In order to be able to transmit an image over a long distance, you need to convert an optical signal in electric. Such a transformation is based on a phenomenon called a photoeffect. Discovered this phenomenon (true, failing to explain it, since then there was no concept of “electron”) by German physicist Herz in the late 19th century.
Russian physicist Stoletov in February 1888 conducted an original experience confirming Hertz’s conclusions. Stoletov called this phenomenon an “actino-electric discharge”. And soon after, the famous physicist Thomson introduced the concept of “electron” and convincingly substantiated the electronic nature of the photoeffect.
In the early 20th century, physicists and engineers pondered the issue of practical application of the photoeffect. Including, they began to consider the possibility of transmitting a light image by transforming it into a sequence of electrical signals. However, it was only the first stage to address this transformation. It was still necessary to transmit these signals over a long distance, as well as to create a receiving device in which the reverse conversion of electrical signals into a light image would be carried out. If radio transmitters, which had reached a high technical level, were ideal for transmitting signals, it was difficult to create a receiving device.
A number of interesting optical-mechanical designs of such devices have been proposed, of which the so-called “Nipkov disk” was the greatest distribution “. However, the true heyday of television began after the creation of electron-beam tube (CRT) televisions. The electron-beam tube was invented as early as 1897 by the German physicist Braun, and was the first to suggest its suitability for television imaging by the Russian physicist Rosing in 1907. The original CRT design was proposed in 1930 by Soviet physicist Konstantinov. Although it found no practical application, but served as a starting point for further works. In the USSR, the first TV KVN-49 with a screen size of only 145×100 mm was created in 1949. Now when looking at it you can only smile, and then it was considered a miracle of technology.