Hybrid implosion protection system for a flangeless faceplate color cathode ray tube and method of assembly thereof

A color television picture tube having a glass bulb including an approximately rectangular, flangeless, three-dimensionally curved faceplate having a convex front surface, a concave rear surface and an edge surface which, along the sides of the faceplate, arches away from a reference plane connecting the four corners of the facelate, the glass bulb also having a funnel with a convex seal land which mates with the concave inner surface of the faceplate, said tube having a hybrid implosion protection system comprising:

• a high tensile strength frame which surrounds and is closely spaced from and a marginal portion of said funnel adjacent said faceplate to define a cavity between the frame and the bulb, said frame having a radially outwardly extending bracket at each corner thereof;
• a hardened cement in said cavity between said frame and said faceplate, said frame and said cement binding up said edge surface of said faceplate, said marginal portion of said funnel, and the faceplate-funnel interface to provide a measure of implosion protection;
• and
• a tension band disposed over said frame and the hardened cement in said cavity so as to surround said faceplate in straight lines between the faceplate corners, said tension member being retained on the faceplate corners by said brackets, said band being under tension to produce radially inwardly directed force components acting on the faceplate corners through the frame and hardened cement, the combination of said cemented frame and tension member producing a high degree of implosion protection for the bulb.

For use in the manufacture of a color television picutre tube having a glass bulb including an approximately rectangular, flangeless, three-dimensionally curved faceplate having a convex front surface, a concave rear surface and an edge surface which, along the sides of the faceplate, arches away from a reference plate connecting the four corners of the faceplate, the glass bulb also having a funnel with a convex seal land which mates with the concave inner surface of the faceplate, a method of assembling on the tube a hybrid implosion protection system comprising:

• surrounding in close adjacency at least the edge surface of said faceplate with a high tensile strength frame so as to define a cavity between the frame and the faceplate edge surface;
• introducing a cement into the cavity between the frame and the faceplate;
• effectuating a hardening of the cement such that the frame and the cement bind up the edge surface of the faceplate to provide a measure of implosion protection;
• and
• after said cement is hardened, placing a tension member over said frame so as to surround the faceplate in straight lines between the faceplate corners, and then tensing the tension member to produce radially inwardly directed force components on the faceplate corners through the frame and hardened cement, the combination of the cemented frame and tension member producing a high degree of implosion protection for the bulb.