| 摘要 |
PURPOSE:To prevent any crack or leak which might be caused in an emission tube during the life performance of a high-pressure metal vapor electric-discharge lamp, and suppress the variation in lamp voltage by appropriately adjusting the thickness of both a tube and an annular body which are components of the emission tube. CONSTITUTION:An emission tube consists of a tube 1 made of alumina, and an annular body 2 which is made of the same material as the tube 1 and is fused to the end of the tube 1. An electrode conductor 3, on the pointed end of which an electrode 5 is provided is attached to the hole of the annular body 2, with a frit 4 interposed between the body 2 and the conductor 3, thereby the emission tube being hermetically sealed. The thickness of the part of the body 2 which is fused to the tube 1 is made approximately the same as that of the tube 1. The thickness of the part of the body 2 which touches the conductor 3 is made larger than that of the fusing part of the body 2. |
