Technikatörténeti szemle 20. (1993)

TANULMÁNYOK - Tihanyi Glass, Katalin: The Iconoscope: Kalman Tihanyi and the Development of Modern Television

with the People's Almanac being just about the only publication which continues to list the iconoscope as a 1923 Zworykin invention. Thus, depending on the source, we may learn that the year when Zworykin invented...or ..developed" ...or ..constructed" the iconoscope was 1928 (Smithsonion Institution), 1931 (Encyclopedia Americana, A. Abramson, F. Lovece, P. Farnsworth), 1933 (Los Angeles Times), and 1938 (Isaac Asimov). It Is currently acknowledged that the first Zworykin applications which show storage-related technology date from 1930, and that the application showing specific characteristics of the iconoscope was filed in 1931, five years after Tihanyi's 1926 application and three years after Tlhanyl's 1928 applications describing further refined versions of storage technology. Early electronic television As is well known, television is transmitted by ..scanning" a screen, also called „image carrier" or ..target," upon which the image is projected. This scanning is accomplished by the cathode ray which explores the screen point by point and line by line. The method of transmitting pictures by breaking them down into elemental areas and reassembling the electrical impulses representing these individual points at the receiving side, had been suggested by the German inventor Paul Nipkow in 1884 (21). Although Nipkow's was a mechanical device, the idea of scanning has never been replaced by a better one. The idea for the image carrier itself, a device which would use the human eye as a model, was first suggested by Aryton and Perry in 1877. They published their plan in 1880, proposing to build a large mechanical eye with selenium cells as the retina. But, as with all ..seeing," whether the medium is the retina of the eye, a photographic plate, or a television target, of crucial consequence for ..picture definition" is the medium itself and the time it Is exposed to the light from the Image. Of this logically follows that the television camera, and within it its target, in effect its „eye," is the most important element for good television transmission. The task of creating a device which would accomplish ..seeing" at distances the human eye could not span proved to be a formidable challenge. To illustrate the difficulty of what had to be accomplished in order to make viable television transmitting devices, let us quote verbatim the first of two letters, published in Nature on June 18, 1908, by A. A. Campbell