WO2009147041A2 - Lampe à décharge à haute pression sans thorium pour un mode de fonctionnement haute fréquence - Google Patents

Lampe à décharge à haute pression sans thorium pour un mode de fonctionnement haute fréquence Download PDF

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Publication number
WO2009147041A2
WO2009147041A2 PCT/EP2009/056450 EP2009056450W WO2009147041A2 WO 2009147041 A2 WO2009147041 A2 WO 2009147041A2 EP 2009056450 W EP2009056450 W EP 2009056450W WO 2009147041 A2 WO2009147041 A2 WO 2009147041A2
Authority
WO
WIPO (PCT)
Prior art keywords
lamp
pressure discharge
discharge lamp
free
thorium
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/EP2009/056450
Other languages
German (de)
English (en)
Other versions
WO2009147041A3 (fr
Inventor
Bernhard Siessegger
Grigorios Tsilimis
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 WO2009147041A2 publication Critical patent/WO2009147041A2/fr
Publication of WO2009147041A3 publication Critical patent/WO2009147041A3/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
    • H01J61/0737—Main electrodes for high-pressure discharge lamps characterised by the material of the electrode characterised by the electron emissive material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/02—Details
    • H01J61/56—One or more circuit elements structurally associated with the lamp

Definitions

  • the present invention relates to a high-pressure discharge lamp whose electrodes consist of a thorium-free material, and to a lamp arrangement having such a high-pressure discharge lamp and a ballast operating this high-pressure discharge lamp, and a method for operating such a high-pressure discharge lamp.
  • the high-pressure discharge lamps known from the prior art have a discharge vessel filled with a filling gas into which two electrodes extend, between which a gas discharge arc arises during operation.
  • gas discharge lamps are used in particular in motor vehicles, mercury-xenon high-pressure gas discharge lamps usually being used.
  • thorium can be mixed conces- Th ⁇ 2 as the electrode material (typically 0.7 to 1% Th ⁇ 2), whereby the thorium proportion is reduced, or the metal halide used as the filling can be mixed with THJ 4, whereby pure tungsten electrodes may be used. Although this reduces the total amount of thorium in the lamp, but still creates no thorium-free lamp. Such a lamp is described for example in the document WO2004105082.
  • thorium-free lamps are actually known from the prior art, for example, the publication US2005077828 proposes an electrode which has a two-stage design.
  • the electrode has a head part and a shaft part which are made of different materials and preferably of different diameters.
  • such constructed electrodes are thermally resilient, however, their production is extremely complicated and expensive, whereby the entire lamp is disproportionately expensive.
  • the document WO2007026288 also deals with the problem of providing a thorium-free lamp, in which case the problem of electromagnetic interference should additionally be reduced.
  • This object is achieved by a high-pressure discharge lamp which has a thorium-free electrode and is designed to be operated on a high-frequency ballast.
  • the ballast which is advantageously designed as an electronic ballast, includes an ignition unit and a converter unit.
  • the ignition unit generates the ignition voltage required for igniting the gas discharge in the high-pressure discharge lamp
  • the converter unit provides the lamp current required for proper lamp operation after ignition of the gas discharge.
  • the high-pressure discharge lamp according to the invention can influence its ignitability.
  • the high-pressure discharge lamp according to the invention is therefore equipped with an ignition aid for improving the ignitability.
  • an ignition aid for example, a third electrode, a so-called ignition electrode, serve over the ignition of the gas discharge is initiated in the high-pressure discharge lamp.
  • an electrical connection between the ignition electrode and a designated Output of an ignition unit made.
  • the ignition electrode protrudes into the discharge space.
  • the ignition electrode is separated from the discharge space at least through the wall of the discharge vessel.
  • an electrically conductive coating which covers parts of the surface of the discharge vessel and does not necessarily have to have an electrical connection to an output of the ignition unit can be sufficient as a starting aid.
  • the operating frequency is above 400 Hz, in particular above 1 MHz.
  • ballast is additionally designed for the operation of mercury-free high-pressure discharge lamps or is a universal ballast which can operate both mercury-containing and mercury-free discharge lamps. Further advantages and advantageous embodiments are defined in the subclaims.
  • FIG. 1 shows a schematic longitudinal section through a discharge vessel of a high-pressure discharge lamp
  • FIGS. 2a and 2b show a comparison of the luminance distribution of a mercury-free lamp in high-frequency operation and in low-frequency rectangular operation;
  • FIG. 4 is a side view of a high-pressure discharge lamp according to the invention in a schematic representation with the discharge vessel shown in FIG.
  • FIG. 1 shows a schematic representation of a longitudinal section through a high-pressure discharge lamp with a discharge vessel 1, which is made of quartz glass and in which a filling 10 is enclosed gas-tight. This closure takes place through pinch areas 2 and 3, in which electrodes 4 and 5 are embedded in such a way that their one end projects into the interior 10 of the discharge vessel 1.
  • the electrodes 4 and 5 are conductively connected via molybdenum foil seals 6 and 7 to power supply lines 8 and 9, which are connected to a lamp base 15, which preferably includes a ballast connected.
  • lamp base and ballast can also be formed separately from one another.
  • a gas discharge is ignited and maintained via an applied voltage between the electrodes 4 and 5, which is formed as an arc 11. This arc 11 is due to the thermal buoyancy largely above an imaginary line connecting the electrodes when the lamp is operated in a horizontal position.
  • FIG 4 shows a schematic representation of the complete structure of the high-pressure discharge lamp with the discharge vessel shown in Figure 1.
  • This preferred embodiment of the invention is a thorium-free and 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. It has a two-sided sealed discharge vessel 1 made of quartz glass with a volume of about 23 mm 3 , in which an ionizable filling is enclosed gas-tight.
  • the inner contour of the discharge vessel 1 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 2, 3 of the discharge vessel 1 are each sealed by means of a molybdenum foil sealing 6, 7.
  • the molybdenum foils 6, 7 each have a length of 6.5 mm, a width of 2 mm and a thickness of 25 microns.
  • the electrodes 4, 5 are each formed in one piece and consist of tungsten material, in particular of thorium-free tungsten material. Their thickness or their diameter is 0.30 mm.
  • the length of the electrodes 4, 5 is 7.5 mm in each case.
  • the distance between the electrodes 4, 5 is 4.1 mm.
  • the electrodes 4, 5 are in each case electrically conductively connected to one of the molybdenum foil melts 6, 7 and via the socket-remote power supply 8 and the current return 17 or via the socket-side power supply 9 to an electrical connection of the lamp base 15 which essentially consists of plastic - the.
  • the overlap between the electrode 4 and the molybdenum foil 6 connected thereto is 1.3 mm ⁇ 0.15 mm.
  • the smallest distance between the molybdenum foil 6 and the end of the electrode 4 projecting into the interior 10 of the discharge vessel 1 is 6.2 mm ⁇ 0.15 mm. That is, the distance of the molybdenum foil 6 to the discharge arc forming in the discharge vessel 1 during lamp operation is 6.2 mm ⁇ 0.15 mm.
  • the discharge vessel 1 is surrounded by a glass outer bulb 16.
  • the outer bulb 16 has an extension 161 anchored in the base 15.
  • the discharge vessel 1 has on the side a tubular extension 105 made of quartz glass, in which the socket-side power supply 9 extends.
  • the current return 17 facing surface region of the discharge vessel 1 is provided with a translucent, provided electrically conductive coating 107, which serves as a starting aid.
  • 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 2, 3 of the discharge vessel 1.
  • the coating 107 is mounted on the outside of the discharge vessel 1 and extends over about 5 percent to 10 percent of the circumference of the discharge vessel 1.
  • the coating 107 may also extend over 50 percent of the circumference of the discharge vessel 10 or even over more than 50 percent of the circumference of the discharge vessel 10.
  • Such a wide configuration of the coating 107 has the advantage of increasing the efficiency of the high pressure discharge lamp, as it reflects a portion of the infrared radiation generated by the discharge back into the discharge vessel and thereby for selective heating of the colder areas below the electrodes during lamp operation of the discharge vessel 1, in which the metal halides of the ionizable filling collect.
  • 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 4, 5, wherein the lamp is oriented such that the current return path 17 extends below the discharge vessel 1 and the outer bulb 16.
  • This coating 107 which acts as an ignition aid, are described in EP 1 632 985 A1.
  • the outer bulb 16 is made of quartz glass doped with substances absorbing ultraviolet rays is such as ceria and titania. Suitable glass compositions for the outer bulb glass are disclosed in EP 0 700 579 B1.
  • Burning voltage of the lamp is about 43 volts. Its color temperature is slightly above 4000 Kelvin.
  • FIGS. 2a and 2b show an arc 11 of such a mercury-free high-pressure gas discharge lamp, wherein it can clearly be seen that so-called focal spots 12 form at the transition areas between the electrodes 4, 5 and the discharge arc 11, forming the hottest and brightest points of the discharge arc.
  • FIG. 2 a shows a luminance distribution of a mercury-free lamp in high-frequency operation.
  • the temporal course of the lamp current is approximately sinusoidal with a fundamental frequency of 1.8 MHz.
  • FIG. 2b shows a luminance distribution of the arc of a mercury-free lamp in the case of low-frequency rectangular operation. In this case, the time profile of the lamp current has an approximately rectangular shape with a fundamental frequency of 400 Hz.
  • the lamp shows a rectangular operation significantly greater arc bending and less diffuse than in high frequency operation.
  • the arc attachment point is strongly contracted at the electrode, so that due to the reduced contact area ⁇ between the arc attachment point and electrode, the heat input of the resulting plasma by the arc is greatly reduced to the electrode tip. As a result, the total electrode temperature is also significantly reduced, as can also be seen in FIG.
  • Figure 3 shows a graph of the course of the electrode temperature as a function of the distance from the electrode. The distance is indicated on the horizontal axis in any arbitrary unit.
  • the graph provided with the reference numeral 14 shows a temperature profile of the electrode in the rectangular operation, while the graph marked 16 the course of Electrode temperature with high frequency operation shows. It can clearly be seen that instead of the almost 2400 Kelvin, which usually prevail at the tip of the electrode, only about 1900 Kelvin are achieved under high-frequency operation, whereby the thermal load of the electrodes is significantly reduced. As a result, the use of pure tungsten as electrode material is possible without any fear of over-melting of the electrode tips.
  • a high-pressure discharge lamp with a thorium-free material electrode which is designed to be operated on a high-frequency ballast, a method for operating the same, and a lamp arrangement with such a high-pressure discharge lamp and a ballast which is operated at high frequency.

Landscapes

  • Discharge Lamp (AREA)

Abstract

Lampe à décharge sans thorium ni mercure pour un mode de fonctionnement haute fréquence. L’invention concerne une lampe à décharge haute pression, comprenant une électrode (4, 5) constituée d'un matériau dépourvu de thorium, et conçue pour fonctionner avec un ballast haute fréquence. L’invention concerne également un procédé pour faire fonctionner cette lampe ainsi qu’un agencement de lampe équipé d’une telle lampe à décharge haute pression et d’un ballast qui fonctionne à haute fréquence.
PCT/EP2009/056450 2008-06-03 2009-05-27 Lampe à décharge à haute pression sans thorium pour un mode de fonctionnement haute fréquence Ceased WO2009147041A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE200810026521 DE102008026521A1 (de) 2008-06-03 2008-06-03 Thoriumfreie Hochdruckentladungslampe für Hochfrequenzbetrieb
DE102008026521.7 2008-06-03

Publications (2)

Publication Number Publication Date
WO2009147041A2 true WO2009147041A2 (fr) 2009-12-10
WO2009147041A3 WO2009147041A3 (fr) 2010-03-11

Family

ID=41268238

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2009/056450 Ceased WO2009147041A2 (fr) 2008-06-03 2009-05-27 Lampe à décharge à haute pression sans thorium pour un mode de fonctionnement haute fréquence

Country Status (2)

Country Link
DE (1) DE102008026521A1 (fr)
WO (1) WO2009147041A2 (fr)

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4317369A1 (de) 1993-05-25 1994-12-01 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Hochdruckentladungslampe und Herstellungsverfahren für eine Hochdruckentladungslampe
DE10200009A1 (de) * 2002-01-02 2003-07-17 Philips Intellectual Property Entladungslampe
EP1649492A2 (fr) 2003-05-26 2006-04-26 Philips Intellectual Property & Standards GmbH Electrode depourvue de thorium, presentant une meilleure stabilite de la couleur
US7583030B2 (en) * 2003-07-21 2009-09-01 Advanced Lighting Technologies, Inc. Dopant-free tungsten electrodes in metal halide lamps
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
WO2007026288A2 (fr) 2005-09-02 2007-03-08 Philips Intellectual Property & Standards Gmbh Lampe a decharge gazeuse haute pression

Also Published As

Publication number Publication date
WO2009147041A3 (fr) 2010-03-11
DE102008026521A1 (de) 2009-12-10

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