Glass cathode ray tube - where conical bulb is formed in hot glass tube by an expanding tool

摘要

A monolithic glass neck and bulb for a cathode ray tube is made from a round glass tube which has the cross-section required for the neck. The tube is heated on part of its length, and a tool with expandable jaws is inserted in the hot portion of the tube to make the conical bulb. A front plate carrying a luminescent screen is then attached to the wide end of the bulb by melting or soldering. The tube and the tool are pref. rotated together during forming; and the tool pref. consists of two jaws fitted with mating tongues and grooves so the jaws remain aligned with each other when they are forced apart in a direction parallel with the long front surface of the screen. Provides a new and simple process for mfg. electron tubes which can be undertaken by hand or on a machine.