Color picture tube having an inline electron gun with an astigmatic prefocusing lens

摘要

A color picture tube includes an inline electron gun for generating and directing three inline electron beams along coplanar beam paths toward a screen. The gun includes a plurality of electrodes which form a beam-forming region, a prefocusing lens, and a main focusing lens for the electron beams. The prefocusing lens includes four active surfaces. At least one of the active surfaces has asymmetric prefocusing recesses formed therein.