| 摘要 |
PURPOSE:To suppress occurrence of cracking during working under heat, by using such a flare that has a specified radius of curvature at the junction between the flare tube and the flare flange portion. CONSTITUTION:Since the radius of curvature R at the junction between the flare tube 6 and the flare flange portion 9 greatly affects the quality of the lamp after the working under heat, the radius of curvature R in larger-sized flares having more than 35mm. of the diameter of the flare tube 6 and more than 50mm. of the diameter of the flare flange 9 is specified to suffice the following condition defined with the diameter ds of the flare tube 6 and the diameter D of the flare flange 9, namely the radius of curvature R at the junction between the flare tube 6 and the flange portion 9 is specified to be 0.1 ds<=R<=0.1D. Thus, damage such as cracking during the working under heat is prevented and yield in the production process can be increased and the quality can be greatly improved. |
