RCA demonstrates electron microscope, April 14, 1940
Vladimir Zworykin (seated) and James Hillier demonstrate an early electron microscope.
Prior to joining RCA, Russian inventor and engineer Vladimir Zworykin, credited as a co-inventor of television, studied electrical engineering at the St. Petersburg State Institute of Technology, graduating in 1912. He emigrated to the United States in 1919 and worked for Westinghouse Electric Company while also earning a Ph.D. in electrical engineering from the University of Pittsburgh. During the 10 years he spent at Westinghouse, Zworykin developed the iconoscope, which produced pictures by scanning images, and the kinescope, which reproduced those scanned images on a picture tube and made electronic television possible.
After Westinghouse executives viewed a demonstration of this new system, however, they decided not to pursue the technology, and Zworykin moved on to RCA as associate research director for the company’s electronic research laboratory in Camden, NJ. He started the EM program at RCA in 1939 and began work on the development of an electron microscope, a type of microscope that uses an electron beam to illuminate a specimen and produce a magnified image.
The concept for such a microscope originated with German physicist Ernst Ruska, who with electrical engineer Max Knoll, also from Germany, built the first prototype in 1931. It had a resolution of only 400 times, which was not as good as that of an optical, or light, microscope, which uses visible light and a system of lenses to magnify images of small samples.
Two years later, Ruska improved on the resolution, making it better than its optical counterparts.
Later in that decade, at the University of Toronto, Canadian-born physicist and inventor James Hillier and fellow researcher Albert Prebus adapted the work of the German scientists and others and developed a prototype of a microscope that sent a stream of electrons through magnetic coils to produce an image 7,000 times the size of the object being studied, much greater than the 2,000 times magnification produced by optical microscopes used at that time.
According to his January 22, 2007 obituary, Hillier took the prototype to RCA in 1940 and “set out to produce a compact microscope that would be cheaper and more effective for biological research.” The obituary continues: “The technology could easily have gone to General Electric, which had recruited Dr. Hillier after his early research, but he said he preferred the emphasis on practical innovation and application he found at RCA.”
RCA’s team, headed by Zworykin, in 1939 built the first model to reach a milestone magnification of 100,000 times. They demonstrated the device in Philadelphia on April 14 of the following year. It measured 10 feet high and weighed half a ton. From 1940 to the 1960s, when RCA ended its production, the company sold approximately 2,000 electron microscopes.
Note: Some sources indicate that the demonstration actually took place April 20. Please chime in below if you have definitive information either way.
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Editor's note: This article was originally posted on April 14, 2014 and edited on April 14, 2017.