| 摘要 |
PROBLEM TO BE SOLVED: To reduce the stress and strain generated in a sealed part and to reduce the axial deviation of electrodes by using metal cylindrical bodies for the sealing parts of a lamp for the large current formed by arranging a plurality of sealing metal foils and by specifying the relation between the length of the sealing metal foils and the thicknesses of the metal cylindrical bodies. SOLUTION: Glass quartz 3 is interposed between an electrode core bar 1 and a sealing tube 2 so as to hold the electrode core bar 1. Four sealing metal foils 4 are connected planarly symmetric to each other by welded to short-side surfaces of the inner metal cylindrical body and an outer metal cylindrical body 6. An air-tight sealing glass quartz body 7 is arranged inside the sealing metal foils 4. When the length of the sealing metal foils 4, the thickness of the inner metal cylindrical body 5, and the thickness of the outer metal cylindrical body 6 are set to L (mm), T1, and T2 respectively and if the relations 2<=T1<=1/6 and 2<=T2<=1/6 with the welding tab 2 mm included therein are satisfied, the stress and the deformation of the sealing part can be prevented.
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