Cathode-ray and other vacuumized tubes resistant to fracture and capable of controlled devacuation

Claim 1

AN ESSENTIALLY ALL-GLASS CATHODE-RAY TUBE ENVELOPE RESISTANT TO FRACTURE COMPRISING A SUBSTANTIALLY FUNNEL-SHAPED HOLLOW BODY PORTION HAVING A VIEWING PORTION ENCLOSING ITS LARGER FORWARD END AND A NECK TUBULATION PROJECTING FROM ITS SMALLER REARWARD END, AND REINFORCING MEANS EXTERIORLY SURROUNDING THE PERIPHERAL SIDEWALL REGION OF SAID VIEWING PORTION HAVING SUFFICIENT YIELD STRENGTH TO PREVENT FRACTURE PROPAGATION THROUGH THE SIDEWALL THEREBENEATH ON BREAKAGE, SAID REINFORCING MEANS INCLUDING AT LEAST ONE ANNULAR BAND SUBSTANTIALLY PLANAR IN TRANSVERSE CROSSSECTION HAVING ITS FORWARDMOST LEADING EDGE DISPOSED ADJACENT AND FOLLOWING THE NON-VIEWING PERIPHERAL CONTOUR OF SAID VIEWING PORTION AND ITS TRAILING EDGE EXTENDING REARWARDLY THEREFROM, SAID ANNULAR BAND IN THE AREA OF SAID LEADING EDGE BEING SPACED FROM SAID SIDEWALL AND COOPERATING THEREWITH TO DEFINE AN ANNULAR GAP AND IN THE AREA OF SAID TRAILING EDGE BEING COMPLEMENTALLY CONTOURED TO RESIDE IN INTERFACIAL CONTACT WITH THE EXTERIOR SURFACE OF SAID SIDEWALL.