JP2013152851A - High-pressure discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly-reliable high-pressure discharge lamp capable of reducing cost of a manufacturing device and improving work efficiency in a manufacturing process to achieve reduction in cost of manufacture, and of preventing deterioration in air-tightness and maintaining the supporting and fixing firmly even when vibration or shock is added in a supported and fixed state.SOLUTION: A discharge electrode 30 is formed in a curved shape or a ripple shape. The discharge electrode 30 inserted into a discharge pipe 10 having end parts to which cylindrical metal pipes 20 are fused is pressure-welded to an inner wall of the discharge pipe 10. Thereby, in a manufacturing process, the discharge electrode 30 inserted into the discharge pipe 10 is in a state of being temporally fixed in the discharge pipe 10, and at commercialization, the metal pipe 20 serves as a supporting and fixing part, and simultaneously, serves as a power reception electrode for power supply from an external power source.

Description

  The present invention relates to a high-pressure discharge lamp, and more particularly, a high-pressure discharge in which a tip electrode portion formed at a tip portion of an electrode shaft is disposed in a discharge chamber of a light emitting portion and the electrode shaft is hermetically sealed. Regarding lamps.

  As an example of a conventional high-pressure discharge lamp 80, a configuration shown in FIG. 11 is disclosed. The discharge tube 81 is formed of substantially pipe-shaped translucent ceramics, and the metal pipe 83 is hermetically sealed at both ends of the discharge tube 81 via a compound 82 of a sealing adhesive. Then, an electrode 86 composed of the electrode shaft 84 and the tip electrode portion 85 formed at the tip of the electrode shaft 84 is inserted into the metal pipe 83, the end portion of the metal pipe 83 is narrowed down, and the narrowed diameter portion 87 is narrowed down. The electrode shaft 84 is melted and completely sealed.

  At this time, a metal halide or a sealed gas is sealed in the light emitting portion 88 formed by the discharge tube 81, the metal pipe 83, and the electrode 86. When the sealed gas is introduced into the light emitting portion 88, the metal pipe 83 is used. After forming the narrow-diameter portion 87, the sealed gas is introduced into the light-emitting portion 88 through the gap between the narrow-diameter portion 87 and the electrode shaft 84, and then the narrow-diameter portion 87 and the electrode shaft 84 are fused by a melting means such as a laser. The light emitting unit 88 is brought into a completely airtight state by hermetically sealing (see, for example, Patent Document 1).

JP 2007-220350 A

  By the way, as described above, in the high-pressure discharge lamp 80, the sealed gas is introduced into the light emitting portion 88 through the gap between the narrow diameter portion 87 of the metal pipe 83 and the electrode shaft 84 of the electrode 86. At that time, the electrode 86 needs to be held in a state supported by some support means (mechanism) provided outside the metal pipe 83.

  For this reason, it is required that the processing apparatus used in the gas processing process such as exhaust to the light emitting unit 88, replacement of rare gas, and introduction of sealed gas has a structure that takes into account the support mechanism of the electrode 86, and the structure becomes complicated. become. As a result, the price of the processing apparatus becomes expensive, which increases the manufacturing cost of the product (high pressure discharge lamp).

  In addition, when the hermetic sealing is performed by laser fusion bonding between the narrow diameter portion 87 of the metal pipe 83 and the electrode shaft 84 of the electrode 86, the electrode shaft 84 is on the central axis of the metal pipe 83, so Melt bonding by single-point laser beam irradiation is impossible, and melt bonding is performed by laser beam irradiation from the entire circumferential direction avoiding the electrode shaft 84. Therefore, the work efficiency of laser fusion bonding is not good, leading to an increase in manufacturing cost.

  Further, both the metal pipe 83 and the electrode 86 are formed of a refractory metal such as tantalum, tungsten, and molybdenum. Among them, for example, molybdenum is used as the refractory metal, and the metal pipe 83 and the electrode 86 are formed by the molybdenum. If formed, heating exceeding the melting point of molybdenum of 2620 ° C. is required at the time of fusion bonding of the narrow diameter portion 87 of the metal pipe 83 and the electrode shaft 84 of the electrode 86. In that case, it is known that when molybdenum reaches a temperature of 900 ° C. or higher, recrystallization occurs, and crystal grains become coarse due to recrystallization, and ductility and brittleness are remarkably reduced.

  By the way, in the high pressure discharge lamp 80 having the above-described configuration, it is assumed that the electrode shaft 84 of the electrode 86 is used for supporting and fixing the high pressure discharge lamp 80. Therefore, when the high-pressure discharge lamp 80 is used particularly as a light source for a vehicular lamp, vibrations and impacts when the vehicle travels are caused between the electrode shaft 84 of the support fixing portion and the narrow diameter portion 87 of the metal pipe 83 and the electrode shaft 84. It is transmitted to the joint, and brittle fracture starting from the grain boundaries of the above-mentioned coarsened crystal grains of molybdenum occurs at the joint, thereby impairing the hermeticity of the discharge tube 81 or supporting and fixing the high-pressure discharge lamp 80. Such as deteriorating the reliability of the system.

  Therefore, the present invention was devised in view of the above problems, and the object of the present invention is to reduce the manufacturing cost by reducing the cost of the manufacturing apparatus and improving the work efficiency in the manufacturing process. Another object of the present invention is to provide a highly reliable high-pressure discharge lamp capable of maintaining support and fixation firmly without impairing hermeticity even when vibration or impact is applied in the support and fixation state.

  In order to solve the above-mentioned problem, the invention described in claim 1 of the present invention has a thick tube portion and a thin tube portion having a diameter smaller than that of the large tube portion located on both sides of the thick tube portion, and the entire tube portion. A cylindrical discharge tube having a uniform wall thickness, a large diameter portion, and a small diameter portion smaller in diameter than the large diameter portion located on one side of the large diameter portion, and the discharge tube having the large diameter portion A cylindrical metal pipe having a uniform overall wall thickness, hermetically welded with the large diameter portion so as to cover both ends of the thin tube portion, a tip electrode portion having a predetermined length, and the tip Having an electrode shaft extending from one side of the electrode portion by a predetermined length, and the electrode shaft is integrally fused to the tip of the small diameter portion of the metal pipe and inserted through the narrow tube portion of the discharge tube A discharge electrode in which the tip electrode portion reaches the inside of the thick tube portion, and the discharge electrode is at least The electrode shaft has a shape curved in the longitudinal direction or a wave shape having two or more curved portions, and the electrode axis of the discharge electrode inserted through the narrow tube portion of the discharge tube is 2 of the inner wall of the narrow tube portion. It is characterized by being in pressure contact with more than a part.

  Further, in the invention described in claim 2 of the present invention, in claim 1, when the diameter of the electrode shaft of the discharge electrode is D0, the inner diameter of the small diameter portion of the metal pipe is D1, and the outer diameter is D2, It satisfies the relationship of 0 <(D1-D0) / (D2-D1) ≦ 0.6.

  In the high-pressure discharge lamp of the present invention, the discharge electrode is formed in a curved shape or a wave shape, and the discharge electrode inserted into the discharge tube in which the cylindrical metal pipe is welded to the end is pressed against the inner wall of the discharge tube. did.

  Therefore, the discharge electrode inserted into the discharge tube is temporarily fixed in the discharge tube, and in that state, the discharge to the discharge tube, the replacement of the rare gas and the introduction of the sealed gas, and the discharge electrode hermetically sealed with respect to the discharge tube A fixing and fixing process or the like can be performed. As a result, there is no need to provide a support means (mechanism) for supporting the discharge electrode outside, and it is possible to suppress the complexity of the structure of the apparatus used in the exhaust, rare gas replacement and sealed gas introduction processes.

  Further, in the heating and melting step of the metal pipe and the discharge electrode, both can be heated and melt-bonded by one-point concentrated irradiation of laser light from the central axis direction of the discharge tube. As a result, it is possible to improve the work efficiency in the heating and melting step.

  Furthermore, the metal pipe can be used as a support fixing portion when the discharge lamp is attached, and at the same time, a power receiving electrode for supplying power from an external power source. For this reason, when the discharge lamp is used in an environment where it is exposed to mechanical vibration or impact such as in-vehicle use, external vibration or impact is applied to the metal pipe that holds the discharge lamp, and the electrode related to discharge light emission. There is no direct vibration or shock.

  Therefore, it is possible to maintain a very stable discharge light emission even when used in a severe environment with vibrations and shocks, and an extremely reliable discharge lamp is realized.

It is side surface explanatory drawing of the high pressure discharge lamp of embodiment. It is a longitudinal cross-sectional explanatory drawing of FIG. It is explanatory drawing of the manufacturing process of a high pressure discharge lamp. Similarly, it is explanatory drawing of the manufacturing process of a high pressure discharge lamp. Similarly, it is explanatory drawing of the manufacturing process of a high pressure discharge lamp. Similarly, it is explanatory drawing of the manufacturing process of a high pressure discharge lamp. Similarly, it is explanatory drawing of the manufacturing process of a high pressure discharge lamp. It is explanatory drawing which shows the relationship between an electrode and a metal pipe. It is explanatory drawing of an electrode. It is explanatory drawing which shows the relationship between a discharge tube, a metal pipe, and an electrode. It is explanatory drawing of a prior art example.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. 1 to 10 (the same parts are denoted by the same reference numerals). The embodiments described below are preferable specific examples of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention particularly limits the present invention in the following description. Unless stated to the effect, the present invention is not limited to these embodiments.

  FIG. 1 is a side view for explaining the configuration of a high-pressure discharge lamp according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view for explaining FIG.

  A high-pressure discharge lamp (hereinafter abbreviated as a discharge lamp) 1 includes a discharge tube 10 made of translucent ceramics, each of which is a pair of metal pipes made of a refractory metal such as tantalum, tungsten, or molybdenum. 20 and a pair of discharge electrodes (hereinafter abbreviated as “electrodes”) 30.

  The discharge tube 10 includes a cylindrical large tube portion 11 and a pair of cylindrical thin tubes extending from both ends of the large tube portion 11 with a diameter (inner diameter and outer diameter) smaller than the diameter (inner diameter and outer diameter) of the thick tube portion 11. The metal pipe 20 has a cylindrical large diameter portion 21 and a diameter (inner diameter and outer diameter) smaller than the diameter (inner diameter and outer diameter) of the large diameter portion 21 from one end of the large diameter portion 21. It is comprised with the cylindrical small diameter part 22 extended. The discharge tube 10 and the metal pipe 20 are all formed with a uniform thickness.

  Each metal pipe 20 is formed such that the inner diameter of the large-diameter portion 21 is slightly larger than the outer diameter of the thin tube portion 12 of the discharge tube 10, and a metal pipe is formed at each end of the pair of thin tube portions 12 of the discharge tube 10. The discharge tube 10 and the metal pipe 20 are hermetically sealed and fixed to each other by covering the large diameter portion 21 of the 20 and welding them together with the frit 2.

  Each electrode 30 has a columnar tip electrode portion 31 that is an electrode related to discharge light emission, and a columnar electrode shaft 32 that extends from one side of the tip electrode portion 31 with a larger diameter than the tip electrode portion 31. At least the electrode shaft 32 has a curved shape in the longitudinal direction.

  In each electrode 30, the electrode shaft 32 is inserted into the narrow tube portion 12 of the discharge tube 10 and the small diameter portion 22 of the metal pipe 20 with the tip electrode portion 31 positioned in the thick tube portion 11 of the discharge tube 10. Has been. At this time, the curved electrode shaft 32 of the electrode 30 inserted into the narrow tube portion 12 of the discharge tube 10 is near the tip (A portion) of the inner wall 13 of the thin tube portion 12 and near the end portion on the large tube portion 11 side (B Part) is in contact (pressure contact).

  Further, the small diameter portion 22 of the metal pipe 20 and the electrode shaft 32 of the electrode 30 are integrally heated and melted at the tip portion of the small diameter portion 22 to form the melted portion 3 and are hermetically fused and fixed to each other.

  As a result, the electrode 30 is fixed to the discharge tube 10 via the metal pipe 20, and the space in the thick tube portion 11 of the discharge tube 10 is a completely airtight discharge space 4 by the metal pipe 20 and the electrode 30. .

  Further, in the discharge space 4, for example, a sealed gas 5 such as a gas containing xenon as a main component is sealed, and the tip electrode portion 31 of the electrode 30 located in the discharge space 4 melts the electrode shaft 32. It is electrically connected to the small diameter portion 22 of the metal pipe 20 through the portion 3.

  Therefore, when mounting and fixing the discharge lamp 1 and discharge light emission, the metal pipe 20 is connected and fixed to a support fixing member that is electrically connected to an external power source and also has a function of supporting and fixing the discharge lamp 1. The discharge lamp 1 can be held at a predetermined position via the pipe 20, and the received power received from the support fixing member via the metal pipe 20 is supplied to the tip electrode portion 31 of the electrode 30 to supply the discharge lamp 1. Discharge emission can be started and maintained.

  That is, the metal pipe 20 of the discharge lamp 1 serves both as a structural support portion and as an electrical power receiving electrode portion.

  As a result, when the discharge lamp 1 is used in an environment where it is exposed to mechanical vibrations or shocks such as in-vehicle use, external vibrations or shocks are applied to the metal pipe 20 that holds the discharge lamp 1, and the discharge No vibration or impact is directly applied to the electrode 3 related to light emission.

  Therefore, even when used in a severe environment with vibration and impact, it is possible to maintain a very stable discharge light emission, and the discharge lamp 1 with extremely high reliability is realized.

  Next, a method for manufacturing the discharge lamp 1 according to the above embodiment will be described.

  First, as shown in FIG. 3 (an explanatory diagram of a manufacturing process of a discharge lamp), the diameter (inner diameter and the inner diameter and the diameter of the thick tube portion 11 from both ends of the cylindrical thick tube portion 11 and the thick tube portion 11 is made of translucent ceramics. The cylindrical large diameter is formed by the discharge tube 10 constituted by a pair of cylindrical thin tube portions 12 extending with a smaller diameter (inner diameter and outer diameter) than the outer diameter, and a refractory metal such as tantalum, tungsten, and molybdenum. A metal pipe 20 composed of a portion 21 and a cylindrical small-diameter portion 22 extending from one end of the large-diameter portion 21 with a diameter (inner diameter and outer diameter) smaller than the diameter (inner diameter and outer diameter) of the large-diameter portion 21. The large-diameter portion 21 of the metal pipe 20 is covered with the end portion of the narrow tube portion 12 on one side (primary side) of the discharge tube 10, and both are hermetically welded and fixed by the frit 2.

  Therefore, the inner diameter of the large diameter portion 21 of the metal pipe 20 is formed to be slightly larger than the outer diameter of the narrow tube portion 12 of the discharge tube 10. Further, both the discharge tube 10 and the metal pipe 20 are formed to have a uniform thickness as a whole.

  Next, a cylindrical tip electrode portion 31 that is formed of a refractory metal such as tantalum, tungsten, molybdenum, etc., and serves as an electrode portion related to discharge light emission, as shown in FIG. An electrode 30 having a cylindrical electrode shaft 32 extending from one side of the tip electrode portion 31 with a diameter larger than that of the tip electrode portion 31 and having at least the electrode shaft 32 curved in the longitudinal direction is shown in FIG. As shown in the explanatory diagram of the manufacturing process of the discharge lamp), the tip electrode portion 31 is inserted into the discharge tube 10 through the small diameter portion 22 of the metal pipe 20 from the tip electrode portion 31 side, and the tip electrode portion 31 is inserted into the thick tube portion 11 of the discharge tube 10. Set (temporarily fixed) in a state of being located near the inner end.

  At this time, the distal end portion 33 of the electrode shaft 32 of the electrode 30 is flush with the distal end portion 23 of the small diameter portion 22 of the metal pipe 20 or slightly protrudes from the distal end portion 23 of the small diameter portion 22 of the metal pipe 20. Has been.

  In addition, the electrode 30 inserted into the discharge tube 10 has the electrode shaft 32 formed in a curved shape, so that the vicinity of the tip (A portion) of the inner wall 13 of the thin tube portion 12 of the discharge tube 10 and the large tube portion 11 side. Are in contact with each other at two locations in the vicinity of the end portion (B portion) and pressed by the urging force of the curved electrode shaft 32.

  Therefore, next, as shown in FIG. 6 (an explanatory diagram of the manufacturing process of the discharge lamp), the tip of the electrode shaft 32 of the electrode 30 inserted into the discharge tube 10 to which the metal pipe 20 is welded and temporarily fixed by pressure welding. The portion 33 and the tip 23 of the small-diameter portion 22 of the metal pipe 20 are heated and melted by irradiating a laser beam at one point from the central axis (Z) direction of the discharge tube 10, and the two are integrated in an airtight manner. The melted part 3 is formed.

  Thereby, the electrode 30 is hermetically fixed to the primary side of the discharge tube 10 via the metal pipe 20.

  On the other hand, in the airtight treatment process on the secondary side of the discharge tube 10, at least the electrode 30 having a shape in which the electrode shaft 32 is curved in the longitudinal direction passes through the small diameter portion 22 of the metal pipe 20 from the tip electrode portion 31 side. The tip electrode portion 31 is positioned in the vicinity of the end portion in the thick tube portion 11 of the discharge tube 10, and the electrode 30 inserted in the discharge tube 10 is inserted into the inner wall 13 of the thin tube portion 12 of the discharge tube 10. A state of being in contact with two locations in the vicinity of the tip end (A portion) and in the vicinity of the end portion on the thick tube portion 11 side (B portion) and being in pressure contact with the urging force of the curved electrode shaft 32 (see FIG. 5). Until this is done, it is the same as the above-described primary-side airtight treatment process.

  Next, with respect to the airtight treatment process on the secondary side, exhaust from the secondary side of the discharge tube 10 to the inside of the discharge tube 10 (particularly within the thick tube portion 11 of the discharge tube 10), replacement of rare gas, and mainly xenon, for example. Introduce gas as component (filled gas 5). In this case, the exhaust, replacement, and introduction of gas into the discharge tube 10 are performed between the electrode shaft 32 of the electrode 30 and the inner wall 24 of the small-diameter portion 22 of the metal pipe 20 and between the electrode shaft 32 of the electrode 30 and the discharge tube 10. This is performed through a gap with the inner wall 13 of the narrow tube portion 12 (see FIG. 7 (an explanatory diagram of the manufacturing process of the discharge lamp)).

  Thereafter, in the same manner as in the airtight treatment process on the primary side, the distal end portion 33 of the electrode shaft 32 of the electrode 30 inserted into the discharge tube 10 to which the metal pipe 20 is welded and temporarily fixed by pressure, and the small diameter portion of the metal pipe 20 22 is irradiated with a laser beam at one point from the central axis (Z) direction of the discharge tube 10 and heated and melted to form a melted portion 3 in which both are hermetically integrated (see FIG. 6).

  As a result, the electrode 30 is hermetically fixed to the primary side and the secondary side of the discharge tube 10 via the pair of metal pipes 20, and the sealed gas 5 containing xenon as a main component is contained in the discharge space 4 of the discharge tube 10. The discharge lamp 1 hermetically sealed is completed (see FIG. 2).

  In the heating and melting step by laser light irradiation of the tip portion 33 of the electrode shaft 32 of the electrode 30 and the tip portion 23 of the small diameter portion 22 of the metal pipe 20, the melting portion 3 is reliably formed and hermetically sealed by both. In order to achieve high reliability, an optimum dimensional relationship between the tip 33 of the electrode shaft 32 of the electrode 30 and the tip 2 of the small diameter portion 22 of the metal pipe 20 was derived based on a prototype test or the like.

  Specifically, as shown in FIG. 8 (an explanatory diagram showing the relationship between the electrode and the metal pipe), the diameter of the electrode shaft 32 of the electrode 30 is D0, the inner diameter of the small-diameter portion 22 of the metal pipe 20 is D1, and the outer When the diameter is D2, it is preferable to satisfy the relationship of 0 <(D1-D0) / (D2-D1) ≦ 0.6.

  If the relationship of (D1−D0) / (D2−D1)> 0.6 is satisfied, the small diameter of the metal pipe 20 with respect to the gap between the electrode shaft 32 of the electrode 30 and the inner wall 24 of the small diameter portion 22 of the metal pipe 20. The thickness of the portion 22 is relatively thin. As a result, the melt amount of the small diameter portion 22 of the metal pipe 20 may not ensure a sufficient melt amount to completely fill the gap with good reproducibility, and form a reliable complete hermetic seal. There is a risk of not being able to.

  The electrode 30 has a shape in which at least the electrode shaft 32 is curved in the longitudinal direction. When the electrode 30 is inserted into the discharge tube 10 (particularly, the narrow tube portion 12 of the discharge tube 10), the center axis ( It is also eccentric with respect to (Z), which is also the central axis of the narrow tube portion 12 of the discharge tube 10. Therefore, the position of the tip of the tip electrode portion 31 of the electrode 30 located in the thick tube portion 11 of the discharge tube 10 is a circumferential direction (XY direction) centered on the central axis (Z) and a central axis (Z ) In a non-uniform arrangement along the direction (Z direction), and the individual discharge lamps 1 have different discharge emission characteristics.

  On the other hand, when the electrode 30 of this embodiment produces the length of the tip electrode part 31, the length of the electrode shaft 32, and the curved shape with good reproducibility and inserts it into the discharge tube 10, the small diameter of the metal pipe 20 The direction (Z direction) along the central axis (Z) of the tip of the tip electrode part 31 of the electrode 30 by making the positional relationship between the tip part 23 of the part 22 and the tip part 33 of the electrode shaft 32 of the electrode 30 constant. The center 30 is centered on the central axis (Z) of the tip of the tip electrode portion 31 of the electrode 30 by ensuring the reproducibility of the position of the electrode 30 and making the bending direction of the electrode 30 a constant radiation direction centered on the center axis (Z). The reproducibility of the position in the circumferential direction (XY direction) is ensured (see FIG. 5).

  Therefore, in the discharge lamp 1 using the curved electrode 30, the tip of the tip electrode portion 31 of the electrode 30 is positioned with good reproducibility in each direction of XYZ of the discharge tube 10, and each discharge lamp 1 1 have uniform discharge light emission characteristics.

  Further, in the manufacturing process of the discharge lamp 1, exhaust to the inside of the discharge tube 10 (particularly in the thick tube portion 11 of the discharge tube 10) in a state where the curved electrode 30 is inserted into the discharge tube 10 and temporarily fixed by pressure welding. The replacement of the rare gas and the introduction of the gas mainly containing xenon (encapsulated gas 5) are performed.

  Therefore, it is not necessary to provide a support means (mechanism) for supporting the electrode 30 outside, and the structure of the processing apparatus used in the gas processing process such as exhaust, replacement of rare gas and introduction of sealed gas is complicated. Absent. As a result, an increase in the price of the processing apparatus is suppressed, and the manufacturing cost of the product (high pressure discharge lamp) can be kept low.

  Further, when the small diameter portion 22 of the metal pipe 20 and the electrode shaft 32 of the electrode 30 are heated and melted, the tip portion 33 of the electrode shaft 32 of the electrode 30 and the tip portion 23 of the small diameter portion 22 of the metal pipe 20 are close to each other. The portion can be heated and melted by irradiating the laser beam at a single point from the central axis (Z) direction of the discharge tube 10.

  Therefore, the work efficiency in the heating and melting process can be improved, and the manufacturing cost of the product (high pressure discharge lamp) can be kept low.

  The shape of the electrode 30 is not limited to the curved shape having one curved portion as in the above embodiment, and at least the electrode shaft 32 is in the longitudinal direction as shown in FIG. It is good also as a shape which exhibits the waveform which has two or more places (FIG. 9 is two places specifically).

  Also in this case, as in the above embodiment, the length of the tip electrode portion 31 of the electrode 30, the length of the electrode shaft 32, and the curved shape are manufactured with good reproducibility and inserted into the discharge tube 10 as shown in FIG. As shown in the explanatory diagram showing the relationship between the tube, the metal pipe, and the electrode, the positional relationship between the tip 23 of the small diameter portion 22 of the metal pipe 20 and the tip 33 of the electrode shaft 32 of the electrode 30 is made constant. Thus, the reproducibility of the position of the tip of the tip electrode portion 31 of the electrode 30 in the direction (Z direction) along the center axis (Z) is ensured, and the bending direction of the electrode 30 is constant around the center axis (Z). By setting the radial direction, the reproducibility of the position in the circumferential direction (XY direction) around the central axis (Z) of the tip of the tip electrode portion 31 of the electrode 30 is ensured.

  At this time, the corrugated electrode shaft 32 of the electrode 30 inserted into the narrow tube portion 12 of the discharge tube 10 has two or more locations on the inner wall 13 of the thin tube portion 12 (specifically, in the vicinity of the tip (A portion) and the center in FIG. 10). 2 parts in the vicinity of the part (B part)).

  Thereby, in the discharge lamp using the wave-shaped electrode 30, the tip of the tip electrode portion 31 of the electrode 30 is positioned with good reproducibility in each direction of XYZ of the discharge tube 10, and each discharge lamp Have uniform discharge emission characteristics.

DESCRIPTION OF SYMBOLS 1 ... High pressure discharge lamp 2 ... Frit 3 ... Melting part 4 ... Discharge space 5 ... Filling gas 10 ... Discharge tube 11 ... Thick tube part 12 ... Thin tube part 13 ... Inner wall 20 ... Metal pipe 21 ... Large diameter part 22 ... Small diameter part 23 ... tip part 24 ... inner wall 30 ... discharge electrode 31 ... tip electrode part 32 ... electrode shaft 33 ... tip part

Claims (2)

A cylindrical discharge tube having a thick tube portion and a thin tube portion having a diameter smaller than that of the thick tube portion located on both sides of the thick tube portion, and a uniform overall thickness,
The large-diameter portion and the large-diameter portion have a small-diameter portion smaller in diameter than the large-diameter portion located on one side, and the both ends of the large-diameter portion cover both ends of the thin-tube portion of the discharge tube. A cylindrical metal pipe having a uniform overall wall thickness, wherein the large-diameter portion is hermetically welded to the portion,
A tip electrode portion having a predetermined length and an electrode shaft extending by a predetermined length from one side of the tip electrode portion, and the electrode shaft is integrally fused to a tip portion of a small diameter portion of the metal pipe. And a discharge electrode that is inserted through the narrow tube portion of the discharge tube and the tip electrode portion reaches the inside of the thick tube portion, and a high-pressure discharge lamp comprising:
The discharge electrode has a shape in which at least the electrode axis is curved in the longitudinal direction or a wave shape having two or more curved portions,
A high-pressure discharge lamp, wherein the electrode axis of the discharge electrode inserted through the narrow tube portion of the discharge tube is in pressure contact with two or more locations on the inner wall of the narrow tube portion.   When the diameter of the electrode axis of the discharge electrode is D0, the inner diameter of the small-diameter portion of the metal pipe is D1, and the outer diameter is D2, a relation of 0 <(D1-D0) / (D2-D1) ≦ 0.6 The high pressure discharge lamp according to claim 1, wherein:

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