Method for the thermal treatment of tungsten electrodes free from thorium oxide for high-pressure discharge lamps
AssigneeKoninklijke Philips Electronics N.V.
InventorsGerhard Hebbinghaus, Jozef Merx
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Abstract
The invention relates to a method for the thermal treatment of tungsten electrodes having a fibrous mocrostructure and being free from thorium oxide for high-pressure discharge lamps, to such a tungsten electrode free from thorium oxide, to a method of manufacturing a high-pressure gas discharge lamp with at least one such tungsten electrode free from thorium oxide, to a high-pressure gas discharge lamp with at least one such tungsten electrode free from thorium oxide, and to a lighting unit with at least one such high-pressure gas discharge lamp.
Claims11
A method for the thermal treatment of tungsten electrodes free from thorium oxide for high-pressure discharge lamps, characterized in that the tungsten electrodes consist of pure tungsten or of tungsten doped with at least potassium, wherein said electrodes have a fibrous microstructure, and the maximum temperature during the thermal treatment is lower than the recrystallization temperature of the material of the tungsten electrodes;
- wherein the thermal treatment yields a cleaning of the electrode surface.
A method for the thermal treatment of tungsten electrodes free from thorium oxide for high-pressure discharge lamps, characterized in that the tungsten electrodes consist of pure tungsten or of tungsten doped with at least potassium, wherein said electrodes have a fibrous microstructure, and the maximum temperature during the thermal treatment is lower than the recrystallization temperature of the material of the tungsten electrodes;
- and,
- wherein the fibrous microstructure remains intact until first operation.
Dependencies are inferred from the claim text.