JP2013089480A - Foil seal lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foil seal lamp capable of reinforcing a connection between a metal foil and an electrode while suppressing a crack leakage.SOLUTION: There is provided the foil seal lamp including a light emission part 11 which has a discharge space 111 inside, an airtight container 1 having a seal part 12 formed so as to be connected to the light emission part 11, a metal foil 31 sealed to the seal part 12, and an electrode 32 having one end connected to the metal foil 31 and the other end arranged so as to project into the discharge space. The metal foil 31 has, on its plate surface, a processed part 311 having been subjected to roughening processing and an unprocessed part 312 having been subjected to no roughening processing, and the electrode 32 is welded to the metal foil 31 while placed on the unprocessed part 312.

Description

  Embodiments described herein relate generally to a foil seal lamp used for a vehicle headlamp, a liquid crystal projector, and the like.

  In general, the foil seal lamp has a structure including a pair of seal portions at both ends of a light emitting portion including a discharge space. A metal foil welded with an electrode is sealed to the seal portion.

  In such a foil seal lamp, the surface of the metal foil may be subjected to uneven treatment by laser irradiation, sand blasting, etching or the like. When the surface of the metal foil is subjected to uneven treatment, the adhesion between the glass constituting the seal portion and the metal foil can be improved, the metal foil and the glass are peeled off, and the glass is cracked, and the gas in the discharge space is generated. It is possible to suppress a phenomenon that the lamp is not turned on due to leakage or the like.

  However, in the case of using a metal foil whose surface has been subjected to unevenness treatment, there is a problem that the metal foil and the electrode are unwelded.

Patent 4367714 Japanese Patent No. 4681668 Patent 3150918 Patent 3648184

  The problem to be solved by the present invention is to provide a foil seal lamp capable of reinforcing the connection between a metal foil and an electrode while suppressing crack leakage.

  In order to achieve the above object, the foil seal lamp of the embodiment includes a light emitting part having a discharge space therein, an airtight container having a seal part formed so as to be continuous with the light emitting part, and a seal in the seal part. A foil seal lamp comprising: an attached metal foil; and one end connected to the metal foil and the other end arranged to protrude into the discharge space, on a plate surface of the metal foil Is provided with a processed portion that has been subjected to a rough surface treatment and an unprocessed portion that has not been subjected to the rough surface treatment, and the electrode is placed on the unprocessed portion, It is welded.

It is a figure for demonstrating the side view of the foil seal lamp of 1st Embodiment. It is a figure for demonstrating the top view of the foil seal lamp of 1st Embodiment. It is a figure for demonstrating the A-A 'cross section of FIG. 2 of the foil seal lamp of 1st Embodiment. It is a figure for demonstrating the range B of FIG. 2 of the foil seal lamp of 1st Embodiment. It is a figure for demonstrating the metal foil of the foil seal lamp of 1st Embodiment. It is a figure for demonstrating the cross section of the welding part vicinity of the electrode and metal foil of the conventional foil seal lamp. It is a figure for demonstrating the relationship W / D of the width W of an unprocessed part, and the diameter D of an electrode, and the incidence rate of a crack leak.

(First embodiment)
The first embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a view for explaining a side view of a foil seal lamp according to the first embodiment of the present invention, and FIG. 2 is a top view of the foil seal lamp according to the first embodiment of the present invention. FIG.

  The foil seal lamp of this embodiment can be used as a light source for a headlamp of an automobile or the like, and includes an inner tube 1 as an airtight container. The inner tube 1 has an elongated shape, and a substantially elliptical light emitting portion 11 is formed near the center thereof. A plate-like seal portion 12 formed by a pinch seal is formed at both ends of the light emitting portion 11, and a cylindrical portion 14 is continuously formed at both ends via a boundary portion 13. The inner tube 1 is preferably made of a material having heat resistance and translucency, such as quartz glass. Further, the seal portion 12 may be formed in a cylindrical shape by being formed by a shrink seal.

  A discharge space 111 having a substantially cylindrical shape at the center and having a diameter that decreases toward both ends is formed inside the light emitting unit 11. The discharge space 111 is filled with the metal halide 2 and the rare gas.

  The metal halide 2 is composed of sodium iodide, scandium iodide, zinc iodide, and indium bromide. The total enclosed amount of the metal halide 2 is set to 0.1 mg to 0.3 mg in order to set the lamp voltage to a suitable value. The combination of the metal halides 2 is not limited to this, and tin and cesium halides may be added.

  Xenon is used as the rare gas. The pressure of the rare gas is 11 atm to 15 atm. Note that the rare gas may be a mixed gas of xenon and neon, argon, krypton, or the like.

  Here, the lamp of the present embodiment does not substantially contain mercury. The phrase “substantially does not contain mercury” in the present specification is not limited to the case where the amount of mercury enclosed is 0 mg, but is almost equal to the case where it is hardly enclosed as compared with a conventional foil sealed lamp containing mercury. The amount of mercury, for example, less than 2 mg per ml, preferably less than 1 mg of mercury is encapsulated.

  The electrode mounts 3 are sealed to the seal portions 12 formed on both sides of the light emitting portion 11, respectively. The electrode mount 3 includes a metal foil 31, an electrode 32, a coil 33 and a lead wire 34.

  The metal foil 31 is a thin plate member made of, for example, molybdenum.

  The electrode 32 is a rod-like member made of, for example, triated tungsten obtained by doping tungsten with thorium oxide. One end of the metal foil 31 is laser-welded in a state of being placed on the end of the light emitting unit 11 side, and the other end protrudes into the discharge space 111, and the tips of each other are kept at a predetermined distance. It is opposed to face each other. In the case of an automotive headlamp application, it is preferable that the distance between the tips of the electrodes 32 is positioned in a range of 3.7 mm to 4.4 mm when observed through the outer tube 5.

  The coil 33 is a metal wire made of, for example, doped tungsten, and is spirally wound around the axis of the shaft portion of the electrode 32 sealed to the seal portion 12.

  The lead wire 34 is a metal wire made of molybdenum, for example. One end of the lead wire 34 is connected so as to be placed on the end portion of the metal foil 31 on the distal side from the light emitting portion 11, and the other end extends substantially parallel to the tube axis to the outside of the inner tube 1. Has been. One end of an L-shaped support wire 35 made of nickel, for example, is connected to the lead wire 34 extending distally from the front side of the lamp, that is, the socket 6 by laser welding. For example, a sleeve 4 made of ceramic is attached to the support wire 35 at a portion extending in parallel with the inner tube 1.

  On the outside of the inner tube 1 configured as described above, a cylindrical outer tube 5 is provided substantially concentrically with the inner tube 1 so as to cover the light emitting portion 11. These inner and outer pipes are connected by welding the end portions of the outer pipe 5 in the vicinity of the cylindrical portion 14 of the inner pipe 1. Gas is sealed in a closed space 51 formed between the inner tube 1 and the outer tube 5. As this gas, a gas capable of dielectric barrier discharge, for example, one kind of gas selected from neon, argon, xenon and nitrogen or a mixed gas can be used. The gas pressure is desirably 0.3 atm or less, particularly 0.1 atm or less. The outer tube 5 is preferably made of a material having a thermal expansion coefficient close to that of the inner tube 1 and having an ultraviolet blocking property. For example, quartz glass to which an oxide such as titanium, cerium, or aluminum is added is used. can do.

  A socket 6 is connected to one end of the inner tube 1 to which the outer tube 5 is connected. These connections are made by attaching a metal band 71 to the outer peripheral surface of the outer tube 5 and holding the metal band 71 with four metal tongues 72 projecting from the socket 6. Further, a bottom terminal 81 is formed at the bottom of the socket 6, and a side terminal 82 is formed at the side, and a lead wire 34 and a support wire 35 are connected to the bottom terminal 81 and the side terminal 82, respectively. .

  The foil-sealed lamp composed of these is connected to a lighting circuit (not shown) so that the bottom terminal 81 is on the high voltage side and the side terminal 82 is on the low voltage side. Lights up to 35W.

  Here, in the present embodiment, as shown in FIGS. 3 and 4, a processed portion 311 is formed on the plate surface of the metal foil 31. The processed portion 311 is a rough surface composed of a plurality of recesses, and the range of formation thereof is about a half surface of the metal foil 31 (however, the edge portion such as a knife edge is excluded). The plurality of recesses are in contact with each other in the width direction and the length direction of the metal foil 31. The dent can be obtained by performing a rough surface treatment by laser irradiation. Specifically, it can be obtained by repeatedly performing a process of forming a non-penetrating recess on the surface of the metal foil 31 with a YAG laser. When the rough surface treatment is performed by laser irradiation, the size, depth, number, and regions to be formed and regions to be formed can be freely controlled.

  Further, as shown in FIG. 5, an unprocessed portion 312 is also formed on the plate surface of the metal foil 31. The unprocessed portion 312 is a portion that is within the range of the processed portion 311 and is not subjected to the rough surface treatment, is not rougher than the processed portion 311, and is substantially flat. The unprocessed portion 312 is provided at a place where the electrode 32 is placed as shown in FIGS. In this example, the surface on the side where the electrode 32 is not placed is also formed at a corresponding position on the front and back sides. That is, welding of the metal foil 31 and the electrode 32 is performed in the unprocessed portion 312. When laser welding is performed, a melted portion 313 is formed from one unprocessed portion 312 to be connected to the other unprocessed portion 312 and a part of the electrode 32.

  One specification of the embodiment of the discharge lamp of the present invention is shown below.

Inner tube 1: made of quartz glass, inner volume of light emitting part 11 = 27.5 mm ³ , inner diameter = 2.5 mm, outer diameter = 6.2 mm, sphere length in the longitudinal direction = 7.8 mm,
Metal halide 2: ScI ₃ = 0.068 mg, NaI = 0.109 mg, ZnI ₂ = 0.022 mg, InBr = 0.005 mg,
Noble gas: xenon = 13.5 atm,
Mercury: 0 mg,
Metal foils 31, 31: made of molybdenum, length = 6.5mm, width = 1.5mm, thickness = 20mm,
Processed portion 311: Formation range = 3.0 mm × 1.3 mm, dent diameter = 18 μm, depth 3 μm,
Unprocessed portion 312: formed on the portion where the electrode 32 is placed, and further formed at the same position on the back surface, length L1 = 1.0 mm, width W = 0.39 mm,
Electrodes 32, 32: made of triated tungsten, diameter D = 0.38 mm, distance between electrodes = 4.2 mm (actual distance between electrodes = 3.75 mm), placement length L2 on metal foil 31 = 0.9 mm,
Coils 33, 33: Made of doped tungsten, wire diameter = 0.06 mm, pitch = 250%, winding length = 3.2 mm,
External lead wires 34, 34: made of molybdenum, diameter = 0.6 mm.

  When the tensile test was performed on the electrode mount 3 of the conventional example in which the electrode mount 3 and the unprocessed part 312 of this example also formed the processed part 311, the example was 1.3 times as large as the conventional example. It was confirmed that the connection strength of was strong. This is because the electrode 32 is placed on the unprocessed portion 312 which is a flat surface and welded in the embodiment, whereas the electrode 32 is placed on the surface of the metal foil 31 on the surface of the metal foil 31 in the conventional example. This is considered to be a difference caused by placing and welding. That is, in the conventional example, a thick portion and a thin portion where the electrode 32 is welded are formed by the uneven treatment, and the welding strength becomes unstable due to the variation, and the electrode 32 and the metal foil 31 are easily detached. It is thought that the connection strength was higher than that of the example.

  Next, a lighting test in the EU rated mode was performed on the lamp of the example in which the electrode mounts 3 were sealed and the lamp of the conventional example. As a result, the crack leak did not occur even when the example was lit for 2000 hours, whereas the crack occurred in about 100 hours in the conventional example.

  In the conventional example, the crack leak occurred at a location as shown in FIG. This is a crack leak called a shaft end leak that causes a crack in the glass in contact with the electrode shaft and leads to a leak. Therefore, it is considered that the difference in the occurrence time of crack leak between the example and the conventional example is related to the adhesion of the glass around the axis of the electrode 32. Comparing FIG. 3 which is the example and FIG. 6 which is the conventional example, the gap 9 formed between the vicinity of the welded portion of the metal foil 31 and the electrode 32 and the seal portion 12 is larger in FIG. 6 than in FIG. It is getting smaller. In particular, in the conventional example, the glass is in close contact with the periphery of the electrode axis in a wider range than in the example. If the glass is excessively adhered around the axis of the electrode 32 as in the conventional example, the metal constituting the electrode 32 and the glass constituting the seal portion 12 have different thermal expansion. It is considered that the electrode applied a strong stress to the glass during the thermal expansion and contraction, causing a shaft end leak.

As described above, the excessive adhesion of the glass around the axis of the electrode 32 in the conventional example is related to the processed portion 311 formed on the surface of the metal foil 31. When the processed portion 311 is formed by laser irradiation, molybdenum oxide such as MoO ₃ is formed on the surface by oxidation with laser energy. Then, when the process of sealing the electrode mount 3 to the seal part 12 is performed, the heat of the burner when the glass is heated is also transmitted to the metal foil 31, and the molybdenum oxide on the surface of the processed part 311 evaporates and the electrode It adheres to the surface of the 32 shafts, in particular the electrode surface facing the foil. Since this molybdenum oxide has good compatibility with glass, it is considered that as a result of passing through the sealing step, the glass adhered more excessively around the axis of the electrode 32 than in the example.

  Therefore, in order to clarify the relationship between the unprocessed portion 312 and the crack leak, the relationship W / D between the width W of the unprocessed portion 312 and the diameter D of the electrode 32 is changed based on the above embodiment. A test was conducted on the occurrence rate of crack leak. The result is shown in FIG. The number of tests is 30.

  It can be seen from FIG. 7 that crack leakage occurs regardless of whether W / D is small or large. A crack leak that occurs when W / D is small is a shaft end leak. When W / D is less than 0.3, a shaft end leak occurs due to the mechanism described above. On the other hand, a crack leak that occurs when W / D is large is a so-called foil leak that is caused by peeling of the metal foil and glass to cause cracks in the glass. In other words, when W / D increases, the range in which the glass of the seal portion 12 and the unprocessed portion 312 are in close contact with each other and the adhesiveness is reduced, so that foil leakage is likely to occur, and W / D is higher than 1.3. The tendency to occur when it becomes large appears. Therefore, it can be said that W / D is preferably 0.3 ≦ W / D ≦ 1.3.

  In this embodiment, a processed portion 311 that has been subjected to a rough surface treatment and an unprocessed portion 312 that has not been subjected to a rough surface treatment are provided on the plate surface of the metal foil 31, and the electrode 32 is mounted on the unprocessed portion 312. Since the connection strength between the metal foil 31 and the electrode 32 can be increased by welding with the metal foil 31 in the placed state, it is possible to prevent problems in manufacturing due to the release of the connection particularly in the manufacturing process. can do. In addition, since the occurrence of crack leaks, particularly foil leaks, can be suppressed, a long-life and highly reliable lamp can be provided. If the unprocessed portion 312 is also formed on the back surface of the portion on which the electrode 32 is placed, the connection strength can be further increased.

  Further, when the diameter of the electrode 32 in the unprocessed portion 312 is D (mm) and the width along the diameter direction of the electrode of the unprocessed portion 312 is W (mm), 0.3 ≦ W / D ≦ 1.3 By satisfy | filling, it becomes possible to suppress generation | occurrence | production of not only foil leak but shaft end leak, and can provide a lamp with a long lifetime and high reliability.

  Further, by performing the rough surface treatment by laser irradiation, it is possible to easily control the processed portion 311 and the unprocessed portion 312. That is, the unprocessed portion 312 can be formed with high accuracy within the range of the processed portion 311.

  The present invention is not limited to the above embodiments, and various modifications are possible.

  For example, the shape of the electrode 32 is a stepped shape in which the diameter of the distal end is larger than the diameter of the proximal end, a shape in which the distal end is a sphere having a large diameter, or a shape in which one electrode diameter is different from the other electrode diameter. There may be. The electrode material may be pure tungsten, tungsten doped with aluminum, silicon, or potassium in a small amount, rhenium tungsten doped with rhenium in tungsten, or the like. The welding with the metal foil 31 may be resistance welding or the like.

The roughening treatment of the metal foil 31 may be any treatment that can make the foil surface rougher than before the treatment. For example, sand blasting or etching may be used. In particular, Al ₂ O ₃ or the like used as a blast material on the foil surface in sand blasting, and an etching material remains on the foil surface after the rough surface treatment in etching, which is the shaft of the electrode 32 in the sealing step in the same manner as molybdenum oxide. It is effective to carry out the present invention because it causes excessive glass adhesion to the surroundings. However, since the rough surface treatment makes it difficult to control the processed part 311 and the unprocessed part 312, laser irradiation is most optimal.

  Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Inner tube 11 Light emission part 111 Discharge space 2 Metal halide 3 Electrode mount 31 Metal foil 311 Processed part 312 Unprocessed part 32 Electrode

Claims (3)

A light emitting part having a discharge space inside, an airtight container provided with a seal part formed so as to be continuous with the light emission part, a metal foil sealed to the seal part, and one end connected to the metal foil, The other end is an electrode disposed so as to protrude into the discharge space, and a foil seal lamp comprising:
On the plate | board surface of the said metal foil, it provided with the process part to which the rough surface process was given, and the unprocessed part to which the said rough surface process was not given, The said electrode was mounted in the said non-process part A foil seal lamp characterized by being welded to the metal foil in a state.   When the diameter of the electrode in the unprocessed portion is D (mm) and the width along the diameter direction of the electrode of the unprocessed portion is W (mm), 0.3 ≦ W / D ≦ 1.3 is satisfied. The foil-sealed lamp according to claim 1.   The foil seal lamp according to claim 1, wherein the rough surface treatment is laser irradiation.

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