EP0484117A2 - Wärmesenke für Metallhalogenidlampe - Google Patents

Wärmesenke für Metallhalogenidlampe Download PDF

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Publication number
EP0484117A2
EP0484117A2 EP91310000A EP91310000A EP0484117A2 EP 0484117 A2 EP0484117 A2 EP 0484117A2 EP 91310000 A EP91310000 A EP 91310000A EP 91310000 A EP91310000 A EP 91310000A EP 0484117 A2 EP0484117 A2 EP 0484117A2
Authority
EP
European Patent Office
Prior art keywords
arc tube
lamp
heat sink
reflector
metal halide
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.)
Withdrawn
Application number
EP91310000A
Other languages
English (en)
French (fr)
Other versions
EP0484117A3 (en
Inventor
Timothy Peter Dever
John Martin Davenport
Gary Robert Allen
Gerald Edward Duffy
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.)
General Electric Co
Original Assignee
General Electric Co
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 General Electric Co filed Critical General Electric Co
Publication of EP0484117A2 publication Critical patent/EP0484117A2/de
Publication of EP0484117A3 publication Critical patent/EP0484117A3/en
Withdrawn legal-status Critical Current

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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00Gas-discharge or vapour-discharge lamps
    • H01J61/02Details
    • H01J61/52Cooling arrangements; Heating arrangements; Means for circulating gas or vapour within the discharge space
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21LIGHTING
    • F21SNON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S41/00Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps
    • F21S41/10Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps characterised by the light source
    • F21S41/14Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps characterised by the light source characterised by the type of light source
    • F21S41/17Discharge light sources
    • F21S41/172High-intensity discharge light sources
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21LIGHTING
    • F21SNON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S45/00Arrangements within vehicle lighting devices specially adapted for vehicle exteriors, for purposes other than emission or distribution of light
    • F21S45/40Cooling of lighting devices
    • F21S45/47Passive cooling, e.g. using fins, thermal conductive elements or openings

Definitions

  • This invention relates generally to means enabling improved light output from a metal halide discharge lamp and more particularly to achieving the improvement with heat sink means which regulate mercury condensation within the lamp arc tube in a distinctive manner.
  • Various metal halide discharge lamps commonly employ a fused quartz arc tube as the light source by reason of the refractory nature and optical transparency of this ceramic material.
  • the arc tube generally comprises a sealed envelope formed with fused quartz tubing with discharge electrodes being hermetically sealed therein.
  • a typical arc tube construction hermetically seals a pair of discharge electrodes at opposite ends of the sealed envelope although it is also known to have both electrodes being sealed at the same end of the arc tube.
  • the sealed arc tube further contains a fill of various metal substances which become vaporized during the discharge operation.
  • the fill includes mercury, sodium and metal halides along with one or more inert gases such as krypton, argon and xenon. Operation of such metal vapor discharge lamps can be carried out with various already known lamp ballast circuits employing either alternating current or direct current power sources.
  • Improved discharge electrode means are disclosed in the above referenced application (Attorney Docket LD10,104) to minimize occurrence of a light hole during lamp start and restart.
  • a particular combination of anode and cathode means is therein disclosed significantly reducing the rate and maximum accumulation of mercury condensate on the arc tube walls during lamp start-up.
  • Such improvement results from thermally managing mercury condensation during lamp cool-down so that condensation takes place adjacent the electrode means. More mercury is caused to condense at the anode end of the arc tube than condenses at the cathode end of the arc tube.
  • Subsequent vaporization of condensed mercury from the anode means is also retarded during lamp restart.
  • the cathode means have a dissimilar structural configuration relative to the anode means so as to exhibit a more rapid heating rate than the anode means during lamp start-up while further exhibiting a less rapid cooling rate than the anode means during lamp cool-down.
  • Another object of the present invention to provide an improved metal halide lamp employing a fused quartz arc tube as the light source which includes means for improved control of mercury condensation on the arc tube walls.
  • heat sink means physically engaging the arc tube of a metal halide lamp in a particular manner reduces the above defined light hole problem. More particularly, the light hole is reduced according to the present invention with external heat sink means physically engaging an arc tube wall intermediate the discharge electrodes adjacent the hot spot region of the arc tube.
  • Light loss caused by mercury recondensation on the present arc tube walls during restart should also be less.
  • a slower heating of the arc tube wall at the heat sink location relative to adjoining arc tube walls will impede mercury recondensation on the hotter wall locations.
  • thermal management of mercury condensation in the arc tube proceeds in a distinctive manner during lamp cool-down and restart.
  • the present heat sink means causes mercury to be condensed at a new location during lamp cool-down where it can be vaporized more readily during lamp restart while also causing the vaporized mercury to be less subject to recondensation elsewhere on the arc tube walls.
  • a suitable heat sink member for this purpose can be formed with a variety of heat-conductive solids to include metals such as copper and aluminum as well as ceramic compositions such as silicon carbide and aluminum nitride. Metal containing ceramic compositions such as alumina filled with heat-conductive metal particulates are also deemed useful construction materials for the present heat sink member.
  • a suitable heat sink member can have various physical configurations to include a heat-conductive metal element that is either maintained in physical contact with a wall of the arc tube member during lamp operation or bonded thereto with a refractory ceramic material.
  • a suitable heat sink construction for joinder to the arc tube wall can comprise a hollow fused quartz element containing a heat-conductive metal.
  • FIG. 1 is a side view depicting an arc tube for a metal halide lamp which incorporates heat sink means according to the present invention.
  • FIG. 2 is a graph illustrating the start-up mode of operation for the improved arc tube of FIG. 1 as compared with prior art arc tubes .
  • FIG. 3 is a side view depicting a different physical configuration for a modified arc tube according to the present invention.
  • FIG. 4 is a perspective view depicting an automotive headlamp incorporating the quartz arc tube of FIG. 3 oriented horizontally..
  • FIG. 1 depicts a typical fused quartz arc tube construction 10 employing heat sink means according to the present invention.
  • the arc tube 10 has a double-ended configuration with an elongated hollow body 12 shaped to provide neck sections 14 and 16 at each end of a bulbous shaped central portion 18.
  • Central portion 18 can have a typical overall length in the range from about five millimeters to about fifteen millimeters with a mid-point outer diameter from about three to about ten millimeters.
  • Wall portions 20 and 22 of the hollow quartz body 12 hermetically seal a pair of electrodes 24 and 26 at opposite ends of the bulbous mid-portion 18 which care separated from each other by a predetermined distance in the range of about two to about four millimeters.
  • Electrodes 24 and 26 both comprise rod-like members formed with a refractory metal such as tungsten or tungsten alloys and are configured to be of the same physical size when operated with an alternating current power source while generally being of dissimilar size when operated with a direct current power source.
  • the electrode members are also of the already known spot-mode type so as to develop a thermionic arc condition within the arc tube 10 in a substantially instantaneous manner.
  • Both electrodes 24 and 26 are hermetically sealed within the quartz envelope 12 with thin refractory metal foil elements 28 and 30 that are further connected to outer lead wire conductor 32 and 34, respectively.
  • a fill (not shown) of xenon, mercury and a metal halide is further contained within the sealed cavity 18 of the quartz envelope .
  • Refractory metal coils 36 and 38 serve only to centrally position the electrode members at the ends of the sealed arc tube envelope.
  • Arc tube 10 still further includes a heat sink member 40 secured to the outer surface of the arc tube top wall 20.
  • heat sink member 40 is positioned approximately midway between the spaced-apart electrodes 24 and 26 so as to coincide with the hot spot region of the arc tube during lamp operation.
  • the heat sink member may comprise a short length of quartz tubing 42 either heat sealed or adhesively bonded with a refractory ceramic material (not shown) directly to the arc tube wall and contains a fill of heat-conductive metal 44, such as aluminum, in the hollow cavity 46.
  • the heat being conductively removed through the walls of arc tube 10 by such heat sink means causes mercury to be selectively condensed within the arc tube when lamp operation is suspended. More particularly, the mercury condensation will now be primarily limited within the arc tube cavity 18 to only that region adjacent to heat sink member 40 rather than occurring throughout the inner walls of the arc tube cavity.
  • the graph in FIG. 2 illustrates performance characteristics for a 30 watt size instant light xenon-metal halide lamp and shows the effectiveness of the present improvement.
  • Curve 50 represents light output measurements for such a lamp employing the heat sink means of the present invention.
  • the lamp contained a a xenon fill pressure of approximately four atmospheres.
  • Curve 52 represents comparable measurements for such a lamp without the present heat sink means. As can be noted from a comparison of curves 50 and 52, both lamps achieved an almost immediate xenon light peak at the instant of lamp start-up.
  • Light output for the lamp without the present heat sink means (curve 52) displayed the light loss previously described.
  • the lamp does supply the fifty percent of the steady state illumination required by such a lamp within 0.75 second from lamp start-up at a starting current value of approximately 5.5 amperes during the test measurement period.
  • the light loss experienced during start-up with a lamp construction according to the present invention (curve 50) is reduced, such that the lamp meets the desired performance standard by a greater margin.
  • a constant steady state light output is achieved under lamp operating conditions wherein the lamp current is exponentially reduced to a predetermined steady state value with the lamp electrodes being maintained in a temperature range from about 2200°C up to about the melting point of the refractory metal selected for electrode construction in order to sustain the arc discharge.
  • FIG. 3 depicts an arc tube assembly 60 wherein the arc tube member 62 physically engages a metal foil heat sink member 64 so as to enable the desired heat transfer cooperation therebetween.
  • heat sink member 64 is constructed of a spring-like heat-conductive metal bent in a U shape with extending arms 66 and 68. Arm 66 enables the heat sink member to be physically attached to support means of a lamp unit (not shown) whereas arm 68 exerts a mechanical spring force downward when physically engaged with the upper wall exterior surface of arc tube member 62.
  • a further curved section 70 in arm 68 conforms to the curved exterior wall of the arc tube 62 to help increase the effective heat transfer area between the heat sink and arc tube. As can be further seen in FIG.
  • fused quartz arc tube 62 employs the same double-ended configuration hereinbefore described. Accordingly, said arc tube includes a pair of spot-mode type discharge electrodes 72 and 74 hermetically sealed within respective neck portions 76 and 78 of the hollow quartz envelope at opposite ends of a bulbous central cavity 80.
  • the discharge electrodes are connected at the outer ends to refractory metal foil elements 82 and 84 with the seal elements being then connected to respective outer lead conductors 86 and 88.
  • a fill (not shown) of xenon, mercury and a metal halide is contained within the bulbous central cavity 80.
  • heat sink member 64 Placement of heat sink member 64 between the spaced-apart discharge electrodes 72 and 74 of the arc tube 62 at the top wall surface where the hot spot occurs enables maximum heat removal to be achieved.
  • the mass of the heat sink member substantially exceeds the quartz mass in the arc tube member.
  • arc tube 62 wherein the heat sink member 64 was formed with a copper metal block.
  • the arc tube was operated with a direct current power source enabling spot mode ignition of the discharge electrodes at a starting current level of approximately 5.5 amperes.
  • Light output of the tested arc tube substantially increased from the moment of lamp start-up and thereafter was maintained at a relatively steady state value.
  • the arc tube was starter with the heat sink member in place and run for approximately one minute after which the power was turned off and the arc tube allowed to cool for approximately fifteen minutes.
  • the heat sink member was then removed from physical contact with the top wall surface of the arc tube in order to visually observe where mercury had condensed within the arc tube cavity.
  • Mercury was found to have condensed on the top wall inner surface of the arc tube in a region primarily limited to the former location of the heat sink. It follows from these results that light loss is significantly reduced during lamp start-up when mercury condensation can be effectively directed to a limited region of the arc tube walls with the present heat sink means.
  • FIG. 4 is a perspective view depicting an automotive headlamp incorporating the quartz arc tube assembly 60 of FIG. 3 wherein the arc tube 62 is oriented in a horizontal axial manner.
  • the automotive headlamp 90 includes a reflector 9?, a lens 94 secured to the front section of the reflector, connection means 96 secured at the rear section of the reflector for connection to a power source, and the metal halide light source 62.
  • Reflector member 92 has a truncated parabolic contour with flat top and bottom wall portions 98 and 100, respectively, intersecting the parabolic curved portion 102.
  • Connection means 96 of the reflector includes prongs 104 and 106 which are capable of being connected to a ballast (not shown) which drives the lamp and which in turn is driven by the power source of the automotive vehicle.
  • the reflector 92 has a predetermined focal point 108 as measured along the axis 110 of the automotive headlamp 90 which is located at about mid-point of the arc tube 62.
  • Arc tube 62 is predeterminently positioned within the reflector 92 so as to be approximately disposed near the focal point 108 of the reflector.
  • the arc tube 62 is oriented along axis 110 of the reflector.
  • the reflector cooperates with its light source 62 by reason of its parabolic shape and with lens 94 affixed thereto being of a transparent material which can include prism elements (not shown) also cooperating to provide a predetermined forward projecting light beam from the light source.
  • Arc tube 62 is connected to the rear of reflector 92 by a pair of relatively stiff self-supporting lead conductors 112 and 114 which are further connected at the opposite ends to the respective prong elements 104 and 106.
  • Reflector 92 also includes a conventional heat shield 116 which is affixed to top wall portion 98 of the reflector.
  • a heat sink member 64 is physically supported from heat shield 116 so as to exert a downward spring force action upon also suspended arc tube 62. Since it will be apparent to those skilled in the art, however, that other structural arrangements may be utilized to provide heat sink means within a reflector member, it is not intended that the structural means shown limit the scope of the invention.
EP19910310000 1990-11-01 1991-10-30 Heat sink for metal halide lamp Withdrawn EP0484117A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US60809190A 1990-11-01 1990-11-01
US608091 2000-06-30

Publications (2)

Publication Number Publication Date
EP0484117A2 true EP0484117A2 (de) 1992-05-06
EP0484117A3 EP0484117A3 (en) 1992-12-30

Family

ID=24434996

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19910310000 Withdrawn EP0484117A3 (en) 1990-11-01 1991-10-30 Heat sink for metal halide lamp

Country Status (2)

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EP (1) EP0484117A3 (de)
JP (1) JPH04282552A (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2704934A1 (fr) * 1993-05-04 1994-11-10 Valeo Vision Projecteur de véhicule automobile équipé d'un moyen formant radiateur et d'un élément d'occultation ou de traitement de lumière.
WO2002056334A1 (en) * 2001-01-10 2002-07-18 Koninklijke Philips Electronics N.V. High-pressure gas discharge lamp with cooling arrangement
EP1304722A1 (de) * 2000-05-25 2003-04-23 Hamamatsu Photonics K. K. Lichtquelle
WO2003060950A2 (de) * 2002-01-16 2003-07-24 Wedeco Ag Water Technology Amalgamdotierter quecksilberniederdruckstrahlereinheit
CN109404865A (zh) * 2018-11-16 2019-03-01 西安交通大学 模块化多功能石英灯挂载架
CN112014028A (zh) * 2020-08-27 2020-12-01 北京智创芯源科技有限公司 一种石英管组件及其真空检验方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4311319B2 (ja) * 2004-09-22 2009-08-12 ウシオ電機株式会社 ショートアーク型放電ランプ

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2961564A (en) * 1958-10-02 1960-11-22 Gen Electric Pulsating electric discharge
JPH1033846A (ja) * 1996-07-19 1998-02-10 Shiro Katagiri ハンド・シュレッダー

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2961564A (en) * 1958-10-02 1960-11-22 Gen Electric Pulsating electric discharge
JPH1033846A (ja) * 1996-07-19 1998-02-10 Shiro Katagiri ハンド・シュレッダー

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 13, no. 220 (E-762)23 May 1989 & JP-A-10 33 846 ( HITACHI LTD ) *

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2704934A1 (fr) * 1993-05-04 1994-11-10 Valeo Vision Projecteur de véhicule automobile équipé d'un moyen formant radiateur et d'un élément d'occultation ou de traitement de lumière.
EP1304722A1 (de) * 2000-05-25 2003-04-23 Hamamatsu Photonics K. K. Lichtquelle
EP1304722A4 (de) * 2000-05-25 2005-07-27 Hamamatsu Photonics Kk Lichtquelle
WO2002056334A1 (en) * 2001-01-10 2002-07-18 Koninklijke Philips Electronics N.V. High-pressure gas discharge lamp with cooling arrangement
WO2003060950A2 (de) * 2002-01-16 2003-07-24 Wedeco Ag Water Technology Amalgamdotierter quecksilberniederdruckstrahlereinheit
WO2003060950A3 (de) * 2002-01-16 2004-01-22 Wedeco Ag Amalgamdotierter quecksilberniederdruckstrahlereinheit
US7061173B2 (en) 2002-01-16 2006-06-13 Wedeco Ag Water Technology Amalgam-doped low mercury low-pressure UV irradiator
CN109404865A (zh) * 2018-11-16 2019-03-01 西安交通大学 模块化多功能石英灯挂载架
CN112014028A (zh) * 2020-08-27 2020-12-01 北京智创芯源科技有限公司 一种石英管组件及其真空检验方法

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Publication number Publication date
EP0484117A3 (en) 1992-12-30
JPH04282552A (ja) 1992-10-07

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