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US 4,056,752 AGranted
Ceramic lamp having tubular inlead containing yttrium-zirconium mixture
AssigneeGeneral Electric Company
InventorStanley F. Bubar
Life of this patent
Estimating the term…
Abstract
A high pressure sodium vapor lamp arc tube of alumina ceramic has end closures one of which includes an externally projecting tube of niobium or tantalum serving as inlead and having a portion extending into the inside of the arc tube. A tungsten electrode shank is welded into the end of the niobium tube but the seal at the weld may not be fully hermetic. To assure a fully hermetic seal, a mixture of yttrium and zirconium which has a lower melting point than pure yttrium is included in the niobium tube.
Claims5
An electric lamp arc tube comprising:
- a light-transmitting ceramic envelope having end closures sealing its ends and containing a discharge-sustaining filling including a vaporizable metal,
- electrodes supported from said closures at opposite ends of said envelope,
- one of said closures including a tubular niobium or tantalum inlead having a portion extending into the interior of said envelope,
- the electrode supported by said one closure comprising an emitting portion mounted on a tungsten shank,
- said tungsten shank extending from the interiorly extending portion of said inlead and being quasi-hermetically fastened thereto,
- and a mixture of yttrium and zirconium within said inlead at the joint with said tungsten shank, said mixture having been melted in place to form a braze penetrating any pores at the joint in order to assure a hermetic seal between said tungsten shank and said niobium inlead.
3 more elements
An electric lamp arc tube comprising:
- an elongated light-transmitting alumina ceramic envelope having end closures sealing its ends and containing a filling of sodium-mercury amalgam and an inert starting gas,
- electrodes supported from said closures at opposite ends of said envelope,
- a discharge sustaining filling including a vaporizable metal within said envelope,
- one of said closures comprising a metal end cap having an externally projecting niobium or tantalum tube sealed therethrough with a portion extending into the interior of said envelope,
- the electrode supported by said one closure comprising an emitting portion mounted on a tungsten shank,
- said tungsten shank extending from the interiorly extending portion of said tube and the end of said tube being pinched and quasi-hermetically welded about said shank,
- and a mixture of yttrium and zirconium within said tube at the joint with said tungsten shank, said mixture having been melted in place to form a braze penetrating any pores at the joint in order to assure a hermetic seal between said tungsten shank and said tube.
4 more elements
Dependencies are inferred from the claim text.