Electron flow route at phosphor screens in CRTs

The electron flow route at phosphor screen in cathode ray tubes (CRTs) has been discussed. Phosphor screens in CRTs are constructed with loosely packed phosphor particles. Individual phosphor particles are covered with the interface layer and adhered microclusters, which are insulators. Phosphor screen does not form an electric conductance for electron flow. Photoconductive particles are only emitting particles exposed on electron beam. Emitting phosphor particles in the screen do not have an ohmic contact with Al-metal film, of which both the sides are covered with Al2O3 insulator layers. Therefore, Al-metal film on phosphor screen may not collect the electrons from phosphor screen. The electron flow route at phosphor screens in CRT is made with collection of secondary electrons, released from the emitting phosphor particles, by anode. For an efficient collection of the secondary electrons by anode, the anode should be placed under phosphor screens, and phosphor screens should be made with the screen less than two layers of particles.