CATHODE-RAY TUBE

PURPOSE:To improve the emission characteristic of a cathode-ray tube at the application of an electron beam of high density to the fluorescent screen of the tube and heighten the brightness and brightness-life characteristic of the tube by cooling the fluorescent screen of the tube under specific conditions. CONSTITUTION:Temperatures below room temperature can be readily achieved through the absorption of heat by passing currents through dissimilar conductors or semiconductors i.e., the so-called Peltier effect. While a cathode-ray tube is open at room temperature and put in its steady state by actuation of the tube through excitation of high density i.e., a current density of more than 0.1mA/cm per irradiation area and at an accelerating voltage of more than 25kV, the tube is forcibly cooled so that the temperature of the tube surface is more than room temperature and less than 60 deg.C. A cooling effect against the emission characteristic of the cathode-ray tube is thereby heightened so as to heighten the brightness and brightness-life characteristic of the tube.