JP2010218988A - High-pressure discharge lamp, and lighting apparatus - Google Patents

Abstract

An arc discharge starting from an undesired position of an electrode component is prevented while reducing erosion of a ceramic hermetic container.
A high-pressure discharge lamp includes a translucent ceramic hermetic container 1, a sealing part 3a, and a halogen-resistant part 3b connected to the tip of the sealing part 3a. A pair of current introduction conductors 3 inserted into the inside of the cylindrical portion 1b, an electrode shaft portion, and a large diameter portion 2b are provided. The tip of the translucent ceramic hermetic container 1 faces the surrounding portion 1a, the large-diameter portion 2b extends from the vicinity of the tip of the electrode shaft portion to the halogen-resistant portion 3b, and the tip of the electrode shaft portion is large. It has a pair of electrodes 2 and 2 forming a protruding portion protruding in the tube axis direction from the diameter portion 2b.
[Selection] Figure 2

Description

  The present invention relates to a high-pressure discharge lamp and an illumination device including the same.

  Compared to metal halide lamps using quartz arc tubes, the metal halide lamps using ceramic arc tubes increase the tube wall load of the arc tube and achieve high efficiency and high color rendering. However, if the tip side of the electrode coil is flush with the tip of the shaft, the rate at which the lamp flickers due to the movement of the discharge bright spot on the electrode coil increases. In order to solve this problem, it is known that the shaft portion of the electrode protrudes from the electrode coil by a predetermined distance (see Patent Document 1).

JP 2000-340172 A

  The high-pressure discharge lamp has a ceramic airtight container, and the airtight container has an enclosing portion that surrounds the discharge space, and a pair of small-diameter cylindrical portions that are referred to as capillaries that extend from the enclosing portion. Yes. The inside of the small diameter cylindrical portion is filled with a metal halide. The metal halide staying in the portion near the surrounding portion inside the small-diameter cylindrical portion liquefies during lighting and reacts with the inner surface of the ceramic hermetic container, thereby eroding the ceramic hermetic container.

  The present inventors have found out that erosion of the ceramic hermetic vessel can be reduced by extending the coil portion wound around the halogen-resistant portion to be sealed in the small-diameter cylindrical portion to the discharge space side. Japanese Patent Application No. 2008-317619 has been filed for a high-pressure discharge lamp in which the coil portion of the portion is extended to the discharge space side.

  However, subsequent research has revealed that when the coil portion of the halogen-resistant portion is extended to the discharge space side, an arc spot may be formed at the end of the coil portion. In such a situation, a crack may occur in the hermetic container due to heat shock, and eventually the hermetic container may burst.

  The present invention has been made in view of the above problems, and ensures the lamp life by preventing the occurrence of arc discharge starting from an undesired position of the electrode component while reducing the erosion of the ceramic hermetic container. An object of the present invention is to provide a high-pressure discharge lamp that can be used and a lighting device using the same.

A high-pressure discharge lamp according to claim 1 is a translucent ceramic hermetic container comprising an enclosing portion that surrounds a discharge space and a pair of small-diameter cylindrical portions that communicate with the enclosing portion and extend from both ends thereof; A pair of current introduction conductors having a halogen-resistant portion connected to the tip of the sealing portion and inserted into the small-diameter cylindrical portion of the translucent ceramic hermetic container; an electrode shaft portion and a large-diameter portion; The shaft is connected at the base end to the tip of the halogen-resistant portion of the current introduction conductor, and the tip faces the enclosure of the translucent ceramic hermetic container. The large-diameter portion is halogen-resistant from the vicinity of the tip of the electrode shaft. A pair of electrodes that are disposed over the part and that form a protruding portion in which the tip of the electrode shaft portion protrudes from the large diameter portion in the tube axis direction;
An ionizing medium containing a rare gas and a metal halide and enclosed in a light-transmitting ceramic airtight container; and sealing between the sealing portion of the current introduction conductor and the small-diameter cylindrical portion to seal the light-transmitting ceramic airtight And a sealing portion that seals the container.

  According to a second aspect of the present invention, in the high-pressure discharge lamp according to the first aspect, an auxiliary electrode is wound around the outer surface of at least one side of the pair of small diameter cylindrical portions.

  Claim 3 is the high-pressure discharge lamp according to claim 1 or 2, wherein the rare gas is mainly xenon of 1 to 5 atm in terms of 25 ° C, and the metal halide is at least one of thulium (Tm) and holmium (Ho). It is characterized in that it is enclosed in a light-transmitting ceramic hermetic container without containing mercury.

  A lighting device according to claim 4 comprises: a lighting device main body; a high-pressure discharge lamp according to any one of claims 1 to 3 disposed in the lighting device main body; and a lighting circuit for lighting the high-pressure discharge lamp. It is characterized by being.

  The translucent ceramic hermetic container means that the hermetic container is mainly composed of translucent ceramics, and means that visible light in a desired wavelength region generated by discharge can be led out. In the translucent ceramic hermetic container, the coldest part temperature can be set high, the lamp voltage can be increased, and the luminous efficiency can be improved. As the translucent ceramic, translucent alumina, yttrium-aluminum-garnet (YAG), yttrium oxide (YOX), and polycrystalline non-oxide such as aluminum nitride (AlN) or single crystal Crystal ceramics or the like can be used. If necessary, it is allowed to form a halogen-resistant or metal-resistant transparent coating on the inner surface of the hermetic container or to modify the inner surface of the translucent hermetic container.

  Further, the translucent ceramic hermetic container has a discharge space therein. And in order to surround discharge space, the surrounding part is provided. The surrounding portion has an appropriate shape such as a spherical shape, an elliptical spherical shape, or a substantially cylindrical shape.

  In addition, a pair of small-diameter cylindrical portions that communicate with the surrounding portion and extend from both ends of the surrounding portion in the tube axis direction are provided. The pair of small diameter cylindrical portions seal the translucent ceramic hermetic container, and the electrode shaft portion is inserted here, and the current supplied from the lighting circuit via the current introduction conductor is hermetically introduced to the electrode. It is a means to contribute to.

  As a sealing means of the translucent ceramic hermetic container, for example, a frit seal in which frit glass is poured between the translucent ceramic and the introduction conductor and sealed, metal sealing using a metal instead of the frit glass and translucency are used. Various sealing means such as a means for directly or indirectly sealing the current-introducing conductor by melting the opening to be sealed of the porous ceramic hermetic container can be selectively adopted as desired. In addition, in order to maintain the lowest temperature of the discharge space at a desired relatively high temperature while maintaining the sealing portion at a required relatively low temperature, the length of the small-diameter cylindrical portion communicating with the surrounding portion is set to a required value. It can also be set to a relatively large value.

  The current introduction conductor is a conductor that functions to apply a voltage to an electrode, which will be described later, to supply a current to the electrode, and to seal the translucent ceramic hermetic container in cooperation with the small-diameter cylindrical portion. For this purpose, the tip side portion inserted into the inside of the small-diameter cylindrical portion of the translucent ceramic hermetic container is connected to the electrode, and the proximal end side is exposed to the outside of the translucent ceramic hermetic container. In addition, in the above, being exposed to the outside of the translucent ceramic hermetic container may be projected to the outside from the translucent ceramic hermetic container, or may not be projected, but power can be supplied from the outside. It only needs to face the outside. The current introduction conductor is composed of a serially connected body of a sealing part and a halogen-resistant part. The sealing portion is a portion that seals the translucent ceramic hermetic container by directly or indirectly sealing with the ceramic of the small-diameter cylindrical portion, and is therefore made of a conductive material having good sealing properties. In contrast, the halogen-resistant portion is made of a material such as tungsten or molybdenum that has low reactivity with the metal halide, and supports the electrode and is interposed between the electrode and the sealing portion. Relieve the thermal expansion difference between them.

  Further, the sealing portion can be formed using a sealing metal or cermet. Examples of the sealing metal include niobium (Nb) and tantalum (Ta), which are conductive metals whose thermal expansion coefficient is similar to that of the translucent ceramic constituting the small-diameter cylindrical portion of the translucent ceramic hermetic container. ), Titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), platinum (Pt), molybdenum (Mo) and tungsten (W) can be used. As a cermet, what consists of a mixed sintered body of the said metal and ceramics is employable.

  When aluminum oxide such as translucent polycrystalline alumina ceramics is used as the material for the translucent ceramic hermetic container, niobium and tantalum have an average coefficient of thermal expansion that is almost the same as that of aluminum oxide. 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 in average thermal expansion coefficient is small. When aluminum nitride is used for the translucent ceramic hermetic container, zirconium may be used for the current introduction conductor.

  Further, the sealing portion can be formed by joining a plurality of material portions. For example, a part may be a metal part selected from the above group, 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 a part of the sealing part of the current introduction conductor, the small-diameter cylindrical part of the translucent ceramic hermetic container at the part of the cermet or the part straddling both the cermet and the sealing metal The sealing portion of the translucent ceramic hermetic container can be formed by sealing with the current introduction conductor. As the cermet, for example, the ceramic of the material component is alumina ceramic, and the metal is one or more kinds of metals selected from the above group, for example, conductive metal such as molybdenum (Mo), tungsten (W) or niobium (Nb). Can be used. Further, the cermet of the portion to be sealed in the translucent ceramic hermetic container of the current introduction conductor includes at least a conductive metal component such as niobium (Nb), molybdenum (Mo) and tungsten, and ceramics such as alumina, YAG and yttria. The content ratio of the metal component is allowed to be 5 to 60% by mass.

  The pair of electrodes constitutes a high-pressure discharge lamp of a type that generates an electrode-shaped discharge that is sealed in a light-transmitting ceramic hermetic container and disposed so as to face the discharge space. In the present invention, the electrode includes an electrode shaft portion and a large diameter portion. The electrode shaft portion is elongated and inserted into the inside of the small-diameter cylindrical portion, the proximal end is connected to the distal end of a current introduction conductor described later, and the distal end is desired in the surrounding portion. The large-diameter portion is disposed on the tip side of the electrode shaft portion at a position where the tip portion of the electrode shaft portion constitutes a protrusion having a predetermined length shown below. That is, the tip of the electrode shaft portion protrudes from the large diameter portion to the discharge space side by a predetermined dimension to form a protruding portion. The predetermined dimension is a position in which the length from the tip of the protruding portion to the large diameter portion is 0.3 to 1.5 mm in the tube axis direction. On the other hand, if the length of the protruding portion is less than 0.3 mm, the discharge arc tends to become unstable.

 In particular, in the configuration of the present invention that is mercury-free and contains at least one halide of thulium and holmium, the discharge arc is stable and practical if the length of the protruding portion of the electrode shaft portion is 0.3 mm or more. A high-pressure discharge lamp is obtained. However, if the length of the protruding portion exceeds 1.5 mm, the design of a long-life high-pressure discharge lamp that secures a desired inter-electrode distance inside the surrounding portion and has high luminous efficiency and luminous flux maintenance rate is possible. Since it becomes difficult, in the present invention, the length of the protruding portion is preferably in the range of 0.3 to 1.5 mm. In addition, it is 0.6-1.0 mm suitably.

  Since the diameter of the large diameter portion tends to affect the flickering of the discharge arc, the ratio C to the inner diameter of the small diameter cylindrical portion is preferably a value satisfying 0.70 ≦ C ≦ 0.95. When the diameter ratio C of the large diameter portion is less than 0.7, flickering of the discharge arc is likely to occur. Moreover, when it exceeds 0.95 times, it becomes difficult to insert an electrode into a small diameter cylinder part from the outside. The range preferably satisfies 0.85 ≦ C ≦ 0.95.

  The large diameter portion may be an electrode coil formed by winding a heat-resistant metal wire around the electrode shaft portion. The whole may be a lump with a solid interior of the heat-resistant metal. When the large-diameter portion is in a lump shape, it may be integrally formed with the electrode shaft portion, or the large-diameter portion formed separately from the electrode shaft portion may be fixed to the electrode shaft portion by welding or the like. The large-diameter portion is disposed from the vicinity of the tip of the electrode shaft portion to the halogen-resistant portion of the current introduction conductor. The large diameter portion may be formed integrally with the halogen resistant portion.

  Moreover, as a constituent material of the electrode, it is preferable to use a heat-resistant and conductive metal. For example, doped tungsten containing pure tungsten (W), a dopant (for example, one or more selected from the group of scandium (Sc), aluminum (Al), potassium (K) and silicon (Si)), Triated tungsten containing rhodium oxide, rhenium (Re) or tungsten-rhenium (W-Re) alloy.

  The halogen-resistant portion of the current introduction conductor is preferably a subcoil made of a thin wire of heat-resistant metal wound around the electrode shaft portion and the outer peripheral surface thereof. As the heat-resistant metal forming the subcoil, tungsten, molybdenum, or the like can be used. The subcoil may be integral with the electrode coil. The electrode and the current introduction conductor are connected in series in advance before being incorporated in the translucent ceramic hermetic container, thereby constituting an electrode mount.

In the case of a mercury-free lamp, the distance between the electrodes formed between the tips of the pair of electrodes is preferably set relatively large as follows for the purpose of obtaining a practical lamp voltage. This is because a high-pressure discharge lamp that encapsulates a metal halide having a ionization energy of 8 eV or more and a melting point of 500 ° C. or less, for example, ZnI _2, as a metal halide for forming a lamp voltage is mercury-free. This is because the lamp voltage does not increase as much as the case. That is, for example, the distance between electrodes is 16 to 38 mm for the lamp power 100 W class, and 9 to 22 mm for the 35 W class. Further, the metal halide for forming the lamp voltage such as ZnI ₂ is sealed in an amount of 0.3 to 1.6 mg / cc with respect to the inner volume of the hermetic vessel, and the lamp power is 100 W class and the same 14 to 32 mm and 35 W class. Similarly, if it is set to 7 to 18 mm, a higher desired lamp voltage can be obtained. In addition to the distance between these electrodes, if the maximum inner diameter of the translucent ceramic hermetic vessel is set to 4 to 7 mm for the lamp power 100 W class and 3 to 5 mm for the 35 W class, the temperature of the coldest part of the arc tube The light emission efficiency can be kept high by maintaining high.

  The sealing part seals between the sealing part of the current introduction conductor and the small diameter cylinder part

Thus, the translucent ceramic hermetic container is sealed, but in the present invention, the above sealing may be performed using frit glass, or the sealing portion of the current introduction conductor and the small diameter cylinder The part may be fused directly.

  According to the present invention, the tip of the electrode shaft portion has a protruding portion that protrudes in the tube axis direction from the large diameter portion, and the large diameter portion is disposed from the vicinity of the tip of the electrode shaft portion to the halogen-resistant portion. In addition, since the arc discharge starting from the protruding part is stably generated while reducing the erosion of the ceramic hermetic container, the ceramic hermetic container can be prevented from rupture due to the arc discharge starting from an undesired position of the electrode parts. Further, it is possible to provide a high-pressure discharge lamp capable of ensuring the lamp life and a lighting device including the same.

The front view which shows the 1st form for implementing the high pressure discharge lamp of this invention. Similarly, an enlarged cross section of the arc tube. Similarly the enlarged front view of an electrode mount. Sectional drawing which shows the ceiling embedded downlight as one form for implementing the illuminating device of this invention.

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

  1 to 3 show an embodiment for implementing the high-pressure discharge lamp of the present invention. FIG. 1 is a front view of the entire high-pressure discharge lamp, FIG. 2 is an enlarged sectional view of the arc tube, and FIG. It is an enlarged front view.

  The high-pressure discharge lamp of the present embodiment has a rated lamp power of 100 W type, a translucent ceramic hermetic container 1, a pair of electrodes 2, 2, a pair of current introduction conductors 3, 3, a pair of sealing portions 4, 4, and electrodes. A mount subcoil SC and an ionization medium are provided, and these components constitute the arc tube IT. In addition to the arc tube IT, an outer tube OT, a proximity conductor TW as a starting auxiliary means, and an ultraviolet radiation discharge tube UVE are provided. In the figure, SG is a protective glass tube, SF is an arc tube support member, G is a getter, and B is a base.

  The translucent ceramic hermetic container 1 is made of translucent ceramics, for example, translucent polycrystalline alumina ceramics. And it is provided with the surrounding part 1a and a pair of small diameter cylindrical parts 1b and 1b, and has comprised the integrally molded structure. The surrounding portion 1a has a bowl shape, and includes an intermediate cylindrical portion and a pair of hemispherical portions continuous to both ends thereof. And the surrounding part 1a surrounds the discharge space 1c formed in the inside. The small-diameter cylindrical portion 1b has a long and narrow pipe shape, and has a tip communicating with the central portion of the hemispherical portion of the surrounding portion 1a and extending outward along the tube axis.

  As shown in FIGS. 2 and 3, the electrode 2 includes an electrode shaft portion 2a and a large diameter portion 2b. And it consists of a rod-like body of doped tungsten. The electrode shaft portion 2a is inserted into the elongated and small-diameter cylindrical portion 1b, the tip thereof faces the inside of the surrounding portion 1a of the translucent ceramic hermetic container 1, and the base end is butt welded to the tip of the current introduction conductor 3. Has been. The large-diameter portion 2b is disposed over a halogen-resistant portion 2b described later from a position slightly retracted from the tip of the electrode shaft portion 2a on the tip side of the electrode shaft portion 2a. For this reason, the protrusion part 2a1 of predetermined length A (mm) is formed from the front-end | tip of the large diameter part 2b. In this embodiment, the large diameter portion 2b is formed by an electrode coil formed by winding a doped tungsten wire around the electrode shaft portion 2a. The predetermined length A (mm) is set in a range satisfying 0.3 ≦ A ≦ 1.5.

  When the high-pressure discharge lamp has a rated lamp power of 50 W or less, when the diameter of the large diameter portion 2b is d3 and the inner diameter of the small diameter cylindrical portion 1b is d1, d3 / d1 is the ratio C, and C is 0.7 ≦ C It is set within a range satisfying ≦ 0.95.

  As shown in FIGS. 2 and 3, the current introduction conductor 3 includes a sealing portion 3 a and a halogen-resistant portion 3 b connected in series with each other, and the current introduction conductor 3 includes a small-diameter cylindrical portion 1 b of the translucent ceramic hermetic container 1. Inserted inside. The sealing portion 3a is composed of a two-obed rod-like body and is sealed with the small-diameter cylindrical portion 1b to form the sealing portion 4 of the translucent ceramic hermetic container 1, and the base end thereof is translucent ceramic. It is exposed to the outside of the airtight container 1. The halogen-resistant portion 3b is made of a molybdenum rod-like body, and its base end is butt welded to the tip of the sealing portion 3a. Further, the base end of the electrode shaft portion 2a is welded to the tip end portion.

  As shown in FIGS. 2 and 3, the subcoil 3c is arranged by winding a thin thin wire of doped tungsten around the outer peripheral surface of the electrode shaft portion 2a and the halogen-resistant portion 2b of the current introduction conductor in the small diameter cylindrical portion 1b. Has been. Therefore, a slight gap is formed between the outer peripheral surface of the subcoil 3c and the inner surface of the small diameter cylindrical portion 1b. When the inner diameter of the small diameter cylindrical portion is d1 and the outer diameter of the subcoil 3c is d2, the ratio d2 / d1 is the ratio B of the outer diameter of the subcoil 3c to the inner diameter of the small diameter cylindrical portion 1b of the subcoil 3c. In the present embodiment, the value of B is set within a range that satisfies 0.65 ≦ B ≦ 0.95.

  In this embodiment, both the electrode coil of the large diameter portion 2b and the subcoil 3c of the halogen resistant portion 2b are doped tungsten wires, and both are integrally wound. You may wind separately with respect to the halogenous part 2b, respectively.

  In this embodiment, the sealing portion 4 is made of a frit glass, that is, a melted and solidified body of a ceramic compound, and enters the small-diameter cylindrical portion 1b in a molten state, and is a current introduction conductor located in the small-diameter cylindrical portion 1b. 3 is sealed so that the gap between the sealing portion 3a and the inner surface of the small-diameter cylindrical portion 1b is hermetically sealed and the surface of the sealing portion 3a is not exposed in the translucent ceramics hermetic container 1. ing.

  The present invention can be applied to a mercury-enclosed lamp, but can also be applied to a mercury-free high-pressure discharge lamp that has little influence on the environmental load. This embodiment will be described as an application example of a mercury-free high-pressure discharge lamp.

  The ionization medium is enclosed in the translucent ceramic hermetic container 1 and contains a metal halide and a rare gas, but does not contain mercury. In the present invention, the metal halide contains at least one of thulium (Tm) and holmium (Ho), the rare gas is mainly xenon, and the enclosed pressure is 1 to 5 atm in terms of 25 ° C. Preferably, a metal halide having an ionization energy of 8 eV or more and a melting point of 500 ° C. or less is enclosed for forming a lamp voltage.

  Thulium (Tm) emits a number of emission line spectra near the peak wavelength of the luminous characteristic curve at the time of discharge, and its emission peak coincides with the peak of the luminous efficiency curve, so it is extremely effective in improving luminous efficiency. Light emitting metal. However, these metal halides are mainly metal halides that contribute to light emission, but also have an action of increasing the lamp voltage in a mercury-free manner. For this reason, it is possible to reduce the amount of metal halide mainly for forming the lamp voltage. As a result, it is possible to avoid an adverse effect (increase in color deviation) that occurs when a relatively excessive amount of metal halide for forming a lamp voltage is enclosed. Holmium also has properties similar to those described above for thulium.

  In general, the metal that mainly contributes to the light emission is a metal that clearly contributes to the light emission as the high-pressure discharge lamp, and it does not matter whether the lamp voltage is formed or not. Therefore, the metal that contributes to light emission is also a light-emitting metal excluding the metal halide for forming a lamp voltage, which will be described later. However, thulium and holmium correspond to metals that contribute to light emission because of the large amount of light emission in the visible region as described above, but in addition to this, they also have a lamp voltage forming action.

  In addition, it contains at least one halide of thulium (Tm) and holmium (Ho) as the main component of a metal halide that mainly contributes to light emission, and xenon-based rare gas is sealed at 1 to 3 atm in terms of 25 ° C. In a preferred embodiment of the present invention, the chromaticity deviation duv. This is good because the change width is extremely small. In addition, in this aspect, since the emission amount in the blue region is significantly smaller than when the sealed pressure mainly composed of xenon is higher than the above, the emission efficiency is increased, and the emission in the blue region is reduced as compared with the case where it is lower than the above. Therefore, the chromaticity deviation does not deteriorate beyond the practical level.

Furthermore, when encapsulating thulium (Tm) and holmium (Ho) halides mainly as metal halides that contribute to light emission, the total of them excludes metal halides for forming lamp voltage, which will be described later. It is preferable that it is 35 mass% or more with respect to the whole metal halide which contributes to. If it is this range, thulium (Tm) and holmium (Ho) will exhibit the effect | action which raises a lamp voltage fully to a practical range, and high luminous efficiency will be obtained. For this reason, even if the amount of the metal halide for forming the lamp voltage such as ZnI ₂ is reduced to, for example, 1/5 of the conventional case, a lamp voltage equivalent to that before the amount of reduction can be obtained. it can. Since the color deviation increases as the amount of the metal halide for forming the lamp voltage increases, the color deviation is remarkably improved by decreasing the amount of the metal halide for forming the lamp voltage.

  Furthermore, when the total of thulium (Tm) and holmium (Ho) halides is 50% by mass or more based on the total of metal halides mainly contributing to light emission, higher lamp voltage and higher luminous efficiency can be obtained. Since it can obtain, it is much more suitable. However, when the encapsulation ratio exceeds 80% by mass, the ratio at which metal halides other than thulium (Tm) and holmium (Ho) can be encapsulated is correspondingly reduced. As a result, desired white light emission cannot be obtained, which is not preferable for the purpose of obtaining white light emission. Further, when the enclosure ratio of thulium (Tm) and holmium (Ho) halide is in the range of 50 to 70% by mass, particularly high luminous efficiency is obtained.

  If desired, thallium (Tl) can be added to the ionization medium. When a thallium (Tl) halide or metal thallium is enclosed, the green light emission of thallium (Tl) is added to at least one kind of light emission of thulium (Tm) and holmium (Ho), so that the luminous efficiency of the high-pressure discharge lamp is high. Become.

  In addition to obtaining white light emission, other metal halides other than those described above can be selectively added, for example, for the purpose of adjusting the chromaticity of light emission or increasing the light emission efficiency. Hereinafter, main examples in the case of adding other metal halides will be described.

  When encapsulating a halide of a metal that mainly emits an alkali metal such as sodium (Na), the amount of the encapsulated metal is controlled to 30% by mass or less based on the total amount of the halide of the mainly emitting metal. The voltage can be kept high. Further, when the content is 25% by mass or less, in the present invention, the emission of alkali metal is weakened, and on the contrary, the emission ratio of the rare earth metal is increased, so that the average color rendering index Ra is increased.

  The rare earth metal halide is composed of at least one of thulium (Tm) and holmium (Ho), and one or more kinds of halides of praseodymium (Pr), cerium (Ce), dysprosium (Dy) and samarium (Sm). It can be encapsulated as a minor component. The rare earth metal is useful as a luminescent metal next to thulium halide and holmium halide, and is allowed to be encapsulated at an encapsulation ratio as an accessory component. Note that any of the rare earth metals has an innumerable emission line spectrum near the peak wavelength of the visibility characteristic curve, and thus can contribute to an improvement in luminous efficiency.

  Indium (In) halide is allowed to be selectively encapsulated as a subcomponent for the purpose of obtaining a desired color rendering property and / or color temperature.

  As the halogen forming each of the above halides, iodine is suitable because it has moderate reactivity, but it may be either bromine or chlorine as desired, and any of iodine, bromine and chlorine is desirable. Two or more of these may be used.

  Next, the metal halide for forming the lamp voltage will be described. A metal halide for forming a lamp voltage can be sealed inside the translucent ceramic hermetic vessel 1 as desired. The metal halide for forming the lamp voltage often includes a metal halide having an ionization energy of 8 eV or more and a melting point of 500 ° C. or less.

  In the present invention, if a mode in which at least one kind of thulium halide and holmium halide is sealed in a predetermined ratio and xenon main body is sealed in 3 to 5 atmospheres, a desired lamp voltage is formed. It is not necessary to enclose the halide. However, in the present invention, the amount of at least one of thulium halide and holmium halide to be encapsulated is not particularly limited, and xenon is mainly encapsulated within a range of 1 to 5 atm in terms of 25 ° C. If necessary to form a potential gradient of 7 V / mm or more between the electrodes, it is permissible to enclose a required amount of a metal halide for forming a lamp voltage. In this case, it is preferable to enclose within a range of 0.3 to 1.6 mg / cc with respect to the inner volume of the translucent ceramic hermetic container 1.

  Further, the metal halide for forming the lamp voltage has a higher vapor pressure than the above-mentioned halide enclosed in the translucent ceramic hermetic vessel 1 in the present invention, and mainly determines the lamp voltage in the high-pressure discharge lamp. There is an effect. Note that “high vapor pressure” means that the vapor pressure during lighting is high, but it is not necessary to be too high like mercury, and preferably the pressure in the translucent ceramic hermetic container 1 during lighting is It is about 5 atmospheres or less. Therefore, it is not limited to a specific metal halide as long as the above conditions are satisfied.

  The lamp voltage forming halide is mainly composed of a metal halide that forms a lamp voltage. For example, magnesium (Mg), iron (Fe), cobalt (Co), chromium (Cr), zinc (Zn), From nickel (Ni), manganese (Mn), aluminum (Al), antimony (Sb), beryllium (Be), rhenium (Re), gallium (Ga), titanium (Ti), zirconium (Zr) and hafnium (Hf) One or a plurality of types of metal halides selected from the group can be used as a main component. Most of them have a vapor pressure lower than that of mercury, and the adjustment range of the lamp voltage is narrower than that of mercury.

  Next, the rare gas will be described. The reason for enclosing 1 to 5 atm of xenon (Xe) as a rare gas in terms of 25 ° C. is to reduce the starting voltage and obtain compatibility with high pressure discharge lamps, lighting fixtures and wiring for general lighting containing mercury. This is because it is a necessary premise. However, it is preferably 1 to 3 atm.

  Xenon-based means that the volume of xenon may be 80% or more. Examples of rare gases that can be mixed with xenon include argon (Ar), krypton (Kr), and neon (Ne).

  The outer tube OB accommodates members such as the arc tube IT, the proximity conductor TW as a starting auxiliary means, the ultraviolet radiation discharge tube UVE, the protective glass tube SG, the arc tube support member SF, and the getter G in a predetermined position. The inside is in a vacuum. Further, the outer tube OT is provided with a flare stem 5 sealed at a neck portion located at the lower portion in the drawing. The flare stem 5 is provided with a pair of internal lead-in wires 6a and 6b protruding in an airtight manner into the outer tube OT.

  Further, the outer tube OT has the arc tube IT arranged at a substantially central portion of the outer tube OT along the central axis of the outer tube OT, and the upper current introduction conductor 3 is welded to a connection piece 10 to be described later and supported. At the same time, it is connected to the internal lead-in wire 6a via the arc tube support member SF. The current introduction conductor 3 below the arc tube IT is welded to and supported by the connection conductor 7 and is connected to the internal introduction line 6b via the connection conductor 7.

  The protective glass tube SG is made of a quartz glass cylinder, and surrounds the arc tube IT in a separated state, thereby suppressing the scattering of fragments when the arc tube IT is ruptured. And it is supported by the arc tube support member SF as will be described later.

  The arc tube support member SF includes a support frame 8, a pair of support plates 9 and 9, and a connection piece 10. The support frame 8 is formed by bending a stainless steel rod into a vertically long U-shape and is connected to the internal lead-in wire 6a. The pair of support plates 9, 9 are formed of a stainless steel plate in a substantially disk shape and are fixed to the support frame 8. Further, a through hole is formed in the central portion of the pair of support plates 9, and the arc tube is formed by inserting the pair of small diameter cylindrical portions 1 b and 1 b of the translucent ceramic hermetic container 1 into the through hole. IT is fixed at the tube axis position of the outer tube OT, and the arc tube IT is supported in the tube axis direction. The connection piece 10 is welded to the upper part of the support frame 8, and is connected to the upper current introduction conductor 3 in the figure of the arc tube IT. The pair of support plates 9 and 9 are fitted to the upper and lower end surfaces of the protective glass tube SG, sandwich the protective glass tube SG therebetween, and are fixed to the arc tube support member SF. Therefore, the protective glass tube SG is supported by the arc tube support member SF via the pair of support plates 9 and 9. The getter G is a performance getter supported at the upper part in the figure of the arc tube support member SF.

  The base B is a screw-type base and is attached to the lower part of the outer tube OT in FIG. 1 and connected to the pair of internal lead-in wires 6a and 6b.

  In the present invention, when the enclosed pressure of the xenon of the ionization medium is relatively low within an allowable range, the starting voltage is relatively lowered. Therefore, even if only the proximity conductor is provided, the starting high voltage is 5 kV or less. It can be started by applying. On the other hand, when the noble gas filling pressure is relatively high within the allowable range, the starting voltage is relatively high. Therefore, if both the proximity conductor and the ultraviolet radiation means are used in combination, the starting voltage is 5 kV or less. It can be started by applying a voltage. In addition to the proximity conductor and the ultraviolet radiation means, it is allowed to use other start assisting means together if desired.

  The starting assisting means is disposed in the outer tube OT, and when a high voltage for starting is applied between the pair of electrodes 2 and 2 disposed in the translucent ceramic hermetic container 1, It is means for assisting starting so that discharge of the ionized medium starts. In this embodiment, the starting auxiliary means includes the proximity conductor TW and the ultraviolet radiation means UVE. However, in the present invention, it is allowed to employ at least one of the two means. Further, if desired, other known starting aids such as a starter can be used in combination.

  One end of the proximity conductor TW is welded to the upper current introduction conductor 3 in FIG. 1 of the arc tube IT. The intermediate portion is wound around the translucent ceramic hermetic container 1 in the vicinity of the boundary between the upper small-diameter cylindrical portion 1b and the surrounding portion 1a to form the ring portion r1, and the tube is provided close to the outer periphery of the surrounding portion 1a. It extends downward along the axial direction. Further, the ring portion r2 is formed by being wound around the translucent ceramic hermetic container 1 in the vicinity of the boundary portion between the lower diameter cylindrical portion 1b and the surrounding portion 1a.

  Thus, the proximity conductor TW is disposed so as to form a large potential gradient at a short distance between the tip and the other electrode 2 facing the tip. By providing the proximity conductor TW, the high-pressure discharge lamp is easily broken down when a high voltage for starting is applied, and the starting thereof is promoted. When the high pressure discharge lamp is started, glow discharge is generated in the arc tube, and further transitioned to arc discharge, the proximity conductor TW is short-circuited by the arc tube IT, so that the lighting of the high pressure discharge lamp is not hindered. Absent.

  The ultraviolet radiation discharge tube UV is a UV enhancer, and the tip of one conductor l1 is sealed in a small and ultraviolet-permeable airtight container to form an internal electrode. One conductor l1 is welded to the current introduction conductor 3 below the arc tube IT in FIG. The other conductor 12 holding the ultraviolet permeable airtight container is welded to a support frame 8 of the arc tube support member SF described later to form an external electrode. Therefore, the ultraviolet radiation discharge tube UV is connected in parallel to the arc tube IT. A UV-radiating rare gas or the like is sealed in the UV-permeable airtight container.

  Thus, when a high starting voltage is applied between the pair of electrodes 2 and 2 prior to the start of the high pressure discharge lamp, the discharge starts first, and the generated ultraviolet rays are irradiated to the vicinity of the electrode below the arc tube IT. To do. As a result, the ionization medium in the arc tube IT is excited and easily started.

  Thus, the ultraviolet radiation means UVE operates when the high pressure discharge lamp is started to generate ultraviolet light, and irradiates it in the vicinity of one electrode of the arc tube IT. As a result, electrons are emitted from the electrodes and the like, and become initial electrons, which accelerates the start of the high-pressure discharge lamp. When the high pressure discharge lamp is started, the ultraviolet radiation means is short-circuited by the discharge arc generated in the arc tube IT, so that it does not hinder lighting.

  The starter is configured with a switching means such as a glow starter, a bimetal switch or a non-linear capacitor, and is arranged in the outer tube to perform a rapid switching operation when the power is turned on. The generated high voltage for starting is applied between the electrodes 2 and 2 of the arc tube IT to facilitate starting of the high pressure discharge lamp.

  When the high-pressure discharge lamp of the present invention is provided with a starting auxiliary means, even if the starting high voltage is 5 kV or less, this can be applied to start the high-pressure discharge lamp. Of course, the high-pressure discharge lamp of the present invention can be lit by applying a high starting voltage exceeding 5 kV. As a starting high voltage applying means, for example, a high voltage pulse generator called an igniter is combined with a high pressure discharge lamp, and a high voltage pulse generated from the high voltage pulse lamp is applied and a high voltage discharge lamp is turned on using a ballast. In so doing, any of the modes in which a so-called kick voltage generated therefrom is applied to the arc tube from the outside of the high-pressure discharge lamp may be used.

According to the high-pressure discharge lamp 11 of the present embodiment, the large-diameter portion 2b is disposed together with the subcoil 3c from the vicinity of the tip of the electrode shaft portion 2a to the halogen-resistant portion 3b, so that the erosion of the ceramic hermetic container is reduced. There is no end portion of the subcoil extending from the halogen-resistant portion 3b to the discharge space 1c side, and no arc spot is formed in this portion. Therefore, the arc discharge is generated starting from the protruding portion 2a1 that protrudes from the large diameter portion in the tube axis direction while reducing the erosion of the ceramic hermetic vessel 11, and thus undesired positions of the electrode parts are formed. It is possible to prevent the occurrence of cracks in the hermetic container 11 due to heat shock caused by the occurrence of arc discharge as a starting point.
Next, examples will be described.

  Example 1 is a metal halide lamp shown in FIG.

  Translucent ceramic hermetic container: Polycrystalline alumina ceramics integral molding, internal volume 0.6cc, small diameter cylindrical part inner diameter 1.0mm

  Pair of electrodes: distance between electrodes 6.0 mm, length of protrusion A = 1.0 mm,

  Electrode coil and sub-coil: Outer diameter (ratio of inner diameter of small cylindrical part) B = 0.95

Ionization medium: TmI ₃ -NaI = 6.0 mg (content ratio of TmI ₃ 75%), ZnI ₂ = 1.2 mg, Xe4 atm High voltage for starting: 4.0 kV
Base: Base for commercial general lighting HID

  Electrical characteristics: Lamp voltage 64V, lamp power 100W, ballast uses dedicated ballast

  Luminescent characteristics: luminous efficiency 90 lm / W, discharge arc instability was zero.

  FIG. 4 is a cross-sectional view showing a ceiling-embedded downlight as an embodiment for implementing the lighting device of the present invention.

  In the figure, 11 is a high-pressure discharge lamp, and 12 is a lighting fixture body.

  The high-pressure discharge lamp 11 is the same as that in one embodiment for implementing the high-pressure discharge lamp of the present invention shown in FIG.

  The luminaire main body 12 constitutes a ceiling-embedded downlight, and includes a base 12a and a reflector 12b. Since the base 12a is embedded in the ceiling, the base 12a has a ceiling contact edge 12a1 at the lower end. The reflection plate 12b is supported by the base body 12a and surrounds the light emission center of the high-pressure discharge lamp 11 so that it is located at substantially the focal point.

  A high-pressure discharge lamp lighting device (not shown) for lighting the high-pressure discharge lamp 11 is disposed on the lighting fixture body 12 or at a position adjacent to the lighting fixture body 12 or a remote position. It can be set separately.

DESCRIPTION OF SYMBOLS 1 ... Translucent ceramic airtight container, 1a ... Enclosing part, 1b ... Small diameter cylinder part, 1c ... Discharge space, 2 ... Electrode, 2a ... Electrode axial part, 2a1 ... Projection part, 2b ... Large diameter part, 3 ... Current introduction Conductor, 3a ... Sealing part, 3b ... Halogen resistant part, 3b ... Halogen resistant part, 4 ... Sealing part, IT ... Arc tube, OT ... Outer tube, TW ... Proximity conductor.

Claims (4)

A translucent ceramic hermetic container including an enclosing portion surrounding the discharge space and a pair of small-diameter cylindrical portions communicating with the enclosing portion and extending from both ends thereof;
A pair of current introduction conductors having a sealing portion and a halogen-resistant portion connected to the tip of the sealing portion, and being inserted into the small-diameter cylindrical portion of the translucent ceramic hermetic container;
An electrode shaft portion and a large-diameter portion are provided. The electrode shaft portion has a proximal end connected to the distal end of the halogen-resistant portion of the current introduction conductor, and the distal end faces the enclosure portion of the translucent ceramic hermetic container. And a pair of electrodes that are arranged from the vicinity of the tip of the electrode shaft portion to the halogen-resistant portion, and the tip of the electrode shaft portion forms a protruding portion that protrudes from the large diameter portion in the tube axis direction;

An ionization medium containing a rare gas and a metal halide and enclosed in a translucent ceramic hermetic container;

A sealing portion that seals the translucent ceramic hermetic container by sealing between the sealing portion of the current introduction conductor and the small-diameter cylindrical portion;
A high-pressure discharge lamp comprising:   2. The high pressure discharge lamp according to claim 1, wherein an auxiliary electrode is wound around an outer surface of at least one side of the pair of small diameter cylindrical portions.   The rare gas is mainly xenon at 25 ° C. converted to 25 ° C., the metal halide contains at least one halide of thulium (Tm) and holmium (Ho), and does not contain mercury. The high-pressure discharge lamp according to claim 1 or 2, wherein the high-pressure discharge lamp is enclosed in an inside. 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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