In 1908, the English engineer Alan Archibald Campbell-Swinton[en] proposed to scan the image in the transmission tube using an electron beam. In 1911 he developed a scheme of electronic TV and described it in detail in the June issue of the journal “Nature”. The author did not carry out practical implementation of this TB system and its patenting.
In the early twenties of the last century, the Ukrainian inventor Borys Grabovsky developed, designed and in 1923 manufactured an electronic transmitting tube “Electronic switch”. During 1924 – 1925, B. Grabovsky in co-authorship with his associates N. Piskunov and V. Popov developed a scheme and on November 9, 1925 filed documents for patenting of electronic TV. Patent № 5592 was received on June 30, 1928. In early 1928, B. Grabovsky and his assistant Ivan Bilyansky mounted and adjusted electronic TV called “Radiotelephone”. The first picture transmitted to the next room at a distance of 7 meters was a moving image of the hand of B. Grabovsky’s wife, who helped in conducting experiments.
On July 26 and August 4, 1928, in Tashkent, a public demonstration of TV and acceptance by the scientific commission of the local university took place. On the green screen of the receiving CRT with a diameter of 20 cm, pedestrians were observed, a tram crossing the square and the face of a man in which everyone recognized I. Bilyansky, who took off and put on a hat, turned his head, spoke (silently). The image was stable and clear, but black and white stripes were superimposed on it from time to time as a result of spark interference from electric and motor vehicles. The video session was recorded by newsreel. Wireless transmission of moving images was carried out at a distance of tens of meters.
In December 1923, the American engineer, inventor Vladimir Zvorykin developed a scheme of electronic TV using electronic transmitting and receiving tubes and applied for a patent, but received it only in 1938 (US 2022450), after proving the operability of the scheme. In 1925 V. Zvorykin demonstrated the transmission of a rather blurred, motionless image of lines. History is silent about what kind of TV was demonstrated: semi-electronic or electronic TV (incomplete) with such inertial components that its characteristics were worse than those developed by B. Rozing in his time. It is only known that after demonstrating the TV to the management of Westinghouse, where V. Zvorykin worked, he was “advised” to do more useful things.
On November 16, 1929, Zvorykin, who at that time was already working at RCA, applied for and received US patent No. 2109245 for a CRT, the so-called kinescope. Demonstration of electronic TV with moving image took place on November 18, 1929. It was a 120-line system of electronic television with a speed of 24 frames per second, with a new tube – kinescope.
In 1925 at the transport exhibition in Munich, German scientist M. Dickmann demonstrated a television system with electronic transmitting and receiving tubes. In the transmitting device, a 50-line image transformation was carried out. Still images of transport highways schemes were transmitted. The TV system was capable of transmitting moving images of silhouettes. On October 3, 1927, the patent DE450187 (C) with priority from April 5, 1925 was received for the transmitting cathode ray tube.
In 1926, Hungarian engineer Kalman Tihany developed a scheme and patented a TV system. He proposed a tube with charge accumulation for transmission.
On September 7, 1927, American scientist Philo Farnsworth transmitted still images (straight line and triangle) between two laboratories. In this TV system, along with electronic tubes, electromechanical elements were also used. Investors wanted to see the image of “at least one of the spent dollars”. After some time F. Farnsworth sent the image of the dollar.
Only by the autumn of 1928 he managed to avoid the use of electromechanical elements and held a public demonstration of electronic TV on September 1, 1928. The patent was received on September 26, 1930 with priority from January 7, 1927. To transmit moving images, the author used a tube of his own design, called a dissector. The reception was carried out by an electronic tube with a square inch blue screen, with a frequency of 20 frames per second. Patents related to the development of the dissector were bought for 1 million dollars by the company “RCA” in which V. Zvorykin worked. However, it is claimed that only in 1929 F. Farnsworth’s television system was improved by eliminating the motor generator, after which it no longer had mechanical parts.
