METHOD FOR MANUFACTURING ULTRAVIOLET RAY DISCHARGE TUBE

• Main Authors: MATSUDA YUKI, KATAGIRI MUNEKAZU, TSUMURA YOSHIHIRO
• Format: Patent
• Language: English; Japanese
• Published: 22.06.2015
• Subjects: BASIC ELECTRIC ELEMENTS; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS; ELECTRICITY; MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR; PERFORMING OPERATIONS; SOLDERING OR UNSOLDERING; TRANSPORTING; WELDING; WORKING BY LASER BEAM

PROBLEM TO BE SOLVED: To provide a method for manufacturing a UV tube, capable of preventing a surface of a cathode electrode from being contaminated during a laser welding process, and also capable of preventing occurrence of cracks.SOLUTION: In a process for irradiating a surface 20 of a plate-like cathode electrode 14 with a laser beam 21 to weld one end parts of kovar wires 16a-16c in contact with a rear surface 19, the surface 20 is disposed at a position shifted from a focused portion 23 of the laser beam 21 in an optical axis direction. Thus, an energy density of the laser beam 21 on the surface 20 is decreased, and thereby recrystallization of tungsten constituting the cathode electrode 14 is suppressed. 【課題】レーザー溶接の工程においてカソード電極の表面の汚染を防ぎ、かつクラックの発生を防ぐことができるＵＶチューブの製造方法を提供する。【解決手段】板状のカソード電極１４の表面２０にレーザー光２１を照射して、裏面１９に当接したコバール線１６ａ〜１６ｃの一端部を溶接する工程において、レーザー光２１の焦点部２３から光軸方向にずらした位置に表面２０を配置する。これにより、表面２０におけるレーザー光２１のエネルギー密度を低下させて、カソード電極１４を構成するタングステンの再結晶を抑制する。【選択図】図１