US 5,200,669 AGranted

Elevated power high-pressure discharge lamp

AssigneePatent-Treuhand-Gesellschaft fur elektrische Gluhlampen mbH

InventorsAngus Dixon, Hans-Werner Goelling, Jorn Dierks, Jurgen Begemann

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Abstract

To prevent stresses from occurring in lamps in which an electrode system luding, for example, tungsten or molybdenum electrode shafts (4, 12, 22) and current supply leads (15, 26) of, for example, molybdenum, extend into a neck portion (3, 11, 20) of a discharge bulb, a metal foil of high temperature resistant resistant material (6, 16, 17, 18, 29, 32, 33, 34, 35, 36, 37) partially or completely surrounds the metallic portions of the electrode system where it might come into contact with quartz glass during melt sealing of the neck portion of the lamp. The high temperature resistant metal foil is embossed and, preferably of molybdenum with a base thickness of between 0.02 and 0.2 mm, which, when profiled, changes by a factor of between 1.2 to 12 in thickness. Up to two layers of this foil can be wrapped around or placed on the respective metallic portions of the seal, a covering of for example, 1.25 to 1.5 turns about a circular shaft being preferred. Adhesion of quartz glass on the current supply elements themselves thus is prevented and tension-free thermal expansion of the electrode shafts and the current supplies is made possible, and, also, providing for better alignment of the electrode systems than possible in accordance with the prior art.

Claims22

Dependent claims

An elevated power high-pressure discharge lamp having

an essentially rotation-symmetrical quartz glass discharge vessel (1, 9, 19) including
a discharge bulb portion (2, 10) defining a discharge space, and
two oppositely extending neck portions (3, 11, 20);
a fill within the discharge space, said fill including at least one ionizable gas or gas mixture and, optionally, at least one of:
mercury;
a metal halide;
two tungsten electrode systems melt-sealed to the discharge vessel, each of said two systems having:
an electrode head (21);
an electrode shaft element (4, 12, 22) supporting the respective electrode head which extends from the discharge space into a respective neck portion (3, 11, 20);
a current supply lead element (15, 26) extending outwardly from the respective neck portion;
at least one molybdenum sealing foil (5, 14, 24) in the respective neck portion (3, 11, 20) electrically connecting the electrode shaft element (4, 12, 22) to the respective current supply lead element (15, 26);
said at least one sealing foil (5, 14, 24) being gas-tightly melt-sealed into the respective neck portion;
and
wherein each of said systems comprises
a metal foil (6, 16, 17, 18, 29, 32, 33, 34, 35, 36, 37) surrounding, at least in part, at least one of:
the electrode shaft element (4, 12, 22);
the current supply lead element (15, 26);
in a region where the at least one electrode shaft element and the current supply lead element is located in the neck portion (3, 11, 20), the metal foil being positioned between the at least one electrode shaft element and the current supply lead element and the material of the neck portion, and
wherein said metal foil comprises a high temperature resistant material defining a metal foil surface, and where the metal foil surface of the metal foil is embossed.

16 more elements

Dependencies are inferred from the claim text.