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Dr. Julius Edgar Lilienfeld

Dr. Julius Edgar Lilienfeld was a German scientist who worked at the University of Leipzig before immigrating to the U.S. in the 1920's (due to the increasing persecution of Jews in Germany). Lilienfeld operated the first large scale hydrogen liquification facility in Germany. The liquid product was used to fill Zepplins and for cryogenic research. He obtained a U.S. patent on the cryogenic separation of gases in 1915 (patent #1,163,423, filed Dec. 7, 1911). Lilienfeld. developed and patented several X-ray tubes around 1920, which placed him in direct conflict with Coolidge at G.E. (an excellent piece on the X-ray tube development has been published by Prof. Robert G. Arns, Univeristy of Vermont in Burlington). Some of his X-ray tube patent numbers are: #1,559,714, #1,559,715, #1,578,045, #1,122,011, #1,218,423, and #1,979,275.

During 1925-1928, Lilienfeld developed and patented several devices which would now be referred to as field effect or point junction transistors. Shockly's original field effect transistor patent was completely thrown out and Bardeen's point junction patent transistor patent had over half the claims dismissed due to Lilienfeld's prior work. Lilienfeld's transistor patent numbers are:  #1,745,175, #1,900,018, and #1,877,140. Some of the constructions shown in the patents have been reproduced by Prof. Arns and a grad student, Bret Crawford, at U.Vermont, Burlington, and by Prof. Joel Ross, St. Michael's College, Vermont. While the devices did not perform to today's standards, signal amplification was detected. The exact construction employed and performance obtained by Lilienfeld remain unknown.

During the late 1920's Lilienfeld. worked for the AMRAD Corp., Medford, Mass., where he was head of capacitor engineering and conducted basic research in electrolytic capacitor chemistry and physics. He purchased the engineering portion of the plant in 1930, renaming it the Ergon Laboratories. There is some evidence that his capacitor work may have led to the transistor discovery/invention as Lilienfeld patented the first solid state electrolytic capacitor (#1,906,691, filed on March 28, 1928) and a solid state rectifier in 1926 (patent #1,611,653). J.E.L. gave a 49 page paper on electrolytic capacitors before the Electrochemical Society in 1930, with two shorter papers in 1932 and 1935. The fundamental theories and practice laid out in these papers remains in use to the present day for aluminum capacitors (a $6,000,000,000/year business world wide).

Lilienfeld also developed many other, though less spectacular inventions, such as a loudspeaker (patent #1,723,244), a spark plug (patent #2,015,482), vacuum tube seals (patent #2,015,483 and #2,015,484), a pupillograph for eye examinations (patent #2,445,787), motion picture camera for industrial use (patent #2,521,734), elastic fabrics and garments (patents #2,570,352, #2,659956, #2,627,603,  #2,659,957, #2,700,317, and #2,880,730), fabric furniture (patents #2,891,603 and #2,907,376), and many improvements in electrolytic capacitor construction, electrolytes, foil anodizing methods, and assembly techniques.

Lilienfeld died in 1963, at the age of 82.

The above informatiion on Dr. Julius Edgar Lilienfeld was provided by Brian Melody.

To recognize a most outstanding contribution to physics. The prize was established by the APS Council in 1988 under the terms of a bequest of Beatrice Lilienfeld in memory of her husband, Julius Edgar Lilienfeld.

©Mary Bellis

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