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US 5,404,078 AGranted
High-pressure discharge lamp and method of manufacture
AssigneesPatent-Treuhand-Gesellschaft fur elektrische Gluhlampen mbH, NGK Insulators, Ltd.
InventorsAxel Bunk, Stefan Jungst, Kouichiro Maekawa, Joachim Werner
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Abstract
A high pressure discharge lamp has a ceramic discharge vessel (8), whose s are closed with plugs (11). The metallic feedthrough, or a main part of it, has a thermal coefficient of expansion which is smaller than the coefficient of the ceramic. The current feedthrough is gas-tightly sintered directly into the plug.
Claims29
High-pressure discharge lamp having
- a ceramic discharge vessel (8) defining two open ends;
- an ionizable fill within the vessel;
- two ceramic members, each formed as a plug (11) inserted in a respective open end of the vessel,
- said plugs being formed with an axial opening therethrough;
- a metallic current feedthrough (10) of circular cross-section located in the opening of each plug;
- wherein
- at least a main or first member (16, 16a, 18a, 25a) of the current feedthrough (10) is tubular and has a thermal coefficient of expansion which is smaller than the thermal coefficient of expansion of the ceramic;
- wherein the ceramic discharge vessel (8) consists essentially of alumina;
- the plug (11) is non-conductive and comprises alumina at least as the main component;
- and
- the current feedthrough is gas-tightly sintered into the plug (11) devoid of a ceramic sealing material.
8 more elements
High-pressure discharge lamp as in 16, characterised in that the second member is a rod (25b) which is inserted in the open end (27) of the tubular first member (25a).
Dependencies are inferred from the claim text.