Magnetically deflected CRT electron gun - has magnetic and non-magnetic two=part first accelerating electrode for minimising non-uniform beam focussing

摘要

The electron gun is for magnetically deflected CRT's esp. colour TV tubes. The gun minimises spot defocussing or non-uniform beam focussing which can arise from deviation of the beam away from the lens axis. The gun is bipotential and consists of a mult-electrode electrostatic lens, including a cathode, control and screen grids and two accelerating electrodes. The focussing system lies between these two electrodes. The first accelerating electrode is of two parts, that facing the screen grid being of magnetic material the remaining half being non-magnetic.