JP2008235126A - High-pressure discharge lamp and lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-pressure discharge lamp of which the translucent ceramic airtight container is miniaturized, reduced in weight, and then, reduced in breakage by improving the configuration of a pair of small diameter cylindrical parts in the translucent ceramic airtight container and in which the sealing amount of a discharge medium and the reduction rate during the lifetime are reduced. <P>SOLUTION: The high-pressure discharge lamp comprises: a translucent ceramic airtight container 1 equipped with a surrounding part 1a and the pair of the small-diameter cylindrical parts 1bA, 1Bb; a pair of current introducing conductors 2, 2; a pair of electrodes 3, 3 connected to the current introducing conductors; and a discharge medium. The lengths of the small-diameter cylindrical parts are different from each other. The sealing of the translucent ceramic airtight container between the short small-diameter cylindrical part 1Bb and the current introducing conductor inserted thereinto is formed by the fusion of a material of the same quality as that of at least one of the small-diameter cylindrical part and the current introducing conductor, and the sealing of the translucent ceramic airtight container between the long small-diameter cylindrical part 1bA and the current introducing conductor inserted thereinto is formed by the fusion of frit glass. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a high-pressure discharge lamp including a translucent ceramic hermetic container and an illumination device including the high-pressure discharge lamp.

  In a high-pressure discharge lamp equipped with a conventional translucent ceramic discharge vessel, various modes have been proposed or attempted in order to seal the discharge vessel via a current introduction conductor. Among them, the most widespread is an embodiment using a glass frit (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 06-196131

However, when a translucent ceramic discharge vessel is sealed using a glass frit as described in Patent Document 1, it cannot be said that the heat resistance of the glass frit is sufficiently high. In order to obtain it, the temperature of the sealing portion must be suppressed as required, and therefore the following configuration must be adopted.
(1) A so-called capillary structure is formed in which a pair of small-diameter cylindrical portions extend in the tube axis direction from both ends of the surrounding portion defining the discharge space.
(2) Reduce the tube wall load.

  The use of the above configuration causes the following problems.

As a result of the above (1), the total length of the lamp is increased. This leads to the following problem.
a) The strength of the capillary portion is lowered and easily broken.
b) The amount of the discharge medium such as a halide to be sealed is several times or more, and in some cases, 10 times or more as compared with the case where no capillary is formed. As a result, problems such as an increase in cost, stability of the discharge medium, a decrease in startability due to an increase in impure gas discharged from the discharge medium, white turbidity, blackening, and electrode wear are likely to occur.
c) In the case of vertical lighting, the heat generated by lighting concentrates on the upper part, the reaction with the discharge medium and free halogen becomes intense, and corrosion on the upper side occurs to shorten the life.

  Since the temperature is lowered by performing the above (2), the halide is not sufficiently evaporated and the vapor pressure cannot be increased. As a result, the luminous efficiency cannot be increased to the expected level. Further, it is not possible to use a halide having good light emission characteristics but high reactivity.

  The present invention improves the configuration of a pair of small-diameter cylindrical portions in a translucent ceramic hermetic container so that the translucent ceramic hermetic container is reduced in size, weight, and damage is reduced. An object of the present invention is to provide a high-pressure discharge lamp in which the rate of reduction is reduced.

    The high-pressure discharge lamp according to the present invention includes a light-transmitting ceramic hermetic container including a surrounding portion and a pair of long and short small-diameter cylindrical portions connected to both ends of the surrounding portion; and a pair of long and short small-diameter cylindrical portions of the light-transmitting ceramic air-tight container. A pair of current-introducing conductors inserted and sealed between the small-diameter cylindrical portions, respectively, and a pair of current-introducing conductors connected to the current-introducing conductor and sealed in the light-transmitting ceramics hermetic container And a discharge medium enclosed in a translucent ceramic hermetic container; and sealing the translucent ceramic hermetic container between a short small-diameter cylindrical portion and a current introduction conductor inserted therein Sealing of the translucent ceramic hermetic container between the long small-diameter cylindrical portion and the current-introducing conductor inserted therein is formed by fusing the same material with the material of at least one of the small-diameter cylindrical portion and the current introducing conductor. It is characterized that it is formed by fusion of the glass.

  The present invention includes the following aspects.

  [Translucent Ceramic Discharge Vessel] The translucent ceramic discharge vessel includes a single crystal metal oxide such as sapphire, a polycrystalline metal oxide such as translucent airtight aluminum oxide, yttrium-aluminum garnet (YAG ), Yttrium oxide (YOX), and polycrystalline non-oxide, for example, aluminum nitride (AlN), a light-transmitting and heat-resistant ceramic material, and the discharge space is hermetically sealed to the outside. A container to be formed. However, among the above materials, translucent polycrystalline alumina ceramics are suitable as a constituent material for translucent ceramic discharge vessels because they can be mass-produced industrially and are relatively easily available.

  In general, translucent polycrystalline alumina ceramics have an average crystal grain size of several tens of μm. In the present invention, the average crystal grain size of at least a short small diameter cylindrical part is 4 μm. The following are preferred. That is, when the average crystal grain size of at least the short small-diameter cylindrical portion is 4 μm or less, when the ceramic of the short small-diameter cylindrical portion is melted and sealed, the familiarity with the introduction conductor is good and the small diameter is obtained by melting. During cooling after the tube portion and the current introduction conductor are joined, cracks are unlikely to occur at the joined portion or in the vicinity thereof. In addition, when the average crystal grain size is 1 μm or less, cracking due to bonding is extremely reduced, which is more preferable. In the present invention, it is particularly excellent. Furthermore, when the average crystal grain size is 0.5 μm or less, cracks are hardly generated by joining, which is optimal.

  In the aspect in which the crystal average particle size of at least the short small-diameter cylindrical portion of the translucent ceramic hermetic container described above is 4 μm or less, the portion where the crystal average particle size is 4 μm or less may be only the short small-diameter cylindrical portion. Alternatively, the entire translucent ceramic hermetic container may be used. Further, if desired, the average crystal grain size may be 4 μm or less in a part other than the short small-diameter cylindrical portion.

  The translucency in the translucent ceramic hermetic container means that the light generated by the discharge can be transmitted to the outside and transmitted to the outside, not only transparent but also light diffusive. Also good. Further, at least the main part of the part surrounding the discharge space only needs to have translucency, and if necessary, when it has an incidental structure other than the main part, the part may be light-shielding. .

  The translucent ceramic hermetic container includes an encircling part to enclose the discharge space. The inside of the enclosure, that is, the discharge space is allowed to have an appropriate shape, for example, a spherical shape, an elliptical spherical shape, a substantially cylindrical shape, or the like. Various values can be selected as the volume of the discharge space according to the rated lamp power of the high-pressure discharge lamp, the distance between the electrodes, and the like. For example, in the case of a liquid crystal projector lamp, it can be 0.5 cc or less. In the case of a vehicle headlamp, it can be 0.05 cc or less. In the case of a general illumination lamp, it can be set to 1 cc or more and any of the following depending on the rated lamp power.

  Further, the translucent ceramic hermetic container includes a pair of long and short small-diameter cylindrical portions that communicate with the surrounding portion. The small diameter cylindrical portion functions to seal the translucent ceramic hermetic container by inserting at least a current introducing conductor, which will be described later, into the small diameter cylindrical portion and sealing the current introducing conductor to the small diameter cylindrical portion. Moreover, it can be made to function also in order to enclose the discharge medium mentioned later in the inside of a translucent ceramic airtight container, ie, an enclosure part.

  The short small-diameter cylindrical portion seals the light-transmitting ceramic hermetic container with a current introduction conductor inserted therein before enclosing a discharge medium described later. In order to facilitate sealing by a sealing means described later, the length of the short small-diameter cylindrical portion in the tube axis direction is preferably about 1 to 7 mm, preferably 1.5 to 4 mm.

  The long small-diameter cylindrical portion is sealed with a translucent ceramic hermetic container using a conventional frit glass after a discharge medium to be described later is sealed, and a so-called capillary structure is formed in the inside. The length of the long small diameter cylindrical portion in the tube axis direction is preferably set to 1.2 to 6 times the length of the short small diameter cylindrical portion in the tube axis direction. When the length of the long small diameter cylindrical portion is less than 1.2 times, it becomes difficult to form a capillary structure. Further, if the length of the long small-diameter cylindrical portion exceeds 6 times, the mechanical weakness described as the problem of the background art described above becomes remarkable because it is too long.

  As a means for previously sealing the current introduction conductor and the opening of the translucent ceramic discharge vessel, the present inventor uses the opening and the current introduction conductor inserted therein as the ceramic and the current introduction conductor in the opening. An invention was made in which sealing is performed by fusion of at least one of the materials of the same quality as the material of the portion facing the opening. One of the advantages of this sealing means is that the heat resistant temperature of the formed sealing portion is high, so that the length of the small diameter cylindrical portion of the translucent ceramic hermetic container can be minimized. Therefore, it is easy to reduce the size of the translucent ceramic hermetic container. On the other hand, this sealing means is somewhat difficult to seal after the discharge medium is sealed.

Therefore, the present inventor employs a suitable sealing means in which the ceramic is melted and welded to the current introduction conductor inserted in the short small diameter cylindrical portion. In the present invention, the means for melting the ceramic is not particularly limited. For example, if a ceramic having a short small-diameter cylindrical portion is heated and heated to a temperature equal to or higher than its melting temperature, the ceramic can be melted and adapted to the surface of the current introduction conductor inserted into the small-diameter cylindrical portion. Then, when the heating is stopped and the familiar part is cooled, the ceramic is solidified, and the current introduction conductor is sealed to the small-diameter cylindrical portion, and the translucent ceramic hermetic container is sealed. The means for heating the ceramic is not particularly limited. For example, a heat ray projection type local heating means such as a laser or a halogen bulb with a reflecting mirror, an induction heating means, and an electric heater can be used. As the laser, can be used, for example a YAG laser, CO ₂ laser and the like.

  When heating the entire circumference of the small-diameter cylindrical portion using the above-mentioned local heating means of the heat ray projection type, the local heating means is fixed to a predetermined distance from the small-diameter cylindrical portion, for example, the side of the small-diameter cylindrical portion, and the local heating By rotating either one or both of the opening of the translucent ceramic hermetic container and the local heating means while operating the means, the entire circumference of the small diameter cylindrical portion can be heated uniformly. However, if desired, the laser beam is irradiated from the extending direction of the elder brother cylinder parts, for example, the tube axis direction, a plurality of local heating means are arranged around the fixedly arranged small diameter cylinder parts, or the local heating means is The light-transmitting ceramic hermetic container can be heated in a stationary state by rotating around the small-diameter cylindrical portion or by disposing a heating means surrounding the entire circumference of the small-diameter cylindrical portion.

  Next, in order to manufacture a translucent ceramic hermetic container, the surrounding part may be formed by integrally molding, or may be formed by joining or fitting a plurality of components. Good. For example, in addition to the surrounding portion, a small diameter cylindrical portion can be integrally formed from the beginning at both ends of the surrounding portion. However, it is also possible to form an integral translucent ceramic hermetic container by, for example, preliminarily sintering the surrounding portion and the small-diameter cylindrical portion and then joining them as required, and sintering the whole. Alternatively, the cylindrical portion and the end plate portion can be pre-sintered separately and then joined together to sinter the whole, thereby forming an integrated surrounding portion.

  [About Current Introducing Conductor] The current introducing conductor is a conductor that functions to apply a voltage to an electrode to be described later, supply current to the electrode, and seal the translucent ceramic hermetic container. For this purpose, the tip side portion inserted into the inside of the small-diameter cylindrical portion of the translucent ceramic hermetic container is connected to the electrode, and the proximal end side is exposed to the outside of the translucent ceramic hermetic container. It should be noted that being exposed to the outside of the light-transmitting airtight container may or may not protrude outward from the light-transmitting ceramic airtight container. It only has to be there.

  In addition, the current introduction conductor is a sealing metal, that is, niobium (Nb), tantalum (which is a conductive metal whose thermal expansion coefficient is similar to that of the translucent ceramic constituting the translucent ceramic hermetic container. A metal such as Ta), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), platinum (Pt), molybdenum (Mo), and tungsten (W), cermet, or the like can be used. When aluminum oxide such as alumina ceramics is used as the material for the light-transmitting ceramic hermetic container, niobium and tantalum have an average thermal expansion coefficient almost the same as that of aluminum oxide, and molybdenum has an average thermal expansion coefficient. Since it is close to that of the oxide, it is suitable for sealing. In the case of yttrium oxide and YAG, the difference is small. When aluminum nitride is used for the translucent ceramic hermetic container, zirconium may be used for the current introduction conductor. Further, the current introduction conductor can be formed by joining a plurality of material portions. For example, a part is a metal part selected from the above group, and a cermet is joined to the metal part in the tube axis direction.

  The cermet may be made of one or more metals selected from the above group, such as molybdenum or tungsten, in which the ceramic material is alumina ceramic. Further, the cermet portion sealed in the translucent ceramic hermetic container of the current introduction conductor includes at least a metal component such as niobium (Nb), molybdenum (Mo) and tungsten, and a ceramic component such as alumina, YAG and yttria. Including, the content ratio of the metal component is allowed to be 5 to 60% by mass.

  Thus, when the cermet is configured as described above, when the portion to be sealed by the heating means is heated, it generally depends on the heating method, but in a translucent ceramic hermetic container, heat absorption is generally performed. Hard to occur. On the other hand, heat absorption increases on the cermet surface. As a result, the surface of the cermet is heated and the temperature rises, and further, the heat is transferred to the small-diameter cylindrical portion of the translucent ceramic hermetic container, so that the planned sealing portion melts. To do.

  Further, since the content of the metal component is 60% by mass or less, there is no large difference in the coefficient of thermal expansion of the translucent ceramic hermetic container, and the high pressure discharge lamp is compared with the case where the translucent ceramic hermetic container is in direct molybdenum contact. Damage and leakage due to heat shock when is turned on are less likely to occur.

  Furthermore, the current introduction conductor can be constituted by a rod-shaped body of a sealing metal such as niobium, a pipe-shaped body, a coil-shaped body, or the like. In the case of a rod-shaped body, it is allowed to wind a coil around the rod-shaped body. In the case of a pipe-like body or a coil-like body, the current introduction conductor must be capable of being closed so as not to hinder the inside of the translucent ceramic hermetic container from being sealed. Also, since niobium and the like are highly oxidative, when the high-pressure discharge lamp is lit in the atmosphere, an oxidation-resistant conductor is further connected to the current introduction conductor and the small diameter of the translucent ceramic hermetic container It is necessary to prevent the current introduction conductor from coming into contact with the atmosphere, for example, by covering a portion exposed from the tube portion to the outside with an airtight substance such as frit glass.

  Furthermore, the function of the current introduction conductor is mainly divided into a portion that is sealed to the small-diameter cylindrical portion of the translucent ceramic hermetic container and a portion that mainly supports the electrode. Therefore, in order to optimize each part for each function, each part is made of a different material or formed in a different size and structure, and connected to each other to form a current introduction conductor. Can be configured. For example, it is known that a portion sealed mainly to a small-diameter cylindrical portion of a translucent ceramic hermetic container is made of niobium and a portion mainly supporting an electrode is made of a halogen-resistant metal. Also in the present invention, it is allowed to configure the current introduction conductor by changing the specifications such as the material, size and shape according to the main function and connecting them in the tube axis direction. However, in the present invention, a conductive member made of the same material can be used over almost the entire length of the current introduction conductor if desired. In this case, other materials can be added around the conductive member as necessary in order to perform the respective functions. For example, the portion to be welded to the opening portion of the current introduction conductor does not necessarily need to be conductive. Therefore, a material having a high ceramic component composition ratio is provided around the conductive member, and a part of this member is welded. It may be.

Next, the sealing means between the short small diameter cylindrical portion of the translucent ceramic hermetic container and the current introduction conductor will be described. The present invention includes the following aspects. In any of the embodiments, the sealing is formed by fusing a material having the same quality as the material of the short small-diameter cylindrical portion of the translucent ceramic hermetic container and / or the sealing portion of the current introduction conductor.
(1) A mode in which the ceramic in the opening of the translucent ceramic discharge vessel is mainly fused to the current introduction conductor.
(2) A mode in which a portion of the current introduction conductor facing the opening of the translucent ceramic discharge vessel is mainly fused.
(3) A mode in which the ceramic in the opening of the translucent ceramic discharge vessel and the current introduction conductor are fused together.
(4) A mode in which the ceramic in the opening of the translucent ceramic discharge vessel and the sealing material of the same quality as the material of the portion of the current introduction conductor facing the opening of the translucent ceramic discharge vessel are mainly fused. Note that the sealing material may be either integrated with the current introduction conductor in advance or prepared separately from the current introduction conductor.

On the other hand, the sealing of the translucent ceramic hermetic container by the long small-diameter cylindrical portion of the translucent ceramic hermetic container and the current introduction conductor inserted therein is performed after the discharge medium described later is enclosed inside the enclosure part, A conventional ceramic sealing compound made of frit glass such as Al ₂ O ₃ , SiO ₂ and Dy ₂ O ₃ is interposed between the translucent ceramic hermetic container and the current introduction conductor.

  [Regarding Electrode] The electrode is a means for causing discharge of a discharge medium, which will be described later, inside the translucent ceramic hermetic container. In general, a pair of electrodes are disposed so as to be opposed to each other so that arc discharge is generated between the electrodes inside the translucent ceramic hermetic container. In the present invention, at least one electrode is connected to the introduction conductor and sealed in the translucent ceramic hermetic container.

  The electrode is connected to the current introduction conductor and supported at a predetermined position in the translucent ceramic hermetic container. For example, the proximal end of the electrode is connected to the distal end portion located on the inner side of the translucent ceramic hermetic container of the current introduction conductor.

  Furthermore, an electrode can be comprised by an electrode main part or / and an electrode axial part. The electrode main part is a part that serves as a starting point of discharge, and therefore functions mainly as a cathode and / or an anode, and can be directly connected to the current introduction conductor without going through the electrode shaft part as desired. Further, in order to increase the surface area of the electrode main part to improve heat dissipation, a tungsten coil can be wound as necessary, or the diameter can be made larger than that of the electrode shaft part. When the electrode includes an electrode shaft portion, the electrode shaft portion is integrally or welded with the electrode main portion, protrudes rearward from the back surface of the electrode main portion, supports the electrode main portion, and the current introduction conductor. Connect to. If desired, the electrode shaft portion and the tip portion of the current introduction conductor can be integrated with a single tungsten.

  Furthermore, tungsten, doped tungsten, triated tungsten, rhenium, tungsten-rhenium alloy, or the like can be used as an electrode material.

  Furthermore, when a pair of electrodes is used, they have a symmetrical structure in the case of an AC lighting type, but can be made an asymmetric structure in the case of a DC lighting type.

  [Discharge Medium] The discharge medium is a means for obtaining desired light emission by the discharge, but the configuration is not particularly limited in the present invention. For example, the following modes are allowed. However, it is preferably composed of a luminescent metal halide, a lamp voltage forming medium and a rare gas. In the present invention, “high-pressure discharge” refers to a discharge in which the pressure during lighting of the ionized medium is equal to or higher than atmospheric pressure, and is a concept including so-called ultrahigh-pressure discharge.

  The luminescent metal halide is a luminescent metal halide that mainly emits visible light, and various known metal halides can be employed. That is, the metal halide of the luminescent metal obtains visible light radiation having desired luminescent characteristics with respect to luminescent color, average color rendering index Ra, luminescent efficiency, etc., and further, the size and input of the translucent ceramic discharge vessel Depending on the power, any desired metal halide can be selected as desired. For example, sodium (Na), scandium (Sc), rare earth metals (such as dysprosium (Dy), thulium (Tm), holmium (Ho), praseodymium (Pr), lanthanum (La) and cerium (Ce)), thallium (Tl) ), Indium (In) and lithium (Li), one or a plurality of halides selected from the group consisting of.

  The lamp voltage forming medium is an effective medium for forming a lamp voltage. For example, mercury or a metal halide described below can be used. That is, a halide as a lamp voltage forming medium is a metal such as aluminum, which has a relatively high vapor pressure during lighting and a small amount of light in the visible region compared to the amount of light emitted in the visible region. Halides such as (Al), iron (Fe), zinc (Zn), antimony (Sb), and manganese (Mn) are suitable.

  The rare gas acts as a starting gas and a buffer gas, and xenon (Xe), argon (Ar), krypton (Kr), neon (Ne), or the like can be used alone or in combination.

  1. Luminescent metal halide + mercury + noble gas: a so-called mercury-containing metal halide lamp.

  2. Luminescent metal halide + halide as lamp voltage forming medium + rare gas: This is a so-called mercury-free metal halide lamp configuration that does not use mercury with a large environmental load.

  3. Mercury + noble gas: This is a so-called high-pressure mercury lamp configuration.

  4). Noble gas: When Xe is used as a noble gas, it is a so-called xenon lamp configuration.

  Next, in the halide of the luminescent metal, any one or plural kinds of iodine, bromine, chlorine or fluorine can be used as the halogen.

  [Regarding the Action of the Present Invention] In the present invention, before the discharge medium is sealed inside the translucent ceramic hermetic vessel, the material of the portion facing the opening of the ceramic of the short small-diameter cylindrical portion and / or the current introduction conductor In order to fuse the same quality material, the member to be melted is heated intensively using a heating means such as a laser. At this time, at least the other member to be fused is heated to such an extent that the surface thereof gets wet, so that the short small diameter cylindrical portion of the current introduction conductor and the translucent ceramic discharge vessel can be well sealed without using frit glass. Thus, the translucent ceramic hermetic container is sealed.

  The long small-diameter cylindrical portion of the translucent ceramic hermetic container is finally sealed with a current-introducing conductor using frit glass after introducing the discharge medium into the enclosure via the small-diameter cylindrical portion. Thus, the translucent ceramic hermetic container is sealed to form a high-pressure discharge lamp.

  [Other Configurations of the Present Invention] Although not an essential component of the present invention, the function of a high-pressure discharge lamp can be added or the performance can be improved by including some or all of the following configurations as desired. To do.

  (1) (Outer tube) The high-pressure discharge lamp of the present invention can be configured to light up in a state where the translucent ceramic hermetic container is exposed to the atmosphere. However, if necessary, the translucent ceramic hermetic container can be accommodated in the outer tube. Note that the inside of the outer tube may be vacuum, gas-filled, or an atmosphere communicating with the atmosphere.

  (2) (Reflecting mirror) The high-pressure discharge lamp of the present invention can be integrated with a reflecting mirror.

    The illuminating device of the present invention is characterized by comprising: an illuminating device main body; a high-pressure discharge lamp of the present invention disposed in the illuminating device main body; and a lighting circuit for lighting the high-pressure discharge lamp.

  In the present invention, the illumination device is a concept including all devices using a high-pressure discharge lamp as a light source. Examples include various outdoor and indoor lighting fixtures, automobile headlamps, image or video projection devices, marker lamps, signal lights, indicator lights, chemical reaction devices, inspection devices, and the like.

  The illuminating device main body refers to the remaining part of the illuminating device excluding the high-pressure discharge lamp and the lighting circuit.

  The lighting circuit may be disposed at a position separated from the lighting device main body.

  According to the present invention, a pair of long and short small diameter cylindrical portions are formed in a translucent ceramic hermetic container, the short small diameter cylindrical portion is directly sealed with the current introduction conductor, and the long small diameter cylindrical portion and the current introduction conductor are formed. Since the light-transmitting ceramic hermetic container is sealed by sealing with frit glass, the light-transmitting ceramic hermetic container is reduced in size and weight, and its damage is reduced. It is possible to provide a high-pressure discharge lamp with a reduction rate during the life.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

    1 and 2 show a metal halide lamp for an automobile headlamp as a first embodiment for implementing a high-pressure discharge lamp according to the present invention, FIG. 1 is a front view of the entire lamp, and FIG. 2 is an enlarged view of an arc tube. It is sectional drawing. The metal halide lamp MHL for automobile headlamps is mainly composed of a light emitting tube IT, an outer tube OT, lead wires L1 and L2, an insulating tube T, and a base B.

  The arc tube IT includes a translucent ceramic hermetic container 1, current introduction conductors 2, 2, electrodes 3, a seal portion 4, and a discharge medium.

  As shown in FIG. 2, the translucent ceramic hermetic container 1 is formed by integral molding with translucent ceramic as a main material, and includes an enclosing portion 1a and a pair of long and short small diameter cylindrical portions 1bA, 1bB. . The surrounding portion 1a is formed into a hollow bulging shape having a substantially constant thickness, and a discharge space 1c having the same shape is formed therein. The internal volume of the discharge space 1c is about 0.025 cc. The pair of long and short small-diameter cylindrical portions 1bA and 1bB are formed by thin cylindrical portions having different lengths that are integrally extended from both ends of the surrounding portion 1a in the tube axis direction. When the length in the tube axis direction of the long small diameter cylindrical portion 1bA is LA and the length in the tube axis direction of the short small diameter cylindrical portion is LB, the ratio LA / LB is expressed by the formula: 1.2 ≦ LA / LB ≦ 6 Is set to satisfy.

  The pair of current introduction conductors 2 and 2 are made of a sealing metal rod, and are inserted into the small-diameter cylindrical portions 1bA and 1bB of the translucent ceramic discharge vessel 1, respectively. One current introduction conductor 2 is sealed inside the short small-diameter cylindrical portion 1bB by welding the ceramic to the short small-diameter cylindrical portion 1bB, and the translucent ceramic hermetic container 1 is sealed in the short small-diameter cylindrical portion 1bB. ing. In FIG. 2, symbol s denotes a welded portion formed by melting ceramics. Therefore, the distal end portion of the current introduction conductor 2 is located in the short small-diameter cylindrical portion 1bB, and the proximal end portion is exposed to the outside of the translucent ceramic discharge vessel 1.

  The other current introduction conductor 2 is sealed to a long small diameter cylindrical portion 1bA by a seal portion 4 made of frit glass, and the translucent ceramic hermetic container 1 is sealed by the long small diameter cylindrical portion 1bA. Accordingly, the distal end portion of the current introduction conductor 2 is located in the long small-diameter cylindrical portion 1bB, and the proximal end portion is exposed to the outside of the translucent ceramic discharge vessel 1.

  The electrode 3 is made of a tungsten rod, and the diameter of the shaft portion is the same over the distal end portion, the intermediate portion, and the proximal end portion in the axial direction, and a part of the distal end portion and the intermediate portion is exposed in the discharge space 1c. The electrode 3 is supported along the tube axis direction of the translucent ceramic hermetic container 1 by connecting the base end of the electrode 3 to the tip of the current introduction conductor 2 by welding. A slight gap g, that is, a capillary is formed in the tube axis direction between the electrode 3 facing the intermediate portion of the electrode 3 and the inner surface of the cylindrical portion of the long small diameter cylindrical portion 1bA.

  The discharge medium includes a light emitting metal halide, a lamp voltage forming medium, and a rare gas. The medium for forming the lamp voltage is made of mercury or a halide for forming a lamp voltmeter. The lamp voltmeter-shaped halide is a metal halide having a high vapor pressure and a small amount of luminescence in the visible region in the presence of the luminescent metal halide compared to the luminescent metal.

  The outer tube OT has an ultraviolet cut performance and houses the arc tube IT inside. Further, the reduced diameter portions 5 (only one end on the right side is shown in the figure) at both ends of the outer tube OT are welded to a lead wire L2 described later. However, the inside of the outer tube OT is not airtight but communicates with the outside air.

  The lead wires L1 and L2 are connected to the base ends of the current introduction conductors 2 and 2 by welding to support the arc tube IT. The lead wire L1 extends along the tube axis, is led out into a base B which will be described later, and is connected to the other base terminal having a pin shape disposed in the center (not shown). The lead wire L2 has an intermediate portion folded back along the outer tube OT, introduced into the base B, and connected to one base terminal t1 having a ring shape disposed on the outer peripheral surface of the base B.

  The insulating tube T is made of a ceramic tube and covers the lead wire L2.

  The base B is standardized for automotive headlamps. It supports the arc tube IT and the outer tube OT planted along the central axis, and is attached to and detached from the back of the vehicle headlamp. Installed as possible. In addition, one cap terminal t1 having a ring shape disposed on the outer peripheral surface of the cylindrical portion so that it can be connected to the lamp socket on the power source side when mounted, and a concave portion with one end open formed inside the cylindrical portion In the inside, it is configured to include the other base terminal having a pin shape disposed so as to protrude in the axial direction at the center.

The high pressure discharge lamp is the arc tube shown in FIG.
Translucent ceramic hermetic container: Made of integral translucent alumina ceramic,
Enclosure: Maximum inner diameter 5mm, wall thickness 0.5mm, length 6mm, inner spherical surface
Short small diameter cylinder: 0.7mm inner diameter, 0.5mm wall thickness, 2mm length
Long small diameter cylinder: 0.7mm ID, 0.5mm wall thickness, 12mm length
Current introduction conductor: Nb-cermet (Mo: Al ₂ O ₃ = 50: 50% by volume) Joint electrode: Tungsten rod, distance between electrodes 4.2 mm
Discharge medium: luminescent metal halide DyI ₃ —NdI ₃ —CsI = 2.0 mg,
Lamp voltage forming halide ZnI ₂ = 0.7 mg,
Noble gas Xe1 atmospheric pressure sealing method: Non-sealed side = short small-diameter cylindrical part irradiated with YAG laser,
A current-introducing conductor with a ceramic welded electrode
A non-sealing side was formed by fusing to the cermet part.

Next, the discharge medium is sealed from the long small-diameter cylindrical part side, and the electrode is placed at the tip.
Insert the current-introducing conductor welded into the long small diameter cylinder and
The translucent ceramic hermetic container was sealed with glass.

[Comparative example]
A pair of small-diameter cylindrical parts; both 0.7mm inside diameter, 0.5mm wall thickness, 12mm long
Sealing method: The translucent ceramic hermetic container was sealed with frit glass on both the non-sealing side and the sealing side.
Discharge medium: luminescent metal halide DyI ₃ —NdI ₃ —CsI = 3.0 mg,
Lamp voltage forming halide ZnI ₂ = 1.0 mg,
Noble gas Xe1 atm. The other specifications are the same as those in Example 1.

FIG. 3 is a cross-sectional view of an arc tube showing a second embodiment for implementing the high-pressure discharge lamp of the present invention. In the figure, the same parts as those in FIG.

  In this embodiment, the translucent ceramic hermetic container 1 of the high-pressure discharge lamp has a short small-diameter cylindrical portion 1bB that is longer than that in the first embodiment.

  The high pressure discharge lamp is an arc tube shown in FIG.

Short small diameter cylinder: 0.7mm inner diameter, 0.5mm wall thickness, 10mm length
Discharge medium: luminescent metal halide DyI ₃ —NdI ₃ —CsI = 2.8 mg
Lamp voltage forming halide ZnI ₂ = 0.9 mg,
Noble gas Xe1 atm. The other specifications are the same as those in Example 1.

About the Example and the comparative example, the lighting test of 5000 hours was done by each 5 high pressure discharge lamps by vertical lighting. As a result, Examples 1 and 2 were not damaged by lighting up to 5000 hours. On the other hand, in the comparative example, three were damaged by the lighting 5000 hours.

  FIG. 4 is a table showing the amount of halide of the luminescent metal halide, the decrease rate on the left side, and the mass decrease rate of the light-transmitting ceramic hermetic container in the examples of the present invention in comparison with those in the comparative example.

  As can be understood from the table of FIG. 4, according to the present invention, the amount of discharge medium enclosed can be reduced, and the mass of the translucent ceramic hermetic container can be reduced. Although not shown in the figure, since the length of the translucent ceramic hermetic container in the tube axis direction is reduced, the high-pressure discharge lamp can be reduced in size and weight.

  FIG. 6 is a conceptual side view showing an automobile headlamp as an embodiment for implementing the illumination device of the present invention. In the figure, 11 is a headlamp body, 12 is a high pressure discharge lamp lighting device, and 13 is a metal halide lamp for automobile headlamps.

  The headlamp body 11 has a container shape, and includes a reflecting mirror 11a inside, a lens 11b on the front surface, and a lamp socket not shown.

  The high-pressure discharge lamp lighting device 12 has a circuit configuration shown in FIG. 3 and includes a main lighting circuit 12A and a starter 12B. The main lighting circuit 12A includes the boost chopper BUT and the full bridge inverter FBI of FIG. 3 as main components. Similarly, the starter 12B includes an igniter IG as a main component.

  The metal halide lamp 13 for automobile headlamps is mounted on the lamp socket and lights up.

The front view which shows the metal halide lamp for motor vehicle headlamps as a 1st form for implementing the high pressure discharge lamp of this invention Similarly enlarged sectional view of arc tube Sectional drawing of the arc tube which shows the 2nd form for implementing the high-pressure discharge lamp of this invention The table | surface which shows the enclosure amount of the halide of the luminescent metal in the Example of this invention, the same left reduction rate, and the mass reduction rate of a translucent ceramic hermetic container as compared with that of a comparative example. The conceptual side view which shows the motor vehicle headlamp as one form for implementing the illuminating device of this invention

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Translucent ceramic discharge vessel, 1a ... Enveloping part, 1bA ... Long small diameter cylindrical part, 1bB ... Short small diameter cylindrical part, 2 ... Current introduction conductor, 3 ... Electrode, 4 ... Seal part, g ... Slight gap, IT ... arc tube, s ... weld

Claims (4)

A translucent ceramic hermetic container comprising a surrounding portion and a pair of small-diameter cylindrical portions connected to both ends of the surrounding portion;
A pair of current introduction conductors inserted into the pair of small diameter cylindrical portions of the translucent ceramic hermetic container and sealing the translucent ceramic hermetic container between the pair of small diameter cylindrical portions;
A pair of electrodes connected to a current introduction conductor and sealed in a translucent ceramic hermetic container;
A discharge medium enclosed in a translucent ceramic hermetic container;
Comprising
The pair of small-diameter cylindrical portions have different lengths, and the translucent ceramic hermetic container is sealed between the short small-diameter cylindrical portion and the current introduction conductor inserted therein. It is formed by fusing at least one of the same materials as the conductor, and the sealing of the translucent ceramic hermetic container between the long small diameter cylindrical portion and the current introduction conductor inserted therein is formed by frit glass fusing. A high pressure discharge lamp characterized by the above.   2. The high-pressure discharge according to claim 1, wherein the pair of small diameter cylindrical portions of the translucent ceramic hermetic container has a length of the long small diameter cylindrical portion that is 1.2 to 6 times the length of the short small diameter cylindrical portion. lamp.   The sealing of the translucent ceramic hermetic container between the short small-diameter cylindrical portion and the current introduction conductor inserted therein is mainly formed by fusion of ceramics constituting the short small-diameter cylindrical portion. Item 3. The high-pressure discharge lamp according to Item 1 or 2. A lighting device body;
A high-pressure discharge lamp according to any one of claims 1 to 3 disposed in a lighting device body;
A lighting circuit for lighting the high-pressure discharge lamp;
An illumination device comprising:

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