| 摘要 |
PURPOSE:To improve mechanical strength by jointly fixing the opening ends of two U-shaped inner tubes, which are arranged inside an outer tube in a bulb-shaped low pressure mercury vapor discharge lamp so as to define a dis charge path, to the outer tube base part with an inorganic adhesive or the like. CONSTITUTION:Inside a gastight space formed of an outer tube 1 and the outer tube base part 2, two U-shaped inner tubes 3, whose one end each is fixed to the base part 2 while sealing an electrode inside 4 while the other end is made into an opening 5, are arranged for forming a bulb-shaped low pressure discharge lamp. Thereby, the inner tube opening parts 5 and the outer tube base part 2 are jointly fixed at the glass welding part 9 by using a supporting rod 8 of glass, ceramics and a metal, or are fixed by glass welding while providing the inner tube extention parts. Accordingly, the inner tubes 3 are fixed to the outer tube base part 2 on both ends so as to be able to heighten reliability against vibration and impact by increasing mechanical strength. |
