| 摘要 |
A high pressure sodium vapor discharge lamp of the type having a discharge tube with a feed-through tube and an internal electrode at each end of the tube. An outer envelope encompasses the arc tube and there is an arc tube centering means disposed within the outer envelope and electrically coupled to the arc tube. The arc tube centering means is comprised of a geometric configuration which compensates for thermal expansion differences between the arc tube and the outer envelope during lamp sealing and, more importantly, lamp operation. The arc tube centering means includes a pair of offset lead wires, at least one of which has a twisted loop disposed along its length. The offset lead wires are preferably made of niobium.
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