| 摘要 |
PURPOSE:To suppress exfoliation of a frit and surely maintain air-tightness throughout a long time, by improving security strength between a glass tube and stem. CONSTITUTION:In construction where a glass tube is air-tightly secured to the peripheral edge of a metallic plate stem, a glass tube receiver part 9 is folded at a right angle from the peripheral edge part of a metallic plate stem 3, composed of 11-14% chrome and the rest iron, correspondingly to an internal diameter of a glass tube 1 to present a hook shape having a U-shaped curved part 91 in the point end part. That is, the part 9 is formed in such a manner that height of one side part 92 to be a free end of the part 9 is lower than the other side part 93 successively provided to a stem base level 31. Then a frit 4 is filled in the periphery of a glass tube end part 11 fitted to the part 91 in the part 9. Thus a distance H from a glass tube end face 12 to the level 31 is formed larger than a distance (h) from the face 12 to the upper face of the frit 4. |
