JP2008103320A - High-pressure discharge lamp, high-pressure discharge lamp lighting device, and illuminating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-pressure discharge lamp in which sealing performance is remarkably improved by sealing between a translucent ceramic discharge vessel and current introducing conductors without using a frit glass, and a high-pressure discharge lamp lighting device and an illuminating apparatus using the high-pressure discharge lamp. <P>SOLUTION: The high-pressure discharge lamp MHL comprises: the translucent ceramic discharge vessel 1 equipped with a surrounding part 1a and small diameter cylindrical parts 1b of which lengths formed by being connected to the surrounding part are each 10 mm or less with respect to a rated lump power of 800 W or less, and each 7 mm or less with respect to the rated lump power of 100 W or less; the current introducing conductors 2 inserted inside the small diameter cylindrical parts and sealed to the small diameter cylindrical parts mainly by fusion of ceramics in the small diameter cylindrical parts; electrodes 3 connected to the current introducing conductors and sealed, mounted inside the translucent ceramic discharge vessel; and a discharge medium sealed into the translucent ceramic discharge vessel. <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.

  The present invention relates to a high pressure discharge lamp, a high pressure discharge lamp lighting device, and an improved sealing structure of a translucent ceramic discharge vessel, in which the problems caused by sealing with a glass frit in the prior art are suppressed. An object is to provide a lighting device.

  The present invention relates to a high pressure discharge lamp in which the sealing performance is remarkably improved by sealing between a translucent ceramic discharge vessel and a current introduction conductor without using frit glass, and a high pressure discharge lamp lighting device and an illumination device using the same. The other purpose is to provide.

    The high-pressure discharge lamp of the present invention includes a surrounding portion and a transparent tube portion having a small diameter cylindrical portion that is connected to the surrounding portion and has a length of 10 mm or less for a rated lamp power of 800 W or less and 7 mm or less for 100 W or less. A light ceramic discharge vessel; an electric current inserted in 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 introduction conductor; an electrode connected to the current introduction conductor and sealed in a translucent ceramic discharge vessel; and a discharge medium enclosed in the translucent ceramic discharge vessel. .

  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 functions to seal the translucent ceramic discharge vessel by inserting at least a current introducing conductor, which will be described later, 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 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.

  The small-diameter cylindrical part is separate when the translucent ceramic discharge vessel is formed, but after sealing together with the current introduction conductor, a cylindrical intermediate member integrated as a small-diameter cylindrical part is added. Can be used. That is, not only is the portion of the small-diameter cylindrical portion formed integrally when the translucent ceramic discharge vessel is formed and the current introduction conductor directly fused to form a seal, but also the translucent ceramic A cylindrical intermediate member made of ceramics or the like can be interposed between the small-diameter cylindrical portion integrated with the discharge vessel and the current introduction conductor. This intermediate member is allowed to be in a cylindrically solidified state or a powder state. The intermediate member is fused to the small-diameter cylindrical portion and the current introduction conductor to satisfactorily seal between them. If the average crystal grain size of the intermediate member is 4 μm or less, the familiarity between the current-introducing conductor and the small-diameter cylinder portion is obtained even if the average crystal grain size of the small-diameter cylindrical portion integrated with the translucent ceramic discharge vessel is not 4 μm or less. Is better. In this case, needless to say, the small diameter cylindrical portion may have an average crystal grain size of 4 μm or less.

  In the present invention, the length of the small-diameter cylindrical portion is specified to be 10 mm or less for a high-pressure discharge lamp having a rated lamp power of 800 W or less and 7 mm or less for 100 W or less. However, in order to heat the ceramic of the small-diameter cylindrical portion so as to be easily fused to the current introducing conductor, the length of the small-diameter cylindrical portion is at least about 1 mm, preferably 1.5 mm or more. The length of the small-diameter cylindrical portion is preferably 1.5 to 8.5 mm for 800 W or less, and 1.5 to 5.5 mm for 100 W or less. Furthermore, in order to obtain a high-pressure discharge lamp in which a capillary structure is formed inside the small-diameter cylindrical portion, the small-diameter cylindrical portion is preferably 4 mm or more. The length of the small-diameter cylindrical portion described above is clearly shorter than the length of the small-diameter cylindrical portion in the case of sealing using conventional frit glass. If the length of the small-diameter cylindrical portion is within the above range, the amount of discharge medium enclosed is reduced, and accordingly, the amount of impurities mixed in the discharge medium is reduced, thereby suppressing the occurrence of blackening. Can do. On the other hand, when the length of the small-diameter cylindrical portion exceeds the above upper limit value, the required enclosed amount of the discharge medium increases. Therefore, not only does the amount of blackening increase with the increase in the amount of discharge medium enclosed, but the longer the small-diameter cylindrical part, the lower the mechanical strength and the difficulty in obtaining a compact high-pressure discharge lamp. Become. When the surrounding portion and the small-diameter cylindrical portion are continuous via a curved surface, the distal end of the small-diameter cylindrical portion on the side of the surrounding portion is between the inner surface of the translucent ceramic discharge vessel and the outer surface of the shaft portion of the electrode facing the inner surface. Is assumed to be at a position of 0.5 mm. When the gap is 0.5 mm or less, a capillary structure suitable for controlling the coldest part temperature can be formed by the liquid phase discharge medium entering the inside of the small-diameter cylindrical part by capillary action.

  In the present invention, the reason for limiting the length of the small-diameter cylindrical portion to the above numerical value is as follows. In other words, when the current-introducing conductor is sealed by fusing ceramics in the small-diameter cylindrical part, it is not necessary to use frit glass. Are equivalent or improved. For this reason, even if the small-diameter cylindrical portion is short, at least substantially the same life as a conventional high-pressure discharge lamp sealed with frit glass can be obtained. Further, by shortening the small-diameter cylindrical portion, the following effects can be obtained.

  In the case of sealing a light-transmitting ceramic discharge vessel using a conventional frit glass, a so-called capillary structure is adopted for the small-diameter cylindrical portion because the heat resistant temperature of the frit glass is low. In the present invention, frit glass is not used, but it is preferably formed in order to control the coldest part temperature using a capillary structure. However, the capillary structure may not be provided if desired. In the case of this configuration, the length of the small-diameter cylindrical portion can be made extremely small, so that the translucent ceramics discharge vessel can be made more compact.

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 is melted and can be adapted to the surface of the current introduction conductor inserted in the small-diameter cylindrical portion. Then, if the 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. The means for heating the ceramic of the small diameter cylindrical portion 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 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. Then, if 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 uniformly heated. 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 translucent ceramic discharge vessel can be heated in a stationary state by rotating around the small-diameter cylindrical portion or by providing 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.

  [Regarding Current Induction Conductor] The current introduction 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 discharge vessel. 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. The term “exposed to the outside of the translucent ceramic discharge vessel” means that it may or may not protrude from the translucent ceramic discharge vessel. You just have to face.

  The current introduction conductor is a sealing metal, that is, niobium (Nb), which is a conductive metal whose thermal expansion coefficient is similar to that of the translucent ceramic constituting the small-diameter cylindrical portion of the translucent ceramic discharge vessel. ), Tantalum (Ta), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), platinum (Pt), molybdenum (Mo), tungsten (W), or other metals or cermets Can do. 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.

  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 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 coefficient of thermal expansion with the translucent ceramics discharge vessel becomes too large, making it difficult to obtain a desired seal. Moreover, when content of a metal component will be 50 mass%, it will become difficult to obtain desired electroconductivity.

  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 sealing of the inside of the translucent ceramic discharge vessel from the outside. Also, since niobium and the like are highly oxidative, when a 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 discharge vessel 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 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 or formed in a different size and structure, and they are connected to form a current introduction conductor. You can do it. For example, it is known that a portion mainly sealed with a small diameter cylindrical portion of a translucent ceramic discharge vessel 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 small-diameter cylindrical 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. You may do it.

Next, sealing means between the small-diameter cylindrical portion of the translucent ceramic discharge vessel and the current introduction conductor will be described. The present invention includes the following aspects. In any embodiment, the sealing is formed by fusing the small-diameter cylindrical portion ceramics of the translucent ceramic discharge vessel. Therefore, there is a common point that a material component different from the material of the translucent ceramic discharge vessel such as frit glass in the prior art and the current introduction conductor of the sealing portion, for example, SiO ₂ , Dy ₂ O ₃ or the like is not interposed. Exists.
(1) A mode in which the ceramic in the small-diameter cylindrical portion of the translucent ceramic discharge vessel is mainly fused to the current introduction conductor.
(2) A mode in which a portion of the current introducing conductor facing the small-diameter cylindrical portion of the translucent ceramic discharge vessel is mainly fused.
(3) A mode in which the ceramic and the current introduction conductor of the small-diameter cylindrical portion of the translucent ceramic discharge vessel are fused together to form a solid solution.
(4) A mode in which the sealing material of the same quality as the material of the portion of the translucent ceramic discharge vessel facing the small diameter tube portion of the translucent ceramic discharge vessel of the translucent ceramic discharge vessel is 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.

  [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.

  The required sealed amount of the discharge medium will be described. When the light-transmitting ceramic hermetic container includes a small-diameter cylindrical portion that communicates with the surrounding portion, an excessive discharge medium stays in the liquid-phase state inside the small-diameter cylindrical portion during lighting of the high-pressure discharge lamp. For this reason, it is necessary to enclose significantly more discharge medium than the amount contributing to the discharge. The coldest part of the discharge is formed in the vicinity of the surface of the discharge medium staying in the small-diameter cylindrical part on the surrounding part side, and the temperature distribution along the length direction from the coldest part to the proximal end of the small-diameter cylindrical part is lowered. A gradient occurs. As a result, the temperature of the sealing portion formed on the proximal end side of the small diameter cylindrical portion is maintained within the allowable temperature range. For this reason, by setting the length of the small-diameter cylindrical portion to an appropriate value, the translucent ceramic discharge vessel can be sealed with frit glass having a relatively low heat-resistant temperature.

  However, even in the sealing structure according to the present invention that does not use frit glass for sealing the translucent ceramic discharge vessel, the discharge medium is in a liquid phase state in the small-diameter cylindrical portion by including the small-diameter cylindrical portion. It stays at. Therefore, it can be understood that the required enclosed amount of the discharge medium changes according to the length of the small-diameter cylindrical portion provided in the translucent ceramic discharge vessel. If the translucent ceramic discharge vessel does not have a small-diameter cylindrical portion, an excess portion of the discharge medium adheres in the liquid phase to the coldest portion generated on the lower portion of the surrounding portion and the inner surface near the electrode protruding portion. In this case, the amount of adhesion is as small as a fraction of that when a small-diameter cylindrical portion is provided. The required amount of discharge medium is affected by the length of the small-diameter cylindrical portion regardless of the rated lamp power of the 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 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.

    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 present invention, the current-introducing conductor is sealed to the small-diameter cylindrical portion by fusing the ceramic in the small-diameter cylindrical portion, and the length of the small-diameter cylindrical portion of the translucent ceramic discharge vessel is set to a rated lamp power of 800 W or less. By setting the length to 10 mm or less, it is possible to obtain life characteristics equivalent to those in the prior art in which the current-introducing conductor is sealed using a translucent ceramic discharge vessel and a frit glass having a small-diameter cylindrical portion increased in length. In addition to the following effects.

1. The amount of discharge medium enclosed can be reduced.
Since the amount of the liquid-phase discharge medium that enters a slight gap formed between the inner surface of the small-diameter cylindrical portion and the shaft portion of the electrode and / or the current introduction conductor inserted therethrough is reduced as compared with the prior art. Cost reduction can be achieved.

2. The amount of impurities that get mixed into the discharge medium is reduced.
When the amount of discharge medium enclosed is reduced, the amount of impurities mixed into the discharge medium is also reduced, so that startability is improved, white turbidity and blackening are reduced, the luminous flux maintenance factor is improved, and electrode wear is reduced. As a result, the cost of the high pressure discharge lamp can be reduced.

3. A compact high-pressure discharge lamp can be obtained.
When the small-diameter cylindrical portion is shortened, the total length of the translucent ceramic discharge vessel is remarkably reduced, so that a compact high-pressure discharge lamp can be obtained.

4). The scattering of the electrode material is reduced and the occurrence of blackening is suppressed.
Since the length of the current introduction conductor is shortened as the length of the small diameter cylindrical portion is reduced, the diameter of the electrode and the current introduction conductor for maintaining the desired electrode tip temperature can be reduced, and as a result The occurrence of blackening is suppressed by reducing the scattering of tungsten from the electrodes. In addition, cost can be reduced.

  5. By reducing the length of the small-diameter cylindrical portion of the translucent ceramic discharge vessel, the impact resistance and thermal shock resistance are further improved.

  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 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.

  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. The length L of the small-diameter cylindrical portion 1b is set to 10 mm or less with respect to the rated lamp power of 800 W or less and 7 mm or less with respect to 100 W or less.

  The current introduction conductor 2 is made of a sealing metal rod, is inserted into each opening 1b of the translucent ceramic discharge vessel 1, and is sealed by melting at least the ceramic in the small diameter cylindrical portion 1b. Accordingly, the distal end portion of the current introduction conductor 2 is located in the small diameter cylindrical portion 1 b and the proximal end portion is exposed to the outside of the translucent ceramic discharge vessel 1. In addition, when the current introduction conductor 2 is sealed, the small-diameter cylindrical portion 1b is heated and sufficiently melted, and is swelled in the radial direction while condensing in the axial direction due to surface tension, and deformed into an elliptical spherical shape or a teardrop shape. Tend to.

  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 is clearly shorter than that in a conventional high-pressure discharge lamp that uses frit glass to seal the translucent ceramic discharge vessel.

  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.

Translucent ceramic discharge vessel: Made of integral translucent alumina ceramic,
Enclosure; maximum inner diameter 6mm, wall thickness 0.5mm
Small-diameter cylindrical part: 0.7mm inner diameter, 0.5mm wall thickness, 5mm length
Current-introducing conductor: Mo—Al ₂ O ₃ = 50: 50 vol% cermet rod electrode: made of tungsten rod, welded to the tip of the current-introducing conductor.

Sealing method: The rotating opening is irradiated with a YAG laser from the outside to transmit light.
The current-introducing conductor was sealed to the small-diameter cylinder by welding the ceramics in the small-diameter cylinder of the conductive ceramic discharge vessel.
Rated lamp power: 35W

    FIG. 3 is a graph showing the relationship between the length of the small-diameter cylindrical portion, the discharge medium sealing amount, and the blackening generation amount in a high-pressure discharge lamp with a rated lamp power of 400 W.

    FIG. 4 is a graph showing the relationship between the small-diameter cylindrical portion length, the discharge medium sealing amount, and the blackening generation amount in a high-pressure discharge lamp with a rated lamp power of 70 W.

  3 and 4, the horizontal axis represents the length of the small-diameter cylindrical portion (mm), the vertical axis represents the discharge medium enclosure amount relative value (♦), which means the required enclosure amount of the discharge medium, and the right side represents blackening at the end of life The blackening relative value (■) indicating the quantity is shown respectively. In addition, evaluation about blackening can be performed by quantifying the measured value by the light transmittance of the surrounding part of the translucent ceramic discharge vessel 1, and surface reflected light brightness | luminance.

  As can be understood from both figures, as the length of the small-diameter cylindrical portion becomes shorter, the required amount of the discharge medium is reduced, and accordingly, the amount of blackening is also reduced. Therefore, in the rated lamp power 400W of FIG. 3, the length of the small-diameter cylindrical portion is 8.5 mm or less, and in the rated lamp power 70W of FIG. 4, if the length of the small-diameter cylindrical portion is 5.5 mm or less, This is effective because both the amount of discharge medium enclosed and the amount of blackening at the end of the life are remarkably reduced. The trend in FIG. 3 is the same for other rated lamp powers as long as the rated lamp power is 800 W or less, but a small diameter cylinder in which both the discharge amount of the discharge medium and the blackening at the end of the life start to decrease significantly. The length of the portion changes continuously in proportion to the lamp power. The same applies to FIG. The lengths at which the remarkably starts to be reduced are indicated by points A (100 W−vertical axis 5.5 mm) and point B (800 W) in the graph in which the horizontal axis is the rated lamp power (W) and the vertical axis is the length of the small-diameter cylindrical portion. -It almost coincides with a straight line connecting with the vertical axis (8.5 mm). Therefore, the preferable length of the small diameter cylindrical portion for each rated lamp power can be obtained based on the graph.

  Hereinafter, with reference to FIG. 5 thru | or FIG. 7, the other form for implementing the high pressure discharge lamp of this invention is demonstrated. In addition, in each figure, the same code | symbol is attached | subjected about the part same as FIG. 2, and description is abbreviate | omitted.

    FIG. 5 is a front sectional view of an arc tube according to a second embodiment for tying up the high-pressure discharge lamp of the present invention.

  In this embodiment, the current introduction conductor 3 having a diameter close to the inner diameter of the small-diameter cylindrical portion is inserted over almost the entire length inside the small-diameter cylindrical portion 1b, so that the capillary is not substantially formed. In the case of the illustration, the capillary is practically not formed at all. However, in the present invention, even if a slight gap is formed between the inner surface of the small diameter cylindrical portion and the electrode 2, the length is 3 mm or less. If it exists, since it does not have an effect | action as a capillary, it can be said that it is the structure by which a capillary is not substantially formed.

Example 2 is a high-pressure discharge lamp shown in FIG.
Translucent ceramic discharge vessel: Made of integral translucent alumina ceramic,
Enclosure; maximum inner diameter 6mm, wall thickness 0.5mm
Small diameter cylindrical part: 1.7mm inner diameter, 0.5mm wall thickness, 5mm length
Current-introducing conductor: Mo-Al ₂ O ₃ = 50: 50% by volume, 1.5 mm diameter cermet rod,

                            The small diameter cylindrical portion is inserted over almost the entire length.

Others are the same as in the first embodiment.

    FIG. 6 is a front sectional view of an arc tube according to a third embodiment for carrying out the high-pressure discharge lamp of the present invention, (a) is a translucent ceramic discharge vessel before sealing, and (b) is completed. It is sectional drawing of an arc tube.

  In this embodiment, as shown in (a), an exhaust pipe 1e is formed on the side surface of the surrounding portion 1a before sealing so as to communicate with the inside of the surrounding portion 1a. A chip-off portion 1d is formed. And after sealing a pair of small diameter cylinder parts 1b and 1b of translucent ceramics discharge vessel 1, after exhausting the inside of enclosure part 1a via exhaust pipe 1e, or in an inert gas atmosphere, The discharge medium is sealed in the surrounding portion 1a, and then the exhaust pipe 1e is heated and melted and sealed to form an exhaust tip-off portion 1d. In FIG. 6B, dimension A is the length of the current introduction conductor 3, dimension B is the length of the sealing portion, and dimension C is the length of the joined body of the current introduction conductor 2 and the electrode 2.

    FIG. 7 is a schematic cross-sectional view of an arc tube according to a fourth embodiment for implementing the high-pressure discharge lamp of the present invention.

  In this embodiment, an enclosing enclosure 1 f is provided on the upper end side of the translucent ceramic discharge vessel 1 before sealing. In (a) of the figure, after the current introduction conductor 3 joined to the electrode 2 is sealed in the small diameter cylindrical portion 1b on the lower end side, the current introduction conductor 3 joined to the electrode 2 is inserted from the upper end side, For example, it is temporarily fixed with frit glass. Then, in (b) of the figure, after enclosing the discharge medium, the enclosing enclosure 1f is first sealed. And the intermediate part located in the middle of the surrounding part 1a and the enclosure surrounding part 1f is melted and sealed as a small diameter cylindrical part 1b. Thereafter, in FIG. 5C, the enclosing enclosure portion 1f is cut off to obtain a high-pressure discharge lamp. By performing sealing in such a process, it is not necessary to perform a sealing operation in the exhaust chamber, and the sealing process can be facilitated.

    FIG. 8 is a block circuit diagram showing an embodiment for implementing the high pressure discharge lamp lighting device of the present invention. In this embodiment, the lighting circuit employs a low-frequency AC lighting circuit system. In the figure, DC is a DC power source, BUT is a step-up chopper, FBI is a full-bridge inverter, IG is an igniter, and MHL is a metal halide lamp for automobile headlamps.

  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. 9 is a conceptual side view showing an automobile headlamp as an embodiment for carrying out the lighting 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. 8, 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 The graph which shows the relationship between the small diameter cylinder length, the discharge medium enclosure amount, and the blackening generation amount in the high pressure discharge lamp with a rated lamp power of 400 W The graph which shows the relationship between the small diameter cylinder length, the discharge medium enclosure amount, and the blackening generation amount in the high pressure discharge lamp with a rated lamp power of 70 W Front sectional drawing of the arc tube in the 2nd form for implementing the high-pressure discharge lamp of the present invention It is front sectional drawing of the arc_tube | light_emitting_tube in the 3rd form for implementing the high pressure discharge lamp of this invention, (a) is the translucent ceramics discharge container before sealing, (b) is the cross section of the completed arc tube. Figure Schematic sectional view of an arc tube according to a fourth embodiment for implementing the high-pressure discharge lamp of the present invention The block circuit diagram which shows one form in order to implement the high pressure discharge lamp lighting device of this invention BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a conceptual side view showing an automobile headlamp as an embodiment for carrying out the lighting device of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Translucent ceramics discharge container, 1a ... Enveloping part, 1b ... Small diameter cylindrical part, 2 ... Current introduction conductor, 3 ... Electrode, 4 ... Reduced diameter part, B ... Base, g ... Gap, IT ... Arc tube, L1 , L2 ... Lead wire, MHL ... Metal halide lamp for automotive headlamp, OT ... Outer tube, t1 ... Base terminal, T ... Insulating tube

Claims (5)

A translucent ceramic discharge vessel comprising a surrounding portion and a small diameter tubular portion having a length connected to the surrounding portion of 10 mm or less for a rated lamp power of 800 W or less and 7 mm or less for a rating of 100 W or less;
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;
A high-pressure discharge lamp comprising:   The high-pressure discharge lamp according to claim 1, wherein the small-diameter cylindrical portion has a length of 8.5 mm or less with respect to a rated lamp power of 800 W or less and 5.5 mm or less with respect to 100 W or less.   3. The high-pressure discharge lamp according to claim 1, wherein the small-diameter cylindrical portion has substantially no capillary formed therein. 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:

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