EP0269958B1 - High-pressure discharge lamp having a single pinch - Google Patents

High-pressure discharge lamp having a single pinch Download PDF

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Publication number
EP0269958B1
EP0269958B1 EP87117107A EP87117107A EP0269958B1 EP 0269958 B1 EP0269958 B1 EP 0269958B1 EP 87117107 A EP87117107 A EP 87117107A EP 87117107 A EP87117107 A EP 87117107A EP 0269958 B1 EP0269958 B1 EP 0269958B1
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EP
European Patent Office
Prior art keywords
pin
discharge lamp
pressure discharge
shaft
lamp according
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EP87117107A
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German (de)
French (fr)
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EP0269958A2 (en
EP0269958A3 (en
Inventor
Achim Gosslar
Jürgen Dr. Heider
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Osram GmbH
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Patent Treuhand Gesellschaft fuer Elektrische Gluehlampen mbH
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    • 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
    • H01J61/0732—Main electrodes for high-pressure discharge lamps characterised by the construction of the electrode

Definitions

  • the invention is based on a high-pressure discharge lamp squeezed on one side according to the preamble of claim 1.
  • a one-piece electrode for a high-pressure discharge lamp pinched on one side, which consists of a straight shaft and a filament part which is angled at 90 ° with respect to the shaft, the individual turns of the filament part not touching one another. This means that improves the ignition behavior of this lamp.
  • Another high-pressure discharge lamp is known from GB-PS 2 072 412.
  • an electrode shape with a shaft and angled electrode tip is described, the entire electrode being made from a piece of wire; by bending the tip of the electrode opposite the straight shaft, the bow stability is improved.
  • the object of the invention is to improve the life behavior and the ignition behavior of these squeezed high-pressure discharge lamps at the same time.
  • This task is characterized by the characteristics of claim 1 solved. Further advantageous configurations can be found in the subclaims.
  • a major advantage of the invention is that the corrosion of the electrodes is greatly restricted. The mechanism responsible for this has not yet been elucidated. The change in the temperature profile along the electrodes caused by the high thermal capacity of the pins presumably results in a positive change in the halogen cycle, as a result of which the tungsten mining no longer occurs predominantly at the relatively cold places on the electrode shaft near the pinch.
  • the heat dissipation along the electrode shaft is low, since the diameter of the shaft wire can be kept small. Overall, therefore, the time from electrical breakdown to arc acceptance is shortened, so that the ignitability of the lamp is improved.
  • the increased heat capacity in the area of the electrode tips also reduces the amplitude of the periodic temperature fluctuations at the electrodes linked to the frequency of the alternating voltage and thus reduces the re-ignition peak.
  • a particularly advantageous ratio between high heat capacity at the electrode tip (ie in the area of the pins) and low heat dissipation along the electrode shaft can be achieved with a pin with a circular cross-section if the diameter and length of the pin correspond to the dimensions described in the subclaims.
  • the invention additionally enables targeted influencing and optimization of important parameters in the case of metal halide discharge lamps that are pinched on one side. Because of the larger cross-sectional area of the pin compared to the shaft, the surface of the pin projecting laterally on the shaft increases the heat radiation into the electrode dead spaces behind it, so that a more uniform temperature distribution in the discharge vessel is achieved.
  • the tip and shaft of the electrode are made from a single piece of wire.
  • This wire is doped with a substance with a low electron work function (ThO2).
  • ThO2 low electron work function
  • the lowest possible thorium content is desirable in order not to falsify the color spectrum of the lamp.
  • the use of a separate pin as the electrode tip allows only the electrode tip to be doped. This prevents maloperation, in which the arc is formed between the two electrode shafts in the vicinity of the pinch seal.
  • the inevitable co-doping of the shaft made this malfunction easier. By doping the pin, but without doping the electrode shaft at the same time, the reliability of the lamp operation is therefore increased.
  • the invention can be used advantageously in discharge vessels in which, due to the geometric relationships, the lateral distance between the electrode tip and the inner wall of the discharge vessel differs greatly in different directions (height and width) (for example, ellipsoidal discharge vessels, which are used in particular for projection purposes be used).
  • the shape of the cross-sectional area of the pin is chosen so that a different heat radiation is achieved in the different spatial directions and thus the different distance to the inner wall is taken into account.
  • the easiest to manufacture is a pin designed as a wire or sintered body with an elongated round cross section.
  • the corrosion-inhibiting effect of the pin has proven particularly advantageous in the case of lamps with fillings, the additives of which have a very high chemical aggressiveness towards built-in parts; this applies in particular to tin halides, which are required to achieve warm light colors.
  • the discharge vessel 2 As a filling (operating pressure approx. 35 bar), the discharge vessel 2 (with a volume of 0.65 cm3) contains not only mercury (approx. 15 mg) and a noble gas, but also metal iodides and bromides of sodium, tin, thallium, indium and lithium ( a total of 2.3 mg metal halides and an additional 0.2 mg tin).
  • the lamp 1 has a luminous efficacy of 83 lm / W at a nominal current of 1.8 A.
  • FIG. 2 shows the side view
  • FIG. 3 shows the front view of an electrode 4, 5 according to the invention as it is installed in the high-pressure discharge lamp 1 according to FIG. 1.
  • It has a straight shaft 15 of 10.2 mm in length made of undoped tungsten wire with a wire diameter of 0.6 mm.
  • a cylindrical pin 16 is laterally attached to the discharge-side end of the shaft 15.
  • the pin 16 is fastened to the shaft 15 by butt welding, so that the pin 16 and shaft 15 are at right angles to one another.
  • the discharge runs transversely to the two shafts 15 arranged parallel to one another.
  • the pins 16 are arranged approximately at half the height of the discharge volume, so that a possible influence of the burning position on the operating behavior is minimized.
  • a tungsten wire enriched with 0.7% thorium dioxide is used as pin 16.
  • An emitter paste is not required.
  • the two pins 16 are arranged coaxially to one another and each have a length of 1.2 mm and a diameter of 1.2 mm, the electrode spacing being approximately 6-7 mm (type I version).
  • the diameter of the pins 16 is only 0.9 mm with the same length (1.2 mm); the shaft diameter is also somewhat smaller (0.5 mm).
  • a sintered body can also be used for the pin, which - pressed from doped tungsten powder - is welded to the end of the shaft.
  • Type I When using electrodes with pins with a high heat capacity, the electrode corrosion is significantly reduced.
  • the average lifespan of Type I was increased by about 20%, and Type II by about 10% compared to conventional lamps.
  • the basic structure largely corresponds to the lamp version shown in FIG. 1 with a higher power level.
  • the ellipsoid-like discharge volume has much smaller dimensions, with all three axes having different dimensions: longitudinal axis 5 mm; Transverse axis (width) 4 mm; vertical axis (height) 3.5 mm.
  • the filling of the discharge vessel (the has a volume of 0.07 cm3) is similar to the first embodiment, but the bromine is replaced by iodine and an additional excess of tin is introduced.
  • This lamp also has similarly improved operating properties as the lamp shown in the first exemplary embodiment.
  • FIG. 4 A front view of the electrode used for this lamp is shown in FIG. 4.
  • An adaptation to the ellipsoidal discharge vessel 2 ⁇ is achieved here by the elongated, round cross section of the pin.
  • the "long side" of the cross-sectional area of the pin has a greater heat radiation than the "transverse side”, which is why the pin on the electrode shaft is oriented so that the "long side” of the pin to the - further away and therefore colder - inner wall in Area of the transverse axis of the discharge vessel 2 ⁇ emits.
  • the straight shaft 17 is made of an undoped tungsten wire with a wire diameter of 0.3 mm; it has a length of 6.6 mm.
  • the pin 18 (made of 0.7 wt .-% ThO2 enriched tungsten) has a length of 0.7 mm; it has a width of 0.6 mm and a flattened height of 0.55 mm.
  • the dimensions shown in FIG. 4 are intended to illustrate the principle and are not to be understood to scale.
  • the flattened cross-sectional shape of the pin 18 can be achieved by using a wire either by subsequent rolling or already by the shape of the drawing die.
  • the molded parts used in the pressing already have a corresponding shape; in general there is also a greater inhomogeneity of the Heat radiation achievable.
  • a sintered body 19 is advantageously used in a cone-like shape (or in the form of a pyramid), the sintered body 19 having an ellipsoid-like base 20 (transverse axis d 1) which is welded to the side of the electrode shaft 21 (diameter d 2, where d 2 ⁇ d 1) ;
  • the arc discharge begins at the rounded tip 22 of the sintered body 19.
  • the area of the base 20 of the cone which projects transversely to the discharge on the shaft 21 then heats up the dead space.
  • fillings with other metals and halides can also be used, for example, a filling with iodides of sodium and thallium and several rare earths (Dy, Ho, Tm) achieves a higher color temperature.
  • iodides of sodium and thallium and several rare earths Dy, Ho, Tm
  • the exact dimensions of the pin depend on the geometry of the discharge vessel and the power consumption of the lamp. A compromise must be found between the containment of electrode corrosion and good ignitability.
  • the composition of the lamp fill is of great importance.
  • the electrode dimensions are matched to the filling system used.

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  • Discharge Lamp (AREA)
  • Vessels And Coating Films For Discharge Lamps (AREA)
  • Discharge Lamps And Accessories Thereof (AREA)

Description

Die Erfindung geht aus von einer einseitig gequetschten Hochdruckentladungslampe nach dem Oberbegriff des Anspruchs 1.The invention is based on a high-pressure discharge lamp squeezed on one side according to the preamble of claim 1.

Aus der GB-A-2126415 ist für eine einseitig gequetschte Hochdruckentladungslampe eine einteilige Elektrode bekannt, die aus einem geraden Schaft und einem Wendelteil besteht, das in Bezug auf den Schaft un 90° abgewinkelt ist, wobei sich die einzelnen Windungen des Wendelteils nicht berühren. Dadurch wird u.a. das Zündverhalten dieser Lampe verbessert.From GB-A-2126415 a one-piece electrode is known for a high-pressure discharge lamp pinched on one side, which consists of a straight shaft and a filament part which is angled at 90 ° with respect to the shaft, the individual turns of the filament part not touching one another. This means that improves the ignition behavior of this lamp.

Eine andere Hochdruckentladungslampe ist aus der GB-PS 2 072 412 bekannt. Dort, wird eine Elektrodenform mit Schaft und abgewinkelter Elektrodenspitze beschrieben, wobei die gesamte Elektrode aus einem Drahtstück gefertigt ist; durch die Abwinklung der Elektrodenspitze gengenüber dem geraden Schaft wird die Bogenstabilität verbessert.Another high-pressure discharge lamp is known from GB-PS 2 072 412. There, an electrode shape with a shaft and angled electrode tip is described, the entire electrode being made from a piece of wire; by bending the tip of the electrode opposite the straight shaft, the bow stability is improved.

Die Lebensdauer dieser Lampen ist dadurch eingeschränkt, daß die aggressive Füllung eine schnelle Korrosion der Elektroden bewirkt. Besonders stark tritt dieses Problem bei Füllungen auf, die einen hohen Anteil an Zinnhalogeniden enthalten. Zwar ließe sich die Korrosion durch Verwendung eines möglichst dicken Elektrodendrahtes hinauszögern, doch würde dabei das Zündverhalten der Lampe deutlich verschlechtert (Technisch-wissenschaftliche Abhandlungen der OSRAM-Gesellschaft, Bd. 12, S. 65 ff, Springer-Verlag Berlin, 1986).The service life of these lamps is limited by the fact that the aggressive filling causes the electrodes to corrode quickly. This problem occurs particularly strongly with fillings which contain a high proportion of tin halides. Corrosion could be delayed by using an electrode wire that was as thick as possible, but the ignition behavior of the lamp would be significantly impaired (technical-scientific treatises by OSRAM-Gesellschaft, Vol. 12, pp. 65 ff, Springer-Verlag Berlin, 1986).

Aufgabe der Erfindung ist es, gleichzeitig das Lebensdauerverhalten und das Zündverhalten dieser einseitig gequetschten Hochdruckentladungslampen zu verbessern. Diese Aufgabe wird durch die kennzeichnenden Merkmale des Anspruchs 1 gelöst. Weitere vorteilhafte Ausgestaltungen können den Unteransprüchen entnommen werden.The object of the invention is to improve the life behavior and the ignition behavior of these squeezed high-pressure discharge lamps at the same time. This task is characterized by the characteristics of claim 1 solved. Further advantageous configurations can be found in the subclaims.

Ein wesentlicher Vorteil der Erfindung besteht darin, daß die Korrosion der Elektroden stark eingeschränkt wird. Der dafür verantwortliche Mechanismus ist noch nicht aufgeklärt. Vermutlich bedingt die durch die hohe Wärmekapazität der Stifte hervorgerufene Änderung des Temperaturprofils entlang der Elektroden eine positive Veränderung im Halogenkreislauf, wodurch sich der Wolframabbau nicht mehr überwiegend an den relativ kalten Stellen am Elektrodenschaft in der Nähe der Einquetschung vollzieht.A major advantage of the invention is that the corrosion of the electrodes is greatly restricted. The mechanism responsible for this has not yet been elucidated. The change in the temperature profile along the electrodes caused by the high thermal capacity of the pins presumably results in a positive change in the halogen cycle, as a result of which the tungsten mining no longer occurs predominantly at the relatively cold places on the electrode shaft near the pinch.

Gleichzeitig ist die Wärmeableitung entlang des Elektrodenschafts gering, da der Durchmesser des Schaftdrahtes klein gehalten werden kann. Insgesamt wird daher die Zeit vom elektrischen Durchschlag bis zur Bogenübernahme verkürzt, so daß die Zündwilligkeit der Lampe verbessert wird. Die erhöhte Wärmekapazität im Bereich der Elektrodenspitzen vermindert zudem auch die Amplitude der mit der Frequenz der Wechselspannung verknüpften periodischen Temperaturschwankungen an den Elektroden und erniedrigt damit die Wiederzündspitze.At the same time, the heat dissipation along the electrode shaft is low, since the diameter of the shaft wire can be kept small. Overall, therefore, the time from electrical breakdown to arc acceptance is shortened, so that the ignitability of the lamp is improved. The increased heat capacity in the area of the electrode tips also reduces the amplitude of the periodic temperature fluctuations at the electrodes linked to the frequency of the alternating voltage and thus reduces the re-ignition peak.

Ein besonders vorteilhaftes Verhältnis zwischen hoher Wärmekapazität an der Elektrodenspitze (d.i. im Bereich der Stifte) und geringer Wärmeableitung entlang des Elektrodenschaftes läßt sich bei einem Stift mit kreisförmigem Querschnitt erzielen, wenn Durchmesser und Länge des Stiftes den in den Unteransprüchen beschriebenen Abmessungen entsprechen.A particularly advantageous ratio between high heat capacity at the electrode tip (ie in the area of the pins) and low heat dissipation along the electrode shaft can be achieved with a pin with a circular cross-section if the diameter and length of the pin correspond to the dimensions described in the subclaims.

Die Erfindung ermöglicht zusätzlich eine gezielte Beeinflussung und Optimierung wichtiger Parameter bei einseitig gequetschten Metallhalogenidentladungslampen. Die - infolge der größeren Querschnittsfläche des Stiftes im Vergleich zum Schaft - seitlich am Schaft überstehende Fläche des Stiftes erhöht die Wärmeabstrahlung in die dahinterliegenden Elektrodentoträume, so daß eine gleichmäßigere Temperaturverteilung im Entladungsgefäß erreicht wird.The invention additionally enables targeted influencing and optimization of important parameters in the case of metal halide discharge lamps that are pinched on one side. Because of the larger cross-sectional area of the pin compared to the shaft, the surface of the pin projecting laterally on the shaft increases the heat radiation into the electrode dead spaces behind it, so that a more uniform temperature distribution in the discharge vessel is achieved.

Bei konventionellen Lampen sind Spitze und Schaft der Elektrode aus einem Stück Draht gefertigt. Dieser Draht ist mit einer Substanz mit geringer Elektronenaustrittsarbeit (ThO₂) dotiert. Ein möglichst geringer Thoriumgehalt ist wünschenswert, um nicht das Farbspektrum der Lampe zu verfälschen. Die Verwendung eines separaten Stifts als Elektrodenspitze erlaubt es, nur die Elektrodenspitze zu dotieren. Dadurch wird ein Fehlbetrieb verhindert, bei dem der Bogen sich zwischen den beiden Elektrodenschäften in der Nähe der Quetschdichtung ausbildet. Bei konventionellen Lampen erleichterte die unvermeidliche Mit-Dotierung des Schaftes diese Fehlfunktion. Durch Dotierung des Stiftes, ohne jedoch gleichzeitig den Elektrodenschaft zu dotieren, wird daher die Zuverlässigkeit das Lampenbetriebs erhöht.With conventional lamps, the tip and shaft of the electrode are made from a single piece of wire. This wire is doped with a substance with a low electron work function (ThO₂). The lowest possible thorium content is desirable in order not to falsify the color spectrum of the lamp. The use of a separate pin as the electrode tip allows only the electrode tip to be doped. This prevents maloperation, in which the arc is formed between the two electrode shafts in the vicinity of the pinch seal. With conventional lamps, the inevitable co-doping of the shaft made this malfunction easier. By doping the pin, but without doping the electrode shaft at the same time, the reliability of the lamp operation is therefore increased.

Insbesondere läßt sich die Erfindung vorteilhaft bei Entladungsgefäßen einsetzen, bei denen aufgrund der geometrischen Verhältnisse der seitliche Abstand der Elektrodenspitze zur Innenwand des Entladungsgefäßes in verschiedene Richtungen (Höhe und Breite) stark unterschiedlich ist (z.B. ellipsoidähnliche Entladungsgefäße, die insbesondere für Projektionszwecke verwendet werden). Bei einer Anordung gemäß der Erfindung wird die Form der Querschnittsfläche des Stiftes so gewählt, daß eine unterschiedliche Wärmeabstrahlung in die verschiedenen Raumrichtungen erzielt wird und somit die unterschiedliche Entfernung zur Innenwand berücksichtigt wird. In dieser Hinsicht am einfachsten herzustellen ist ein als Draht oder Sinterkörper ausgeführter Stift mit länglichrundem Querschnitt.In particular, the invention can be used advantageously in discharge vessels in which, due to the geometric relationships, the lateral distance between the electrode tip and the inner wall of the discharge vessel differs greatly in different directions (height and width) (for example, ellipsoidal discharge vessels, which are used in particular for projection purposes be used). In an arrangement according to the invention, the shape of the cross-sectional area of the pin is chosen so that a different heat radiation is achieved in the different spatial directions and thus the different distance to the inner wall is taken into account. In this regard, the easiest to manufacture is a pin designed as a wire or sintered body with an elongated round cross section.

Besonders vorteilhaft erweist sich die korrosionshemmende Wirkung des Stifts bei Lampen mit Füllungen, deren Zusätze eine sehr hohe chemische Aggressivität gegenüber Einbauteilen aufweisen; dies gilt insbesondere für Zinnhalogenide, die zum Erzielen warmer Lichtfarben benötigt werden.The corrosion-inhibiting effect of the pin has proven particularly advantageous in the case of lamps with fillings, the additives of which have a very high chemical aggressiveness towards built-in parts; this applies in particular to tin halides, which are required to achieve warm light colors.

Mehrere Ausführungsbeispiele der Erfindung werden anhand der beigefügten Zeichnungen näher erläutert. Es zeigen

Figur 1
den Aufbau einer Hochdruckentladungslampe mit einseitig gequetschtem Entladungsgefäß
Figur 2
eine Elektrode für die Hochdruckentladungslampe gemäß Figur 1 in Seitenansicht
Figur 3
die Vorderansicht der in Figur 2 gezeigten Elektrode
Figur 4
die Vorderansicht einer anderen Ausführungsform der Elektrode
Figur 5
die Vorderansicht (a) und Seitenansicht (b) einer weiteren Ausführungsform der Elektrode
In Figur 1 ist der Aufbau einer Hochdruckentladungslampe 1 mit einer Leistungsaufnahme von 150 W gezeigt. Die Lampe 1 besteht aus einem einseitig gequetschten Entladungsgefäß 2 aus Quarzglas, das von einem ebenfalls einseitig gequetschten Außenkolben 3 aus Quarzglas umschlossen ist. Der Außendurchmesser der Lampe beträgt etwa 25 mm, die Gesamtlänge etwa 84 mm. Das Entladungsgefäß 2 besitzt ein ellipsoidähnliches Entladungsvolumen mit drei "Achsen". Die Länge der größten "Achse", die entlang der Verbindungslinie zwischen den Spitzen der Elektroden 4, 5 ausgerichtet ist, beträgt ca. 10 mm. Die beiden kleineren "Achsen", die die Höhe und Breite des Entladungsvolumens bestimmen, sind etwa gleich groß (jeweils ca. 8 mm). Die Elektroden 4, 5 (in schematischer Darstellung) sind mittels Folien 6, 7 gasdicht in das Entladungsgefäß 2 eingeschmolzen und über die Stromzuführungen 8, 9, die Dichtungsfolien 10, 11 des Außenkolbens 3 und über weitere kurze Stromzuführungen 12, 13 mit den elektrischen Anschlüssen des Keramiksockels (nicht gezeigt) verbunden. In die Quetschung des Entladungsgefäßes 2 ist zusätzlich - über ein Drahstück - ein auf einem Metallplättchen aufgebrachtes Gettermaterial 14 potentialfrei eingeschmolzen.Several embodiments of the invention are explained in more detail with reference to the accompanying drawings. Show it
Figure 1
the construction of a high-pressure discharge lamp with a discharge vessel squeezed on one side
Figure 2
an electrode for the high pressure discharge lamp according to Figure 1 in side view
Figure 3
the front view of the electrode shown in Figure 2
Figure 4
the front view of another embodiment of the electrode
Figure 5
the front view (a) and side view (b) of a further embodiment of the electrode
FIG. 1 shows the construction of a high-pressure discharge lamp 1 with a power consumption of 150 W. The lamp 1 consists of a discharge vessel 2 made of quartz glass, which is squeezed on one side and is enclosed by an outer bulb 3 made of quartz glass, which is also squeezed on one side. The outer diameter of the lamp is about 25 mm, the total length about 84 mm. The discharge vessel 2 has an ellipsoid-like discharge volume with three "axes". The length of the largest "axis", which is aligned along the connecting line between the tips of the electrodes 4, 5, is approximately 10 mm. The two smaller "axes" that determine the height and width of the discharge volume are approximately the same size (each about 8 mm). The electrodes 4, 5 (in a schematic representation) are melted gas-tight into the discharge vessel 2 by means of foils 6, 7 and via the current leads 8, 9, the sealing foils 10, 11 of the outer bulb 3 and via further short current leads 12, 13 with the electrical connections of the ceramic base (not shown) connected. In the pinch of the discharge vessel 2, a getter material 14 applied to a metal plate is additionally melted potential-free via a piece of wire.

Als Füllung (Betriebsdruck ca. 35 bar) enthält das Entladungsgefäß 2 (bei einem Volumen von 0,65 cm³) neben Quecksilber (ca. 15 mg) und einem Edelgas auch Metalljodide und -bromide von Natrium, Zinn, Thallium, Indium und Lithium (insgesamt 2, 3 mg Metallhalogenide und zusätzlich 0,2 mg Zinn). Die Lampe 1 weist bei einem Nennstrom von 1, 8 A eine Lichtausbeute von 83 lm/W auf.As a filling (operating pressure approx. 35 bar), the discharge vessel 2 (with a volume of 0.65 cm³) contains not only mercury (approx. 15 mg) and a noble gas, but also metal iodides and bromides of sodium, tin, thallium, indium and lithium ( a total of 2.3 mg metal halides and an additional 0.2 mg tin). The lamp 1 has a luminous efficacy of 83 lm / W at a nominal current of 1.8 A.

Figur 2 zeigt die Seitenansicht, Figur 3 die Vorderansicht einer erfindungsgemäßen Elektrode 4, 5, wie sie in der Hochdruckentladungslampe 1 gemäß Figur 1 eingebaut ist. Sie weist einen geraden Schaft 15 von 10,2 mm Länge aus undotiertem Wolframdraht mit einem Drahtdurchmesser von 0,6 mm auf. Ein zylindrischer Stift 16 ist am entladungsseitigen Ende des Schaftes 15 seitlich angesetzt. Die Befestigung des Stiftes 16 am Schaft 15 erfolgt durch Stumpfschweißen, so daß Stift 16 und Schaft 15 im rechten Winkel zueinander stehen. Die Entladung verläuft quer zu den beiden parallel zueinander angeordneten Schäften 15.FIG. 2 shows the side view, FIG. 3 shows the front view of an electrode 4, 5 according to the invention as it is installed in the high-pressure discharge lamp 1 according to FIG. 1. It has a straight shaft 15 of 10.2 mm in length made of undoped tungsten wire with a wire diameter of 0.6 mm. A cylindrical pin 16 is laterally attached to the discharge-side end of the shaft 15. The pin 16 is fastened to the shaft 15 by butt welding, so that the pin 16 and shaft 15 are at right angles to one another. The discharge runs transversely to the two shafts 15 arranged parallel to one another.

Die Stifte 16 sind etwa in halber Höhe des Entladungsvolumens angeordnet, so daß ein möglicher Einfluß der Brennlage auf das Betriebsverhalten minimiert wird.The pins 16 are arranged approximately at half the height of the discharge volume, so that a possible influence of the burning position on the operating behavior is minimized.

Als Stift 16 wird ein Wolframdraht, mit 0,7 % Thoriumdioxid angereichert, verwendet. Eine Emitterpaste wird nicht benötigt. Die beiden Stifte 16 sind koaxial zueinander angeordnet und haben jeweils eine Länge von 1,2 mm und einen Durchmesser von 1,2 mm, wobei der Elektrodenabstand ca. 6 - 7 mm beträgt (Typ I-Version). In einem anderen Ausführungsbeispiel (Typ II) beträgt der Durchmesser der Stifte 16 nur 0,9 mm bei gleicher Länge (1,2 mm); auch der Schaftdurchmesser ist etwas kleiner (0,5 mm).A tungsten wire enriched with 0.7% thorium dioxide is used as pin 16. An emitter paste is not required. The two pins 16 are arranged coaxially to one another and each have a length of 1.2 mm and a diameter of 1.2 mm, the electrode spacing being approximately 6-7 mm (type I version). In another embodiment (type II) the diameter of the pins 16 is only 0.9 mm with the same length (1.2 mm); the shaft diameter is also somewhat smaller (0.5 mm).

Statt Wolframdraht kann für den Stift auch ein Sinterkörper verwendet werden, der - aus dotiertem Wolframpulver gepreßt - an das Ende des Schaftes angeschweißt wird.Instead of tungsten wire, a sintered body can also be used for the pin, which - pressed from doped tungsten powder - is welded to the end of the shaft.

Ein Vergleich des Betriebsverhaltens von Lampen mit konventionellen Elektrodenspitzen (d.h. Durchmesser von Schaft und Elektrodenspitze sind gleich groß) und von Lampen mit Stiften hoher Wärmekapazität als Elektrodenspitzen liefert folgende Ergebnisse:A comparison of the operating behavior of lamps with conventional electrode tips (i.e. the diameter of the shaft and the electrode tip are the same size) and of lamps with pins with a high heat capacity as electrode tips provides the following results:

Bei Verwendung von Elektroden mit Stiften hoher Wärmekapazität ist die Elektrodenkorrosion deutlich herabgesetzt. Die mittlere Lebensdauer konnte beim Typ I um etwa 20 %, beim Typ II um etwa 10 % gegenüber konventionellen Lampen gesteigert werden.When using electrodes with pins with a high heat capacity, the electrode corrosion is significantly reduced. The average lifespan of Type I was increased by about 20%, and Type II by about 10% compared to conventional lamps.

Ein Maß zur Beurteilung der Zündwilligkeit gibt das Verhältnis (UW/UB) von Wiederzündspannung (UW) zu Brennspannung (UB) einer Lampe. Je kleiner dieses Verhältnis ist, umso besser ist die Bogenübernahme. Bei den Lampen, deren Elektrode einen Stift vom Typ I enthält, ist erwartungsgemäß die Zündwilligkeit besser (UW/UB = 1,60) als bei Lampen mit konventionellen abgewinkelten Elektroden (UW/UB = 1,80). Bei Lampen, deren Elektroden einen Stift vom Typ II enthalten, ist die Zündwilligkeit sogar noch etwas besser (UW/UB = 1,56); jedoch wird die Elektrodenkorrosion nicht so wirkungsvoll eingedämmt (s.o.).The ratio (U W / U B ) of the re-ignition voltage (U W ) to the operating voltage (U B ) of a lamp provides a measure of the willingness to ignite. The smaller this ratio, the better the sheet transfer. As is to be expected, the ignitability is better for lamps whose electrodes contain a type I pin (U W / U B = 1.60) than for lamps with conventional angled electrodes (U W / U B = 1.80). In the case of lamps whose electrodes contain a type II pin, the ignitability is even slightly better (U W / U B = 1.56); however, electrode corrosion is not so effectively contained (see above).

Bei einem Ausführungsbeispiel einer Hochdruckentladungslampe mit 35 W Leistungsaufnahme entspricht der prinzipielle Aufbau weitgehend der in Figur 1 gezeigten Lampenversion mit höherer Leistungsstufe. Das ellipsoidähnliche Entladungsvolumen besitzt jedoch wesentlich kleinere Abmessungen, wobei alle drei Achsen unterschiedliche Abmessungen aufweisen: Längsachse 5 mm; Querachse (Breite) 4 mm; vertikale Achse (Höhe) 3,5 mm. Die Füllung des Entladungsgefäßes (das ein Volumen 0,07 cm³ aufweist) ist ähnlich dem ersten Auführungsbeispiel, jedoch ist das Brom durch Jod ersetzt und ein zusätzlicher Überschuß an Zinn eingebracht. Auch diese Lampe weist ähnlich verbesserte Betriebseigenschaften auf wie die im ersten Ausführungsbeispiel gezeigte Lampe.In one embodiment of a high-pressure discharge lamp with a power consumption of 35 W, the basic structure largely corresponds to the lamp version shown in FIG. 1 with a higher power level. However, the ellipsoid-like discharge volume has much smaller dimensions, with all three axes having different dimensions: longitudinal axis 5 mm; Transverse axis (width) 4 mm; vertical axis (height) 3.5 mm. The filling of the discharge vessel (the has a volume of 0.07 cm³) is similar to the first embodiment, but the bromine is replaced by iodine and an additional excess of tin is introduced. This lamp also has similarly improved operating properties as the lamp shown in the first exemplary embodiment.

Eine Vorderansicht der für diese Lampe benutzten Elektrode zeigt Figur 4. Eine Anpassung an das ellipsoidähnliche Entladungsgefäß 2ʹ wird hierbei durch den länglichrunden Querschnitt des Stiftes erreicht. Zu beachten ist, daß hierbei die "Längsseite" der Querschnittsfläche des Stiftes ein stärkere Wärmeabstrahlung als die "Querseite" besitzt, weshalb der Stift am Elektrodenschaft so orientiert ist, daß die "Längsseite" des Stiftes zur - weiter entfernten und daher kälteren - Innenwand im Bereich der Querachse des Entladungsgefäßes 2ʹ abstrahlt. Im einzelnen ist der gerade Schaft 17 aus einem undotierten Wolframdraht mit einem Drahtdurchmesser von 0,3 mm hergestellt; er hat eine Länge von 6,6 mm. Der Stift 18 (aus mit 0,7 Gew.-% ThO₂ angereichertem Wolfram) hat eine Länge von 0,7 mm; er weist eine Breite von 0,6 mm und eine abgeplattete Höhe von 0,55 mm auf. Die in Figur 4 gezeigten Abmessungen sollen das Prinzip verdeutlichen und sind nicht maßstäblich aufzufassen.A front view of the electrode used for this lamp is shown in FIG. 4. An adaptation to the ellipsoidal discharge vessel 2ʹ is achieved here by the elongated, round cross section of the pin. It should be noted that the "long side" of the cross-sectional area of the pin has a greater heat radiation than the "transverse side", which is why the pin on the electrode shaft is oriented so that the "long side" of the pin to the - further away and therefore colder - inner wall in Area of the transverse axis of the discharge vessel 2ʹ emits. In particular, the straight shaft 17 is made of an undoped tungsten wire with a wire diameter of 0.3 mm; it has a length of 6.6 mm. The pin 18 (made of 0.7 wt .-% ThO₂ enriched tungsten) has a length of 0.7 mm; it has a width of 0.6 mm and a flattened height of 0.55 mm. The dimensions shown in FIG. 4 are intended to illustrate the principle and are not to be understood to scale.

Die abgeplattete Querschnittsform des Stiftes 18 kann bei Verwendung eines Drahtes entweder durch nachträgliches Walzen oder bereits durch die Form des Ziehsteins erzielt werden. Bei Verwendung von Sinterkörpern weisen bereits die beim Pressen verwendeten Formteile eine entsprechende Gestalt auf; im allgemeinen ist dabei auch eine stärkere Inhomogenität der Wärmeabstrahlung erzielbar.The flattened cross-sectional shape of the pin 18 can be achieved by using a wire either by subsequent rolling or already by the shape of the drawing die. When using sintered bodies, the molded parts used in the pressing already have a corresponding shape; in general there is also a greater inhomogeneity of the Heat radiation achievable.

Bei Elektrodenspitzen aus Sinterkörpern ist es gemäß Fig. 5a und b besonders gut möglich, nur die Wärmeabstrahlung in die hinter den Elektroden liegenden Toträume zu verbessern, falls das Entladungsgefäß dort die kälteste Stelle aufweist. Zu diesem Zweck wird vorteilhaft ein Sinterkörper 19 in konusähnlicher Gestalt (oder in Gestalt einer Pyramide) verwendet, wobei der Sinterkörper 19 eine ellipsoidähnliche Grundfläche 20 (Querachse d₁) besitzt, die am Elektrodenschaft 21 (Durchmesser d₂, wobei d₂ < d₁) seitlich angeschweißt ist; an der abgerundeten Spitze 22 des Sinterkörpers 19 setzt die Bogenentladung an. Der am Schaft 21 quer zur Entladung überstehende Bereich der Grundfläche 20 des Konus heizt dann den Totraum auf.In the case of electrode tips made of sintered bodies, it is particularly well possible according to FIGS. 5 a and b to improve only the heat radiation into the dead spaces behind the electrodes if the discharge vessel has the coldest point there. For this purpose, a sintered body 19 is advantageously used in a cone-like shape (or in the form of a pyramid), the sintered body 19 having an ellipsoid-like base 20 (transverse axis d 1) which is welded to the side of the electrode shaft 21 (diameter d 2, where d 2 <d 1) ; The arc discharge begins at the rounded tip 22 of the sintered body 19. The area of the base 20 of the cone which projects transversely to the discharge on the shaft 21 then heats up the dead space.

Zur Erzielung anderer Farbtemperaturen und Lichtfarben können auch Füllungen mit anderen Metallen und Halogeniden verwendet werden, beispielsweise wird durch eine Füllung mit Jodiden des Natrium und Thallium sowie mehrere Seltener Erden (Dy, Ho, Tm) eine höhere Farbtemperatur erzielt.To achieve different color temperatures and light colors, fillings with other metals and halides can also be used, for example, a filling with iodides of sodium and thallium and several rare earths (Dy, Ho, Tm) achieves a higher color temperature.

Die genauen Abmessungen des Stiftes hängen jeweils von der Geometrie des Entladungsgefäßes und der Leistungsaufnahme der Lampe ab. Es muß dabei ein Kompromiß zwischen der Eindämmung der Elektrodenkorrosion und guter Zündwilligkeit gefunden werden. Dabei ist auch die Zusammensetzung der Lampenfüllung von großer Bedeutung. Die Elektrodenabmessungen sind jeweils auf das verwendete Füllungssystem abgestimmt.The exact dimensions of the pin depend on the geometry of the discharge vessel and the power consumption of the lamp. A compromise must be found between the containment of electrode corrosion and good ignitability. The composition of the lamp fill is of great importance. The electrode dimensions are matched to the filling system used.

Claims (9)

  1. High-pressure low-power discharge lamp having a single pinch, having a discharge vessel (2) made of quartz glass which is surrounded if appropriate by an outer piston (3), and having a filling of mercury and noble gas with additives of metals and/or their halides and having two electrodes (4, 5) composed of a straight shaft (15) and an electrode tip bent at an angle , the two shafts (15) being arranged parallel to one another, characterised in that the tip of each electrode (4, 5) is constructed as a separate pin (16; 18) which is attached laterally to the end of the shaft (15; 17), the cross-sectional surface of the pin (16; 18) being larger than that of the shaft (15; 17).
  2. High-pressure discharge lamp according to Claim 1, characterised in that the pin (16) has a circular cross-section.
  3. High-pressure discharge lamp according to Claim 1, characterised in that the pin (18) has an oval cross-section.
  4. High-pressure discharge lamp according to Claim 2 or 3, characterised in that the pin is produced as a wire element.
  5. High-pressure discharge lamp according to Claim 2 or 3, characterised in that the pin is produced as a sintered element.
  6. High-pressure discharge lamp according to Claim 2, characterised in that the diameter of the pin (16) is greater than the diameter of the shaft (15) by a factor of 1.5 to 3.
  7. High-pressure discharge lamp according to Claim 6, characterised in that the ratio of the length to the diameter of the pin (16) is between 1 and 2.
  8. High-pressure discharge lamp according to Claim 1, characterised in that the pin is composed of doped tungsten, a dopant with a low electron emission work being used whilst the shaft is composed of non-doped tungsten.
  9. High-pressure discharge lamp according to Claim 1, characterised in that the filling additives contain tin as an essential component.
EP87117107A 1986-12-01 1987-11-19 High-pressure discharge lamp having a single pinch Expired - Lifetime EP0269958B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3640990 1986-12-01
DE19863640990 DE3640990A1 (en) 1986-12-01 1986-12-01 HIGH PRESSURE DISCHARGE LAMP, SEMI-SIDED

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EP0269958A2 EP0269958A2 (en) 1988-06-08
EP0269958A3 EP0269958A3 (en) 1989-10-11
EP0269958B1 true EP0269958B1 (en) 1993-02-10

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EP0381035B1 (en) * 1989-01-31 1994-08-03 Toshiba Lighting & Technology Corporation Single side-sealed metal vapor discharge lamp
JP2668434B2 (en) * 1989-01-31 1997-10-27 東芝ライテック株式会社 Metal halide lamp
NL9500350A (en) * 1994-02-25 1995-10-02 Ushio Electric Inc Metal halide lamp with a one-piece arrangement of a front cover and a reflector.
JP3211654B2 (en) * 1996-03-14 2001-09-25 松下電器産業株式会社 High pressure discharge lamp
JP3596453B2 (en) * 2000-09-28 2004-12-02 ウシオ電機株式会社 Short arc discharge lamp
DE10318051A1 (en) * 2003-04-17 2004-11-04 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH halogen bulb
DE102007061514A1 (en) * 2007-12-20 2009-06-25 Osram Gesellschaft mit beschränkter Haftung Electrode for a high-pressure discharge lamp and method for its production
KR101500092B1 (en) 2013-06-26 2015-03-06 현대자동차주식회사 Apparatus for preventing passive task-related fatigue of driver and method thereof

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Also Published As

Publication number Publication date
EP0269958A2 (en) 1988-06-08
JPH0584630B2 (en) 1993-12-02
DE3640990A1 (en) 1988-06-16
EP0269958A3 (en) 1989-10-11
US4937495A (en) 1990-06-26
JPS63148530A (en) 1988-06-21
DE3784144D1 (en) 1993-03-25

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