| 摘要 |
672,672. Glass-to-metal seals. PHILIPS ELECTRICAL INDUSTRIES, Ltd. Sept. 7, 1950 [Sept. 10, 1949], No. 22058/50. Drawings to Specification. Class 36. [Also in Group XL (a)] Sealing of the glass window of a cathode-ray tube to the open end of a metallic conical envelope is effected by placing the window on top of the cone when inverted and progressively heating the cone by a high-frequency coil surrounding it and slowly raised to the wide end of the cone so that the glass is uniformly heated by radiation from the cone and by heat radiated or reflected from a metal or insulating screen surmounting it, sealing of the glass to the cone taking place when the coil reaches the top edge of the cone. Alternatively the cone may be lowered through the coil. The upper side of the screen may be reflecting to reduce radiation, may be heated by a burner and rotated, and may be slotted to avoid induced heating by the coil. The cone is held in a holder and may be open at the base and receive a plug admitting an inert gas under pressure into the cone to keep the window floating at its molten edge. The coil may. be gradually lowered after sealing to allow cooling, or the tube uniformly cooled down in a furnace. A glass tube carrying the electrode assembly is finally sealed to the narrow end of the cone. |
