Biography of Vladimir Kosma Zworykin

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Russian-born U.S. electronic engineer, inventor of iconoscope and kinescope (the first transmitter and receiver for TV), and the father of modern television. Most people think of television as a development of the mid-20th century. But as early as 1929 Russian inventor Vladimir Kosma Zworykin was demonstrating a system with all the features of modern picture tubes. Born in Murom, 200 miles east of Moscow, Zworykin was a son of a wealthy merchant, and had an aptitude for science and technology.

Zworykin at age nine started spending summers as an apprentice aboard the boats his father operated on the Oka River. He eagerly helped repair electrical equipment, and it soon became apparent that he was more interested in electricity than anything nautical. At the Imperial Institute of Technology, Boris Rosing, a professor in charge of laboratory projects, became friendly with the young student engineer and let him work on some of his private projects. Rosing was trying to transmit pictures by wire in his own physics laboratory.

He and his young assistant experimented with a primitive cathode-ray tube (CRT), developed in Germany by Karl Ferdinand Braun. In 1910Rosing exhibited a television system, using a mechanical scanner in the transmitter and the electronic Braun tube in the receiver.

The system was primitive but it was more electronic than mechanical.Rosing didn’t have much better luck with his CRT-based television system, though it won a gold medal from the Russian Technical Society in 1912. The real importance of the work was that it left his student Zworykin with a deep interest in the possibilities of the CRT and electron scanning for television systems.

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 anaturalized citizen in 1924.

Just after his arrival to the U.S.A. (1919-1920) Zworykin was a bookkeeper and a financial agent of Russian Embassy in Washington, D.C. In 1920, Zworykin joined Westinghouse Electric Corporation in Pittsburgh to work on the development of radio tubes and photocells. While there, he earned his Ph.D. in physics at the University of Pittsburgh and wrote his dissertation on improving photoelectric cells. Zworykin was determined to build an electronic imaging tube.

After several years of work, he managed to devise a photosensitive plate consisting of tiny droplets of potassium hydride deposited on an insulating substrate of oxidized aluminum. Light falling on the potassium hydride droplets knocked electrons out of them, leaving them with a positive charge. Focusing a image on the plate through a lens left an electrical pattern on the plate that matched the scene.

To read out the pattern of electrical charges, Zworykin took electron gun technology from the CRT and used it to scan across the photosensitive plate. When the electron beam hit a positively charged potassium hydride droplet, the current in the beam increased. The increase in current could be amplified and transmitted.

But electronic television’s development captured his attention. Based on pioneering efforts of Westinghouse in radio, he tried to convince the company to do research in television. Turning down an offer from Warner Brothers, Zworykin worked nights, fashioning his own crudetelevision system.

Zworykin’s 1923 patent

In December 1923 he applied for a patent for the iconoscope, which produced pictures by scanning images. Zworykin called his tube the iconoscope (literally “a viewer of icons”). However, after demonstrating his new system to Westinghouse executives, they decided not to pursue his research. Zworykin describes his 1923 demonstration as “scarcely impressive”.

Westinghouse officials were not prepared to base an investment in television on such a flimsy system. The companys suggestion was that Zworykin devote his time to more practical endeavours. Undeterred, Zworykin continued in his off hours to perfect his system.

He was so persistent that the laboratory guard was instructed to send him home a 2:00 in the morning if the lights of the laboratory were still on. During this time Zworykin managed to develop a more sophisticatedpicture tube called the kinescope which serves as the basis of the television display tubes in use today. Within the year he applied for a patent for the kinescope, which reproduced those scanned images on apicture tube.

These two inventions (iconoscope as a transmitter and kinescope as a receiver) formed the first all-electronic television system. Early conceptions of television focused on a mechanical scanning system with motors and large rotating disks. This type of television generally produced a picture only about one inch square. It was heavy, bulky equipment and certainly not practical for home use. All future television systems would be based on Zworykin’s 1923 patent. He also developed a colour-television system, for which he received a patent in 1928.

On November 18, 1929, at convention of radio engineers in Pittsburgh, Zworykin demonstrated a television receiver containing his ‘kinescope,’ a cathode-ray tube. Zworykin demonstrated his all-electronic television system a full 10 years before it was introduced to the public at the 1939 New York World’s Fair. Zworykin’s all electronic television systemdemonstrated the limitations of the mechanical television system. In attendance was David Sarnoff, president of the Radio Corporation of America (RCA). He was greatly impressed by the television presentation and decided to hire Zworykin to develop his television system for RCA.

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.

Teamed with David Sarnoff at RCA, Zworykin was leading the development of electronic television. When Zworykin started at RCA his system was scanning 50 lines. Experimental broadcasts started in 1930 first using a mechanical camera transmitting at 120 lines. By 1933 a complete electronic system was being employed with a resolution of 240 lines. Reportedly, Zworykin told RCA president David Sarnoff that it would take $100,000 to perfect television. Sarnoff later told the New York Times, “RCA spent $50 million before we ever got a penny back from TV.”

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.

After many years of research and development an all-electronictelevision system emerged from the laboratory in 1933 for actual field tests. These tests were carried out at Camden (New Jersey), using a video transmitter and connected to it by a coaxial line. Iconoscopes (television cameras) were used to pick up scenes both in the studio and out-of-doors.

A scanning pattern of 240 lines made it possible to obtain a picture with good definition, but as the frame frequency was 24 cycles, without interlacing , flicker was quite noticeable. The following year (1934) the number of lines was increased to 343, and an interlaced pattern having a field frequency of 60 cycles and a repetition rate of 30 frames per second was adopted. The results of these tests were so satisfactory that it was decided to continue them in New York City, the site of earlier RCA tests using a mechanical scanner. The advantage of the new location was that transmission studies under more nearly the conditions encountered in actual broadcasts were possible, in particular, with respect to noise and reflection from buildings.

This move was made in 1935, tests followed the following year. The New York studios were located in Radio City. The transmitter was installed in one of the upper floors of the Empire State Building, with the antenna on the mooring mast, 1285 feet above street level. Two links interconnect the studio and transmitter. One of these is an underground coaxial cable approximately a mile in length. An ultra-high-frequency radio relay link operating at 177 megacycles serves as an alternative for interconnecting the two units. In order to increase the flexibility of the system, and to permit outdoor and indoor pickup from remote points, a mobile unit consisting of a pickup truck and transmitter, which operated at 177 megacycles, was placed in service in 1938.

Approximately one hundred receivers were built and located at various points within a radius of 50 miles of the transmitter. These, together with field strength measurements, gave detailed information as to the effect of the terrain on the received pictures. They also facilitated obtaining data on the reaction of a great variety of people to different types of programs.

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.

At the time, very few people had television sets and the viewing experience was less than impressive. The small audience of viewers was watching a blurry picture on a 2 or 3 inch screen. The future of television looked bleak, but the competition for dominance in television broadcasting was hot.

By 1939, RCA and Zworykin were ready for regular programming and they kicked it all off by televising the World’s Fair in New York. Franklin Roosevelt, present at the creation of RCA and a frequent speaker on radio, became the first president to be seen on television when the fair’s opening ceremonies were telecast ten days later. Things moved quickly, and in 1941 the National Television Standards Committee (NTSC) decided it was time to write guidelines for television transmission in the United States. Five months later, all 22 of the nation’s television stations converted to the new electronic standards.

In the early years, during the Great Depression, television sets were too expensive for most of the public. When prices eventually dropped, the U.S. was knee-deep in World War Two. But when a new age dawned after the war, the time was right for the Golden Age of Television. Unfortunately, everyone had to watch it in black and white.

Zworykin’s television system provided the impetus for the development of modern television as an entertainment and education medium. Although ultimately replaced by the orthicon and image orthicon ubes, the iconoscope was the basis for further important developments in television cameras. The modern television picture tube is basically Zworykin’s kinescope.

In later life Zworykin lamented the way television had been abused to titillate and trivialize subjects rather than for the educational and cultural enrichment of audiences. “I hate what they’ve done to my child… I would never let my own children watch it.” – Zworykin on his feelings about watching television.

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.

The GB-4 guided bomb

GB-4 being dropped from a B-17

RCA engineer showing 1846 iconoscope camera used in bomb

Army officer piloting GB-4 to it’s target

Insides of the camera, iconoscope 1846 outlined in red can be seen at left with deflection yoke and lens

Front view of camera with sketch of 1846 iconoscope tube it used

General view of the camera used in the bomb

Insides the camera – iconoscope can be seen

In 1951 Dr. Vladimir Zworykin married physician, Dr. Katherine Polevitzky. She had recently become a widow of the former mayor of Murmansk, Russia. It was the second marriage for both. Dr. Zworykin had known Katherine at least 20 years before their marriage. In 1933 he and 3 friends, including Loren Jones had purchased an open cockpit biplane and obtained his pilots license. He flew over Taunton Lakes and took aerial photographs for a future lakefront home he had planned. This home was very close to the residence of two other Russian refugees, Katherine and Igor Polevitzky.

Dr. Zworykin, Melbourne, December, 1951

Katherine and Vladimir also visited Australia during this worldwide tour and Dr. Zworykin spoke at Melbourne University on the new Vidicon. They both attended medical lectures as well while on their honeymoon.

Television Monitor showing a Melbourne streetscape, Melbourne, December, 1951

Close up of television monitor showing a Melbourne streetscape, Melbourne, December, 1951

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.

Zworykin received numerous awards related to these inventions, especially television. They included the Institute of Radio Engineers’ Morris Liebmann Memorial prize in 1934; the American Institute of Electrical Engineers’ highest honor in 1952, and the Edison Medal. In 1967 the National Academy of Sciences awarded him the National Medal of Science for his contributions to the instruments of science, engineering, and television and for his stimulation of the application of engineering to medicine.

He was also founder-president of the International Federation for Medical Electronics and Biological Engineering, a recipient of the Faraday Medal from Great Britain (1965) and the U.S. Presidential Medal of Science (1966), and a member of the U.S. National Hall of Fame from 1977.

Zworykin died in Princeton, New Jersey, 29 July 1982.

Iconoscope was the first electronic camera tube

The iconoscope is a type of camera tube that is no longer used, since it is not as sensitive as the image orthicon and its images are subject to uneven shading and flare. But it is well suited to introduce the concepts of electron image storage and scanning in simple form. The iconoscope is housed in a dipper- shaped, vacuum-tight glass envelope. Within the wide end is a flat sheet of mica. A uniform metallic coating, called the signal plate, is placed on the rear surface of this sheet, away from the image. The front surface of the mica is covered with a mosaic composed of many hundreds of thousands of tiny globules of silver.

During the manufacture of the tube the mosaic is treated with cesium vapour and oxygen, so that each globule has a surface of the oxides of silver and cesium. This combination of elements provides a surface from which electrons are readily liberated, by the photoelectric effect, when light falls on it. Since the globules are insulated from each other and from the signal plate by the mica, the loss of electrons under illumination causes the globules to assume and hold a positive charge, the charge on each globule being proportional to the strength of the illumination falling on it and to the time it has been illuminated.

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.

The scanning spot of the iconoscope is formed by a narrow beam of electrons, shot out of an electron gun in the side arm of the tube. On its way to the mosaic, this beam passes within two sets of electromagnet coils. Currents like those of this figure are passed through these coils, causing the beam to be deflected horizontally at a rapid rate and vertically at a relatively slower rate. The extent of the horizontal motion is adjusted from top to bottom of the mosaic, so that the pattern traced out by the electron beam on the mosaic is a rectangular pattern.

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.

One unusual thing about the 1847 is that there is no direct connection between the mosaic and it’s external signal connection. Instead there is a ring of conductive material inside the tube, connected to the mosaic, and a ring of conductive material outside the tube with a signal connection. Thus the signal is picked up through this “capacitor” consisting of two plates, internal and external, with the glass as a dielectric.

RCA 1848 Iconoscope TV Camera Tube ca. 1940.

Selling price in 1948 was $500.00. A similar tube, the 1846, was used in a television guided bomb during the latter part of WW2.

RCA 1850A Image Iconoscope Camera Tube ca. 1950.

One of the earliest commercially available camera tubes. The earlier version, RCA 1850, dates back to 1939. Selling price in 1948 was $540.00. (In 1948 you could buy a house for about $3000).

The 1848 is considerably smaller than the 1850 as can be seen here.

Later versions of the 1850A were painted supposedly to reduce stray light from getting in.

The iconoscope was later replaced but it laid the foundations for early television cameras.

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