Discharge lamp and method for manufacturing the same

Abstract

A discharge lamp and a method for manufacturing the same are provided. A discharge lamp having a sealing structure with excellent thermal durability is provided. An electrode support rod (22A) is inserted through a sealing tube (20) of the discharge lamp (10), and an inner metal ring (26) connected to a metal foil (36) on the outer peripheral surface is assembled into a mounting component (18A). The inner metal ring (26) is composed of a disk portion (26B) and an extension portion (26C) gradually extending from the periphery thereof, and is formed into a bowl shape.

Description

Technical Field

[0001] The present invention relates to a discharge lamp, and more particularly to a sealing structure of a sealing tube provided with an electrode mounting component. Background Art

[0002] In large short arc discharge lamps (for example, 1 kW or more), the power is being increased to improve the production efficiency of semiconductor and liquid crystal manufacturing. As the power is increased, the electrodes are also increased in size, and therefore the sealing tube in which the mounting parts are arranged is also increased in size.

[0003] In this discharge lamp mounting component, a metal ring is fixed to an electrode support rod held by a cylindrical glass tube, and a plurality of strip-shaped metal foils are welded to the outer circumference of the metal ring. Thus, power is supplied to the electrodes in the light-emitting tube via the metal foil, the metal ring, and the electrode support rod.

[0004] During the lighting of the lamp, due to the difference in thermal expansion between the metal parts and the sealing tube, cracks are likely to occur in the sealing tube near the metal ring and the strip metal foil. In order to prevent this, for example, the thickness of the strip metal foil is set to a specific thickness to satisfy a predetermined conditional expression (see Patent Document 1).

[0005] Prior art literature

[0006] Patent Document 1: Japanese Patent No. 6371275 Summary of the invention

[0007] In order to increase the size of the exposure object and improve the throughput, the discharge lamp is required to have a higher output. In addition, in order to achieve precise exposure, the current flowing when the lamp is lit is high, and the sealed tube is subjected to greater thermal influence. In such a discharge lamp, it is difficult to suppress the generation of cracks by simply adjusting the thickness of the metal foil.

[0008] Therefore, there is a demand for a sealing structure of a sealing tube having excellent thermal durability in a discharge lamp.

[0009] The discharge lamp of the present invention comprises: an electrode support rod, which supports the electrode in the light-emitting tube and is arranged in a sealed tube connected to the light-emitting tube as a whole; a glass tube, the electrode support rod is inserted through the glass tube, and the glass tube is welded to the sealed tube; and a metal component, which electrically connects the metal foil arranged along the electrode axis to the electrode support rod. For example, the sealed tube can be composed of a plurality of sealed tubes such as a double sealed tube.

[0010] Furthermore, the metal component has a disk portion and an extension portion extending from at least a portion of the periphery of the disk portion toward the arc tube side, and the extension portion extends in a direction away from the electrode support rod relative to the electrode axis. Here, it is sufficient that at least a portion of the extension portion extends in a direction away from the electrode axis, and the direction extending from the periphery of the disk portion can be configured to be a direction inclined relative to the electrode axis, and can also be configured to extend straight from the periphery and be inclined at the end.

[0011] The entire extension portion may extend in the same direction, or may extend at a different angle on the end side. For example, the extension portion may be configured to form a conical surface, and may also form a conical surface and a cylindrical surface, with a straight portion extending parallel to the electrode axis on the end side. The extension portion may be inclined relative to the electrode axis within a range of 0°<θ≤15°.

[0012] The end of the extension part can be configured to face the glass tube so as not to affect the sealing tube by thermal expansion. For example, the glass tube can be provided with a step portion at the end facing the metal member, so that the end of the extension part can face the step portion. A gap that receives the thermal expansion of the extension part can be formed in at least a portion of the periphery of the extension part (particularly on the side of the end face of the extension part facing the glass tube).

[0013] When a foil component covering the metal foil and the metal component is provided, since the extension is covered by the foil component, the end of the foil component on the glass tube side can be located closer to the glass tube side than the end of the extension. A disc foil can be provided, which is arranged between the glass tube and the metal component and has a shape corresponding to the metal component.

[0014] A discharge lamp according to another aspect of the present invention comprises: an electrode support rod, which supports the electrode in the light-emitting tube and is arranged in a sealed tube integrally connected to the light-emitting tube; a glass tube, through which the electrode support rod is inserted, and the glass tube is welded to the sealed tube; and a metal component, which electrically connects a metal foil arranged along the electrode axis to the electrode support rod, the metal component comprising a disk portion and an extension portion extending from at least a portion of the periphery of the disk portion toward the light-emitting tube side, the extension portion extending from the periphery along the electrode axis, and an end portion thereof being opposite to the glass tube.

[0015] The metal component of other aspects of the present invention is sealed in a sealed tube of a discharge lamp and is arranged coaxially with an electrode support rod disposed in the sealed tube. The metal component comprises: a disc portion; and an extension portion, which is provided with an inclined portion that gradually extends from the periphery of the disc portion toward at least one side surface of the disc portion to form a conical surface.

[0016] The manufacturing method of the discharge lamp according to another aspect of the present invention comprises the following steps: processing a disk-shaped metal material to form a metal component having a shape including a conical surface gradually expanding from its periphery, and forming the metal component into a bowl shape; welding an electrode support rod to the metal component; and inserting a mounting component including the metal component into a sealing tube and sealing it.

[0017] According to the present invention, it is possible to provide a discharge lamp having a sealing structure excellent in thermal durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic structural diagram of the short arc discharge lamp of this embodiment.

[0019] Figure 2 It is a cross-sectional view of the sealing tube on the cathode side.

[0020] Figure 3 This is a schematic cross-sectional view of the sealing tube near the metal parts.

[0021] Figure 4 It is a cross-sectional view of a metal component.

[0022] Figure 5 It is a diagram showing a metal component according to a modified example of the present embodiment.

[0023] Figure 6 It is a diagram showing a metal component according to a second modified example of the present embodiment.

[0024] Figure 7 FIG. 1 is a diagram showing a graph indicating the degree of reduction in stress applied to a sealing tube.

[0025] Description of labels:

[0026] 10 Discharge lamp

[0027] 20 Sealing tube

[0028] 22A Electrode support rod

[0029] 24 Glass Tube

[0030] 26 Inner metal ring (metal part)

[0031] 26B Disc

[0032] 26C Extension DETAILED DESCRIPTION

[0033] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0034] Figure 1 It is a schematic structural diagram of the short arc discharge lamp of this embodiment.

[0035] The short arc discharge lamp 10 is a discharge lamp in which an anode 14 and a cathode 16 are arranged opposite to each other in a light emitting tube 12 made of quartz glass. Quartz glass sealing tubes 20 and 60 are integrally formed at both ends of the light emitting tube 12 so as to face each other.

[0036] Parts (hereinafter referred to as mounting components) 18A and 18B that support the cathode 16 and the anode 14 and seal the discharge space 11 in the light-emitting tube 12 are sealed inside the sealing tubes 20 and 60, respectively. Both ends of the sealing tubes 20 and 60 are blocked by metal seals 80A and 80B. Mercury and rare gas are sealed in the discharge space 11, and the amount of mercury is determined so that light is emitted at a rated power of 1 kW or more.

[0037] Figure 2 yes Figure 1 18A of the cathode side. The metal seal 80A is omitted here. The anode side mounting member 18B has the same structure.

[0038] The sealing tube 20 has a double tube sealing structure and is composed of an inner sealing tube 20A and an outer sealing tube 20B, and the inner sealing tube 20A and the outer sealing tube 20B are welded to each other. The mounting member 18A has a cylindrical thick-walled glass tube (hereinafter referred to as a glass tube) 24, a columnar glass member 34, and a plurality of strip-shaped metal foils 36. The inner sealing tube 20A is welded to the glass tube 24 and the glass member 34.

[0039] A conductive electrode support rod 22A supporting the cathode 16 is arranged along the electrode axis E (lamp axis) in the sealed tube 20. The electrode support rod 22A is inserted through an axial hole 24A formed in the glass tube 24 and is held by the glass tube 24.

[0040] On the other hand, on the sealing tube end side (metal seal 80A side), a conductive lead rod 28 is arranged so as to face the electrode support rod 22A. The electrode support rod 22A and the lead rod 28 are axially inserted into holes (recessed portions) 34A and 34B provided at both ends of the glass member 34, respectively, and the glass member 34 holds the electrode support rod 22A and the lead rod 28. The lead rod 28 is connected to an external lead wire (not shown) connected to a power supply unit (not shown).

[0041] Metal rings (metal parts) 26 and 32 are respectively arranged at both ends of the glass part 34, and the electrode support rod 22A and the lead rod 28 are respectively welded to the axial holes 26A and 32A of the metal rings 26 and 32, and are all arranged coaxially with respect to the electrode axis E. The metal rings 26 and 32 can be made of any conductive metal material (for example, tungsten, molybdenum, tantalum, etc.).

[0042] The metal ring (hereinafter referred to as the inner metal ring) 26 near the arc tube 12 is sandwiched by disc foils 42 and 44, which are disk-shaped and have holes through which the electrode support rod 22A is inserted, and the other metal ring (hereinafter referred to as the outer metal ring) 32 is similarly sandwiched by disc foils 52 and 54. A thick-walled fixed glass tube 50 is fixed to the end side of the sealing tube, through which the lead rod 28 is inserted and held.

[0043] Between the inner metal ring 26 and the outer metal ring 32, a plurality of strip-shaped metal foils (e.g., molybdenum foils) 36 extend along the outer surface of the glass member 34 and along the electrode axis E, and both ends thereof are welded to the outer peripheral surfaces of the inner metal ring 26 and the outer metal ring 32. The outer metal ring 32 electrically connects the lead rod 28 to the metal foil 36, and the inner metal ring 26 electrically connects the metal foil 36 to the electrode support rod 22A.

[0044] Figure 3 It is a schematic cross-sectional view of the sealing tube 20 near the inner metal ring 26 . Figure 4 It is a cross-sectional view of the inner metal ring 26 .

[0045] The inner metal ring 26 has a disk portion 26B with flat sides as a base portion, and a ring-shaped extension portion 26C extending from the periphery of the disk portion 26B toward the arc tube side. The extension portion 26C forms a conical surface 26S3 that gradually expands toward the arc tube side, and when viewed from the arc tube side, the inner metal ring 26 is formed into a bowl shape with one side surface 26S2 as the bottom surface.

[0046] like Figure 4 As shown, the extension portion 26C is inclined at an angle θ relative to the electrode axis E in a direction away from the electrode support rod 22A, that is, toward the outside of the sealed tube. Here, the angle θ is determined to be in the range of 0°<θ≤15°. The end surface 26S4 of the end portion 26D of the extension portion 26C is parallel to the disc portion 26B.

[0047] The glass tube 24 has a shape formed by connecting a cylindrical small diameter portion 24D1, a middle diameter portion 24D2, and a large diameter portion 24D3 having diameters D1, D2, and D3 of different sizes, respectively, and step portions J1 and J2 are formed between the small diameter portion 24D1 and the middle diameter portion 24D2, and between the middle diameter portion 24D2 and the large diameter portion 24D3, respectively.

[0048] The end surface 26S4 of the extension portion 26C of the inner metal ring 26 is located at a position opposite to the step portion J1 and opposite to the middle diameter portion 24D2. In addition, a gap KS having a distance interval B along the electrode axis E is provided between the end surface 26S4 of the extension portion 26C and the middle diameter portion 24D2. The strip-shaped metal foil 36 extends to the extension portion 26C of the metal ring 26 and does not contact the step portion J1, that is, the glass tube 24.

[0049] The step portion J2 is welded to the inner sealing tube 20A and is in contact with the rolled foil (foil member) 39. The rolled foil 39 is made of a foil made of Mo or Ta and extends from the vicinity of the inner metal ring 26 of the glass member 34 to the step portion J2 of the glass tube 24 in the electrode axis direction, covering the glass member 34, the inner metal ring 26, and the small diameter portion 24D1 and the middle diameter portion 24D2 of the glass tube 24. Figure 1 , 2 The foil coil 39 is not shown.

[0050] The disc foil 42 in contact with the arc tube side surface 26S2 of the inner metal ring 26 is formed in the same bowl shape as the inner metal ring 26, and forms a conical surface by the gradually expanding extension portion, so as to contact across both the disc portion 26B and the extension portion 26C of the inner metal member 26. Therefore, the inner metal ring 26 does not contact the small diameter portion 24D1 of the glass tube 24.

[0051] By introducing such an inner metal ring 26 , it is possible to suppress the occurrence of cracks in the sealing tube during the lighting of the lamp as described below.

[0052] During the lighting process of the lamp, the inner metal ring 26 thermally expands, and not only the disk portion 26B, but also the extension portion 26C extending in the direction close to the electrode axis will thermally expand. The direction of thermal expansion is dispersed in the radial direction and the inclined direction of the extension portion 26C, so that the radial stress on the coil foil 39 and the sealing tube 20 is reduced (stress is not concentrated in one direction), and the generation of cracks can be suppressed. In particular, by setting the inclination angle θ to be less than 15°, the stress can be effectively suppressed.

[0053] Furthermore, since the extension portion 26C extends toward the arc tube side, the metal foil 36 also thermally expands (is stretched) in the direction of thermal expansion of the extension portion 26C, and distortion and wrinkling of the metal foil 36 can be prevented.

[0054] On the other hand, a gap KS is formed between the end 26D of the extension 26C and the glass tube 24, so when the extension 26C is thermally expanded, stress is not applied to the glass tube 24 and the sealing tube 20, and crack generation can be suppressed. The gap KS is determined by the distance between the small diameter portion 24D1 of the glass tube 24 and the end surface 26S4 of the extension 26C, so the gap KS can be determined to a desired length in the electrode axis direction by adjusting the length of the small diameter portion 24D1 in the electrode axis direction, that is, determining the shape of the step portion J1. In addition, since the end 26D of the extension 26C is arranged opposite to the glass tube 24, the sealing operation can be performed stably.

[0055] Furthermore, the foil 39 covering the glass member 34 extends beyond the end 26D of the extension portion 26C and until it contacts the glass tube 24, and the foil 39 covers the gap KS and is exposed in the gap KS. Thus, when the extension portion 26C thermally expands during the lighting of the lamp, the deformation of the foil 39 can also absorb stress, so the occurrence of cracks can be further suppressed.

[0056] The disk foil 42 disposed between the inner metal ring 26 and the glass tube 24 is formed in a bowl shape corresponding to the shape of the inner metal ring 26. Thus, the extension portion 26C does not come into direct contact with the glass tube 24, and the occurrence of cracks in the glass tube 24 can be suppressed.

[0057] A discharge lamp having such a sealing structure can be manufactured according to the following manufacturing method. That is, a hole for inserting an electrode support rod is formed into a disc-shaped metal material, and further, the metal material is processed by stamping or the like to form a conical surface that gradually expands from the periphery of the metal material, thereby forming a bowl-shaped metal component. Furthermore, the electrode support rod is inserted into the metal component and welded, and a strip of metal foil is welded to the outer peripheral surface of the metal component to assemble the mounting component. After the mounting component is inserted into the sealing tube, the sealing tube is reduced in diameter by heat to seal the mounting component. Thus, a discharge lamp is manufactured. In addition, the assembly sequence of the discharge lamp is not limited to the above sequence. For example, the hole for inserting the electrode support rod can be formed after the metal material is stamped, and the metal material can be formed into a bowl shape after the electrode support rod is inserted. In addition, in addition to stamping, the component corresponding to the extension portion can be welded, or the metal material that is already in a bowl shape can be cut and formed.

[0058] In the discharge lamp 10 of the present embodiment, a step portion is formed on the glass tube, but a structure of a glass tube without a step portion may also be adopted. In addition, the foil roll may also adopt a structure covered like a cover, or a structure without a foil roll may also be adopted. In the present embodiment, a double sealed tube is adopted for use in a large discharge lamp, but a sealed tube structure based on a single tube other than the double sealed tube may also be adopted. In addition, a structure in which a disc foil is not provided on the side of the inner metal ring may also be adopted.

[0059] Regarding the inner metal ring 26, the length of the extension portion along the electrode axis direction is arbitrary, as long as it is set to be shorter than the diameter of the disk portion and longer than the thickness of the inner metal ring 26. In addition, the angle R ( Figure 4 ) Set the rounded corners and set the curvature radius to 0.3~5.

[0060] The extension portion 26C extends from the entire periphery of the disk portion 26B to form a conical surface, but may also be configured to extend from a portion of the periphery (e.g., at a predetermined interval). In addition, only one electrode-side sealing tube may be used for the inner metal ring 26, and the outer metal ring connected to the lead rod may also adopt the same structure.

[0061] Regarding the shape of the inner metal ring, in addition to the extended portion forming the conical surface, an extended portion further extending in the axial direction may be provided to form a cylindrical surface.

[0062] Figure 5 It is a diagram showing an inner metal ring according to a first modified example of the present embodiment.

[0063] The inner metal ring 260 has an extension portion 260C extending from the periphery of the disk portion 260B having the hole 260A toward the arc tube. The extension portion 260C is composed of an inclined portion 260C1 forming a conical surface and a straight portion 260C2 extending along the electrode axis E to form a cylindrical surface.

[0064] By providing the straight portion 260C2 at the end side of the extension portion 260C, even when thermally expanded, the extension portion 260C expands in the gap KS toward the step portion J1, thereby further suppressing cracks. In addition, by providing the straight portion 260C2, welding with the metal foil 36 is facilitated. In addition, the extension portion 260C may be composed of only the straight portion 260C2, or the inclined portion 260C1 may be formed at the end side of the extension portion 260C.

[0065] The shape of the inner metal ring is not limited to a bowl shape that gradually extends from one side toward the arc tube side, and an extension portion that extends toward the opposite side may be provided.

[0066] Figure 6 360 is a diagram showing an inner metal ring of a second modified example of the present embodiment. The inner metal ring 360 is formed with a disk portion 360B having a hole 360A, and extension portions 360C1 and 360C2 extending gradually from the periphery of the disk portion 360B in two directions of the side. Thus, the extension portions 360C1 and 360C2 are thermally expanded in the inclined direction, and the same effect as the inner metal ring 26 can be obtained.

[0067] [Example]

[0068] The discharge lamp of this embodiment is obtained by modeling the discharge lamp corresponding to the embodiment on a computer, reproducing the structure of the glass tube and the foil with the step portion, which is equivalent to the double sealed tube. Hereinafter, the lighting simulation is performed according to the prescribed lighting conditions while changing the inclination angle of the extension portion, and the degree of reduction of the stress on the sealed tube is investigated. Among them, the simulation is performed under the condition of supplying 8kW of power and stably lighting.

[0069] Figure 7 1 is a graph showing a relationship between the inclination angle of the extension and the degree of reduction of the stress on the sealed tube. In the comparative example, a discharge lamp composed of a conventional disc-shaped inner metal ring without an extension is modeled. The structure other than the inner metal ring is the same as that of the embodiment. The vertical axis shows the ratio of the stress values ​​when the inclination angle of the embodiment is changed while the stress value of the comparative example is set to 1. The lower the value, the lower the possibility of damage to the sealed tube.

[0070] Depend on Figure 7 It can be seen that the value decreases as the inclination angle θ increases. It is the lowest at 10°, and the value does not decrease thereafter. That is, the stress can be effectively suppressed by setting the inclination angle θ to 15° or less. In addition, since the value decreases even when the inclination angle is 0°, even if the extension portion is formed only by the straight line portion shown in the first modification, it is effective.

Claims

1. A discharge lamp, characterized in that The discharge lamp has: An electrode support rod, which supports the electrode in the light-emitting tube and is disposed in a sealed tube integrally connected to the light-emitting tube; a glass tube, the electrode support rod is inserted through the glass tube, and the glass tube is welded to the sealing tube; and a metal member that electrically connects the metal foil disposed along the electrode axis to the electrode support rod, supplying electric power to the electrodes in the arc tube via the metal foil, the metal member and the electrode support rod, The metal component has a disk portion and an extension portion extending from at least a portion of a periphery of the disk portion toward the arc tube side. The extension portion extends in a direction away from the electrode support rod relative to the electrode axial direction.

2. The discharge lamp according to claim 1, characterized in that The extension portion forms a conical surface.

3. The discharge lamp according to claim 1 or 2, characterized in that The extension portion forms a conical surface and a cylindrical surface.

4. The discharge lamp according to claim 1 or 2, characterized in that The extending portion is inclined relative to the electrode axis within a range of 0°<θ≤15°.

5. The discharge lamp according to claim 1 or 2, characterized in that An end portion of the extending portion is opposed to the glass tube.

6. The discharge lamp according to claim 1 or 2, characterized in that A gap is formed around at least a portion of the extension portion.

7. The discharge lamp according to claim 1 or 2, characterized in that The glass tube has a stepped portion at an end portion opposite to the metal component. An end of the extending portion is opposite to the step portion.

8. The discharge lamp according to claim 1 or 2, characterized in that The discharge lamp further includes a foil member covering the metal foil and the metal member. An end portion of the foil member on the glass tube side is located closer to the glass tube side than an end portion of the extending portion.

9. The discharge lamp according to claim 1 or 2, characterized in that The discharge lamp further includes a disc foil that is disposed between the glass tube and the metal member and has a shape corresponding to the metal member.

10. The discharge lamp according to claim 1 or 2, characterized in that The sealing tube is composed of a plurality of sealing tubes.

11. A metal component, the metal component being sealed in a sealing tube integrally connected to a light-emitting tube of a discharge lamp, and being coaxially arranged with an electrode supporting rod supporting an electrode in the light-emitting tube of the discharge lamp and provided in the sealing tube, characterized in that: The metal component electrically connects a metal foil disposed along the electrode axis of the discharge lamp to the electrode support rod, and supplies power to the electrode in the arc tube via the metal foil, the metal component and the electrode support rod. The metal component has: disc; as well as The extension portion is provided with an inclined portion which gradually extends from the periphery of the disc portion toward at least one side surface of the disc portion to form a conical surface.

12. A discharge lamp, characterized in that: have: An electrode support rod, which supports the electrode in the light-emitting tube and is disposed in a sealed tube integrally connected to the light-emitting tube; a glass tube, the electrode support rod is inserted through the glass tube, and the glass tube is welded to the sealing tube; and a metal member that electrically connects the metal foil disposed along the electrode axis to the electrode support rod, supplying electric power to the electrodes in the arc tube via the metal foil, the metal member and the electrode support rod, The metal component has a disk portion and an extension portion extending from at least a portion of a periphery of the disk portion toward the arc tube side. The extension portion extends from the periphery along the electrode axis, and an end portion thereof faces the glass tube.

13. A method for manufacturing a discharge lamp according to claim 1 or 12, characterized in that: The manufacturing method of the discharge lamp comprises the following steps: Processing a disk-shaped metal material to form a shape including a conical surface gradually expanding from its periphery, thereby forming a bowl-shaped metal part; welding the electrode support rod to the metal component; and The mounting component including the metal component is inserted into the sealing tube and sealed.

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