page_title: Vladimir K. Zworykin
section_title: Career
hierarchical_section_title: Vladimir K. Zworykin / Career
caption_attribution_description: Subject: Zworykin, V. K (Vladimir Kosma) 1889-1982 &#160;&#160;&#160;&#160;&#160;&#160;&#160;Birt, Mildred &#160;&#160;&#160;&#160;&#160;&#160;&#160;Westinghouse Electric &amp; Manufacturing Company Type: Black-and-white photographs Date: 1934 Topic: Television Local number: SIA Acc. 90-105 [SIA2010-1667] Summary: Vladimir Kosma Zworykin (1889-1982), a Westinghouse Electric and Manufacturing Company research engineer, is shown demonstrating his new cathode ray television set which can entertain large groups instead of one or two spectators. Miss Mildred Birt is the interested watcher. The broadcast images are projected on a mirror on the top of the cabinet making it possible for many to watch Cite as: Acc. 90-105 - Science Service, Records, 1920s-1970s, Smithsonian Institution Archives Persistent URL:http://siris-archives.si.edu/ipac20/ipac.jsp?&amp;profile=all&amp;source=~!siarchives&amp;uri=full=3100001~!289412~!0#focus Repository:Smithsonian Institution Archives View more collections from the Smithsonian Institution.
context_page_description: Vladimir Kosmich Zworykin was a Russian-American inventor, engineer, and pioneer of television technology. Zworykin invented a television transmitting and receiving system employing cathode ray tubes. He played a role in the practical development of television from the early thirties, including charge storage-type tubes, infrared image tubes and the electron microscope.
context_section_description: Zworykin graduated in 1912. He then studied X-rays under professor Paul Langevin in Paris. During World War I, Zworykin was enlisted and served in the Russian Signal Corps. He then worked testing radio equipment that was being produced for the Russian Army. Zworykin left Russia for the United States in 1918 during the Russian Civil War.  He left through Siberia, travelling north on the River Ob to the Arctic Ocean as part of an expedition led by Russian scientist Innokenty P. Tolmachev, eventually arriving in the US at the end of 1918.  He returned to Omsk, then capital of Admiral Kolchak's government in 1919, via Vladivostok, then to the United States again on official duties from the Omsk government. These duties ended with the collapse of the White movement in Siberia at the death of Kolchak. Zworykin then decided to remain permanently in the US.
  Once in the U.S., Zworykin found work at the Westinghouse laboratories in Pittsburgh where he eventually had an opportunity to engage in television experiments. 
  Zworykin applied for a television patent in the US in 1923. He summarized the resulting invention in two patent applications. The first, entitled "Television Systems", was filed on December 29, 1923, and was followed by a second application in 1925 of essentially the same content, but with minor changes and the addition of a Paget-type RGB raster screen for color transmission and reception. He was awarded a patent for the 1925 application in 1928, and two patents for the 1923 application that was divided in 1931, although the equipment described was never successfully demonstrated. Zworykin described cathode ray tubes as both transmitter and receiver. The operation, whose basic thrust was to prevent the emission of electrons between scansion cycles, was reminiscent of A. A. Campbell Swinton's proposal published in Nature in June 1908.
  The demonstration given (sometime in late 1925 or early 1926) by Zworykin was far from a success with the Westinghouse management, even though it showed the possibilities inherent in a system based on the cathode ray tube. He was told by management to "devote his time to more practical endeavours," yet continued his efforts to perfect his system. 
  As attested  by his doctoral dissertation of 1926, earning him a PhD from the University of Pittsburgh, his experiments were directed at improving the output of photoelectric cells. There were, however, limits to how far one could go along these lines, and so, in 1929, Zworykin returned to vibrating mirrors and facsimile transmission, filing patents describing these. At this time, however, he was also experimenting with an improved cathode ray receiving tube, filing a patent application for this in November 1929, and introducing the new receiver that he named the "kinescope", reading a paper two days later at a convention of the Institute of Radio Engineers.
  Having developed the prototype of the receiver by December, Zworykin met David Sarnoff, who eventually hired him and put him in charge of television development for the Radio Corporation of America (RCA) at its factories and laboratories in Camden, New Jersey.
  The move to the RCA's Camden laboratories occurred in the spring of 1930, and the difficult task of developing a transmitter could begin. There was an in-house evaluation in mid-1930, where the kinescope performed well (but with only 60 lines definition), and the transmitter was still of a mechanical type. A "breakthrough" would come when the Zworykin team decided to develop a new type of cathode ray transmitter, one described in the French and British patents of 1928 priority by the Hungarian inventor Kalman Tihanyi whom the company had approached in July 1930, after the publication of his patents in England and France. This was a curious design, one where the scanning electron beam would strike the photoelectric cell from the same side where the optical image was cast. Even more importantly, it was a system characterized by an operation based on an entirely new principle, the principle of the accumulation and storage of charges dur
caption: Zworykin demonstrates electronic television (1929).
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