THE EVOLUTION OF TELEVISION The TV screen at the beginning was the outer surface of a cathode ray tube, coated on the inside with a chemical that produced light by fluorescence upon receiving the impact of a beam of electrons that circulated on the television screen. horizontal mode at high speed producing the image. Later, sizes were reduced with the appearance of the transistor and new electronic circuit technologies. Until flat screens appeared and currently, with the development of optical technologies, liquid crystal, as well as some curved screens for use in video games.