Computer-Aided Design of Color Picture Tubes with a Three-Dimensional Model

Many cathode ray tubes for color television now incorporate non-cylindrical electrodes. The tapered rectangular slot in the beam-forming region [1] , and the overlapping lens [2] for the three beams are typical. The new computer model described here enables the engineer to compare the effects of varied electrode shapes without the expense of building an actual gun. Existing axisymmetric models [3-8] are of only limited use, since an accurate simulation requires the fully three dimensional model to treat angularly varying applied fields and space-charge fields. Here the entire tube is modelled from the cathode to the screen in two or three sections. Experimental and computed spot sizes are in excellent agreement.