JP2006164709A - High pressure discharge lamp and high pressure discharge lamp lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high pressure discharge lamp in which generation of noises in an audible range, especially in a frequency of 900 Hz-4 kHz, generated at the time of lighting by rectangular wave current is suppressed, and a high pressure discharge lamp lighting device equipped with this. <P>SOLUTION: The high pressure discharge lamp is equipped with an arc tube IT having a fire-resistant translucent discharge container 1 with a discharge space 1c inside, a pair of electrodes 2, 2 which are sealed in the translucent discharge container 1 and face the discharge space 1c, and a discharge medium sealed in the translucent discharge container 1, a translucent outer tube OT which houses the arc tube IT inside, and an arc tube support member SF which supports the arc tube IT at a prescribed position in the outer tube OT with a part contacting the inner face of the outer tube OT and is constructed so that the lamp current may not flow, and the discharge lamp is energized by rectangular wave current. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a high-pressure discharge lamp energized by a rectangular wave current and a high-pressure discharge lamp lighting device including the same.

  Conventionally, in a high-pressure discharge lamp for general illumination, in order to support the arc tube at a predetermined position in the outer tube, the upper and lower portions of the arc tube are fixed to a frame-like support member made of stainless steel or the like. Thus, a part of the support member elastically contacts the inner surface of the outer tube, and at the same time, the support member is airtightly introduced into the outer tube from the flare glass that seals the neck portion of the outer tube, and protrudes to the inside. Welded to the internal lead-in. Further, the internal lead-in wire and the electrode are connected by welding a band-shaped conductor welded to the support member to the electrode located on the distal end side of the outer tube of the arc tube. With the above structure, the arc tube is held at a predetermined position in the outer tube by the outer tube and the inner lead wire so that it does not deviate from the predetermined position with respect to vibration and impact applied from the outside. Because of such an arc tube support structure, the lamp current that flows through the arc tube due to discharge flows through the support member (see, for example, Patent Document 1).

  By the way, it is known that a high-pressure discharge lamp such as a metal halide lamp is lit using an electronic lighting circuit that outputs a rectangular wave current (see Patent Document 2). By lighting the high-pressure discharge lamp using the electronic lighting circuit, it is easy to control the lamp power and the like. In the case of a metal halide lamp equipped with an airtight container made of translucent ceramics, the re-ignition voltage tends to increase, but it is said that the re-ignition voltage is reduced by lighting using the above-described electronic lighting circuit. There are also advantages.

On the other hand, a metal halide lamp in which a halide of sodium (Na) as a luminescent metal is enclosed in an arc tube emits warm white visible light with high efficiency, but sodium has a small ionic radius, so positively charged sodium The ions are attracted by the potential due to the negative photoelectrons on the outer surface of the arc tube, pass through the arc tube bulb, and disappear from the arc tube, resulting in a decrease in luminous efficiency and a short life. In order to solve this problem, there is known a metal halide lamp that employs a structure in which no potential is applied to the support member, and therefore no lamp current flows through the support member (see Patent Document 3).
JP 2004-055319 A Japanese Patent Application Laid-Open No. 07-296778 Japanese Patent Laid-Open No. 2003-1000025

  However, when a high-pressure discharge lamp is lit using an electronic lighting circuit that outputs a rectangular wave current, there is a problem that noise in the audible frequency region is generated from the lamp. Since this noise includes a frequency band of 900 Hz to 5 kHz that is particularly unpleasant for humans, it is required to be reduced.

  As a result of an investigation by the present inventor, there is a support member when a magnetic field generated mainly by a rectangular wave lamp current flowing through the arc tube support member undergoes a sudden change at the rise and fall of the rectangular wave current. It was found that resonance occurred at a specific frequency, and the generated resonance sound propagated to the outer tube to generate noise. The present invention has been made based on this finding.

  An object of the present invention is to provide a high-pressure discharge lamp that suppresses generation of noise in an audible region, particularly a frequency of 900 Hz to 4 kHz, which is generated when the lamp is lit by a rectangular wave current, and a high-pressure discharge lamp lighting device including the high-pressure discharge lamp. .

    The high-pressure discharge lamp of the invention according to claim 1 is enclosed in a translucent discharge vessel having a discharge space therein, a pair of electrodes sealed in the translucent discharge vessel and facing the discharge space, and the translucent discharge vessel. An arc tube provided with a discharge medium; a translucent outer tube containing the arc tube; and a portion of the arc tube in contact with the inner surface of the outer tube to support the arc tube at a predetermined position in the outer tube And an arc tube support member configured to prevent the lamp current from flowing, and is energized by a rectangular wave current.

  [About the arc tube] In the present invention, the arc tube includes at least a translucent discharge vessel, a pair of electrodes, and a discharge medium.

    (Translucent discharge vessel) The translucent discharge vessel is translucent and has a discharge space inside. 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 translucent discharge container should just have a grade which functions without a problem as a translucent discharge container in the normal operation state of a high pressure discharge lamp. As a constituent material of the translucent discharge vessel, for example, quartz glass and translucent ceramics can be used. Examples of the translucent ceramics include single-crystal metal oxides such as sapphire, and polycrystalline metal oxides such as translucent airtight aluminum oxide, yttrium-aluminum-garnet (YAG), and yttrium oxide (YOX). And a polycrystalline non-oxide such as aluminum nitride (AlN). The inner volume of the translucent discharge 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.

  In addition, in order to supply current to the pair of electrodes, an introduction conductor connected to the electrodes can be led out from the translucent discharge vessel. As the introduction conductor, molybdenum is suitable when the translucent discharge vessel is made of quartz glass. In the case of a translucent alumina ceramic, niobium (Nb) or tantalum (Ta) is preferable.

    (Regarding the discharge medium) The discharge medium may be a medium in which a required discharge occurs between a pair of electrodes in the discharge space of the translucent discharge vessel. In the present invention, specific substance names are particularly limited. Is not to be done. For example, in the case of a metal halide lamp, it is composed of a light emitting metal halide, a lamp voltage forming substance, and a rare gas. The lamp voltage forming substance is a substance that is effective for making a voltage drop generated between a pair of electrodes during lamp operation, that is, a lamp voltage to a desired value, such as mercury or a metal halide having a relatively high vapor pressure. Consists of.

  In addition, the rare gas mainly acts as a starting gas and a buffer gas, but the specific kind of the rare gas is not limited. In the case of a metal halide lamp for general illumination, a mixed gas of neon (Ne) and argon (Ar) is preferable. The enclosure pressure of the rare 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.

  [Regarding the outer tube] The outer tube is disposed for the purpose of accommodating the arc tube therein, for example, keeping the arc tube warm, mechanically protecting it, or exhibiting a light diffusing action. The inside of the outer tube is generally kept airtight with respect to the atmosphere outside the lamp. The inside of the outer tube can be in a vacuum or an inert gas (for example, nitrogen or argon) atmosphere. Moreover, 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. If desired, the outer tube may be formed using translucent ceramics.

  In order to impart a light diffusing action to the outer tube, a light diffusing film such as a phosphor film or a silica film is conventionally formed on the inner surface of the outer tube as desired. In the present invention, in addition to providing a light diffusion type high-pressure discharge lamp by providing the light diffusion film, noise generated from an arc tube support member, which will be described later, is diffused by the light diffusion film due to rectangular wave lighting. It has also been found that the noise level is reduced due to absorption or the like.

  Further, the outer tube can adopt a shape such as a BT type valve or a T type valve. Therefore, the shape of the outer tube is not particularly limited. However, since the noise level tends to increase as the maximum diameter of the outer tube increases, the maximum diameter is preferably 120 mm or less. Further, if the maximum diameter is less than 30 mm, it becomes difficult to store the arc tube and the incidental structure inside. Therefore, the maximum diameter of the outer tube is preferably in the range of 30 to 120 mm.

  [About the arc tube support member] The arc tube support member is a means for assisting at least holding the arc tube in a predetermined position in the outer tube. For this purpose, a part of the arc tube support member is in contact with the inner surface of the outer tube, preferably elastic. Touch. For example, the outer tube can be brought into contact with the inner surface of the outer tube on the tip (top) side. The arc tube can be supported only by this contact.

  However, in order to support the arc tube more stably in addition to the arc tube support member as desired, a stem portion is provided on the proximal end portion (generally, the end portion to which the base is attached) of the outer tube as desired. Or an internal lead-in wire led out from the stem portion to the inside of the outer tube or a connecting wire welded to the internal lead-in wire. Further, for example, a configuration in which the introduction conductor connected to the electrode and the arc tube support member cooperate to support the arc tube is allowed. Accordingly, in each of the above-described modifications, the stem portion, the internal introduction line, the connection line, and the introduction conductor act as auxiliary support members that are not included in the arc tube support member.

  In addition, the arc tube 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 composed of a first support member that supports one end of the arc tube and a second support member that supports the other end.

  Further, the arc tube 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 mainly containing them, such as stainless steel. It can be formed using steel, Ni-Cu alloy, brass or the like. Therefore, the arc tube support member may be a ferromagnetic material, a paramagnetic material, or a diamagnetic material. Stainless steel also becomes a ferromagnetic material or a non-ferromagnetic material depending on the alloy ratio. Since stainless steel is a ferromagnetic material and a non-ferromagnetic material, the material can be obtained relatively easily and can be easily processed, and has excellent mechanical strength. It is practically suitable as a material for constituting.

  Furthermore, in the present invention, the arc tube support member is configured so that the lamp current does not substantially flow. For this purpose, for example, the lamp current flowing into the outer tube is supplied to the electrode of the arc tube without passing through the arc tube support member, for example, between the internal lead-in line and the lead conductor led out from the arc tube. They can be connected by a connection conductor arranged separately from the arc tube support member. In addition, it is preferable that the arc tube support member has an insulating relationship with a member that forms a flow path of a lamp current (for example, in the case of the above configuration, the internal lead-in wire, the connection conductor, and the lead-in conductor) If the lamp current does not substantially flow, even if it is connected in terms of potential as desired, it is allowed because it has a temporary effect.

  [Means for Energizing by Rectangular Wave Current] The high-pressure discharge lamp of the present invention is energized by the rectangular wave current and lights up. The rectangular wave current is generally easily obtained by using an electronic lighting circuit, and is most generally an alternating current having a substantially square waveform on the positive / negative polarity side. It is assumed that a half wave whose rising from 0 potential is slightly inclined within a range in which the re-ignition voltage can be suppressed includes a substantially trapezoidal current waveform. Further, the upper limit value of the current is not limited to a constant waveform, and the instantaneous value of the current during the half-wave cycle increases or decreases continuously or stepwise as long as it does not depart from the spirit of the invention. It may be a current waveform. The electronic lighting circuit is allowed to be known. For example, a circuit configuration mainly composed of a DC-AC conversion circuit such as a full-bridge inverter can be adopted.

  [Operation of the Invention] In the present invention, since the high-pressure discharge lamp has the above-described configuration, the lamp is attached to the arc tube support member that supports the arc tube at a predetermined position in the outer tube while the high-pressure discharge lamp is lit. Since the current does not substantially flow, a magnetic field is not generated in the arc tube support member. For this reason, as described in the section of the problem to be solved by the invention, noise generated by the arc tube support member resonating with a magnetic field is remarkably suppressed, and the noise level is lowered.

  [Other Configurations] Although not an essential component of the present invention, the following configurations can be appropriately added as desired.

  1. (About the middle tube) The middle tube includes a so-called shroud, which is a translucent member that surrounds the periphery of the arc tube in the outer tube at least in the direction perpendicular to the tube axis, and supports the arc tube. The member is supported together with the arc tube. For example, it is possible to keep the arc tube warm or to prevent the arc tube from scattering when the arc tube bursts.

  2. (About the base) The base is generally a power receiving terminal structure for supplying a rectangular wave current from the lighting circuit to the internal lead wire that is attached to the base end side of the outer tube and protrudes airtightly from the stem portion into the outer tube. And a means for mechanically supporting the high-pressure discharge lamp through the lamp socket. Note that since the base is made of a non-ferromagnetic material, the noise level tends to be lower than when the base is made of a ferromagnetic material.

    A high pressure discharge lamp according to a second aspect of the present invention includes a fire-resistant translucent discharge vessel having a discharge space therein, a pair of electrodes sealed in the translucent discharge vessel and facing the discharge space, and the translucent discharge vessel An arc tube having a discharge medium sealed in; a translucent outer tube containing the arc tube inside; in a direction perpendicular to the tube axis interposed between the arc tube and the outer tube An inner tube that surrounds the arc tube and is housed in the outer tube; and a part of the inner tube contacts the inner surface of the outer tube to support the arc tube and the inner tube at a predetermined position in the outer tube and prevent a lamp current from flowing. And an arc tube support member configured to be energized by a rectangular wave current.

  The present invention is different from the invention according to claim 1 in that the arc tube support member is configured to support both the arc tube and the middle tube. Therefore, the middle tube is always held in a predetermined positional relationship with the arc tube by the arc tube support member. In addition, the arc tube can be configured to be supported by the arc tube support member via the middle tube.

    A high pressure discharge lamp according to a third aspect of the present invention is the high pressure discharge lamp according to the first or second aspect, wherein the arc tube support member is made of a non-ferromagnetic material.

  As the non-ferromagnetic material, for example, a metal such as copper (Cu) and aluminum (Al) or an alloy such as Ni—Cu alloy and brass can be used.

  In the present invention, since the arc tube support member is made of a non-ferromagnetic material, even if a magnetic field is generated in the lamp by the lamp current during lighting, the arc tube support member is less likely to resonate due to the influence of the magnetic field. For this reason, generation of noise due to resonance is further suppressed.

    A high pressure discharge lamp according to a fourth aspect of the present invention is the high pressure discharge lamp according to any one of the first to third aspects, wherein the outer tube has a light diffusion film having a total light transmittance of 40% or more on the inner surface thereof. It is characterized by that. The present invention defines a preferable configuration of a high-pressure discharge lamp that is a light diffusion type and has a noise reduction effect by a light diffusion film. In addition, the range of the preferable total light transmittance which is further excellent in the light diffusion and noise reduction effect is 60% or more.

The light diffusion film has a total light transmittance of 60% or more in order to make the high-pressure discharge lamp into a light diffusion type. Further, the light diffusion film can be composed of, for example, a phosphor film or a silica film. In addition, although the kind of fluorescent substance is not specifically limited for a fluorescent substance film, For example, the fluorescent substance of 3 wavelength light emission type can be used. And it is excited by the ultraviolet rays which permeate | transmit an arc tube, and the visible light of red, green, and blue is generated, and each luminescent color is additively mixed and turns into white light. In the case of a silica film, it is allowed to add several mass% of light diffusing particles such as alumina (Al ₂ O ₃ ) and titania (TiO ₂ ) to the main component silica (SiO ₂ ) as desired. The linear transmittance of the glass forming the outer tube is about 65%.

    A high-pressure discharge lamp according to a fifth aspect of the present invention is the high-pressure discharge lamp according to the fourth aspect, wherein the light diffusion film has a light diffusion of an average particle size of 1.0 to 3.0 μm and a particle size distribution of 3.0 to 6.0 μm. It is characterized by being formed using a conductive powder. The present invention defines the average particle size and particle size distribution of a light diffusing powder that can easily form a light diffusing film. In addition, the preferable range of a light-diffusion film is an average particle diameter of 2.0-2.6 micrometers, and a particle size distribution of 4.0-5.0 micrometers.

  Thus, the light diffusing film formed on the inner surface of the outer tube using the above light diffusing powder has moderate irregularities formed on the surface, so that noise is easily diffused and absorbed. .

    A high-pressure discharge lamp according to a sixth aspect of the present invention is the high-pressure discharge lamp according to any one of the first to fifth aspects, wherein the translucent discharge vessel is made of translucent ceramics. The present invention defines the configuration of a high-pressure discharge lamp to which the noise reduction effect contributes effectively.

  That is, although the reason for the noise generated when lighting with a rectangular wave current is not clear, the material of the translucent discharge vessel of the arc tube tends to be slightly higher than that of quartz glass in general than translucent ceramics. It can be seen. The noise level varies depending on the size and structure of the translucent discharge vessel made of translucent ceramics, but is about several dB higher than that made of quartz glass.

  However, according to each invention demonstrated above, even if it is a case where the translucent discharge vessel made from translucent ceramics is provided, a noise is reduced effectively.

    A high-pressure discharge lamp according to a seventh aspect of the invention is characterized in that in the high-pressure discharge lamp according to any one of the first to sixth aspects, the lamp is lit at a lamp current of 1.5 A or more. The present invention defines a lamp current that is likely to generate noise when lit by a rectangular wave current, and thus a lamp current range in which noise reduction according to the present invention contributes effectively. The lamp current generally means a rated lamp current, but is not necessarily limited to the rated lamp current.

  The high-pressure discharge lamp defined in claims 1 to 7 described above has a particularly significant contribution to noise reduction when the lamp power is 250 W or more. In addition, although the said lamp electric power generally means rated lamp electric power, it is not necessarily limited to this.

    According to an eighth aspect of the present invention, there is provided a high pressure discharge lamp lighting device comprising: the high pressure discharge lamp according to any one of the first to seventh aspects; and a lighting circuit that outputs a rectangular wave current to energize the high pressure discharge lamp. It is characterized by that.

  In the present invention, the lighting circuit may have any circuit configuration as long as it can output a rectangular wave current and supply it to the high pressure discharge lamp. However, an electronic lighting circuit is suitable, and the electronic lighting circuit can be mainly composed of a DC-AC conversion circuit such as a full-bridge inverter or a half-bridge inverter. Also, the rising and falling of the rectangular wave current may be configured such that the waveform changes not only perpendicularly to the time axis but also slightly inclined.

  Further, when the lighting circuit is mainly composed of a DC-AC conversion circuit, in order to eliminate a voltage mismatch between the DC power supply and the DC-AC conversion circuit, or to control a rectangular wave current output, etc. For this purpose, a DC-DC converter circuit such as a chopper circuit can be interposed between the DC power supply and the DC-AC converter circuit.

  Furthermore, a starting device such as an igniter can be provided in addition to the lighting circuit. In the case of an igniter, a high voltage pulse is generated at the start of the high pressure discharge lamp and applied between the pair of electrodes of the high pressure discharge lamp, thereby starting the high pressure discharge lamp.

  According to each of the first to seventh aspects of the present invention, it is possible to provide a high pressure discharge lamp that suppresses the generation of noise having an audible region, particularly a frequency of 900 Hz to 4 kHz, which is generated when the lamp is lit by a rectangular wave current.

  According to invention of Claim 6, the high pressure discharge lamp lighting device which has the effect of Claims 1 thru | or 7 can be provided.

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

    1 and 2 show a metal halide lamp as a first embodiment for carrying out the high-pressure discharge lamp of the present invention. FIG. 1 is a partially cutaway view showing a main part by breaking a part of an outer tube. FIG. 2 is an enlarged sectional view of the arc tube. The metal halide lamp of this embodiment has a structure suitable for a rated lamp power of 400 W. As shown in FIG. 1, the arc tube IT, outer tube OT, middle tube SG, arc tube support member SF, UV enhancer UVE, getter G And a base B. The rated lamp current is 4.0A.

  As shown in FIG. 2, the arc tube IT includes a translucent discharge vessel 1, a pair of electrodes 2, 2, a pair of introduction conductors 3 </ b> A, 3 </ b> B, a pair of seal portions 4, 4, and the translucent discharge vessel 1. A discharge medium sealed in the container.

  The translucent discharge vessel 1 is made of translucent alumina ceramics, and includes a surrounding portion 1a and a pair of small-diameter cylindrical portions 1b and 1b disposed in communication with both ends of the surrounding portion 1a, and a discharge space 1c is provided therein. Have. And the surrounding part 1a and the small diameter cylinder parts 1b and 1b are integrated by casting, and the full length is about 80 mm.

  The encircling portion 1a is a substantially bowl shape in which two spheres are separated in the axial direction so as to partially overlap each other to form hemispherical portions at both ends, and the hemispherical portions are connected by a straight line. The outer diameter is about 22 mm, the inner diameter is 20 mm, the wall thickness is 1.0 mm, and the inner volume is about 4.0 cc.

  The pair of small-diameter cylindrical portions 1b and 1b each have a pipe shape with an outer diameter of about 3.5 mm and an inner diameter of about 1.6 mm, and the tip is connected to the central portion of the hemispherical portion of the surrounding portion 1a. In addition, as for the boundary part of the surrounding part 1a and a pair of small diameter cylinder parts 1b and 1b, the inner and outer both surfaces are formed by the curved surface.

  The pair of electrodes 2 and 2 includes an electrode shaft 2a and an electrode main portion 2b. The electrode shaft 2a is made of a tungsten rod having an outer diameter of 0.9 mm and a length of about 8 mm, and is inserted into the small-diameter cylindrical portions 1b and 1b. A slight gap is formed between the electrode shaft 2a and the inner surfaces of the small diameter cylindrical portions 1b and 1b. The electrode main part 2b is formed by winding a tungsten fine wire having an outer diameter of 0.3 mm around the tip of the electrode shaft 1a at a dense pitch of about 5 turns, and projects into the surrounding part 1a. The distance between the electrodes is about 20 mm.

  As shown in FIG. 2, the pair of lead conductors 3A and 3B are each composed of a niobium rod-shaped body Nb and a cermet rod-shaped body SM. The niobium rod-like body Nb has an outer diameter of about 1.0 mm and a length of about 15 mm, the cermet rod-like body SM is made of a molybdenum-alumina sintered body, the outer diameter is about 1.4 mm, and the length is about 18 mm. The both rod-like bodies Nb and SM are integrally formed by welding in a straight line. The niobium rod-like body Nb has a distal end inserted into the small diameter cylindrical portions 1b and 1b, and a base end protruding outward from the small diameter cylindrical portions 1b and 1b.

Each of the pair of seal portions 4 and 4 is formed by heating and melting and solidifying a ceramic sealing compound made of Dy ₂ O ₃ —SiO ₂ —Al ₂ O ₃ . Thus, the pair of seal portions 4, 4 includes a portion on the end face side of the small-diameter cylindrical portions 1 b, 1 b of the translucent discharge vessel 1, and the niobium rod-shaped body Nb of the introduction conductors 3, 3 facing this. The translucent ceramics discharge vessel 1 is hermetically sealed with an intervening space therebetween, and a so-called introduction conductor insertion sealing structure is provided. The entire portion inserted into the small-diameter cylindrical portions 1b and 1b is covered so as not to be exposed. With the above sealing, the electrodes 2 and 2 are fixed at predetermined positions of the translucent discharge vessel 1.

  In order to form the seal portion 4, the translucent discharge vessel 1 is set in a vertical position, and a ring frit glass (not shown) of a ceramic sealing compound is positioned on the upper side and sealed at that time. For example, it is placed on the end surface of the small-diameter cylindrical portion 1b to be stopped, and the ring-shaped pellet is heated and melted to enter the gap between the introduction conductor 3A and the small-diameter cylindrical portion 1b, and the small-diameter cylindrical portion 12a. The entire niobium rod-like body Nb of the introduction conductor 3A constituting the portion inserted into the inside is covered. Next, the translucent discharge vessel 1 is inverted 180 °, and the seal portion 4 is formed on the other small-diameter cylindrical portion 1b side in the same manner as described above.

  The discharge medium is composed of argon as a starting gas and a buffer gas, the following metal halide, and mercury as a buffer vapor, and is enclosed in the translucent discharge vessel 1. Since metal halide and mercury are encapsulated in excess of the amount that evaporates, some of them stay in a liquid phase state in a slight gap formed in the small diameter cylindrical portions 1b and 1b during stable lighting. ing. 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 1b used as the lower side during lighting.

  The metal halide comprises a luminescent metal halide, for example a metal halide selected from the group of thulium (Tm) halide, sodium (Na) halide, thallium (Tl) halide and rare earth metal halide. Can be configured.

  The outer tube OT uses a BT bulb made of hard glass and has a maximum diameter portion of an outer diameter of about 116 mm, a maximum inner diameter of about 114 mm, a wall thickness of about 1.0 mm, and a total length of about 300 mm. Then, members such as the arc tube IT, the middle tube SG, and the arc tube support member SF are accommodated therein. Further, the outer tube OT is provided with a flare stem 5 sealed at a neck portion located at the lower portion in FIG. The flare stem 5 introduces a pair of internal lead-in wires 6A and 6B in an airtight manner into the outer tube OT. The lower introduction conductor 3A in FIG. 1 of the arc tube IT is connected to the internal introduction line 6A via the connection conductor 7. The introduction conductor 3B at the top of the arc tube IT is connected to the internal introduction line 6B via the curved conductor 8. Thereby, the pair of electrodes 2 and 2 of the arc tube IT are connected between the internal lead-in wires 6A and 6B via the connecting conductor 7 and the curved conductor 8. The curved conductor 8 is curved along the inner surface of the outer tube OT in a direction away from the arc tube IT. Thus, the arc tube IT is mainly supported in the tube axis direction mainly by the connection conductor 7 and supplementarily by the curved conductor 8.

  The middle tube SG is formed of a cylindrical quartz glass body having a thickness of 1.0 mm, and is disposed by a light emitting tube support member SF described later at a position surrounding the light emitting tube IT in a direction perpendicular to the tube axis in the outer tube OT. Is retained.

  The arc tube support member SF includes a support frame 11, a stem fitting plate 12, a pair of support plates 13 and 14, and a spring piece 15. The support frame 11 is formed by bending a stainless steel rod into a gate shape. The stem fitting plate 12 is formed of a stainless steel plate in a disc shape, and is fitted and locked to the head of the flare stem 5. Then, both legs of the support frame 11 are fixed. Thus, the lower end of the support frame 11 is supported by the stem fitting plate 12 in FIG. The pair of support plates 13 and 14 are formed of a stainless steel plate in a substantially disk shape, and are supported by using the locking claws 13a and 14a formed at the upper and lower ends of the intermediate tube SG, and the mounting claws 13b. 14b are fixed to the support frame 11. In addition, a through hole is formed in the central portion of the pair of support plates 13 and 14, and the arc tube IT is formed by inserting the pair of small diameter cylindrical portions 1b and 1b of the translucent discharge vessel 1 into the through hole. Is placed at the tube axis position of the outer tube OT, and the arc tube IT is mainly supported in a direction perpendicular to the tube axis. The spring piece 15 is divided and welded to the left and right at the upper part in FIG. 1 of the support frame 11 and elastically contacts the inner surface of the head of the outer tube OT, so that the upper part of the support frame 11 is attached to the head of the outer tube OT. Elastically supports the inner surface of the part.

  As is clear from the above, the arc tube support member SF mechanically supports the arc tube IT and the middle tube SG at a predetermined position with respect to the outer tube OT. Not connected to IT. The arc tube IT is supported by the arc tube support member SF mainly in a direction orthogonal to the tube axis.

  Since the UV enhancer UVE is known in principle, the detailed structure is not shown in the figure, but is configured to include an airtight container, an introduction line, an internal electrode, a discharge medium, and an external electrode. The hermetic container is made of ultraviolet transmissive glass such as quartz glass, and has an elongated discharge space formed therein. The lead-in wire is made of molybdenum, the tip is welded to an internal electrode to be described later, and the base end is welded to the curved conductor 8 as shown in FIG. 1, so that the lead wire is connected to the internal lead-in wire 6B via the curved conductor 8. Yes. The internal electrode is made of molybdenum and has a plate shape, and is sealed in the discharge space of the hermetic vessel. The discharge medium is composed of about 1.3 kPa of argon and is enclosed in an airtight container. The external electrode is made of a molybdenum wire having an outer diameter of 0.4 mm, is tightly wound on the outer periphery of the airtight container and is wound about 5 turns, and is connected to the connection conductor 7 via the conductor 16. As is clear from the above, the UV enhancer UVE is connected in parallel to the arc tube IT.

  Then, when the high-pressure discharge lamp is connected to a lighting circuit that outputs a rectangular wave current and is operated, the rectangular wave of the lighting circuit is connected between the pair of internal lead-in wires 6A and 6B via the base B. When the no-load output voltage is applied, first, discharge occurs between the internal electrode and the external electrode of the UV enhancer UVE. As a result, the discharge medium in the translucent discharge vessel generates ultraviolet light. The ultraviolet light passes through the translucent discharge vessel and is emitted into the outer tube OT. Since this ultraviolet light irradiates the arc tube IT, the electrode 2 inside the arc tube IT is excited, so that photoelectrons are emitted, resulting in a discharge between the pair of electrodes 2 and 2 in the arc tube IT. It is easy to occur, and the start of the high pressure discharge lamp is promoted. Note that the ultraviolet light emitted from the UV enhancer UVE is substantially blocked by the outer tube OT, and therefore hardly affects the outside of the high-pressure discharge lamp.

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

  The base 3 is an E39-type base, which is fixed to the neck portion of the outer tube 5, and one of a pair of external lead wires (not shown) exposed to the outside from the outer tube OT is connected to the shell portion and the other is connected to the center contact. is doing. The pair of external lead wires are connected to the internal lead wires 6A and 6B via the flare stem 5 in an airtight manner.

  Next, the noise level at the time of lighting by the rectangular wave current in the high-pressure discharge lamp of the present invention will be described with reference to FIG. 3 and FIG. 4 while comparing with that of the comparative example. The comparative example has the structure shown in FIG. 7, and the same parts as those in FIG. The comparative example is a conventional structure of a high-pressure discharge lamp that is lit by a rectangular wave current. In the figure of the arc tube support member SF, the lower part is welded to the internal lead-in wire 6B, and the arc tube support member SF is the upper band conductor 17. The upper introduction conductor 3B is connected to the band-shaped conductor 17 in the figure of the arc tube IT. For this reason, the lamp current is supplied between the pair of electrodes of the arc tube IT via the arc tube support member SF.

    FIG. 3 is a table showing the results of measuring the noise level during lighting for each of the 10 high-pressure discharge lamps of the present invention shown in FIG. 1 and the comparative example shown in FIG. In the table, the conventional structure shows a comparative example, and the structure of the present invention shows the high-pressure discharge lamp of the present invention. The frequency of the rectangular wave current is 200 Hz. The high-pressure discharge lamp was turned on in the lighting fixture, and the noise was measured at a distance of 50 cm directly under the lamp. The high-pressure discharge lamp used has a rated lamp power of 400 W, and the outer tube is a BT116 type bulb.

  As is apparent from FIG. 3, in the case of the present invention, it can be seen that the noise level is significantly reduced as compared with the comparative example.

    FIG. 4 is a graph showing the noise level when the maximum diameter of the outer tube OT is changed in the high-pressure discharge lamp of the present invention shown in FIG. 1 and the comparative example shown in FIG. In the figure, the horizontal axis indicates the maximum diameter (mm) of the outer tube, and the vertical axis indicates the lighting in the apparatus as in FIG. 3, and the noise level (dB) immediately below 50 cm. In the figure, symbol ◆ indicates the noise level of the comparative example, and symbol ■ indicates the noise level of the present invention. In addition, the magnitude | size of the width shown above and below each said symbol has shown the distribution range of the measured value.

  As can be understood from FIG. 4, according to the present invention, the noise level is lower than that of the comparative example regardless of the maximum diameter of the outer tube. In both the present invention and the comparative example, the noise level tends to increase as the maximum diameter of the outer tube increases.

  Next, a metal halide lamp as a second embodiment for implementing the high-pressure discharge lamp of the present invention will be described. Although not shown, this embodiment differs from the first embodiment for carrying out the present invention shown in FIGS. 1 and 2 in that a light diffusion film is formed on the inner surface of the outer tube OT.

  The light diffusion film is made of a phosphor film, and is formed on the remaining portion excluding the neck portion of the outer tube OT. In addition, the average particle diameter of the used fluorescent substance is 2.0-2.6 micrometers, and a particle size distribution is 4.0-5.0 micrometers.

  In order to compare the noise levels in the first and second embodiments of the present invention, the high pressure discharge lamp in the first embodiment having a transparent outer tube bulb in the outer tube OT, and a diffusion type in which a light diffusion film is formed on the inner surface. FIG. 5 shows a table showing the results of making five prototypes of high pressure discharge lamps according to the second embodiment having outer bulbs and measuring their noise levels. Note that, as is clear from the above, both the high-pressure discharge lamps have the same specifications except that the specifications of their outer tubes are different.

  As can be understood from FIG. 5, the noise of about 2.5 dB is reduced by providing the diffusion type outer tube valve as compared with the case having the transparent outer tube valve.

    FIG. 6 is a circuit diagram showing an embodiment of the high pressure discharge lamp lighting device of the present invention. In the figure, 21 is a DC power source, 22 is a DC-DC conversion circuit, 23 is a DC-AC conversion circuit, 24 is an igniter, and 25 is a high-pressure discharge lamp.

  The direct current power source 21 is a rectified direct current power source, and obtains direct current by rectifying a low frequency alternating current power source such as a commercial power source.

  The DC-DC conversion circuit 22 converts the DC voltage output from the DC power supply 21 into a different DC voltage. For example, it consists of a step-up DC chopper.

  The DC-AC conversion circuit 23 converts the DC voltage output from the DC-DC conversion circuit 22 into a rectangular wave low-frequency AC voltage. For example, it consists of a full bridge type inverter. Therefore, the high-pressure discharge lamp 25 is lit by a rectangular wave current.

  The igniter 24 generates a high voltage pulse when starting the high pressure discharge lamp 25 to start the high pressure discharge lamp 25.

  The high-pressure discharge lamp 25 is the high-pressure discharge lamp shown in FIG. 1, and is a rectangular wave current output from the DC-AC conversion circuit 23 and applied with a low-frequency AC voltage whose lighting frequency f satisfies 50 ≦ f ≦ 1000. Lights up.

The partially cutaway front view which shows the principal part by fracture | rupturing a part of outer tube | pipe about the metal halide lamp as one form for implementing the high pressure discharge lamp of this invention Similarly enlarged sectional view of arc tube A table showing the results of measuring the noise level during lighting for each of the 10 high-pressure discharge lamps of the present invention shown in FIG. 1 and the comparative example shown in FIG. A graph showing a noise level when the maximum diameter of the outer tube OT is changed in the high-pressure discharge lamp of the present invention shown in FIG. 1 and the comparative example shown in FIG. In the high-pressure discharge lamp of the present invention, the results of measuring the noise levels of five lamps with a transparent outer bulb and five lamps with a diffusion outer bulb having an inner surface formed with a light diffusion film were compared. Table The circuit diagram which shows one form of the high pressure discharge lamp lighting device of this invention Partially cutaway front view showing a main part of a comparative example having a conventional structure by cutting a part of the outer tube

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Translucent discharge vessel, 1b ... Small diameter cylindrical part, 1c ... Discharge space, 2 ... Electrode, 3A, 3B ... Introduction conductor, 5 ... Flare stem, 6A, 6B ... Internal introduction line, 7 ... Connection conductor, 8 ... Curved conductor, 11 ... support frame, 12 ... stem fitting plate, 13, 14 ... support plate, 15 ... spring piece, B ... base, IT ... arc tube, OT ... outer tube, SF ... arc tube support member, SG ... Middle tube, UVE ... UV enhancer

Claims (8)

A translucent discharge vessel having a discharge space therein, a pair of electrodes sealed in the translucent discharge vessel and facing the discharge space, and an arc tube including a discharge medium sealed in the translucent discharge vessel;
A translucent outer tube containing the arc tube inside;
An arc tube support member configured to support the arc tube at a predetermined position in the outer tube by partially contacting the inner surface of the outer tube and to prevent a lamp current from flowing;
A high-pressure discharge lamp characterized by being energized by a rectangular wave current. An arc tube comprising a fire-resistant translucent discharge vessel having a discharge space therein, a pair of electrodes sealed in the translucent discharge vessel and facing the discharge space, and a discharge medium sealed in the translucent discharge vessel; ;
A translucent outer tube containing the arc tube inside;
An intermediate tube interposed between the arc tube and the outer tube and surrounding the arc tube in a direction orthogonal to the tube axis and housed in the outer tube;
An arc tube support member configured so that a lamp current does not flow while supporting the arc tube and the middle tube at a predetermined position in the outer tube by partly contacting the inner surface of the outer tube;
A high-pressure discharge lamp characterized by being energized by a rectangular wave current. 3. The high pressure discharge lamp according to claim 1, wherein the arc tube support member is made of a non-ferromagnetic material. The high pressure discharge lamp according to any one of claims 1 to 3, wherein the outer tube includes a light diffusion film having a total light transmittance of 40% or more on an inner surface thereof. 5. The high pressure discharge lamp according to claim 4, wherein the light diffusion film is formed using a light diffusing powder having an average particle size of 1.0 to 3.0 [mu] m and a particle size distribution of 3.0 to 6.0 [mu] m. . 6. The high pressure discharge lamp according to claim 1, wherein the translucent discharge vessel is made of translucent ceramics. The high pressure discharge lamp according to any one of claims 1 to 6, wherein the high pressure discharge lamp is lit at a lamp current of 1.5A or more. A high-pressure discharge lamp according to any one of claims 1 to 7;
A lighting circuit that outputs a rectangular wave current to energize the high-pressure discharge lamp;
A high-pressure discharge lamp lighting device comprising:

Images