Spatial Relationship of Convergence Components with Spot Size

The relationship between spot size and magnetic correction of the electron beams for convergence and purity is described for color picture tubes. It is shown how this correction can impair picture resolution in modern electron guns. An optimum arrangement of correction magnets is presented which improves resolution while maintaining convergence and purity functions. Actual receiver tests indicate a 35% improvement in resolution using the same corrective magnets in the optimum positions. This improvement will enable small diameter electron guns as well as einzel focus electron guns to be used in color television receivers.