Discharge lamp and method for manufacturing discharge lamp

Abstract

A discharge lamp and a method for manufacturing the discharge lamp are provided. In a short arc type discharge lamp or the like, a mounting component is sealed without generating wrinkles or the like on a metal foil. In a discharge lamp (10) obtained by arranging a plurality of metal foils (36) on the outer surface of a columnar glass component (34) along the lamp axis direction and welding the metal foils (36) to the outer peripheral surface (26S) of an inner metal ring (26) connected to an electrode support rod (22), an annular crimping component (50) presses the metal foil (36) on and near the outer peripheral surface (26S) of the inner metal ring (26) toward the center side of the inner metal ring (glass component), thereby fastening the metal foil (36).

Description

Technical Field

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

[0002] In a short arc type discharge lamp, a glass sealing tube is integrally formed at both ends of a light-emitting tube that seals the electrode, and a mounting component is sealed in the sealing tube. In the mounting component, an electrode support rod is inserted through a cylindrical glass tube and is held by the glass tube. In addition, a metal foil is arranged along the surface of the columnar glass component (glass rod), and power is supplied to the electrode side through the metal foil. In a discharge lamp with a large power, an annular component such as a metal ring is fixed to the electrode support rod, and a plurality of metal foils are welded to the outer peripheral surface of the annular component (see Patent Document 1).

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2009-238671 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] The metal foil is hard and difficult to bend in the width direction. Therefore, when the metal foil is welded to the annular component, the two edges of the foil along the axial direction will not follow the outer surface of the glass component, but will float from the surface. When the mounting component is sealed in this state, that is, when the glass sealing tube is welded to the glass component, the metal foil will wrinkle and kink. The wrinkles and kinks may cause cracks in the sealed part.

[0008] Therefore, in a short arc discharge lamp or the like, a technology for sealing a mounting component without causing wrinkles or the like in the metal foil is required.

[0009] Means used to solve problems

[0010] The discharge lamp of the present invention comprises: a columnar glass component, which is arranged in a sealed tube formed integrally with the light-emitting tube and fused to the sealed tube; a plurality of metal foils, which extend along the lamp axis direction between the sealed tube and the glass component; a conductive annular component, which contacts the plurality of metal foils on the outer peripheral surface and is connected to an electrode support rod arranged along the lamp axis; and an annular crimping component, which presses the plurality of metal foils on the outer peripheral surface of the annular component so that the plurality of metal foils are along the surface of the glass component at least near the annular component.

[0011] The crimping component may be composed of a component that presses the metal foil on the outer peripheral surface of the annular component. For example, the crimping component may be composed of a component that is tightly wound in a manner that tightens, binds, or presses the metal foil in the entire circumferential range. In addition, the crimping component may have a concave-convex portion that contacts the metal foil near at least two edges of the metal foil. For example, the crimping component is made of metal and is welded to the metal foil.

[0012] When appropriate pressure bonding is considered, the axial length of the region where the pressure-bonding component presses the metal foil on the surface of the glass component is in the range of 0.5 to 2.0 times the axial length of the annular component. In addition, the pressure-bonding component may be configured to have an overlapping portion at a position facing the predetermined metal foil.

[0013] On the other hand, when the metal foil is arranged along the surface of the glass member, the width of the metal foil along the circumferential direction can be determined to satisfy the following formula:

[0014] L / 2×sin(90L / πD)≦1.2

[0015] Here, D (mm) represents the diameter of the glass member, and L (mm) represents the width of the metal foil, and may be, in particular, 1.00 mm or less, 0.8 mm or less, or the like.

[0016] In a method for manufacturing a discharge lamp according to one embodiment of the present invention, a plurality of metal foils are arranged in a circumferential direction along the surface of a columnar glass component; the metal foils are welded to the outer circumferential surface of a conductive annular component in contact with an electrode support rod; and an annular metal crimping component is welded to the plurality of metal foils on the outer circumferential surface of the annular component so that the plurality of metal foils are along the surface of the glass component at least near the annular component. The crimping component presses the metal foil toward the outer circumferential surface of the annular component, and the metal foil is deformed to be along the surface of the glass component at least near the annular component in a stage before the mounting component is fused to the sealing tube.

[0017] A method for manufacturing a discharge lamp according to one embodiment of the present invention comprises the following steps: preparing a plurality of metal foils having a floating height of 1.2 mm or less when in contact with a columnar glass component of a mounting component; welding the metal foils to the outer peripheral surface of a conductive annular component of the mounting component; and welding an annular metal crimping component to the plurality of metal foils on the outer peripheral surface of the annular component. Here, "floating height" refers to the distance in the vertical direction between the edge of the metal foil and the surface of the glass component when the center of the width direction of the flat metal foil is in contact with the glass component. By making the floating height less than 1.2 mm, the edge of the metal foil is close to or in contact with the surface of the glass component at the stage before the mounting component and the sealing tube are fused.

[0018] Effects of the Invention

[0019] According to the present invention, in a short arc type discharge lamp or the like, a mounting component can be sealed without causing wrinkles or the like in the metal foil. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic cross-sectional view of the short arc discharge lamp according to the present embodiment.

[0021] Figure 2 It is a top view of the mounting component showing the arrangement of the metal foil and the crimping component.

[0022] Figure 3 This is a diagram showing one sheet of metal foil before welding of the crimping component.

[0023] Figure 4 To show Figure 1 A cross-sectional view of a portion near an end portion of a metal foil.

[0024] Figure 5 This is a diagram showing the relationship between the width of the metal foil, the floating height, and the diameter of the glass member.

[0025] Figure 6 It is a cross-sectional view along the inner metal ring before the crimping component is welded to the metal foil.

[0026] Description of symbols

[0027] 10 Discharge lamp

[0028] 20 Sealing tube

[0029] 26 Inner metal ring (ring-shaped part)

[0030] 34 Glass Parts

[0031] 36 metal foil

[0032] 50 Crimp parts DETAILED DESCRIPTION

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

[0034] Figure 1 It is a schematic cross-sectional view of the short arc discharge lamp according to the present 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 quartz glass arc tube 12. Quartz glass sealing tubes 20 and 60 are integrally formed to face each other at both ends of the arc tube 12. Both ends of the sealing tubes 20 and 60 are closed by caps 80A and 80B.

[0036] Components (hereinafter referred to as mounting components) 18A and 18B are sealed inside the sealed tubes 20 and 60, respectively, and they support the anode 14 and the cathode 16 and seal the discharge space 11 in the arc tube 12. The mounting component 18A includes a cylindrical thick-walled glass tube (hereinafter referred to as a glass tube) 24, a columnar glass component 34, and a plurality of metal foils 36. The mounting component 18B also has the same structure. Mercury and a rare gas are sealed in the discharge space 11.

[0037] A conductive electrode support rod 22 supporting the anode 14 is arranged along the electrode axis E (sealed tube axis) in the sealed tube 20. The electrode support rod 22 is inserted through an axial hole 24A formed in the glass tube 24 and is held by the glass tube 24.

[0038] On the other hand, on the end side of the sealed tube, a conductive lead rod 28 is arranged so as to face the electrode support rod 22. The electrode support rod 22 and the lead rod 28 are axially inserted into holes (recessed portions) 34A and 34B provided at both ends of a glass member 34, and the glass member 34 holds the electrode support rod 22 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).

[0039] Metal rings (ring-shaped members) 26 and 32 are respectively arranged at both ends of the glass member 34, and the electrode support rod 22 and the guide rod 28 are welded to the axial holes 26A and 32A of the metal rings 26 and 32. The metal ring (hereinafter referred to as the inner metal ring) 26 close to the arc tube 12 is sandwiched by disc-shaped circular foils 42 and 44, and the other metal ring (hereinafter referred to as the outer metal ring) 32 is also sandwiched by disc-shaped circular foils (here, not shown).

[0040] 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 in the direction of the lamp axis E, and both ends thereof are welded to the outer peripheral surfaces 26S and 32S of the inner metal ring 26 and the outer metal ring 32. The outer metal ring 32 electrically connects the lead rod 28 and the metal foil 36, and the inner metal ring 26 electrically connects the metal foil 36 and the electrode support rod 22. Thus, power is supplied to the anode 14 from the lead rod 28 connected to the power supply unit.

[0041] A metal annular pressing member 50 is provided on the outer peripheral surface 26S of the inner metal ring 26. The annular pressing member 50 presses the metal foil 36 toward the glass member 34 so that the metal foil 36 is along the outer surface of the glass member 34, and the end of the metal foil 36 is fastened to the glass member 34 (inner metal ring 26). That is, the pressing member 50 is not a member that covers the periphery of the glass member 34 and the inner metal ring 26, but is a member that applies force to the metal foil 36 toward the outer surface side of the glass member 34.

[0042] Figure 2 1 is a top view of the mounting component 18A showing the arrangement of the metal foil 36 and the crimping component 50. Here, the mounting component 18A is shown as seen from the axial direction before the sealing tube 20 is sealed. However, the thickness of the metal foil 36 and the crimping component 50 are exaggerated. In addition, the axial edges 36K1 and 36K2 of the metal foil 36 are actually tapered like blades.

[0043] The metal foil 36 is composed of six metal foils having the same width, and is arranged at predetermined intervals in the circumferential direction of the glass member 34. Here, since the six metal foils 36 are arranged symmetrically about the axis E, the metal foils 36 are arranged at equal intervals in the circumferential direction.

[0044] The crimping component 50 has a circumference of approximately one turn of the glass component 34 (inner metal ring 26), and is made of a ring-shaped metal member provided with an overlapping portion 50T. Here, the crimping component 50 is made of metal foil. The crimping component 50 is welded to the metal foil 36 on the outer peripheral surface 26S of the inner metal ring 26.

[0045] Figure 3 1 is a diagram showing a sheet of metal foil 36 before welding the crimping component 50. The metal foil 36 is a flat strip of metal, which is hard and difficult to bend in the width direction. When such a metal foil 36 is placed on the outer surface of the glass component 34, the farther away from the contact portion, the more a gap ΔT (hereinafter referred to as floating height) will be generated between the glass component 34 and the metal foil 36. In addition, the larger the width L of the metal foil 36, the larger the floating height ΔT.

[0046] The crimping member 50 bends the metal foil 36 along the circumferential direction of the glass member 34 at and near the outer peripheral surface 26S of the inner metal ring 26 , and applies force to the metal foil 36 so that the entire width L of the metal foil 36 contacts the glass member 34 .

[0047] Figure 4 To show Figure 1 2 is a cross-sectional view of a portion near the end portion of the metal foil 36 .

[0048] The crimping member 50 has an axial width T, and its two edges 50E1 and 50E2 along the circumferential direction are respectively located on the surfaces of the glass member 34 and the glass tube 24. That is, the crimping member 50 extends in the lamp axis direction across the glass member 34, the inner metal ring 26, and the glass tube 24. Figure 4 In FIG. 1 , the thicknesses of the crimping member 50 , the disk foils 42 , 44 , and the metal foil 36 are exaggerated, and the outer diameters of the glass member 34 , the inner metal ring 26 , and the glass tube 24 can be made substantially the same.

[0049] The axial length J of the region where the metal foil 36 is pressed by the pressing member 50 on the outer surface of the glass member 34 (hereinafter referred to as the pressing length) is set to be in the range of 0.5 to 2.0 times the thickness (axial length) RT of the inner metal ring 26. If it is less than 0.5 times, the metal foil 36 cannot be sufficiently pressed on the surface of the glass member 34, while if it exceeds 2.0 times, the welding area between the glass member 34 and the sealing tube 20 is reduced, which affects the reliability of the sealing structure.

[0050] The back surface of the crimping component 50 has a concavoconvex portion at a position of contact with the end portion 36T of the metal foil 36, especially near the two edges 36K1 and 36K2. Here, the concavoconvex portion is formed on the back surface (and the surface) of the crimping component 50 by embossing. In addition, the concavoconvex portion may be formed on the back surface (and the surface) other than this, and the concavoconvex portion is not limited to the embossing.

[0051] The width L of the metal foil 36 cannot be extremely short due to the power (current value). On the other hand, the width L is required to be such that the floating height ΔT of the metal foil 36 is suppressed. The width L of the metal foil 36 can be determined according to the relationship between the allowable range of the floating height ΔT and the diameter D of the glass member 34.

[0052] Figure 5 The figure shows the relationship between the width L of the metal foil, the floating height ΔT, and the diameter D of the glass member 34. When it is considered that θ" ≒θ / 2, sin(θ / 2) ≒ΔT÷(L / 2), the floating height ΔT can be expressed by the following formula. Figure 5 Reference numeral 36 ′ indicates the position of the imaginary metal foil 36 .

[0053] ΔT=L / 2×sin(90L / πD)……(1)

[0054] It is empirically deduced that the floating height ΔT is 1.2 or less. Therefore, the width L of the metal foil 36 relative to the diameter D of the glass member 34 is determined to satisfy the following formula: The diameter D of the glass member 34 satisfies the range of 15≦D≦35 (mm).

[0055] L / 2×sin(90L / πD)≦1.2……(2)

[0056] Figure 6 2 is a cross-sectional view taken along the inner metal ring 26 before the crimping component 50 is welded to the metal foil 36. Figure 6 A method for manufacturing a discharge lamp is described. Figure 6 In FIG. 1 , the gap between the crimping component 50 and the metal foil 36 is exaggeratedly depicted.

[0057] A plurality of metal foils 36 are arranged in the axial direction along the surface of the columnar glass member 34, and the end portions 36T of the metal foils are welded to the outer peripheral surface 26S of the inner metal ring 26 into which the electrode support rod 22 is axially inserted. Then, a step of welding the crimping member 50 to the metal foil 36 along the outer peripheral surface 26S of the inner metal ring 26 is performed.

[0058] When the crimping component 50 is welded to the metal foil 36, spot welding is performed at least at one location for each metal foil 36 (see arrows). On the other hand, for the metal foil 36 facing the overlapping portion 50T of the crimping component 50, spot welding is performed at one to two locations or more at both ends. In this way, the metal foil 36 is welded and fastened by the crimping component 50. Although direct welding can be performed between the crimping component 50 and the inner metal ring 26, welding may not be performed for manufacturing efficiency.

[0059] When the welding of the crimping member 50 and the metal foil 36 is completed, the sealing step is entered. In the sealing step, the sealing tube 20 is heated by a gas burner or the like to reduce its diameter and is welded to the glass tube 24 and the glass member 34. Through such operations, the discharge lamp is manufactured.

[0060] Therefore, according to the present embodiment, in the discharge lamp 10 obtained by arranging a plurality of metal foils 36 along the lamp axis direction on the outer surface of a columnar glass component 34, and welding the metal foils 36 to the outer peripheral surface 26S of an inner metal ring 26 connected to an electrode support rod 22, an annular crimping component 50 presses the metal foil 36 on the outer peripheral surface 26S of the inner metal ring 26 and its vicinity toward the center side of the inner metal ring (glass component), thereby fastening the metal foil 36.

[0061] By providing the pressing member 50, the metal foil 36 can be prevented from floating from the outer surface of the glass member 34. As a result, it is possible to prevent the metal foil 36 from wrinkling or kinking at least at the end 36T during sealing. Figure 2 Therefore, the occurrence of floating is suppressed by the crimping component 50, so that the sealing of the blade-shaped portion along the surface of the glass component 34 can be performed.

[0062] In addition, the two edges 36K1 and 36K2 of the metal foil 36 are in contact with the concavo-convex portion formed in the crimping member 50. As a result, the two edges 36K1 and 36K2 of the metal foil 36 can be strongly pressed, and the floating of the metal foil 36 can be reliably suppressed. In addition, according to the above formula (2), the width L of the metal foil 36 does not become longer than the required length relative to the diameter of the glass member 34, and the floating height can be reduced.

[0063] In addition, the number of metal foils 36 is not limited to 6, and may be more than 6 or less than 6. In this case, the thickness and number of metal foils 36 may be adjusted in consideration of the heat capacity of the metal foil 36 and the welding area during sealing. In addition, the circumference of the pressing member 50 is set to be approximately one circle of the glass member 34 (inner metal ring 26), but the circumference may be set to two or three circles, and pressing may be performed by multiple circles.

[0064] Example

[0065] In order to show that the discharge lamp of this embodiment is effective, short arc discharge lamps (Example 1, Example 2) with different diameters of glass parts and widths of metal foil and conventional short arc discharge lamps (Comparative Example) were manufactured, and a comparative experiment on the generation of wrinkles and kinks in (the end of) the metal foil was conducted. Regarding the generation of wrinkles and kinks, a visual confirmation experiment was conducted. Table 1 shows the results of Comparative Example 1, Example 1, and Example 2.

[0066] Table 1

[0067] Glass component diameter D Metal foil width L Foil floating height H determination Comparative Example 20mm 10mm 1.237mm ╳ Example 1 20mm 8mm 0.795mm ○ Example 2 25mm 10mm 0.993mm ○

[0068] As shown in Table 1, in the comparative example, wrinkles and kinks were generated at the edge of the metal foil, but in Examples 1 and 2, wrinkles and kinks were not generated.

Claims

1. A discharge lamp, characterized in that The discharge lamp has: A columnar glass component is disposed in a sealing tube integrally formed with the light-emitting tube and is welded to the sealing tube; A plurality of metal foils extending between the sealing tube and the glass component along the lamp axis direction; a conductive annular member which contacts the plurality of metal foils at its outer peripheral surface and is connected to an electrode support rod arranged along the lamp axis; as well as an annular pressing member that presses the plurality of metal foils on the outer peripheral surface of the annular member so that the plurality of metal foils are along the surface of the glass member at least in the vicinity of the annular member, The width of the metal foil along the circumferential direction is determined to satisfy the following formula: L / 2×sin(90L / πD)≤1.2, Wherein, D represents the diameter of the glass component, and L represents the width of the metal foil, wherein the units of D and L are millimeters.

2. The discharge lamp according to claim 1, characterized in that The crimping member has a concave-convex portion that contacts the metal foil near at least two edges of the metal foil.

3. The discharge lamp according to claim 1 or 2, characterized in that The axial length of the region of the pressing member pressing the metal foil on the surface of the glass member is in the range of 0.5 to 2.0 times the axial length of the annular member.

4. The discharge lamp according to claim 1 or 2, characterized in that The crimping member has an overlapping portion at a position facing a predetermined metal foil.

5. The discharge lamp according to claim 1 or 2, characterized in that The crimping component is made of metal. The crimping component is welded to the metal foil.

6. A method for manufacturing a discharge lamp according to claim 1, characterized in that: A plurality of metal foils are arranged in a circumferential direction along a surface of a columnar glass member; welding the metal foil to the outer peripheral surface of the conductive annular member in contact with the electrode support rod; as well as The annular metal crimping member is welded to the plurality of metal foils on the outer peripheral surface of the annular member so that the plurality of metal foils are along the surface of the glass member at least in the vicinity of the annular member.

7. A method for manufacturing a discharge lamp according to claim 1, characterized in that: The mounting member of the discharge lamp includes a cylindrical glass tube, a columnar glass member, and a plurality of metal foils. In the manufacturing method, preparing a plurality of metal foils, wherein the floating height of the plurality of metal foils when in contact with the columnar glass member of the mounting member is 1.2 mm or less; welding the plurality of metal foils to the outer peripheral surface of the conductive annular member of the mounting member; and The annular metal crimping member is welded to the plurality of metal foils on the outer peripheral surface of the annular member.

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