摘要 |
PURPOSE:To uniform distances from the center axis and the top of an electrode to the quartz glass enclosure by sealing the both ends of the quartz glass enclosure after fixing the electrode body in position through welding the quartz glass to the protrusion formed by folding a part of the seal foil of the electrode body. CONSTITUTION:An electrode body is formed by the following steps: a protrusion 20 is formed by folding a cut line portion 18 of a seal foil 19, the portion of the seal foil 19 existing inward of the folded portion is welded to one end of an electrode 3, and a lead rod 7 is welded to the other end of the seal foil 19. Under the state of a quartz glass enclosure 1 being stationary, a part of the quartz glass enclosure 1 around the protrusion 20 formed by folding of the seal foil 19 and a part of a tube side 9 are heat-melted and the quartz glass is welded to the protrusion 20; thus the electrode body is fixed. After that, while rotating the quartz glass enclosure 1, the seal foil 19, the end of the electrode 3, and the tube side 9 around the lead rod 7 are heat-melted and sealed. |