodiversity: converging strategies. Duke University Press, 1998, p.333.
^Briant and, C.L.; Bewlay, Bernard P. (1995). "The Coolidge Process for Making Tungsten Ductile: The Foundation of Incandescent Lighting". MRS Bulletin. 20 (8): 67–73. doi:10.1557/S0883769400045164.
^James E. Brittain History William D. Coolidge and Ductile Tungsten in IEEE Industry Applications Magazine, Sept/Oct 2004, page 10
References
Wolff, Michael F. (1984). "William D. Coolidge: Shirt-sleeves manager: Famous for two wide-ranging inventions, this engineer proved himself an innovative manager as he guided the renowned GE Research Laboratory through some of its most turbulent years". IEEE Spectrum. 21 (5): 81–85. doi:10.1109/MSPEC.1984.6370272. ISSN0018-9235. S2CID3204491.*Furfari, F.A.T.; Brittain, J.E. (2004). "History - William D. Coolidge and Ductile Tungsten". IEEE Industry Applications Magazine. 10 (5): 9–10. doi:10.1109/MIA.2004.1330764. ISSN1077-2618. S2CID39008486.
Brittain, J.E. (2006). "Electrical Engineering Hall of Fame: William D. Coolidge". Proceedings of the IEEE. 94 (11): 2045–2048. doi:10.1109/JPROC.2006.885128. ISSN0018-9219.
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