JP2008192475A - High-pressure discharge lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact high-pressure discharge lamp equipped with an outer tube, with an ultraviolet-ray generating source arranged at a position effective for start-up help against an arc tube equipped with a translucent ceramic airtight container. <P>SOLUTION: The high-pressure discharge lamp is provided with a nearly cylindrical outer tube OT, an arc tube IT equipped with a translucent ceramic airtight container 1 having an envelope part 1a and a pair of small-diameter cylinder parts 1b1, 1b2, electrodes 2, current-leading conductors 3, sealing parts 4 and a discharge medium, a support member SF extended between an inner face of the outer tube and the arc tube to support the latter, and an ultraviolet-ray generating source UVE equipped with a small vessel, discharge gas, inner electrodes 23 sealed inside the small vessel and connected to a site to be of the same potential as one of the electrodes of the arc tube, and outer electrodes 24 closely enveloping the small vessel and connected to a site to be of the same potential as the other electrode of the arc tube, and with its main body part arranged between an inner face of the outer tube and one of the small-diameter cylinder parts at a position roughly in opposition to the support member. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a relatively small high-pressure discharge lamp having a translucent ceramic hermetic container.

  A metal halide lamp is widely used as a light source for general illumination and industrial use because a high-pressure discharge lamp with high color rendering and high efficiency can be obtained with a metal halide at a desired color temperature. There is a demand for a small high-pressure discharge lamp with relatively low lamp power for indoor commercial lighting, etc., and a quartz glass arc tube with a single-sealed structure or a translucent ceramic arc tube with a double-sided sealed structure A high-pressure discharge lamp or the like disposed in an outer tube having a sealing structure is used.

  High-pressure discharge lamps equipped with arc tubes made of translucent ceramics can be made smaller than quartz glass because translucent ceramics are superior in heat resistance and corrosion resistance, and have relatively high efficiency and color rendering. Therefore, it is suitable for a high pressure discharge lamp with a small lamp power.

  On the other hand, in order to assist in starting the high-pressure discharge lamp, there is known a small ultraviolet ray generation source disposed at a position close to the lower side of the arc tube in the outer tube (see Patent Document 1). This ultraviolet ray generation source encloses an ultraviolet radiation discharge gas in a small ultraviolet permeable container, and discharges between the internal electrode sealed in the small container and the external electrode surrounding the small container close to the outer surface. To generate ultraviolet rays. Since the high-pressure discharge lamp has an ultraviolet light source, the start-up voltage is lowered as a result of assisting the start-up, so that the start-up is facilitated.

JP 2003-151499 A

  If the thickness and length of the outer tube of the high-pressure discharge lamp are reduced as much as possible, the outer tube can be mounted on, for example, a spotlight or downlight for a halogen bulb, which is preferable in various applications such as commercial lighting.

  However, in the case of the above-described high-pressure discharge lamp provided with the ultraviolet ray generation source, it is difficult not only to reduce the size of the lamp with a conventionally known component arrangement, but also an effective arrangement for assisting starting the arc tube of the ultraviolet ray generation source. could not.

  The present invention provides a compact high-pressure discharge lamp provided with an outer tube while arranging an ultraviolet ray generation source at an effective position for assisting start-up with respect to an arc tube provided with a light-transmitting ceramic hermetic container. Objective.

    A high-pressure discharge lamp according to the present invention includes a substantially cylindrical outer tube; a surrounding portion that surrounds a discharge space; and a pair of small-diameter cylindrical portions that communicate with both ends of the surrounding portion; a pair of small-diameter cylindrical portions A pair of electrodes sealed in a light-transmitting ceramic hermetic container with their tips spaced apart and facing each other, and a pair of small-diameter cylindrical portions, respectively. A pair of current introduction conductors connected to the base end side, a small-diameter cylindrical portion, and a pair of seal portions that seal the translucent ceramic hermetic container between the current introduction conductors and the translucent ceramic hermetic container, respectively. An arc tube provided in the outer tube with a discharge medium containing a metal halide and a rare gas; a support member extending between the inner surface of the outer tube and the arc tube and supporting the arc tube; Sex small container, Discharge gas that is sealed inside a container and emits ultraviolet light during discharge, sealed inside a small container, and close to the internal electrode and small container connected to the same potential as one electrode of the arc tube An external electrode connected to a portion having the same electric potential as the other electrode of the arc tube, and at a position generally opposed to the support member, the main portion being an inner surface of the outer tube and one small diameter tube of the arc tube And an ultraviolet ray generation source disposed between the two portions.

  [Outer tube] The outer tube accommodates a later-described arc tube, for example, keeps the arc tube warm, mechanically protects it, exhibits a light diffusing action, or exhibits an ultraviolet cut function. For one or more purposes. Further, the outer tube is allowed to be composed of multiple tubes.

  Therefore, the inside of the outer tube is configured to be kept airtight with respect to the atmosphere outside the lamp or communicate with the outside air according to the purpose. As a high-pressure discharge lamp for general illumination, the inside of the outer tube is generally set to a vacuum or an inert gas (for example, nitrogen or argon) atmosphere.

  In the present invention, the outer tube has a substantially cylindrical shape. When the shape of the outer tube is substantially cylindrical, it is excellent in mountability to a lighting device such as a downlight or a spotlight that uses a halogen bulb as a light source.

  The constituent material of the outer tube is not particularly limited. For example, the outer tube can be formed using hard glass, semi-hard glass, quartz glass, or the like. In the case of quartz glass, one having an ultraviolet cutting performance or one having ultraviolet transparency can be selected and used. If desired, the outer tube can be formed using translucent ceramics.

  A light diffusing action can be imparted to the outer tube. For this reason, a light diffusion film such as a phosphor film or a silica film can be conventionally formed on the inner surface of the outer tube as desired. However, it goes without saying that a transparent outer tube may be used as is known.

  Further, in the small high-pressure discharge lamp as described above, when the maximum outer diameter of the outer tube exceeds 16 mm, the radiant heat received from the outer tube of the arc tube during lighting is reduced, and the coldest part temperature of the high-pressure discharge lamp is reduced. The desired value cannot be reached. As a result, desired lamp characteristics cannot be obtained.

  The shape of the outer tube is not particularly limited as long as the portion covering the periphery of the arc tube has a substantially cylindrical shape. Therefore, it is possible to adopt a shape such as a BT type valve or a T type valve that is generally used. However, a T-type valve is suitable for further downsizing the outer tube.

  In one embodiment of the present invention, the outer tube has a maximum outer diameter of 16 mm or less. This is because in a small high-pressure discharge lamp with a rated lamp power of 100 W or less, preferably 70 W or less, and practically about 20 W or more, if the maximum outer diameter is 16 mm or less, the size can be reduced. In terms of the lower limit of the maximum outer diameter, when the rated lamp power is 20 to 30 W, it is possible to realize a maximum outer diameter of about 10 mm.

  Further, in the small high-pressure discharge lamp as described above, when the maximum outer diameter of the outer tube exceeds 16 mm, the radiant heat received from the outer tube of the arc tube during lighting is reduced, and the coldest part temperature of the high-pressure discharge lamp is reduced. The desired value cannot be reached. As a result, desired lamp characteristics cannot be obtained.

    [About the arc tube] In the present invention, the arc tube includes a translucent ceramic hermetic container, a pair of electrodes, a pair of current introduction conductors, a pair of seal portions, and a discharge medium.

  The surrounding portion bulges out and a discharge space is formed therein. Note that translucency means that it is only necessary to transmit at least a light-emitting component in a desired wavelength region to the outside from radiation generated by discharge. Moreover, the translucency should just have a grade which functions without a problem as a translucent ceramic airtight container in the normal operation state of a high pressure discharge lamp.

  The small-diameter cylindrical portion communicates with both ends of the surrounding portion, and a slight gap is formed between the electrode and / or current introduction conductor inserted therein and the inner surface of the small-diameter cylindrical portion, as will be described later. Therefore, by setting the length of the small-diameter cylindrical portion to an appropriate value, the liquid phase halide stays inside a slight gap during lighting, and acts as a so-called capillary, so that the translucent ceramic hermetic container The coldest part can be formed, or the temperature of the sealing part can be maintained at a predetermined temperature. The electrode and the current introduction conductor will be described later.

  However, in the present invention, although the small diameter cylindrical portion is provided, it is not an essential requirement that the small diameter cylindrical portion forms a capillary.

  Next, as a constituent material of the translucent ceramic hermetic container, for example, a single crystal metal oxide such as sapphire, a polycrystalline metal oxide, such as a translucent hermetic aluminum oxide, yttrium-aluminum garnet ( YAG), yttrium oxide (YOX), and polycrystalline non-oxide such as aluminum nitride (AlN) can be used. The inner volume of the translucent ceramic hermetic vessel, that is, the volume of the discharge space, can be set to various values according to the rated lamp power of the high-pressure discharge lamp. In addition, the discharge space may have various shapes such as a cylindrical shape, a spherical shape, and an elliptical spherical shape.

    (About a pair of electrode) A pair of electrode is sealed by the translucent discharge container, and the front-end | tip is mutually spaced apart and faces discharge space. The electrode can be formed using a refractory metal such as tungsten (W), doped tungsten, thorium-containing tungsten, rhenium (Re), rhenium-tungsten alloy, or molybdenum (Mo). Further, the electrode can be formed using a part of the base end side or the like using a different kind of refractory metal or cermet. For example, the main part of the electrode is made of tungsten, and the base end part is made of molybdenum or cermet. Further, the electrode can be constituted of an elongated electrode shaft portion and an electrode main portion disposed at the tip portion of the electrode shaft portion. In this case, the electrode main portion is a portion that is disposed at the tip of the electrode shaft and mainly functions as a cathode and / or an anode, and constitutes the tip of the electrode. In addition, the electrode main part can be wound with, for example, a tungsten coil, if necessary, in order to increase its surface area and improve heat dissipation.

    (About the current introduction conductor) The current introduction conductor is a means for supplying a current to the pair of electrodes. The current introduction conductor is inserted into the inside from the open end of the small-diameter cylindrical portion, and the distal end is connected to the proximal end of the electrode. Is exposed to the outside from the small diameter cylindrical portion. The current introduction conductor connected to the electrode can be led out from the translucent ceramic hermetic container. The current introduction conductor seals the translucent ceramic discharge vessel in cooperation with the seal portion. As the current introduction conductor, a conductive substance having a thermal expansion coefficient close to the material of the translucent ceramic hermetic container, such as niobium (Nb), tantalum (Ta), or cermet in the case of translucent alumina ceramics, is used. Is preferred.

    (About a pair of seal | sticker part) While a pair of seal | sticker part is a means for sealing a translucent ceramic airtight container between a small diameter cylinder part and an electric current introduction conductor, it becomes a feed path to an electrode. In general, the seal portion is often used in a structure in which a ceramic sealing compound called frit glass is heated and melted to seal between the small-diameter cylindrical portion and the current introduction conductor. However, in the present invention, various known sealing means can be appropriately employed in addition to the above means.

    (Discharge medium) The discharge medium is composed of at least a metal halide and a starting gas. In addition, a lamp voltage forming material can be preferably included.

  In the metal halide, the metal halide includes a halide of a luminescent metal. As the luminescent metal halide, known various metals and metal halides of combinations thereof can be used.

  The starting gas contributes to starting discharge at least when starting the high-pressure discharge lamp. However, the specific gas type is not limited. In the case of a high-pressure discharge lamp for general illumination, a mixed gas of neon (Ne) and argon (Ar) is preferable. The sealing pressure of the starting gas is generally 8 to 80 kPa. If it is less than 8 kPa, starting becomes difficult as can be understood from the Paschen curve. Moreover, when it exceeds 80 kPa, a starting voltage will become high and will exceed the pressure | voltage resistance of a nozzle | cap | die.

  The lamp voltage forming substance is a discharge medium that mainly contributes to forming a voltage appearing between a pair of electrodes during lighting, and mercury and / or metal halide can be used. As the metal halide as the lamp voltage forming substance, a metal halide having a relatively high vapor pressure can be used.

  [About the Support Member] The support member is a means for ensuring that at least the arc tube is held in a predetermined position in the outer tube. For this purpose, a part contacts the inner surface of the outer tube, preferably elastically. Allow to do. For example, at the tip (top) side of the outer tube, it is always in contact with the inner surface of the outer tube or the inner surface of the exhaust tip off portion, or it is contacted during vibration or impact so as to alleviate the effect on the arc tube Thus, the support member can be configured. In this case, the current introduction conductor can also be used as a part of the support member if desired.

  However, in order to support the arc tube more stably in addition to the support member as desired, it is supported on the stem portion at the base end portion (generally, the end portion to which the base is attached) of the outer tube as desired. Or can be supported by an internal introduction line introduced from the stem portion into the outer tube or a connection line welded to the internal introduction line.

  Further, the support member may have a unified structure, but may have a structure divided into a plurality of parts. In the latter case, the support member can be constituted by a first support member that supports one end of the arc tube and a second support member that supports the other end.

  Furthermore, the support member is made of a metal such as molybdenum (Mo), iron (Fe), nickel (Ni), cobalt (Co), copper (Cu), and aluminum (Al), or an alloy based on them, such as stainless steel, It can be formed using Ni-Cu alloy, brass or the like.

  [Ultraviolet generation source] The ultraviolet generation source includes a small container, a discharge gas, an internal electrode, and an external electrode, and is a means for generating ultraviolet rays during discharge to assist the start of the high-pressure discharge lamp. Allow configuration.

  The small container can be formed of a small-diameter cylindrical capsule such as an ultraviolet-transmissive fire-resistant member, such as quartz glass. As the discharge gas, an ultraviolet radiation discharge gas can be used during discharge of argon (Ar) or the like. The internal electrode is sealed inside the small container and is made of, for example, molybdenum foil. The external electrode surrounds, preferably in close proximity to, the small container. Thus, when a starting voltage of a high-pressure discharge lamp is applied between the internal electrode and the external electrode, discharge is first generated in the small container and ultraviolet rays are generated.

  In the present invention, the ultraviolet ray generation source is disposed in the outer tube in the following manner. In other words, the main part of the ultraviolet ray generation source is disposed between the inner surface of the outer tube and one small-diameter cylindrical portion of the arc tube at a position generally facing the support member.

  Note that the position that generally faces the support member is a position that directly faces the support member around the tube axis of the arc tube, in other words, a position that has a relationship of 180 ° from the support member and an angle of this position ± A position within the range of 60 °. Within this angular range, the arc tube, the support member, and the ultraviolet light source can be easily stored in the outer tube while maintaining the required relationship and easily connected. However, the angular range is preferably in the range of 180 ± 45 °. If the arrangement of the ultraviolet ray generation source with respect to the support member deviates from a position generally facing the support member, it becomes difficult to electrically connect the internal electrode and the external electrode and to seal the outer tube. Moreover, if it is in the said preferable range, the electrical connection of an internal electrode and an external electrode and the sealing of an outer tube will become easy, and the manufacturability of a high pressure discharge lamp will further improve.

  The main part is a main part of the small container of the ultraviolet ray generation source, and mainly determines the physical size of the ultraviolet ray generation source.

  The small container is an ultraviolet light transmissive material, for example, a bottomed cylindrical shape with one end opened, and can be formed using a quartz glass tube having a considerably small diameter as compared with a translucent ceramic hermetic container. The preferred size of the small container is as follows. That is, the maximum outer diameter satisfies one of the conditions of 4 mm or less and 1/4 or less of the maximum outer diameter of the outer tube. The length is not more than 6 times the maximum outer diameter of the small container. By satisfying these conditions, it becomes easy to dispose the arc tube, the support member, and the ultraviolet ray source in a required relationship in an outer tube having a maximum outer diameter of 16 mm or less.

  The internal electrode and the external electrode can be formed using a metal excellent in workability and heat resistance such as molybdenum (Mo), tungsten (W), tantalum (Ta), and niobium (Nb).

  The internal electrode can be made of, for example, a foil-like or linear conductive metal sealed inside a small container. In order to seal the internal electrode in the small container, the open end of the small container can be pinched or shrink sealed with the introduction conductor having the internal electrode connected to the tip. However, the introduction conductor may be extended to serve as an internal electrode. Then, it becomes possible to further reduce the size of the ultraviolet ray generation source.

  The external electrode surrounds the small container and opposes the internal electrode with the wall of the small container and the discharge gas interposed therebetween. The above-described surrounding mode is preferably a coil shape having about 1 to 5 turns. If the number of turns is within this range, the small container can be surrounded to easily cause discharge inside the small container, and the generated ultraviolet rays can be effectively radiated to the outside. If it is less than about 1 turn, it becomes difficult to cause discharge throughout the inside of the small container. In addition, about 1 turn means that it may be less than 1 turn as long as it can be said that it is not only complete 1 turn but about 1 turn. On the other hand, when the number of turns exceeds 5, the ratio of the outer surface of the small container covered by the external electrode increases so that the derivation of ultraviolet rays is likely to be hindered.

  For the external electrode, a conductor having an appropriate form such as a linear shape or a strip shape can be used.

  Next, an aspect of electrical connection between an internal electrode and an external electrode forming a pair of ultraviolet ray generation sources will be described. The internal electrode is a portion having the same potential as the electrode inserted through the side of the arc tube where the ultraviolet ray generation source is arranged, that is, one of the small-diameter cylindrical portions, for example, the internal introduction line of the external tube or the current introduction connected thereto. Connect to conductor. The external electrode is connected to a portion having the same potential as the electrode inserted into the other small-diameter cylindrical portion of the arc tube, preferably a support member.

  In addition, by making a part of the external electrode close to a portion where a space communicating with the surrounding portion is formed in one small-diameter cylindrical portion of the arc tube, the potential gradient of the internal space of the small-diameter cylindrical portion is increased. Increases the start acceleration action. For this reason, an external electrode can be used as a proximity conductor for the arc tube. If the proximity part of the external electrode to the small-diameter cylindrical part is an intermediate part between the surrounding part of the ultraviolet ray generation source and the part connected to the same potential part as that of the other electrode, the arrangement and shaping of the external electrode can be performed. It becomes easy and preferable. Moreover, as a mode of proximity to the small-diameter cylindrical portion, a mode in which a close position extends in a straight line, a mode in which a coil shape of one to a plurality of turns is adjacent may be used.

  [Operation of the present invention] In the present invention, since the high-pressure discharge lamp has the above-described configuration, at the time of starting the high-pressure discharge lamp, a starting voltage is applied between the pair of electrodes of the arc tube. A starting voltage is also applied between the internal electrode and the external electrode of the ultraviolet ray generation source.

  At substantially the same time as the starting voltage is applied, the ultraviolet radioactive gas inside the small vessel of the ultraviolet ray generation source is excited to cause discharge, and the generated ultraviolet ray is emitted from the small vessel to the outside. And since a part of the emitted ultraviolet rays irradiates the arc tube, the starting gas inside the arc tube is excited by the ultraviolet irradiation, so the starting voltage of the high-pressure discharge lamp decreases, and it starts easily and lights up. To start.

  According to the present invention, the ultraviolet ray generation source is disposed between the inner surface of the outer tube and one of the small-diameter cylindrical portions of the arc tube at a position generally facing the support member in the substantially cylindrical outer tube. As a result, even if a small outer tube is used, the arc tube, the support member, and the ultraviolet ray generation source can be functionally accommodated in the outer tube, and the ultraviolet ray generation source is disposed on the side of the small diameter cylindrical portion. It is possible to irradiate ultraviolet rays at a short distance to a portion that is effective for assisting starting of the tube portion. As a result, not only the starting voltage is lowered, but also a compact high-pressure discharge lamp can be provided.

  In addition, if the external electrode of the ultraviolet ray generation source is brought close to the portion effective for starting assistance of the small diameter cylindrical portion, the external electrode can also act as a proximity conductor, and as a result, multiple starting assistance is performed. Further, the starting voltage is further lowered.

  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 of the present invention, FIG. 1 is a front view, and FIG. 2 is an enlarged sectional view of an arc tube. The high-pressure discharge lamp of this embodiment has a structure suitable for a rated lamp power of 70 W, and includes an outer tube OT, an arc tube IT, a support member SF, an ultraviolet ray generation source UVE, and a getter G.

  The outer tube OT is a T-shaped bulb having a substantially cylindrical shape made of ultraviolet cut quartz glass and has a maximum outer diameter of 16 mm or less. An exhaust tip off portion 11 is formed at the center of the closed tip. A pinch seal portion 12 is formed at the proximal end. In each pinch seal portion 12, a pair of sealing metal foils 12a, 12a, internal lead wires 12b, 12c and external lead wires 12d, 12d are arranged in a relationship as shown in FIG.

  As shown in FIG. 2, the arc tube IT includes a translucent ceramic hermetic container 1, a pair of electrodes 2, 2, a pair of current introduction conductors 3, 3, a pair of seal portions 4, 4, and a translucent ceramic hermetic container. 1 has a discharge medium sealed inside.

  The translucent ceramic hermetic container 1 is made of translucent alumina ceramics, and includes a surrounding portion 1a and a pair of small-diameter cylindrical portions 1b1, 1b2 disposed in communication with both ends of the surrounding portion 1a, and a discharge space 1c therein. Is formed. The surrounding portion 1a and the small diameter cylindrical portions 1b1, 1b2 are integrated by casting.

  The pair of electrodes 2 and 2 is made of a tungsten rod and is inserted into the small diameter cylindrical portions 1b1 and 1b2. A slight gap is formed between the shaft portion of the electrode 2 and the inner surfaces of the small diameter cylindrical portions 1b1 and 1b2. The tip of the electrode 2 protrudes into the surrounding part 1a.

  As shown in FIG. 2, the pair of current introduction conductors 3 and 3 are each composed of a single body such as niobium or cermet or a composite body in which both members are joined in the longitudinal direction. And the front-end | tip is inserted in small diameter cylinder part 1b1, 1b2, is connected to the base end of the electrode 2, supports the electrode 2, and the base end protrudes outside from the small diameter cylinder part 1b1, 1b2. The base end of the current introduction conductor 3 on the upper side in FIG. 1 derived from the small-diameter cylindrical portion 1b2 is inserted into the exhaust tip-off portion 11 of the outer tube OT, so that a part of the support member SF described later is provided. It also contributes to the centering of the arc tube IT.

  The pair of seal portions 4 and 4 are formed by heating and melting a ceramic sealing compound and solidifying it. Then, the pair of seal portions 4, 4 includes the end surface side portions of the small diameter cylindrical portions 1 b 1, 1 b 2 of the translucent discharge vessel 1, the niobium rod-like bodies Nb of the current introduction conductors 3, 3 facing this, The light-transmitting ceramic discharge vessel 1 is hermetically sealed with a small diameter cylindrical portion 1b1, so that the pair of introduction conductors 3 and 3 are not exposed to the inside of the light-transmitting ceramic hermetic vessel 1. The entire portion inserted into 1b2 is covered.

  The discharge medium is made of a metal halide, a starting gas, and mercury, and is enclosed in the translucent discharge vessel 1. Note that the metal halide and mercury are encapsulated in excess of the amount that evaporates. A part of the metal halide stays in a liquid state in a slight gap formed in the small diameter cylindrical portions 1b and 1b during stable lighting. And the coldest part is formed in the surface layer part vicinity of the discharge medium which stays in the liquid phase state, for example in the small diameter cylinder part 1b1 used as the lower side during lighting.

  The metal halide is made of a luminescent metal halide, and can be composed of a metal halide selected from the group of thulium (Tm), sodium (Na), thallium (Tl), and rare earth metals, for example.

  The support member SF is formed by integrally extending the internal lead-in wire 12b. Then, a position approaching the inner wall of the outer tube OT extends along the tube axis direction, the tip is bent near the tip of the outer tube OT, and is welded to the lead-in line 3 at the top of the arc tube IT in FIG. Thus, the arc tube IT is supported.

  The ultraviolet ray generation source UVE includes a small container 21, an introduction line 22, an internal electrode 23, a discharge gas, and an external electrode 24. The small vessel 21 has a bottomed cylindrical capsule shape with a maximum outer diameter of 4 mm or less made of ultraviolet transmissive quartz glass, and an elongated discharge space is formed inside. The lead-in wire 22 is made of molybdenum, and the tip is welded to the internal electrode 23. The internal electrode 23 is made of a strip-shaped molybdenum foil and is sealed in the discharge space of the small vessel 21. The discharge gas is made of argon, for example, and is enclosed in the small container 21. The external electrode 24 is made of a molybdenum wire, and its tip end is tightly wound around the outer periphery of the small container 21 and is wound several turns. The intermediate portion extends substantially linearly and is placed inside one small-diameter cylindrical portion 1b1. It approaches so that it may contact substantially the outer surface of the position which opposes the site | part in which slight space is formed, and the base end part is welded to support member SF.

  Further, the ultraviolet ray generation source UVE is located at a position facing the support member SF, and a main portion thereof is disposed between the inner surface of the outer tube OT and one small-diameter cylindrical portion 1b1 of the arc tube IT. As a result, the small-diameter cylindrical portion 1b1 and the ultraviolet ray generation source UVE are arranged substantially in parallel with each other along the tube axis direction.

  The getter G is welded to the support member SF and cleans the inside of the outer tube OT.

  In the high-pressure discharge lamp shown in FIG.

Outer tube: Maximum outer diameter 15mm
Arc tube translucent ceramics discharge vessel: made of translucent polycrystalline alumina ceramics,
Enclosure inner diameter 6mm, outer diameter 7.6mm, small diameter cylinder inner diameter 0.8mm, outer diameter 2.4mm,
36mm length
Ultraviolet light source: Maximum outer diameter of small container 3.25mm, length 1.5mm, discharge gas Ar,
Sealing pressure approx.2.7kPa
The external electrode is formed with 3 turns of 0.2 mm diameter Mo wire.

Hereinafter, another embodiment for carrying out the present invention will be described with reference to FIGS. 3, 6, and 7. In addition, in each figure, the same code | symbol is attached | subjected about the part same as FIG. 1, and description is abbreviate | omitted.

    FIG. 3 is a front view showing a second embodiment for carrying out the high-pressure discharge lamp of the present invention. In the high-pressure discharge lamp of this embodiment, the external electrode 24 of the ultraviolet ray generation source UVE is a ribbon-like Mo foil. Then, a one-turn coil is formed in which the distal end is in close contact with the outer peripheral surface of the small container 21, the intermediate portion is in contact with the same outer surface portion of the small-diameter cylindrical portion 1b1, and the proximal end is welded to the support member SF. ing. Other configurations are the same as those in the first embodiment shown in FIG.

  In the high-pressure discharge lamp shown in FIG.

  Ultraviolet light source: The external electrode is formed of a 0.3 mm thick and 2 mm wide Nb foil slightly shorter than one turn.

Other specifications are the same as those in the first embodiment.

Next, the results of manufacturing five high-pressure discharge lamps of Example 1 and Example 2 and investigating the starting voltage will be described. For lighting, an electronic ballast having a pulse voltage of about 3.5 kV and a secondary open-circuit voltage of 250 V or more was used. The discharge start voltage of the high pressure discharge lamp was observed with an oscilloscope. Further, the comparative example has the same specifications as in Example 1 except that it does not have an ultraviolet ray generation source. FIG. 4 shows the results of the starting voltage survey conducted at the start of the specification.

  As apparent from the table of FIG. 4, in the present invention, the starting voltage is significantly reduced as compared with the comparative example.

  Furthermore, the result of investigating the discharge start voltage when the test lamp is lit up to 6000 hours is shown in FIG.

  As is apparent from the table of FIG. 5, in the present invention, all the lamps can be started even after lighting for 6000 hours, but in the comparative example, two lamps are unsatisfactory.

    FIG. 6 is a front view showing a third embodiment for implementing the high-pressure discharge lamp of the present invention. This embodiment has the same configuration as that of the first embodiment except that an intermediate portion of the external electrode 24 of the ultraviolet ray generation source UVE is wound in a coil shape on the outer peripheral surface of the small diameter cylindrical portion.

    FIG. 7 is a front view showing a fourth mode for carrying out the high-pressure discharge lamp of the present invention. In this embodiment, the outer tube OT has a multiple tube structure. That is, the outer tube OT includes a first tube OT1 and a second tube OT2. The first tube OT1 has the same configuration as that of the first embodiment shown in FIG. The second tube OT2 is disposed outside the first tube OT1 and includes a screw cap B.

The front view which shows the 1st form for implementing the high pressure discharge lamp of this invention Similarly enlarged sectional view of arc tube The front view which shows the 2nd form for implementing the high pressure discharge lamp of this invention Table showing results of starting voltage investigation in Example 1 and Example 2 together with that of Comparative Example The table which shows the result of the starting voltage investigation in the same lighting 6000 hours The front view which shows the 3rd form for implementing the high pressure discharge lamp of this invention The front view which shows the 4th form for implementing the high pressure discharge lamp of this invention

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Translucent ceramics discharge container, 1a ... Enveloping part, 1b1, 1b2 ... Small diameter cylinder part, 1c ... Discharge space, 2 ... Electrode, 3 ... Current introduction conductor, 4 ... Seal part, 11 ... Exhaust chip | tip off part, 12 ... pinch seal part, 12a ... sealing metal foil, 12b, 12c ... internal lead wire, 12d ... external lead wire, 21 ... small container, 22 ... lead wire, 23 ... internal electrode, 24 ... external electrode, G ... getter, IT ... arc tube, OT ... outer tube, SF ... support member, UVE ... UV source

Claims (5)

A substantially cylindrical outer tube;
A translucent ceramic hermetic container having an enclosing portion surrounding the discharge space and a pair of small-diameter cylindrical portions communicating with both ends of the enclosing portion, and a pair of small-diameter cylindrical portions being inserted while forming a slight gap between the inner surface A pair of electrodes sealed in a light-transmitting ceramic hermetic container with their tips spaced apart from each other, a pair of current introduction conductors connected to the base end side of each electrode inside the pair of small diameter cylindrical portions, a small diameter cylindrical portion, and A pair of seal portions each sealing the translucent ceramic hermetic container between the current introduction conductors, and a discharge medium containing a metal halide and a starter gas sealed in the translucent ceramic hermetic container, are provided in the outer tube. An arc tube disposed;
A support member extending between the inner surface of the outer tube and the arc tube and supporting the arc tube;
Ultraviolet-permeable small container, dischargeable gas enclosed in a small container that emits ultraviolet light during discharge, and sealed inside the small container and connected to the same potential as one electrode of the arc tube An external electrode that surrounds the electrode and the small container and is connected to a portion that has the same potential as the other electrode of the arc tube, and that is substantially opposed to the support member and whose main part is the inner surface of the outer tube An ultraviolet light source disposed between one small-diameter cylindrical portion of the arc tube;
A high-pressure discharge lamp comprising: The outer tube has a maximum outer diameter of 16 mm or less;
The ultraviolet ray generation source has either a maximum outer diameter of the small container of 4 mm or less and 1/4 or less of the maximum outer diameter of the outer tube, and the length of the small container in the tube axis direction is 6 of the maximum outer diameter. 2. The high pressure discharge lamp according to claim 1, wherein the high pressure discharge lamp is less than double.   3. The ultraviolet ray generation source is arranged within a range of 180 ± 45 ° with respect to the arrangement position of the support member at an angle with respect to the tube axis of the arc tube. High pressure discharge lamp.   2. The ultraviolet ray generation source is characterized in that an external electrode thereof is further close to an outer surface of a portion where a space communicating with the enclosure portion is formed in the other small diameter cylindrical portion of the translucent ceramic hermetic container. 4. The high-pressure discharge lamp according to any one of items 3 to 3.   The high-pressure discharge lamp according to any one of claims 1 to 4, wherein the ultraviolet ray generation source has an external electrode surrounding surface of a small container having about 1 to 5 turns.

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