Development of round glass bulbs for RCA-21CYP22 color picture tubes

This paper describes the development of a round all-glass bulb for use in the RCA 21CYP22 color picture tube. The evolution of this bulb is traced, and various systems used in joining the two-piece bulb are described. These methods included welding of metal flanges, soldering of metal flanges using glass, high-temperature glass sealing, and a new technique, which is described in detail, using a devitrified solder glass. Physical properties of the solder glass are given, and the method used for evaluation of the solder glass and the control tests used to approve material for factory use are outlined.