EP1548788B1 - Elektrode system for discharge lamp, discharge lamp comprising such electrode system and method of fabrication of such an electrode system - Google Patents

Elektrode system for discharge lamp, discharge lamp comprising such electrode system and method of fabrication of such an electrode system Download PDF

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Publication number
EP1548788B1
EP1548788B1 EP04028991A EP04028991A EP1548788B1 EP 1548788 B1 EP1548788 B1 EP 1548788B1 EP 04028991 A EP04028991 A EP 04028991A EP 04028991 A EP04028991 A EP 04028991A EP 1548788 B1 EP1548788 B1 EP 1548788B1
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EP
European Patent Office
Prior art keywords
electrode
metal foil
power supply
supply wire
electrode system
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Not-in-force
Application number
EP04028991A
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German (de)
French (fr)
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EP1548788A3 (en
EP1548788A2 (en
Inventor
Thomas Bittmann
Bodo Mittler
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Osram GmbH
Original Assignee
Patent Treuhand Gesellschaft fuer Elektrische Gluehlampen mbH
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Publication date
Priority claimed from DE10361105A external-priority patent/DE10361105A1/en
Priority claimed from DE200410003041 external-priority patent/DE102004003041A1/en
Application filed by Patent Treuhand Gesellschaft fuer Elektrische Gluehlampen mbH filed Critical Patent Treuhand Gesellschaft fuer Elektrische Gluehlampen mbH
Publication of EP1548788A2 publication Critical patent/EP1548788A2/en
Publication of EP1548788A3 publication Critical patent/EP1548788A3/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J5/00—Details relating to vessels or to leading-in conductors common to two or more basic types of discharge tubes or lamps
    • H01J5/32—Seals for leading-in conductors
    • H01J5/38—Pinched-stem or analogous seals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/02—Details
    • H01J61/36—Seals between parts of vessels; Seals for leading-in conductors; Leading-in conductors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/24—Manufacture or joining of vessels, leading-in conductors or bases
    • H01J9/28—Manufacture of leading-in conductors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/24—Manufacture or joining of vessels, leading-in conductors or bases
    • H01J9/32—Sealing leading-in conductors
    • H01J9/323—Sealing leading-in conductors into a discharge lamp or a gas-filled discharge device
    • H01J9/326—Sealing leading-in conductors into a discharge lamp or a gas-filled discharge device making pinched-stem or analogous seals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01K—ELECTRIC INCANDESCENT LAMPS
    • H01K1/00—Details
    • H01K1/38—Seals for leading-in conductors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01K—ELECTRIC INCANDESCENT LAMPS
    • H01K1/00—Details
    • H01K1/40—Leading-in conductors

Definitions

  • the invention relates to an electrode system for a discharge lamp according to the preamble of patent claim 1 and to a discharge lamp with such an electrode system and to a method for producing such an electrode system.
  • Such an electrode system is for example in the European patent application EP 0 884 763 A2 disclosed.
  • This document describes an electrode system with a Molybdänfolieneinschmelzung in quartz glass, wherein a first end of the molybdenum foil embedded in the quartz glass with an electrode and a second end of this molybdenum foil is connected to a power supply wire.
  • the first end of the molybdenum foil connected to the electrode is wedge-shaped, that is to say it has a reduced thickness in order to reduce the risk of cracking in the glass due to the different thermal coefficients of quartz glass and molybdenum.
  • the publication GB 2 048 563 A discloses a discharge lamp having flattened end portions of electrodes and power leads connected to metal foils.
  • the Laid-open GB 2 002 954 A describes an electrode for a miniature discharge lamp welded to a flattened sheet-like part of a molybdenum power supply.
  • Patent US 3,868,528 discloses an electrode system for a discharge lamp in which a tapered molybdenum foil is connected to a flattened end of a power supply.
  • the electrode system comprises an electrode for generating a gas discharge and at least one metal foil, the first end of which is connected to the electrode and the second end of which is connected to a power supply wire which serves to energize the electrode.
  • the at least one metal foil has a reduced width at at least one of its abovementioned ends, but preferably at both its ends.
  • the width of the at least one metal foil is continuously reduced in the direction of its first or second end. Or in other words, this means that the width of the at least one metal foil, starting from its first or second end in the direction of the center of the metal foil increases steadily.
  • the at least one metal foil is tapered at its first and / or second end and, in addition to the reduction of the mechanical stresses in the glass during lamp operation, also facilitates easier threading of the electrode system into the still open end of the discharge vessel during the manufacturing process of the discharge lamp.
  • both the electrode and the power supply wire have a flattened portion which is welded to the first and second ends of the at least one metal foil.
  • the flattened ends of the electrode and the current supply wire are advantageously rounded.
  • the edge of the flattened portion of the electrode or the power supply wire is advantageously provided with a chamfer, which causes a reduction in the thickness of the flattened portion at its edge and thus also contributes to reducing mechanical stresses in the sealing region of the discharge vessel.
  • the minimum width of the at least one narrowed end of the at least one metal foil is preferably less than or equal to or width of the flattened portion of the electrode or power supply wire connected to that end.
  • the electrode system according to the invention is advantageously used for discharge lamps, in particular for high-pressure discharge lamps.
  • the discharge lamp according to the invention has a discharge vessel which is equipped with a discharge space and at least one sealed end provided with an electrode system according to the invention, the free end of the electrode projecting into the discharge space, the at least one metal foil gas-tight in the at least one sealed end of the discharge vessel is embedded and the free end of the power supply wire is led out of the sealed end of the discharge vessel.
  • the non-flattened portion of the electrode is advantageously arranged completely in the discharge space, while the flattened portion of the electrode preferably extends partially or completely into the sealed end of the discharge vessel. This also reduces the mechanical stresses in the sealed end of the discharge vessel during lamp operation, and also serves as the transition region from the flattened to the non-flattened portion of the electrode as a stop for the adjustment or alignment of the electrode in the discharge vessel.
  • the electrode system according to the invention is preferably used in discharge lamps which have a quartz glass discharge vessel, that is to say that the glass contains at least 95% by weight silicon dioxide.
  • Such discharge vessels withstand very high operating temperatures and are therefore usually used for high-pressure discharge lamps, for example metal halide high-pressure discharge lamps.
  • the electrodes of such a discharge lamp are preferably made of tungsten, which may contain dopants - for example, thorium oxide - or of a tungsten alloy.
  • Their power supply wires are preferably made of molybdenum, which may contain dopants - for example, potassium and silicon, or yttria or lanthanum oxide - or of a molybdenum alloy.
  • the at least one metal foil of the electrode system according to the invention preferably consists in this discharge lamp type of a molybdenum foil, the dopants - for example, potassium and silicon, or yttria or lanthanum oxide - may contain, or of a molybdenum alloy.
  • the aforementioned molybdenum foil can be provided on one or both sides with a coating, for example of chromium or ruthenium, in order to protect it from corrosion. These coatings may additionally be disposed on the flattened portion of the electrode or the power supply wire.
  • the method for producing the electrode system according to the invention provides that at least one end of the at least one metal foil is cut before joining the at least one metal foil to the electrode and the power supply wire such that the at least one metal foil has a reduced width at this end.
  • both the first and the second end of the at least one metal foil are cut in such a way that both ends have a reduced width.
  • the ends of the at least one metal foil are cut in such a way that the width of the at least one metal foil, starting from its first or second end in FIG Direction of the metal foil center steadily increases.
  • the portion of the electrode or / and the power supply wire to be connected to this metal foil is flattened prior to bonding to the metal foil, for example by cold forming by means of rolling or hammering.
  • the free ends of these sections are rounded by heating to a dome, for example by heating by means of a laser or TIG welding (tungsten inert gas welding) or by means of a plasma welding process.
  • the edge of the flattened portion of the electrode or / and the Stromzufihrungsdrahtes is preferably provided due to the advantages already mentioned above with a bevel, which is produced for example by rolling.
  • the connection between the at least one metal foil and the flattened portion of the electrode and / or the power supply wire is easily produced by welding, preferably by spot welding. This welded joint can be easily produced by means of a laser.
  • FIG. 1 shows a schematic representation of the preferred embodiment of the electrode system according to the invention, which is preferably used in a metal halide high-pressure discharge lamp for a vehicle headlamp.
  • the electrode system has a molybdenum foil 10 with longitudinal edges 11 and 12 defining a tapered first end 101 bounded by the sloping side edges 13, 14 and a tapered second end 102 bounded by the sloping side edges 15, 16. exhibit.
  • the cross section of this molybdenum foil 10 is lenticular. That is, their thickness steadily decreases, starting from their center line in the direction of their two side edges 11, 12.
  • the thickness in the middle of the film is less than 150 ⁇ m, preferably about 25 ⁇ m. It depends on the required current carrying capacity of the molybdenum foil 10.
  • the width of the molybdenum foil 10, that is, the distance between the longitudinal edges 11 and 12 is 2 mm.
  • the minimum width of the molybdenum foil 10 at its tapered ends 101 and 102 is at least 0.2 mm and is at most as wide as the width of the flattened ends 21, 31 of the electrode and the power supply wire.
  • the first end 101 of the molybdenum foil 10 is connected to a rod-shaped electrode 20 made of tungsten.
  • This electrode 20 has a flattened end 21, which is welded to the tapered first end 101 of the molybdenum foil 10 by two spot welds 41 made by means of a laser.
  • the electrode 20 has a diameter of about 0.25 mm in the non-flattened area 20.
  • the flattened portion 21 of the electrode 20 has a thickness of about 100 microns and a width of about 0.8 mm.
  • the second end 102 of the molybdenum foil 10 is connected to a molybdenum power supply wire 30.
  • This power supply wire 30 has a flattened end 31 which is welded to the tapered second end 102 of the molybdenum foil 10 by two welding spots 42 made by laser.
  • the Stromzufihrungsdraht 30 has in the non-flattened region 30 has a diameter of about 0.4 mm.
  • the free end of the flattened portion 21 of the electrode 20 is, as in FIGS Figures 2 and 3a shown schematically rounded. The same applies to the free end of the flattened portion 31 of the power supply wire 30.
  • the edge of the flattened portion 21 of the electrode 20 is, as in Figs FIGS. 3a and 3b shown schematically, provided with a chamfer 22 or chamfer, which has an angle or a slope of 45 degrees against the welded to the molybdenum foil 10 top of the portion 21.
  • FIG. 4a shows a molybdenum ribbon from which the molybdenum foil 10 is obtained by cutting a correspondingly long piece.
  • the obliquely extending side edges 13, 14 and 15, 16 are produced by punching out a V-shaped cutout of two adjacent molybdenum foils 10. Subsequently, the adjacent molybdenum foils 10 are cut apart.
  • the cut edges of the molybdenum foils 10 can be rolled as shown in FIG Laid-open publication EP 0 884 763 A2 is disclosed.
  • the tapered ends 101 and 102 are formed symmetrically. At the in FIG.
  • FIG. 5 a metal halide high pressure discharge lamp for a motor vehicle headlight is shown schematically.
  • This lamp has a discharge vessel 50 made of quartz glass with a discharge space 51 and two diametrically arranged, sealed ends 52, each having an electrode system according to the invention with an electrode 20 or 20 ", a molybdenum foil 10 or 10" and a power supply wire 30 or 30 "in the discharge space of the discharge vessel into which the free ends of the electrodes 20, 20 "project, an ionizable filling gas-tight, which contains xenon and metal halides, for example sodium iodide, scandium iodide and optionally further iodides, as well as mercury. However, the mercury can also be dispensed with.
  • xenon and metal halides for example sodium iodide, scandium iodide and optionally further iodides, as well as mercury.
  • the mercury can also be dispensed with.
  • the diameter of the non-flattened portions 21 and 31 of the electrodes 20, 20 "and power supply wires 30, 30" is about 0.33 mm, respectively.
  • the discharge vessel 50 is surrounded by an outer bulb 70, which consists of quartz glass, which is provided with ultraviolet radiation absorbing dopants.
  • the lamp has a plastic base 80, which carries the two lamp vessels 50, 80 and which is equipped with the electrical connections of the lamp.
  • the off-board power supply wire 30 is connected to one of the electrical terminals (not shown) via the current return 60 provided with a ceramic insulation 61, while the socket-proximate power supply wire 30 "is connected to the other electrical terminal (not shown).
  • the non-flattened portion of the electrode 20 or 20 is completely disposed in the discharge space 51 of the discharge vessel 50, while the flattened portion 21 of the electrode 20 or 20" extends into a respective sealed end 52 of the discharge vessel 50.
  • the two sealed ends 52 of the discharge vessel are so-called pinch seals or Molybdänfolieneinschmelzept.
  • the molybdenum foils 10 and 10 are embedded in a gastight manner in the respective end 52 of the discharge vessel 50.
  • the inner diameter of the essentially circular cylindrical discharge space 51 is 2.7 mm
  • the outer contour of the discharge vessel 50 has the shape of a rotationally symmetrical ellipsoid in the region of the discharge space 51.
  • the invention is not limited to the above-described preferred embodiment of the invention.
  • the ends of the molybdenum foils For example, the aforementioned ends of the molybdenum foils could be narrowed by making their edges curved, as in, for example, that in FIG FIG. 6 illustrated second embodiment of the invention is shown.
  • the ends of the molybdenum foil 10 "'to be connected to the electrode or the current supply wire are each delimited by a curved edge 101"', 102 ".
  • the curvature of these edges 101"', 102 "' can correspond, for example, to a conic section segment or in FIG. 6 shown having the shape of the letter U with diverging U-legs.
  • the flattening of the ends 21 and 31 of the electrode 20 and of the power supply wire 30 welded together with the molybdenum foils 10 or 10 is not absolutely necessary, it is possible to reduce the degree of flattening of the ends 21 or 31 welded to the molybdenum foils 10 or 10" 31 of the electrode 20 and the power supply wire 30 to vary.
  • the flattened ends 21 and 31 may have a thickness of only 80 .mu.m instead of the above-mentioned 100 .mu.m.
  • welding of the abovementioned ends 21 or 31 of the electrode 20 or of the power supply wire For example, when welding by means of a laser, the laser beam is directed to the molybdenum foil 10 or 10 "overlapping end 21 and 31 of the electrode 20 and the power supply wire 30, respectively, and not to the molybdenum foil 10 or 10 "to prevent perforation of the molybdenum foil 10 or 10".
  • the overlap area between the molybdenum foil 10 or 10 "and the abovementioned end 21 or 31 of the electrode 20 or of the power supply wire 30 in the preferred exemplary embodiments is 1 mm to 2 mm in the longitudinal direction of the molybdenum foil.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Vessels And Coating Films For Discharge Lamps (AREA)
  • Discharge Lamp (AREA)

Abstract

An electrode (20) serves to generate a gas discharge. A metal fusing/sealing foil (10) has its first end (101) linked to the electrode and its second end (102) linked to a current supply wire (30) for supplying power to the electrode. On one (101) of its ends the metal foil has a reduced width. Independent claims are also included for the following: (A) A gas discharge lamp with an electrode system; (B) and for a method for producing an electrode system for a gas discharge lamp.

Description

Die Erfindung betrifft ein Elektrodensystem für eine Entladungslampe gemäß dem Oberbegriff des Patentanspruchs 1 und eine Entladungslampe mit einem derartigen Elektrodensystem sowie ein Verfahren zur Herstellung eines derartigen Elektrodensystems.The invention relates to an electrode system for a discharge lamp according to the preamble of patent claim 1 and to a discharge lamp with such an electrode system and to a method for producing such an electrode system.

I. Stand der Technik I. State of the art

Ein derartiges Elektrodensystem ist beispielsweise in der europäischen Offenlegungsschrift EP 0 884 763 A2 offenbart. Diese Schrift beschreibt ein Elektrodensystem mit einer Molybdänfolieneinschmelzung in Quarzglas, wobei ein erstes Ende der im Quarzglas eingebetteten Molybdänfolie mit einer Elektrode und ein zweites Ende dieser Molybdänfolie mit einem Stromzuführungsdraht verbunden ist. Das mit der Elektrode verbundene erste Ende der Molybdänfolie ist keilförmig ausgebildet, das heißt, es weist eine reduzierte Dicke auf, um die Gefahr der Rissbildung im Glas aufgrund der unterschiedlichen thermischen AusdchnungskoefFzienten von Quarzglas und Molybdän, zu verringern.Such an electrode system is for example in the European patent application EP 0 884 763 A2 disclosed. This document describes an electrode system with a Molybdänfolieneinschmelzung in quartz glass, wherein a first end of the molybdenum foil embedded in the quartz glass with an electrode and a second end of this molybdenum foil is connected to a power supply wire. The first end of the molybdenum foil connected to the electrode is wedge-shaped, that is to say it has a reduced thickness in order to reduce the risk of cracking in the glass due to the different thermal coefficients of quartz glass and molybdenum.

Die Offenlegungsschrift GB 2 048 563 A offenbart eine Entladungslampe mit abgeflachten Endabschnitten von Elektroden und Stromzuführungen, die mit Metallfolien verbunden sind.The publication GB 2 048 563 A discloses a discharge lamp having flattened end portions of electrodes and power leads connected to metal foils.

Die Offenlegungsschrift GB 2 002 954 A beschreibt eine Elektrode für eine Miniatur-Entladungslampe, die mit einem abgeflachten, folienartigen Teil einer Molybdänstromzuführung verschweißt ist.The Laid-open GB 2 002 954 A describes an electrode for a miniature discharge lamp welded to a flattened sheet-like part of a molybdenum power supply.

Die Patentschrift US 3,868,528 offenbart ein Elektrodensystem für eine Entladungslampe, bei dem eine verjüngte Molybdänfolie mit einem abgeflachten Ende einer Stromzuführung verbunden ist.The Patent US 3,868,528 discloses an electrode system for a discharge lamp in which a tapered molybdenum foil is connected to a flattened end of a power supply.

II. Darstellung der Erfindung II. Presentation of the invention

Es ist die Aufgabe der Erfindung, ein verbessertes Elektrodensystem für eine Entladungslampe bereitzustellen, das eine weitere Verringerung der Gefahr der Rissbildung im Glas des Entladungsgefäßes der Entladungslampe ermöglicht. Außerdem ist es die Aufgabe der Erfindung, ein Herstellungsverfahren für ein derartiges Elektrodensystem bereitzustellen.It is the object of the invention to provide an improved electrode system for a discharge lamp, which allows a further reduction of the risk of cracking in the glass of the discharge vessel of the discharge lamp. In addition, it is the object of the invention to provide a manufacturing method for such an electrode system.

Diese Aufgabe wird erfindungsgemäß durch die Merkmale des Patentanspruchs 1 gelöst. Besonders vorteilhafte Ausführungen der Erfindung sind in den abhängigen Patentansprüchen beschrieben.This object is achieved by the features of claim 1. Particularly advantageous embodiments of the invention are described in the dependent claims.

Das erfindungsgemäße Elektrodensystem weist eine zur Erzeugung einer Gasentladung dienende Elektrode und mindestens eine Metallfolie auf, deren erstes Ende mit der Elektrode verbunden ist und deren zweites Ende mit einem Stromzufiihrungsdraht, der zur Energieversorgung der Elektrode dient, verbunden ist. Erfindungsgemäß weist die mindestens eine Metallfolie an mindestens einem ihrer vorgenannten Enden, vorzugsweise aber an beiden ihrer Enden, eine reduzierte Breite auf. Dadurch können die durch ihre unterschiedlichen thermischen Ausdehnungskoeffizienten hervorgerufenen mechanischen Spannungen zwischen dieser Metallfolie und dem Glas des Entladungsgefäßes, in dem diese Metallfolie gasdicht eingebettet werden muss, deutlich verringert werden, so dass eine zum Ausfall der Entladungslampe führende Rissbildung in dem Glas des Entladungsgefäßes während des Lampenbetriebs vermieden wird.The electrode system according to the invention comprises an electrode for generating a gas discharge and at least one metal foil, the first end of which is connected to the electrode and the second end of which is connected to a power supply wire which serves to energize the electrode. According to the invention, the at least one metal foil has a reduced width at at least one of its abovementioned ends, but preferably at both its ends. As a result, the mechanical stresses caused by their different coefficients of thermal expansion between this metal foil and the glass of the discharge vessel in which this metal foil has to be embedded gas-tight can be significantly reduced, so that cracking in the glass of the discharge vessel during lamp operation results in failure of the discharge lamp is avoided.

In vorteilhafter Weise wird die Breite der mindestens einen Metallfolie in Richtung ihres ersten oder zweiten Endes stetig verkleinert. Oder mit anderen Worten formuliert bedeutet das, dass die Breite der mindestens einen Metallfolie, ausgehend von ihrem ersten oder zweiten Ende in Richtung der Metallfolienmitte stetig zunimmt. Durch die vorgenannte stetige Veränderung der Metallfolienbreite ist die mindestens eine Metallfolie an ihrem ersten oder / und zweiten Ende verjüngt und ermöglicht dadurch, zusätzlich zur Reduktion der mechanischen Spannungen im Glas während des Lampenbetriebs, auch ein leichteres Einfädeln des Elektrodensystems in das noch offene Ende des Entladungsgefäßes während des Herstellungsprozesses der Entladungslampe.Advantageously, the width of the at least one metal foil is continuously reduced in the direction of its first or second end. Or in other words, this means that the width of the at least one metal foil, starting from its first or second end in the direction of the center of the metal foil increases steadily. As a result of the abovementioned continuous change in the metal foil width, the at least one metal foil is tapered at its first and / or second end and, in addition to the reduction of the mechanical stresses in the glass during lamp operation, also facilitates easier threading of the electrode system into the still open end of the discharge vessel during the manufacturing process of the discharge lamp.

Der mit dem verschmälerten Ende der mindestens einen Metallfolie verbundene Abschnitt der Elektrode beziehungsweise des Stromzuführungsdrahtes ist in vorteilhafter Weise abgeflacht ausgebildet, um eine ausreichend große Kontaktfläche zwischen der mindestens einen Metallfolie und der Elektrode beziehungsweise dem Stromzuführungsdraht zur Herstellung einer Schweißverbindung zwischen den vorgenannten Bauteilen zu gewährleisten. Gemäß des bevorzugten Ausführungsbeispiels der Erfindung weisen daher sowohl die Elektrode als auch der Stromzuführungsdraht einen abgeflachten Abschnitt, der mit dem ersten bzw. zweiten Ende der mindestens einen Metallfolie verschweißt ist.The portion of the electrode or the power supply wire connected to the narrowed end of the at least one metal foil is advantageously flattened to provide a sufficiently large contact area between the at least one metal foil and the electrode or the power supply wire for producing a welded connection between the aforementioned To ensure components. Therefore, according to the preferred embodiment of the invention, both the electrode and the power supply wire have a flattened portion which is welded to the first and second ends of the at least one metal foil.

Zur weiteren Reduktion der während des Lampenbetriebs auftretenden mechanischen Spannungen in dem Abdichtungsbereich des Entladungsgefäßes, sind die abgeflachten Enden der Elektrode und des Stromzuführungsdrahtes in vorteilhafter Weise abgerundet ausgebildet. Außerdem ist die Kante des abgeflachten Abschnitts der Elektrode beziehungsweise des Stromzuführungsdrahtes in vorteilhafter Weise mit einer Fase versehen, die eine Reduktion der Dicke des abgeflachten Abschnitts an seiner Kante bewirkt und damit ebenfalls zur Verringerung mechanischer Spannungen in dem Abdichtungsbereich des Entladungsgefäßes beiträgt. Ferner ist aus demselben Grund die minimale Breite des mindestens einen verschmälerten Endes der mindestens einen Metallfolie vorzugsweise kleiner oder gleich oder Breite des mit diesem Ende verbundenen, abgeflachten Abschnitts der Elektrode beziehungsweise des Stromzuführungsdrahtes.To further reduce the mechanical stresses occurring in the sealing region of the discharge vessel during lamp operation, the flattened ends of the electrode and the current supply wire are advantageously rounded. In addition, the edge of the flattened portion of the electrode or the power supply wire is advantageously provided with a chamfer, which causes a reduction in the thickness of the flattened portion at its edge and thus also contributes to reducing mechanical stresses in the sealing region of the discharge vessel. Further, for the same reason, the minimum width of the at least one narrowed end of the at least one metal foil is preferably less than or equal to or width of the flattened portion of the electrode or power supply wire connected to that end.

Das erfindungsgemäße Elektrodensystem wird in vorteilhafter Weise für Entladungslampen, insbesondere für Hochdruckentladungslampen verwendet.The electrode system according to the invention is advantageously used for discharge lamps, in particular for high-pressure discharge lamps.

Die erfindungsgemäße Entladungslampe weist ein Entladungsgefäß auf, das mit einem Entladungsraum und mindestens einem abgedichteten, mit einem erfindungsgemäßen Elektrodensystem versehenen Ende ausgestattet ist, wobei das freie Ende der Elektrode in den Entladungsraum hineinragt, die mindestens eine Metallfolie gasdicht in dem mindestens einen abgedichteten Ende des Entladungsgefäßes eingebettet ist und das freie Ende des Stromzuführungsdrahtes aus dem abgedichteten Ende des Entladungsgefäßes herausgeführt ist. Der nicht-abgeflachte Abschnitt der Elektrode ist in vorteilhafter Weise vollständig in dem Entladungsraum angeordnet, während sich der abgeflachte Abschnitt der Elektrode vorzugsweise teilweise oder vollständig in das abgedichtete Ende des Entladungsgefäßes erstreckt. Dadurch werden ebenfalls die mechanischen Spannungen in dem abgedichteten Ende des Entladungsgefäßes während des Lampenbetriebs verringert und außerdem dient der Übergangsbereich von dem abgeflachten zum nicht-abgeflachten Abschnitt der Elektrode als Anschlag für die Justage bzw. Ausrichtung der Elektrode in dem Entladungsgefäß.The discharge lamp according to the invention has a discharge vessel which is equipped with a discharge space and at least one sealed end provided with an electrode system according to the invention, the free end of the electrode projecting into the discharge space, the at least one metal foil gas-tight in the at least one sealed end of the discharge vessel is embedded and the free end of the power supply wire is led out of the sealed end of the discharge vessel. The non-flattened portion of the electrode is advantageously arranged completely in the discharge space, while the flattened portion of the electrode preferably extends partially or completely into the sealed end of the discharge vessel. This also reduces the mechanical stresses in the sealed end of the discharge vessel during lamp operation, and also serves as the transition region from the flattened to the non-flattened portion of the electrode as a stop for the adjustment or alignment of the electrode in the discharge vessel.

Das erfindungsgemäße Elektrodensystem wird vorzugsweise in Entladungslampen eingesetzt, die ein Entladungsgefäß aus Quarzglas besitzen, das heißt, dass das Glas mindestens 95 Gewichtsprozent Siliziumdioxid enthält. Derartige Entladungsgefäße halten sehr hohen Betriebstemperaturen stand und werden daher üblicherweise für Hochdruckentladungslampen, beispielsweise Halogen-Metalldampf Hochdruckentladungslampen verwendet. Die Elektroden einer derartigen Entladungslampe bestehen vorzugsweise aus Wolfram, das Dotierstoffe - beispielsweise Thoriumoxid - enthalten kann, oder aus einer Wolframlegierung. Ihre Stromzuführungsdrähte bestehen vorzugsweise aus Molybdän, das Dotierstoffe - beispielweise Kalium und Silizium, oder Yttriumoxid oder Lanthanoxid - enthalten kann, oder aus einer Molybdänlegierung. Die mindestens eine Metallfolie des erfindungsgemäßen Elektrodensystems besteht bei diesem Entladungslampentyp vorzugsweise aus einer Molybdänfolie, die Dotierstoffe - beispielweise Kalium und Silizium, oder Yttriumoxid oder Lanthanoxid - enthalten kann, oder aus einer Molybdänlegierung. Die vorgenannte Molybdänfolie kann einseitig oder beidseitig mit einer Beschichtung - beispielsweise aus Chrom oder Ruthenium - versehen sein, um sie vor Korrosion zu schützen. Diese Beschichtungen können zusätzlich auf dem abgeflachten Abschnitt der Elektrode oder des Stromzuführungsdrahtes angeordnet sein.The electrode system according to the invention is preferably used in discharge lamps which have a quartz glass discharge vessel, that is to say that the glass contains at least 95% by weight silicon dioxide. Such discharge vessels withstand very high operating temperatures and are therefore usually used for high-pressure discharge lamps, for example metal halide high-pressure discharge lamps. The electrodes of such a discharge lamp are preferably made of tungsten, which may contain dopants - for example, thorium oxide - or of a tungsten alloy. Their power supply wires are preferably made of molybdenum, which may contain dopants - for example, potassium and silicon, or yttria or lanthanum oxide - or of a molybdenum alloy. The at least one metal foil of the electrode system according to the invention preferably consists in this discharge lamp type of a molybdenum foil, the dopants - for example, potassium and silicon, or yttria or lanthanum oxide - may contain, or of a molybdenum alloy. The aforementioned molybdenum foil can be provided on one or both sides with a coating, for example of chromium or ruthenium, in order to protect it from corrosion. These coatings may additionally be disposed on the flattened portion of the electrode or the power supply wire.

Das Verfahren zur Herstellung des erfindungsgemäßen Elektrodensystems sieht vor, dass vor dem Verbinden der mindestens einen Metallfolie mit der Elektrode und dem Stromzuführungsdraht mindestens ein Ende der mindestens einen Metallfolie derart zugeschnitten wird, dass die mindestens eine Metallfolie an diesem Ende eine reduziert Breite aufweist. Vorzugsweise werden aber sowohl das erste als auch das zweite Ende der mindestens einen Metallfolie derart zugeschnitten, dass beide Enden eine reduzierte Breite aufweisen. Aus den bereits oben genannten Gründen werden die Enden der mindestens einen Metallfolie derart zugeschnitten, dass die Breite der mindestens einen Metallfolie, ausgehend von ihrem ersten oder zweiten Ende in Richtung der Metallfolienmitte stetig zunimmt. Der mit dieser Metallfolie zu verbindende Abschnitt der Elektrode oder / und des Stromzuführungsdrahtes wird vor dem Verbinden mit der Metallfolie abgeflacht, beispielsweise durch Kaltverformen mittels Walzen oder Hämmern. Vorzugsweise werden vor dem Abflachen der vorgenannten Abschnitte der Elektroden oder / und des Stromzufiihrungsdrahtes die freien Enden dieser Abschnitte durch Erhitzen zu einer Kuppe abgerundet, beispielsweise durch Erhitzen mittels eines Lasers oder mittels WIG-Schweißen (Wolfram-Inertgas-Schweißen) oder mittels eines Plasma-Schweißverfahrens. Die Kante des abgeflachten Abschnitts der Elektrode oder / und des Stromzufiihrungsdrahtes wird aufgrund der bereits oben genannte Vorteile vorzugsweise mit einer Fase versehen, die beispielsweise durch Walzen hergestellt wird. Die Verbindung zwischen der mindestens einen Metallfolie und dem abgeflachten Abschnitt der Elektrode oder / und des Stromzuführungsdrahtes wird in einfacher Weise durch Schweißen, vorzugsweise durch Punktschweißen hergestellt. Diese Schweißverbindung lässt sich auf einfache Weise mittels eines Lasers herstellen.The method for producing the electrode system according to the invention provides that at least one end of the at least one metal foil is cut before joining the at least one metal foil to the electrode and the power supply wire such that the at least one metal foil has a reduced width at this end. Preferably, however, both the first and the second end of the at least one metal foil are cut in such a way that both ends have a reduced width. For the reasons already mentioned above, the ends of the at least one metal foil are cut in such a way that the width of the at least one metal foil, starting from its first or second end in FIG Direction of the metal foil center steadily increases. The portion of the electrode or / and the power supply wire to be connected to this metal foil is flattened prior to bonding to the metal foil, for example by cold forming by means of rolling or hammering. Preferably, before flattening the aforementioned portions of the electrodes and / or the Stromzufihrungsdrahtes the free ends of these sections are rounded by heating to a dome, for example by heating by means of a laser or TIG welding (tungsten inert gas welding) or by means of a plasma welding process. The edge of the flattened portion of the electrode or / and the Stromzufihrungsdrahtes is preferably provided due to the advantages already mentioned above with a bevel, which is produced for example by rolling. The connection between the at least one metal foil and the flattened portion of the electrode and / or the power supply wire is easily produced by welding, preferably by spot welding. This welded joint can be easily produced by means of a laser.

III. Beschreibung des bevorzugten Ausführungsbeispiels III. Description of the Preferred Embodiment

Nachstehend wird die Erfindung anhand eines bevorzugten Ausführungsbeispiels näher erläutert. Es zeigen:

Figur 1
eine Draufsicht auf ein Elektrodensystem gemäß des bevorzugten Ausführungsbeispiels in schematischer Darstellung
Figur 2
eine Seitenansicht eines Ausschnitts des in Figur 1 abgebildeten Elektrodensystems in schematischer, teilweise geschnittener Darstellung
Figur 3a
eine Draufsicht auf den abgeflachten Abschnitt der Elektrode des in Figur 1 abgebildeten Elektrodensystems
Figur 3b
eine Draufsicht auf die Stirnseite des in Figur 3a abgebildeten abgeflachten Endes der Elektrode
Figur 4a
eine Draufsicht auf ein Molybdänband mit mehreren zusammenhängenden Molybdänfolien für das in Figur 1 abgebildete Elektrodensystem
Figur 4b
eine Draufsicht auf ein Molybdänband mit mehreren zusammenhängenden Molybdänfolien für das Elektrodensystem gemäß eines zweiten Ausführungsbeispiels
Figur 5
eine schematische Seitenansicht einer Hochdruckentladungslampe gemäß eines bevorzugten Ausführungsbeispiels, die zwei der in der Figur 1 abgebildeten Elektrodensysteme aufweist
Figur 6
eine Draufsicht auf eine alternative Molybdänfolie, die anstelle der in Figur 1 abgebildeten Molybdänfolie für das erfindungsgemäße Elektrodensystem verwendbar ist
The invention will be explained in more detail below with reference to a preferred embodiment. Show it:
FIG. 1
a plan view of an electrode system according to the preferred embodiment in a schematic representation
FIG. 2
a side view of a section of the in FIG. 1 shown electrode system in a schematic, partially sectioned representation
FIG. 3a
a plan view of the flattened portion of the electrode of FIG. 1 illustrated electrode system
FIG. 3b
a plan view of the front side of in FIG. 3a imaged flattened end of the electrode
FIG. 4a
a plan view of a molybdenum ribbon with several contiguous molybdenum foils for in FIG. 1 illustrated electrode system
FIG. 4b
a top view of a molybdenum ribbon with several contiguous molybdenum foils for the electrode system according to a second embodiment
FIG. 5
a schematic side view of a high-pressure discharge lamp according to a preferred embodiment, the two of the in the FIG. 1 having pictured electrode systems
FIG. 6
a plan view of an alternative molybdenum foil, instead of the in FIG. 1 imaged molybdenum foil is usable for the electrode system according to the invention

Die Figur 1 zeigt eine schematische Darstellung der bevorzugten Ausführungsform des erfindungsgemäßen Elektrodensystems, das vorzugsweise in einer Halogen-Metalldampf-Hochdruckentladungslampe für einen Fahrzeugscheinwerfer verwendet wird.The FIG. 1 shows a schematic representation of the preferred embodiment of the electrode system according to the invention, which is preferably used in a metal halide high-pressure discharge lamp for a vehicle headlamp.

Das Elektrodensystem besitzt eine Molybdänfolie 10 mit Längskanten 11 und 12, die ein verjüngtes erstes Ende 101, das durch die schräg verlaufenden Seitenkanten 13, 14 begrenzt ist, und ein verjüngtes zweites Ende 102, das durch die schräg verlaufenden Seitenkanten 15, 16 begrenzt ist, aufweisen. Der Querschnitt dieser Molybdänfolie 10 ist linsenförmig. Das heißt, dass ihre Dicke, ausgehend von ihrer Mittellinie in Richtung ihrer beiden Seitenkanten 11, 12 hin, stetig abnimmt. Die Dicke in der Folienmitte beträgt weniger als 150 µm, vorzugsweise ca. 25 µm. Sie hängt von der erforderlichen Stromtragfähigkeit der Molybdänfolie 10 ab. Die Breite der Molybdänfolie 10, das heißt, der Abstand zwischen den Längskanten 11 und 12 beträgt 2 mm. Die minimale Breite der Molybdänfolie 10 an ihren verjüngten Enden 101 und 102 beträgt mindestens 0,2 mm und ist maximal so breit wie die Breite der abgeflachten Enden 21, 31 der Elektrode und des Stromzuführungsdrahtes.The electrode system has a molybdenum foil 10 with longitudinal edges 11 and 12 defining a tapered first end 101 bounded by the sloping side edges 13, 14 and a tapered second end 102 bounded by the sloping side edges 15, 16. exhibit. The cross section of this molybdenum foil 10 is lenticular. That is, their thickness steadily decreases, starting from their center line in the direction of their two side edges 11, 12. The thickness in the middle of the film is less than 150 μm, preferably about 25 μm. It depends on the required current carrying capacity of the molybdenum foil 10. The width of the molybdenum foil 10, that is, the distance between the longitudinal edges 11 and 12 is 2 mm. The minimum width of the molybdenum foil 10 at its tapered ends 101 and 102 is at least 0.2 mm and is at most as wide as the width of the flattened ends 21, 31 of the electrode and the power supply wire.

Das erste Ende 101 der Molybdänfolie 10 ist mit einer stabförmigen Elektrode 20 aus Wolfram verbunden. Diese Elektrode 20 weist ein abgeflachtes Ende 21 auf, das durch zwei Schweißpunkte 41, die mittels eines Lasers hergestellt wurden, mit dem verjüngten ersten Ende 101 der Molybdänfolie 10 verschweißt ist. Die Elektrode 20 besitzt im nicht-abgeflachten Bereich 20 einen Durchmesser von ungefähr 0,25 mm. Der abgeflachte Abschnitt 21 der Elektrode 20 besitzt eine Dicke von ca. 100 µm und eine Breite von ca. 0,8 mm.The first end 101 of the molybdenum foil 10 is connected to a rod-shaped electrode 20 made of tungsten. This electrode 20 has a flattened end 21, which is welded to the tapered first end 101 of the molybdenum foil 10 by two spot welds 41 made by means of a laser. The electrode 20 has a diameter of about 0.25 mm in the non-flattened area 20. The flattened portion 21 of the electrode 20 has a thickness of about 100 microns and a width of about 0.8 mm.

Das zweite Ende 102 der Molybdänfolie 10 ist mit einem Stromzufiihrungsdraht 30 aus Molybdän verbunden. Dieser Stromzuführungsdraht 30 weist ein abgeflachtes Ende 31 auf, das durch zwei Schweißpunkte 42, die mittels eines Lasers hergestellt wurden, mit dem verjüngten zweiten Ende 102 der Molybdänfolie 10 verschweißt ist. Der Stromzufiihrungsdraht 30 besitzt im nicht-abgeflachten Bereich 30 einen Durchmesser von ungefähr 0,4 mm.The second end 102 of the molybdenum foil 10 is connected to a molybdenum power supply wire 30. This power supply wire 30 has a flattened end 31 which is welded to the tapered second end 102 of the molybdenum foil 10 by two welding spots 42 made by laser. The Stromzufihrungsdraht 30 has in the non-flattened region 30 has a diameter of about 0.4 mm.

Das freie Ende des abgeflachten Abschnitts 21 der Elektrode 20 ist, wie in den Figuren 2 und 3a schematisch dargestellt, abgerundet ausgebildet. Das Gleiche gilt auch für das freie Ende des abgeflachten Abschnitts 31 des Stromzuführungsdrahtes 30. Die Kante des abgeflachten Abschnitts 21 der Elektrode 20 ist, wie in den Figuren 3a und 3b schematisch dargestellt, mit einer Fase 22 oder Abschrägung versehen, die einen Winkel oder eine Neigung von 45 Grad gegen die mit der Molybdänfolie 10 verschweißte Oberseite des Abschnitts 21 aufweist.The free end of the flattened portion 21 of the electrode 20 is, as in FIGS Figures 2 and 3a shown schematically rounded. The same applies to the free end of the flattened portion 31 of the power supply wire 30. The edge of the flattened portion 21 of the electrode 20 is, as in Figs FIGS. 3a and 3b shown schematically, provided with a chamfer 22 or chamfer, which has an angle or a slope of 45 degrees against the welded to the molybdenum foil 10 top of the portion 21.

Die Figur 4a zeigt ein Molybdänband, aus dem die Molybdänfolie 10 durch Abschneiden eines entsprechend langen Stückes gewonnen wird. Die schräg verlaufenden Seitenkanten 13, 14 bzw. 15, 16 werden dabei durch Ausstanzen eines V-förmigen Ausschnittes aus zwei angrenzenden Molybdänfolien 10 erzeugt. Anschließend werden die benachbarten Molybdänfolien 10 auseinander geschnitten. Die Schnittkanten der Molybdänfolien 10 können gewalzt werden, wie in der Offenlegungsschrift EP 0 884 763 A2 offenbart ist. Bei der Molybdänfolie 10 sind die verjüngten Enden 101 und 102 symmetrisch ausgebildet. Bei dem in Figur 4b abgebildeten Molybdänfolien 10' bilden die schräg verlaufenden Seitenkanten 13', 14' und 15', 16' unterschiedliche Winkel mit den Längskanten der Molybdänfolie 10'. Dementsprechend sind ihre verjüngten Enden unsymmetrisch ausgebildet.The FIG. 4a shows a molybdenum ribbon from which the molybdenum foil 10 is obtained by cutting a correspondingly long piece. The obliquely extending side edges 13, 14 and 15, 16 are produced by punching out a V-shaped cutout of two adjacent molybdenum foils 10. Subsequently, the adjacent molybdenum foils 10 are cut apart. The cut edges of the molybdenum foils 10 can be rolled as shown in FIG Laid-open publication EP 0 884 763 A2 is disclosed. In the molybdenum foil 10, the tapered ends 101 and 102 are formed symmetrically. At the in FIG. 4b molybdenum foils 10 'shown, the oblique side edges 13', 14 'and 15', 16 'form different angles with the longitudinal edges of the molybdenum foil 10'. Accordingly, their tapered ends are formed asymmetrically.

In der Figur 5 ist eine Halogen-Metalldampf-Hochdruckentladungslampe für einen Kraftfahrzeugscheinwerfer schematisch abgebildet. Diese Lampe besitzt ein Entladungsgefäß 50 aus Quarzglas mit einem Entladungsraum 51 und zwei diametral angeordneten, abgedichteten Enden 52, die jeweils ein erfindungsgemäßen Elektrodensystem mit einer Elektrode 20 bzw. 20", einer Molybdänfolie 10 bzw. 10" und einem Stromzuführungsdraht 30 bzw. 30" aufweisen. In dem Entladungsraum des Entladungsgefäßes, in den die freien Enden der Elektroden 20, 20" hineinragen, ist eine ionisierbare Füllung gasdicht eingeschlossen, die Xenon und Metallhalogenide, beispielsweise Natriumjodid, Scandiumjodid und ggf. weitere Jodide, sowie Quecksilber enthält. Auf das Quecksilber kann allerdings auch verzichtet werden. Dann beträgt der Durchmesser der nicht-abgeflachten Abschnitte 21 bzw. 31 der Elektroden 20, 20" und Stromzuführungsdrähte 30, 30" allerdings ungefähr 0,33 mm. Das Entladungsgefäß 50 ist von einem Außenkolben 70 umgeben, der aus Quarzglas besteht, das mit Ultraviolettstrahlung absorbierenden Dotierstoffen versehen ist. Die Lampe besitzt einen Kunststoffsockel 80, der die beiden Lampengefäße 50, 80 trägt und der mit den elektrischen Anschlüssen der Lampe ausgestattet ist. Der sockelferne Stromzuführungsdraht 30 ist über die mit einer Keramikisolierung 61 versehene Stromrückführung 60 mit einem der elektrischen Anschlüsse (nicht abgebildet) verbunden, während der sockelnahe Stromzuführungsdraht 30" mit dem anderen elektrischen Anschluss (nicht abgebildet) verbunden ist.In the FIG. 5 a metal halide high pressure discharge lamp for a motor vehicle headlight is shown schematically. This lamp has a discharge vessel 50 made of quartz glass with a discharge space 51 and two diametrically arranged, sealed ends 52, each having an electrode system according to the invention with an electrode 20 or 20 ", a molybdenum foil 10 or 10" and a power supply wire 30 or 30 "in the discharge space of the discharge vessel into which the free ends of the electrodes 20, 20 "project, an ionizable filling gas-tight, which contains xenon and metal halides, for example sodium iodide, scandium iodide and optionally further iodides, as well as mercury. However, the mercury can also be dispensed with. Then, the diameter of the non-flattened portions 21 and 31 of the electrodes 20, 20 "and power supply wires 30, 30" is about 0.33 mm, respectively. The discharge vessel 50 is surrounded by an outer bulb 70, which consists of quartz glass, which is provided with ultraviolet radiation absorbing dopants. The lamp has a plastic base 80, which carries the two lamp vessels 50, 80 and which is equipped with the electrical connections of the lamp. The off-board power supply wire 30 is connected to one of the electrical terminals (not shown) via the current return 60 provided with a ceramic insulation 61, while the socket-proximate power supply wire 30 "is connected to the other electrical terminal (not shown).

Wie in Figur 2 dargestellt, ist der nicht-abgeflachte Abschnitt der Elektrode 20 bzw. 20" vollständig im Entladungsraum 51 des Entladungsgefäßes 50 angeordnet, während sich der abgeflachte Abschnitt 21 der Elektrode 20 bzw. 20" in jeweils ein abgedichtetes Ende 52 des Entladungsgefäßes 50 erstreckt. Bei den beiden abgedichteten Enden 52 des Entladungsgefäßes handelt es sich um sogenannte Quetschdichtungen oder Molybdänfolieneinschmelzungen. Die Molybdänfolien 10 bzw. 10" sind gasdicht in dem jeweiligen Ende 52 des Entladungsgefäßes 50 eingebettet. Der Innendurchmesser des im wesentlichen kreiszylindrischen Entladungsraumes 51 beträgt 2,7 mm. Die Außenkontur des Entladungsgefäßes 50 besitzt im Bereich des Entladungsraumes 51 die Form eines rotationssymmetrischen Ellipsoids.As in FIG. 2 11, the non-flattened portion of the electrode 20 or 20 "is completely disposed in the discharge space 51 of the discharge vessel 50, while the flattened portion 21 of the electrode 20 or 20" extends into a respective sealed end 52 of the discharge vessel 50. The two sealed ends 52 of the discharge vessel are so-called pinch seals or Molybdänfolieneinschmelzungen. The molybdenum foils 10 and 10 "are embedded in a gastight manner in the respective end 52 of the discharge vessel 50. The inner diameter of the essentially circular cylindrical discharge space 51 is 2.7 mm The outer contour of the discharge vessel 50 has the shape of a rotationally symmetrical ellipsoid in the region of the discharge space 51.

Die Erfindung beschränkt sich nicht auf das oben näher erläuterte bevorzugte Ausführungsbeispiel der Erfindung. Beispielsweise können die Enden der Molybdänfolien 10 bzw. 10" anstatt keilartig verschmälert auch auf andere Weise verjüngt ausgebildet sein. Zum Beispiel könnten die vorgenannten Enden der Molybdänfolien verschmälert werden, indem ihre Kanten gewölbt ausgebildet werden bzw. mit Rundungen versehen werden, wie das beispielsweise in dem in Figur 6 abgebildeten zweiten Ausführungsbeispiel der Erfindung dargestellt ist. Die mit der Elektrode bzw. dem Stromzufiihrungsdraht zu verbindenden Enden der Molybdänfolie 10"' sind jeweils durch eine gewölbte Kante 101"', 102'" begrenzt. Die Wölbung dieser Kanten 101"', 102"' kann beispielsweise einem Kegelschnittsegment entsprechen oder, wie in Figur 6 abgebildet, die Gestalt des Buchstabens U mit auseinanderlaufenden U-Schenkeln aufweisen.The invention is not limited to the above-described preferred embodiment of the invention. For example, the ends of the molybdenum foils For example, the aforementioned ends of the molybdenum foils could be narrowed by making their edges curved, as in, for example, that in FIG FIG. 6 illustrated second embodiment of the invention is shown. The ends of the molybdenum foil 10 "'to be connected to the electrode or the current supply wire are each delimited by a curved edge 101"', 102 ".The curvature of these edges 101"', 102 "' can correspond, for example, to a conic section segment or in FIG. 6 shown having the shape of the letter U with diverging U-legs.

Das Abflachen der mit den Molybdänfolien 10 bzw. 10" verschweißten Enden 21 bzw. 31 der Elektrode 20 und des Stromzuführungsdrahtes 30 ist nicht unbedingt erforderlich. Es ist möglich, den Grad der Abflachung der mit den Molybdänfolien 10 bzw. 10" verschweißten Enden 21 bzw. 31 der Elektrode 20 und des Stromzuführungsdrahtes 30 zu variieren. Beispielsweise können die abgeflachten Enden 21 bzw. 31 eine Dicke von nur 80 µm anstelle der oben angegebenen 100 µm besitzen. Es ist aber auch möglich, auf das Abflachen der mit den Molybdänfolien 10 bzw. 10" verschweißten Enden 21 bzw. 31 der Elektrode 20 und des Stromzuführungsdrahtes 30 zu verzichten. Das Verschweißen der vorgenannten Enden 21 bzw. 31 der Elektrode 20 bzw. des Stromzuführungsdrahtes 30 kann beispielsweise mittels eines Widerstandsverfahrens oder eines Laserschweißverfahrens durchgeführt werden. Beim Verschweißen mittels eines Lasers wird der Laserstrahl auf das mit der Molybdänfolie 10 bzw. 10" überlappende Ende 21 bzw. 31 der Elektrode 20 bzw. des Stromzuführungsdrahtes 30 gerichtet und nicht auf die Molybdänfolie 10 bzw. 10", um ein Durchlöchern der Molybdänfolie 10 bzw. 10" zu verhindern. Der Überlappungsbereich zwischen der Molybdänfolie 10 bzw. 10" und dem vorgenannten Ende 21 bzw. 31 der Elektrode 20 bzw. des Stromzuführungsdrahtes 30 beträgt bei den bevorzugten Ausführungsbeispielen in Längsrichtung der Molybdänfolie 1 mm bis 2 mm.The flattening of the ends 21 and 31 of the electrode 20 and of the power supply wire 30 welded together with the molybdenum foils 10 or 10 "is not absolutely necessary, it is possible to reduce the degree of flattening of the ends 21 or 31 welded to the molybdenum foils 10 or 10" 31 of the electrode 20 and the power supply wire 30 to vary. For example, the flattened ends 21 and 31 may have a thickness of only 80 .mu.m instead of the above-mentioned 100 .mu.m. However, it is also possible to dispense with the flattening of the ends 21 and 31 of the electrode 20 and the power supply wire 30 welded together with the molybdenum foils 10 and 10, respectively. Welding of the abovementioned ends 21 or 31 of the electrode 20 or of the power supply wire For example, when welding by means of a laser, the laser beam is directed to the molybdenum foil 10 or 10 "overlapping end 21 and 31 of the electrode 20 and the power supply wire 30, respectively, and not to the molybdenum foil 10 or 10 "to prevent perforation of the molybdenum foil 10 or 10". The overlap area between the molybdenum foil 10 or 10 "and the abovementioned end 21 or 31 of the electrode 20 or of the power supply wire 30 in the preferred exemplary embodiments is 1 mm to 2 mm in the longitudinal direction of the molybdenum foil.

Claims (12)

  1. Electrode system for a discharge lamp, the electrode system having an electrode (20), which serves the purpose of producing a gas discharge, and at least one metal foil (10), whose first end (101) is connected to the electrode (20), and whose second end (102) is connected to a power supply wire (30), which serves the purpose of supplying power to the electrode (20), and the at least one metal foil (10) having a reduced width at at least one of its ends (101), and the section (21, 31) of the electrode (20) or of the power supply wire (30) which is connected to the narrowed end (101) of the at least one metal foil (10) being flattened, characterized in that an edge of the flattened section (21) of the electrode (20) and/or of the power supply wire (30) has a bevel (22).
  2. Electrode system according to Claim 1, characterized in that the at least one metal foil (10) has a reduced width both at its first (101) and at its second end (102).
  3. Electrode system according to Claim 1 or 2, characterized in that the width of the at least one metal foil (10) continuously increases, starting from its first (101) or second end (102) in the direction of the metal foil center.
  4. Electrode system according to Claim 2, characterized in that the section (21) of the electrode which is connected to the narrowed first end (101) of the at least one metal foil (10) and the section (31) of the power supply wire (30) which is connected to the narrowed second end (102) of the at least one metal foil (10) are flattened.
  5. Electrode system according to Claim 1 or 4, characterized in that the flattened section (21, 31) of the electrode (20) and/or of the power supply wire (30) has a rounded-off end.
  6. Electrode system according to Claim 1 or 2, characterized in that the smallest width of the at least one narrowed end (101) of the at least one metal foil (10) is smaller than or equal to the width of the flattened section (21, 31), which is connected to this end (101), of the electrode (20) or of the power supply wire (30).
  7. Discharge lamp having at least one electrode system according to one or more of Claims 1 to 6.
  8. Method for producing an electrode system for a discharge lamp, which comprises at least one metal foil (10), an electrode (20), which is connected to a first end (101) of the at least one metal foil (10), and a power supply wire (30), which is connected to a second end (102) of the at least one metal foil (10), at least the first (101) or second end (102) of the metal foil (10) being cut to size before the at least one metal foil (10) is connected to the electrode (20) and to the power supply wire (30) such that the at least one metal foil (10) has a reduced width at this end (101), and a section (21, 31) of the electrode (20) or of the power supply wire (30) being flattened for the purpose of connecting to the narrowed or tapered first end (101) or second end (102) of the at least one metal foil (10), characterized in that an edge of the flattened section (21, 31) of the electrode (20) or of the power supply wire (30) is provided with a bevel (22).
  9. Method according to Claim 8, characterized in that both the first (101) and the second ends (102) of the at least one metal foil (10) are cut to size such that the at least one metal foil (10) has a reduced width at both ends (101, 102).
  10. Method according to Claim 8 or 9, characterized in that the at least one metal foil (10) is cut to size such that the width of the at least one metal foil (10) continuously increases, starting from its first (101) or second end (102) in the direction of the metal foil center.
  11. Method according to Claim 8, characterized in that the free end of the section (21, 31) of the electrode (20) or of the power supply wire (30) is heated prior to being flattened and is shaped to form a dome.
  12. Method according to Claim 8, characterized in that the flattened section (21, 31) of the electrode (20) or of the power supply wire (30) is welded to the at least one metal foil (10).
EP04028991A 2003-12-22 2004-12-07 Elektrode system for discharge lamp, discharge lamp comprising such electrode system and method of fabrication of such an electrode system Not-in-force EP1548788B1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE10361105A DE10361105A1 (en) 2003-12-22 2003-12-22 Electrode system for a gas discharge lamp has an electrode to generate a gas discharge and a metal fusing/sealing foil linked to the electrode and to a wire supplying power to the electrode
DE10361105 2003-12-22
DE200410003041 DE102004003041A1 (en) 2004-01-20 2004-01-20 Electrode system for discharge lamp, has metallic foil in which width in both edge portions is reduced along longitudinal direction edge
DE4003041 2004-01-20

Publications (3)

Publication Number Publication Date
EP1548788A2 EP1548788A2 (en) 2005-06-29
EP1548788A3 EP1548788A3 (en) 2007-01-17
EP1548788B1 true EP1548788B1 (en) 2009-02-11

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EP04028991A Not-in-force EP1548788B1 (en) 2003-12-22 2004-12-07 Elektrode system for discharge lamp, discharge lamp comprising such electrode system and method of fabrication of such an electrode system

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EP (1) EP1548788B1 (en)
JP (1) JP2005183398A (en)
AT (1) ATE422706T1 (en)
DE (1) DE502004008963D1 (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102005013760A1 (en) * 2005-03-22 2006-09-28 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Method for producing an electrode and discharge lamp with such an electrode
WO2009106133A1 (en) * 2008-02-27 2009-09-03 Osram Gesellschaft mit beschränkter Haftung Melting film, method for the production thereof, and lamp having such a film
JP2017216146A (en) * 2016-05-31 2017-12-07 東芝ライテック株式会社 Long arc type ultraviolet lamp and irradiation device

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3868528A (en) 1974-01-14 1975-02-25 Gen Electric Quartz pinches containing sealant glass
US4136298A (en) 1977-08-15 1979-01-23 General Electric Company Electrode-inlead for miniature discharge lamps
US4254356A (en) 1979-04-23 1981-03-03 General Electric Company Inlead and method of making a discharge lamp
DE19724544A1 (en) 1997-06-11 1998-12-17 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Molybdenum foil sealing in glass and electric lamp with such a molybdenum foil sealing

Also Published As

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DE502004008963D1 (en) 2009-03-26
JP2005183398A (en) 2005-07-07
EP1548788A3 (en) 2007-01-17
EP1548788A2 (en) 2005-06-29
ATE422706T1 (en) 2009-02-15

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