Process for forming conductive bridge in cathode ray tubes

Abstract

An improved process for providing positive electrical connection between the shadow mask, the conductive coating and the aluminum film by way of the mask-supporting studs is disclosed. The process is for use in the manufacture of a cathode ray tube having a face panel including a rearwardly extending skirt with a seal land for attachment to a funnel having a mating seal land. The face panel and skirt receive an internal coat of electrically conductive dag. The face panel has an inner surface for receiving a pattern of discrete phosphor deposits overlaid with an electrically conductive aluminum film. The tube includes a shadow mask for color selection receiving a high voltage, and held dependent adjacent to the face panel by a plurality of metal studs extending inwardly from the skirt. The improved process comprises directing a controlled flow of air following the application of the dag coating toward the center of the inner surface of the panel effective to cause a counterflow of air across the skirt to thoroughly dry the dag coating on the skirt. The area of the skirt between the plane of the studs and the skirt seal line is precision-trimmed with acid. The method is such that a permanent electrical connection is maintained between the dag coating and the shadow mask without the need for a separate application of an electrically conductive bridge.