GB644882A - Improvements in or relating to cathode ray tubes - Google Patents

Abstract

644,882. Glass-to-metal seals. BARASCH, H. P. Sept. 24, 1947, No. 25974. [Class 36] [Also in Group XL (a)] A cathode-ray tube envelope with its end face member assembled in pressure contact with the remainder has thin flexible external sealing means across the pressure contact joint, the flexible sealing means resting against a solid portion of the envelope where it is supported against caving in under external pressure. The end face 1 is a moulded glass blank of uniform thickness and is in polished surface contact with the end of a conical hull 2 of glass or metal, e.g. Cu or Cr.Fe and Ni.Fe alloys, which is integral with or separate from a glass neck 3. Vacuum tightness is ensured by an external ribbon ring 4 which is sealed to projecting parts 5, 6 on the end face 1 and hull 2, respectively. In modifications (not shown), the sealing projections 5, 6 are positioned differently and the ribbon may be corrugated. The metal hull 2 may be joined to neck 3, as shown in Fig. 4, a flexible ribbon diaphragm 10 being welded, brazed, or soldered to the metal hull and sealed to the neck 3. If a metal thimble is used, it is butt sealed to the neck 3. In another modification (not shown), the metal hull rests on a step with an inner support ring, and the flexible ring is in two parts seam-welded together, one end being soldered and the end adjacent the glass end face being sealed in bonding compound, e.g. silver chloride, mixtures of oxides and borates as in glasses and enamels and cements such as silicones. The metal ribbon may be preglassed and the seals obtained by heating in the oven. The hull may be pyramidal.