Vladimir Kosma Zworykin
Vladimir Kosma Zworykin
Vladimir Kosma Zworykin
Born: 1889
Birthplace: Murom, Russia
Cathode ray tube—Zworykin invented the iconoscope, a television transmitting tube and the
kinescope, a cathode ray tube that projects pictures it receives onto a screen. He also invented
an infrared image tube and helped develop an electron microscope. (1977)
Died: 1982
Zworykin, Vladimir Kosma (zwô'rikin) [key], 1889–1982, American physicist, b. Russia, educated
in Russia, at the Collège de France, and at the Univ. of Pittsburgh (Ph.D., 1926). He became an
American citizen in 1924. On the staff of the Radio Corp. of America after 1929, he became vice
president and technical consultant of the corporation in 1947 and honorary vice president and
consultant in 1954. In recognition of his many achievements he was awarded the National Medal
of Science in 1967. His important researches in electronics enabled him to develop with his
coworkers the iconoscope, a scanning tube for the television camera, and the kinescope, a
cathode-ray tube in the television receiving apparatus. A group under his direction produced
(1939) an electron microscope. Zworykin is coauthor of Photocells and Their Application (1930,
rev. ed. 1934), Television (1940), Electron Optics and the Electron Microscope (1945),
Photoelectricity and Its Application (1949), and Television in Science and Industry (1958).
Russian inventor, Vladimir Zworykin invented the cathode-ray tube called the kinescope
in 1929. The kinescope tube was sorely needed for television. Zworykin was one of the
first to demonstrate a television system with all the features of modern picture tubes.
Zworykin also invented the iconoscope in 1923 - a tube for television transmission used
in the first cameras. The iconoscope was later replaced but it laid the foundations for
early television cameras.
Rosing and Zworykin exhibited a television system in 1910, using a mechanical scanner
in the transmitter and the electronic Braun tube in the receiver.
Rosing disappeared during the Bolshevik Revolution of 1917. Zworykin escaped and
briefly studied X-rays under Paul Langevin in Paris, before moving to the United States
in 1919, to work at the Westinghouse laboratory in Pittsburgh.
Vladimir Zworykin was transferred by Westinghouse to work for the Radio Corporation
of America (RCA) in Camden, New Jersey, as the new director of the Electronic
Research Laboratory. RCA owned most of Westinghouse at that time and had just bought
the Jenkin's Television Company, makers of mechanical television systems, in order to
receive their patents (see C. F. Jenkins).
Zworykin made improvements to his iconoscope, RCA funded his research to the tune of
$150,000. The further improvements allegedly used an imaging section which was
similar to Philo Farnsworth's patented dissector. Patent litigation forced RCA to start
paying Farnsworth royalties.
The lure of theoretical physics drew Zworykin to Paris after he graduated the St.
Petersburg Institute of Technology with honors and a scholarship in electrical
engineering in 1912. There he studied X-rays under Paul Langevin at the Collegè de
France (1912-1914), in Paris. Then he went to Berlin to continue studies in physics.
When the First World War broke out in August 1914, he was evicted from Germany as
an enemy alien and returned to Russia.
Zworykin served during World War I in the Russian Signal Corps. In 1916 Zworykin
married Tatiana Vasilieff (later they were divorced) and they had two children. Rosing
disappeared during the Bolshevik Revolution of 1917. Soon Zworykin also decided to
leave Russia for the United States. He emigrated to the United States in 1919 and became
a naturalized citizen in 1924.
During the first half of 1932, an experimental television system had been used in New
York using a studio scanning apparatus. This consisted of a mechanical disk, flying-spot
type, for an image of 120 lines. Even for small areas of coverage and for 120 lines, the
resulting signal amplitude was unsatisfactory. In the Camden system, an iconoscope was
used as the pick-up device. The use of the iconoscope permitted transmission of greater
detail, outdoor pick-up, and wider areas of coverage in the studio. Experience indicated
that it provided a new degree of flexibility in pick-up performance, thereby removing one
of the most technical obstacles to television.
Zworykin was not alone. By 1934 two British electronic firms, EMI and Marconi, created
an all-electronic television system. They used the Orthicon camera tube invented by an
American company, RCA. This electronic system was officially adopted by the BBC in
1936. It consisted of 405 scanning lines, changing at twenty five frames per second.
The further improvements allegedly used
an imaging section which was similar to
Philo Farnsworth's patented dissector.
Patent litigation forced RCA to start paying
Farnsworth royalties. Both Farnsworth and
Zworykin, working separately, made great
advances towards commercial television
and affordable TV sets. By 1935, both were
broadcasting intermittently, using all-
electronic systems. But Baird Television
was first in 1928 with an all mechanical
television system.
Screen image of Dr. V. K. Zworykin
His other developments in electronics include an early form of the electric eye and
innovations in the electron microscope. His work led to text readers, electric eyes used in
security systems and garage door openers, and electronically-controlled missiles and
vehicles. Working with James Hiller, Zworykin also began to apply television technology
to microscopy, which led to RCA's development of the electron microscope in 1939. In
1930, Zworykin's experiments with G.A. Morton on infrared rays led to the development
of night-seeing devices. His electron image tube, sensitive to infrared light, was the basis
for the sniperscope and the snooperscope, devices first used in World War II for seeing in
the dark. His secondary-emission multiplier was used in the scintillation counter, one of
the most sensitive of radiation detectors. During World War II he advised several defense
organizations, and immediately after the war, he worked with Princeton professor John
von Neumann to develop computer applications for accurate weather forecasting. In 1957
Zworykin patented a device that used ultraviolet light and television to throw a colour
picture of living cells on a screen. This paved the way for new biological investigations to
take place.
Iconoscope, model 1846, was used in a television guided bomb during the latter part
of WW2.
After retiring from RCA in 1954, he was named an honorary vice president of RCA and
its technical consultant. He was also appointed director of the Rockefeller Institute for
Medical Research (now Rockefeller University) in New York and worked on
electronically based medical applications.
When an optical image is focussed on the treated mosaic, the whole surface assumes a
distribution of positive charge that corresponds to the distribution of light in the image.
The amount of charge at each point on the surface steadily increases, if the optical image
is maintained, until the scanning spot passes over the globule of silver at that point.
As each globule is passed over by the beam, it undergoes a sudden change in electrical
potential, the amount of the change being proportional to the light falling on it. The
change in potential of the globule is transferred through the mica support to the signal
plate behind it, the globule and plate forming in effect the plates of an electrical
capacitor. Thus, as the beam passes in succession over the globules lying along a given
scanning line, the signal plate assumes a succession of voltages (the picture signal) that
match the corresponding succession of light values along that line. The signal plate is
connected to an amplifier, external to the iconoscope, that increases the strength of the
picture signal.
The phenomenon of charge storage, by which the magnitude of the electrical image is
continually increased between successive scannings of each line, is of the utmost
significance in television technology. The spirally apertured rotating Nipkow disk (and
other non-storage television pickup devices) employs only the light that is present at a
given point in the image at the instant the scanning spot passes over that point. Since in
modern television the area of the scanning spot is only about one two-hundred-
thousandth of the area of the scanning pattern, only this small fraction of the light of the
image can be used. But when the image charge is stored in increasing amount for the full
interval between successive scannings of a given point, the accumulated charge is then
theoretically increased by about 200,000 times the single charge that can be accumulated
during the time the beam moves through its own width.
The iconoscope was later replaced but it laid the foundations for early television cameras.
FURTHER READING
Abramson, Albert. Zworykin, Pioneer of Television. Urbana: University of Illinois
Press, 1995.
Cheek, Dennis W., and A. Kim, Vladimir Zworykin. In McMurray, Emily J., editor.
Notable
Twentieth-Century Scientists, Volume 4. Detroit, Michigan: Gale Research, 1995.
Parker, Sybil P., editor. McGraw-Hill, Modern Scientists and Engineers, Volume 3.
New York: McGraw Hill, 1980.
Thomas, Robert M. Jr., Vladimir Zworykin, Television Pioneer, Dies at 92. New York
Times
Biographical Service, August 1982.
In the Internet: Interview with Vladimir Zworykin (1975)
History of TV - very detailed story!
This text has been compiled from the biographies of Zworykin available in the Internet:
( 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 ).
Many pictures used in this page have been taken from the web site:
http://historytv.net and I am very grateful to Mr. Steve Restelli for the kind
permission to use them.