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WO2009109566A1 - Électrode en tungstène pour lampes à décharge haute pression et lampe à décharge haute pression comportant une électrode en tungstène - Google Patents

Électrode en tungstène pour lampes à décharge haute pression et lampe à décharge haute pression comportant une électrode en tungstène Download PDF

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Publication number
WO2009109566A1
WO2009109566A1 PCT/EP2009/052489 EP2009052489W WO2009109566A1 WO 2009109566 A1 WO2009109566 A1 WO 2009109566A1 EP 2009052489 W EP2009052489 W EP 2009052489W WO 2009109566 A1 WO2009109566 A1 WO 2009109566A1
Authority
WO
WIPO (PCT)
Prior art keywords
pressure discharge
tungsten electrode
weight
discharge lamp
tungsten
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.)
Ceased
Application number
PCT/EP2009/052489
Other languages
German (de)
English (en)
Inventor
Jürgen ALMANSTÖTTER
Rainer Himml
Ulrike Voigt
Frank Werner
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Osram GmbH
Original Assignee
Osram GmbH
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Osram GmbH filed Critical Osram GmbH
Publication of WO2009109566A1 publication Critical patent/WO2009109566A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • 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
    • H01J61/0735—Main electrodes for high-pressure discharge lamps characterised by the material of the electrode
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C27/00—Alloys based on rhenium or a refractory metal not mentioned in groups C22C14/00 or C22C16/00
    • C22C27/04—Alloys based on tungsten or molybdenum

Definitions

  • the invention relates to an electrode for high-pressure discharge lamps according to the preamble of claim 1 and to a high-pressure discharge lamp having at least one such electrode.
  • PRIOR ART EP 0 299 230 A1 discloses a cathode for high pressure discharge lamps consisting of a tungsten rod doped with thoria. The proportion of thorium oxide in the cathode material is 0.4 weight percent.
  • US 6,809,478 B2 discloses a high pressure metal halide discharge lamp for vehicular headlamps having tungsten electrodes containing not more than 0.4% by weight of thorium oxide.
  • the tungsten electrode for high-pressure discharge lamps according to the invention contains thorium oxide, in particular thorium 2008P04103EN01 -2-
  • the material of the tungsten electrode contains potassium at a weight fraction in the range of 0.003 weight percent to 0.009 weight percent.
  • the weight fraction of thorium oxide in the material of the tungsten electrode is less than 0.3 percent by weight, the thorium oxide or thorium no longer sufficiently contributes to an improvement in the emission of the electrode of the high-pressure discharge lamp.
  • a weight proportion of potassium of greater than or equal to 0.003 percent by weight ensures stabilization of the crystal structure in the tungsten electrode in the tungsten electrode according to the invention. With the help of potassium, stable tungsten crystals with a long-crystalline structure are formed during the drawing process and the annealing of the tungsten electrode during their production. If the proportion of potassium is reduced below the above-mentioned value of 0.003 percent by weight, an increased re-firing of the tungsten electrode occurs during lamp operation. On the other hand, if the potassium content in the tungsten electrode is increased to values above 0.009 percent by weight, strong potassium bubble growth occurs in the tungsten electrode, which causes the tungsten electrode to become brittle.
  • the weight fraction of all dopants and additives as well as impurities in the material of the tungsten electrode is less than or equal to 1.0 percent by weight so as not to reduce the melting temperature of the tungsten electrode.
  • the proportion of contamination of the electrode material with aluminum in the tungsten electrode is advantageously less than 0.0001 percent by weight in order to ensure a high breaking strength of the tungsten electrode.
  • the proportion of other impurities in the electrode material is advantageously less than or equal to 0.003 percent by weight.
  • the tungsten electrode according to the invention is formed as a tungsten rod, tungsten pin or section of a tungsten wire.
  • the electrode according to the invention is preferably used as a gas discharge electrode in high-pressure discharge lamps such as, for example, metal halide high-pressure discharge lamps.
  • FIG. 1 shows a comparison of the decrease in the luminous flux as a function of the operating time of the lamps for high-pressure discharge lamps according to the invention and conventional high-pressure discharge lamps.
  • the operating time of the lamps is in hours and on the vertical axis the luminous flux is shown as a percentage of the initial luminous flux of the lamps.
  • Measurement curve 1 shows the percentage decrease of the luminous flux as a function of the operating time of the lamp for high-pressure discharge lamps according to the invention
  • the measurement curve 2 shows the percentage decrease of the luminous flux as a function of the operating time of the lamp for conventional high-pressure discharge lamps.
  • the inventive and conventional high-pressure discharge lamps on which the measurement is based are each metal halide high-pressure discharge lamps for vehicle headlights as shown in FIG. 1.
  • inventive metal halide high-pressure discharge lamps on which the measurement curve 1 of FIG. 1 is based have tungsten electrodes with a composition according to FIG Table 2, while the measured curve 2 thorouggested in Figure 1 conventional halogen-metal vapor high-pressure discharge lamps 2008P04103EN01 -5-
  • FIG. 1 A comparison of the dependence of luminous flux intensity on the operating time of the lamp for high-pressure discharge lamps according to the invention and conventional high-pressure discharge lamps
  • FIG. 2 shows a side view of a high-pressure discharge lamp according to the invention
  • the preferred exemplary embodiment of the high-pressure discharge lamp according to the invention shown schematically in FIG. 2 is a mercury-free metal halide high-pressure discharge lamp with an electrical power consumption of 35 watts. This lamp is intended for use in a vehicle headlight. 2008P04103EN01 -6-
  • the discharge vessel 10 has a two-sided sealed discharge vessel 10 made of quartz glass with a volume of 24.5 mm, in which an ionizable filling is enclosed gas-tight.
  • the inner contour of the discharge vessel 10 is circular-cylindrical and its outer contour is ellipsoidal.
  • the inner diameter of the discharge space 106 is 2.6 mm and its outer diameter is 6.5 mm.
  • the two ends 101, 102 of the discharge vessel 10 are each sealed by means of a Molybdänfo- lien-meltdown 103, 104.
  • the molybdenum foils 103, 104 each have a length of 6.5 mm, a width of 2 mm and a thickness of 25 microns.
  • the electrodes 11, 12 are made of thoriated tungsten, that is, tungsten doped with thorium dioxide (ThO 2 ).
  • the additives and impurities in the tungsten electrodes 11, 12 are given in Tables 1 and 2 below for two preferred embodiments of the invention.
  • the thickness or the diameter of the electrodes 11, 12 is 0.33 mm.
  • the length of the electrodes 11, 12 is 7.5 mm in each case.
  • the distance between the electrodes 11, 12 is 4.1 mm.
  • the electrodes 11, 12 are in each case electrically conductively connected to one of the molybdenum foil melts 103, 104 and via the base-remote power supply 13 and the current return 17 or via the socket-side power supply 14 to an electrical connection of the lamp base 15 which consists essentially of plastic.
  • the molybdenum foil 103 attached thereto is 1.3 mm ⁇ 0.15 mm.
  • Table 1 Compilation of the additives and impurities in the tungsten electrodes according to the first embodiment of the invention
  • the proportions by weight of the additives and impurities were determined by means of the so-called GDMS analysis.
  • the abbreviation GDMS stands for Glow Discharge Mass Spectrometry.
  • Table 2 Composition of the additives and impurities in the tungsten electrodes according to the second embodiment of the invention
  • GDMS Glow Discharge Mass Spectrometry. 2008P04103EN01 -8-
  • the smallest distance of the molybdenum foil 103 to the end of the electrode 11 protruding into the interior of the discharge vessel 10 is 6.2 mm ⁇ 0.15 mm. That is, the distance of the molybdenum foil 103 to the discharge arc forming in the discharge vessel 10 during lamp operation is 6.2 mm ⁇ 0.15 mm.
  • An analogous statement also applies to the molybdenum foil 104 and the electrode 12. Details on this are disclosed in WO 2005/112074.
  • the discharge vessel 10 is enveloped by a glass outer bulb 16.
  • the outer bulb 16 has an extension 161 anchored in the base 15.
  • the discharge vessel 10 has a tube-like extension 105 made of quartz glass on the base side, in which the base-side current supply 14 extends.
  • the current return 17 facing surface region of the discharge vessel 10 is provided with a transparent, electrically conductive coating 107.
  • This coating 107 extends in the longitudinal direction of the lamp over the entire length of the discharge space 106 and over a part, about 50 percent, of the length of the sealed ends 101, 102 of the discharge vessel 10.
  • the coating 107 is mounted on the outside of the discharge vessel 10 and extends over about 5 percent to 10 percent of the circumference of the discharge vessel 10.
  • the coating 107 may also extend over 50 percent of the circumference of the discharge vessel 10 or even more than 50 percent of the circumference of the discharge vessel 10.
  • Such a wide version of the coating 107 has the advantage that it increases the efficiency of the high-pressure discharge lamp, since it is a part of the 2008P04103EN01 -9-
  • the coating 107 consists of doped tin oxide, for example of tin oxide doped with fluorine or antimony or, for example, boron and / or lithium doped tin oxide.
  • This high-pressure discharge lamp is operated in a horizontal position, that is, with arranged in a horizontal plane electrodes 11, 12, wherein the lamp is oriented such that the current return path 17 extends below the discharge vessel 30 and the outer bulb 16. Details of this coating 107 acting as an ignition aid are described in EP 1 632 985 A1.
  • the outer bulb 16 is made of quartz glass doped with ultraviolet ray absorbing materials such as cerium oxide and titanium oxide. Suitable glass compositions for the outer bulb glass are disclosed in EP 0 700 579 B1.
  • an ionizable filling contains xenon with a cold fill pressure, that is, a space at a temperature of 22 0 C measured filling pressure of 1.6 megapascals, 0.23 mg Natriumj iodide, 0.165 mg Scandiumj iodide, 0.05 mg Zinc iodide and 0.001 mg indium-iodide.
  • the burning voltage of the lamp is approx. 43 Volt. Its color temperature is slightly above 4000 Kelvin. If the iodide components of the filling are converted to 1 mm 3 of the discharge vessel volume, the result is 2008P04103EN01 -10-
  • the color rendering index of the metal halide high pressure discharge lamp is 65 and its luminous efficacy is 90 lm / W.
  • the wall load is about 80 W / cm 2 .
  • the high-pressure metal halide high-pressure discharge lamp according to the invention is operated immediately after ignition of the gas discharge in the discharge vessel at three to five times its rated power or rated current in order to ensure rapid vaporization of the metal halides in the ionizable filling. Immediately after the ignition of the gas discharge, it is almost exclusively carried by the xenon, since only the xenon is present in gaseous form in the discharge vessel at this time.
  • the high-pressure discharge lamp operates at this time and during the so-called start-up phase, during which the metal halides of the ionizable filling in the vapor phase, so like a high-pressure xenon discharge lamp, in which both the light emission and the electrical properties of the discharge, in particular the voltage drop above the discharge path, to be determined solely by the xenon. Only when the above-mentioned iodides of the ionizable filling are evaporated and they participate in the discharge, a quasi-stationary operating state of the lamp is reached, in which the lamp with 2008P04103EN01 - 11-
  • burning voltage therefore refers to the operating voltage of the high-pressure discharge lamp in quasi-stationary operation.
  • the invention is not limited to the embodiment explained in more detail above.
  • the electrodes 11, 12 can be used for example in metal halide high-pressure discharge lamps with mercury-containing filling containing xenon, sodium iodide and Scandiumj odid and mercury as filling.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Discharge Lamp (AREA)

Abstract

L'invention concerne des électrodes en tungstène conçues pour des lampes à décharge haute pression et contenant de l'oxyde de thorium selon une proportion en poids d'oxyde de thorium dans la matière de l'électrode en tungstène (11, 12) d'environ 0,3% en poids à 0,5% en poids, les électrodes en tungstène (11, 12) contenant de plus du potassium selon une proportion en poids d'environ 0,003% en poids à 0,009% en poids. L'invention concerne également des lampes à décharge haute pression possédant ce type d'électrodes.
PCT/EP2009/052489 2008-03-05 2009-03-03 Électrode en tungstène pour lampes à décharge haute pression et lampe à décharge haute pression comportant une électrode en tungstène Ceased WO2009109566A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE102008012583.0 2008-03-05
DE102008012583 2008-03-05
DE102008014096A DE102008014096A1 (de) 2008-03-05 2008-03-13 Wolframelektrode für Hochdruckentladungslampen und Hochdruckentladungslampe mit einer Wolframelektrode
DE102008014096.1 2008-03-13

Publications (1)

Publication Number Publication Date
WO2009109566A1 true WO2009109566A1 (fr) 2009-09-11

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PCT/EP2009/052489 Ceased WO2009109566A1 (fr) 2008-03-05 2009-03-03 Électrode en tungstène pour lampes à décharge haute pression et lampe à décharge haute pression comportant une électrode en tungstène

Country Status (2)

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DE (1) DE102008014096A1 (fr)
WO (1) WO2009109566A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20250223674A1 (en) * 2022-04-15 2025-07-10 A.L.M.T. Corp. Tungsten-containing material and direct current discharge lamp electrode

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE9415217U1 (de) * 1994-09-21 1996-01-25 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH, 81543 München Hochdruckentladungslampe
DE102005049239A1 (de) * 2004-10-14 2006-04-20 Koito Manufacturing Co., Ltd. Lichtbogenröhre für eine Entladungslampe
JP2006286236A (ja) * 2005-03-31 2006-10-19 Ushio Inc 高負荷高輝度放電ランプ
WO2007004663A1 (fr) * 2005-07-05 2007-01-11 Harison Toshiba Lighting Corporation Lampe à halogénure métallique et illuminateur l’employant
EP1768165A2 (fr) * 2005-09-22 2007-03-28 Toshiba Lighting & Technology Corporation Lampe à décharge haute pression exempte de mercure et luminaire
EP1801247A1 (fr) * 2005-12-23 2007-06-27 Plansee Metall GmbH Procédé de production des prodiuts finis ou semi-finis à haute densite

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3723271A1 (de) 1987-07-14 1989-01-26 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Kathode fuer eine hochdruckentladungslampe
DE4317369A1 (de) 1993-05-25 1994-12-01 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Hochdruckentladungslampe und Herstellungsverfahren für eine Hochdruckentladungslampe
JP3759498B2 (ja) 2001-03-30 2006-03-22 松下電器産業株式会社 自動車前照灯用メタルハライドランプ
DE102004024063A1 (de) 2004-05-13 2005-12-01 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Hochdruckentladungslampe
EP1632985B1 (fr) 2004-09-07 2014-06-25 OSRAM GmbH Lampe à decharge haute pression

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE9415217U1 (de) * 1994-09-21 1996-01-25 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH, 81543 München Hochdruckentladungslampe
DE102005049239A1 (de) * 2004-10-14 2006-04-20 Koito Manufacturing Co., Ltd. Lichtbogenröhre für eine Entladungslampe
JP2006286236A (ja) * 2005-03-31 2006-10-19 Ushio Inc 高負荷高輝度放電ランプ
WO2007004663A1 (fr) * 2005-07-05 2007-01-11 Harison Toshiba Lighting Corporation Lampe à halogénure métallique et illuminateur l’employant
EP1901333A1 (fr) * 2005-07-05 2008-03-19 Harison Toshiba Lighting Corporation Lampe a halogenure metallique et illuminateur l' employant
EP1768165A2 (fr) * 2005-09-22 2007-03-28 Toshiba Lighting & Technology Corporation Lampe à décharge haute pression exempte de mercure et luminaire
EP1801247A1 (fr) * 2005-12-23 2007-06-27 Plansee Metall GmbH Procédé de production des prodiuts finis ou semi-finis à haute densite

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20250223674A1 (en) * 2022-04-15 2025-07-10 A.L.M.T. Corp. Tungsten-containing material and direct current discharge lamp electrode
US12460281B2 (en) * 2022-04-15 2025-11-04 A.L.M.T. Corp. Tungsten-containing material and direct current discharge lamp electrode

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