JP2008108713A - High-pressure discharge lamp, high-pressure discharge lamp lighting device, and lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-pressure discharge lamp wherein cracks produced in ceramic of a sealed part are suppressed by regulating the dimensional relation of a small diameter tube part in an intended seal part, a current introducing conductor, and the sealed part formed by them within a prescribed range, a high-pressure discharge lamp lighting device, and a lighting system. <P>SOLUTION: This high-pressure discharge lamp is equipped with a translucent ceramic discharge vessel 1 having an enclosing part 1a and the small diameter tube part 1b, the current introducing conductor 3 inserted into the inside of the small diameter tube part, and sealed to the small diameter tube part mainly by fusion of the ceramic in the small diameter tube part in the translucent ceramic discharge vessel, an electrode 2 sealed and mounted in the translucent ceramic discharge vessel by connecting it to the current introducing conductor, and a discharge medium. When the cross section of the ceramic of the small diameter tube part is set as S<SB>T</SB>, and the cross section of the current introducing conductor is set as S<SB>W</SB>, in the immediate vicinity of the sealed part formed by sealing it to the current introducing conductor by fusion of the ceramic of the small diameter part, The ratio S<SB>W</SB>/S<SB>T</SB>satisfies the formula: 0.037≤S<SB>W</SB>/S<SB>T</SB>≤0.363. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a high-pressure discharge lamp including a translucent ceramics discharge vessel, a high-pressure discharge lamp lighting device using the same, and an illumination device.

  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 the small-diameter cylindrical portion extends in the tube axis direction from both ends of the surrounding portion that defines 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.
・ The capillary part is easily broken.
-The amount of discharge medium such as halide to be sealed needs to be several times or more, in some cases 10 times or more, compared to 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.

  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.

  As a result of research on sealing a light-transmitting ceramic discharge vessel without using frit glass, the present inventors have found a frit glass-less configuration. This frit glass-less configuration includes several embodiments using various materials and structures.

  However, the structure that can be sealed with relatively high reliability and stability is a sealing structure in which the ceramic in the portion to be sealed of the translucent ceramic discharge vessel is heated and melted and welded to the current introduction conductor. I understood that.

  Therefore, as a result of further research on the sealing structure in which the ceramic in the portion to be sealed of the translucent ceramic discharge vessel is heated and melted and welded to the current introduction conductor, the present inventors have found the following. In other words, cracks may occur in the sealing part in some cases, resulting in a problem that the translucent ceramic discharge vessel is broken or leaked, and the reliability and stability of sealing may be hindered. This is greatly influenced by the dimensional relationship between the small diameter cylindrical portion directly related to the sealing of the translucent ceramic discharge vessel, the current introduction conductor, and the sealing portion formed by these.

  The present invention relates to a sealing structure in which a portion to be sealed of a translucent ceramic discharge vessel is heated and melted and welded to a current introduction conductor. An object of the present invention is to provide a high-pressure discharge lamp, a high-pressure discharge lamp lighting device, and an illuminating device in which the dimensional relationship of the sealing portion is regulated within a predetermined range and cracks generated in the ceramic of the sealing portion are suppressed.

A high-pressure discharge lamp according to a first aspect of the present invention is a translucent ceramics discharge vessel provided with an enclosing part and a small-diameter cylindrical part connected to the enclosing part; and inserted into the small-diameter cylindrical part of the translucent ceramics discharge container A current introduction conductor sealed in the small diameter cylindrical portion mainly by fusion of ceramics in the small diameter cylindrical portion of the translucent ceramic discharge vessel; and connected to the current introduction conductor and sealed in the translucent ceramic discharge vessel And a discharge medium sealed in a translucent ceramic discharge vessel, and having a small diameter in the immediate vicinity of the sealed portion formed by sealing the current-introducing conductor by melting the ceramic in the small-diameter cylindrical portion. the cross-sectional area of the cylindrical portion to the _{S T,} when the cross-sectional area of the current introducing conductor and the _{S W,} formulas ratio _S W / _{S T} 1: 0.037 to satisfy ≦ _S W / _{S T} ≦ 0.363 It is characterized by.

  The present invention includes the following aspects.

  [Translucent Ceramic Discharge Vessel] The translucent ceramic discharge vessel is composed of a single crystal metal oxide such as sapphire and a polycrystalline metal oxide such as translucent airtight aluminum oxide, ie translucent polycrystalline alumina ceramics. , Yttrium-aluminum-garnet (YAG), yttrium oxide (YOX) and polycrystalline non-oxide, such as aluminum nitride (AlN), a light-transmitting and heat-resistant ceramic material, and discharge inside This is a container in which the space is formed airtight with respect to the outside. 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.

  Although this was unexpected, the present inventor has found that translucent ceramics can be melted relatively easily. The present invention has been made based on this discovery.

  In addition, the commonly used translucent polycrystalline alumina ceramics has an average crystal grain size of several tens of μm. In the present invention, at least crystals of a small-diameter cylindrical part or a part to be sealed thereof are used. Those having an average particle size of 4 μm or less are preferred. That is, when the average crystal grain size of the above portion is 4 μm or less, when sealing is performed by melting the ceramic of the small-diameter cylindrical portion, the familiarity with the introduction conductor is good, and the small-diameter cylindrical portion and the current are introduced by melting. During cooling after bonding with the conductor, cracks are unlikely to occur at the bonded 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 not generated at all by joining, which is optimal.

  In the embodiment in which the crystal average particle size of at least the small diameter cylindrical portion of the translucent ceramic discharge vessel is 4 μm or less, the portion where the crystal average particle size is 4 μm or less may be only the small diameter cylindrical portion. The entire translucent ceramics discharge vessel may be used. Further, if desired, the average crystal grain size may be 4 μm or less in some parts other than the small diameter cylindrical part.

  The translucency in the translucent ceramic discharge vessel 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 ceramics discharge vessel is provided with an enclosing portion in order 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.

  Moreover, the translucent ceramics discharge container is provided with the small diameter cylinder part connected to the surrounding part. The small-diameter cylindrical portion is a translucent ceramic discharge by inserting at least a current introduction conductor, which will be described later, and forming a sealing portion in cooperation with the current introduction conductor when the portion to be sealed is heated and melted. Functions to seal the container. And it is prescribed | regulated to the value from which the cross-sectional area nearest to the sealing part in a small diameter cylinder part becomes the predetermined relationship mentioned later. Moreover, it can be made to function also in order to enclose the discharge medium mentioned later in the inside of a translucent ceramics discharge container, ie, an enclosure part.

  The number of the small-diameter cylindrical portions is two for the configuration of sealing a general pair of electrodes, but it should be one to three or more depending on the number of current introduction conductors to be arranged. Allow. When two openings are provided to seal a pair of electrodes, each small-diameter cylindrical portion is provided at a position spaced apart from each other, but preferably is spaced apart from each other along the tube axis. In addition, the ceramic which comprises a small diameter cylinder part may be light-shielding.

  In the present invention, the small diameter cylindrical portion may or may not form a capillary structure inside. Therefore, the length of the small diameter cylindrical portion is not particularly limited in the present invention. In short, it is only necessary to have a length at which it is easy to form a sealing portion with at least the current introduction conductor by melting the ceramic of the small diameter cylindrical portion. The length of the small-diameter cylindrical portion described above can be clearly shorter than the length of the small-diameter cylindrical portion in the case of sealing using conventional frit glass.

In order to seal the translucent ceramic discharge vessel, the means for melting the ceramic of the small diameter cylindrical portion is not particularly limited in the present invention. For example, if the ceramic in the small-diameter cylindrical portion is heated and the temperature is raised above its melting temperature, the ceramic can be melted and adapted to the surface of the current introduction conductor inserted in the small-diameter cylindrical portion. Then, if heating is stopped and the familiar part is cooled, the ceramic is solidified, the current introduction conductor is sealed in the opening, and the small diameter cylindrical part is sealed. As a means for heating the ceramic in the small diameter cylindrical portion, 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, an electric heater, or the like 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 sealing target portion of the small-diameter cylindrical portion using the local heating means of the heat ray projection type, the local heating means is fixed to a predetermined separation position with respect to the planned portion, for example, the side of the planned portion. If either one or both of the small-diameter cylindrical portion and the local heating means of the translucent ceramic discharge vessel are rotated while operating the local heating means, the entire circumference of the small-diameter cylindrical portion can be heated uniformly. However, if desired, the laser is irradiated from the extending direction of the small-diameter cylindrical portion, for example, the tube axis direction, a plurality of local heating means are arranged around the small-diameter cylindrical portion fixedly arranged, or the local heating means is The light-transmitting ceramic discharge vessel 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 discharge vessel, the surrounding portion may be formed by integrally molding, or may be formed by joining or fitting a plurality of constituent members. Good. For example, when an incidental structure such as a small-diameter cylindrical portion is provided in addition to the surrounding portion, the incidental structure can be integrally formed from the beginning at both ends or one end of the surrounding portion. However, it is also possible to form an integral translucent ceramic discharge vessel by, for example, pre-sintering the surrounding portion and the incidental structure separately from each other and then joining them as required to sinter 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 the current introduction conductor] The current introduction conductor functions to apply voltage to the electrode described later, supply current to the electrode, and seal the translucent ceramic discharge vessel in cooperation with the small diameter cylindrical portion. Conductor. Therefore, the tip side portion inserted into the small diameter cylindrical portion of the translucent ceramic discharge vessel is connected to the electrode, and the base end side is exposed to the outside of the translucent ceramic discharge vessel. Further, the cross-sectional area of the current introduction conductor in the immediate vicinity of the sealing portion formed in cooperation with the small-diameter cylindrical portion is defined as a predetermined value described later. In addition, in the above, being exposed to the outside of the translucent ceramic discharge vessel may or may not protrude from the translucent ceramic discharge vessel, but power can be supplied from the outside. It only needs to face the outside.

Next, the cross-sectional area immediately adjacent to the sealed portion of the current introduction conductor will be described. In the present invention, the cross-sectional area as S _T, when the most recent cross-sectional area sealed portion in the ceramics of the small-diameter cylindrical portion of the above was S _W, the ratio S _{W /} S _T is Formula 1: 0.037 ≦ S _W / S _T ≦ 0.363 is satisfied. The cross-sectional area of the current introduction conductor that satisfies this condition is smaller than the cross-sectional area of the current introduction conductor that has been used in the conventional sealing structure using frit glass. For this reason, even if there is a difference in the coefficient of thermal expansion between the ceramics of the small-diameter cylindrical portion and the current introduction conductor, the stress generated due to the difference is reduced and the generation of cracks is suppressed. However, if the current introduction conductor becomes too thin, the current-carrying resistance of the current introduction conductor becomes so large that it cannot be ignored, and power loss due to heat generation occurs, so it must be within the above range. It should be noted that the position closest to the sealing portion is a position that is separated from the end of the sealing portion by about 0.2 to 1 mm in the tube axis direction and faces a portion of the same material as that of the sealing portion of the current introduction conductor. is there.

The general and preferred current-introducing conductor diameters when the cross-sectional area is defined so as to satisfy Equation 1 as described above are as follows. That is,
1. When the rated lamp power is 800 W or less, the diameter of the current introduction conductor is 2.5 mm or less, preferably 1.8 mm or less.
2. Similarly, in the case of 400 W or less, it is 1.5 mm or less, preferably 1.2 or less.
3. In the case of 100 W or less, it is 0.5 mm or less, preferably 0.5 mm or less.

  By the way, the current introduction conductor can be configured using a sealing metal or cermet.

  Sealing metals include niobium (Nb) and tantalum (Ta), which are conductive metals whose thermal expansion coefficient approximates that of translucent ceramics constituting the small-diameter cylindrical portion of translucent ceramic discharge vessel. ), Titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), platinum (Pt), molybdenum (Mo), tungsten (W), or a metal such as cermet can be used. Also, when aluminum oxide such as translucent polycrystalline alumina ceramics is used as the material of translucent ceramic discharge vessel, niobium and tantalum have the same average thermal expansion coefficient as aluminum oxide, and molybdenum Since the average coefficient of thermal expansion 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 discharge vessel, 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 of the metal selected from the above group may be used, and a cermet may be joined to the metal part in the tube axis direction or may be joined in the circumferential direction orthogonal to the tube axis. And when using a cermet for at least one part of a current introduction conductor, the small diameter cylinder part of a translucent ceramics discharge container and a current introduction conductor can be performed in the said cermet part.

  As the cermet, a ceramic material of which is made of, for example, alumina ceramics, and one or more kinds of metals selected from the above group, for example, molybdenum or tungsten can be used. Further, the cermet portion sealed in the translucent ceramic discharge vessel 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 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 the translucent ceramic discharge vessel generally does not absorb heat. Hard to occur. On the other hand, heat absorption increases on the cermet surface, and as a result, the surface of the cermet is heated and the temperature rises. To do.

  Moreover, 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 discharge vessel, and the high-pressure discharge is compared with the case where the translucent ceramic discharge vessel is in direct contact with molybdenum. Damage and leakage due to heat shock when the lamp is turned on are less likely to occur.

  If the said cermet is taken from the following viewpoints different from the above, it is preferable that the content rate of a metal component is 50-80 mass%.

That is, from the viewpoint of placing importance on the conductivity of the cermet, sufficient conductivity can be obtained if the content ratio of the metal component is within the above range. And if a cermet is the above structures, even if it is a cermet which has required electroconductivity, since the diameter can be made small, the sealing by this invention becomes still easier.

  However, if the content of the metal component exceeds 80% by mass, the difference in coefficient of thermal expansion from the translucent ceramic discharge vessel becomes too large, making it difficult to obtain a desired seal. Moreover, when the content of the metal component is 50% by mass, it is somewhat difficult to obtain desired conductivity.

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

  Further, if desired, at least the cermet in the portion to be sealed is located, the first cermet having mainly good sealing properties is located on the outer peripheral side, and the second cermet having mainly good conductivity is located on the center side. An inclined structure can also be used. In this case, the first and second cermets can be stepped or steplessly tilted.

  Furthermore, the current introduction conductor mainly has a function of a portion that is sealed to the small-diameter cylindrical portion of the translucent ceramic discharge vessel 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, formed in a different size or structure, and connected to form a current introduction conductor. I can do it. For example, it is known that a portion sealed mainly to a small-diameter cylindrical portion of a translucent ceramic discharge vessel is a cermet, and a portion mainly supporting an electrode is formed 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.

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

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

  [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 discharge vessel is exposed to the atmosphere. However, if necessary, the translucent ceramic discharge vessel 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.

A high pressure discharge lamp according to a second aspect of the present invention is a translucent ceramics discharge vessel provided with an enclosing part and a small diameter cylindrical part connected to the enclosing part; and inserted into the small diameter cylindrical part of the translucent ceramics discharge container A current introduction conductor sealed in the small diameter cylindrical portion mainly by melting of the ceramic in the small diameter cylindrical portion of the translucent ceramic discharge vessel; and connected to the current introduction conductor and sealed in the translucent ceramic discharge vessel An electrode; and a discharge medium sealed in a translucent ceramic discharge vessel; and the maximum outer diameter of the sealed portion formed by sealing the current-introducing conductor by melting the ceramic in the small-diameter cylindrical portion is φ in _S, the length and _{L S,} when the outer diameter of the small diameter cylinder portion at the nearest sealing portion was phi _T, the ratio φ _S / φ _T (%) is equation _{2: 100 ≦ φ S / φ} T ≦ 200 satisfied, and the ratio _{L S} / _{φ T} ( ) Formulas 3: a _{100 ≦ L S / φ T ≦} 300 , characterized in that.

In the present invention, the generation of cracks during sealing is suppressed by defining the size ratio of the size of the sealing portion.
The size of the sealing portion varies depending on the diameter and thickness of the small diameter cylindrical portion, the heating time at the time of sealing, the heating region, the heating means, the heating method, and the like. Therefore, in order to form the sealing portion so as to fall within the range defined by the present invention, the above parameters may be appropriately selected and sealed. For example, the part to be sealed is locally heated by laser irradiation, and at that time, the laser and the translucent ceramic discharge vessel are relatively placed, preferably the translucent ceramics discharge vessel is 10 to 500 revolutions / minute, preferably 100. It is rotated at a rate of ˜300 revolutions / minute, and further, the laser output is adjusted as necessary to melt the ceramics to be sealed.

A sealing part that can be lit can be obtained as long as both the numerical formula 2: 100 ≦ φ _S / φ _T ≦ 200 and the numerical formula 3: 100 ≦ L _S / φ _T ≦ 300 are satisfied. Then, the sealing part which can be lighted cannot be obtained. In the heat sealing step, when the relative rotation of the laser and the translucent ceramic discharge vessel is performed, if the number of rotations becomes too high, the sealing portion becomes too short and deviates from the lower limit of Equation 3. Cracks are likely to occur.

  In the present invention, as to other configurations, the configurations described in regard to the first invention can be appropriately adopted as desired.

    Next, a high pressure discharge lamp lighting device according to the present invention includes the high pressure discharge lamp according to the present invention; and a lighting circuit for lighting the high pressure discharge lamp.

  In the present invention, the lighting circuit may have any configuration. Moreover, any lighting system of AC lighting and DC lighting may be used. In the case of AC lighting, for example, an electronic lighting circuit mainly composed of an inverter can be configured. If desired, a DC-DC converter circuit such as a step-up chopper or a step-down chopper can be added to a DC power source connected between the input terminals of the inverter. In the case of DC lighting, for example, an electronic lighting circuit mainly composed of the above-described DC-DC conversion circuit can be configured.

    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 first and second inventions, in the sealing structure in which the part to be sealed of the translucent ceramic discharge vessel is heated and melted and welded to the current introduction conductor, the small diameter cylindrical part in the part to be sealed, the current introduction It is possible to provide a high-pressure discharge lamp, a high-pressure discharge lamp lighting device, and an illuminating device in which the dimensional relationship between the conductor and the sealing portion formed by the conductor is defined within a predetermined range and cracks generated in the ceramic of the sealing portion are suppressed. .

Further, according to the first invention, by defining the sectional area S _W of the cross-sectional area S _T and the current introducing conductor ceramics of the small-diameter cylindrical portion within a range satisfying the equation 1, the cross-sectional area of the current introducing conductor Therefore, since the stress generated based on the difference in coefficient of thermal expansion between the current introduction conductor and the ceramic fused to the current introduction conductor becomes small, it is possible to suppress cracks generated in the ceramic of the sealing portion. On the other hand, since the cross-sectional area of the current introduction conductor is set in a range in which the current introduction conductor is not too small, the power loss generated in the current introduction conductor does not increase excessively when the lamp current flows through the current introduction conductor.

Further, according to the second invention, the maximum outer diameter φ _S , the length L _S and the current introduction conductor outer diameter of the formed sealing portion are defined within the ranges satisfying both Expression 2 and Expression 3. The diameter of the current-introducing conductor can reduce the stress at the time of sealing and effectively suppress the generation of cracks, and can reduce the size of the sealing portion and contribute to the miniaturization of the entire high-pressure discharge lamp.

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

    1 to 4 show a metal halide lamp for an automobile headlamp as a first embodiment of the high-pressure discharge lamp of the present invention, FIG. 1 is a front view of the entire lamp, and FIG. 2 is an enlarged sectional view of an arc tube, FIG. 3 is a front view showing an example of the appearance of the sealing portion of the arc tube, and FIG. 4 is an enlarged cross-sectional view of the main part of the arc tube. The metal halide lamp MHL for automobile headlamps is mainly composed of a luminous tube IT, lead wires L1 and L2, an insulating tube T, an outer tube OT, and a base B.

  The arc tube IT includes a translucent ceramic discharge vessel 1, a current introduction conductor 2, an electrode 3, and a discharge medium, and has a sealing portion SP.

As shown in FIG. 2, the translucent ceramic discharge vessel 1 is formed by integral molding using translucent ceramic as a main material, and includes an enclosing portion 1a and a pair of small-diameter cylindrical portions 1b and 1b. The surrounding portion 1a is formed into a hollow spindle 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 0.05 cc or less. The pair of small-diameter cylindrical portions 1b and 1b are formed by relatively short and thin cylindrical portions that are integrally extended from both ends of the surrounding portion 1a in the tube axis direction. And the sealing part SP is formed in the scheduled sealing part. Further, the cross-sectional area in the immediate vicinity of the sealing portion SP is set so as to satisfy the formula 1 (0.037 ≦ S _W / S _T ≦ 0.363).

As shown in FIGS. 3 and 4, the sealing portion SP mainly melts the ceramic of the small-diameter cylindrical portion 1b and contracts in the tube axis direction due to surface tension, and expands or contracts in a direction perpendicular to the tube axis. It has an unusual shape. Further, the sealing portion SP often forms a solid solution by dissolving the constituent material of the current introduction conductor 2 described later in the ceramic, and in this case, the color changes to a color different from the intrinsic color of the ceramic. Yes. Furthermore, the size of the sealing part SP is as follows, and both the mathematical formulas 2 and 3 are satisfied. That is, the maximum outer diameter is phi _S, the length of the tube axis direction is indicated by L _S. The diameter of the small-diameter cylindrical portion 1b in the immediate vicinity of the sealing portion SP is indicated by phi _T.

  The current introduction conductor 2 is made of a cermet, a niobium rod, or the like, inserted into each small-diameter cylindrical portion 1b of the translucent ceramic discharge vessel 1, and sealed by melting at least the ceramic in the small-diameter cylindrical portion 1b. In the illustrated form, the current introduction conductor 2 is composed of a series joined body of a niobium part 2a, a cermet part 2b, and a molybdenum part 2c. The niobium part 2a is located on the proximal end side of the current introduction conductor 2, the molybdenum part 2c is located on the distal end side, and the cermet part 2b is located in the middle. And the sealing part SP is formed in the site | part straddling the niobium part 2a and the cermet part 2b. In the illustrated embodiment, the closest position of the sealing portion SP is a portion that is spaced from the end of the sealing portion SP by about 0.2 to 1 mm in the tube axis direction and that faces the cermet portion 2b.

  Therefore, the distal end portion of the current introduction conductor 2 is inserted into the small diameter cylindrical portion 1 b and the proximal end portion is exposed to the outside of the translucent ceramic discharge vessel 1. When the small diameter cylindrical portion 1b is heated and sufficiently melted when the current introduction conductor 2 is sealed, the small diameter cylindrical portion 1b expands in the radial direction while condensing in the axial direction due to surface tension, as shown in FIGS. There is a tendency to form a sealing portion SP that is deformed into an oval or teardrop shape.

  The electrode 3 is made of a tungsten wire, 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 discharge vessel 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 short in the tube axis direction, that is, a capillary, is formed between the intermediate portion of the electrode 3 and the inner surface of the small-diameter cylindrical portion 1b. However, this capillary can be clearly shortened compared to that in a conventional high-pressure discharge lamp in which a translucent ceramic discharge vessel is sealed using frit glass.

  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 voltage forming halide is a metal halide having a high vapor pressure and a small amount of luminescence in the visible region in the coexistence with the luminescent metal halide compared to the luminescent metal.

  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 is folded back along an outer tube OT described later, 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 outer tube OT has an ultraviolet ray cutting performance, accommodates the arc tube IT therein, and the diameter-reduced portions 4 at both ends (only one end on the right side is shown in the figure) are connected to the lead wire L2. Glass welded. However, the inside of the outer tube OT is not airtight but communicates with the outside air.

  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.

Example 1 is a high-pressure discharge lamp shown in FIGS. 1 to 3.
Translucent ceramic discharge vessel: Made of integral translucent alumina ceramic,
Enclosure: Maximum inner diameter 6mm, Maximum inner diameter 5mm, Wall thickness 0.5mm,
Small diameter cylindrical part: 2.7mm outer diameter, 0.7mm inner diameter, 5mm length
Current-introducing conductor: Mo-Al ₂ O ₃ = 50: 50% by volume cermet rod, diameter 0.65mm
Electrode: 3mm distance between electrodes
Discharge medium: DyI ₃ -NdI ₃ -CsI = 3mg, Xe0.5 bar rated lamp power: 35W

Translucent ceramic discharge vessel: Made of integral translucent alumina ceramic,
Enclosure: Maximum inner diameter 6mm, Maximum inner diameter 5mm, Wall thickness 0.5mm,
Small diameter cylindrical part: Outer diameter 1.7mm, Inner diameter 0.4mm, Length 5mm
Current-introducing conductor: Mo-Al ₂ O ₃ = 50: 50% by volume cermet rod, diameter 0.35mm
Other specifications are the same as those in the first embodiment.

    FIG. 5 is a graph showing the relationship between the cross-sectional area ratio, crack generation rate, and power loss generation rate in the immediate vicinity of the small-diameter cylindrical portion and the sealed portion of the current introduction conductor. In the figure, the ratio of the cross-sectional area of the sealing body on the horizontal axis shows the ratio of the cross-sectional area in the immediate vicinity of the small-diameter cylindrical part and the sealing part of the current introduction conductor. The loss rate% (■) is shown respectively.

  As can be understood from the drawing, if the cross-sectional area ratio (ratio of the cross-sectional area of the sealing body) in the immediate vicinity of the small-diameter cylindrical portion and the sealing portion of the current introduction conductor is within the range of 0.037 to 0.363, cracks are generated. Both the rate and the power loss occurrence rate are significantly reduced. In the above, the power loss means that a power loss of 1% or more with respect to the lamp power is generated in the current introduction conductor due to a shortage of a cross-sectional area of the current introduction conductor, resulting in a heat loss. Therefore, the power loss occurrence rate indicates a rate at which heat generation defects that cannot be ignored due to the current introduction conductor being too thin are generated.

  In order to obtain practical lamp performance, the efficiency decreases due to heat loss and the increase in the amount of impurities accompanying the increase in the amount of discharge medium encapsulated (by determining the amount of entrapment in anticipation of the discharge medium staying in the small diameter cylinder) It is necessary to suppress start-up failure, short life, and characteristic instability. For this reason, a small diameter cylinder part cannot be made large diameter too much. Therefore, the smaller the ratio of the cross-sectional area of the sealed conductor on the horizontal axis in FIG. 6, the smaller the cross-sectional area of the current introduction conductor, in particular, the cross-sectional area of the sealed conductor that is the current introduction conductor portion in the sealing portion. Become a trend. If the cross-sectional area of the current introduction conductor, especially the sealing conductor, becomes smaller than a certain range with respect to the rated lamp current for each lamp specification, the resistance heat generation in the current introduction conductor will clearly raise the temperature of the current introduction conductor due to the temperature rise. It becomes like this. Then, even though the resistivity of the current introduction conductor rapidly increases due to the temperature rise, almost the same lamp current flows, so that the resistance heat generation further increases, and the temperature of the current introduction conductor is further increased. As a result, a chain cycle in which the resistance heat generation further increases and the temperature rises further occurs. As a result, as shown in the region on the left side of the curve (square) in FIG. A phenomenon in which heat generation (power loss) suddenly increases occurs.

FIG. 7 shows the results of a lighting test in which a high-pressure discharge lamp was manufactured by changing the maximum outer diameter and length of the sealing portion, which is the size of the sealing portion, and the outer diameter of the small-diameter cylindrical portion in the immediate vicinity of the sealing portion. It is a graph to show. In the figure, the horizontal axis represents the ratio φ _S / φ _T , and the vertical axis represents the ratio L _S / φ _T.

As can be understood from the figure, if the ratio φ _S / φ _T is within the range of 100 to 200 (%) and the ratio L _S / φ _T is within the range of 100 to 300%, the sealing is good and the lamp can be lit. When deviating from the above range, lighting is impossible.

    FIG. 7 is a block circuit diagram showing an embodiment of the high pressure discharge lamp lighting device of the present invention. The high pressure discharge lamp lighting device of the present invention includes the high pressure discharge lamp MHL of the first or second aspect of the present invention and a lighting circuit for lighting the high pressure discharge lamp MHL. In this embodiment, the lighting circuit employs a low-frequency AC lighting circuit system.

  In this embodiment, the lighting circuit is digitized and includes a DC power source DC, a boost chopper BUT, a full bridge inverter FBI, and an igniter IG, and lights a metal halide lamp MHL for an automobile headlamp.

  The DC power source DC is composed of, for example, a car battery.

  The input terminal of the boost chopper BUT is connected to the DC power source DC.

  The full bridge type inverter FBI has its input terminal connected to the output terminal of the boost chopper BUT.

  The igniter IG receives a low-frequency AC output from the full-bridge inverter FBI, generates a high-voltage start pulse, and applies it between a pair of electrodes of a metal halide lamp MHL for an automobile headlamp described later at the start.

  The metal halide lamp MHL for automobile headlamps has the configuration shown in FIGS. 1 and 2, and is connected between the output terminals of the full bridge inverter FBI to be lit at a low frequency.

    FIG. 8 is a conceptual side view showing an automobile headlamp as an embodiment of 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 the circuit configuration shown in FIG. 7, 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 1st Embodiment in the high pressure discharge lamp of this invention Similarly enlarged sectional view of arc tube Similarly, a front view showing an example of the appearance of the sealed portion of the arc tube Similarly enlarged sectional view of arc tube A graph showing the relationship between the cross-sectional area ratio, crack occurrence rate, and power loss occurrence rate in the immediate vicinity of the small diameter cylindrical portion and the sealed portion of the current introduction conductor A graph showing the results of lighting tests after manufacturing a high-pressure discharge lamp in which the maximum outer diameter and length of the sealing part, which is the size of the sealing part, and the outer diameter of the small-diameter cylindrical part in the immediate vicinity of the sealing part were changed. The block circuit diagram which shows one Embodiment in the high pressure discharge lamp lighting device of this invention The conceptual side view which shows the motor vehicle headlamp as one Embodiment in the illuminating device of this invention

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Translucent ceramics discharge container, 1a ... Enveloping part, 1b ... Small diameter cylinder part, 2 ... Current introduction conductor, IT ... Arc tube, SP ... Sealing part

Claims (5)

A translucent ceramics discharge vessel comprising a surrounding portion and a small diameter tubular portion formed connected to the surrounding portion;
A current-introducing conductor inserted into the small-diameter cylindrical portion of the translucent ceramic discharge vessel and sealed to the small-diameter cylindrical portion mainly by fusion of ceramics in the small-diameter cylindrical portion of the translucent ceramic discharge vessel;
An electrode connected to a current introducing conductor and sealed in a translucent ceramic discharge vessel;
A discharge medium enclosed in a translucent ceramic discharge vessel;
Comprises a, in the immediate vicinity of the sealing portion formed by sealing the current introducing conductor by melting ceramics of the small-diameter tubular portion, the cross-sectional area of the ceramic of the small diameter cylinder portion and S _T, the cross-sectional area of the current introducing conductor when the S _W, the ratio _S W / _{S T} is formula _{1: 0.037 ≦ S W / S} T ≦ 0.363 pressure discharge lamp which satisfies the.   The current introduction conductor has a diameter of 2.5 mm or less for a rated lamp power of 800 W or less, 1.5 mm or less for 400 W or less, and 0.5 mm or less for 100 W or less. Item 6. The high-pressure discharge lamp according to Item 1. A translucent ceramics discharge vessel comprising a surrounding portion and a small diameter tubular portion formed connected to the surrounding portion;
A current-introducing conductor inserted into the small-diameter cylindrical portion of the translucent ceramic discharge vessel and sealed to the small-diameter cylindrical portion mainly by melting of the ceramic in the small-diameter cylindrical portion of the translucent ceramic discharge vessel;
An electrode connected to a current introducing conductor and sealed in a translucent ceramic discharge vessel;
A discharge medium enclosed in a translucent ceramic discharge vessel;
A small diameter cylinder in the immediate vicinity of the sealing portion, wherein the maximum outer diameter of the sealing portion formed by sealing the current introduction conductor by melting of the ceramic in the small diameter cylindrical portion is φ _S and the length is L _S When the outer diameter of the portion is φ _T , the ratio φ _S / φ _T (%) satisfies Formula 2: 100 ≦ φ _S / φ _T ≦ 200, and the ratio L _S / φ _T (%) is expressed by Formula 3. : 100 ≦ L _S / φ _T ≦ 300 A high-pressure discharge lamp according to any one of claims 1 to 3;
A lighting circuit for lighting the high-pressure discharge lamp;
A high-pressure discharge lamp lighting device comprising: 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:

Images