Vladimir K. Zworykin - Biography

Biography

Zworykin was born in Murom, Russia, in 1888, on July 29 (old style July 17), to the family of a prosperous merchant. He had a relatively calm upbringing, and he rarely saw his father except on religious holidays. He studied at the St. Petersburg Institute of Technology, under Boris Rosing. He helped Boris Rosing with experimental work on television in the basement of Rosing's private lab at the School of Artillery of Saint Petersburg. Rosing had filed his first patent on a television system in 1907, featuring a very early cathode ray tube as a receiver, and a mechanical device as a transmitter. Its demonstration in 1911, based on an improved design, was among the first demonstrations of TV of any kind.

Zworykin graduated in 1912 and, thereafter, studied X-rays under Professor Paul Langevin in Paris. During World War I, Zworykin was enlisted and served in the Russian Signal Corps, then succeeded in getting a job working for Russian Marconi, testing radio equipment that was being produced for the Russian Army. Zworykin decided to leave 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 decided, this time, 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. 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 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. This would result in the television signal being derived from the modest number of electrons released at the instant the cathode ray swept over an image point.

The demonstration given by Zworykin sometime in late 1925 or early 1926 — not in 1923, as popular accounts would have it — was far from a success with the Westinghouse management, even though it showed the possibilities inherent in a system based on the Braun tube. Although he was told by management to "devote his time to more practical endeavours", Zworykin continued his efforts to perfect his system. As attested to by his own writing, including 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 "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 RCA at their newly established laboratories in Camden, New Jersey.

The move to the 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 80 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 during the entire time between two scansions by the cathode-ray beam.

According to Albert Abramson, Zworykin's experiments started in April 1931, and after the achievement of the first promising experimental transmitters, on October 23, 1931, it was decided that the new camera tube would be named Iconoscope. The system was ready to be launched at the end of 1934, a contract had of course been signed with the Hungarian inventor for the purchase of his patents. In early 1935, the new tube was introduced in Germany. It was soon developed there, with some improvements, and was successfully used at the 1936 Berlin Olympic Games as one of several cameras, including Philo Farnsworth's Image Dissector, for film transmission only, broadcasting the games to some two-hundred public theaters. Although the tube went through a number of adjustments and improvements, it continued to be called by the generic name of Iconoscope.

The developments in England, by the British firm Marconi/EMI, followed the original charge storage design under a patent exchange. This electronic system was officially adopted by the BBC whose experimental public broadcasts began in England in November 1936 and initially included the Baird-system. The British electronic system featured 405 scanning lines, while German television adopted 441 line scanning and so did RCA following the initial (1934) 375 line definition.