| 摘要 |
PURPOSE: To prevent the generation of the crack of a glass member and an internal lead bar holding cylinder body, and lengthen the service life by arranging metallic foil thinner than a metallic plate between the glass member and the metallic plate. CONSTITUTION: In a heat treatment process of a sealing tube part 81, a glass member 1 and a metallic member 3 different in an expansion coefficient are isolated from each other by high melting point metallic foil M having a thickness of 30μm. Therefore, the members 1 and 3 are not welded together. In the metallic foil M, a thickness is set in 30μm, and in a metallic plate 3, since a thickness is set in 0.5mm in order to support an internal lead bar 4 and an electrode 9, the metallic foil M is extremely thinner than the metallic plate 3, and even if the member 1 is melted and contacts with the metallic foil M in a heating and cooling process of the sealing tube part 81, expansive force and contractive force applied to the member 1 by the metallic foil M is extremely small. Therefore, the generation of a crack of the member 1 can be prevented.
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