Once in the U.S., Zworykin found work at the
Westinghouse laboratories in
Pittsburgh, where he eventually had an opportunity to engage in television experiments. He summarized the resulting invention in two patent applications. The first, entitled "Television Systems", was filed on December 29, 1923, and was followed by a second application in 1925 of essentially the same content, but with minor changes and the addition of a Paget-type screen for color transmission and reception.
[5] He was awarded a patent for the 1925 application in 1928,
[5]and two patents for the 1923 application that was divided in 1931,
[6][7] although the equipment described was never successfully demonstrated.
[8][9][4]:51,2
Zworykin described cathode ray tubes as both transmitter and receiver. The operation, whose basic thrust was to
prevent the emission of electrons between scansion cycles, was reminiscent of
A. A. Campbell Swinton's proposal published in
Nature in June 1908.
[10][11]