Electric lamp with pinch sealed outer conductor of non-highly refractory material
AssigneeThorn EMI plc
InventorRoger A. Hume
Life of this patent
Estimating the term…
Loading patent…
AssigneeThorn EMI plc
InventorRoger A. Hume
Estimating the term…
A lead wire arrangement used in the pinch seal of a tungsten halogen incandescent or air burning discharge lamp. The outer lead wires are made of an oxidation resistant material having a melting point significantly lower than the temperature surrounding the foil and lead wire arrangement during the pinch sealing process. Because the temperature reached during pinch sealing is of the order 2,000.degree. C. conventionally outer lead wires have been made of a highly refractory material, for example, molybdenum which has to be coated with platinum to prevent oxidation. The invention uses materials having significantly lower melting points than 2,000.degree. C. which are also oxidation resistant thus avoiding the use of the expensive platinum. Suitable materials for the outer lead wires include titanium wire, titanium coated wire, nickel/iron alloys and titanium/molybdenum alloys.
A lead wire arrangement for sealing in a pinch sealed envelope of an electric lamp, the arrangement including a sealing foil having joined thereto an outer lead wire which is, at least at the surface, made of oxidation resistant material selected from the group consisting of titanium and titanium/molybdenum alloys and having a melting point lower than 2000.degree. C.
In an electric lamp having an envelope closed by a pinch seal arrangement, the pinch seal arrangement comprising a foil seal having attached thereto an outer conductor, the improvement wherein the outer conductor comprises a non highly refractory material selected from the group consisting of titanium and titanium/molybdenum alloys, said non-highly refractory material being also oxidation resistant and having a melting point lower than 2000.degree. C.
Dependencies are inferred from the claim text.