Kálmán Tihanyi

Kálmán Tihanyi as a scientist of British Air Ministry. Tihanyi worked on television-guidance for defense, building prototypes of his robot (optically controlled pilotless) aircraft in London for the British Air Ministry

Kálmán Tihanyi (April 28, Üzbég, Kingdom of Hungary 1897 - February 26, 1947 Budapest), was a Hungarian physicist, electrical engineer and inventor. A pioneer of electronic television, he made significant contributions to the development of Cathode Ray Tubes (CRTs) which were bought and further developed by the Radio Corporation of America (later RCA),^[1][2] and German companies Loewe and Fernseh AG.^{[citation needed]}

Career

Drawing from Tihanyi's 1926 patent application Radioskop. The application included design of a fully electronic display and camera tube, and is part of UNESCO's Memory of the World archive.^[3]

From European Patent Office abstract of Tihanyi's 1928 application Improvements in television apparatus^[4]

Born in Üzbég, Hungary, now Zbehy, Slovakia, Tihanyi studied electrical engineering and physics in Pozsony (today Bratislava)^{[note 1]} and Budapest.^{[citation needed]}

During World War I, Tihanyi served as artillery engineer, then as radio engineer at the Austro-Hungarian Navy Headquarters in Pola, where his remote controlled submarine mine was developed and successfully used. It was subsequently honored as an outstanding military invention. Though his preoccupation with the problem of television goes back to at least 1917, it was not until 1924 that Tihanyi found the solution he was looking for and began conducting experiments.^[5] By April 1925, he had confirmed the soundness of his plans, and on March 20, 1926, applied for his first television patent.^[6][7]

Tihanyi called his fully-electronic television system "Radioskop", and his application contained 42 pages detailing its design and mass production.^[3] Though it bears certain similarities to earlier proposals employing a cathode ray tube (CRT) for both transmitter and receiver, Tihanyi's system represented a radical departure. Like the final, improved version Tihanyi would patent in 1928, it embodied an entirely new concept in design and operation, building upon a technology that would become known as the "storage principle". This technology involves the maintenance of photoemission from the light-sensitive layer of the detector tube between scans. By this means, accumulation of charges would take place and the "latent electric picture" would be stored. Tihanyi filed two separate patent applications in 1928 then extended patent protection beyond Germany,^[8][9] filing in France,^[10] England,^[11][12] the United States, and elsewhere.

In 1928, Tihanyi went to Berlin, where the development of mechanical television involving Nipkow disks had already been begun by the German Post Office and the larger manufacturers. The invention was received with enthusiasm by Telefunken and Siemens, but in the end they opted to continue with the development of mechanical television.^[13]

From 1929, Tihanyi worked on television guidance for defense applications, building prototypes of a camera for remotely guided aircraft in London for the British Air Ministry, and later adapting it for the Italian Navy.^[13][14] In 1929, he invented the first infrared-sensitive (night vision) electronic television camera for anti-aircraft defense.^[15][16]

RCA approached Tihanyi in 1930, after the publication of his patents in England and France. Negotiations continued until 1934, when RCA, ready to unveil its new television system which employed Tihanyi's storage principle, purchased his patents. These covered controlling features that the U.S. Patent Office patent examiners, citing Tihanyi's prior publications, had denied several key patent claims to Zworykin's pending applications from 1930 and 1931.^{[citation needed]} Tihanyi's U.S. patents for his display and camera tubes, assigned to RCA, were issued in 1938 and 1939, respectively.^[1][2]

Drawing of Tihanyi's design for a flat-panel television system, 1936^[17]

In 1935 through 1940, Tihanyi completed plans for an Acoustic Radiator with a planned projection range of up to 8 km, and in 1940 returned to Hungary where he built a full-scale prototype of the device.^{[citation needed]}

In 1936 Tihanyi described the principle of "plasma television" and conceived the first flat-panel television system.^[18][17]

Following Hungary's March 19, 1944 occupation by Germany, Tihanyi (as "friend of America") was arrested by the Gestapo and imprisoned at the Margit Boulevard prison. Although he survived five months of solitary confinement, starvation and interrogations, following the failed attempt at armistice on October 15 by Regent Miklós Horthy and the installation of the Szálasi government, like the rest of the Resistance, he went underground.^{[citation needed]}

At his death, he left behind a large number of inventions. Those he deemed most valuable were almost without exception conceived between 1935 and 1940. These included a sound abatement device and sound abatement wall, energy-saving light bulbs, a device for the separation of infrared waves from light waves, magnetostrictive telephone, sonar detector, and a cluster of other inventions based on ultrasound technology, among them a device for the elimination of carbon monoxide emissions. These manuscripts were marked: "To be saved for peacetime".^[19]

Charge-Storage: a new physical phenomenon

In an internet article, The Iconoscope: Kalman Tihanyi and the Development of Modern Television, Tihanyi's daughter Katalin Tihanyi Glass notes that her father found the "storage principle" included a "new physical phenomenon", the photoconductive effect:

The earliest reference to the new phenomenon this writer found is in an article, entitled "About the Electrical Television," written by Kalman Tihanyi and published on May 3, 1925, nearly one year prior to his first application for patent on an all-electronic television system. Although the inventor does not use the term "storage principle" of "storage effect," the description of the new phenomenon he had discovered implies that that is exactly what he had in mind. Thus, he wrote:

"The writer of this article has studied thoroughly all phenomena known from the current state of the physical sciences which could be applied to the solution of the problem and on the basis of control calculations found them unfit for the achievement of the minimally required 1/80,000 s efficiency at the transmitting station. However, during experimentation a new physical phenomenon was discovered, under which the optical and the electrical effect is practically simultaneous. In fact displacement between the two effects could not be detected with our instruments, although the possibility exists for a displacement of 1/400,000,000 of a second based on Maxwell's equations in regard to a related phenomenon. This means that under this phenomenon not only the desirable 1/150,000 second changes, but 1/400 million changes can be followed" (K. Tihanyi: "Az elektromos távolbavetítésről" ("About electric transmission"), Nemzeti Újság, May 3, 1925, p. 23). (Emphasis added.)

An investigation of various dictionaries and lexicons confirms that, indeed, in addition to the photoelectric (or photoemissive) effect, storage television technology also involves an entirely different phenomenon.

Evident from these characterizations is that while under the photoelectric effect bound electrons released from such photosensitive materials vary linearly with the frequency of the radiation, "that is for each incident photon an electron is ejected," under the storage effect a photoconductive and photovoltaic phenomenon occurs where ("apart from the liberation of electrons from metals") when photons are absorbed in a p-n junction (in a semiconductor) or metal-semiconductor junction, "new free charge carriers are produced," (photoconductive effect) and where "the electric field in the junction region causes the new charge carriers to move, creating a flow of current in an external circuit without the need for a battery," (photovoltaic effect) (The International Dictionary of Physics and Electronics, N.Y. 1956, 1961, pp. 126, 183, 859-861, 863, 1028-1028, 1094-1095).

The Concise Dictionary of Physics under the heading, "Photoelectric Cells," differentiates between "the original photocells" (which utilized photoemission form a photosensitive surface and their attraction by the anode) and "the more modern photocells which utilize the photoconductive and photovoltaic effect" (The Concise Dictionary of Physics, Oxford, 1985).^[20]

See also

• History of television

References

6. "Radioskop", filed March 2o, 1926. File No. T-3768, Patent Office Documents, Hungarian National Archives.

Notes

1. ^ The city was named Bratislava only in 1919.

External links

• Forward to start at www.mtesz.hu
• Kálmán Tihanyi
• http://www.unesco.org/webworld/mdm
• http://www.iec.ch/100years/techline
• Ungarisches Staatsarchiv at www.mol.gov.hu