Short arc type discharge lamp and method for manufacturing the same

Abstract

To suppress peeling of a metal foil in a short arc type discharge lamp in which a metal foil is sealed in a sealed tube.SOLUTION: In a short arc type discharge lamp 10, mounting components are enclosed in sealed tubes 13A and 13B connected to both sides of a discharge tube 12. A metal film 40 is formed on the sealed tube 13A. The metal film 40 is electrically connected to a base 19A provided on the sealed tube 13A by a metal wire 50. In addition, platinum 60 is wound around the metal wire 50.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a short arc type discharge lamp, and more particularly to a sealing structure of the lamp. [Background technology]

[0002] In short arc type discharge lamps, a foil seal structure is adopted in which metal foil is sealed in the sealing tubes connected to both ends of the discharge tube, in which a mounting part including a cylindrical glass member that holds the electrode support rod and a strip of metal foil that electrically connects the electrode support rod to an external lead rod is inserted into the sealing tube and sealed to maintain airtightness.

[0003] The strip-shaped metal foils extend along the lamp axis, spaced apart from each other in the circumferential direction of the glass member, and are sandwiched and tightly attached between the sealing tube and the glass member. In order to improve the pressure resistance of the discharge lamp, it is necessary to increase the adhesion of the metal foils.

[0004] On the other hand, alkali metals exist as impurities in the electrode members and glass members. When the lamp is turned on, the alkali metals dissolved in the glass members are ionized and are electrically attracted to the same potential as the cathode, where they accumulate. The accumulation of alkali metals around the metal foil causes the foil to float or peel off, reducing the adhesion strength.

[0005] To prevent this, for example, a conductive member such as a conductive film is formed on the outer circumferential surface of the sealed tube and a lead wire is connected to it (see Patent Document 1). By connecting the lead wire to the cathode side lead rod and setting it to the same potential as the cathode, the alkali metal ions are prevented from migrating near the metal foil. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2010-118166 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, with the lead wire connection described in Patent Document 1, it is difficult to sufficiently prevent the migration of alkali metal ions to the vicinity of the metal foil, and as the lamp is lit for an extended period of time, the alkali metal ions migrate to the vicinity of the metal foil of the sealed tube, which can cause the foil to peel off and reduce the voltage resistance of the lamp.

[0008] Therefore, in a short arc type discharge lamp in which a metal foil is sealed in a sealed tube, it is necessary to suppress peeling of the metal foil. [Means for solving the problem]

[0009] The short arc type discharge lamp of the present invention comprises a discharge tube in which a pair of electrodes are arranged opposite to each other, and a sealed tube connected to both sides of the discharge tube, and a metal film is formed on the outer surface of at least one of the sealed tubes. Also, a metal wire is provided to electrically connect the metal film and at least one of the electrodes according to the metal film provided on at least one of the sealed tubes.

[0010] There are various configurations for the electrical connection between the metal film and the electrodes. For example, the metal film can be electrically connected to a base provided on at least one of the sealing tubes. Alternatively, the metal film can be electrically connected to a lead rod extending from the end of the sealing tube.

[0011] In the present invention, a metal member is provided around the sealing tube on which the metal film is formed, and is in contact with at least a part of the metal wire. Here, "around the sealing tube on which the metal film is formed" means that the metal member is provided around the sealing tube on which the metal film is formed, for example, when the metal film is formed only on one sealing tube, the metal member is provided around that sealing tube. In the sealing tube, the metal member can be provided over the area on which the metal film is formed, the area on the outer surface on which the metal film is not formed, or both of these areas.

[0012] The metal member may have a variety of configurations, and may be at least partially linear. Alternatively, the entire metal member may be linear. Regarding the configuration regarding the contact between the metal wire and the metal member, various contact methods are possible.

[0013] For example, the metal member may have a linear winding portion that is wound around a metal wire. When the metal wire has a portion that extends along the lamp axis, the linear metal may be wound around the metal wire as the winding portion and be in contact with the metal wire.

[0014] For example, the metal member may have a linear wound portion wound around the metal film. When the metal wire has a portion wound around the sealing tube, a linear metal may be wound as the wound portion and be in contact with the metal wire.

[0015] The metal film formed around the sealing tube can be formed in layers. For example, a metal film can be further formed on the wound portion of the metal member wound around the metal film. That is, the metal film can be configured to include a metal film formed around the outer surface of the sealing tube and a metal film formed on the wound portion of the metal member.

[0016] The metal member may be made of various materials, and may be made of the same material as the metal wire or a different material than the metal wire. The metal member may be made to have a lower resistance than the metal wire at least in the contact area with the metal wire. For example, the metal member may be made to at least partially contain platinum.

[0017] The number of metal wires and the number of metal members (e.g., the number of linear metals) may vary, and multiple metal wires and multiple metal members may be provided. For example, multiple metal wires and multiple metal members (e.g., linear metal wires) may be configured so that corresponding wires and members contact each other, or at least one set of wires and members contact each other, or one or multiple metal wires contact one metal member or multiple metal members.

[0018] Another aspect of the present invention is a method for manufacturing a short arc type discharge lamp, which comprises forming a metal film on the outer surface of at least one of the sealed tubes connected to both sides of the discharge tube, electrically connecting the metal film and a base provided on the sealed tube on which the metal film is formed by a metal wire, and bringing a linear metal member into contact with the metal wire. For example, the linear metal member can be wound around the metal wire. Also, the linear metal member can be wound so as to be in contact with the part of the metal wire wound around the sealed tube, and / or be configured to be in contact with the part extending in the axial direction of the lamp in a straight state. For example, the linear metal member can be wound around the sealed tube to be in contact with the metal wire, and a metal film can be further formed on the metal member wound on the metal film. Effect of the Invention

[0019] According to the present invention, in a short arc type discharge lamp in which a metal foil is sealed in a sealing tube, peeling of the metal foil can be suppressed. [Brief description of the drawings]

[0020] [Figure 1] 1 is a schematic plan view of a short arc type discharge lamp according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing a schematic diagram of a sealing portion on the cathode side of a short arc type discharge lamp. [Diagram 3] FIG. 13 is a diagram showing a modified example of the short arc type discharge lamp of the present embodiment. [Figure 4]11A and 11B are diagrams showing other modified examples of the short arc type discharge lamp of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, a short arc type discharge lamp according to the present embodiment will be described with reference to the drawings.

[0022] FIG. 1 is a schematic plan view of a short arc type discharge lamp according to this embodiment.

[0023] A short arc type discharge lamp 10 includes a transparent quartz glass discharge tube (light emitting tube) 12, within which a pair of electrodes 20, 30 made of tungsten or the like are coaxially arranged along the lamp axis C. On both sides of the bulb-shaped discharge tube 12, sealing tubes 13A, 13B made of quartz glass are connected to and integrally formed with the discharge tube 12. A discharge space DS within the discharge tube 12 is filled with mercury and a discharge gas (rare gas).

[0024] The cathode electrode 20 is supported by an electrode support rod 17A. Sealed in the sealed tube 13A are mounting parts such as a glass tube (not shown here) through which the electrode support rod 17A is inserted, a lead rod 15A that connects to an external power source, and a metal foil 16A that connects the electrode support rod 17A and the lead rod 15A.

[0025] In the anode electrode 30, mounting parts such as a glass tube (not shown) through which an electrode support rod 17B is inserted, metal foil 16B, and lead rod 15B are also sealed. Bases 19A and 19B are attached to the ends of the sealed tubes 13A and 13B, respectively.

[0026] When a voltage is applied to the pair of electrodes 20, 30, an arc discharge occurs between the electrodes 20, 30, and light is emitted toward the outside of the discharge tube 12. The light emitted from the discharge tube 12 is guided in a predetermined direction by, for example, a reflecting mirror (not shown).

[0027] 2 is a diagram showing a schematic diagram of a sealing portion on the cathode side of the short arc type discharge lamp 10. However, parts such as metal foil and an electrode support rod are not shown.

[0028] A metal film 40 is formed on the cathode-side sealed tube 13A near the connection 13T with the discharge tube 12. A metal film 40 is also formed on the outer surface of the discharge tube 12 near the connection 12T with the sealed tube 13A. The metal film 40 on the outer surface of the sealed tube 13A functions as a heat-retaining film that maintains the temperature of the sealed tube 13A within an appropriate range during lighting. The metal film 40 on the outer surface of the discharge tube 12 functions as a heat-retaining film that maintains the coldest spot temperature high during lighting. The formation of such a metal film 40 can prevent mercury vapor from entering the sealed tube 13A and condensing during lighting.

[0029] Here, the metal film 40 provided on the outer surfaces of the sealed tube 13A and the discharge tube 12 is formed by applying a metal film liquid of gold, platinum, etc. Note that a metal film is also formed similarly on the base part of the anode side of the discharge tube 12 or on the sealed tube 13B.

[0030] 2, the metal film 40 formed around the outer surface of the sealed tube 13A is electrically connected to the base 19A by a metal wire 50. Specifically, the metal wire 50 is wound around the metal film 40, extends along the lamp axis C, and has one end attached to a hole (not shown) formed in the discharge tube side end 19T of the base 19A. Here, the metal wire 50 is wound around the metal film 40 one revolution and secured in a ring shape.

[0031] The metal wire 50 is made of a metal that is resistant to heat generated when the lamp is turned on. Here, the metal wire 50 is made of Kanthal wire, but it may be made of SUS or the like.

[0032] The metal wire 50 is connected to the base 19A while being in contact with platinum 60 (metal member). Specifically, a part 62 of the platinum 60 (hereinafter referred to as the wound part) is wound around a straight portion 52 of the metal wire 50 extending along the lamp axis C.

[0033] Here, the platinum 60 is wound around the metal film 40 and secured in a ring shape, similar to the metal wire 50. The wound portion 62 of the platinum 60 is formed in a spiral shape along the lamp axis C so as to be in close contact with the metal wire 50.

[0034] In this way, the electrical connection between the metal film 40 and the base 19A by the metal wire 50 and the contact (wrapping) of the platinum 60 around the metal wire 50 reduces the potential difference between the metal film 40 and the base 19A side (cathode 20). In particular, the platinum 60 reduces the resistance between the metal film 40 and the base 19A, bringing them closer to the same potential. As a result, the migration of alkali metal ions to the metal foil 16A side during lamp lighting is suppressed, and peeling of the metal foil 16A can be prevented.

[0035] Platinum 60 has a lower resistance than metal wire 50 made of Kanthal wire or the like. Therefore, it is easy to reduce the potential difference between metal film 40 and base 19A (cathode 20), and peeling of metal foil 16A caused by alkali metal ions can be suppressed. In addition, because platinum 60 is wound around metal wire 50, it is possible to prevent platinum 60 from loosening and coming into contact with sealing tube 13A, causing devitrification.

[0036] It should be noted that a metal member other than platinum 60 may be used, provided that the metal member has a lower resistance than the metal wire 50 made of Kanthal wire or the like. It is also possible to use a metal wire that partially uses platinum 60, and it is also possible to use a non-linear metal (plate or foil). On the other hand, it is also possible to use a metal made of the same material as the metal wire 50.

[0037] The short arc type discharge lamp described above can be manufactured, for example, as follows: That is, the lamp can be manufactured so that the lamp manufacturing process includes a step of applying a metal film liquid to the outer surface of at least one of the sealed tubes connected to both sides of the discharge tube, and a step of electrically connecting the metal film and the base provided on the sealed tube on which the metal film is formed by a metal wire such as Kanthal wire, and contacting (for example, winding) a metal wire such as platinum with the metal wire such as Kanthal wire.

[0038] In this embodiment, the metal wire 50 and a part of the platinum 60 are wound around the metal film 40 and secured in a ring shape. If the contact between this ring portion and the metal film 40 is insufficient, the electrical connection between the metal film 40 and the cathode side becomes unreliable.

[0039] Therefore, it is possible to manufacture the lamp by winding the metal wire 50 and a portion of the platinum 60 around the sealing tube, and then further including a step of applying a metal film liquid thereon.

[0040] Fig. 3 is a diagram showing a modification of the short arc type discharge lamp of the present embodiment described in Fig. 1 and 2. Here, platinum 60 is wound only around the straight portion 52 of the metal wire 50. With such a configuration, the resistance between the metal film 40 and the base 19A is reduced, and peeling of the metal foil can be suppressed.

[0041] 4 is a diagram showing another modified example of the short arc type discharge lamp of this embodiment. In this example, a plurality of metal wires (two in FIG. 4) 50 and a plurality of platinum wires 60 (two in FIG. 4) are prepared and wound around a metal film 40 in a ring shape.

[0042] The multiple metal wires 50 and platinum 60 are in contact with each other at the portion wound into a ring shape, while extending separately along the lamp axis C and connecting to the base 19A. This configuration also reduces the resistance between the metal film 40 and the base 19A, and prevents the metal foil from peeling off. A single metal wire 50 may be attached so as to go back and forth between the metal film 40 and the base 19A.

[0043] The above-mentioned configuration of the metal wire 50 and platinum 60 can also be applied to the sealing tube 13B on the anode side. EXAMPLES

[0044] The following describes an embodiment. The short arc type discharge lamp of this embodiment is a discharge lamp corresponding to the short arc type discharge lamp of the present embodiment shown in Fig. 1 and Fig. 2, in which a rare gas (xenon) is sealed in the discharge space DS and an arc discharge occurs with a predetermined rated power (12 kW in this embodiment).

[0045] Kanthal wire (manufactured by Sakaguchi Electric Heating Co., Ltd.) was used as the metal wire, and platinum (manufactured by Nilaco Co., Ltd.) was wound around the metal wire. In the lamp manufacturing process, the metal wire and platinum were wound around the metal film applied to the sealing tube, and then another metal film was applied from above.

[0046] On the other hand, a short arc type discharge lamp as a comparative example was prepared using a Kanthal wire as the metal wire and not including platinum (hereinafter, referred to as the comparative example). The comparative example has substantially the same configuration as the short arc type discharge lamp of this embodiment, except for the configuration not including platinum.

[0047] The resistance value of the short arc type discharge lamp of this embodiment was measured to be 0.65Ω. On the other hand, the resistance value of the short arc type discharge lamp of the comparative example was measured to be 1.33Ω. The resistance value was measured at the metal film and base using a tester (manufactured by Kaise Co., Ltd.).

[0048] The short arc type discharge lamp of this embodiment and the short arc type discharge lamp of the comparative example were lit at 12 kW for 150 hours, and an experiment was carried out to confirm peeling of the metal foil.

[0049] In the comparative example, 8 mm of the metal foil peeled off after 150 hours of lighting, whereas in this example, 1.6 mm of the metal foil peeled off, confirming the effect of this example in preventing metal foil peeling. [Explanation of symbols]

[0050] 10. Short arc type discharge lamps 13A sealed tube 19A Base 40 Metal Film 50 Metal Wire 60 Platinum (metallic parts)

Claims

1. A discharge tube in which a pair of electrodes are disposed opposite each other; a sealing tube provided on both sides of the discharge tube; A metal film formed on an outer surface of at least one of the sealing tubes; a metal wire electrically connecting the metal film and at least one of the electrodes; a metal member that contacts at least a part of the metal wire around the sealing tube on which the metal film is formed; A short arc type discharge lamp comprising:

2. 2. The short arc type discharge lamp according to claim 1, wherein the metal member has a linear winding portion that is wound around the metal wire.

3. 2. The short arc type discharge lamp according to claim 1, wherein the metal member has a linearly wound portion wound around the metal film.

4. 4. The short arc type discharge lamp according to claim 3, wherein the metal film includes a metal film formed on the wound portion.

5. 2. The short arc type discharge lamp according to claim 1, wherein the metal member has a lower resistance than the metal wire at least in a portion in contact with the metal wire.

6. 2. The short arc type discharge lamp according to claim 1, wherein said metal member at least partially comprises platinum.

7. 2. The short arc type discharge lamp according to claim 1, wherein the metal member is made of the same material as the metal wire.

8. 2. The short arc type discharge lamp according to claim 1, wherein a plurality of said metal wires and said metal members are provided.

9. 2. The short arc type discharge lamp according to claim 1, wherein the metal wire is connected to a base provided on a sealing tube on which the metal film is formed.

10. forming a metal film on an outer surface of at least one of the sealed tubes connected to both sides of the discharge tube; The metal film is electrically connected to a base provided on the sealing tube on which the metal film is formed by a metal wire; A linear metal member is brought into contact with the metal wire.

4. A method for manufacturing a short arc type discharge lamp comprising the steps of:

11. 11. The method for manufacturing a short arc type discharge lamp according to claim 10, further comprising forming a metal film on the metal member wound around the metal film.

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