Excimer lamp, method for lighting an excimer lamp, and method for manufacturing an excimer lamp

Abstract

To provide an excimer lamp capable of producing a desired discharge state in a main discharge space while improving the lighting start-up of the lamp.SOLUTION: An excimer lamp 10 includes an outer tube 20, a cladding tube 50' arranged coaxially in the outer tube 20 and covering a foil-shaped inner electrode 30, and an inner tube 60' covering the cladding tube 50'. An auxiliary discharge space S2 consisting of two relative discharge space areas S2A, S2B is formed between the cladding tube 50' and the inner tube 60'.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an excimer lamp, and more particularly to the configuration of a discharge space. [Background technology]

[0002] A double-tube structure lamp is known among excimer lamps (see Patent Document 1). In this lamp, a dielectric covering a foil-like inner electrode is placed inside a discharge tube, and a voltage is applied between an outer electrode and an inner electrode provided on the outer surface of the discharge tube. This causes excimer light such as ultraviolet rays to be emitted from the discharge space formed between the dielectric and the discharge tube.

[0003] Also, in order to reliably light a high-power excimer lamp, an excimer lamp is known that is equipped with a start-up assistance function that discharges at a voltage lower than the discharge start voltage (see Patent Document 2). In this lamp, a start-up assistance discharge space filled with a gas with a low starting voltage is formed along the lamp axis direction within the inner tube of the double-tube structure lamp. Ultraviolet light emitted from the start-up assistance discharge space irradiates the gas in the main discharge space, causing a discharge in the main discharge space. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2012-38658 A [Patent Document 2] JP 2017-4702 A Summary of the Invention [Problem to be solved by the invention]

[0005] When the discharge space for starting assistance is formed over the entire inner tube, ultraviolet light from the main discharge space is irradiated with uniform intensity to the outside of the lamp. However, in ultraviolet light irradiation devices and ozone generators equipped with excimer lamps, it is sometimes necessary to create a localized discharge state in the main discharge, thereby suppressing the ultraviolet light intensity (illuminance) and the ozone generation concentration.

[0006] Therefore, there is a need to provide an excimer lamp that is capable of producing a desired discharge state in the main discharge space while improving the lamp's lighting startability. [Means for solving the problem]

[0007] An excimer lamp according to one aspect of the present invention includes a first dielectric covering foil electrodes arranged along the lamp axis, a second dielectric covering the first dielectric, and a discharge vessel that is fused to the second dielectric to form a main discharge space. In the lamp axial range of the main discharge space, the first dielectric is partially fused to the second dielectric so that an auxiliary discharge space is formed between the first dielectric and the second dielectric.

[0008] The first dielectric can be welded to the second dielectric at least at both longitudinal ends of the first dielectric, and the auxiliary discharge space can be formed between an outer surface of the first dielectric and an inner surface of the second dielectric so that the electric field strength differs along at least one of the lamp axial direction and the lamp circumferential direction.

[0009] For example, the first dielectric and the second dielectric can be welded together in an area of ​​low electric field strength along at least one of the lamp axial direction and the lamp circumferential direction of the foil electrode, and an auxiliary discharge space can be formed in an area of ​​high electric field strength. In this case, the auxiliary discharge space may be formed between an outer surface portion of the first dielectric corresponding to a portion covering the edge of the foil electrode and the inner surface of the second dielectric.

[0010] Alternatively, the first dielectric may be fused to the second dielectric in an area of ​​high electric field strength along at least one of the lamp axial direction and the lamp circumferential direction of the foil electrode, and an auxiliary discharge space may be formed in an area of ​​low electric field strength. In this case, the auxiliary discharge space may be formed between the outer surface of the first dielectric and the inner surface of the second dielectric in accordance with the portion covering the side surface of the foil electrode.

[0011] It is possible to configure the tip of the first dielectric and / or the second dielectric so that the tip of the first dielectric and / or the second dielectric enters into a small diameter portion provided at the tip of the discharge vessel, and the tip of the foil electrode along the lamp axis is located rearward of the small diameter portion. Here, "entering the small diameter portion" means that the tip of the tip is located closer to the bottom of the small diameter portion than the end of the small diameter portion closer to the lamp center along the vessel axial direction.

[0012] The auxiliary discharge space can be formed such that the distance between the first dielectric and the second dielectric along the width direction of the foil electrode is shorter at the edge side than at the center, and the auxiliary discharge space can be formed such that the distance between the first dielectric and the second dielectric along the length direction of the foil electrode is shorter at the end side than at the center.

[0013] One aspect of the present invention is a method for operating an excimer lamp, in which an excimer lamp includes an inner tube consisting of a first dielectric covering an inner electrode arranged along the lamp axial direction and a second dielectric covering the first dielectric, and an outer tube welded to the expanded diameter portion of the inner tube to form a main discharge space, an auxiliary discharge space is formed between the outer surface of the first dielectric and the inner surface of the second dielectric within the lamp axial range of the main discharge space, and a portion of the light emitted from the auxiliary discharge space in the lamp axial direction is irradiated onto the main discharge space through the tip of the inner tube on the main discharge space side and the expanded diameter portion.

[0014] A method for manufacturing an excimer lamp according to one aspect of the present invention includes the steps of inserting an inner electrode into a glass tube that will become the covering tube, or covering the inner electrode with a dielectric that will become the covering tube, inserting the covering tube into the glass tube that will become the inner tube, reducing the pressure inside the inner tube and sealing it, or filling the inner tube with a rare gas at atmospheric pressure or lower, and heating and reducing the diameter of the inner tube to partially weld the inner tube to the covering tube so that an auxiliary discharge space is formed between the covering tube and the inner tube along the tube axis direction. For example, the outer tube is heat-welded integrally with the expanded diameter portion of the inner tube to form the main discharge space. Effect of the Invention

[0015] According to the present invention, it is possible to provide an excimer lamp that is capable of generating a desired discharge state in the main discharge space while improving the lamp lighting startability. [Brief description of the drawings]

[0016] [Figure 1] 1 is a schematic cross-sectional view of an excimer lamp according to a first embodiment, viewed from the side. [Diagram 2] 1 is a schematic cross-sectional view of an excimer lamp according to a first embodiment, viewed from the axial direction. [Diagram 3] 10 is a schematic cross-sectional view of a foil electrode of an excimer lamp according to a second embodiment, viewed from the side along the width direction. FIG. [Figure 4] 10 is a schematic cross-sectional view of a foil electrode of an excimer lamp according to a second embodiment, viewed from the side along the thickness direction. FIG. [Diagram 5] 1 is a schematic cross-sectional view of an excimer lamp according to a second embodiment, seen from the side. [Figure 6] 11 is a schematic cross-sectional view of a foil electrode of an excimer lamp according to a third embodiment, viewed from the side along the width direction. FIG. [Figure 7] 11 is a schematic cross-sectional view of a foil electrode of an excimer lamp according to a third embodiment, viewed from the side along the thickness direction. FIG. [Figure 8] 11 is a schematic cross-sectional view of an excimer lamp according to a third embodiment, as viewed from the axial direction. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0018] Fig. 1 is a schematic cross-sectional view of the excimer lamp according to the first embodiment as viewed from the side. Fig. 2 is a schematic cross-sectional view of the excimer lamp according to the first embodiment as viewed from the axial direction. Fig. 2 corresponds to a cross-sectional view taken along line BB in Fig. 1. The cross-sectional view in Fig. 1 corresponds to a cross-sectional view taken along a line passing through the central axis of the lamp in Fig. 2.

[0019] The excimer lamp 10 comprises a coaxially arranged outer tube 20 having a substantially cylindrical cross section and made of a dielectric material such as quartz glass, and a columnar (film-like) first dielectric (hereinafter referred to as the covering tube) 50 which covers a foil electrode (hereinafter referred to as the inner electrode) 30 which extends in a band shape having a width along the radial direction (hereinafter referred to as the lamp radial direction) C, and a cylindrical second dielectric (hereinafter referred to as the inner tube) 60 which covers the covering tube 50, is welded to the covering tube 50 along part of the axial direction and extends along the lamp axis C.

[0020] The covering tube 50 and the inner tube 60 are arranged coaxially with the outer tube 20, and the inner electrode 30 is arranged coaxially with the outer tube 20 so that its center position in the width direction and thickness direction is aligned with the lamp axis C. The inner electrode 30 is arranged symmetrically with respect to the tube axis C. One end 20T2 of the outer tube 20 is heat-welded integrally with the expanded diameter portion 61 of the inner tube 60, thereby forming a discharge space (main discharge space) S1.

[0021] A rare gas such as xenon gas or a mixed gas of a rare gas and a halogen gas is filled as a discharge gas in the main discharge space S1. The pressure of the discharge gas is set to, for example, 5 kPa to 150 kPa.

[0022] The discharge vessel 10T has protruding portions (hereinafter referred to as small diameter portions) 22, 62 on both ends of a constant inner diameter portion (hereinafter referred to as a cylindrical portion) 20T0 that surrounds the main discharge space S1. The small diameter portion 62 is a portion of the rear end side of the inner tube 60 that is not covered by the outer tube 20 and protrudes along the lamp axis C toward the rear end of the lamp, and is penetrated inside by a power supply line 70 and the small diameter portion 52 of the covering tube 50 that covers it. It is also possible to cover the power supply line 70 with the small diameter portion 62 of the inner tube 60 so that the covering tube 50 is not exposed on the end side.

[0023] The small diameter portion 22 is formed during the lamp manufacturing process, and protrudes from the discharge vessel 10T (outer tube 20) along the lamp axis C towards the lamp tip side. Here, the tip side of the outer tube 20 is heated and deformed to reduce its diameter, and a tip tube with a smaller diameter than the outer tube 20 is welded to form the small diameter portion 22, which is a partial section of the lamp axial direction range of the discharge vessel 10T and has a smaller diameter than the range (axial arrangement range) L along the lamp axial direction in which the outer electrode 40 is arranged, as an integral part. Note that the tip tube used in the lamp manufacturing may be provided at a position separate from the small diameter portion.

[0024] The end 50T1 of the cladding tube 50 enters the small diameter portion 22 and comes into contact with the small diameter portion 22, so that the cladding tube 50 is stably held coaxially within the outer tube 20. Furthermore, the end 50T1 of the cladding tube 50 has an outer surface that is tapered into a convex curve, while the inner surface of the small diameter portion 22 forms a tapered into a concave curve. This allows the cladding tube 50 to be stably held coaxially with the discharge vessel 10T so that it will not be damaged even if there are dimensional errors due to the respective heat forming processes.

[0025] It is also possible to configure the tip end 60T1 of the bottomed cylindrical inner tube 60, which covers the tip end 50T1 of the covering tube 50, to fit into the small diameter portion 22. While forming such a fitted state, the position of the tip end 30T1 of the inner electrode 30 along the lamp axis C may be located closer to the rear end (the center of the discharge vessel) than the small diameter portion 22, without fitting into the internal space of the small diameter portion 22.

[0026] An electrode (hereinafter referred to as the outer electrode) 40 is disposed on the outer surface 20S of the outer tube 20. The outer electrode 40 is configured by winding a linear electrode portion made of a conductive metal along the surface of the outer tube 20, and is wound in a spiral shape along the tube axis C at predetermined intervals.

[0027] The axial arrangement range L of the outer electrode 40 is determined in a cylindrical portion 20T0 that is a constant inner diameter portion between the tapered ends 20T1, 20T2 of the outer tube 20. The axial length of the inner electrode 30 corresponds to the axial arrangement range L of the outer electrode 40. A power supply line 70 connected to an end of the inner electrode 30 is connected to an externally installed power supply unit (not shown), and power is supplied to the excimer lamp 10 via the power supply line 70.

[0028] Excimer light is emitted from the discharge space S1 by applying a high frequency (for example, in the range of several kHz to several tens of MHz) and a high voltage (for example, in the range of several kV to several tens of kV) to the inner electrode and the outer electrode. Here, ultraviolet light (for example, a wavelength of 172 nm) is emitted to the outside of the discharge vessel. Therefore, the excimer lamp 10 can be used in an ozone generator that generates ozone to sterilize, deodorize, etc., and can also be used in an ultraviolet irradiation device that directly irradiates an object with ultraviolet light.

[0029] A discharge space S2 for assisting in starting the lamp (hereinafter referred to as auxiliary discharge space) is formed between the covering tube 50 and the inner tube 60. As shown in Figs. 1 and 2, the inner electrode 30 is sealed (closely attached) to the inner tube 60 over the entire direction of the lamp axis C and over the entire circumference of the inner electrode 30. The covering tube 50 has a substantially elliptical cross-sectional shape, whereas the inner tube 60 has a substantially circular cross-sectional shape. An annular main discharge space S1 is formed between the inner tube 60 and the outer tube 20, and an auxiliary discharge space S2 is formed between the outer surface of the inner tube 60 and the inner surface of the inner tube 60.

[0030] Here, the auxiliary discharge space range (auxiliary discharge range) M of the auxiliary discharge space S2 along the lamp axial direction is slightly shorter than the axial arrangement range L of the outer electrode 40. Therefore, near both ends 30T1, 30T2 of the inner electrode 30, the outer peripheral surface of the covering tube 50 and the inner peripheral surface of the inner tube 60 are sealed over the entire circumferential direction. In contrast, in the intermediate portion including the center in the lamp axial direction of the inner electrode 30, the entire outer peripheral surface of the inner tube 60 is exposed, and the auxiliary discharge space S2 is formed to surround it. Also, compared to other ranges, in the auxiliary discharge space range M, the outer diameter of the inner tube 60 is larger and the distance between the outer surface of the inner tube 60 and the inner surface of the outer tube 20 is smaller.

[0031] At both ends ST1, ST2 of the inner surface of the inner tube 60 exposed to the auxiliary discharge space S2 (both ends of the auxiliary discharge space range M), the distance between the cladding tube 50 and the inner tube 60 gradually decreases, and the discharge space region narrows toward both ends 50T1, 50T2 of the inner tube 60. Then, the inner tube 60 is welded to the cladding tube 50 while the distance between the inner surface of the inner tube 60 and the outer surface of the cladding tube 50 gradually decreases. The outer diameter of the inner tube 60 also gradually decreases, and the outer surface forms a smoothly curved surface.

[0032] 1, the spatial shape of the auxiliary discharge space S2 has a wider radial cross-sectional area toward the center of the lamp (auxiliary discharge space range M) and the spatial area narrows toward the small diameter parts 22, 52 at both ends of the discharge vessel 10T. Therefore, the distance L1 along the lamp radial direction between the outer circumferential surface of the inner tube 60 and the inner circumferential surface of the inner tube 60 in the central part along the lamp axis C of the auxiliary discharge space S2 is longer than the distance L2 at both ends ST1, ST2 of the inner surface of the inner tube 60 exposed to the auxiliary discharge space S2.

[0033] In addition, both edge portions 30T3, 30T4 of the foil-like inner electrode 30 have a knife-edge shape, and the inner electrode 30 becomes sharp from the center in the width direction toward the edge (end portion), and the thickness of the inner electrode 30 becomes thinner than the thickness of the center portion in the width direction, and both edge portions 30T3, 30T4 are sharp. The radial cross section of the inner tube covering this foil-like inner electrode 30 is short (minor axis direction) in the thickness direction of the foil-like inner electrode 30, and the major axis direction is determined along the width direction.

[0034] 3, the auxiliary discharge space S2 has a wider radial cross-sectional area toward the center in the width direction (lamp radial direction) of the inner electrode 30. Therefore, the length of the separation distance between the inner surface of the inner tube 60 and the outer surface of the inner tube 60 along the lamp radial direction is such that the length T1 of the separation distance along the thickness direction near the center (lamp central axis) is longer than the length T2 (corresponding to L1 in FIG. 1) of the separation distance along the width direction near both edges 30T3, 30T4 of the inner electrode 30, and the length narrows toward both edges 30T3, 30T4 of the inner electrode 30.

[0035] The auxiliary discharge space S2 tapers so that the discharge space area gradually becomes smaller at both ends 30T1, 30T2 in the length direction (lamp axial direction) and edges 30T3, 30T4 in the width direction (lamp radial direction) along the surface of the foil-shaped inner electrode 30.

[0036] In this way, by configuring an excimer lamp 10 with a triple-structure discharge vessel 10T that forms a main discharge space S1 and an auxiliary discharge space S2 while arranging the covering tube 50 and the inner tube 60 coaxially with the outer tube 20, it is possible to form the auxiliary discharge space S2 without significantly changing the outer shape of a conventional excimer lamp with a double-tube structure. In addition, by using a film-like covering tube, it is possible to make the outer shape equivalent to that of a conventional excimer lamp with a double-tube structure.

[0037] As described above, electric field concentration occurs near the edges 30T3 and 30T4 of the inner electrode 30 because the edges 30T3 and 30T4 have a knife-edge shape. Meanwhile, because the covering tube 50 has an elliptical cross section, the electric field strength varies in the circumferential direction in the auxiliary discharge space S2 during discharge, and spatial regions with high electric field strength are formed near the edges 30T3 and 30T4 of the inner electrode 30.

[0038] However, since each of them is embedded in the covering tube 50 and is not exposed to the auxiliary discharge space S2, wear of the inner electrode 30 due to discharge can be suppressed. Also, the position of the inner electrode 30 relative to the inner tube 60, i.e., the radial cross-sectional length direction, can be adjusted in the manufacturing process. Note that the cross-sectional shape of the covering tube 50 can also be circular, and the cross-sectional shape of the inner tube 60 can also be elliptical.

[0039] The auxiliary discharge space S2 is either in a reduced pressure state lower than atmospheric pressure, or is filled with a rare gas (lower than atmospheric pressure) that lowers the voltage at the start of lighting. When a high-frequency high voltage is applied between the inner electrode 30 and the outer electrode 40, a discharge occurs first in the auxiliary discharge space S2 due to the reduced pressure state of the auxiliary discharge space S2, and the start-of-light voltage is lower than that in the main discharge space S1. Then, part of the light (ultraviolet light in this case) emitted from the auxiliary discharge space S2 in the lamp radial direction is irradiated to the main discharge space S1 through the inner tube 60.

[0040] In addition, a portion of the light emitted from the auxiliary discharge space S2 in the lamp axial direction is transmitted toward the ends 50T1, 50T2, 60T1, and 60T2 due to a fiber effect (an effect based on the same principle as optical fibers used in communication circuits) caused by repeated reflection within the tube walls (boundary surfaces of the tube walls) of the covering tube 50 and the inner tube 60.

[0041] Here, a part of the end 50T1 of the covering tube 50 (end 60T1 of the inner tube 60) enters into and contacts the small diameter portion 22, and an expanded diameter portion 61 is provided on the end 60T2 side of the inner tube 60 (end 50T2 of the covering tube 50). Therefore, ultraviolet light guided by the fiber effect passes through the end 60T1 of the inner tube 60 (end 50T1 of the covering tube 50) and the expanded diameter portion 61 and is irradiated into the main discharge space S1 from both ends 20T1, 20T2 of the outer tube 20. As a result, a discharge occurs in the main discharge space S1.

[0042] The auxiliary discharge space S2 thus partially formed within the inner tube 60 improves the lighting startability. On the other hand, the auxiliary discharge space S2 only needs to be formed as a minute spatial region that generates a minute discharge that allows the emitted light to reach the main discharge space, and therefore does not secure a space that occupies most of the interior of the inner tube 60, and is formed as a partial discharge space region. Therefore, the voltage applied between the inner electrode 30 and the outer electrode 40 during lamp lighting is suppressed, and the required power is reduced, thereby improving the lamp durability and lamp life.

[0043] Furthermore, the illuminance distribution (light distribution) along the outer peripheral surface of the discharge vessel varies depending on the shape of the discharge vessel and the position of the discharge generated inside it. Furthermore, the discharge state is affected by the electric field strength distribution determined by the positional relationship of the electrodes (anode and cathode) and the shapes of the covering tube, inner tube, and auxiliary discharge space. However, since the above-mentioned excimer lamp 10 does not change the outer shape or discharge state of a conventional excimer lamp with a double-tube structure, it is possible to improve the lighting startability in an ultraviolet irradiation device or an ozone generator without affecting lamp characteristics such as discharge sustaining voltage and illuminance distribution or power supply characteristics suitable for them.

[0044] The lighting startability can be understood by the certainty (probability [%]) that a stable lighting state where a desired radiation spectrum is obtained from the discharge in the discharge vessel when a voltage is applied to the excimer lamp is reached. An excimer lamp is required to have certainty of lighting startability (100% reliability) even in low temperature conditions, in darkness, or after a long period of inactivity, but in this embodiment, a stable lighting state can be reliably reached without using a large lighting power supply or a light source for auxiliary lighting start, that is, lighting startability can be practically 100% certain.

[0045] According to the above configuration, it is possible to radiate ultraviolet rays toward the entire discharge space S1, and a stable main discharge can be realized in the discharge space S1. Meanwhile, the auxiliary discharge space S2 is defined as a partial section of the axial arrangement range of the inner electrode 30 so that the electric field strength is approximately uniform along the lamp axis C. Therefore, the ultraviolet light irradiated from the discharge vessel 10T to the outside of the lamp can have a uniform illuminance distribution along the lamp axis C.

[0046] Furthermore, the spatial region of the auxiliary discharge space S2 changes asymptotically, i.e., the change in the inner shape of the inner tube 60 becomes smooth, improving the stability of the lamp intensity and other properties caused by stress concentration on curved portions (for example, both ends ST1, ST2 of the inner surface of the inner tube 60 exposed to the auxiliary discharge space S2). Therefore, even when the inner tube 60 deteriorates (becomes embrittled) due to high-energy ultraviolet rays generated by the main discharge in the discharge space S1, damage to the discharge vessel 10T originating from the portion covering the auxiliary discharge space S2 can be prevented.

[0047] The excimer lamp 10 of the first embodiment can be manufactured, for example, as follows.

[0048] First, a glass tube (inner tube) with a cylindrical cross section is formed to serve as a covering for the foil-like inner electrode. After the inner tube is formed, a power supply wire is connected to the inner electrode by resistance welding or the like, and the inner electrode is inserted into the cylindrical inner tube with a bottom. After the inner electrode is inserted, the inside of the tube is reduced in pressure (vacuum) and sealed.

[0049] The inner tube is heated while being rotated, and the glass tube is softened and deformed so as to shrink (reduced in diameter). At this time, the inner electrode is brought into close contact with the glass tube over the entire circumferential direction and the entire axial direction. The diameter is reduced so as to have an elliptical cross section. Note that a dielectric may be coated on at least the surface of the inner electrode in the auxiliary discharge space range M as a covering tube.

[0050] Then, a covering tube that covers the inner electrode is formed from a dielectric material that is transparent to the light emitted from the discharge formed in the auxiliary discharge space, and then a glass tube (inner tube) that covers the covering tube is formed. After forming the covering tube and the inner tube, the covering tube is inserted into the inner tube and heated to reduce its diameter.

[0051] At this time, the inner tube is heated to partially weld along the lamp axis so as to form an auxiliary discharge space. In addition to forming the auxiliary discharge space, a brim-shaped (so-called abacus bead-shaped) sealing portion is formed at one end of the inner tube. Note that the inner tube may not be rotated, and only the inner circumferential surface and the edge of the foil electrode may be heated to tightly adhere to each other.

[0052] For the outer tube, one end of a quartz tube that is transparent to the wavelengths of ultraviolet light emitted from the discharge formed in the main discharge space is reduced in diameter and an open introduction tube (tip tube) is provided, while the outer tube is formed with an open sealing portion with the inner tube. The inner tube is then inserted into the outer tube and arranged coaxially, and the sealing portion is heat-fused to form a discharge tube. After that, a vacuum is drawn through the introduction tube to remove impurities, and a discharge gas is sealed inside the arc tube and the introduction tube is heat-fused to hermetically seal it. An outer electrode is then disposed on the outer surface of the outer tube.

[0053] Next, an excimer lamp according to a second embodiment will be described with reference to Figures 3 to 5. In the second embodiment, the covering tube and the inner tube are partially welded together so as to cover the side surface of the foil electrode along the circumferential direction, thereby forming an auxiliary discharge space in an area facing the edge of the foil electrode, and the auxiliary discharge space is formed between the covering tube and the inner tube along the lamp axial direction.

[0054] Fig. 3 is a schematic cross-sectional view of a foil electrode of an excimer lamp according to a second embodiment, viewed from the side along the width direction. Fig. 4 is a schematic cross-sectional view of a foil electrode of an excimer lamp according to a second embodiment, viewed from the side along the width direction. Fig. 5 corresponds to a cross-sectional view taken along line BB in Fig. 4. The cross-sectional view in Fig. 5 corresponds to a cross-sectional view taken along a line passing through the central axis of the lamp in Fig. 4.

[0055] 5, the covering tube 50' has a circular cross section in the lamp radial direction after being sealed to the foil-shaped inner electrode 30. On the other hand, the inner tube 60' has an elliptical cross section in the lamp radial direction after being welded to the covering tube 50'. In the lamp radial cross section, an inner surface portion 60'K2 along the minor axis direction (thickness direction of the inner electrode 30) of the inner tube 60' is welded to an outer surface portion of the covering tube 50' covering the side surfaces 30S1 and 30S2 of the inner electrode 30.

[0056] As a result, an auxiliary discharge space S2 consisting of discharge space regions S2A, S2B separated into two spaces is formed between an inner surface portion 60'K1 along the longitudinal direction of the inner tube 60' (width direction of the inner electrode 30) and an outer surface portion of the covering tube 50' covering the edges 30T3, 30T4 of the inner electrode 30.

[0057] In the inner tube 60', the two discharge space regions S2A and S2B are spatially separated by the cladding tube 50'. Also, in the second embodiment, unlike the first embodiment, the cross-sectional shape of the inner tube 60' is elliptical, while the cross-sectional shape of the cladding tube 50' is circular.

[0058] The discharge space regions S2A, S2B are positioned opposite each other in the width direction of the inner electrode 30, and are symmetrical with respect to the radial cross section. The axial section (auxiliary discharge section) M of the auxiliary discharge space S2 has a length along the lamp axis C that is slightly shorter than the axial arrangement section L of the outer electrode 40. Therefore, near both ends 30T1, 30T2 of the inner electrode 30, the outer peripheral surface of the covering tube 50' and the inner peripheral surface of the inner tube 60' are sealed over the entire circumferential direction. In addition, in the auxiliary discharge space region M, the outer diameter of the inner tube 60' is larger than in other regions, and the distance between the outer surface of the inner tube 60' and the inner surface of the outer tube 20 is smaller.

[0059] In contrast, in an intermediate portion between both ends 30T1, 30T2 of the inner electrode 30, including the center of the inner electrode 30 in the lamp axial direction, the covering tube 50' and the inner tube 60' are welded to each other in a portion along the circumferential direction only in portions covering both side surfaces 30S1, 30S2 of the inner electrode 30. As a result, an auxiliary discharge space S2 (S2A, S2B) is formed in the space portion in the direction in which both edge portions 30T3, 30T4 of the inner electrode 30 face.

[0060] In the discharge space regions SAT1, SAT2, SBT1, and SBT2 at both ends of the auxiliary discharge space S2, the distance between the cladding tube 50' and the inner tube 60' gradually decreases, and the discharge space region narrows toward both ends 50T1 and 50T2 of the cladding tube 50', as in the first embodiment. The distance between the inner surface of the inner tube 60' and the outer surface of the cladding tube 50' gradually decreases, and the inner tube 60' is sealed to the cladding tube 50'. The outer diameter of the inner tube 60' also gradually decreases, and the outer surface forms a smoothly curved surface.

[0061] 4, the spatial shape of the auxiliary discharge space S2 has a wider radial cross-sectional area toward the center of the lamp (auxiliary discharge space range M) and the spatial area becomes narrower toward the discharge space areas SAT1, SAT2, SBT1, and SBT2 at both ends of the auxiliary discharge space S2. Therefore, the distance L1 along the lamp radial direction between the outer circumferential surface of the covering tube 50' and the inner circumferential surface of the inner tube 60' in the central part of the auxiliary discharge space S2 along the lamp axis C is longer than the distance L2 in the discharge space areas SAT1 (SBT1) and SAT2 (SBT2) at both ends of the auxiliary discharge space S2.

[0062] Therefore, in the lamp radial cross-sectional shape of the discharge space regions S2A, S2B, the length of the distance between the inner surface of the inner tube 60' and the outer surface of the covering tube 50' along the lamp radial direction is shorter than the length T2 of the distance along the width direction of the inner electrode 30 (edges 30T3, 30T4) of the inner electrode 30, i.e., the length T1 of the distance on the thickness direction (side surfaces 30S1, 30S2) of the inner electrode 30, and tapers along the lamp circumferential direction.

[0063] Because the auxiliary discharge space S2 (discharge space regions S2A, S2B) is configured so that the discharge space region gradually becomes smaller and tapers in both the lamp radial and circumferential directions, when a high-frequency high voltage is applied between the inner electrode 30 and the outer electrode 40, a spatial region with high electric field strength is formed in the reduced-pressure auxiliary discharge space S2 on the width direction (near both edges 30T3, 30T4) of the inner electrode 30. As a result, discharge occurs first in the auxiliary discharge space S2 at a lighting start voltage lower than in the main discharge space S1, and discharge occurs in the spatial region with high electric field strength in the main discharge space S1, making it easier to transition to stable (rated) lighting.

[0064] Moreover, the electric field strength in the main discharge space S1 differs in the lamp circumferential direction and is approximately equal in the lamp axial direction. As a result, localized discharge is likely to occur in the main discharge space S1 as well, and ultraviolet rays are emitted so that the ultraviolet ray intensity (illuminance distribution) is biased along the lamp circumferential direction and is uniform along the lamp axial direction C. This enables ultraviolet ray irradiation and ozone generation that are suited to the usage environment of the ultraviolet ray irradiation device and ozone generator.

[0065] The auxiliary discharge space S2 is formed by welding the cladding tube 50 to the inner tube 60 in part of the circumferential direction, and this makes the change in the spatial area of ​​the auxiliary discharge space S2 asymptotic, i.e., the change in the inner shape of the cladding tube 50 smooth, improving the stability of the lamp strength and other properties caused by stress concentration on the curved surface. Therefore, even if the cladding tube 50' or the inner tube 60' deteriorates (becomes embrittled) due to high-energy ultraviolet rays generated by the main discharge in the discharge space S1, damage to the discharge vessel 10T originating from the part covering the auxiliary discharge space S2 can be prevented.

[0066] The excimer lamp of the second embodiment can be manufactured as follows. First, as in the first embodiment, an inner electrode is inserted into a glass tube that will be a covering tube, and the glass tube is heated to reduce its diameter. At this time, the inner electrode is brought into close contact with the glass tube over the entire circumferential direction and the entire axial direction. The diameter is reduced so that the cross section is circular. The surface of the inner electrode may be coated with a dielectric. Then, the covering tube covered with the inner electrode is inserted into an inner tube that is a glass tube, and heated to reduce its diameter. At this time, heating and reduction are performed to weld a part of the circumferential direction of the inner tube to the covering tube along the lamp axis C direction so as to form two discharge space regions S1 and S2. The other configurations are the same as those in the process of the first embodiment.

[0067] Next, an excimer lamp according to a third embodiment will be described with reference to Figures 6 to 8. In the third embodiment, the covering tube and the inner tube are partially welded together so as to cover the edge of the foil electrode along the circumferential direction, thereby forming an auxiliary discharge space in an area facing the side surface of the foil electrode, and the auxiliary discharge space is formed between the covering tube and the inner tube along the lamp axial direction.

[0068] Fig. 6 is a schematic cross-sectional view of the foil electrode of the excimer lamp of the third embodiment as viewed from the side in the width direction. Fig. 7 is a schematic cross-sectional view of the foil electrode of the excimer lamp of the third embodiment as viewed from the side in the thickness direction. Fig. 8 is a schematic cross-sectional view of the excimer lamp of the third embodiment as viewed from the axial direction.

[0069] As shown in FIG. 8, in an excimer lamp 10 according to the third embodiment, a covering tube 50" has an elliptical cross section in the lamp radial direction. On the other hand, an inner tube 60" has a circular cross section in the lamp radial direction. In the lamp radial cross section, the inner surface portion of the inner tube 60" covering the edge portions 30T3, 30T4 of the inner electrode 30 is welded to an outer surface portion 50"K1 along the major axis direction of the covering tube 50" (width direction of the inner electrode 30).

[0070] Two spatially separated spatial regions are formed between the inner surface portion of the inner tube 60" covering the side surface of the inner electrode 30 and the outer surface portion 50"K1 along the short axis direction (thickness direction of the inner electrode) of the covering tube 50", and these two spatial regions are auxiliary discharge spaces S2A and S2B, forming the auxiliary discharge space S2.

[0071] As in the second embodiment, the two discharge space regions S2A and S2B are spatially separated by the covering tube 50'', but in the third embodiment, the cross-sectional shape of the inner tube 60'' is circular, while the cross-sectional shape of the covering tube 50'' is elliptical. The discharge space regions S2A and S2B are positioned opposite each other in the thickness direction of the inner electrode 30 and are symmetrical with respect to the radial cross section.

[0072] In the lamp radial cross-sectional shape of the discharge space regions S2A, S2B, the length of the distance along the lamp radial direction between the inner surface of the inner tube 60" and the outer surface of the covering tube 50" is longer in the thickness direction (side surfaces 30S1, 30S2) of the inner electrode 30 than in the width direction (edges 30T3, 30T4) of the inner electrode 30, and the discharge space regions S2A, S2B taper along the lamp circumferential direction.

[0073] With this configuration, when a high-frequency high voltage is applied between the inner electrode 30 and the outer electrode 40, a discharge occurs first in the auxiliary discharge space S2, which is in a reduced pressure state, at a lower lighting start voltage than in the main discharge space S1, and accordingly, a discharge occurs in a spatial region in the main discharge space S1 where the electric field strength is high, making it possible to transition to stable (rated) lighting.

[0074] As described above, according to the third embodiment, the two discharge space regions S2A, S2B in the inner tube 60″ can be formed at desired positions by adjusting the shapes of the covering tube and the inner tube and the welded portions along the circumferential direction, regardless of the cross-sectional length direction (extension direction) of the foil-shaped inner electrode 30.

[0075] The above-described excimer lamp 10 can be manufactured by the same manufacturing process as in the second embodiment.

[0076] The axial section M of the auxiliary discharge space S2 is configured to correspond to the axial arrangement section L of the outer electrode 40, but the auxiliary discharge space S2 may be formed partially between the inner tube 60 and the covering tube 50 along the lamp axis C, for example, at the center or end of the lamp.

[0077] The outer electrodes may be embedded in the inner wall of the discharge tube so as to face each other, or one may be embedded and the other disposed on the outer surface of the discharge tube. The light emitted from the auxiliary discharge space is not limited to ultraviolet light, but may be visible light. [Explanation of symbols]

[0078] 10 Excimer Lamp 20 Outer tube 30 inner electrode 40 outer electrode 50 Cladding tube (dielectric) 60 Inner tube (dielectric)

Claims

1. a first dielectric covering a foil electrode disposed along the lamp axial direction; A second dielectric covering the first dielectric; a discharge vessel that is fused to the second dielectric to form a main discharge space, An excimer lamp characterized in that, in the lamp axial range of the main discharge space, the first dielectric is partially welded to the second dielectric so that an auxiliary discharge space is formed between the first dielectric and the second dielectric, the entire space being surrounded by the main discharge space.

2. The first dielectric is fused to the second dielectric at at least one end of the first dielectric in the longitudinal direction, 2. The excimer lamp of claim 1, wherein the auxiliary discharge space is formed between the outer surface of the first dielectric and the inner surface of the second dielectric so that the electric field strength varies along at least one of the lamp axial direction and the lamp circumferential direction.

3. A first dielectric covering a foil electrode arranged along the lamp axial direction; A second dielectric covering the first dielectric; a discharge vessel that is fused to the second dielectric to form a main discharge space, the first dielectric is partially fused to the second dielectric in a range of the main discharge space in the lamp axial direction so that an auxiliary discharge space is formed between the first dielectric and the second dielectric; The first dielectric is fused to the second dielectric at at least one end of the first dielectric in the longitudinal direction, the auxiliary discharge space is formed between an outer surface of the first dielectric and an inner surface of the second dielectric such that an electric field intensity varies along at least one of a lamp axial direction and a lamp circumferential direction, An excimer lamp characterized in that the foil electrode has the first dielectric and the second dielectric fused together in an area of ​​low electric field strength along at least one of the lamp axial direction and the lamp circumferential direction of the foil electrode, and the auxiliary discharge space is formed in an area of ​​high electric field strength.

4. A first dielectric covering a foil electrode arranged along the lamp axial direction; A second dielectric covering the first dielectric; a discharge vessel that is fused to the second dielectric to form a main discharge space, the first dielectric is partially fused to the second dielectric in a range of the main discharge space in the lamp axial direction so that an auxiliary discharge space is formed between the first dielectric and the second dielectric; The first dielectric is fused to the second dielectric at at least one end of the first dielectric in the longitudinal direction, the auxiliary discharge space is formed between an outer surface of the first dielectric and an inner surface of the second dielectric such that an electric field intensity varies along at least one of a lamp axial direction and a lamp circumferential direction, An excimer lamp characterized in that the first dielectric is fused to the second dielectric in areas of high electric field strength along at least one of the lamp axial direction and the lamp circumferential direction of the foil electrode, and the auxiliary discharge space is formed in areas of low electric field strength.

5. 4. The excimer lamp according to claim 3, wherein the auxiliary discharge space is formed between an outer surface portion of the first dielectric corresponding to a portion covering the edge of the foil electrode and an inner surface of the second dielectric.

6. An excimer lamp as described in any one of claims 2 to 5, characterized in that the auxiliary discharge space is formed between the outer surface of the first dielectric and the inner surface of the second dielectric, corresponding to the portion covering the side of the foil electrode.

7. a tip position of the tip portion of the first dielectric and / or the second dielectric enters into a small diameter portion provided at the tip of the discharge vessel, 7. The excimer lamp according to claim 1, wherein a tip position of the foil electrode along the lamp axis is located rearward of the small diameter portion.

8. A first dielectric covering a foil electrode arranged along the lamp axial direction; A second dielectric covering the first dielectric; a discharge vessel that is fused to the second dielectric to form a main discharge space, the first dielectric is partially fused to the second dielectric in a range of the main discharge space in the lamp axial direction so that an auxiliary discharge space is formed between the first dielectric and the second dielectric; An excimer lamp characterized in that the auxiliary discharge space is formed so that the distance between the first dielectric and the second dielectric along the width direction of the foil electrode is shorter at the edge side than at the center.

9. A first dielectric covering a foil electrode arranged along the lamp axial direction; A second dielectric covering the first dielectric; a discharge vessel that is fused to the second dielectric to form a main discharge space, the first dielectric is partially fused to the second dielectric in a range of the main discharge space in the lamp axial direction so that an auxiliary discharge space is formed between the first dielectric and the second dielectric; An excimer lamp characterized in that the auxiliary discharge space is formed so that the distance between the first dielectric and the second dielectric along the longitudinal direction of the foil electrode is shorter at the ends than at the center.

10. An excimer lamp includes an inner tube including a first dielectric covering an inner electrode disposed along a lamp axis direction and a second dielectric covering the first dielectric, and an outer tube fused to an enlarged diameter portion of the inner tube to form a main discharge space, an auxiliary discharge space is formed between an outer surface of the first dielectric and an inner surface of the second dielectric in a range of the main discharge space in the lamp axial direction, the entire space being surrounded by the main discharge space; A method for operating an excimer lamp, comprising the steps of: irradiating a portion of the light emitted from the auxiliary discharge space in the lamp axial direction to the main discharge space through the tip of the inner tube on the main discharge space side and the expanded diameter portion.

11. a step of inserting an inner electrode into a glass tube that will become a covering tube, or covering the inner electrode with a dielectric that will become a covering tube; a step of inserting the covering tube into a glass tube that becomes an inner tube so as to form a main discharge space; a step of reducing the pressure inside the inner tube and sealing it, or sealing a rare gas in the inner tube at atmospheric pressure or lower; a step of heating and reducing the diameter of the inner tube to partially fuse the inner tube to the covering tube so that an auxiliary discharge space is formed between the covering tube and the inner tube, the entire space being surrounded by the main discharge space along the tube axis direction; A method for manufacturing an excimer lamp, comprising:

12. 12. The method for manufacturing an excimer lamp according to claim 11, wherein the main discharge space is formed by heat-welding a discharge vessel integrally with the expanded diameter portion of the inner tube.

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