JP2010140826A - High-pressure discharge lamp, and lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mercury-free high-pressure discharge lamp which has a high lamp voltage and high light emission efficiency practical in using for general illumination even when a sealing pressure of xenon is relatively low, and which has excellent stability of an arc, and to provide a lighting system using the same. <P>SOLUTION: The high-pressure discharge lamp includes: a translucent hermetically-sealed ceramic vessel 1; a pair of current introducing conductors 3 inserted into small-diameter cylinder parts; a pair of electrodes each having an electrode shaft part 2a and a large-diameter part 2b, wherein the electrode shaft part is connected to a tip end of the current introducing conductor and a tip end of the electrode shaft part projects from the large-diameter part and forms a projection part having a length A in a tube axis direction; an electrode mount sub coil SC having a ratio B of an outer diameter with respect to an inner diameter of the small-diameter cylinder part; an ionization medium in which rare gas is mainly xenon at 1-5 atm, contains halide of at least one of Tm and Ho, and which is sealed without containing mercury; and a sealing part 4. The numerical value A, B, and a sum of them are in predetermined ranges respectively. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a mercury-free high-pressure discharge lamp that essentially does not contain mercury, and an illumination device including the same.

  There is known a high-pressure discharge lamp in which a metal halide effective in forming a lamp voltage, such as zinc, which emits less light in the visible region is enclosed in place of mercury and made mercury-free (for example, see Patent Document 1). .)

  Regarding the mercury-free high-pressure discharge lamp, there are a large number of patent documents in addition to the above, and the enclosure pressure of rare gas is widely disclosed up to about 0.1 to 25 atm. In many cases, the appropriate rare gas pressure is stated to be 5 to 7 atmospheres or more. In this case, the starting high voltage applied to start the high-pressure discharge lamp is 8 kV or more, and xenon is started at 10 atmospheres. The high voltage for use will be 15-20 kV.

  However, in mercury-free high-pressure discharge lamps, metal halides that have low visible light emission, such as zinc, and are effective in forming the lamp voltage increase the lamp voltage as the amount of encapsulation increases. On the other hand, there is a problem that the luminous efficiency of the high-pressure discharge lamp is lowered.

In contrast, thulium (Tm) and holmium (Ho) halides, unlike other rare earth metal halides, provide a high lamp voltage increase effect in addition to high luminous efficiency. Therefore, the amount of the metal halide for forming the lamp voltage such as ZnI ₂ can be reduced to suppress the above problem, and as a result, high luminous efficiency can be maintained despite the relatively low xenon encapsulation pressure. (See Patent Document 2).

  In the high pressure discharge lamp of Patent Document 2, the sealed pressure of xenon is 3 to 15 atm, and when it exceeds 5 atm, the starting voltage becomes too high as a high pressure discharge lamp for general illumination. That is, in order to adapt the mercury-free high-pressure discharge lamp to general lighting applications, the E-shaped base is widely used, and thus it is necessary to attach this base. In this case, since the withstand voltage of the E-shaped base is low, it is desirable that the E-type base can be started with a high starting voltage of 5 kV or less. If the starting voltage exceeds 5 kV, compatibility with a high-pressure discharge lamp containing mercury, a lighting fixture using the same, and wiring cannot be obtained. Therefore, it is necessary to employ a dedicated base, which increases the cost of the lighting system.

  On the other hand, metal halide lamps using ceramic arc tubes have higher tube wall load and higher efficiency and higher color rendering than metal halide lamps using quartz arc tubes. When the front end side of the coil is flush with the front end of the shaft portion, 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 3). In this high-pressure discharge lamp, a predetermined amount of mercury, a starting rare gas, and an iodide pellet 13 made of a metal halide are enclosed in an arc tube, and argon is used as the starting rare gas. As the iodide pellets, a mixture of dysprosium iodide, thulium iodide, holmium iodide, thallium iodide, and sodium iodide is used (paragraphs 0018 and 0039).

JP 11-238488 A JP 2008-177160 A JP 2000-340172 A

  As a result of testing conducted by the present inventor using the same light-transmitting hermetic vessel, electrode and ionization medium as a known mercury-free high-pressure discharge lamp of about 10 atm of xenon, the lamp voltage and Luminous efficiency is low and problems are likely to occur in practice. The problem is particularly noticeable at less than 1 atm. However, it has been confirmed that in a mercury-free high-pressure discharge lamp, if the xenon sealing pressure is 1 to 5 atm, the practical minimum level can be maintained by other lamp parameter designs. Further, if the xenon sealing pressure is up to 5 atm, it is possible to start at a high starting voltage of up to 5 kV by using appropriate start assisting means. Furthermore, it has been found that a mercury-free high-pressure discharge lamp using a light-transmitting ceramic hermetic vessel can even be instantly turned on, which is impossible with conventional ceramic metal halide lamps for general lighting.

  As a result of examination, trial production and test by the present inventors, the metal halide of the ionization medium contains at least one halide of thulium (Tm) and holmium (Ho), and the starting gas is 1 to 5 atm in terms of 25 ° C. By adopting a configuration that is main and does not contain mercury, it has become possible to provide a mercury-free high-pressure discharge lamp that has high luminous efficiency and high lamp voltage and is practical for general lighting applications.

  However, it has been found that the stability of the discharge arc may be significantly inferior to the conventional high-pressure discharge lamp containing mercury and the mercury-free high-pressure discharge lamp. Therefore, when the shaft portion of the electrode was protruded from the electrode coil, the mercury-free high-pressure discharge lamp practical for use in the general lighting application described above was used to stabilize the discharge arc within the range described in Patent Document 3. It turned out that a sufficient effect cannot always be obtained.

  Therefore, as a result of further investigation, the present inventor has not only made the shaft portion of the electrode project from the electrode coil but also the electrode mount subcoil in the mercury-free high-pressure discharge lamp practical for the above general lighting application. It was found that the stability of the discharge arc can be obtained when the outer diameter is set to a predetermined ratio with respect to the inner diameter of the small-diameter cylindrical portion, and the present invention has been made.

  The present invention uses a mercury-free high-pressure discharge lamp that has a high lamp voltage and luminous efficiency that are practical in general lighting applications and has excellent arc stability even when the sealed pressure of xenon is relatively low, and the same. An object is to provide a lighting device.

  The high-pressure discharge lamp of the present invention includes a light-transmitting ceramic hermetic container including an enclosure portion surrounding a discharge space and a pair of small-diameter cylinder portions extending from both ends thereof and communicating with the enclosure portion; A pair of current introduction conductors having a refractory portion connected to the tip of the wearable portion and inserted into the small-diameter cylindrical portion of the translucent ceramic hermetic container; and an electrode shaft portion having an electrode shaft portion and a large diameter portion Is connected to the tip of the refractory portion of the current introduction conductor, the tip faces the enclosure of the translucent ceramic hermetic container, and the large diameter portion is disposed near the tip of the electrode shaft portion, A pair of electrodes forming a protruding portion having a length A of 0.3 to 1.5 mm protruding from the large-diameter portion at the tip of the electrode shaft portion and protruding in the tube axis direction; The ratio B of the outer diameter to the inner diameter of the small diameter cylindrical portion is 0.65 ≦ B ≦ 0. 5 and the electrode mount subcoil wound around the outer peripheral surface of the electrode shaft portion and the refractory portion of the current introduction conductor; including a rare gas and a metal halide, and the rare gas is 1 to 5 atm in terms of 25 ° C. An ionization medium mainly composed of xenon, wherein the metal halide contains at least one halide of thulium (Tm) and holmium (Ho), and does not contain mercury, and is enclosed in a light-transmitting ceramic hermetic container; The sealing part which seals the translucent ceramic airtight container by sealing between the sealing part of this and a small diameter cylinder part is characterized by comprising.

  [Translucent ceramic hermetic container] The translucent ceramic hermetic container is composed of translucent ceramics as the main component, and can emit visible light in the desired wavelength range generated by discharge to the outside. It means that. 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. 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 general illumination lamp, it can be any of 0.1 cc or more and the following depending on the rated lamp power. Moreover, if the maximum inner diameter of the translucent airtight container is set to 4 to 7 mm in the lamp power 100 W class and set to 3 to 5 mm in the 35 W class, the temperature of the coldest part is kept high and the luminous efficiency is kept high. It is effective.

  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.

  Further, in the present invention, details will be described later, but the sealing portion of the translucent ceramic hermetic container is disposed at the end portion of the small-diameter cylindrical portion, and the electrode shaft portion extends into the small-diameter cylindrical portion. An electrode mount subcoil is disposed on the outer peripheral surface of the electrode shaft portion. A slight gap called a capillary is formed between the electrode mount subcoil and the inner surface of the small diameter cylindrical portion along the axial direction of the small diameter cylindrical portion.

  [About the current introduction conductor] The current introduction conductor 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. Conductor. 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 fireproof 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 refractory portion supports the electrode and is interposed between the electrode and the sealing portion to relieve the difference in thermal expansion 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 plural kinds of metals selected from the above group, for example, conductivity such as molybdenum (Mo), tungsten (W) or niobium (Nb). What consists of metals 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.

  [Regarding a pair of electrodes] The pair of electrodes constitutes a high-pressure discharge lamp of the type that generates an electrode-shaped discharge that is sealed in a light-transmitting ceramic hermetic container and arranged 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 where the length A (mm) 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, when the length A of the protrusion is less than 0.3 mm, the instability defined below of the discharge arc tends to exceed 2. Here, the degree of instability of the discharge arc is from 0 to 6, and if the discharge arc becomes unstable when the high-pressure discharge lamp is turned on at the rated lamp power, the degree of instability is 6 and is also unstable at 1.1 times. Then, the degree of instability is 5; below 1.2 is 4; 1.3 is 3; 1.4 is 2; 1.5 is 2; is doing.

  If the instability of the discharge arc is 3 or less, it is determined that there is no practical problem. In the configuration of the present invention that is mercury-free and includes at least one halide of thulium and holmium, the length of the protruding portion of the electrode shaft portion is premised on satisfying the above-mentioned predetermined condition with the electrode mount subcoil described later. If the thickness is 0.3 mm or more, the discharge arc is stable and a practical high-pressure discharge lamp can be 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. In the present invention, the length of the protrusion must be 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 a lump that is entirely filled with a heat-resistant metal, or may be an electrode coil formed by winding a heat-resistant metal wire around the electrode shaft portion. 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.

In the case of a general illumination 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.

  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.

  [Regarding Electrode Mount Subcoil] The electrode mount subcoil is a coil made of a fine wire of heat-resistant metal wound around the outer peripheral surface of the electrode shaft portion and the refractory portion of the current introduction conductor. The electrode and the current introduction conductor are connected in series before being incorporated into the translucent ceramic hermetic container, and the electrode mount subcoil is wound around the above position to constitute the electrode mount. Moreover, tungsten, molybdenum, or the like can be used as the heat-resistant metal forming the electrode mount subcoil.

  In the present invention, the ratio B of the outer diameter of the electrode mount subcoil to the inner diameter of the small-diameter cylindrical portion of the translucent ceramic hermetic container is set to satisfy 0.65 ≦ B ≦ 0.95. And within the above-mentioned range, the length A (mm) of the protruding portion of the electrode satisfies the above-mentioned conditions, so that mercury-free high-pressure discharge containing at least one kind of halide of thulium and holmium and not containing mercury. It was found that the flickering of the discharge arc that is likely to occur in the lamp can be suppressed.

  When 0.65 ≦ B ≦ 0.95 and the ratio B of the outer diameter of the electrode mount subcoil to the inner diameter of the small diameter cylindrical portion is less than 0.65, the capillary formed between the small diameter cylindrical portion and the electrode mount Needs to be increased so that the amount of ionized medium enclosed is increased. And in connection with this, since the amount of impurities entering the inside of the translucent ceramic hermetic container that is mixed into the ionization medium increases, the starting voltage rises and the discharge arc flickers, etc. It is impossible. On the other hand, if the ratio B of the outer diameter of the electrode mount subcoil exceeds 0.95, it is difficult to insert the electrode mount into the small diameter cylindrical portion. The range is preferably 0.75 ≦ B ≦ 0.90.

  It has been shown that the flickering of the discharge arc is affected by the correlation between the length A (mm) of the protruding portion of the electrode and the ratio B of the outer diameter of the electrode mount subcoil to the inner diameter of the small diameter cylindrical portion. That is, as the length A (mm) of the protruding portion increases, the flickering of the discharge arc decreases. However, as the ratio B of the outer diameter of the electrode mount subcoil to the inner diameter of the small diameter cylindrical portion decreases, the flickering of the discharge arc increases. It is necessary to balance the length A (mm) of the protruding portion and the ratio B of the outer diameter of the electrode mount subcoil to the inner diameter of the small diameter cylindrical portion so as to satisfy the above range.

  Also, since the electrode mount subcoil increases the heat capacity of the electrode mount by disposing it, the temperature of the electrode mount is lowered to suppress the reaction between the metal halide and the electrode mount, and the high pressure discharge lamp is Long life can be achieved.

  [About Sealing Part] The sealing part seals the light-transmitting ceramic hermetic container by sealing between the sealing part of the current introduction conductor and the small-diameter cylindrical part. In this case, the above-described sealing may be performed using frit glass, or the sealing portion of the current introduction conductor and the small-diameter cylindrical portion may be directly fused.

  According to the present invention, it is possible to provide a mercury-free high-pressure discharge lamp practical for general lighting applications that has high luminous efficiency and lamp voltage and suppresses flickering of a discharge arc, and an illumination device including the same. .

  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 at 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 electrode mount subcoil SC is formed by winding a thin tungsten wire around the outer peripheral surface of the electrode shaft portion 2a and the refractory portion 2b of the current introduction conductor in the small-diameter cylindrical portion 1b. Yes. Therefore, a slight gap is formed between the outer peripheral surface of the electrode mount subcoil SC 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 electrode mount subcoil SC is d2, the ratio d2 / d1 is the outer diameter of the electrode mount subcoil SC with respect to the inner diameter of the small diameter cylindrical portion 1b of the pole mount subcoil SC. The ratio B. In the present invention, the value of B is set in a range satisfying 0.65 ≦ B ≦ 0.95 as described above.

  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 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.

Further, 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 lamp voltage formation 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).

  Explain about mercury. The present invention is a mercury-free high pressure discharge lamp and therefore does not enclose mercury.

  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.

  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.

  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 portion of the outer tube OT in FIG. 1 and connected to the pair of internal lead-in wires 6a and 6b.
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 cylinder part inside diameter 1.0mm
A pair of electrodes: Distance between electrodes 6.0 mm, length of protrusion A = 1.0 mm,
Electrode mount subcoil: Outer diameter (compared to the inner diameter ratio of the small diameter cylinder part) B = 0.95
Ionization medium: TmI ₃ -NaI = 6.0 mg (content ratio of TmI ₃ 75%), ZnI ₂ = 1.2 mg, Xe4 atmospheric pressure High voltage for starting: 4.0 kV
Base: Commercially available general lighting HID base Electrical characteristics: Lamp voltage 64V, lamp power 100W, ballast uses special ballast Luminous characteristics: Luminous efficiency 90 lm / W, discharge arc instability was zero.

Next, the translucent ceramic hermetic container 1 and the distance between the electrodes having the same basic specifications as those of Example 1 were obtained, and TmI ₃ 3.0 to 9.0 mg, NaI 1.0 to 3.0 mg, ZnI ₂ 0.2 to 2.2 mg, Xe 1 to Metal halides manufactured by varying the pressure at 5 atm, the length A of the projecting part of the electrode shaft from 0 to 1.5 mm, and the outer diameter ratio B of the electrode mount subcoil (to the inner diameter ratio of the small diameter cylindrical part) from 0.64 to 0.96 The result of investigating the instability of the discharge arc of the lamp is shown in FIG.

  FIG. 4 is a graph showing the relationship between the protruding length of the electrode shaft portion and the inner diameter ratio of the outer diameter of the electrode mount subcoil to the inner diameter ratio of the small-diameter cylindrical portion with respect to the instability of the discharge arc in the high-pressure discharge lamp. In the graph, the instability of the discharge arc is a parameter, and the diagonal line is the boundary of the instability, and the numerical value on the boundary indicates the corresponding instability. The region up to the boundary line indicating the instability adjacent to the right side has the same instability.

  As can be understood from FIG. 4, the length A (mm) of the projecting portion of the electrode satisfies 0.3 ≦ A ≦ 1.5, and the inner diameter ratio B of the outer diameter of the electrode mount subcoil to the small-diameter cylindrical portion is 0. By satisfying .65 ≦ B ≦ 0.95, the instability of the discharge arc becomes 2 or less, and the flickering of the discharge arc is remarkably reduced, so that a practical high-pressure discharge lamp can be obtained.

Translucent ceramic hermetic container: Polycrystalline alumina ceramics integral molding, internal volume 0.07cc,
Small diameter cylinder part inside diameter 0.7mm
A pair of electrodes: Distance between electrodes 4.0mm, length of protrusion A = 0.5mm,
Large diameter diameter (vs. small diameter cylindrical diameter ratio) C = 0.86
Electrode mount subcoil: Outer diameter (ratio of inner diameter of small cylinder) B = 0.86
Ionization medium: TmI ₃ -NaI = 6.0 mg (content ratio of TmI ₃ 75%), ZnI ₂ = 1.2 mg, Xe4 atmospheric pressure High voltage for starting: 4.0 kV
Base: Commercially available general lighting HID base Electrical characteristics: Lamp voltage 64V, lamp power 100W, ballast uses special ballast Luminous characteristics: Luminous efficiency 90 lm / W, discharge arc instability was zero.
Electrical characteristics: Lamp voltage 45V, lamp power 30W, ballast uses dedicated ballast Luminous characteristics: Luminous efficiency 88 lm / W

Next, the translucent ceramic hermetic container 1 and the distance between the electrodes having the same basic specifications as in Example 2 are as follows: TmI _{3 3 to} 9 mg, NaI 1 to ₃ mg, ZnI ₂ 0.2 to 2.2 mg, Xe 1 to 5 atm, electrode axis The results of investigating the instability of the discharge arc of metal halide lamps manufactured with various specifications of the protrusion length 0 to 1.5 mm and the outer diameter of the electrode mount subcoil (relative to the small diameter cylindrical portion) 0.64 to 0.96 It was almost the same as shown in FIG. Further, the length A (mm) of the protruding portion of the electrode satisfies 0.3 ≦ A ≦ 1.5, and the inner diameter ratio B of the outer diameter of the electrode mount subcoil to the small diameter cylindrical portion is 0.65 ≦ B ≦ 0. When the specifications of the outer diameter of the large diameter portion 2b of the electrode 2 (to the small diameter cylindrical portion inner diameter ratio) of 0.64 to 0.96 are varied within a range satisfying .95, the ratio C is 0.7 ≦ C ≦ 0.95. Was within the range satisfying the above, the instability of the discharge arc was 2 or less. However, when the ratio C does not satisfy the above formula, the discharge arc instability was 3 or more.

  FIG. 5 is a partial cross-sectional front view of an essential part showing an electrode in a second embodiment for implementing the high-pressure discharge lamp of the present invention. The same parts as those in FIG.

  In this embodiment, the electrode 2 has a projecting portion 2a1 of the electrode shaft portion 2a having a conical shape. The apex angle θ of the cone is preferably set as appropriate within a range of 30 to 120 ° as desired. When the apex angle θ is less than 30 °, the tip portion is excessively heated and easily evaporates, and as a result, the shape of the tip tends to change. Further, when the tip part exceeds 120 °, the difference from the case where the tip part is flat is eliminated.

  Thus, according to this embodiment, arc discharge can be further stabilized.

  FIG. 6 is a cross-sectional view showing a ceiling-embedded downlight as an embodiment for carrying out 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.

The front view which shows the 1st form for implementing the high pressure discharge lamp of this invention Similarly, enlarged cross section of arc tube Similarly enlarged front view of electrode mount A graph showing the relationship between the protruding length of the electrode shaft and the ratio of the outer diameter of the electrode mount subcoil to the inner diameter ratio of the small-diameter cylinder in relation to the instability of the discharge arc in the high-pressure discharge lamp The principal part partial cross section front view which shows the electrode in the 2nd form for implementing the high pressure discharge lamp of this invention Sectional drawing which shows the ceiling embedded downlight as one form for implementing the illuminating device of this invention

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Translucent ceramic airtight container, 1a ... Enveloping part, 1b ... Small diameter cylindrical part, 1c ... Discharge space, 2 ... Electrode, 3 ... Current introduction conductor, 3a ... Sealing part, 3b ... Halogen-resistant part, 4 ... Sealing part, 5 ... Stem, B ... Base, IT ... Arc tube, OT ... Outer tube, SC ... Electrode mount subcoil, SF ... Support frame, SG ... Protective glass, TW ... Proximity conductor, UVE ... Ultraviolet radiation discharge tube

Claims (3)

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-introducing conductors inserted into the inside of the small-diameter cylindrical portion of the translucent ceramic hermetic container, comprising a sealing portion and a refractory portion connected to the tip of the sealing portion;
An electrode shaft portion and a large-diameter portion are provided, the base end of the electrode shaft portion is connected to the tip of the refractory portion of the current introduction conductor, and the tip faces the enclosure portion of the translucent ceramic hermetic container. Protruding portions are disposed near the tip of the electrode shaft portion, the length of the electrode shaft portion protruding from the large diameter portion and protruding in the tube axis direction is 0.3 to 1.5 mm. A pair of electrodes;
The ratio B of the outer diameter to the inner diameter of the small-diameter cylindrical portion of the translucent ceramic hermetic container satisfied 0.65 ≦ B ≦ 0.95, and was wound around the outer peripheral surface of the electrode shaft portion and the refractory portion of the current introduction conductor. An electrode mount subcoil;
Rare gas and metal halide, rare gas is mainly xenon at 1 to 5 atm in terms of 25 ° C., metal halide contains at least one halide of thulium (Tm) and holmium (Ho), and mercury is contained. An ionization medium enclosed in a translucent ceramic hermetic container without containing;
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 the ratio C of the outer diameter of the large-diameter portion to the inner diameter of the small-diameter cylindrical portion satisfies a value of 0.7 ≦ C ≦ 0.95. A lighting device body;
The high-pressure discharge lamp according to claim 1 or 2, which is disposed in the lighting device body;
A lighting circuit for lighting the high-pressure discharge lamp;
An illumination device comprising:

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