| 摘要 |
PURPOSE:To prevent any breakage of the fine tube and reliably prevent an amalgam from dropping by installing a member for preventing the dropping of the amalgam between the amalgam and the opening of the fine tube and providing said member with a ventilation path. CONSTITUTION:A nickel sleeve 11 used as a member for preventing an amalgam 16 from dropping, is charged in an exhaust tube 8. The sleeve 11 has a small- diameter section 13 which is located on the side of the fusing area of the exhaust tube 8. In order to prevent the sleeve 11 from moving inside the exhaust tube 8, the sleeve 11 also has a node 15 connected to the node 14 of the exhaust tube 8. In the space formed between the pointed end of the exhaust tube 8 and the sleeve 11, the amalgam 16 is charged which controls the mercury vapor pressure of the internal space of the bulb 1 during lighting. The sleeve 11 has a cylindrical shape and therefore works as a ventilation path 11a for exhausting the bulb 1. It also works as a path for the stream of mercury produced during lighting. |
