| 摘要 |
PURPOSE:To surely maintain air-tightness throughout a long time, by improving security strength between a glass tube and stem in an electric discharge lamp in which the stem is sealed to an end part of the glass tube by a frit to internally form an air-tight space. CONSTITUTION:A U-shaped recessed groove 33 integrally formed in the peripheral edge of a stem 3 corresponding to a shape in the end part of a glass tube 1, under a condition fitted with the tube 1, is provided with a width having capable size of forming gaps S between both sides 13, 14 of the tube 1 and a wall face of the groove 33. Then the tube 1 is secured to the groove 33 under a condition filled with a frit 4 in the gap S formed by the both sides 13, 14, end face 12 and the wall face of the groove 33. Here height H of the wire 4 from the end face 12 of the glass tube is equally formed in both of the sides 13, 14. In this constitution, an outflow of the frit 4 is suppressed and the frit 4 can be interposed also in the part of the both sides 13, 14 in addition to the end face 12 of the glass tube. |
