Technikatörténeti szemle 20. (1993)

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

The turning point came almost a year later In May 1931. Again, in Abramson's reconstruction of the events around this time: the Zworykin group at RCA was having very little success with its two-sided camera tubes" and it was decided, around May 14, 1931, „to investigate the single-sided target," that is, the technology which was characteristic for the first iconoscopes. We further learn that according to Zworykin's notebook, „by June 12, 1931, several tubes had been built that were giving quite promising results, and it was decided to proceed along these lines" and that by September or early October „the group at Camden was making excellent progress with the new single-sided camera tube" (43). As the archival files show, In late 1931 Zworykin began to file amendments to his still pending 1923 application, on which there had been no action since 1926. These amendments featured radical revisions, primarily to the important ..claims" (44) section, introducing language associated with storage technology and explaining how the new terminology fitted the originally specified elements and operation. On November 13, 1931, Zworykin filed yet another patent application. A reading of this patent and its archival files reveals that though it describes a device which is ..capable of making visible objects so small as to be otherwise invisible to the eye" (an electron microscope?) the subject of controversy became the television camera it specified, featuring singlesided scanning, mica insulation, platinum collector electrode, and other features characteristic for iconoscopes (45). Thus in August 1934, six claims were denied to this application due to cited prior conception by Tlhanyi and cited publication of his two British patents In 1929 (46). These claims sought to protect priority to single-sided scanning, the adapter tube (the elongated auxiliary tube which makes possible single-sided scanning), and other features associated with the iconoscope. This last effort by Zworykin and RCA to secure the right to the single-sided technology thus defeated, RCA had a camera tube at last, but no control over the rights to the technology. By this time, however, negotiations with Tihanyi had been resumed. Less than three weeks later, according to a September 13, 1934 letter by Tihanyi, an agreement had been signed between himself and RCA. By then, it seems, RCA was manufacturing iconoscopes based on his patents. Namely, as we learn from Abramson, in U.S. Pat. No. 2,047,369, filed in December 1934 by W. Hickok of RCA for a photoelectric device, the inventor stated that the image carrier described in Kalman Tihanyi's copending application „was the type usually constructed" (47).