EP1861862B1 - Method for producing an electrode and gas discharge lamp having an electrode of this type - Google Patents

Method for producing an electrode and gas discharge lamp having an electrode of this type Download PDF

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Publication number
EP1861862B1
EP1861862B1 EP06706032A EP06706032A EP1861862B1 EP 1861862 B1 EP1861862 B1 EP 1861862B1 EP 06706032 A EP06706032 A EP 06706032A EP 06706032 A EP06706032 A EP 06706032A EP 1861862 B1 EP1861862 B1 EP 1861862B1
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EP
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Prior art keywords
electrode
lamp
discharge
producing
discharge lamp
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EP06706032A
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German (de)
French (fr)
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EP1861862A1 (en
Inventor
Jürgen Becker
Jianping Liu
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Osram GmbH
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Osram GmbH
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    • 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
    • H01J9/245—Manufacture or joining of vessels, leading-in conductors or bases specially adapted for gas discharge tubes or lamps
    • H01J9/247—Manufacture or joining of vessels, leading-in conductors or bases specially adapted for gas discharge tubes or lamps specially adapted for gas-discharge lamps
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/02—Details
    • H01J61/04—Electrodes; Screens; Shields
    • H01J61/06—Main electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/02—Details
    • H01J61/04—Electrodes; Screens; Shields
    • H01J61/06—Main electrodes
    • H01J61/073—Main electrodes for high-pressure discharge lamps
    • 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
    • H01J9/02—Manufacture of electrodes or electrode systems

Definitions

  • the invention relates to a method for producing an electrode according to the preamble of patent claim 1.
  • Such electrodes provided with an electrode tip are used, for example, in discharge lamps.
  • the process for producing electrodes consists essentially of powder metallurgy production of an electrode blank, a sintering process and the subsequent mechanical deformation of the blank to the desired electrode diameter.
  • the forming of the blanks takes place for example by rolling on a multi-roll or by hammering on rotary hammers.
  • the diameter of the blank is reduced with simultaneous elongation of the material.
  • the billet diameter is further reduced from about 4 mm by a drawing process.
  • the applicant known to form the electrode tip by radial forming, for example by means of profiled hammers baking.
  • This solution enables a grain boundary structure following the contour of the electrode tip, since the electrode tip is not produced by mechanical or chemical removal.
  • a disadvantage of such electrodes is that the final microstructure and purity of the electrode tip is achieved only during operation of the lamp due to a recrystallization of the structure caused by the effect of the temperature of the gas discharge. That is, at the beginning of the operating life of such electrodes have a long-crystalline, fibrous microstructure, which lead to poor ignition properties and an unfavorable arch approach.
  • the EP 1 148 534 A1 discloses a rod-shaped electrode for a discharge lamp whose discharge-side end is covered with a coil. This helix is fused to the hemispherical end of the electrode.
  • the invention has for its object to provide a method for producing an electrode or power supply and a lamp with such an electrode or power supply, in which compared to conventional solutions improved performance is possible.
  • the microstructure of at least one section of the electrode is at least partially converted by means of high-energy radiation, preferably laser radiation. Due to the temperature effect of the high-energy radiation on this electrode section, the fibrous, long-crystalline structural regions combine to form compact, dense units-in other words-a defined recrystallization of the microstructure of the electrode segment takes place. This recrystallization causes a coarsely crystalline structure in the region of this elec trodenabitess. As a result, this electrode section has a microstructure and purity substantially corresponding to the operating state of the lamp.
  • the abovementioned electrode section preferably comprises the discharge-side end of the electrode.
  • the aforementioned microstructure of the discharge-side end of the electrode remains stable during operation of the lamp and it ensures good ignition properties and a good bow approach. This allows the electrode tip according to the invention opposite the prior art according to the EP 0 858 098 B1 already at the beginning of the life of the lamp an optimal ignition behavior and a good arc formation. Furthermore, a high purity of the electrode is achieved due to the influence of temperature.
  • the crystal structure is consistently converted.
  • a defined, coarse-grained microstructure surface of the electrode section is present.
  • the structure of at least a portion of the power supply by means of high-energy radiation, preferably laser radiation, at least partially converted for example, by means of the high-energy radiation, a surface portion of the power supply is treated, for example, to evaporate adhering to the surface impurities or to smooth the surface of the power supply or to convert the crystal structure of the power supply to its surface, thereby improving the so-called glazing behavior of the power supply, that is, to reduce the adhesion of the power supply to the surrounding glass of the lamp vessel and thus the risk of cracking in the lamp vessel due to different thermal expansion coefficients of glass and power supply material.
  • the power supply is preferably formed as a wire of molybdenum, tungsten or an alloy of molybdenum or tungsten.
  • a discharge lamp produced according to the invention has at least one electrode and at least one power supply, wherein the structure of at least a portion of the electrode or the power supply by means of high-energy radiation, preferably laser radiation, at least partially converted.
  • an electrode section has a structure substantially corresponding to the operating state of the discharge lamp.
  • this electrode section has a coarsely crystalline structure.
  • this electrode section has a purity substantially corresponding to the operating state of the lamp.
  • blackening in the discharge vessel is reduced to a minimum and the service life of the discharge lamp is substantially extended.
  • this electrode section is produced by means of high-energy radiation, preferably laser radiation.
  • the aforementioned electrode section is the discharge-side end of the electrode.
  • the invention is preferably applied to rod-shaped tungsten electrodes, in particular for high-pressure discharge lamps.
  • the lamp shown is a high-pressure discharge lamp 1, as used for example in vehicle headlights or projectors use.
  • This has a discharge vessel 2 made of quartz glass with an interior 4 and two diametrically arranged, sealed end sections 6, 8, which are formed as Glaseinschmelzonne 10, 12 and each having a power supply 14 which embedded with gas-tight in the Glaseinschmelzonne 10, 12 of the discharge lamp 1 , Be as rectangular molybdenum foils 16, 18 are welded.
  • In the interior 4 protrude two diametrically arranged, such as pin-shaped electrodes 20, 22 made of doped with ThO 2 tungsten, each with one of Molybdenum foils 16, 18 are welded and between which forms a gas discharge during lamp operation.
  • an ionizable filling which consists of high purity xenon gas and a plurality of metal halides.
  • the electrodes 20, 22 each have a first end portion 26 embedded in the glass melt 10 or 12 as the electrode shaft 24. At a second end portion 28, the electrodes 20, 22 are provided with an electrode tip 30.
  • the structure of the electrode tips 30 is at least partially converted by means of high-energy radiation.
  • the high-energy radiation is introduced into the electrode tips 30 by means of a laser. Due to the temperature effect of the laser radiation on the electrode tip 30, the fibrous, long-crystalline structural regions combine to form compact, dense units-in other words-a defined recrystallization of the microstructure of the electrode tip 30 takes place.
  • the recrystallization causes a relatively coarse-crystalline structure in the region of the electrode tip 30. As a result, this has a structure and purity substantially corresponding to the operating state of the discharge lamp 1.
  • This microstructure of the electrode tip 30 remains stable during operation of the lamp 1 and has good ignition properties and an advantageous bow approach.
  • the electrode tip 30 according to the invention allows over the prior art according to the EP 0 858 098 B1 Optimal ignition behavior and good arc formation already at the beginning of lamp life. Furthermore, due to the temperature effect of the laser radiation, a high purity of the electrodes 20, 22 is achieved.
  • FIG. 2 which shows an enlarged view of the electrode 20 FIG. 1 shows
  • the cylindrical electrode shaft 24 tapers frustoconically to the electrode tip 30, the conical surface 32 discharges discharge side in an approximately circular end face 34.
  • the electrode tip 30 is produced by means of the laser radiation during the structural transformation and has the in FIG. 1 explained microstructure.
  • An electrode 20, 22 produced according to the invention is not limited to the described shaping of the electrode tip 30 by laser radiation, but the electrode tip 30 can be formed by any known from the general state of the art forming technique, in particular by grinding, etching, hammering or the like in any geometric shapes be.
  • the discharge-side end 30 of the electrodes 20, 22 may also be thickened instead of pointed.
  • the structural transformation of the electrode section 30 according to the invention can take place before or after the welding of the electrode 20, 22 with the molybdenum foil 16, 18.
  • the structure of a portion of the electrodes by means of high-energy radiation, preferably laser radiation at least partially converted.

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

Description

Technisches GebietTechnical area

Die Erfindung betrifft ein Verfahren zur Herstellung einer Elektrode gemäß dem Oberbegriff des Patentanspruchs 1.The invention relates to a method for producing an electrode according to the preamble of patent claim 1.

Stand der TechnikState of the art

Derartige mit einer Elektrodenspitze versehene Elektroden finden beispielsweise in Entladungslampen Verwendung. Das Verfahren zur Elektrodenherstellung besteht im Wesentlichen aus der pulvermetallurgischen Herstellung eines Elektrodenrohlings, einem Sinterprozess und dem anschließenden mechanischen Umformen des Rohlings auf den gewünschten Elektrodendurchmesser. Das Umformen der Rohlinge erfolgt beispielsweise durch Walzen auf einer Mehrfachwalze oder durch Hämmern auf Rundhämmermaschinen. Hierbei wird der Durchmesser des Rohlings unter gleichzeitiger Längung des Materials reduziert. Für Elektroden mit kleinerem Durchmesser wird der Rohlingdurchmesser ab etwa 4 mm durch einen Ziehprozess weiter verringert. Es hat sich gezeigt, dass das Ziehen auf dünne Durchmesser eine längsgerichtete Faserstruktur und dadurch eine extreme Störung der Gefügestruktur innerhalb der Elektrode verursacht, da die Korngrenzenstrukturen parallel zur Längsachse des Rohlings verlaufen und zwar nicht nur im Bereich des Elektrodenschaftes sondern auch im Bereich der Elektrodenspitze. Nach dem Erzeugen der Elektrodenspitze durch aus dem allgemeinen Stand der Technik bekannte Formgebungsverfahren, wie beispielsweise durch Rundschleifen oder chemisches Abtragen mündet die Korngrenzenstruktur an der schrägen Fläche der Elektrodenspitze.Such electrodes provided with an electrode tip are used, for example, in discharge lamps. The process for producing electrodes consists essentially of powder metallurgy production of an electrode blank, a sintering process and the subsequent mechanical deformation of the blank to the desired electrode diameter. The forming of the blanks takes place for example by rolling on a multi-roll or by hammering on rotary hammers. In this case, the diameter of the blank is reduced with simultaneous elongation of the material. For smaller diameter electrodes, the billet diameter is further reduced from about 4 mm by a drawing process. It has been found that pulling on thin diameters causes a longitudinal fiber structure and thereby extreme disruption of the microstructure within the electrode, since the grain boundary structures are parallel to the longitudinal axis of the blank, not only in the area of the electrode shaft but also in the area of the electrode tip. After the electrode tip has been formed by shaping processes known from the general state of the art, such as for example by cylindrical grinding or chemical removal, the grain boundary structure terminates at the oblique surface of the electrode tip.

Zur Verbesserung der Korngrenzenstruktur im Bereich der Elektrodenspitze ist es aus der DE 197 38 574 A1 der Anmelderin bekannt, die Elektrodenspitze durch radiales Umformen, beispielsweise mittels profilierten Hämmerbacken auszubilden. Diese Lösung ermöglicht eine der Kontur der Elektrodenspitze folgende Korngrenzenstruktur, da die Elektrodenspitze nicht durch mechanisches oder chemisches Abtragen erzeugt wird. Nachteilig bei derartigen Elektroden ist, dass die endgültige Gefügestruktur und Reinheit der Elektrodenspitze erst beim Betrieb der Lampe aufgrund einer durch die Temperatureinwirkung der Gasentladung verursachten Rekristallisation des Gefüges erreicht wird. Das heißt, am Anfang der Betriebsdauer weisen derartige Elektroden eine langkristalline, faserartige Gefügestruktur auf, die zu schlechten Zündeigenschaften und einem ungünstigen Bogenansatz führen.To improve the grain boundary structure in the region of the electrode tip, it is from the DE 197 38 574 A1 the applicant known to form the electrode tip by radial forming, for example by means of profiled hammers baking. This solution enables a grain boundary structure following the contour of the electrode tip, since the electrode tip is not produced by mechanical or chemical removal. A disadvantage of such electrodes is that the final microstructure and purity of the electrode tip is achieved only during operation of the lamp due to a recrystallization of the structure caused by the effect of the temperature of the gas discharge. That is, at the beginning of the operating life of such electrodes have a long-crystalline, fibrous microstructure, which lead to poor ignition properties and an unfavorable arch approach.

Die EP 1 148 534 A1 offenbart eine stabförmige Elektrode für eine Entladungslampe, deren entladungsseitiges Ende mit einer Wendel überzogen ist. Diese Wendel ist mit dem halbkugelförmigen Elektrodenende verschmolzen.The EP 1 148 534 A1 discloses a rod-shaped electrode for a discharge lamp whose discharge-side end is covered with a coil. This helix is fused to the hemispherical end of the electrode.

Darstellung der ErfindungPresentation of the invention

Der Erfindung liegt die Aufgabe zugrunde, ein Verfahren zur Herstellung einer Elektrode bzw. Stromzuführung sowie eine Lampe mit einer derartigen Elektrode bzw. Stromzuführung zu schaffen, bei denen gegenüber herkömmlichen Lösungen ein verbessertes Betriebsverhalten ermöglicht ist.The invention has for its object to provide a method for producing an electrode or power supply and a lamp with such an electrode or power supply, in which compared to conventional solutions improved performance is possible.

Diese Aufgabe wird hinsichtlich des Verfahrens zur Herstellung einer Elektrode bzw. Stromzuführung durch die Merkmale des Anspruchs 1 gelöst. Eine besonders vorteilhafte Ausführung der Erfindung ist in demabhängigen Anspruch beschrieben.This object is achieved with regard to the method for producing an electrode or power supply by the features of claim 1. A particularly advantageous embodiment of the invention is described in the dependent claim.

Bei dem erfindungsgemäßen Verfahren zur Herstellung einer Elektrode, wird das Gefüge zumindest eines Abschnitts der Elektrode mittels hochenergetischer Strahlung, vorzugsweise Laserstrahlung, zumindest teilweise umgewandelt. Aufgrund der Temperatureinwirkung der hochenergetischen Strahlung auf diesen Elektrodenabschnitt vereinigen sich die faserförmigen, langkristallinen Gefügebereiche zu kompakten, dichten Einheiten - mit anderen Worten - eine definierte Rekristallisation des Gefüges des Elektrodenabschnitts findet statt. Diese Rekristallisation bewirkt ein grobkristallines Gefüge im Bereich dieses Elek-trodenabschnitts. Dadurch weist dieser Elektrodenabschnitt eine dem Betriebszustand der Lampe im Wesentlichen entsprechende Gefügestruktur und Reinheit auf Der vorgenannte Elektrodenabschnitt umfasst vorzugsweise das entladungsseitige Ende der Elektrode. Die vorgenannte Gefügestruktur des entladungsseitigen Endes der Elektrode bleibt dadurch im Betrieb der Lampe stabil und es werden gute Zündeigenschaften sowie ein guter Bogenansatz gewährleistet. Dadurch ermöglicht die erfindungsgemäße Elektrodenspitze gegenüber dem Stand der Technik gemäß der EP 0 858 098 B1 bereits am Anfang der Lebensdauer der Lampe ein optimales Zündverhalten und eine gute Lichtbogenausbildung. Weiterhin wird aufgrund der Temperatureinwirkung eine hohe Reinheit der Elektrode erreicht.In the method according to the invention for producing an electrode, the microstructure of at least one section of the electrode is at least partially converted by means of high-energy radiation, preferably laser radiation. Due to the temperature effect of the high-energy radiation on this electrode section, the fibrous, long-crystalline structural regions combine to form compact, dense units-in other words-a defined recrystallization of the microstructure of the electrode segment takes place. This recrystallization causes a coarsely crystalline structure in the region of this elec trodenabschnitts. As a result, this electrode section has a microstructure and purity substantially corresponding to the operating state of the lamp. The abovementioned electrode section preferably comprises the discharge-side end of the electrode. The aforementioned microstructure of the discharge-side end of the electrode remains stable during operation of the lamp and it ensures good ignition properties and a good bow approach. This allows the electrode tip according to the invention opposite the prior art according to the EP 0 858 098 B1 already at the beginning of the life of the lamp an optimal ignition behavior and a good arc formation. Furthermore, a high purity of the electrode is achieved due to the influence of temperature.

Vorzugsweise wird das Kristallgefüge durchgängig umgewandelt. Dadurch liegt auch nach längerem Betrieb der Entladungslampe eine definierte, grobkörnige Gefügeoberfläche des Elektrodenabschnitts vor.Preferably, the crystal structure is consistently converted. As a result, even after prolonged operation of the discharge lamp, a defined, coarse-grained microstructure surface of the electrode section is present.

Bei dem erfindungsgemäßen Verfahren zur Herstellung einer Stromzuführung, wird das Gefüge zumindest eines Abschnitts der Stromzuführung mittels hochenergetischer Strahlung, vorzugsweise Laserstrahlung, zumindest teilweise umgewandelt. Beispielsweise wird mittels der hochenergetischen Strahlung ein Oberflächenabschnitt der Stromzuführung behandelt, um zum Beispiel auf der Oberfläche haftende Verunreinigungen abzudampfen oder um die Oberfläche der Stromzuführung zu glätten oder um das Kristallgefüge der Stromzuführung an ihrer Oberfläche umzuwandeln und dadurch das so genannte Anglasungsverhalten der Stromzuführung zu verbessern, das heißt, die Haftung der Stromzuführung an dem sie umgebenden Glas des Lampengefäßes und somit die Gefahr der Rissbildung im Lampengefäß aufgrund unterschiedlicher thermischer Ausdehnungskoeffizienten von Glas- und Stromzuführungsmaterial zu verringern. Die Stromzuführung ist vorzugsweise als Draht aus Molybdän, Wolfram oder einer Legierung von Molybdän oder Wolfram ausgebildet.In the inventive method for producing a power supply, the structure of at least a portion of the power supply by means of high-energy radiation, preferably laser radiation, at least partially converted. For example, by means of the high-energy radiation, a surface portion of the power supply is treated, for example, to evaporate adhering to the surface impurities or to smooth the surface of the power supply or to convert the crystal structure of the power supply to its surface, thereby improving the so-called glazing behavior of the power supply, that is, to reduce the adhesion of the power supply to the surrounding glass of the lamp vessel and thus the risk of cracking in the lamp vessel due to different thermal expansion coefficients of glass and power supply material. The power supply is preferably formed as a wire of molybdenum, tungsten or an alloy of molybdenum or tungsten.

Eine erfindungsgemäß hergestellte Entladungslampe hat zumindest eine Elektrode und zumindest eine Stromzuführung, wobei das Gefüge zumindest eines Abschnitts der Elektrode bzw. der Stromzuführung mittels hochenergetischer Strahlung, vorzugsweise Laserstrahlung, zumindest teilweise umgewandelt ist.A discharge lamp produced according to the invention has at least one electrode and at least one power supply, wherein the structure of at least a portion of the electrode or the power supply by means of high-energy radiation, preferably laser radiation, at least partially converted.

Als besonders vorteilhaft hat es sich erwiesen, wenn ein Elektrodenabschnitt ein dem Betriebszustand der Entladungslampe im Wesentlichen entsprechendes Gefüge aufweist.It has proved to be particularly advantageous if an electrode section has a structure substantially corresponding to the operating state of the discharge lamp.

Gemäß dem Ausführungsbeispiel der Erfindung hat dieser Elektrodenabschnitt ein grobkristallines Gefüge.According to the embodiment of the invention, this electrode section has a coarsely crystalline structure.

Vorzugsweise hat dieser Elektrodenabschnitt eine dem Betriebszustand der Lampe im Wesentlichen entsprechende Reinheit. Dadurch werden Schwärzungen im Entladungsgefäß auf ein Minimum reduziert und die Lebensdauer der Entladungslampe wesentlich verlängert.Preferably, this electrode section has a purity substantially corresponding to the operating state of the lamp. As a result, blackening in the discharge vessel is reduced to a minimum and the service life of the discharge lamp is substantially extended.

Bei dem erfindungsgemäßen Ausführungsbeispiel ist dieser Elektrodenabschnitt mittels hochenergetischer Strahlung, vorzugsweise Laserstrahlung hergestellt.In the exemplary embodiment according to the invention, this electrode section is produced by means of high-energy radiation, preferably laser radiation.

Bei dem vorgenannten Elektrodenabschnitt handelt es sich um das entladungsseitige Ende der Elektrode. Die Erfindung wird vorzugsweise auf stabförmige Wolframelektroden, insbesondere für Hochdruckentladungslampen angewandt.The aforementioned electrode section is the discharge-side end of the electrode. The invention is preferably applied to rod-shaped tungsten electrodes, in particular for high-pressure discharge lamps.

Kurze Beschreibung der ZeichnungenBrief description of the drawings

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

Figur 1
eine schematische Darstellung einer erfindungsgemäß hergestellte Entladungslampe und
Figur 2
eine vergrößerte Darstellung einer Elektrode aus Figur 1.
The invention will be explained in more detail below with reference to a preferred embodiment. Show it:
FIG. 1
a schematic representation of a discharge lamp according to the invention and
FIG. 2
an enlarged view of an electrode FIG. 1 ,

Bevorzugte Ausführungen der ErfindungPreferred embodiments of the invention

Bei der in Figur 1 gezeigte Lampe handelt es sich um eine Hochdruckentladungslampe 1, wie sie beispielsweise in Fahrzeugscheinwerfern oder Projektoren Verwendung findet. Diese besitzt ein Entladungsgefäß 2 aus Quarzglas mit einem Innenraum 4 und zwei diametral angeordneten, abgedichteten Endabschnitten 6, 8, die als Glaseinschmelzungen 10, 12 ausgebildet sind und jeweils eine Stromzuführung 14 aufweisen, die mit gasdicht in den Glaseinschmelzungen 10, 12 der Entladungslampe 1 eingebetteten, etwa rechteckigen Molybdänfolien 16, 18 verschweißt sind. In den Innenraum 4 ragen zwei diametral angeordnete, etwa stiftförmige Elektroden 20, 22 aus mit ThO2 dotiertem Wolfram, die jeweils mit einer der Molybdänfolien 16, 18 verschweißt sind und zwischen denen sich während des Lampenbetriebs eine Gasentladung ausbildet. In dem Innenraum 4 des Entladungsgefäßes 2 ist eine ionisierbare Füllung eingeschlossen, die aus hochreinem Xenongas und mehreren Metallhalogeniden besteht. Die Elektroden 20, 22 haben jeweils einen in der Glaseinschmelzung 10 bzw. 12 eingebetteten als Elektrodenschaft 24 ausgebildeten ersten Endabschnitt 26. An einem zweiten Endabschnitt 28 sind die Elektroden 20, 22 mit einer Elektrodenspitze 30 versehen. Das Gefüge der Elektrodenspitzen 30 ist mittels hochenergetischer Strahlung zumindest teilweise umgewandelt. Bei dem Ausführungsbeispiel wird die hochenergetische Strahlung mittels Laser in die Elektrodenspitzen 30 eingebracht. Aufgrund der Temperatureinwirkung der Laserstrahlung auf der Elektrodenspitze 30 vereinigen sich die faserförmigen, langkristallinen Gefügebereiche zu kompakten, dichten Einheiten - mit anderen Worten - eine definierte Rekristallisation des Gefüges der Elektrodenspitze 30 findet statt. Die Rekristallisation bewirkt ein relativ grobkristallines Gefüge im Bereich der Elektrodenspitze 30. Dadurch weist diese eine dem Betriebszustand der Entladungslampe 1 im Wesentlichen entsprechende Gefügestruktur und Reinheit auf. Diese Gefügestruktur der Elektrodenspitze 30 bleibt im Betrieb der Lampe 1 stabil und hat gute Zündeigenschaften sowie einen vorteilhaften Bogenansatz. Die erfindungsgemäße Elektrodenspitze 30 ermöglicht gegenüber dem Stand der Technik gemäß der EP 0 858 098 B1 bereits am Anfang der Lampenlebensdauer ein optimales Zündverhalten und eine gute Lichtbogenausbildung. Weiterhin wird aufgrund der Temperatureinwirkung der Laserstrahlung eine hohe Reinheit der Elektroden 20, 22 erreicht.At the in FIG. 1 The lamp shown is a high-pressure discharge lamp 1, as used for example in vehicle headlights or projectors use. This has a discharge vessel 2 made of quartz glass with an interior 4 and two diametrically arranged, sealed end sections 6, 8, which are formed as Glaseinschmelzungen 10, 12 and each having a power supply 14 which embedded with gas-tight in the Glaseinschmelzungen 10, 12 of the discharge lamp 1 , Be as rectangular molybdenum foils 16, 18 are welded. In the interior 4 protrude two diametrically arranged, such as pin-shaped electrodes 20, 22 made of doped with ThO 2 tungsten, each with one of Molybdenum foils 16, 18 are welded and between which forms a gas discharge during lamp operation. In the interior 4 of the discharge vessel 2 an ionizable filling is included, which consists of high purity xenon gas and a plurality of metal halides. The electrodes 20, 22 each have a first end portion 26 embedded in the glass melt 10 or 12 as the electrode shaft 24. At a second end portion 28, the electrodes 20, 22 are provided with an electrode tip 30. The structure of the electrode tips 30 is at least partially converted by means of high-energy radiation. In the exemplary embodiment, the high-energy radiation is introduced into the electrode tips 30 by means of a laser. Due to the temperature effect of the laser radiation on the electrode tip 30, the fibrous, long-crystalline structural regions combine to form compact, dense units-in other words-a defined recrystallization of the microstructure of the electrode tip 30 takes place. The recrystallization causes a relatively coarse-crystalline structure in the region of the electrode tip 30. As a result, this has a structure and purity substantially corresponding to the operating state of the discharge lamp 1. This microstructure of the electrode tip 30 remains stable during operation of the lamp 1 and has good ignition properties and an advantageous bow approach. The electrode tip 30 according to the invention allows over the prior art according to the EP 0 858 098 B1 Optimal ignition behavior and good arc formation already at the beginning of lamp life. Furthermore, due to the temperature effect of the laser radiation, a high purity of the electrodes 20, 22 is achieved.

Gemäß Figur 2, die eine vergrößerte Darstellung der Elektrode 20 aus Figur 1 zeigt, verjüngt sich der zylindrische Elektrodenschaft 24 kegelstumpfförmig zu der Elektrodenspitze 30, deren Kegelmantelfläche 32 entladungsseitig in einer etwa kreisförmigen Stirnfläche 34 mündet. Dadurch wird ein guter Bogenansatz der Entladungslampe 1 erreicht. Die Elektrodenspitze 30 wird mittels der Laserstrahlung während der Gefügeumwandlung hergestellt und besitzt die in Figur 1 erläuterte Gefügestruktur.According to FIG. 2 , which shows an enlarged view of the electrode 20 FIG. 1 shows, the cylindrical electrode shaft 24 tapers frustoconically to the electrode tip 30, the conical surface 32 discharges discharge side in an approximately circular end face 34. As a result, a good arc projection of the discharge lamp 1 is achieved. The electrode tip 30 is produced by means of the laser radiation during the structural transformation and has the in FIG. 1 explained microstructure.

Eine erfindungsgemäß hergestellte Elektrode 20, 22 ist nicht auf die beschriebene Formgebung der Elektrodenspitze 30 durch Laserstrahlung beschränkt, vielmehr kann die Elektrodenspitze 30 mittels jeder aus dem allgemeinen Stand der Technik bekannten Umformtechnik, insbesondere durch Schleifen, Ätzen, Hämmern oder dergleichen in beliebigen geometrischen Formen ausgebildet sein. Außerdem kann das entladungsseitige Ende 30 der Elektroden 20, 22 auch verdickt anstatt zugespitzt ausgebildet sein. Weiterhin kann die erfindungsgemäße Gefügeumwandlung des Elektrodenabschnitts 30 vor oder nach dem Verschweißen der Elektrode 20, 22 mit der Molybdänfolie 16, 18 erfolgen.An electrode 20, 22 produced according to the invention is not limited to the described shaping of the electrode tip 30 by laser radiation, but the electrode tip 30 can be formed by any known from the general state of the art forming technique, in particular by grinding, etching, hammering or the like in any geometric shapes be. In addition, the discharge-side end 30 of the electrodes 20, 22 may also be thickened instead of pointed. Furthermore, the structural transformation of the electrode section 30 according to the invention can take place before or after the welding of the electrode 20, 22 with the molybdenum foil 16, 18.

Offenbart sind eine Lampe 1 mit zumindest einer Elektrode 20, 22, die einen Elektrodenschaft 24 und ein entladungsseitiges Elektrodenende 30 aufweist sowie ein Verfahren zur Herstellung einer derartigen Elektrode 20, 22. Erfindungsgemäß ist das Gefüge eines Abschnitts der Elektroden mittels hochenergetischer Strahlung, vorzugsweise Laserstrahlung zumindest teilweise umgewandelt.Disclosed are a lamp 1 with at least one electrode 20, 22, which has an electrode shaft 24 and a discharge-side electrode end 30 and a method for producing such an electrode 20, 22. According to the invention, the structure of a portion of the electrodes by means of high-energy radiation, preferably laser radiation at least partially converted.

BezugszeichenlisteLIST OF REFERENCE NUMBERS

11
Lampelamp
22
Entladungsgefäßdischarge vessel
44
Innenrauminner space
66
Endabschnittend
88th
Endabschnittend
1010
Glaseinschmelzungglass seal
1212
Glaseinschmelzungglass seal
1414
Stromzuführungpower supply
1616
Molybdänfoliemolybdenum foil
1818
Molybdänfoliemolybdenum foil
2020
Elektrodeelectrode
2222
Elektrodeelectrode
2424
Elektrodenschaftelectrode shaft
2626
Endabschnittend
2828
Endabschnittend
3030
Elektrodenspitzeelectrode tip
3232
KegelmantelflächeConical surface
3434
Stirnflächeface

Claims (2)

  1. Method for producing a rod-shaped electrode (20, 22) for a discharge lamp, characterized in that a fibrous, long-crystalline structure of the electrode (20, 22) is converted into a coarse-crystalline structure by means of high-energy radiation at least at the discharge-side end (30) of the electrode (20, 22).
  2. Method according to Claim 1, the high-energy radiation being laser radiation.
EP06706032A 2005-03-22 2006-03-21 Method for producing an electrode and gas discharge lamp having an electrode of this type Ceased EP1861862B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102005013760A DE102005013760A1 (en) 2005-03-22 2005-03-22 Method for producing an electrode and discharge lamp with such an electrode
PCT/DE2006/000496 WO2006099849A1 (en) 2005-03-22 2006-03-21 Method for producing an electrode and gas discharge lamp having an electrode of this type

Publications (2)

Publication Number Publication Date
EP1861862A1 EP1861862A1 (en) 2007-12-05
EP1861862B1 true EP1861862B1 (en) 2009-05-27

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP06706032A Ceased EP1861862B1 (en) 2005-03-22 2006-03-21 Method for producing an electrode and gas discharge lamp having an electrode of this type

Country Status (6)

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US (1) US20090015163A1 (en)
EP (1) EP1861862B1 (en)
JP (1) JP4918688B2 (en)
CN (1) CN101147225B (en)
DE (3) DE102005013760A1 (en)
WO (1) WO2006099849A1 (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5322217B2 (en) * 2008-12-27 2013-10-23 ウシオ電機株式会社 Light source device
JP2010205577A (en) * 2009-03-04 2010-09-16 Ushio Inc Method of lighting light source device
CN105304431B (en) * 2014-05-29 2017-06-13 深圳凯世光研股份有限公司 A kind of anode and its processing method, the short arc discharge lamp including the anode

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3300449A1 (en) * 1983-01-08 1984-07-12 Philips Patentverwaltung Gmbh, 2000 Hamburg METHOD FOR PRODUCING AN ELECTRODE FOR A HIGH PRESSURE GAS DISCHARGE LAMP
JPH05283039A (en) * 1992-03-31 1993-10-29 Toshiba Lighting & Technol Corp Metal vapor discharge lamp
DE9415217U1 (en) * 1994-09-21 1996-01-25 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH, 81543 München High pressure discharge lamp
US6705914B2 (en) * 2000-04-18 2004-03-16 Matsushita Electric Industrial Co., Ltd. Method of forming spherical electrode surface for high intensity discharge lamp
JP4846173B2 (en) * 2000-04-18 2011-12-28 パナソニック株式会社 High pressure discharge lamp and electrode for high pressure discharge lamp
DE10026567A1 (en) * 2000-05-30 2001-12-06 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Process for labeling quartz glass lamps and quartz glass lamps made therewith
JP2004079323A (en) * 2002-08-16 2004-03-11 Fuji Photo Film Co Ltd Manufacturing method for discharge tube
DE502004008963D1 (en) * 2003-12-22 2009-03-26 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Electrode system for a discharge lamp, discharge lamp with such an electrode system and method for producing such an electrode system

Also Published As

Publication number Publication date
EP1861862A1 (en) 2007-12-05
US20090015163A1 (en) 2009-01-15
WO2006099849A1 (en) 2006-09-28
CN101147225A (en) 2008-03-19
JP4918688B2 (en) 2012-04-18
DE112006001333A5 (en) 2008-03-06
JP2008533689A (en) 2008-08-21
DE102005013760A1 (en) 2006-09-28
CN101147225B (en) 2012-06-27
DE502006003811D1 (en) 2009-07-09

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