JP2007299621A - High-pressure discharge lamp, and illumination device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high pressure discharge lamp in which translucent polycrystalline alumina ceramics of a translucent airtight container is superior in mechanical strength and thermal shock resistance, and an illumination device using this. <P>SOLUTION: The high pressure discharge lamp is provided with surrounding part 1a which is composed of the translucent polycrystalline alumina ceramics and which surrounds a discharge space, and a pair of small diameter cylindrical parts 1b, 1b which extendedly exist from both ends of a tube axial direction, and equipped with the translucent airtight container 1 in which the alumina average particle diameter of the outer surface region R1 in the cross-sectional face of the wall thickness direction of the surrounding part is smaller by 8% or more than the alumina average particle diameter of the residual region R2, a pair of electrodes 2, 2 sealed in the translucent airtight container, and an ionized medium sealed in the translucent airtight container. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a high-pressure discharge lamp including a light-transmitting hermetic container made of a light-transmitting alumina ceramic and a lighting device including the same.

  A ceramic metal halide lamp for liquid crystal backlights having a linear transmittance of 60 to 85% is obtained by using polycrystalline yttrium aluminum garnet (YAG) made of crystals having an average particle diameter of 5 μm or less in a translucent ceramic discharge vessel. Is known (see Patent Document 1).

  Moreover, development which raises the linear transmittance of translucent polycrystalline alumina ceramic is performed (for example, refer nonpatent literature 1).

  On the other hand, in order to obtain a light-emitting tube for a high-intensity discharge lamp made of translucent polycrystalline alumina ceramics with excellent corrosion resistance and strength, the average crystal grain size on the surface is thick. It is known to use polycrystalline alumina that is 2 to 10 times larger than the average crystal grain size of the portion including the center line (see Patent Document 2).

JP-A-10-255719 JP 2004-259447 A K. Morinaga, T. Torikai, K. Nakagawa, and S. Fujino, “lochFabrication of fine α loch-alumina powders by thermaldecomposition of ammonium aluminum carbonate hydro-oxide (AACH)” lochActamaterialia, 48, p4375-4741 (2000)

  However, in the case of the metal halide lamp described in Patent Document 1, it is difficult to obtain a translucent ceramic discharge vessel made of polycrystalline YAG ceramics on an industrial scale and at low cost. Further, a high-pressure discharge lamp provided with a light-transmitting hermetic container made of a light-transmitting ceramic suitable for an automobile headlamp needs to have a structure different from that for a liquid crystal backlight. Patent Document 1 does not disclose this point.

  Non-Patent Document 1 discloses a technique for obtaining polycrystalline alumina ceramics having a high linear transmittance, but does not mention the configuration of a light-transmitting hermetic container of a high-pressure discharge lamp.

  On the other hand, the arc tube for a high-intensity discharge lamp described in Patent Document 2 has a low linear transmittance, so that it is difficult to control the light distribution, and a high degree of light condensing performance is required as in an automobile headlamp. It cannot be used for high-pressure discharge lamps.

  An object of the present invention is to provide a high-pressure discharge lamp in which a light-transmitting polycrystalline alumina ceramic of a light-transmitting hermetic container is excellent in mechanical strength and thermal shock resistance, and an illumination device using the same.

  In addition, another object of the present invention is to provide a high-pressure discharge lamp in which the light-transmitting hermetic container is excellent in transparency and a lighting device using the same.

    A high pressure discharge lamp according to a first aspect of the present invention includes an enclosing portion made of translucent polycrystalline alumina ceramics and surrounding a discharge space, and a pair of small diameter cylindrical portions extending from both ends in the tube axis direction of the enclosing portion. A translucent airtight container in which the alumina average particle size of the outer surface region in the cross section in the thickness direction of the portion is 8% or more smaller than the alumina average particle size of the remaining region; and a pair sealed in the translucent airtight container And an ionization medium enclosed in a translucent airtight container.

  In the first invention, since the distribution of the average particle diameter of alumina in the surrounding portion of the translucent airtight container is configured as described above, the mechanical strength and thermal shock resistance of the surrounding portion are improved. Resistance to tensile stress on the outer surface that is sometimes applied increases, and durability is improved against thermal shocks such as starting and extinguishing. At this time, since the particle size remains relatively large near the inner surface where the temperature is higher, the heat resistance (ease of grain growth, low creep temperature, etc.) due to the small particle size is not inferior. Therefore, higher performance can be achieved than a translucent airtight container formed using ceramics having no particle size distribution.

    A high pressure discharge lamp according to a second aspect of the present invention comprises an enclosing portion made of translucent alumina polycrystalline ceramic and surrounding a discharge space and a pair of small diameter cylindrical portions extending from both ends of the enclosing portion in the tube axis direction. A translucent airtight container in which the pore content of the outer surface region in the cross section in the thickness direction of the portion is 7% or less less than the pore content of the remaining region; a pair of electrodes sealed in the translucent airtight container And an ionization medium enclosed in a translucent airtight container.

  According to the first invention, the translucent airtight container is excellent in mechanical strength and thermal shock resistance by defining the distribution of the average particle diameter of alumina in the cross section in the thickness direction of the surrounding portion within a predetermined range. A lamp and an illumination device using the lamp can be provided.

  According to the second invention, the translucent airtight container is excellent in mechanical strength and thermal shock resistance by defining the pore content distribution in the cross section in the thickness direction of the surrounding portion within a predetermined range. And an illuminating device using the same can be provided.

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

    1 and 2 show a first embodiment for carrying out the high-pressure discharge lamp according to the present invention, FIG. 1 is a sectional view of an arc tube, and FIG. 2 is a thickness direction of a surrounding portion of a translucent airtight container. It is a schematic diagram explaining the alumina average particle diameter distribution in a part of cross section. The first form corresponds to the first invention.

  The high-pressure discharge lamp according to the present embodiment is a metal halide lamp that can be implemented as a high-pressure discharge lamp for various uses such as for general lighting and automobile headlamps. The translucent hermetic container 1, the pair of electrodes 2, 2 , A pair of current introduction conductors 4, 4, a pair of sealing materials 6, 6 and an ionization medium. The translucent airtight container 1, the pair of electrodes 2, 2, the pair of current introduction conductors 4, 4, the pair of sealing materials 6, 6 and the discharge medium are integrated to form a translucent arc tube IT, It is sealed in an outer tube (not shown) and used.

  First, the translucent airtight container 1 will be described in detail below.

  The translucent airtight container 1 is made of translucent polycrystalline alumina ceramics, and includes an enclosing portion 1a and a pair of small diameter cylindrical portions 1b and 1b, and is formed in an integrated structure.

  The surrounding portion 1a is a hollow portion that surrounds the discharge space 1c. In the case of a high-pressure discharge lamp for automobile headlamps, the discharge space 1c preferably has a substantially cylindrical shape. In addition, since it is preferable that the thickness of the region facing at least a pair of electrodes, which will be described later, is substantially uniform, the surrounding portion in this case has a substantially cylindrical shape. However, the outer shape of the surrounding portion and the shape of the discharge space are allowed to have other shapes such as a spherical shape and an elliptical spherical shape as desired. Various values can be selected as the volume of the discharge space 1c formed in the surrounding portion 1a according to the rated lamp power of the high-pressure discharge lamp, the distance between the electrodes, and the like.

  In the present invention, as shown in FIG. 2, the surrounding portion 1a has an alumina average particle diameter of crystal grains in the remaining surface R2 in the outer surface region R1 in the cross section in the thickness direction. It is 8% or smaller than that. In short, the average alumina particle size in the thickness direction of the surrounding portion 1a is small in the outer surface region R1, the average particle size in the remaining region R2 is large, and the relative ratio of the average particle size is 8% or more. It has a uniform average particle size distribution. Note that FIG. 2 shows only a part of the outer surface region R1 and the remaining region R2 continuous to the outer surface region R1, and therefore, the portion on the inner surface side is not shown.

  Further, the outer surface region R1 in the cross section in the thickness direction is a region where the region on the outer surface side is at most less than half of the entire thickness, and is preferably less than or equal to the outer third of the thickness, for example, It is a 20% area. In addition, the cross section in the thickness direction preferably satisfies the above-mentioned conditions in at least the entire main portion in the tube axis direction of the surrounding portion, but is a cross section in the central portion in the tube axis direction of the surrounding portion 1a or in the vicinity thereof. .

  The average particle diameter is obtained by observing a cross section in the thickness direction of the surrounding portion 1a with an electron microscope. If the relative ratio of the average particle diameter is 8% or more, the effects and effects of the first invention are exhibited, but if it is 8% or less, sufficient actions and effects cannot be achieved.

  Further, the surrounding portion 1a preferably has a linear transmittance of 20% or more in the main portion thereof, and an alumina average particle size of the outer surface region R1 is 1.2 μm or less. The smaller the average particle size is, the higher the linear transmittance becomes. When the average particle size is 1.2 μm or less, it becomes easy to increase the linear transmittance to 20% or more. In addition, when the average particle diameter is 1.2 μm or less, if the average particle diameter of the remaining region R2 is 1.3 μm or more, the requirement of the relative ratio of the average particle diameter of the first invention is satisfied.

  Furthermore, the surrounding portion 1a preferably has a pore content in the outer surface region R1 in the cross section in the thickness direction of the surrounding portion that is 7% or more less than the pore content in the remaining region R2. The pore content is evaluated by the number and size of pores in alumina, and the content is determined by observing a cross section in the thickness direction of the surrounding portion with an electron microscope.

  Next, the pair of small diameter cylindrical portions 1b and 1b are connected to the surrounding portion 1a at both ends in the tube axis direction. The inner diameter of the small diameter cylindrical portion 1b is clearly smaller than the inner diameter of the surrounding portion 1a, for example, 1/10 or less. And in the state which the translucent airtight container 1 is not sealed, it has the elongate through-hole extended in a pipe-axis direction inside the small diameter cylinder part 1a, The one end is in the discharge space 1c of the enclosure part 1a. The other end is open to the outside.

  Further, the length of the pair of small diameter cylindrical portions 1b and 1b in the tube axis direction is not particularly limited. The length of the small diameter cylindrical portion 1b is formed to be relatively large, and is extended so as to form a slight gap called a capillary between the shaft portion of the electrode 2 and the inner surface of the small diameter cylindrical portion 1b. be able to. This configuration is suitable when the translucent airtight container 1 is sealed using a glass frit as the sealing material 6. However, when a sealing structure with high heat resistance such as directly sealing the translucent airtight container 1 and the current introduction conductor 4 supporting the electrode 2 without using a glass frit is adopted, By shortening the cylindrical part 1b and raising the coldest part temperature, the luminous efficiency can be improved and the arc tube can be downsized.

  Furthermore, the pair of small-diameter cylindrical portions 1b and 1b can preferably be configured such that the linear transmittance is lower than the linear transmittance in the surrounding portion 1a. Since the linear transmittance of the small-diameter cylindrical portion 1b hardly affects the direct light distribution, it may be lower than the linear transmittance of the surrounding portion 1a.

  By the way, the surrounding part 1a and a pair of small diameter cylinder parts 1b and 1b of the translucent airtight container 1 are continuously integrated. For this reason, the translucent airtight container 1 is not formed with thermal and optical discontinuous portions. According to the most typical structure in this configuration, the surrounding portion 1a and the pair of small diameter cylindrical portions 1b, 1b of the translucent airtight container 1 are formed by integral molding. Moreover, according to the different structure, in the stage before forming the translucent airtight container 1, the whole of the surrounding portion 1a and the pair of small-diameter cylindrical portions 1b, 1b or those portions are used as separate members, respectively. Are prepared by compression molding or pre-sintering, and then each member is incorporated into the shape of the light-transmitting hermetic container 1 in the sintering mold and subjected to main sintering to be adjacent. The alumina particles between the separate members are directly bonded to obtain a light-transmitting hermetic container 1 free from thermal and optical discontinuities. In addition, in the translucent airtight container 1 having a so-called shrink fitting structure, since the thermal and optical discontinuous portions are formed, the object of the present invention cannot be achieved.

  If desired, the translucent airtight container 1 can be formed using translucent polycrystalline alumina ceramics with low creep as follows. That is, the translucent airtight container 1 is formed using translucent polycrystalline alumina ceramics that undergoes mechanical expansion deformation and rupture in 1300 ° C. (minimum 1200 ° C.) for 24 hours at an internal pressure of 50 atm. The hermetic container 1 is operated at a maximum temperature during lighting (measured value under specified conditions) of 900 to 1100 ° C. By using such a translucent airtight container 1, manufacturing cost can be reduced.

  In the above, the temperature of the translucent airtight container 1 was measured as follows. That is, the outer tube of the high-pressure discharge lamp or the outer tube and the protective tube are removed, and only the arc tube IT and the arc tube are turned on in the same airtight container as the atmosphere in the outer tube of the high-pressure discharge lamp. The maximum temperature of the arc tube IT at the same lamp power (in many cases, the temperature at the center of the enclosure) is measured. For the measurement, a radiation thermometer TMZ54S-2300G manufactured by Japan Sensor was used.

  In the above case, if the average particle diameter of alumina in at least the surrounding portion 1a of the light-transmitting airtight container 1 is 3 μm or less, preferably 1.2 μm or less, the light-transmitting airtightness is high because the linear transmittance is high and transparent. A container is obtained.

  Furthermore, the translucent alumina ceramics having a relatively large average particle diameter of alumina used in the past do not change in shape even at a temperature of about 1200 to 1300 ° C. or higher, but the average particle diameter of alumina as described above. It was found that expansion and deformation occur at the above temperature when becomes smaller. However, if the operating temperature of the translucent airtight container 1 is set low as described above, it can be lit without causing expansion or deformation.

  Next, the pair of electrodes 2 and 2 will be described.

  The pair of electrodes 2 and 2 are disposed so as to be sealed in the translucent airtight container 1 and face the discharge space 1c inside. In general, the distance between the electrodes formed between the pair of electrodes 2 and 2 is preferably 5 mm or less. In the case of a high-pressure discharge lamp for an automobile headlamp, the center value is 4.2 mm. Has been.

  Further, the constituent material of the electrode 2 is fire-resistant and has a conductive metal such as pure tungsten (W), a dopant (for example, scandium (Sc), aluminum (Al), potassium (K) and silicon (Si). 1) or a doped tungsten containing thorium oxide, rhenium (Re) or tungsten-rhenium (W-Re) alloy, or the like. Can do.

  Furthermore, in the case of a small high-pressure discharge lamp, a straight rod-shaped wire or a wire having a large diameter portion at the tip can be used as the electrode 2. In the case of a medium or large electrode 2, an electrode coil made of an electrode constituent material can be wound around the tip of the electrode shaft. The pair of electrodes 2 and 2 have the same structure when operating with an alternating current. However, when operating with direct current, since the temperature of the anode is generally large, the heat radiation area is larger than that of the cathode, and thus the main part can be thick.

  In addition, the pair of electrodes 2 and 2 are inserted into the small-diameter cylindrical portions 1b and 1b of the translucent airtight container 1 at the intermediate portion and the base end thereof, so that the inner surface of the small-diameter cylindrical portion 1b is interposed as described above. A slight gap called a capillary can be formed. The base ends of the pair of electrodes 2 and 2 are connected to and supported by the distal end of a current introduction conductor 3 to be described later.

  Next, the ionization medium will be described.

  The ionization medium includes at least a starting gas and an ionization medium that contributes to light emission. Note that the start gas may serve as a medium that contributes to light emission if desired. It preferably also includes an ionization medium for forming a lamp voltage.

  The starting gas also acts as a buffer gas, and can enclose one kind of group such as xenon (Xe), argon (Ar), and neon (Ne) alone, or a mixture of plural kinds. The enclosure pressure of the rare gas can be appropriately set according to the use of the high pressure discharge lamp.

  Among rare gases, xenon has a relatively low thermal conductivity because its atomic weight is larger than other rare gases, so that it is sealed at 0.6 atm or more, preferably at least 5 atm. This contributes to the formation of the lamp voltage and emits white visible light when the vapor pressure of the halide is low, thereby contributing to the rise of the luminous flux, which is effective in the case of a high-pressure discharge lamp for a headlamp. In this case, the preferable sealing pressure of xenon is 6 atmospheres or more, more preferably in the range of 8 to 16 atmospheres. For this reason, it contributes to luminous flux rise and light color rise immediately after lighting, and can satisfy the standard of white light emission as an HID light source for automobile headlamps immediately after lighting.

  The medium that contributes to light emission is mainly composed of a halide of a light emitting metal, and it is allowed to enclose the light emitting metal as it is if desired. In the present invention, the luminescent metal is not particularly limited, but as a preferred example, a thulium (Tm) halide can be mainly encapsulated.

  Thulium halide is a luminescent metal halide suitable as a mercury-free lamp, and mainly emits visible light by discharge. Further, thulium halide can be sealed at a maximum sealing ratio in the ionization medium sealed in the light-transmitting hermetic container 1, preferably 40 to 90% by mass in addition to this condition. Thulium halide itself has a high vapor pressure, which is an ionization medium for forming a lamp voltage, which will be described later, and is itself a potential between electrodes 2 and 2 in the presence of a metal halide that emits less visible light. It has the effect of increasing the gradient and hence the lamp voltage.

  In addition, thulium halide has a low vapor pressure, but the thulium emission peak coincides with the peak of the visibility curve. Therefore, thulium halide is a luminescent metal that is extremely effective for improving the luminous efficiency. The emission intensity of thulium greatly depends on the operating temperature during lighting of the high-pressure discharge lamp, and the efficiency becomes maximum under the condition that the coldest part temperature is about 800 ° C. When the translucent airtight container 1 is made of translucent ceramics, there is no problem in operation under conditions where the coldest part temperature is about 800 ° C., and the chemical resistance is strong. The inclusion of the halide does not adversely affect the lamp life and the luminous flux maintenance factor. That is, thulium halide is a luminescent metal halide suitable for a high-pressure discharge lamp using an airtight container made of translucent ceramics.

  In addition to the above, other luminescent metal halides allowed to be sealed include the following.

  1. (Alkali Metal) When the alkali metal is encapsulated, it is allowed within a range of less than 10% by mass with respect to all metal halides encapsulated in the translucent airtight container 1. When the sealing ratio of the alkali metal is 10% by mass or more, the lamp voltage tends to decrease, which is not preferable from the viewpoint of forming the lamp voltage. However, if the sealing ratio of the alkali metal is less than 10% by mass, a decrease in lamp voltage is suppressed to the minimum, while light emission efficiency, lamp life improvement, and light color adjustment, particularly color deviation improvement are possible. From such a point of view, when a required lamp voltage can be ensured, sealing is permitted within the above range. In addition, Preferably it is 2-8 mass%, More preferably, it is 3-7 mass%, More preferably, it is 4-6 mass%. Further, as the alkali metal, it is possible to selectively enclose mainly sodium (Na), but / or if desired, and / or at least one of cesium (Cs) and lithium (Li).

  Sodium (Na) mainly contributes to the improvement of luminous efficiency. Cesium (Cs) contributes to the improvement of life characteristics by optimizing the discharge arc temperature. Lithium (Li) contributes to the improvement of red color rendering.

  2. (Other Rare Earth Metal Halides) In addition to thulium halides, the following metal halides can be encapsulated mainly as luminescent metal halides. One or a plurality of halides of rare earth metals in the group consisting of praseodymium (Pr), cerium (Ce), holmium (Ho), neodymium (Nd) and samarium (Sm).

  The rare earth metal is useful as a luminescent metal next to thulium halide, and is allowed to be encapsulated at an encapsulation ratio of a predetermined amount or less. That is, any of the rare earth metals has an infinite number of bright line spectra in the vicinity of the peak wavelength of the visibility characteristic curve, and thus can contribute to an improvement in luminous efficiency.

  In addition, when the rare earth metal halide is added, it is preferable that the encapsulation ratio with respect to the total ionization medium including the thulium (Tm) halide is 50 mass% or more.

  3. (Thallium or / and indium halide) The thallium (Tl) and / or indium (In) halide is selectively encapsulated as a secondary component for the purpose of obtaining a desired color rendering property and / or color temperature. It is acceptable. Indium is also effective as an ionization medium for forming a lamp voltage.

  The thallium (Tl) halide can add a green component of thallium having an emission line at a wavelength of 535 nm during light emission. In addition, it is desirable that the enclosure ratio range of thallium halide that can be generally adopted is less than 30% by mass with respect to all the metal halides to be enclosed. When the enclosure ratio range of thallium halide is 30% by mass or more, the decrease in luminous efficiency becomes significant. In addition, it is preferable to enclose within a range of less than 15% by mass.

  Further, by adding indium (In) halide, the blue component can be increased during light emission of the halide, and also contributes to the formation of a lamp voltage.

  As the halogen of each luminescent metal halide described above, iodine is suitable because it has moderate reactivity. However, if desired, either bromine or chlorine may be used, and iodine, bromine and chlorine may be used. Two or more desired ones may be used.

  Next, as a lamp voltage forming ionization medium, when a mercury-free high-pressure discharge lamp is obtained, it is preferable to enclose a metal halide having a high vapor pressure and low visible light emission as described above. In this case, it is preferable not to contain mercury (Hg) at all for the purpose of reducing environmentally hazardous substances, but it is acceptable even if it is contained to the extent of impurities. Further, when obtaining a high-pressure discharge lamp containing mercury, mercury is enclosed.

  In the case of mercury-free, for example, the following metals are effective to be sealed as an ionization medium for forming a lamp voltage. That is, zinc (Zn), aluminum (Al), magnesium (Mg), iron (Fe), cobalt (Co), chromium (Cr), nickel (Ni), manganese (Mn), aluminum (Al), antimony (Sb) ), Beryllium (Be), rhenium (Re), gallium (Ga), titanium (Ti), zirconium (Zr), and hafnium (Hf). Since each metal halide has a high vapor pressure, a large cross-sectional area of collision with electrons, and a large ionization potential, in combination with the light-transmitting hermetic vessel 1 described above, a lamp voltage can be formed instead of mercury. It is a material suitable as an ionization medium for use.

  In the present embodiment, the arc tube IT includes a current introduction conductor 4 and a sealing material 6 in addition to the above-described components.

  The current introduction conductor 4 has a function for supplying power to the electrode 2, a function for sealing the translucent airtight container 1 in cooperation with the small-diameter cylindrical portion 1 b and a sealing material 6 described later, and a function for supporting the electrode 2. It is a member. Then, the base end portion is exposed to the outside from the end portion of the small diameter cylindrical portion 1 b and connected to a lighting circuit (not shown), and the tip end portion is connected to the base end of the electrode 2. The distal end portion of the current introduction conductor 4 is inserted into the small diameter cylindrical portion 1b of the translucent airtight container 1, and is further connected to the proximal end of the electrode 2 inside the small diameter cylindrical portion 1b.

  Moreover, the diameter of the part inserted in the small diameter cylinder part 1b of the current introduction conductor 4 can be made larger than the diameter of at least the base end part of the electrode 2, preferably the electrode shaft. As a result, the diameter of the electrode 2 or the electrode shaft 2a can be set to an optimum size without being affected by the diameter of the current introduction conductor 4, and erosion due to retention of the ionized medium is reduced.

  Further, the entire current introducing conductor 4 may be formed of a sealing conductive member, or may be formed of a series connection structure of a sealing conductive member and a halogen-resistant conductive member. When the entire current introduction conductor 4 is formed of a sealing conductive member, it is a matter of course that the sealing conductive member takes into account the above three functions. On the other hand, when the current introduction conductor 4 is formed of a serially connected structure of a sealing conductive member and a halogen-resistant conductive member, the sealing conductive member cooperates with the small-diameter cylindrical portion and a sealing material 6 described later. It is in charge of the function of sealing the translucent airtight container 1, the halogen-resistant conductive member is in charge of supporting the electrode, and both members are in charge of supplying power to the electrode.

  As the sealing conductive member, a conductive member having a thermal expansion coefficient close to that of the electrode is preferably used. For example, a material selected from niobium (Nb), tantalum (Ta), platinum (Pt), cermet, and the like can be used. Niobium is suitable for the light-transmitting polycrystalline alumina ceramics in terms of thermal expansion coefficient.

  As the halogen-resistant conductive member, a member having fire resistance that can withstand heat transfer from the electrode and a thermal expansion coefficient close to that of the electrode constituent material is preferably used. For example, it can be selected from tungsten (W), molybdenum (Mo), cermet and the like. The cermet is formed by firing a mixture of ceramic particles and refractory conductive metal (for example, Mo or W) powder.

  In order to connect the electrode 2 in advance to the current introduction conductor 4 to support the electrode 2 and facilitate assembly with respect to the translucent airtight container 1, for example, both can be integrated by butt welding to constitute an electrode mount. . Further, when the current introduction conductor 4 is formed of a sealing conductive member and a halogen-resistant conductive member, they can be integrated by butt welding.

  The sealing material 6 is made of high melting point frit glass or the like, and enters between the inner surface of the small-diameter cylindrical portion 1b of the translucent airtight container 1 and the current introduction conductor 4 to seal the translucent airtight container 1 in an airtight manner. . In order to perform this sealing, a pellet of the sealing material 6 is applied around the current introduction conductor 4 at the end of the small-diameter cylindrical portion 1b and is heated and melted as is adopted as a general method. be able to. If it does so, since the sealing material 4 fuse | melted at high temperature will approach into the slight clearance gap formed between the inner surface of the small diameter cylinder part 1b, and the introductory conductor 3, it will solidify. In addition, since the sealing material 4 covers the site | part which functions for sealing of the introductory conductor 3, even if it is a substance inferior to halogen resistance like niobium, it is satisfactory.

    Next, a second mode for carrying out the high-pressure discharge lamp of the present invention will be described. The second form corresponds to the second invention. The lamp shape is the same as in FIG. 1, and will be described with reference to FIG.

  The second form is the first except that the pore content of the outer surface region in the cross section in the thickness direction of the surrounding portion 1a of the translucent airtight container 1 is 7% or more less than the pore content of the remaining region. It is allowed to have the same configuration as that of the embodiment.

  Thus, in the second embodiment, by reducing the pore content of the outer surface region R1 by 7% with respect to the remaining region R2, the translucent polycrystalline alumina ceramics as in the first embodiment are used. Improves mechanical strength and thermal shock resistance.

Translucent airtight container: Integrated molding
Enclosure; length 6mm, inner diameter 5mm, wall thickness 0.5mm,
The average particle size is 25μm on the outer surface area (20% of wall thickness), the remaining area is 30μm,
85% average pore content ratio of the outer surface area (20% of wall thickness) to the remaining area,
Linear transmittance 10%
Small diameter cylindrical part: 0.7mm inner diameter, 0.5mm thickness, 12mm length, 7% linear transmittance
Discharge medium: Noble gas; Ar 0.4 atm, Hg 1 mg, NaI-TlI-InI (50:40:10 wt%): 3 mg,
ZnI ₂ : 0.5mg

Translucent airtight container: Integrated molding
Enclosure: length 8mm, inner diameter 2.9mm, wall thickness 0.5mm,
Average particle size is 0.6μm for the outer surface area (20% of wall thickness), 0.7μm for the remaining area,
85% average pore content ratio of the outer surface area (20% of wall thickness) to the remaining area,
Linear transmittance 30%,
Small diameter cylindrical part: 0.7mm ID, 0.5mm wall thickness, 12mm length, 20% linear transmittance
Discharge medium: Noble gas; Xe 10 atm, TmI ₃ -TlI-NaI-ZnI ₂ (50: 20: 20: 10 wt%): 3 mg,

Translucent airtight container: Integrated molding
Enclosure: length 8mm, inner diameter 2.9mm, wall thickness 0.5mm, linear transmittance 30%,
Alumina average particle size 0.5-1.0μm
Small diameter cylindrical part: 0.7mm inner diameter, 0.5mm thickness, 12mm length, 20% linear transmittance,
Alumina average particle size 0.5-1.0μm
Discharge medium: Noble gas; Xe 10 atm, TmI ₃ -TlI-NaI-ZnI ₂ (50: 20: 20: 10 wt%): 3 mg,
Translucent airtight container Operating temperature: 1050 ℃
Translucent airtight container deformation expansion start temperature (24h): 1300 ℃

FIG. 3 is a schematic diagram of an automobile headlamp as an embodiment for carrying out the lighting device of the present invention. In the figure, 11 is a headlamp body, 12 is a high pressure discharge lamp lighting device, and 13 is a high pressure discharge lamp.

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

  The high pressure discharge lamp lighting device 12 has a circuit configuration shown in FIG. 4 and includes a main lighting circuit 12A and a starter 12B.

  The high-pressure discharge lamp 13 is mounted on the lamp socket and lights up.

Sectional drawing which shows the 1st form for implementing the high pressure discharge lamp of this invention Similarly, a schematic diagram for explaining the alumina average particle size distribution in a part of the cross section in the thickness direction of the surrounding portion of the light-transmitting hermetic container The conceptual diagram which shows the motor vehicle headlamp as one form for implementing the illuminating device of this invention

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Translucent airtight container, 1a ... Enclosing part, 1b ... Small diameter cylinder part, 1c ... Discharge space, 2 ... Electrode, 4 ... Current introduction conductor, 6 ... Sealing material, IT ... Arc tube

Claims (6)

An outer surface of a cross section in the wall thickness direction of the enclosure portion, which is made of translucent polycrystalline alumina ceramics and includes a surrounding portion surrounding the discharge space and a pair of small diameter cylindrical portions extending from both ends of the surrounding portion in the tube axis direction A translucent airtight container having an alumina average particle size in the region of 8% or more smaller than the alumina average particle size in the remaining region;
A pair of electrodes sealed in a translucent airtight container;
An ionization medium enclosed in a translucent airtight container;
A high-pressure discharge lamp comprising: An outer surface of a cross section in the wall thickness direction of the enclosure portion, which is made of translucent polycrystalline alumina ceramics and includes a surrounding portion surrounding the discharge space and a pair of small diameter cylindrical portions extending from both ends of the surrounding portion in the tube axis direction A translucent airtight container having a pore content in the region of 7% or more less than the pore content in the remaining region;
A pair of electrodes sealed in a translucent airtight container;
An ionization medium enclosed in a translucent airtight container;
A high-pressure discharge lamp comprising:   The envelope portion has a linear transmittance higher than that of the small-diameter cylindrical portion and exceeds 20%, and an average particle diameter of alumina is 1.2 μm or less. The high-pressure discharge lamp described.   2. The high-pressure hermetic container according to claim 1, wherein the pore content of the outer surface region in the cross section in the thickness direction of the surrounding portion of the translucent airtight container is 7% or more less than the pore content of the remaining region. Discharge lamp.   3. The translucent airtight container according to claim 2, wherein the alumina average particle size of the surface region in the cross section in the thickness direction of the surrounding portion is 8% or more smaller than the alumina average particle size of the remaining region. High pressure discharge lamp. A lighting device body;
A high-pressure discharge lamp according to any one of claims 1 to 5 disposed in a lighting device body;
A lighting device for lighting the high-pressure discharge lamp;
An illumination device comprising:

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