| 摘要 |
A high-pressure discharge lamp is effective to prevent initial blackening on an outer casing thereof, is of a long service life, and can easily be manufactured. A tungsten wire is wound as a double coiled winding around an electrode metal rod, leaving a tip end thereof, and the double coiled winding is machined into a melted tip end by a YAG laser beam, with the remaining double coiled winding used as a coil. The left tip end of the metal rod is machined into a nipple on the distal end of the melted tip end. If it is assumed that the melted tip end has a diameter D1 and a length L1 up to its distal end, the nipple has a proximal end having a diameter D2 and a length L2 from the proximal end up to the distal end thereof, and the coil and the melted tip end (including the nipple) have a volume V1 and the melted tip end (including the nipple) has a volume V2, then the electrode assembly is machined to satisfy at least one of the conditions 0.15 </= D2/D1 </= 0.3, 0.2 </= L2/L1 </= 0.4, and 0.2 </= V2/V1 </= 0.4. The machined electrode assembly is incorporated as an electrode into a lamp bulb. <IMAGE> |
