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

Abstract

The present invention provides an excimer lamp, a method for lighting an excimer lamp, and a method for manufacturing an excimer lamp. The excimer lamp can improve the lighting and starting performance of the lamp and perform lighting based on effective main discharge. The excimer lamp (10) comprises an outer tube (20) and an inner tube (50) coaxially arranged inside the outer tube (20), wherein the inner tube (50) covers an inner electrode (30). A main discharge space (S1) is formed between the outer tube (20) and the inner tube (50). In addition, a discharge space (auxiliary discharge space) (S2) for assisting lighting and starting is formed between the inner electrode (30) and the inner tube (50).

Description

Technical Field

[0001] The present invention relates to an excimer lamp, and in particular to the structure of a discharge space. Background Art

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

[0003] Furthermore, an excimer lamp with a starting assist function is known, which discharges at a voltage lower than the discharge start voltage to reliably ignite a high-output excimer lamp (see Patent Document 2). Within the inner tube of a double-tube lamp, a starting assist discharge space is formed along the lamp axis, enclosing a gas with a low starting voltage. Ultraviolet light emitted from the starting assist discharge space irradiates the gas in the main discharge space, thereby generating a discharge in the main discharge space.

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2012-38658

[0005] Patent Document 2: Japanese Patent Application Laid-Open No. 2017-4702 Summary of the Invention

[0006] There is a demand for an excimer lamp that can improve the lighting starting performance of the lamp and perform lamp lighting by efficient main discharge.

[0007] The excimer lamp of the present invention comprises a dielectric covering a foil electrode arranged along the lamp axis, and a discharge vessel fused to the dielectric to form a main discharge space. Furthermore, within the main discharge space, the foil electrode and the dielectric are partially sealed in the axial direction of the lamp, forming an auxiliary discharge space within the dielectric. "Sealed" here means that the foil electrode is fused to the dielectric in such a way that it is sealed (hermetically sealed).

[0008] In an excimer lamp that uniformly irradiates the entire main discharge space with ultraviolet light, when a starting auxiliary discharge space is formed throughout the inner tube, the input voltage in the normal (rated) lighting state is set to a value that takes into account the voltages of both the main discharge space and the starting auxiliary discharge space. This increases the voltage (power) required to light the lamp, impacting lamp durability and lifespan. The excimer lamp of the present invention achieves efficient lighting while minimizing power consumption during main discharge lighting.

[0009] The foil electrode is fused to the dielectric at at least one end in the longitudinal direction of the foil electrode, and the auxiliary discharge space can be formed between the surface of the foil electrode and the inner surface of the dielectric in such a manner that the electric field intensity varies along at least one of the lamp axial direction and the lamp circumferential direction.

[0010] For example, the foil electrode can be sealed to the dielectric in a region with low electric field intensity along at least one of the lamp axial direction and the lamp circumferential direction, and form the auxiliary discharge space in a region with high electric field intensity. This is achieved by separating the edge of the foil electrode from the inner surface of the dielectric in the auxiliary discharge space.

[0011] Alternatively, the foil electrode can be sealed to the dielectric in a region with high electric field intensity along at least one of the lamp axial direction and the lamp circumferential direction, and form the auxiliary discharge space in a region with low electric field intensity. This is accomplished by fusing the edge of the foil electrode to the dielectric in the auxiliary discharge space.

[0012] The discharge vessel may be configured such that the front end of the dielectric material penetrates a small-diameter portion provided at the front end of the discharge vessel, and the front end of the foil electrode, along the lamp axis, is located further rearward of the small-diameter portion. "Enclosed in the small-diameter portion" means that the front end of the front end is located closer to the bottom surface of the small-diameter portion than the lamp-center end of the small-diameter portion, along the vessel axis.

[0013] The auxiliary discharge space can be formed such that the distance between the dielectric and the foil electrode along the width direction of the foil electrode at the edge is shorter than the distance between the dielectric and the foil electrode along the width direction of the foil electrode at the center. Furthermore, the auxiliary discharge space can be formed such that the distance between the dielectric and the foil electrode along the length direction of the foil electrode at the end is shorter than the distance between the dielectric and the foil electrode along the length direction of the foil electrode at the center.

[0014] In a method for lighting an excimer lamp as one embodiment of the present invention, the excimer lamp comprises: an inner tube covering an inner electrode arranged along the axial direction of the lamp; and an outer tube fused to the expanded diameter portion of the inner tube to form a main discharge space between the outer tube and the inner tube, and an auxiliary discharge space formed between the surface of the inner electrode and the inner surface of the inner tube, so that a portion of light radiated from the auxiliary discharge space toward the axial direction of the lamp is irradiated into the main discharge space through the front end portion of the inner tube on the side opposite to each diameter portion and the expanded diameter portion.

[0015] A method for manufacturing an excimer lamp, one embodiment of the present invention, includes the following steps: inserting a foil-shaped inner electrode into a glass tube serving as an inner tube; sealing the inner tube by reducing the pressure inside the inner tube or by introducing a rare gas below atmospheric pressure into the inner tube; and heating and reducing the diameter of the inner tube, thereby partially sealing the inner tube and the inner electrode to form an auxiliary discharge space within at least a portion of the inner tube along the tube axis. For example, the main discharge space is formed by integrally heating and fusing the outer tube and the expanded diameter portion of the inner tube.

[0016] On the other hand, as another embodiment of an excimer lamp capable of improving lighting starting performance and achieving lamp lighting based on efficient main discharge, the following excimer lamp can be provided. Specifically, the excimer lamp of the present invention comprises: a first dielectric covering a foil-shaped electrode arranged along the lamp axis; a second dielectric covering the first dielectric; and a discharge vessel fused to the second dielectric to form a main discharge space. Furthermore, within the main discharge space, the first and second dielectrics are partially fused together in the lamp axis direction to form an auxiliary discharge space between the first and second dielectrics.

[0017] In an excimer lamp with a starting-assisting discharge space formed throughout the entire inner tube, ultraviolet light is irradiated from the main discharge space to the exterior of the lamp with uniform intensity. However, in ultraviolet irradiation devices and ozone generators equipped with excimer lamps, there are cases where it is desirable to generate a localized discharge state within the main discharge to suppress the ultraviolet intensity (illuminance) or the concentration of ozone generated. The present invention improves the lamp's ignition and starting performance while generating a desired discharge state within the main discharge space.

[0018] The first dielectric can be welded to the second dielectric at least at both ends in the longitudinal direction of the first dielectric, and the auxiliary discharge space can be formed between the outer surface of the first dielectric and the inner surface of the second dielectric in such a manner that the electric field intensity varies along at least one of the lamp axial direction and the lamp circumferential direction.

[0019] For example, the foil electrode can be fused to the first and second dielectric layers in regions of low electric field intensity along at least one of the lamp axial and lamp circumferential directions of the foil electrode, thereby forming an auxiliary discharge space in regions of high electric field intensity. In this case, the auxiliary discharge space can be formed between the outer surface portion of the first dielectric layer corresponding to the portion covering the edge of the foil electrode and the inner surface of the second dielectric layer.

[0020] Alternatively, the first dielectric can be fused to the second dielectric in a region of high electric field intensity along at least one of the lamp axial direction and the lamp circumferential direction of the foil electrode, thereby forming an auxiliary discharge space in a region of low electric field intensity. In this case, the auxiliary discharge space can be formed between the outer surface of the first dielectric corresponding to the portion covering the side surface of the foil electrode and the inner surface of the second dielectric.

[0021] The front end of the first dielectric and / or the second dielectric can be configured such that the front end of the front end portion enters the small-diameter portion provided at the front end of the discharge vessel, and the front end of the foil electrode along the lamp axis is located further rearward than the small-diameter portion. Here, "entering the small-diameter portion" means that the front end of the front end portion is located closer to the bottom surface of the small-diameter portion than the lamp-center end of the small-diameter portion along the vessel axis.

[0022] 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 at the edge is shorter than the distance between the first dielectric and the second dielectric along the width direction of the foil electrode at the center. Furthermore, 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 at the end is shorter than the distance between the first dielectric and the second dielectric along the length direction of the foil electrode at the center.

[0023] In a lighting method for an excimer lamp as another embodiment of the present invention, the excimer lamp includes: an inner tube composed of a first dielectric covering an inner electrode arranged along the lamp axis and a second dielectric covering the first dielectric; and an outer tube fused to an expanded diameter portion of the inner tube to form a main discharge space. Within the 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 in the axial direction of the lamp, and a portion of light radiated from the auxiliary discharge space toward the lamp axis is irradiated into the main discharge space through the front end portion and expanded diameter portion of the inner tube on the main discharge space side.

[0024] Another embodiment of the present invention includes a method for manufacturing an excimer lamp comprising the following steps: inserting an inner electrode into a glass tube serving as a cladding tube, or coating the inner electrode with a dielectric material serving as the cladding tube; inserting the cladding tube into the glass tube serving as the inner tube; sealing the inner tube by reducing the pressure inside the inner tube, or by enclosing a rare gas below atmospheric pressure into the inner tube; and heating and reducing the diameter of the inner tube, and partially fusing the inner tube to the cladding tube to form an auxiliary discharge space along the tube axis between the cladding tube and the inner tube. For example, the main discharge space is formed by integrally heating and fusing the expanded diameter portions of the outer tube and the inner tube.

[0025] On the other hand, as another embodiment of an excimer lamp capable of improving ignition start-up performance and achieving lamp ignition based on efficient main discharge, the following excimer lamp can be provided. Specifically, the excimer lamp of the present invention comprises: a dielectric covering a foil electrode arranged along the lamp axis; and a discharge vessel fused to the dielectric to form a main discharge space, the dielectric having an extension extending from an end of the discharge vessel. Furthermore, in the extension, the foil electrode and the dielectric are partially sealed to form an auxiliary discharge space inside the dielectric. Here, "sealed" means that the foil electrode is fused to the dielectric in a sealed (airtight) manner.

[0026] In excimer lamps with a starting aid discharge space formed throughout the entire inner tube, the main discharge space and the starting aid discharge space are concentrically arranged, which limits the size of the discharge tube. This can make it difficult to position the excimer lamp within the sleeve with a small gap. The present invention improves lamp ignition and startup performance and adapts to various operating environments.

[0027] The auxiliary discharge space can be formed between the surface of the inner electrode and the inner surface of the dielectric so that the electric field strength varies along at least one of the lamp axial direction and the lamp circumferential direction. For example, the electric field strength can be varied by varying the cross-sectional shape of the foil electrode, the manner in which the space near the boundary between the sealed portion of the foil electrode and the dielectric and the auxiliary discharge space is changed, and so on.

[0028] For example, the foil electrode can be formed so that its edge width is narrower than its center width (e.g., a knife-edge shape). In this case, the foil electrode edge can be separated from the inner surface of the dielectric in the auxiliary discharge space, thereby varying the electric field intensity along the lamp circumference. Alternatively, the foil electrode edge can be sealed to the dielectric in the auxiliary discharge space, thereby also varying the electric field intensity along the lamp axial direction near the aforementioned boundary.

[0029] The foil electrode may be composed of a single member or a plurality of foil electrodes. For example, the foil electrode may be composed of a first electrode portion disposed inside the discharge vessel and a second electrode portion electrically connected to the first foil electrode portion via a power supply line or the like and disposed inside the extension portion.

[0030] The discharge vessel may be configured such that, for example, the front end of the dielectric member enters a small diameter portion provided at the front end of the discharge vessel, and the front end of the foil electrode along the lamp axis is located further rearward than the small diameter portion.

[0031] The auxiliary discharge space can be formed such that the distance between the dielectric and the foil electrode along the width direction of the foil electrode at the edge is shorter than the distance between the dielectric and the foil electrode along the width direction of the foil electrode at the center. Furthermore, the auxiliary discharge space can be formed such that the distance between the dielectric and the foil electrode along the length direction of the foil electrode at the end is shorter than the distance between the dielectric and the foil electrode along the length direction of the foil electrode at the center.

[0032] In a method for lighting an excimer lamp as another embodiment of the present invention, an auxiliary discharge space is formed between the surface of the inner electrode and the inner surface of the inner tube in an extension portion extending from the expanded diameter portion of the inner tube toward the outside of the outer tube, and a portion of light radiated from the auxiliary discharge space toward the lamp axis passes through the front end portion and expanded diameter portion of the inner tube on the main discharge space side and is irradiated into the main discharge space.

[0033] A method for manufacturing an excimer lamp, which is another embodiment of the present invention, includes the following steps: inserting a foil-shaped inner electrode into a glass tube serving as an inner tube; sealing the inner tube by reducing the pressure inside the inner tube, or sealing a rare gas into the inner tube at a pressure below atmospheric pressure; heating the inner tube, reducing its diameter, and locally fusing the inner tube to the inner electrode to form an auxiliary discharge space in at least a portion of the inner tube along the tube axis; and inserting the inner tube into a glass tube serving as a discharge tube to fuse the outer tube to the inner tube in a manner such that a portion of the inner tube extends from the discharge tube.

[0034] According to the present invention, it is possible to provide an excimer lamp capable of improving lamp lighting starting performance and performing lamp lighting by efficient main discharge. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic cross-sectional view of the excimer lamp according to the first embodiment as viewed from the side.

[0036] Figure 2 This is a schematic cross-sectional view of the excimer lamp according to the first embodiment as viewed from the axial direction side.

[0037] Figure 3 This is a schematic cross-sectional view of the excimer lamp according to the second embodiment as viewed from the side.

[0038] Figure 4 This is a schematic cross-sectional view of the excimer lamp according to the second embodiment as viewed from the axial direction side.

[0039] Figure 5 This is a schematic cross-sectional view of the excimer lamp according to the third embodiment as viewed from the side.

[0040] Figure 6 This is a schematic cross-sectional view of the excimer lamp according to the third embodiment as viewed from the axial direction side.

[0041] Figure 7 This is a schematic cross-sectional view of the excimer lamp according to the fourth embodiment as viewed from the side.

[0042] Figure 8 This is a schematic cross-sectional view of the excimer lamp according to the fourth embodiment as viewed from the axial direction side.

[0043] Figure 9 This is a schematic cross-sectional view of an excimer lamp according to a fifth embodiment as viewed from the side.

[0044] Figure 10 This is a schematic cross-sectional view of an excimer lamp according to a fifth embodiment as viewed from the axial side.

[0045] Figure 11 This is a schematic cross-sectional view of an excimer lamp according to a sixth embodiment as viewed from a side surface along the width direction of a foil-shaped electrode.

[0046] Figure 12 This is a schematic cross-sectional view of an excimer lamp according to a sixth embodiment, as viewed from a side surface along the thickness direction of a foil-shaped electrode.

[0047] Figure 13 This is a schematic cross-sectional view of an excimer lamp according to a sixth embodiment as viewed from the side.

[0048] Figure 14 This is a schematic cross-sectional view of an excimer lamp according to a seventh embodiment as viewed from a side surface along the width direction of a foil-shaped electrode.

[0049] Figure 15 This is a schematic cross-sectional view of an excimer lamp according to a seventh embodiment, as viewed from a side surface along the thickness direction of a foil-shaped electrode.

[0050] Figure 16 This is a schematic cross-sectional view of an excimer lamp according to a seventh embodiment as viewed from the axial side.

[0051] Figure 17 This is a schematic cross-sectional view of an excimer lamp according to the eighth embodiment as viewed from the side.

[0052] Figure 18 This is a schematic cross-sectional view of an excimer lamp according to an eighth embodiment as viewed from the axial side.

[0053] Figure 19 This is a schematic cross-sectional view of an excimer lamp as a modified example of the eighth embodiment as viewed from the side.

[0054] Description of labels

[0055] 10: Excimer lamp; 20: Outer tube; 30: Inner electrode; 40: Outer electrode; 50: Inner tube (dielectric). DETAILED DESCRIPTION

[0056] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0057] Figure 1 This is a schematic cross-sectional view of the excimer lamp according to the first embodiment as viewed from the side. Figure 2 This is a schematic cross-sectional view of the excimer lamp according to the first embodiment as viewed from the axial direction side. Figure 2 Equivalent to following Figure 1 BB line cross-sectional view. In addition, Figure 1 The cross-sectional view is equivalent to the cross-sectional view along the Figure 2 A cross-sectional view of the line along the center axis of the lamp.

[0058] The excimer lamp 10 includes a discharge vessel 10T formed from an outer tube 20 and an inner tube 50, each made of a dielectric material such as quartz glass, each having a roughly cylindrical cross-section. A strip-shaped foil electrode (hereinafter referred to as the inner electrode) 30, extending along the tube diameter (hereinafter also referred to as the lamp radial direction), is encased in a columnar dielectric (hereinafter referred to as the inner tube) 50 along the tube axis (hereinafter also referred to as the lamp axis) C. The inner electrode 30 is not exposed in the annular discharge space (hereinafter referred to as the main discharge space) S1 formed between the outer tube 20 and the inner tube 50. The inner tube 50 is formed with a roughly circular cross-section. Alternatively, the inner electrode 30 may be embedded in the inner tube 50.

[0059] The inner tube 50 is coaxially arranged with the outer tube 20. The inner electrode 30 is coaxially arranged with the outer tube 20 so that its center position in the width and thickness directions is aligned with the lamp axis C. The inner electrode 30 is symmetrically arranged about the tube axis C. The outer tube 20 is integrally heat-fused to the expanded diameter portion 51 of the inner tube 50 at one end 20T2, thereby forming a discharge space (main discharge space) S1.

[0060] A rare gas such as xenon or a mixed gas of a rare gas and a halogen gas is filled in the main discharge space S1 as a discharge gas, and the pressure of the discharge gas is set to, for example, 5 kPa to 150 kPa.

[0061] The discharge vessel 10T has protruding projections (hereinafter referred to as small-diameter portions) 22 and 52 at both ends of a portion of a constant inner diameter portion (hereinafter referred to as a cylindrical portion) 20T0 surrounding the main discharge space S1. The small-diameter portion 52 represents a portion of the rear end of the inner tube 50 that extends beyond the end 20T2 of the outer tube 20 along the lamp axis C and is not covered by the outer tube 20. The power supply line 70 extends through the interior of this small-diameter portion 52.

[0062] The small-diameter portion 22 is formed during the lamp manufacturing process, protruding from the discharge vessel 10T (outer tube 20) toward the front end of the lamp along the lamp axis C. The front end of the outer tube 20 is heated and deformed to reduce its diameter, and an exhaust pipe having a smaller diameter than the outer tube 20 is welded to form the small-diameter portion 22 as an integral unit. The region that forms part of the lamp axial direction range of the discharge vessel 10T includes the small-diameter portion 22, which has a smaller outer and inner diameter than the range L along the lamp axial direction where the outer electrode 40 is disposed (axial arrangement range).

[0063] The tip portion of the end portion 50T1 of the inner tube 50 is positioned within the space of the small-diameter portion 22, and the end portion 50T1 of the inner tube 50 contacts the small-diameter portion 22. This ensures that the inner tube 50 is stably held coaxially within the outer tube 20. Furthermore, the outer surface of the end portion 50T1 of the inner tube 50 has a tapered convex curved surface, while the inner surface of the small-diameter portion 22 has a tapered concave curved surface. This prevents damage to the inner tube 50 and outer tube 20 due to dimensional errors caused by heat-molding, and maintains the inner tube 50 in a stable coaxial state. This fitted state prevents the tip portion 30T1 of the inner electrode 30 from entering the interior space of the small-diameter portion 22 along the lamp axis C, but rather from being positioned toward the rear end (center of the discharge vessel) of the small-diameter portion 22.

[0064] 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 a structure in which a linear electrode portion made of a conductive metal is wound along the surface of the outer tube 20, and is disposed so as to be spirally wound at predetermined intervals along the tube axis C.

[0065] The axial arrangement range L of the outer electrode 40 is set within the cylindrical portion 20T0, which is a portion of a constant inner diameter between the tapered ends 20T1 and 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 the end of the inner electrode 30 is connected to an external power supply unit (not shown), and power is supplied to the excimer lamp 10 via the power supply line 70.

[0066] By applying a high frequency (e.g., in the range of several kHz to several tens of MHz) and a high voltage (e.g., in the range of several kV to several dozen kV) to the inner and outer electrodes, excimer light is emitted from the discharge space S1. Here, ultraviolet light (e.g., with a wavelength of 172 nm) is emitted outside the discharge vessel. Therefore, the excimer lamp 10 can be used in ozone generating devices that perform sterilization and deodorization based on ozone generation, as well as in ultraviolet irradiation devices that directly irradiate ultraviolet light onto an object.

[0067] A discharge space S2 for assisting lighting startup (hereinafter referred to as an auxiliary discharge space) is formed between the inner electrode 30 and the inner tube 50. Figure 1 As shown, the inner electrode 30 has both axial end portions 30T1 and 30T2 welded (sealed) to the inner tube 50 over its entire circumference. Meanwhile, in the middle portion between the inner electrode 30's end portions 30T1 and 30T2, including the axial center of the discharge vessel 10T, only the radial edge portions 30T3 and 30T4 of the inner electrode 30 are welded to the inner tube 50. This forms an auxiliary discharge space S2.

[0068] Here, the range M of the auxiliary discharge space S2 along the lamp axis C (auxiliary discharge space range) is set to a portion shorter than the axial arrangement range L of the inner electrode 30 corresponding to the axial arrangement range L of the outer electrode 40 .

[0069] The auxiliary discharge space S2 is formed by the two side surfaces 30S1 and 30S2 of the foil-shaped inner electrode 30 (see Figure 2 ) The inner surfaces of the inner tubes 50 face each other and form two discharge space regions S2A and S2B. The cross-sectional shapes of the discharge space regions S2A and S2B are symmetrical about the inner electrode 30 and the lamp axis C.

[0070] In addition, the two edges 30T3 and 30T4 of the foil-shaped inner electrode 30 are blade-shaped. The inner electrode 30 is sharpened from the center in the width direction toward the edge (end), and its thickness becomes thinner than the thickness of the center in the width direction. The two edges 30T3 and 30T4 are sharp.

[0071] Therefore, in the radial cross-sectional shape of the lamp in the discharge space regions S2A and S2B, the length of the distance between the inner surface of the inner tube 50 and the surface of the inner electrode 30 along the thickness direction of the inner electrode 30 is longer than the length T2 of the distance near the two edges 30T3 and 30T4 of the inner electrode 30. The discharge space regions S2A and S2B become more tapered toward the two edges 30T3 and 30T4 of the inner electrode 30.

[0072] Furthermore, near the ends ST1 and ST2 of the inner tube 50 exposed to the inner surface of the auxiliary discharge space S2 (the ends of the auxiliary discharge space range M), the distance between the inner electrode 30 and the inner tube 50 gradually decreases, narrowing the discharge space region and becoming tapered toward the ends 30T1 and 30T2 of the inner electrode 30. Furthermore, the distances from the side surfaces 30S1 and 30S2 of the inner electrode 30 and the edges 30T3 and 30T4 of the inner electrode 30 gradually decrease, and the inner tube 50 is sealed to the inner electrode 30.

[0073] That is, the auxiliary discharge space S2 (discharge space regions S2A, S2B) narrows and becomes sharper toward the ends 30T1, 30T2 in the longitudinal direction (lamp axial direction) and the edges 30T3, 30T4 in the width direction (lamp radial direction) along the surface of the foil-shaped inner electrode 30.

[0074] The two end portions 30T1 and 30T2 of the inner electrode 30 are embedded in the inner tube 50 and in contact with each other, and are not exposed in the auxiliary discharge space S2. Furthermore, the two edge portions 30T3 and 30T4 of the inner electrode 30 are embedded in the inner tube 50 and in contact with each other throughout the entire range M of the auxiliary discharge space along the lamp axial direction, and are not exposed in the auxiliary discharge space S2. Therefore, the two discharge space regions S2A and S2B that constitute the auxiliary discharge space S2 are spatially separated by the inner electrode 30.

[0075] As described above, the edges 30T3 and 30T4 of the inner electrode 30 are knife-edge shaped, which results in electric field concentration near these edges. Similarly, electric field concentration also occurs near the ends 30T1 and 30T2 of the inner electrode 30. However, since the edges 30T3 and 30T4 and the ends 30T1 and 30T2 of the inner electrode 30 are not exposed in the auxiliary discharge space S2, the consumption caused by the discharge of the inner electrode 30 can be suppressed.

[0076] As will be described later, the auxiliary discharge space S2 is in a reduced pressure state below atmospheric pressure. In addition, a rare gas (at atmospheric pressure or lower) that reduces the voltage at the time of lighting startup may be sealed in the auxiliary discharge space S2.

[0077] When a high-frequency, high-voltage voltage is applied between the inner electrode 30 and the outer electrode 40, the auxiliary discharge space S2 is in a decompressed state. Therefore, a discharge occurs first in the auxiliary discharge space S2 at a lower ignition voltage than in the main discharge space S1. Then, a portion of the light (here, ultraviolet light) radiated radially from the auxiliary discharge space S2 passes through the inner tube 50 and reaches the main discharge space S1.

[0078] In addition, a portion of the light radiated toward the lamp axis due to the discharge generated in the auxiliary discharge space S2 is transmitted toward the end portions 50T1 and 50T2 through the optical fiber effect (an effect based on the same principle as that of optical fibers used in communication circuits) caused by repeated reflections within the tube wall of the inner tube 50 (the boundary surface of the tube wall).

[0079] Here, a portion of the end 50T1 of the inner tube 50 enters and contacts the small-diameter portion 22, and an expanded-diameter portion 51 is formed on the end 50T2 side of the inner tube 50. Therefore, ultraviolet light introduced into the ends 50T1 and 50T2 by the fiber optic effect passes through the end 50T1 of the inner tube 50 and the expanded-diameter portion 51 and irradiates the main discharge space S1 from the ends 20T1 and 20T2 of the outer tube 20. This generates a discharge in the main discharge space S1.

[0080] Thus, the auxiliary discharge space S2 locally formed within the inner tube 50 can improve lighting startup performance. Meanwhile, the auxiliary discharge space S2 only needs to be small enough for the radiated light to reach the main discharge space S1. Therefore, it does not occupy the majority of the space inside the inner tube 50, but is instead formed as a localized discharge space. Therefore, during the period of main discharge generation and lamp lighting, the voltage applied between the inner electrode 30 and the outer electrode 40 can be suppressed, and the required power can be reduced, thereby improving lamp durability and life.

[0081] The illuminance distribution (light distribution) along the outer circumference of the discharge vessel varies depending on the shape of the discharge vessel and the location of the discharge generated within it. Furthermore, the discharge state is affected by the positional relationship between the electrodes (anode and cathode) and the electric field intensity distribution determined by the shapes of the cladding tube, inner tube, and auxiliary discharge space. However, the excimer lamp 10 described above does not change the shape or discharge state of existing double-tube excimer lamps. Therefore, in ultraviolet irradiation devices and ozone generators, it is possible to improve lighting startup performance without affecting lamp characteristics such as the discharge maintenance voltage and illuminance distribution, or the characteristics of a power supply suitable for these lamp characteristics.

[0082] Ignition start-up performance can be measured by measuring the reliability (probability [%) of achieving a stable ignition state, where the desired emission spectrum is obtained from the discharge within the discharge vessel, when voltage is applied to the excimer lamp. Excimer lamps require reliable ignition start-up performance (100% reliability) even in low-temperature conditions, darkness, and after prolonged periods of inactivity. However, this embodiment reliably achieves a stable ignition state without requiring a large ignition power supply or auxiliary starting light source, effectively achieving 100% ignition start-up reliability.

[0083] The two discharge space regions S2A and S2B, which are spatially separated from each other, of the auxiliary discharge space S2 are formed by embedding the regions of relatively high electric field intensity near the edges 30T3 and 30T4 and the ends 30T1 and 30T2 of the inner electrode 30 in the inner tube 50. Therefore, when a high-frequency high voltage is applied between the inner electrode 30 and the outer electrode 40, a discharge space is formed in the region of relatively low electric field intensity in the circumferential and axial directions of the lamp.

[0084] However, since the auxiliary discharge space S2 is in a decompressed state, discharge is more likely to occur at a lower lighting starting voltage, making it easier for discharge to occur in the high-field-strength region of the main discharge space S1, leading to a transition to stable (rated) lighting. In this way, a stable lighting state can be achieved by generating an auxiliary discharge in the auxiliary discharge space with a lower electric field strength and then transitioning to a main discharge in the main discharge space with a higher electric field strength.

[0085] Meanwhile, the auxiliary discharge space S2 has a substantially uniform cross-sectional shape in the lamp radial direction along the lamp axis C, and the electric field intensity does not vary along the lamp axis C. Therefore, ultraviolet rays irradiated from the discharge vessel 10T to the outside of the lamp can have a uniform illumination distribution along the lamp axis C.

[0086] The excimer lamp 10 can be manufactured, for example, through the following manufacturing steps.

[0087] A glass tube (inner tube) with a cylindrical cross-section, serving as a covering for a foil-shaped electrode (inner electrode), is formed from a dielectric material that is transparent to light emitted by the discharge formed in the auxiliary discharge space. After forming the inner tube, a power supply line is connected to the foil-shaped electrode by resistance welding or other means, and the foil-shaped electrode is inserted into the bottomed cylindrical glass tube. After the foil-shaped electrode is inserted, the interior of the glass tube is brought to a reduced pressure (vacuum) and sealed. At this point, a rare gas below atmospheric pressure may be introduced into the glass tube.

[0088] The glass tube is heated while rotating, causing it to soften and shrink (reduce in diameter). At this point, only the inner circumference of the glass tube is in close contact with the edge of the foil electrode along its width (tube diameter). Then, while the edge of the foil electrode is embedded in the glass tube, heating (shrinkage) is stopped, preventing the edge of the foil electrode from being exposed. This creates a non-contact space between the glass tube and the foil electrode, forming an auxiliary discharge space.

[0089] Furthermore, an auxiliary discharge space is formed, and a flange-shaped (so-called abacus bead-shaped) enlarged portion is formed at one end of the glass tube. Alternatively, instead of rotating the glass tube, only the portion of the glass tube facing the edge of the foil electrode can be heated axially to achieve close contact. By sealing the entire circumference of the foil electrode's end along the longitudinal direction (tube axis), the foil electrode's end is embedded in the glass tube and does not protrude into the auxiliary discharge space.

[0090] The outer tube is formed by reducing the diameter of one end of a quartz tube that is transparent to the wavelength of ultraviolet rays emitted from the main discharge space, providing an open inlet tube (exhaust tube), and leaving the end side of the portion that seals with the enlarged diameter portion of the inner tube open.

[0091] The inner tube is then inserted into the outer tube, coaxially arranged, and heat-fused at the sealing portion to form the discharge tube. Afterwards, the inlet tube is evacuated to remove impurities, discharge gas is introduced into the tube, and the inlet tube is hermetically sealed by heat-fusion. Finally, the outer electrode is applied to the outer surface of the outer tube.

[0092] Next, use Figure 3 and Figure 4 Next, an excimer lamp according to a second embodiment will be described. In the second embodiment, an auxiliary discharge space is provided in the center of the lamp.

[0093] Figure 3 This is a schematic cross-sectional view of an excimer lamp according to a second embodiment as viewed from the side. Figure 4 This is a schematic cross-sectional view of an excimer lamp according to a second embodiment as viewed from the axial direction side.

[0094] In the second embodiment, the auxiliary discharge space S2 is formed within the auxiliary discharge space range M in the middle of the discharge vessel 10T, that is, the middle portion including the axial center of the lamp. Therefore, portions of the edges 30T3 and 30T4 of the inner electrode 30 are exposed in the auxiliary discharge space S2, forming a spatial region with high electric field intensity in the vicinity thereof.

[0095] Furthermore, near the axial center of the lamp, the entire circumference of the inner electrode 30 is exposed, forming an auxiliary discharge space S2 that surrounds the entire circumference of the inner electrode 30. Meanwhile, the inner electrode 30 is sealed to the inner tube 50 along its entire circumference at both axial ends 30T1 and 30T2. The auxiliary discharge space S2 has an area (auxiliary discharge space area) M along the lamp axis C that corresponds to a portion of the axial arrangement range L of the outer electrode 40. Furthermore, within the auxiliary discharge space area M, the outer diameter of the inner tube 50 is larger than within the other areas, and the distance between the outer surface of the inner tube 50 and the inner surface of the outer tube 20 is smaller.

[0096] Near the ends ST1 and ST2 of the inner surface of the inner tube 50 exposed to the auxiliary discharge space S2, the distance between the inner electrode 30 and the inner tube 50 gradually decreases, narrowing the space. The discharge space tapers toward the ends 50T1 and 50T2 of the inner tube 50. Furthermore, the distances between the side surfaces 30S1 and 30S2 of the inner electrode 30 and the edges 30T3 and 30T4 of the inner electrode 30 gradually decrease, and the inner tube 50 is sealed to the inner electrode 30. The outer diameter of the inner tube 50 also gradually decreases, forming a smoothly curved outer surface.

[0097] Therefore, near the two end portions ST1 and ST2 of the inner surface of the inner tube 50 exposed in the auxiliary discharge space S2, two discharge space regions are formed so as to be spatially partitioned in the circumferential direction by the inner electrode 30, as in the first embodiment. However, near the center portion of the auxiliary discharge space S2 (auxiliary discharge interval M), a discharge space region is formed that is spatially connected so as to surround the entire circumference of the inner electrode 30.

[0098] like Figure 3 As shown, the spatial shape of the auxiliary discharge space S2 increases in radial cross-sectional area as it approaches the center of the lamp (auxiliary discharge space range M), and decreases in radial cross-sectional area as it approaches the small-diameter portions 22 and 52 at either end of the discharge vessel 10T. Therefore, the distance L1 between the two edges 30T3 and 30T4 of the inner electrode 30 in the center portion of the auxiliary discharge space S2 along the lamp axis C and the inner circumferential surface of the inner tube 50 is longer than the distance L2 near the two ends ST1 and ST2 of the inner tube 50 exposed in the inner surface of the auxiliary discharge space S2.

[0099] In addition, if Figure 4 As shown in FIG. 1 , the closer the auxiliary discharge space S2 is to the center of the inner electrode 30 in the width direction (lamp radial direction), the larger the radial cross-sectional area is. The length of the distance between the inner surface of the inner tube 50 and the surface of the inner electrode 30 along the lamp radial direction is equal to the length T2 of the distance between the two edges 30T3 and 30T4 of the inner electrode 30 along the width direction (equivalent to Figure 3 Compared with L1), the length T1 of the spacing distance along the thickness direction near the center (lamp center axis) is longer.

[0100] That is, the auxiliary discharge space S2 has a structure in which the space area narrows toward the ends 30T1 and 30T2 in the longitudinal direction (lamp axial direction) and the edges 30T3 and 30T4 in the width direction (lamp radial direction) of the foil-shaped inner electrode 30 .

[0101] The ends 30T1 and 30T2 of the inner electrode 30 are largely buried in the inner tube 50, while the edges 30T3 and 30T4 of the inner electrode 30 are partially exposed in the auxiliary discharge space S2. This creates a spatial region with a high electric field intensity within the decompressed auxiliary discharge space S2. This allows discharge to occur primarily in the auxiliary discharge space S2 using a lower ignition starting voltage than in the main discharge space S1. Furthermore, the power required for lamp ignition can be reduced, thereby suppressing power consumption caused by discharge from the inner electrode 30 (particularly the edges).

[0102] On the other hand, the central portion of the auxiliary discharge space S2 is formed as a discharge space region surrounded by the inner surface of the inner tube 50, which covers the entire circumference of the lamp axial range where the two side surfaces 30S1 and 30S2 of the inner electrode 30 are exposed. In addition, near the two end portions ST1 and ST2 of the inner tube 50 exposed in the inner surface of the auxiliary discharge space S2, a discharge space region is formed in which the inner electrode 30 is sandwiched and opposed to each other, as in the first embodiment. The distance between the inner tube 50 and the inner electrode 30 is reduced, thereby ultimately sealing the entire circumference.

[0103] This configuration allows ultraviolet radiation to be emitted throughout the discharge space S1, thereby achieving a stable main discharge in the discharge space S1. Meanwhile, the auxiliary discharge space S2 is configured to extend over a portion of the axial arrangement range of the inner electrode 30 so that the electric field intensity is substantially uniform along the lamp axis C. Consequently, the ultraviolet radiation emitted from the discharge vessel 10T to the outside of the lamp can have a uniform illumination distribution along the lamp axis C.

[0104] Furthermore, the change in the spatial area of ​​the auxiliary discharge space S2 is gradual, meaning that the shape of the inner surface of the inner tube 50 changes smoothly. This improves the stability of lamp intensity, which is affected by stress concentration on the curved surface. Therefore, even if the inner tube 50 degrades (becomes embrittled) due to high-energy ultraviolet rays generated by the main discharge passing through the discharge space S1, damage to the discharge vessel 10T starting from the portion covering the auxiliary discharge space S2 can be suppressed. Alternatively, as in the first embodiment, the inner surface of the inner tube 50 may be brought into contact with the edge of the surface of the inner electrode 30.

[0105] The excimer lamp 10 can be manufactured using the same manufacturing process as the first embodiment. In the second embodiment, the inner tube, into which the inner electrode is inserted and coated, is heated to reduce its diameter. Heating is then stopped at a predetermined timing to form the auxiliary discharge space S2 in the center of the inner tube. For example, by not heating (reducing heating) the axial region corresponding to the auxiliary discharge space M, the diameter reduction caused by softening of the glass tube is suppressed (stopped), thereby forming the auxiliary discharge space. The inner surface of the inner tube 50 and the surface (particularly the edge) of the inner electrode 30 may also be in contact.

[0106] Next, use Figure 5 and Figure 6 An excimer lamp according to a third embodiment will be described. In the third embodiment, an auxiliary discharge space is formed at the end of the discharge container (inner tube).

[0107] Figure 5 This is a schematic cross-sectional view of the excimer lamp according to the third embodiment as viewed from the side. Figure 6This is a schematic cross-sectional view of the excimer lamp according to the third embodiment as viewed from the axial direction side.

[0108] In the third embodiment, the auxiliary discharge space S2 is formed in the auxiliary discharge space range M at the front end of the discharge vessel 10T, that is, in the vicinity of one end 50T1 of the inner tube 50 along the lamp axis C. Therefore, one (front end) end 30T1 and a portion of both edges 30T3 and 30T4 of the inner electrode 30 (that is, the vicinity of the inner electrode portion including the corner where both edges 30T3 and 30T4 of the inner electrode 30 intersect with the end 30T1) are exposed in the auxiliary discharge space S2, forming a spatial region with a high electric field intensity in the vicinity thereof.

[0109] Furthermore, the end surface 30E of the inner electrode 30 corresponds to the position in the auxiliary discharge space S2 at the greatest distance from the inner surface of the end portion 50T1 of the inner tube 50. Therefore, even when a conductive member having the same potential as that of the outer electrode (grounded) is disposed near the end portion 50T1 of the inner tube 50, a spatial region having a high electric field intensity is not formed near the end portion 50T1 of the inner tube 50, thereby suppressing abnormal discharge near the end portion 20T1 of the outer tube 20.

[0110] For example, the distance between the front end portion (corner) of the end surface 30E of the inner electrode 30 and the bottom of the inner surface of the inner tube 50 along the lamp axis C may be maximized. On the other hand, the other (rear end) end portion 30T2 of the inner electrode 30, which includes the center of the lamp axis, is sealed to the inner tube 50 over its entire circumference.

[0111] Here, the range M of the auxiliary discharge space S2 along the lamp axis C (auxiliary discharge space range) includes a portion of the axial arrangement range of the inner electrode 30, which corresponds to the axial arrangement range L of the outer electrode 40. Meanwhile, the auxiliary discharge space range M extends toward the front end of the lamp, with a portion thereof being defined as a section protruding beyond the end 30T1 of the inner electrode 30. By preventing a spatial region with high electric field intensity from forming near the end 50T2 of the inner tube 50, abnormal discharge near the end 20T2 of the outer tube 20 can be suppressed. Furthermore, in the auxiliary discharge space range M, the outer diameter of the inner tube 50 is larger than in other ranges, and the distance between the outer surface of the inner tube 50 and the inner surface of the outer tube 20 is smaller.

[0112] The auxiliary discharge space S2 is provided so as to protrude toward the small-diameter portion 22 from the spatial region where the outer electrode 40 and the inner electrode 30 face each other in the lamp radial direction to the spatial region where they do not face each other. The inner surface of the end portion 50T1 of the inner tube 50 forming the auxiliary discharge space S2 has a tapered, convex curved surface, which fits into the inner surface of the small-diameter portion 22. Meanwhile, the position of the front end portion 30T1 of the inner electrode 30 along the lamp axis C does not enter the interior space of the small-diameter portion 22 but is located closer to the rear end (center of the discharge vessel) than the small-diameter portion 22.

[0113] like Figure 5 As shown, the spatial shape of the auxiliary discharge space S2 increases in radial cross-section as it approaches the center of the auxiliary discharge space S2, and decreases in radial cross-section as it approaches the smaller diameter portions 22 and 52 at either end of the discharge vessel 10T. Therefore, the distance L1 between the edges 30T3 and 30T4 of the end surface 30E of the inner electrode 30 and the inner surface of the inner tube 50 along the lamp radial direction of the inner electrode 30 is longer than the distance L2 between the end ST2 of the inner tube 50, where it protrudes from the inner surface of the auxiliary discharge space S2. Similarly, the outer diameter of the inner tube 50 gradually decreases, forming a smoothly curved outer surface.

[0114] In addition, if Figure 6 As shown in FIG. 1 , the closer the auxiliary discharge space S2 is to the center of the width direction (lamp radial direction) of the inner electrode 30, the wider the radial cross-sectional area becomes. Therefore, with respect to the distance between the inner surface of the inner tube 50 and the surface of the inner electrode 30 along the lamp radial direction, the distance between the inner surface of the inner tube 50 and the surface of the inner electrode 30 along the lamp radial direction is greater than the distance between the edges 30T3 and 30T4 of the inner electrode 30 along the width direction (T1, which is equivalent to the distance between the sides 30S1 and 30S2 of the inner electrode 30 along the thickness direction). Figure 5 Therefore, the auxiliary discharge space S2 becomes narrower toward the two edge portions 30T3 and 30T4 of the inner electrode 30.

[0115] That is, the auxiliary discharge space S2 narrows toward the ends 30T1 and 30T2 in the longitudinal direction (lamp axial direction) and the edges 30T3 and 30T4 in the width direction (lamp radial direction) along the surface of the foil-shaped inner electrode 30 .

[0116] The end portion 30T2 of the inner electrode 30 on the rear end side including the center in the lamp axis direction is mostly buried in contact with the inner tube 50. Furthermore, the end portion 30T1 on the front end side of the inner electrode 30 and a portion of the front ends of both edges 30T3 and 30T4, that is, the vicinity of the front end portion of the inner electrode including the corner where both edges 30T3 and 30T4 of the inner electrode 30 intersect with the end portion 30T1, are exposed to the auxiliary discharge space S2.

[0117] In the auxiliary discharge space S2 in the decompressed state, a spatial region with a high electric field intensity is formed near the end portion 20T1 on the front end side of the discharge vessel 20T. Therefore, discharge can occur in the auxiliary discharge space S2 before that in the main discharge space S1, and a low lighting starting voltage can be set, thereby suppressing abnormal discharge on the end portion 20T1 side.

[0118] Furthermore, since the auxiliary discharge space S2 is formed near the boundary of the axial arrangement range L of the outer electrode 40, power consumption can be suppressed even during lamp operation, and power consumption caused by discharge from the inner electrode 30 (particularly the corner at the front end) can be suppressed. Alternatively, as in the first embodiment, the inner surface of the inner tube 50 may be brought into contact with the surface (particularly the edge) of the inner electrode 30.

[0119] On the other hand, as described above, the majority of the front end ST1 of the auxiliary discharge space section S2, which includes the center of the lamp axis, forms a discharge space region in which both side surfaces 30S1 and 30S2 of the inner electrode 30 are exposed, covering the entire circumference of the inner electrode 30 within the lamp axis, and surrounded by the inner surface of the inner tube 50. Simultaneously, near the rear end ST2 of the auxiliary discharge space section S2, a discharge space region is formed in which the inner electrode 30 is sandwiched and opposed, as in the first embodiment, and the distance between the inner tube 50 and the inner electrode 30 is reduced, ultimately sealing the entire circumference.

[0120] This configuration allows ultraviolet radiation to be emitted throughout the discharge space S1, thereby achieving a stable main discharge in the discharge space S1. Meanwhile, the auxiliary discharge space S2 is configured to extend over a portion of the axial arrangement range of the inner electrode 30 so that the electric field intensity is substantially uniform along the lamp axis C. Consequently, the ultraviolet radiation emitted from the discharge vessel 10T to the outside of the lamp can have a uniform illumination distribution along the lamp axis C.

[0121] Furthermore, the change in the spatial area of ​​the auxiliary discharge space S2 is gradual, meaning that the inner surface shape of the inner tube 50 changes smoothly, improving the stability of the curved lamp intensity. Therefore, even if the inner tube 50 deteriorates (becomes embrittled) due to high-energy ultraviolet rays generated by the main discharge passing through the discharge space S1, damage to the discharge vessel 10T starting from the portion covering the auxiliary discharge space S2 can be suppressed.

[0122] Such an excimer lamp 10 can be manufactured using the same manufacturing process as the first and second embodiments. In the third embodiment, the inner tube 50 is coated with an inner electrode and heated to reduce its diameter. Heating is then stopped at a predetermined timing to form the auxiliary discharge space S2 near the end 20T1 of the outer tube 20. For example, by not heating (reducing heating) the axial region corresponding to the auxiliary discharge space M, the diameter reduction caused by softening of the glass tube is suppressed (stopped), thereby forming the auxiliary discharge space. The inner surface of the inner tube 50 may also be in contact with the surface (particularly the edge) of the inner electrode 30.

[0123] In the second and third embodiments, the auxiliary discharge space S2 is formed locally along the lamp axis C. However, the auxiliary discharge space S2 may be formed to surround the inner electrode 30 over the entire circumferential range in accordance with the axial arrangement range L of the outer electrode 40 .

[0124] use Figure 7 、 Figure 8 An excimer lamp according to a fourth embodiment will be described. In the fourth embodiment, an auxiliary discharge space S2 is formed to surround the inner electrode 30 over the entire circumferential range in accordance with the axial arrangement range L of the outer electrode 40 .

[0125] Figure 7 This is a schematic cross-sectional view of an excimer lamp according to a fourth embodiment as viewed from the side. Figure 8 This is a schematic cross-sectional view of an excimer lamp according to a fourth embodiment as viewed from the axial direction side.

[0126] In the fourth embodiment, the auxiliary discharge space S2 has an auxiliary discharge space range M along the lamp axis that is slightly shorter than the axial arrangement range L of the outer electrode 40. Therefore, similarly to the second embodiment, the inner electrode 30 is entirely circumferentially sealed near its two end portions 30T1 and 30T2 and embedded within the inner tube 50. In contrast, the entire circumference of the inner electrode 30 is exposed in the middle portion of the inner electrode 30, which includes the axial center of the inner electrode 30, forming the auxiliary discharge space S2 so as to surround the entire circumference of the inner electrode 30.

[0127] The range of the auxiliary discharge space S2 can be adjusted appropriately based on the lamp specifications. For example, the axial range M of the auxiliary discharge space S2 can be set asymmetrically relative to the center of the lamp. The inner surface of the inner tube 50 and the surface (particularly the edge) of the inner electrode 30 can also be in contact.

[0128] The excimer lamp 10 can be manufactured using the same manufacturing process as the second embodiment. For example, by heating only the vicinity of the two end portions 30T1 and 30T2 of the inner electrode 30, and not heating (reduced heating) the axial region corresponding to the auxiliary discharge space M, the shrinkage of the glass tube caused by softening can be suppressed (stopped), thereby forming the auxiliary discharge space. The inner surface of the inner tube 50 and the surface (particularly the edge) of the inner electrode 30 can be in contact, or the inner tube can be heated after the inner electrode is inserted to prevent the inner electrode from moving.

[0129] 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. Furthermore, the light emitted from the auxiliary discharge space is not limited to ultraviolet light, but may also be visible light.

[0130] Next, use Figure 9 、 Figure 10 An excimer lamp according to a fifth embodiment will be described.

[0131] Figure 9 This is a schematic cross-sectional view of an excimer lamp according to a fifth embodiment as viewed from the side. Figure 10 This is a schematic cross-sectional view of an excimer lamp according to a fifth embodiment as viewed from the axial side. Figure 10 Equivalent to following Figure 9 BB line cross-sectional view. In addition, Figure 9 The cross-sectional view is equivalent to the cross-sectional view along the Figure 10 A cross-sectional view of the line along the center axis of the lamp.

[0132] The excimer lamp 1000 includes an outer tube 1020, made of a dielectric material such as quartz glass, with a roughly cylindrical cross-section. A columnar (membrane-like) first dielectric (hereinafter referred to as a cladding tube) 1050 is coaxially disposed within the outer tube 1020, along with a cylindrical second dielectric (hereinafter referred to as an inner tube) 1060, which covers the cladding tube 1050. The cladding tube 1050 has a width along the radial direction (hereinafter referred to as the lamp radial direction) and covers a strip-shaped foil electrode (hereinafter referred to as the inner electrode) 1030. The inner tube 1060, which covers the cladding tube 1050, is fused to a portion of the axial direction of the cladding tube 1050 and extends along the lamp axis C.

[0133] The covering tube 1050 and the inner tube 1060 are coaxially arranged relative to the outer tube 1020. The inner electrode 1030 is coaxially arranged relative to the outer tube 1020 so that its center position in the width and thickness directions is aligned with the lamp axis C. The inner electrode 1030 is symmetrically arranged about the tube axis C. The outer tube 1020 is integrally heat-fused at one end 1020T2 to the expanded diameter portion 1061 of the inner tube 1060. This forms a discharge space (main discharge space) S1.

[0134] A rare gas such as xenon or a mixed gas of a rare gas and a halogen gas is filled in the main discharge space S1 as a discharge gas, and the pressure of the discharge gas is set to, for example, 5 kPa to 150 kPa.

[0135] The discharge vessel 1000T is provided with protruding portions (hereinafter referred to as small-diameter portions) 1022 and 1062 at both ends of a portion of the inner diameter portion 1020T0 (hereinafter referred to as the cylindrical portion) surrounding the main discharge space S1. The small-diameter portion 1062, which is a portion of the rear end of the inner tube 1060 and is not covered by the outer tube 1020, protrudes toward the rear end of the lamp along the lamp axis C. The covering tube 1050, which covers the power supply wire 1070, extends through the interior of the small-diameter portion 1062, with the small-diameter portion 1052 of the covering tube 1050 protruding. Alternatively, the small-diameter portion 1062 of the inner tube 1060 can be used to cover the power supply wire 1070, so that the covering tube 1050 is not exposed at the end.

[0136] The small-diameter portion 1022 of the discharge tube 1000T is formed during the lamp manufacturing process, protruding from the discharge vessel 1000T (outer tube 1020) toward the front end of the lamp along the lamp axis C. The front end of the outer tube 1020 is heated and deformed to reduce its diameter, and an exhaust pipe with a smaller diameter than the outer tube 1020 is welded. As a result, the small-diameter portion 1022, which has a smaller diameter than the area L along the lamp axial direction where the outer electrode 1040 is disposed (axial arrangement area), is integrally formed within a portion of the discharge vessel 1000T's axial extent. Alternatively, the exhaust pipe used in lamp manufacturing may be positioned at a different location from the small-diameter portion.

[0137] The end 1050T1 of the covering tube 1050 enters the small-diameter portion 1022 and contacts the small-diameter portion 1022. Consequently, the covering tube 1050 is stably maintained coaxially within the outer tube 1020. In particular, the end 1050T1 of the covering tube 1050 forms a tapered convex curved surface on the outer surface, while the inner surface of the small-diameter portion 1022 of the discharge vessel 1000T forms a tapered concave curved surface. This ensures that the covering tube 1050 is stably maintained coaxially with the discharge vessel 1000T and is protected from damage even by dimensional errors caused by thermoforming.

[0138] Alternatively, a configuration may be employed in which the distal end portion 1060T1 of the inner tube 1060 enters the small-diameter portion 1022. In this case, the inner tube 1060 can be formed into a cylindrical bottom shape so as to cover the distal end portion 1050T1 of the covering tube 1050. Even in such a fitted state, the distal end portion 1030T1 of the inner electrode 1030, along the lamp axis C, does not enter the interior space of the small-diameter portion 1022 and is positioned toward the rear end (center of the discharge vessel) of the small-diameter portion 1022.

[0139] An electrode (hereinafter referred to as the outer electrode) 1040 is disposed on the outer surface 1020S of the outer tube 1020. The outer electrode 1040 is configured by winding a linear electrode portion made of a conductive metal along the surface of the outer tube 1020, and is spirally wound at predetermined intervals along the tube axis C.

[0140] The axial arrangement range L of the outer electrode 1040 is set to the cylindrical portion 1020T0, which is a portion of a constant inner diameter between the tapered ends 1020T1 and 1020T2 of the outer tube 1020. The axial length of the inner electrode 1030 corresponds to the axial arrangement range L of the outer electrode 1040. A power supply line 1070 connected to the end of the inner electrode 1030 is connected to an external power supply unit (not shown), and power is supplied to the excimer lamp 1000 via the power supply line 1070.

[0141] By applying a high frequency (e.g., several kHz to tens of MHz) and a high voltage (e.g., several kV to more than ten kV) to the inner and outer electrodes, excimer light is emitted from the discharge space S1. Here, ultraviolet light (e.g., with a wavelength of 172 nm) is emitted outside the discharge vessel. Therefore, the excimer lamp 1000 can be used in ozone generators that perform sterilization and deodorization based on ozone generation, as well as in ultraviolet irradiation devices that directly irradiate objects with ultraviolet light.

[0142] A discharge space S2 for assisting lighting startup (hereinafter referred to as an auxiliary discharge space) is formed between the covering tube 1050 and the inner tube 1060. Figure 9 and Figure 10 As shown, the inner electrode 1030 is sealed (closely attached) to the inner tube 1060 along the entire circumference of the lamp axis C and along the entire circumference of the inner electrode 1030. Furthermore, the cross-sectional shape of the cladding tube 1050 is generally elliptical, while the cross-sectional shape of the inner tube 60 is generally circular. An annular main discharge space S1 is formed between the inner tube 1060 and the outer tube 1020, and an auxiliary discharge space S2 is formed between the outer surface of the cladding tube 1050 and the inner surface of the inner tube 1060.

[0143] The auxiliary discharge space S2's auxiliary discharge space range (auxiliary discharge range) M along the lamp axis is slightly shorter than the axial arrangement range L of the outer electrode 40. Therefore, near the ends 1030T1 and 1030T2 of the inner electrode 1030, the outer circumference of the covering tube 1050 and the inner circumference of the inner tube 1060 are sealed across their entire circumference. In contrast, in the middle portion of the inner electrode 1030, which includes the axial center of the lamp, the entire outer circumference of the covering tube 1050 is exposed, surrounding the covering tube 1050 and forming the auxiliary discharge space S2. Furthermore, within the auxiliary discharge space range M, the outer diameter of the inner tube 1060 is larger than in other ranges, and the distance between the outer surface of the inner tube 1060 and the inner surface of the outer tube 1020 is smaller.

[0144] At the two ends ST1 and ST2 of the inner tube 1060 exposed within the auxiliary discharge space S2 (the two ends of the auxiliary discharge space range M), the distance between the cladding tube 1050 and the inner tube 1060 gradually decreases, and the discharge space narrows as the area nears the ends 1060T1 and 1060T2 of the inner tube 1060. Furthermore, the distance between the inner surface of the inner tube 1060 and the outer surface of the cladding tube 1050 gradually decreases, and the inner tube 1060 and the cladding tube 1050 are welded together. The outer diameter of the inner tube 1060 also gradually decreases, forming a smooth curved outer surface.

[0145] like Figure 9 As shown, the auxiliary discharge space S2 has a radial cross-sectional area that widens toward the center of the lamp (auxiliary discharge space range M) and narrows toward the smaller diameter portions 1022 and 1052 at either end of the discharge vessel 1000T. Therefore, the distance L1 between the outer circumferential surface of the cladding tube 1050 and the inner circumferential surface of the inner tube 1060 in the center portion of the auxiliary discharge space S2 along the lamp axis C is longer than the distance L2 between the inner tube 1060 at the two end portions ST1 and ST2 where the inner tube 1060 protrudes into the inner surface of the auxiliary discharge space S2.

[0146] Furthermore, the two edges 1030T3 and 1030T4 of the foil-like inner electrode 1030 are blade-shaped. The inner electrode 30 is tapered from the center in the width direction toward the edges (ends), and its thickness decreases compared to the thickness at the center in the width direction. The two edges 1030T3 and 1030T4 are sharp. The radial cross-section of the inner tube covering the foil-like inner electrode 1030 is short in the thickness direction of the foil-like inner electrode 1030 (minor axis direction), and its major axis direction is defined along the width direction.

[0147] Therefore, if Figure 9As shown in FIG. 1 , the closer the auxiliary discharge space S2 is to the center of the width direction (lamp radial direction) of the inner electrode 1030, the wider the radial cross-sectional area. Therefore, the length of the distance between the inner surface of the inner tube 1060 and the outer surface of the covering tube 1050 along the lamp radial direction is equal to the length T2 of the distance between the two edges 1030T3 and 1030T4 of the inner electrode 1030 along the width direction (equivalent to Figure 9 Compared with L1), the length T1 of the spacing distance along the thickness direction near the center (lamp center axis) is longer and becomes narrower toward the two edge portions 1030T3 and 1030T4 of the inner electrode 1030.

[0148] The auxiliary discharge space S2 is tapered with respect to the ends 1030T1 and 1030T2 in the longitudinal direction (lamp axial direction) and the edges 1030T3 and 1030T4 in the width direction (lamp radial direction) along the surface of the foil-shaped inner electrode 1030 .

[0149] Thus, the excimer lamp 1000 of this embodiment has a triple-structure discharge vessel 1000T, in which the covering tube 1050 and the inner tube 1060 are coaxially arranged relative to the outer tube 1020, forming a main discharge space S1 and an auxiliary discharge space S2. This allows the auxiliary discharge space S2 to be formed without significantly altering the external shape of conventional double-tube excimer lamps. Furthermore, by forming the covering tube in a film-like shape, the external shape can be made the same as that of conventional double-tube excimer lamps.

[0150] As described above, the edges 1030T3 and 1030T4 of the inner electrode 1030 are knife-edge shaped, resulting in electric field concentration near these edges. Meanwhile, because the covering tube 1050 has an elliptical cross-section, the electric field strength in the auxiliary discharge space S2 varies along the circumference during discharge, creating a spatial region with a higher electric field strength near the edges 1030T3 and 1030T4 of the inner electrode 1030.

[0151] However, the two edges 1030T3 and 1030T4 of the inner electrode 1030 are embedded in the cladding tube 1050 and do not protrude into the auxiliary discharge space S2. Therefore, the wear caused by the discharge of the inner electrode 1030 can be suppressed. Furthermore, the position of the inner electrode 1030 relative to the inner tube 1060, i.e., the radial cross-sectional length, can be adjusted during the manufacturing process. Alternatively, the cross-sectional shape of the cladding tube 1050 can be circular, or the cross-sectional shape of the inner tube 1060 can be elliptical.

[0152] The auxiliary discharge space S2 is in a reduced pressure state, below atmospheric pressure, or a rare gas (below atmospheric pressure) is enclosed in the auxiliary discharge space S2 to reduce the voltage during ignition. When a high-frequency, high-voltage voltage is applied between the inner electrode 1030 and the outer electrode 1040, the auxiliary discharge space S2 is in a reduced pressure state. Consequently, discharge occurs first in the auxiliary discharge space S2 due to a lower ignition voltage than in the main discharge space S1. Furthermore, a portion of the light (in this case, ultraviolet light) emitted radially from the auxiliary discharge space S2 passes through the inner tube 1060 and reaches the main discharge space S1.

[0153] In addition, a portion of the light radiated from the auxiliary discharge space S2 toward the lamp axis is transmitted toward the end portions 1050T1, 1050T2, 1060T1, and 1060T2 due to the optical fiber effect (an effect based on the same principle as that of optical fibers used for communication circuits) caused by repeated reflections inside the tube walls of the cladding tube 1050 and the inner tube 1060 (the boundary surface of the tube walls).

[0154] Here, a portion of the end 1050T1 of the covering tube 1050 (the end 1060T1 of the inner tube 1060) enters and contacts the small-diameter portion 1022, and an expanded-diameter portion 1061 is provided on the end 1060T2 of the inner tube 1060 (the end 1050T2 of the covering tube 1050). Therefore, ultraviolet light introduced by the fiber optic effect passes through the end 1060T1 of the inner tube 1060 (the end 1050T1 of the covering tube 1050) and the expanded-diameter portion 1061, and irradiates the main discharge space S1 from the ends 1020T1 and 1020T2 of the outer tube 1020. This generates a discharge in the main discharge space S1.

[0155] Thus, the auxiliary discharge space S2 locally formed within the inner tube 1060 improves lighting startup performance. Furthermore, the auxiliary discharge space S2 only needs to be formed in a small spatial region sufficient to generate a minute discharge sufficient for radiated light to reach the main discharge space. Therefore, it does not occupy the majority of the space within the inner tube 1060 but is instead formed as a localized discharge space. Consequently, during lamp lighting, the voltage applied between the inner electrode 1030 and the outer electrode 1040 can be suppressed, reducing the required power and thereby improving lamp durability and life.

[0156] The illuminance distribution (light distribution) along the outer circumference of the discharge vessel varies depending on the shape of the discharge vessel and the location of the discharge generated within it. Furthermore, the discharge state is affected by the electric field intensity distribution determined by the positional relationship of the electrodes (anode and cathode) and the shapes of the cladding tube, inner tube, and auxiliary discharge space. However, because the excimer lamp 1000 does not require changes to the external shape and discharge state of existing double-tube excimer lamps, it can improve ignition start-up performance in ultraviolet irradiation devices and ozone generators without affecting lamp characteristics such as the discharge maintenance voltage and illuminance distribution, or the characteristics of the appropriate power supply.

[0157] Ignition start-up performance can be measured by measuring the reliability (probability [%) of achieving a stable ignition state with the desired emission spectrum from the discharge within the discharge vessel when voltage is applied to the excimer lamp. Excimer lamps require reliable ignition start-up performance (100% reliability) even in low-temperature conditions, darkness, and after prolonged periods of inactivity. However, this embodiment reliably achieves a stable ignition state without requiring a large ignition power supply or auxiliary starting light source. This provides virtually 100% ignition start-up reliability.

[0158] With this configuration, ultraviolet light can be radiated throughout the discharge space S1, achieving a stable main discharge in the discharge space S1. Meanwhile, the auxiliary discharge space S2 is configured to extend over a portion of the axial arrangement range of the inner electrode 1030 so that the electric field intensity is substantially uniform along the lamp axis C. Consequently, the ultraviolet light radiated from the discharge vessel 1000T to the outside of the lamp can have a uniform illumination distribution along the lamp axis C.

[0159] Furthermore, the change in the spatial area of ​​the auxiliary discharge space S2 is gradual, meaning that the inner surface shape of the inner tube 1060 changes smoothly. This improves the stability of the lamp intensity, etc., due to stress concentration on the curved surface (e.g., the two end portions ST1 and ST2 of the inner tube 1060 exposed to the inner surface of the auxiliary discharge space S2). Therefore, even if the inner tube 1060 deteriorates (becomes embrittled) due to high-energy ultraviolet rays generated by the main discharge passing through the discharge space S1, damage to the discharge vessel 1000T starting from the portion covering the auxiliary discharge space S2 can be suppressed.

[0160] The excimer lamp 10 according to the fifth embodiment can be manufactured, for example, as follows.

[0161] First, a glass tube with a cylindrical cross-section (inner tube) is formed to serve as the covering material 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 other methods, and the inner electrode is inserted into the bottomed cylindrical inner tube. After the inner electrode is inserted, the tube is decompressed (vacuumed) and sealed.

[0162] The inner tube is heated while rotating, causing the glass tube to soften and shrink (shrink in diameter). At this point, the inner electrode is in close contact with the glass tube throughout its entire circumferential and axial directions. Furthermore, the diameter is reduced to form an elliptical cross-section. Alternatively, a dielectric coating may be applied to the inner electrode surface, at least within the auxiliary discharge space M, as a covering tube.

[0163] Next, a cladding tube covering the inner electrode is formed from a dielectric material that is transparent to light emitted by the discharge formed in the auxiliary discharge space. Furthermore, a glass tube (inner tube) covering the cladding tube is formed. After the cladding tube and inner tube are formed, the cladding tube is inserted into the inner tube and heated to reduce its diameter.

[0164] At this point, the inner tube is heated to locally fuse along the lamp axis, forming an auxiliary discharge space. Simultaneously with the auxiliary discharge space, a flange-shaped seal (so-called abacus bead shape) is formed on one end of the inner tube. Alternatively, the inner tube can be heated to achieve close contact between the inner circumference and the edge of the foil electrode without rotating the inner tube.

[0165] The outer tube is made by reducing the diameter of one end of a quartz tube that is transparent to the wavelength of ultraviolet light emitted by the discharge in the main discharge space and providing an opening for an inlet tube (exhaust tube). Meanwhile, the outer tube is formed with an opening at the sealed portion with the inner tube. The inner tube is then inserted into the outer tube, coaxially arranged, and heat-fused at the sealed portion to form the discharge tube. Afterwards, the inlet tube is evacuated to remove impurities, discharge gas is introduced into the arc tube, and the inlet tube is hermetically sealed by heat-fusion. Finally, an outer electrode is applied to the outer surface of the outer tube.

[0166] Next, use Figures 11 to 13 A sixth embodiment of an excimer lamp will now be described. In this sixth embodiment, the covering tube and the inner tube are partially welded together so as to circumferentially cover the side surfaces of the foil electrode. This forms an auxiliary discharge space within the area opposing the edge of the foil electrode. The auxiliary discharge space is formed between the covering tube and the inner tube along the lamp axis.

[0167] Figure 11 This is a schematic cross-sectional view of an excimer lamp according to a sixth embodiment as viewed from a side surface along the width direction of a foil-shaped electrode. Figure 12 This is a schematic cross-sectional view of an excimer lamp according to a sixth embodiment as viewed from a side surface along the width direction of a foil-shaped electrode. Figure 13 Equivalent to following Figure 12 BB line cross-sectional view. In addition, Figure 13 The cross-sectional view is equivalent to the cross-sectional view along the Figure 12 A cross-sectional view of the line along the center axis of the lamp.

[0168] like Figure 13 As shown, when the covering tube 1050' is sealed to the foil-like inner electrode 1030, its cross-section in the lamp radial direction is circular. Meanwhile, when the inner tube 1060' is fused to the covering tube 1050', its cross-section in the lamp radial direction is elliptical. In the lamp radial cross-section, the inner surface portion 1060'K2 of the inner tube 1060' along the minor axis (the thickness direction of the inner electrode 30) is fused to the outer surface portion of the covering tube 1050' covering the side surfaces 1030S1 and 1030S2 of the inner electrode 1030.

[0169] As a result, an auxiliary discharge space S2, which is divided into two discharge space regions S2A and S2B, is formed between an inner surface portion 1060'K1 of the inner tube 1060' along the longitudinal direction (the width direction of the inner electrode 1030) and an outer surface portion of the covering tube 1050' covering the edge portions 1030T3 and 1030T4 of the inner electrode 1030.

[0170] In the inner tube 1060', the two discharge space regions S2A and S2B are spatially partitioned by the covering tube 1050'. Furthermore, in the sixth embodiment, unlike the fifth embodiment, the inner tube 1060' has an elliptical cross-section, while the covering tube 1050' has a circular cross-section.

[0171] Discharge space regions S2A and S2B are positioned relative to each other in the width direction of the inner electrode 1030 and are symmetrical about a radial cross-section. The axial section (auxiliary discharge section) M of the auxiliary discharge space S2 is slightly shorter along the lamp axis C than the axial arrangement section L of the outer electrode 1040. Therefore, near the ends 1030T1 and 1030T2 of the inner electrode 1030, the outer circumferential surface of the covering tube 1050' and the inner circumferential surface of the inner tube 1060' are sealed across their entire circumference. Furthermore, within the auxiliary discharge space section M, the outer diameter of the inner tube 1060' is larger than in other sections, and the distance between the outer surface of the inner tube 1060' and the inner surface of the outer tube 1020 is smaller.

[0172] In contrast, between the two end portions 1030T1 and 1030T2 of the inner electrode 1030, in the middle portion of the inner electrode 1030, which includes the axial center of the lamp, only the outer surface portion of the inner tube 1060' corresponding to the portion covering the two side surfaces 1030S1 and 1030S2 of the inner electrode 1030 is partially welded to the covering tube 1050' along the circumferential direction. This forms an auxiliary discharge space S2 (S2A, S2B) in the space in the direction toward which the two edge portions 1030T3 and 1030T4 of the inner electrode 1030 face.

[0173] In the discharge space regions SAT1, SAT2, SBT1, and SBT2 at both ends of the auxiliary discharge space S2, similar to the fifth embodiment, the distance between the cladding tube 1050' and the inner tube 1060' gradually decreases, narrowing as the discharge space region approaches the ends 1050T1 and 1050T2 of the cladding tube 1050'. Furthermore, the distance between the inner surface of the inner tube 1060' and the outer surface of the cladding tube 1050' gradually decreases, and the inner tube 1060' and the cladding tube 1050' are sealed. The outer diameter of the inner tube 1060' also gradually decreases, forming a smoothly curved outer surface.

[0174] like Figure 12 As shown, the radial cross-sectional area of ​​the auxiliary discharge space S2 becomes wider as it approaches the center of the lamp (auxiliary discharge space range M), and narrows as it approaches the discharge space regions SAT1, SAT2, SBT1, and SBT2 at the ends of the auxiliary discharge space S2. Therefore, the distance L1 between the outer circumference of the cladding tube 1050' and the inner circumference of the inner tube 1060' in the center of the auxiliary discharge space S2 along the lamp axis C is longer than the distance L2 between the discharge space regions SAT1 (SBT1) and SAT2 (SBT2) at the ends of the auxiliary discharge space S2.

[0175] Therefore, in the radial cross-sectional shape of the lamp in the discharge space areas S2A and S2B, the length of the distance between the inner surface of the inner tube 1060' and the outer surface of the covering tube 1050' along the radial direction of the lamp is compared with the length T2 of the distance along the width direction of the inner electrode 1030 (edges 1030T3, 1030T4), and the length T1 of the distance along the thickness direction of the inner electrode 1030 (side surfaces 1030S1, 1030S2) is shorter, and becomes tapered along the circumference of the lamp.

[0176] Because the auxiliary discharge space S2 (discharge space regions S2A and S2B) tapers in both the radial and circumferential directions of the lamp, when a high-frequency, high-voltage voltage is applied between the inner electrode 1030 and the outer electrode 1040, a spatial region with a high electric field intensity is formed in the decompressed auxiliary discharge space S2, along the width of the inner electrode 1030 (near the two edges 1030T3 and 1030T4). As a result, discharge first occurs in the auxiliary discharge space S2 at a lower lighting starting voltage than in the main discharge space S1, and then discharge occurs in the spatial region with a higher electric field intensity in the main discharge space S1, facilitating the transition to stable (rated) lighting.

[0177] Furthermore, the electric field intensity in the main discharge space S1 varies along the lamp circumference but is approximately constant along the lamp axial direction. As a result, localized discharges are easily generated in the main discharge space S1, and ultraviolet radiation is emitted with a uniform intensity (illuminance distribution) that varies along the lamp circumference but is uniform along the lamp axial direction C. This enables ultraviolet radiation and ozone generation consistent with the operating environments of the ultraviolet irradiation device and ozone generator.

[0178] The auxiliary discharge space S2 is formed by welding the covering tube 1050 and the inner tube 1060 together over a portion of the circumference. This allows the spatial area of ​​the auxiliary discharge space S2 to change gradually, meaning that the inner surface shape of the covering tube 1050 changes smoothly. This improves the stability of lamp intensity and other factors due to stress concentration on the curved surface. Therefore, even if the covering tube 1050' and the inner tube 1060' deteriorate (become embrittled) due to high-energy ultraviolet rays generated by the main discharge passing through the discharge space S1, damage to the discharge vessel 1000T, originating from the portion covering the auxiliary discharge space S2, can be suppressed.

[0179] The excimer lamp of the sixth embodiment can be manufactured as described below. First, as in the fifth embodiment, the inner electrode is inserted into the glass tube serving as the cladding tube, and the glass tube is heated to reduce its diameter. At this time, the inner electrode is in close contact with the glass tube over the entire circumferential and axial directions. In addition, the diameter is reduced so that the cross section becomes circular. Alternatively, a dielectric may be coated on the surface of the inner electrode. Then, the cladding tube covering the inner electrode is inserted into the inner tube serving as the glass tube, and the cladding tube is heated to reduce its diameter. At this time, heating and reducing the diameter are performed so that a portion of the circumferential direction of the inner tube is fused relative to the cladding tube along the lamp axis C, thereby forming two discharge space regions S1 and S2. The structure other than this is the same as the process of the first embodiment.

[0180] Next, use Figures 14 to 16 A seventh embodiment of an excimer lamp will now be described. In this seventh 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. This forms an auxiliary discharge space within the area facing the side surfaces of the foil electrode. The auxiliary discharge space is formed between the covering tube and the inner tube along the lamp axial direction.

[0181] Figure 14 This is a schematic cross-sectional view of the excimer lamp according to the seventh embodiment as viewed from a side surface along the width direction of the foil-shaped electrode. Figure 15 This is a schematic cross-sectional view of the excimer lamp according to the seventh embodiment as viewed from the side surface along the thickness direction of the foil-shaped electrode. Figure 16 This is a schematic cross-sectional view of the excimer lamp according to the seventh embodiment as viewed from the axial side.

[0182] like Figure 16As shown, in the excimer lamp 1000 as the seventh embodiment, the lamp radial cross-section of the covering tube 1050" is formed into an elliptical shape. On the other hand, the lamp radial cross-section of the inner tube 1060" is formed into a circular shape. Moreover, in the lamp radial cross-section, the inner surface portion of the inner tube 1060" covering the edge 1030T3, 1030T4 side of the inner electrode 1030 is welded to the outer surface portion 1050"K1 of the covering tube 1050" along the long axis direction (the width direction of the inner electrode 1030).

[0183] Furthermore, two spatially separated space regions are formed between the inner surface portion of the inner tube 1060" covering the side surface of the inner electrode 1030 and the outer surface portion 1050" K1 of the covering tube 1050" along the minor axis direction (the thickness direction of the inner electrode). The auxiliary discharge space S2 is composed of these two auxiliary discharge spaces S2A and S2B.

[0184] As in the sixth embodiment, the two discharge space regions S2A and S2B are spatially separated by the covering tube 1050", but in the seventh embodiment, the cross-sectional shape of the inner tube 1060" is circular, while the cross-sectional shape of the covering tube 1050" is elliptical. The discharge space regions S2A and S2B are positioned opposite each other in the thickness direction of the inner electrode 1030 and are symmetrical about the radial cross section.

[0185] In the radial cross-sectional shape of the discharge space regions S2A and S2B, the length of the spacing between the inner surface of the inner tube 1060" and the outer surface of the covering tube 1050" along the radial direction of the lamp is longer than the length T2 of the spacing along the width direction of the inner electrode 1030 (edges 1030T3, 1030T4), and the length T1 of the spacing on the side of the thickness direction of the inner electrode 1030 (side surfaces 1030S1, 1030S2) is longer, and the discharge space regions S2A and S2B become tapered along the circumference of the lamp.

[0186] With this structure, when a high-frequency, high-voltage voltage is applied between the inner electrode 1030 and the outer electrode 1040, a discharge first occurs in the auxiliary discharge space S2, which is in a decompressed state, due to a lower lighting starting voltage than the main discharge space S1. Consequently, a discharge can occur in a region within the main discharge space S1 where the electric field intensity is higher, leading to a transition to stable (rated) lighting.

[0187] Thus, according to the seventh embodiment, by adjusting the shapes of the covering tube and the inner tube and the welded portion along the circumferential direction, the two discharge space regions S2A and S2B can be formed at desired positions within the inner tube 1060″ regardless of the cross-sectional length direction (extension direction) of the foil-shaped inner electrode 30.

[0188] The excimer lamp 1000 can be manufactured through the same manufacturing process as that of the sixth embodiment.

[0189] The axial section M of the auxiliary discharge space S2 is configured to coincide with the axial arrangement section L of the outer electrode 1040 . However, the auxiliary discharge space S2 may be formed in the center or end of the lamp, or locally between the inner tube 1060 and the covering tube 1050 along the lamp axis C.

[0190] 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 may be disposed on the outer surface of the discharge tube. Furthermore, the light emitted from the auxiliary discharge space is not limited to ultraviolet light but may also be visible light.

[0191] Next, use Figure 17 、 Figure 18 An excimer lamp according to an eighth embodiment will be described.

[0192] Figure 17 This is a schematic cross-sectional view of an excimer lamp according to the eighth embodiment as viewed from the side. Figure 18 This is a schematic cross-sectional view of an excimer lamp according to an eighth embodiment as viewed from the axial side. Figure 18 Equivalent to following Figure 17 BB line cross-sectional view. In addition, Figure 17 The cross-sectional view is equivalent to the cross-sectional view along the Figure 18 A cross-sectional view of the line along the center axis of the lamp.

[0193] Excimer lamp 2000 includes a discharge vessel 2000T, which is formed from an outer tube 2020 and an inner tube 2050, each made of a dielectric material such as quartz glass, each having a substantially cylindrical cross-section. A strip-shaped foil electrode (hereinafter referred to as the inner electrode) 2030, extending in a width along the tube diameter (hereinafter also referred to as the lamp radial direction), is covered by a columnar dielectric (hereinafter referred to as the inner tube) 2050, extending along the tube axis (hereinafter also referred to as the lamp axis) C. The inner electrode 2030 does not protrude into the annular discharge space (hereinafter referred to as the main discharge space) S1 formed between the outer tube 2020 and the inner tube 2050. The inner tube 2050 has a substantially circular cross-section.

[0194] The excimer lamp 2000 includes a portion (hereinafter referred to as an extension) 2052 that extends beyond the end 2020T2 of the discharge vessel 2000T (outer tube 2020) along the lamp axis C and is not covered by the outer tube 2020. A power supply line 2070 extends through the interior of this end 2050T2. However, the extension 2052 may be formed by welding a component separate from the inner tube 2050. The small-diameter portion 2022, formed during lamp manufacturing, protrudes from the discharge vessel 2000T (outer tube 2020) toward the front end of the lamp along the lamp axis C.

[0195] The diameter of the small-diameter portion 2022 is smaller than the diameter of the discharge vessel 2000T, that is, the diameter of a portion of the lamp's axial range where the outer electrode 2040 is disposed (herein referred to as the axial arrangement range). Here, the front end of the outer tube 2020 is heated and deformed to reduce its diameter, and the exhaust pipe, which has a smaller diameter than the outer tube 2020, is welded. Thus, the small-diameter portion 2022 is integrally formed with the discharge vessel 2000T. Alternatively, the exhaust pipe used for lamp manufacturing may be located at a different location from the small-diameter portion.

[0196] In this embodiment, the end portion 2050T1 of the inner tube 2050 enters the small-diameter portion 2022 and contacts the small-diameter portion 2022. Therefore, the inner tube 2050 is stably held coaxially within the outer tube 2020. Furthermore, the outer surface of the end portion 2050T1 of the inner tube 2050 has a tapered convex curved surface, while the inner surface of the small-diameter portion 2022 has a tapered concave curved surface.

[0197] This allows for stable coaxial retention without damage even with respect to dimensional errors caused by thermoforming. This interlocking state allows the front end portion 2030T1 of the inner electrode 2030, along the lamp axis C, to be positioned closer to the rear end (center of the discharge vessel) than the small-diameter portion 2022, without entering the interior space of the small-diameter portion 2022.

[0198] An electrode (hereinafter referred to as the outer electrode) 2040 is disposed on the outer surface 2020S of the outer tube 2020. The outer electrode 2040 is a structure in which a linear electrode portion made of a conductive metal is wound along the surface of the outer tube 2020, and is spirally wound at predetermined intervals along the tube axis C.

[0199] The axial arrangement range L of the outer electrode 2040 is set to the range of the constant inner diameter portion 2020T0 (hereinafter referred to as the cylindrical portion) between the tapered ends 2020T1 and 2020T2 of the outer tube 2020. The axial length of the inner electrode 30 corresponds to the axial arrangement range L of the outer electrode 2040. A power supply line 2070 connected to the end of the inner electrode 2030 is connected to an external power supply unit (not shown), and power is supplied to the excimer lamp 2000 via the power supply line 2070.

[0200] By applying a high frequency (e.g., several kHz to tens of MHz) and a high voltage (e.g., several kV to more than ten kV) to the inner and outer electrodes, excimer light is emitted from the discharge space S1. Here, ultraviolet light (e.g., with a wavelength of 172 nm) is emitted outside the discharge vessel. Therefore, the excimer lamp 2000 can be used in ozone generators that perform sterilization and deodorization based on ozone generation, as well as in ultraviolet irradiation devices that directly irradiate objects with ultraviolet light.

[0201] A discharge space S2 for assisting lighting startup (hereinafter referred to as an auxiliary discharge space) is formed in the extension portion 2052. Figure 17 As shown, a portion of the extension 2052 of the inner tube 2050 along the lamp axis C is not locally welded (sealed) over the entire circumference of the inner electrode 2030. On the other hand, the inner tube 2050 is sealed over the entire circumference at both axial end portions 2030T1 and 2030T2 of the inner electrode 2030. This forms an auxiliary discharge space S2.

[0202] Here, the range M of the auxiliary discharge space S2 along the lamp axis C (auxiliary discharge space range) is defined as the section outside the axial arrangement range of the inner electrode 2030, which corresponds to the axial arrangement range L of the outer electrode 2040. Specifically, within the axial arrangement range L of the outer electrode 2040, the inner electrode 2030 is completely circumferentially sealed by the inner tube 2050 at both ends 2030T1 and 2030T2 of the inner electrode 2030. In contrast, the entire outer circumference of the inner electrode 2030 is exposed in the middle portion of the extended portion 2052 of the inner tube 2050, forming the auxiliary discharge space S2 surrounding the entire outer circumference of the inner electrode 2030. Furthermore, within the auxiliary discharge space range M, the outer diameter of the inner tube 2050 is larger than that of the rest of the range.

[0203] Furthermore, at the two ends ST1 and ST2 of the inner electrode 2030 exposed within the auxiliary discharge space S2 (the two ends of the auxiliary discharge space range M), the distance between the inner electrode 2030 and the inner tube 2050 gradually decreases, and the discharge space narrows as the area of ​​the space approaches the two ends 2050T1 and 2050T2 of the inner tube 2050. Furthermore, the distance between the inner surface of the inner tube 2050 and the outer surface of the inner electrode 2030 gradually decreases, and the inner electrode 2030 and the inner tube 2050 are sealed. The outer diameter of the inner tube 2050 also gradually decreases, forming a smooth curved surface.

[0204] The auxiliary discharge space S2 has a wider radial cross-sectional area closer to the center of the lamp (auxiliary discharge space range M) and a narrower area closer to the small-diameter portion 2022 and the extended portion 2052 at either end of the discharge vessel 2000T. Therefore, the distance L1 between the outer circumferential surface of the inner electrode 2030 and the inner circumferential surface of the inner tube 2050 in the center portion of the auxiliary discharge space S2 along the lamp axis C is longer than the distance L2 between the two ends ST1 and ST2 of the inner tube 2050 exposed in the inner surface of the auxiliary discharge space S2.

[0205] In addition, the two edges 2030T3 and 2030T4 of the foil-shaped inner electrode 2030 are blade-shaped. The inner electrode 2030 is sharpened from the center in the width direction toward the edge (end), and its thickness becomes thinner than the thickness of the center in the width direction. The two edges 2030T3 and 2030T4 are sharp.

[0206] Therefore, the closer the auxiliary discharge space S2 is to the center of the inner electrode 2030 in the width direction (lamp radial direction), the wider the radial cross-sectional area (refer to Figure 18 Therefore, the length of the distance between the outer surface of the inner electrode 2030 and the inner surface of the inner tube 2050 along the radial direction of the lamp is equal to the length T2 of the distance along the width direction near the two edges 2030T3 and 2030T4 of the inner electrode 2030 (equivalent to Figure 17 Compared with L1), the length T1 of the spacing distance along the thickness direction near the center (lamp center axis) is longer and becomes narrower toward the two edge portions 2030T3 and 2030T4 of the inner electrode 2030.

[0207] That is, the auxiliary discharge space S2 (discharge space regions S2A and S2B) narrows toward the ends 2030T1 and 2030T2 in the longitudinal direction (lamp axial direction) and the edges 2030T3 and 2030T4 in the width direction (lamp radial direction) along the surface of the foil-shaped inner electrode 2030 .

[0208] The auxiliary discharge space S2 is in a reduced pressure state, below atmospheric pressure, or a rare gas (below atmospheric pressure) is enclosed in the auxiliary discharge space S2 to reduce the voltage during ignition. When a high-frequency, high-voltage voltage is applied between the inner electrode 2030 and the outer electrode 2040, the auxiliary discharge space S2 is in a reduced pressure state. Consequently, discharge occurs first in the auxiliary discharge space S2 due to a lower ignition voltage than in the main discharge space S1. Furthermore, a portion of the light (in this case, ultraviolet light) radiated from the auxiliary discharge space S2 toward the lamp axis passes through the inner tube 2050 and reaches the main discharge space S1.

[0209] Furthermore, the inner electrode 2030's ends 2030T1 and 2030T2 are largely buried in contact with each other within the inner tube 2050, while the inner electrode 2030's edges 2030T3 and 2030T4 are partially exposed in the auxiliary discharge space S2. This creates a spatial region with a high electric field intensity within the decompressed auxiliary discharge space S2. This ensures reliable discharge in the auxiliary discharge space S2 at a lower ignition starting voltage than the main discharge space S1. Furthermore, the power required for lamp lighting can be reduced, thereby suppressing power consumption caused by discharge from the inner electrode 2030 (particularly at the edges).

[0210] A portion of the light radiated toward the lamp axis from the discharge generated in the auxiliary discharge space S2 is transmitted toward the end portion 2050T1 of the inner tube 2050 by a so-called fiber optic effect, which repeatedly reflects within the tube wall (the boundary surface of the tube wall) of the inner tube 2050. A portion of the ultraviolet light transmitted by the fiber optic effect passes through the expanded diameter portion 2051 of the inner tube 2050 and irradiates the main discharge space S1 from the end portion 2020T2 of the outer tube 2020.

[0211] Furthermore, because the end 2050T1 of the inner tube 2050 partially enters and contacts the small-diameter portion 2022, a portion of the light radiated axially from the lamp passes through the end 2050T1 of the inner tube 2050 and irradiates the main discharge space S1 from the end 2020T1 side of the outer tube 2020. This ultraviolet light, transmitted by the fiber optic effect, irradiates the main discharge space S1, generating a discharge within the main discharge space S1. Thus, by forming the auxiliary discharge space S2 in a portion of the extended portion 2052 of the inner tube 2050, ignition and starting performance are improved.

[0212] Here, the auxiliary discharge space S2 is formed as a small discharge space region just enough for the radiated light to reach the main discharge space S1, and is not formed as a discharge space region that occupies most of the extended portion 2052 of the inner tube 2050. However, since the auxiliary discharge space S2 is formed at adjacent positions along the lamp axis outside the discharge vessel 2000T, the voltage applied between the inner electrode 2030 and the outer electrode 2040 can be suppressed during lamp lighting (during the main discharge). By reducing the required power, lamp durability and lamp life can be improved.

[0213] Furthermore, since the auxiliary discharge space S2 is formed coaxially with the inner tube 2050, light is irradiated from the auxiliary discharge space S2 toward the main discharge space S1 from both sides of the ends 2050T1 and 2050T2 of the inner tube 2050. This allows a stable main discharge to be generated in the main discharge space S1.

[0214] The illuminance distribution (light distribution) along the outer circumference of the discharge vessel varies depending on the shape of the discharge vessel and the location of the discharge generated therein. Furthermore, the discharge state is affected by the electric field intensity distribution determined by the positional relationship of the electrodes (anode and cathode) and the shapes of the inner tube and auxiliary discharge space. However, the excimer lamp 2000 does not change the shape or discharge state of existing double-tube excimer lamps. Therefore, in ultraviolet irradiation devices and ozone generators, it is possible to improve lighting startup performance without affecting lamp characteristics such as the discharge maintenance voltage and illuminance distribution, or the characteristics of the power supply suitable for these lamps.

[0215] Ignition start-up performance can be measured by measuring the reliability (probability [%) of achieving a stable ignition state, where the desired emission spectrum is obtained from the discharge within the discharge vessel, when voltage is applied to the excimer lamp. Excimer lamps require reliable ignition start-up performance (100% reliability) even in low-temperature conditions, darkness, and after prolonged periods of inactivity. However, this embodiment reliably achieves a stable ignition state without requiring a large ignition power supply or auxiliary starting light source, effectively achieving 100% ignition start-up reliability.

[0216] The spatial area forming the auxiliary discharge space S2 in the extension portion 2052 and the interval M formed along the lamp axis C can be adjusted as appropriate. For example, by fusing only the two edges 2020T3 and 2030T4 of the inner electrode 30 to the inner tube 2050 so that they are not exposed, two discharge space regions S2A and S2B spatially separated by the foil-shaped inner electrode 2030 can be formed as the auxiliary discharge space S2. Alternatively, a configuration can be employed in which the two edges 2020T3 and 2020T4 of the inner electrode 2030 are not exposed in the auxiliary discharge space S2 by coating (covering) the surface of the inner electrode with a dielectric relative to the set auxiliary discharge space range M.

[0217] Such an excimer lamp 2000 can be manufactured by the following manufacturing method, for example.

[0218] A glass tube (inner tube) with a cylindrical cross section, serving as a covering for a foil-shaped electrode (inner electrode), is formed from a dielectric material that is transparent to light emitted by the discharge formed in the auxiliary discharge space. After the inner tube is formed, a power supply line is connected to the foil-shaped electrode by resistance welding or other means, and the foil-shaped electrode is inserted into the bottomed cylindrical glass tube.

[0219] After inserting a foil electrode serving as the inner electrode into a glass tube serving as the inner tube, the interior of the glass tube is brought to a reduced pressure state (vacuum) and sealed. At this time, a rare gas below atmospheric pressure may be introduced into the glass tube. The glass tube is then heated while rotating to deform, softening and shrinking (reducing its diameter). The glass tube and the inner electrode are then partially fused together, forming an auxiliary discharge space locally at the end of the glass tube.

[0220] In this case, the inner peripheral surface of the glass tube may be brought into close contact with the edge of the foil electrode along the width direction (tube diameter direction) so that the edge of the foil electrode is not exposed and the space where the glass tube and the foil electrode are not in contact may be formed as the auxiliary discharge space.

[0221] Furthermore, one end of the glass tube, serving as the inner tube, is heated to form a flange-like (so-called abacus bead-like) expanded diameter portion. Alternatively, the glass tube can be heated axially to achieve close contact between the inner circumferential surface and the portion of the glass tube facing the edge of the foil electrode, rather than rotating the tube. By sealing the entire circumference of the foil electrode's end along the longitudinal direction (tube axis), the foil electrode's end is embedded in the glass tube, preventing the foil electrode from protruding into the auxiliary discharge space.

[0222] The outer tube is formed by reducing the diameter of one end of a quartz tube that is transparent to the wavelength of ultraviolet rays emitted by the discharge formed in the main discharge space and providing an opening for an inlet tube (exhaust tube). On the other hand, the outer tube is formed by opening the sealing portion with the expanded diameter portion of the inner tube.

[0223] Next, the inner tube is inserted into the outer tube and coaxially arranged. The discharge tube and the expanded diameter portion of the inner tube are heat-fused to form the discharge vessel. Afterwards, the inlet tube is evacuated to remove impurities, discharge gas is introduced into the discharge vessel, and the inlet tube is hermetically sealed by heat-fusion. Finally, the outer electrode is placed on the outer surface of the outer tube.

[0224] In the present embodiment, the inner electrode 2030 is configured to extend throughout the discharge vessel 2000T and the extension portion 2052 . However, different inner electrodes may be provided in the discharge vessel 2000T and the extension portion 2052 .

[0225] Figure 19 This is a schematic cross-sectional view of an excimer lamp according to a modified example of the eighth embodiment, viewed from the side. Here, two foil-shaped inner electrodes 2030A and 2030B are connected by an internal power supply line 2071. Furthermore, inner electrode 2030B is disposed within an extension 2052 of inner tube 2050, located outside outer tube 2020. Inner electrodes 2030A and 2030B face each other, and their radial cross-sectional positions (extension directions) are aligned.

[0226] As in the eighth embodiment, an auxiliary discharge space S2 is formed in the extension portion 2052 of the inner tube 2050. This allows for lighting and improved performance similar to this embodiment, even when two inner electrodes 2030A and 2030B are provided. Furthermore, the use of an internal power supply line 2071 further reduces power consumption during lamp lighting.

[0227] The outer diameter (wall thickness) of the expanded diameter portion 2051 is larger than the outer diameter (wall thickness) of the other portions of the inner tube 2050, making it difficult to reduce the diameter by heating. Therefore, by providing the internal power supply line 2071 in the expanded diameter portion 2051, both the heat-reduction of the expanded diameter portion 2051 relative to the internal power supply line 2071 and the welding to the end portion 2020T2 of the outer tube 2020 can be achieved, thereby facilitating manufacturing.

[0228] Furthermore, the portion of the inner electrodes 2030A and 2030B where the electric field is concentrated (particularly the two knife-edge-shaped edges 2020T3 and 2030T4) is located away from the expanded diameter portion 2051. Thus, by spacing the inner electrodes 2030A and 2030B away from the expanded diameter portion 2051, abnormal discharge (creeping discharge) near the end portion 2020T2 of the outer tube can be reliably prevented.

[0229] 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 may be disposed on the outer surface of the discharge tube. Furthermore, the light emitted from the auxiliary discharge space is not limited to ultraviolet light but may also be visible light.

Claims

1. An excimer lamp, characterized in that The excimer lamp has: a dielectric covering a foil-shaped electrode arranged along the axial direction of the lamp; and a discharge vessel, which is fused with the dielectric to form a main discharge space, The foil electrode is partially sealed to the dielectric within the lamp axial range of the main discharge space, so as to form an auxiliary discharge space inside the dielectric, the auxiliary discharge space being entirely within the lamp axial range of the main discharge space.

2. The excimer lamp according to claim 1, characterized in that The foil-shaped electrode is fused to the dielectric at at least one end portion in the longitudinal direction of the foil-shaped electrode. The auxiliary discharge space is formed between the surface of the foil electrode and the inner surface of the dielectric so that the electric field intensity varies along at least one of the lamp axial direction and the lamp circumferential direction.

3. The excimer lamp according to claim 2, characterized in that The foil electrode is sealed with the dielectric in a region with low electric field intensity along at least one of the lamp axial direction and the lamp circumferential direction of the foil electrode, and forms the auxiliary discharge space in a region with high electric field intensity.

4. The excimer lamp according to claim 2, characterized in that The foil electrode is sealed with the dielectric in a region with a higher electric field intensity along at least one of the lamp axial direction and the lamp circumferential direction of the foil electrode, and forms the auxiliary discharge space in a region with a lower electric field intensity.

5. The excimer lamp according to claim 3, characterized in that An edge portion of the foil-shaped electrode is separated from an inner surface of the dielectric in the auxiliary discharge space.

6. The excimer lamp according to claim 4, characterized in that The edge of the foil-shaped electrode is fused to the dielectric in the auxiliary discharge space.

7. The excimer lamp according to any one of claims 1 to 6, characterized in that The front end of the front end portion of the dielectric body enters the small diameter portion provided at the front end of the discharge container. The front end of the foil-shaped electrode along the lamp axis is located on the rear end side of the small diameter portion.

8. The excimer lamp according to any one of claims 1 to 6, characterized in that The auxiliary discharge space is formed such that a distance between the dielectric and the foil electrode along the width direction of the foil electrode at an edge portion is shorter than a distance between the dielectric and the foil electrode along the width direction of the foil electrode at a center portion.

9. The excimer lamp according to any one of claims 1 to 6, characterized in that The auxiliary discharge space is formed such that a distance between the dielectric and the foil electrode along the longitudinal direction of the foil electrode at the end side is shorter than a distance between the dielectric and the foil electrode along the longitudinal direction of the foil electrode at the center.

10. A method for lighting an excimer lamp, the excimer lamp comprising: an inner tube covering an inner electrode arranged along the axial direction of the lamp; and an outer tube welded to the enlarged diameter portion of the inner tube to form a main discharge space between the outer tube and the inner tube; It is characterized by: An auxiliary discharge space is formed between the surface of the inner electrode and the inner surface of the inner tube by partially sealing the inner electrode and the inner tube, and the auxiliary discharge space is entirely within the axial range of the lamp of the main discharge space. A portion of the light radiated from the auxiliary discharge space toward the lamp axial direction passes through the front end portion of the inner tube on the main discharge space side and the expanded diameter portion and is irradiated into the main discharge space.

11. A method for manufacturing an excimer lamp, characterized in that: The manufacturing method of the excimer lamp includes the following steps: Inserting a foil-shaped inner electrode into a glass tube serving as an inner tube; The inner tube is sealed by bringing the inner tube into a reduced pressure state, or a rare gas is sealed into the inner tube at a pressure lower than atmospheric pressure; and The inner tube is heated and reduced in diameter, and the inner tube is partially sealed to the inner electrode, so that an auxiliary discharge space is formed in at least a portion of the inner tube along the tube axis, which is entirely within the tube axis range of the main discharge space.

12. The method for manufacturing an excimer lamp according to claim 11, wherein: The main discharge space is formed by integrally heating and welding the outer tube and the enlarged diameter portion of the inner tube.

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