Display technology: from LCD to QLED The purpose of this thesis is to show the characteristics and validity of LCD Technology by reconstructing the diachronic process that brought the production systems from primitive and cathodic TV to the latest Led Technology, passing from the “traditional” LCD market. The work is divided into three chapters, respectively, of LCD technology, OLED technology, and QLED technology. The starting point was 1907 when Boris Rosing, a lecturer at the technical institute in St. Petersburg, demonstrated a primitive TV system that employed the cathode ray tube, or CRT (Cathode Ray Tube) accompanied by electromagnetic deflection. The main problem for the cathode ray tube was to obtain a “vacuum” pushed inside the tube itself.