Low-pressure discharge lamp with a device for switching it off at the end of its service life

US6838813B2 · kind B2 · utility

Assignee

• Patent-Treuhand-Gesellschaft fur elektrische Gluhlampen mbH · DE

Inventors

• Bernhard Blohm · Königsbrunn, DE
• Kirsten Fuchs · Mering, DE
• Achim Hilscher · Friedberg, DE
• Peter Husslein · Coburg, DE
• Gerald Hämmer · Königsbrunn, DE
• Andreas Maciejewski · Weil am Rhein, DE
• Thomas Noll · Kipfenberg, DE
• Klaus Pankratz · Kandern, DE
• Klaus Weingärtner · Augsburg, DE

Key dates

• Filing date: Apr 25, 2003
• Grant date: Jan 4, 2005
• Expiry date: May 4, 2023

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01J61/28
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

The invention relates to a low-pressure discharge lamp, having a tubular discharge vessel made from glass, the free ends of which are closed off in a gas tight manner, two electrode systems (3) each having a filament (7), two supply conductors (5, 6) and a bead (8) of glass, the ends of the supply conductors (5, 6) being fused into the ends of the discharge vessel which have been closed off in a gas tight manner and, in order to be held in a region between the filament (7) and the discharge vessel fused seal (2), into the bead (8), and a device for switching off the lamp at the end of its service life, comprising a paste (9) which contains a metal hydride and is fitted to the bead (8). According to the invention, the bead (8) consists of a glass material which has a resistivity of greater 108 Ωcm at 350° C. Moreover, the paste (9) containing the metal hydride is applied to the bead (8) in the radiation shadow with respect to the thermal radiation which emanates from the filament (7) of the lamp in operation, and is not in electrical contact with the supply conductor wires (5, 6) on the bead (8).