A Computer Program for Color Tube Screen Design

A brief review establishes the dependence of the required color phosphor screen geometry on the complete electron-optical system including gun, yoke and other external CRT components. Correction of the light ray paths in optical screen printing requires detailed knowledge of electron beam arrival conditions. The paper describes a technique for mapping three-dimensional yoke field boundaries, calculating the complete internal field, and then precisely determining the beam trajectories and landings. A companion program automatically generates the correcting lens surface which for off-axis beams will be aspheric and asymmetric. A process for manufacturing lenses to this prescription will be indicated.