Zworykin

NAME: Zworykin, Vladimir Kosma

ACHIEVEMENT(S): TV

NICKNAME/ALIAS: None

DATE/PLACE OF BIRTH: 30 July 1889, at Mourom, Russia

DATE/PLACE/AGE AT DEATH: 29 July 1982, in Princeton, NJ.  Aged 92

DISCIPLINE: Inventor

FIELD: Electrical engineering

LANGUAGE: Russian and English

PARENTS: Kosma A. Zworykin and Elaine Zworykin (distant cousins)

SIBLINGS: ?

SPOUSE: Tatiana Vasilieff, married 1916-51; Katherine Polevitsky, married

1951

CHILDREN: Two children

EDUCATION: St. Petersburg Institute of Technology, 1906-12; College de

France, Paris, 1912-14

MAJOR WORK: 'Television: The Electronics of Image Transmission', 1940

LIFE AND TIMES:

Zworykin received his degree in electrical engineering from St. Petersburg in 1912, and then moved to Paris, where he studied X-ray technology under <taught by> Langevin* at the College de France. Although planning to continue his studies in Berlin, the outbreak of World War I intervened, and in 1914 Zworykin returned to Russia and enlisted a radio officer in the Russian Signal Corps under the command of the electrical engineer <served under> Tykociner*.  

In August 1919 he and his family emigrated to the United States.  In 1920 he was offered a job at the research laboratories of the Westinghouse Electric Corporation in Pittsburgh, Pennsylvania working on the development of radio tubes and photoelectric cells (small devices whose electrical properties are modified by the action of light). 

Dissatisfied with his low salary, a year later Zworykin resigned and took a job in Kansas City, Missouri, but in 1923 he was rehired by Westinghouse with a substantial salary increase and his own laboratory. In 1924 he became a naturalized American and began work on a Ph.D. in physics at the University of Pittsburgh, on the improvement of photoelectric cells.

Zworykin was by now most interested in the concept of television, and in December 1923 he filed a patent application (not granted until 1938) for his iconoscope, or television

transmission tube, an invention that would revolutionize the development of television.  Up to this point, most television research (including that of the English television pioneer <work related to> John Logie Baird*) involved mechanical systems which relied on a rapidly rotating disc (the <work related to> Nipkow* disc) perforated in spirals. 

Light was transmitted from a photoelectric device, to form a series of successive parallel lines on a viewing screen.   The amount of light transmitted for each picture was very small, making the pictures dim and lacking in detail.

Zworykin's iconoscope was an attempt to reproduce the human eye electronically.

[In human vision, light enters the eye through the iris, passes through a lens, and focuses an image on the retina, which registers colours via photosensitive receptor cells (known as cones) and light intensities via cells (known as rods). The optic nerves then transmit this information to the brain in the form of electrical impulses which register as an image.] 

The iconoscope, like the eye, used a lens to focus an image on a mica sheet inside the cathode-ray tube, covered with tiny dots of photoelectric cells which were activated by the image, the light altering the voltage stored on each photoelectric cell.  Simultaneously, an electron beam scanned the mica sheet from top to bottom in parallel lines,  detecting the electrical emissions from each cell in turn. As the beam passed, it restored the voltage of the cell to its original value. The voltage was detected by a metal pick-up plate on the back of the mica sheet, and a voltage from the plate was amplified to

form the television picture signal. The signal could then drive a nearby receiver directly, or it could be transmitted in coded form down a cable, or by radio to a distant television set. 

Developing the work of the Scottish physicist <work related to> Swinton*, who in 1908-11 first proposed the idea of a completely electronic television system, Zworykin next constructed a special kind of cathode-ray tube, which he named the kinescope, which could send a steady stream of electrons to the signal plate.

Within the kinescope, an electron beam is applied to an electrode grid (invented in 1906 by <used work by> De Forest*), with modulation occurring through the use of electromagnetic fields.   In 1924 Zworykin filed an application for a patent for his kinescope, or picture tube, and with these two inventions had produced the first workable all-electronic television system.

In late 1924 Zworykin demonstrated his new system to Westinghouse executives, but they were discouraged by the number of technological problems and decided not to pursue his ideas.  Zworykin continued his research privately, and in 1925 filed his first

patent for colour television; he planned to cover the screen of the cathode-ray tube with a matching pattern in the camera, but work along these lines was not successful, and electronic colour systems were not developed until 25 years later.

In November 1929, after a trip to Europe to learn of developments there, Zworykin demonstrated an improved electronic television system to the Institute of Radio Engineers (IRE) in Rochester, New York.  

Present at the meeting was David Sarnoff, another Russian immigrant who was vice-president of the Radio Corporation of America (RCA) at Camden, New Jersey, who was so impressed by Zworykin's work that he immediately hired him away from Westinghouse, and by the spring of 1930 Zworykin was assistant research director of the RCA electronic research laboratory. 

By April 1933, Zworykin had perfected the iconoscope, or camera tube, which was an improvement on his own 1923 device and that of  <visited> Farnsworth*, another television inventor Zworykin had visited in San Francisco in 1930 (and who had himself by this time developed a workable, all-electronic television system).

Zworykin had successfully ushered in the age of modern television, and in 1940 published his famous work, 'Television: The Electronics of Image Transmission'. The iconoscope was the basis for further important developments in <perfected development of> TV* cameras, while the modern television picture tube is basically Zworykin's kinescope.

ASSESSMENT: He received more than 120 patents on a wide variety of electronic devices and applied many of the principles from his work with television to microscopy, work which led directly to the development of the electron microscope, a key tool in the development of molecular biology and microbiological research.

EXTRA CONNECTIONS: His work related to that of <work related to> Braun*

ONELINER:  Vladimir Zworykin, TV pioneer

BIBLIOGRAPHY:

EB

Abramson, Albert, Zworykin: Pioneer of Television, London, 1995