Excimer lamp

Abstract

To provide a hollow-type excimer lamp which enables higher illuminance.SOLUTION: An excimer lamp 10, which is a hollow-type excimer lamp for emitting ultraviolet light, comprises a discharge tube 20 obtained by welding an inner tube 25 to an outer tube 22. The excimer lamp 10 further comprises a foil-like inner electrode 30 and an outer electrode 40. A cladding tube 60 is welded such that it covers around the outer tube 22 and the inner electrode 30. The foil-like inner electrode 30 is embedded between the cladding tube 60 and the outer tube 22. The inner electrode 30 has a flat part 32 and is sharpened toward a tip end.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an excimer lamp, and more particularly to a hollow excimer lamp that includes a discharge tube (discharge vessel) with a double tube structure and irradiates an object to be irradiated inside the inner tube with ultraviolet rays. [Background technology]

[0002] In hollow excimer lamps, the inner tube is welded to the outer tube and arranged coaxially. In order to irradiate ultraviolet rays onto an object to be irradiated, such as a source gas flowing inside the inner tube, a foil-shaped inner electrode is embedded in the outer tube and an outer electrode is arranged on the surface of the outer tube so as to face the inner electrode (see Patent Document 1).

[0003] Furthermore, by embedding an inner electrode between the discharge vessel and a covering tube that covers the discharge vessel and configuring an outer electrode such as an aluminum film to cover the covering tube, it is possible to irradiate ultraviolet rays onto an object to be irradiated inside the inner tube (see Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-146295 A [Patent Document 2] JP 2020-107424 A Summary of the Invention [Problem to be solved by the invention]

[0005] When applying a high voltage to increase the illuminance of an excimer lamp, it is necessary to configure the inner electrode accordingly (for example, by expanding the width of the foil-shaped electrode). However, in excimer lamps (especially small excimer lamps), it is necessary to increase the volume of the discharge space to increase the efficiency of ultraviolet irradiation, and there are limitations on the diameter and thickness of the inner and outer tubes that make up the discharge tube of the double-tube structure. As a result, there is a risk that the embedded inner electrode will peel off.

[0006] Therefore, there is a need to provide a hollow excimer lamp that can achieve high illuminance. [Means for solving the problem]

[0007] The excimer lamp of the present invention is a hollow excimer lamp that includes an outer tube having an outer electrode disposed on its outer surface, an inner tube arranged coaxially within the outer tube, and a foil-shaped inner electrode embedded between the outer tube and a covering tube that covers at least a portion of the outer tube. The inner electrode has a flat portion with a substantially constant thickness along the electrode width direction and is sharpened from the flat portion toward both ends.

[0008] The inner tube can have a variety of configurations. For example, the inner tube can be configured to have an inner tube large diameter portion provided with a flange-shaped portion that is welded to the outer tube, and an inner tube small diameter portion that is formed on the discharge space side of the inner tube large diameter portion and has a smaller diameter than the inner tube large diameter portion.

[0009] The configuration of the inner pipe may be varied, for example, the outer pipe may have an outer pipe small diameter portion that is not covered by the cladding pipe and has a smaller diameter than the portion covered by the cladding pipe, and that faces at least a portion of the inner pipe small diameter portion.

[0010] For example, the thickness of the inner tube can be set to be smaller than the thicknesses of the outer tube and the covering tube. Also, the electrode width of the inner electrode can be set to be smaller than the outer diameter of the inner tube. The inner diameter of the outer tube can be set to be 1.3 times or more the outer diameter of the inner tube.

[0011] For example, an ultraviolet reflective film is formed on the inner surface of the outer tube in accordance with the section facing the inner electrode.

[0012] The discharge space may be configured in various ways, and in addition to the annular discharge space formed around the inner tube, an auxiliary discharge space may be formed, for example, the covering tube may be partially fused to the outer tube, and the auxiliary discharge space may be formed in the unfused portion between the covering tube and the outer tube. A part of the inner electrode may be exposed to the auxiliary discharge space. Effect of the Invention

[0013] According to the present invention, it is possible to provide a hollow excimer lamp that can achieve high illuminance. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic cross-sectional view of an excimer lamp according to a first embodiment. [Diagram 2] FIG. 2 is a schematic cross-sectional view taken along line II-II of FIG. [Diagram 3] 2 is a partially enlarged cross-sectional view of the discharge tube 20 in the vicinity of where the foil electrodes are arranged. [Figure 4] FIG. 4 is a schematic cross-sectional view of an excimer lamp according to a second embodiment. [Diagram 5] FIG. 5 is a schematic cross-sectional view taken along line VV of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, the excimer lamp according to the present embodiment will be described with reference to the drawings.

[0016] Fig. 1 is a schematic cross-sectional view of an excimer lamp according to a first embodiment of the present invention, and Fig. 2 is a schematic cross-sectional view taken along line II-II in Fig. 1.

[0017] The excimer lamp 10 is configured as a hollow excimer lamp that irradiates an object to be irradiated with ultraviolet light by passing the object through a flow path R formed along the lamp axis C. Here, the lamp is configured so that a fluid such as a raw material gas containing oxygen flows through the flow path R.

[0018] The excimer lamp 10 includes a discharge tube (discharge vessel) 20 made of quartz glass or the like. The discharge tube 20 has a double-tube structure in which an outer tube 22 is welded to brim-shaped portions M1, M2 provided on an inner tube 25, and the inner tube 25 is disposed coaxially with the outer tube 22. A discharge space S formed within the discharge tube 20 is filled with a discharge gas, such as a rare gas such as xenon, or a mixture of a rare gas and a halogen gas.

[0019] The covering tube 60 is a tubular member made of quartz glass or the like that is coaxially welded to the outer tube 22, and covers a portion of the discharge tube 20 along the lamp axis C over the entire circumferential direction.

[0020] A foil-shaped electrode (hereinafter referred to as a foil electrode or an inner electrode, as necessary) 30 is provided between the covering tube 60 and the discharge tube 20. Specifically, the outer surface of the outer tube 22 and the inner surface of the covering tube 60 are welded together to be integrated, and the inner electrode 30 is embedded inside the tube wall. One end of the inner electrode 30 is connected to a power supply rod 70 that is connected to a power source unit (not shown).

[0021] The outer electrode 40 is provided so as to cover the entire outer surface of the covering tube 60 in the circumferential direction. The outer electrode 40 is configured as a film electrode such as an aluminum film here. The outer electrode 40 is connected to the earth side via a power supply line or the like connected to a cylindrical power supply member (not shown) wound around the circumference.

[0022] The outer electrode 40 is provided so as to be separated from the end 60T2 of the covering tube 60 from which the power feed rod 70 protrudes, thereby preventing dielectric breakdown between the outer electrode 40 and the power feed rod 70 (inner electrode 30). Furthermore, by covering the end 60T2 side of the covering tube 60 with an insulating covering member (here, the insulating tube 50), the effect of preventing dielectric breakdown can be enhanced.

[0023] In the inner tube 25, portions 27A, 27B having a relatively large outer diameter (hereinafter referred to as the inner tube large diameter portion) are formed near the welded portions M1, M2 with the outer tube 22. In the discharge space S portion between the inner tube large diameter portions 27A, 27B, a portion 26 having a relatively small outer diameter (hereinafter referred to as the inner tube small diameter portion) is formed. The joint portion between the inner tube large diameter portions 27A, 27B and the inner tube small diameter portion 26 has a shape in which the outer diameter continuously changes along the axial direction.

[0024] The inner diameter D0 of the inner pipe 25 is approximately constant throughout the inner pipe large diameter portions 27A, 27B and the inner pipe small diameter portion 26. On the other hand, the thickness T11 of the inner pipe large diameter portions 27A, 27B is greater than the thickness T10 of the inner pipe small diameter portion 26, and the respective outer diameters D10, D11 are different (D11>D10).

[0025] The outer tube 22 has a relatively large diameter portion (hereinafter referred to as the outer tube large diameter portion) 24 formed to match the electrode opposing section K along the lamp axis C where the outer electrode 40 and the inner electrode 30 oppose each other along the lamp radial direction, i.e., the portion where the covering tube 60 is provided.

[0026] In addition, the outer tube large diameter portion 24 is formed with a flange-shaped portion (outer tube flange portion) M3, which is a portion having a relatively large thickness and outer diameter compared to other portions, near one end 60T1 of the covering tube 60, and a portion having a relatively small diameter (hereinafter referred to as the outer tube small diameter portion) 23 is formed on the discharge tube 20 end side toward the welded portion M1 from the outer tube flange portion M3. The outer tube large diameter portion 24 and the outer tube small diameter portion 23 are continuously and smoothly connected. The introduction tube 21 provided in the outer tube small diameter portion 23 is configured to face a part of the inner tube small diameter portion 26 without facing the inner tube large diameter portion 27A.

[0027] The spatial region of the discharge space S formed within the discharge tube 20, in particular the spatial region of the discharge space S in the range of the electrode opposing section K where the outer electrode 40 and the inner electrode 30 where the discharge occurs are opposed along the lamp radial direction, will depend on the ultraviolet illuminance and irradiation amount (light amount) required for the fluid passing through the flow path R in the inner tube 25, and the size and axial length of the inner diameter D20 of the outer tube 22 (outer tube large diameter section 24) and the outer diameter D10 of the inner tube (inner tube small diameter section 26) are determined accordingly.

[0028] Here, the inner diameter D20 of the outer pipe 22 is set to be 1.3 times or more the outer diameter D10 of the opposing inner pipe small diameter portion 26. Preferably, the inner diameter D20 of the outer pipe 22 is set to be 3 times or more the outer diameter D10 of the inner pipe small diameter portion 26.

[0029] The thickness T10 (of the tube wall) of the inner tube small diameter portion 26 is smaller than the combined thickness T30 of the cladding tube 60 and the thickness T20 of the outer tube 22 (the outer tube large diameter portion 24). However, the thickness of the inner electrode 30 is much smaller than the cladding tube 60 and the outer tube 22, and therefore is considered to be included in the above thicknesses. Also, the thickness T20 of the outer tube 22 is smaller than the thickness T30 of the cladding tube 60. However, the thickness T20 of the outer tube 22 may be larger than the thickness T30 of the cladding tube 60. In either case, the thickness T10 of the inner tube is determined to be smaller than the thickness T30 of the cladding tube 60 and smaller than the thickness T20 of the outer tube 22.

[0030] A reflective film 95 that reflects ultraviolet light is formed on the inner surface of the outer tube 22. Here, the reflective film 95 is formed to match the electrode opposing section K along the lamp axis C, and is formed in a range including the joint portion where the inner diameters of the outer tube large diameter portion 24 and the outer tube small diameter portion 23 are smoothly connected, but is not formed near the brim-shaped portions M1 and M2 and the introduction tube 21. The reflective film 95 is made of, for example, SiO2. Auxiliary lighting light is transmitted through the reflective film 95 and irradiated into the inside of the outer tube 22.

[0031] Next, the shape of the inner electrode 30 (hereinafter, in the description using FIG. 3, referred to as a foil electrode) will be described with reference to FIG.

[0032] 3 is a partially enlarged cross-sectional view of discharge tube 20, enlarging the area around where foil electrode 30 is arranged. Here, the boundary between the discharge vessel and the covering tube and the arc-shaped (curved) bends of the foil electrode are omitted and shown as straight lines (flat surfaces), with the width direction of foil electrode 30 being the X direction and the thickness direction being the Y direction.

[0033] The foil electrode 30 is an electrode formed so that its thickness (electrode thickness) is very thin compared to its width (electrode width) w, and its thickness t is suppressed to 1 / 30 or less of the electrode width w. The foil electrode 30 has a flat portion 32 having a substantially constant thickness t, and has wedge-shaped portions 34A, 34B that taper in a wedge shape from both widthwise ends 32A, 32B of the flat portion 32 to both widthwise ends E1, E2 of the foil electrode 30.

[0034] Here, the wedge-shaped portions 34A, 34B of the foil electrode 30 have a sharply pointed wedge shape up to the edge E. That is, the foil electrode 30 is not sharpened between the center in the width direction and the edge, but is sharpened from both ends 32A, 32B along the width direction of the flat portion 32 to both ends E1, E2 of the entire foil electrode 30 in the width direction.

[0035] Furthermore, both ends E1, E2 in the width direction of the foil electrode 30 are not rounded and thick, but are sharp and have such an edge shape that both ends E1, E2 in the width direction are represented as dots in cross section. The thickness of the foil electrode 30 becomes thinner at constant inclination angles θ1, θ2 (angles θ of the edge E with respect to the X direction, not shown here) from both ends 32A, 32B in the width direction of the flat portion 32 toward both ends E1, E2 in the width direction.

[0036] Here, the angles θ1 and θ2 of both ends E1 and E2 of the foil electrode 30 in the width direction are determined in consideration of the likelihood of peeling due to a gap occurring at the boundary between the embedded covering tube 60 and the outer tube 22, the size of the cross-sectional area of ​​the flat portion according to the current capacity, and the suppression of temperature rise due to Joule heat generation. Here, the angles θ1 and θ2 are both set in the range of 2° to 15°, preferably in the range of 2° to 10°, and are also set to the same angle (hereinafter also referred to as θ).

[0037] Here, angles θ1 and θ2 are defined as angles at which the thickness increases from the edge E of the foil electrode 30 toward both ends 32A, 32B in the width direction of the flat portion 32, when a cross section of the foil electrode 30 is enlarged and observed within a range of approximately 100 μm from the edge E. In the foil electrode 30, an edge-like edge E having such angles θ1 and θ2 is formed over the entire electrode along the tube axis C direction.

[0038] The widthwise center (central portion) of the flat portion 32 is formed along the tube axis C, and the wedge-shaped portions 34A, 34B are symmetrical with respect to the flat portion 32. Moreover, the widthwise length d1 (d1 / w) of the wedge-shaped portions 34A, 34B with respect to the electrode width W of the foil electrode 30 is set to be 0.2 or less.

[0039] Accordingly, the length d (d / w) of both widthwise ends 32A, 32B of flat portion 32 relative to the electrode width w of foil electrode 30 is set to be 0.6 or more. As described above, the inclination angles θ1, θ2 of the cross sections from both widthwise ends E1, E2 to both widthwise ends 32A, 32B of flat portion 32 are equal and constant, but the angles θ1, θ2 may be different.

[0040] The thickness t of the flat portion 32 is not strictly constant, and it is sufficient that the thickness t can be regarded as approximately flat while having slight curvatures, minute irregularities, etc. when observed under magnification. Here, the flat portion 32 is formed so that the thickness of any point along the electrode width direction of the flat portion 32 has a ratio of 0.7 or more to the maximum thickness of the foil electrode 30 (flat portion 32).

[0041] Such an electrode shape makes it possible to provide a compact excimer lamp 10 with excellent lighting startability while improving adhesion to the covering tube 60 and the outer tube 22 and suppressing peeling. Note that the shape of the foil electrode 30 shown in Fig. 2 is schematic and differs from the shape shown in Fig. 3.

[0042] First, electric field concentration occurs due to the sharply pointed edge E of the foil electrode 30 extending along the tube axis C. This allows discharge to occur while keeping the discharge initiation voltage low. In addition, because the wedge-shaped portions 34A and 34B have a sharply pointed wedge shape up to the edge E, the cross section of the foil electrode 30 near the edge E becomes linear in the axial direction, making it possible to keep the discharge initiation voltage lower and also making it less likely for a gap to form at the boundary between the covering tube 60 and the outer tube 22, and therefore less likely for peeling to occur.

[0043] On the other hand, by forming the flat portion 32 on the foil electrode 30, it is possible to improve the adhesion with the covering tube 60 and the outer tube 22 and suppress peeling. That is, by providing the flat portion 32 with a substantially constant thickness t, a relatively large cross-sectional area is ensured for the foil electrode 30 with an extremely thin thickness t. In particular, since the flat portion 32 occupies 60% or more of the foil electrode 30, the generation of Joule heat in the foil electrode 30 is suppressed by the current flowing through the flat portion 32 with a relatively large cross-sectional area during lamp operation.

[0044] As a result, thermal expansion of the foil electrode 30 in the thickness direction (Y direction) and width direction (X direction) can be suppressed. That is, there is no need to particularly increase the length of the foil electrode 30 in the width direction in order to ensure a large cross-sectional area, and large thermal expansion along the width direction can be prevented. In addition, there is no need to particularly increase the thickness of the foil electrode 30, so large thermal expansion along the thickness direction can be prevented.

[0045] Furthermore, the wedge-shaped portions 34A, 34B formed from both widthwise ends 32A, 32B of the flat portion 32 toward both widthwise ends E1, E2 of the foil electrode 30 respectively have a sharply pointed wedge shape up to the edge E, so that the electric field strength can be concentrated at the edge E of the foil electrode 30 while preventing peeling of the foil electrode 30 from the covering tube 60 and the outer tube 22.

[0046] Furthermore, by forming the wedge-shaped portions 34A, 34B with constant cross-sectional inclination angles θ1, θ2, it becomes easy to polish the surfaces of the wedge-shaped portions 34A, 34B by electrolytic polishing, etc. This makes it possible to suppress peeling at the boundaries with the covering tube 60 and the outer tube 22, and to achieve high illuminance of the hollow excimer lamp 10.

[0047] The width w of the foil electrode 30 is smaller than the outer diameter D10 of the inner tube 25 (inner tube small diameter portion 26). In other words, the width of the inner tube 25 along the width direction of the foil electrode 30 is wider than that of the foil electrode 30. As a result, when a discharge occurs in the discharge space S, due to the characteristics of the wedge shape of the foil electrode 30, a discharge is likely to be formed near the outer surface of the inner tube 25 close to the flow path R in the inner tube 25, and ultraviolet rays can be effectively irradiated to the fluid passing through the flow path R.

[0048] In the excimer lamp 10, the diameters of the inner tube 25 and outer tube 22 constituting the discharge tube 20 are set to sizes suitable for high illuminance. If the inner diameter D0 of the inner tube 25 is too large, the proportion of fluid passing through without being irradiated with ultraviolet rays increases, reducing the ultraviolet irradiation efficiency. On the other hand, if the inner diameter D0 of the inner tube 25 is too small, the flow rate decreases and the flow speed increases, reducing the ultraviolet irradiation efficiency.

[0049] In this embodiment, as described above, the inner diameter D20 of the outer tube 22 (outer tube large diameter section 24) is set to be 1.3 times or more the outer diameter D10 of the inner tube 25 (inner tube small diameter section 26). As a result, when the inner diameter D0 of the inner tube 25 is set to a certain size or more so as not to be too small, an appropriate volume of the discharge space S can be secured relative to the volume of the flow path R so as not to reduce the ultraviolet irradiation efficiency.

[0050] In order to improve the efficiency of ultraviolet irradiation, it is desirable to keep the size of the inner tube small diameter portion 26 small relative to the volume of the discharge space S. Such a reduction in the size of the inner tube small diameter portion 26 may reduce the mechanical strength of the discharge tube 20 that employs a double tube structure, leading to risk of breakage.

[0051] However, by providing the inner tube large diameter parts 27A, 27B near both ends of the discharge tube 20, the mechanical strength of the discharge tube 20 can be maintained. Also, with respect to the outer tube 22, the lead-in tube 21 is provided in the outer tube small diameter part 23 so as to be away from the electrode facing section K and to face the inner tube small diameter part 26 formed near the inner tube large diameter part 27A. This makes it possible to configure the lead-in tube 21 so as not to protrude in the lamp radial direction beyond the covering tube 60, and also makes it possible to improve the efficiency of exhausting and sealing impurity gases in the discharge tube 20 via the lead-in tube 21.

[0052] Even in the inner tube 25 having such inner tube small diameter section 26 and inner tube large diameter sections 27A, 27B, at least in the electrode opposing section K, the inner tube small diameter section 26 is not subjected to heat forming and has a substantially constant inner diameter D0. That is, in the electrode opposing section K where discharge occurs and ultraviolet rays are irradiated, the state of an unformed tube with small error is maintained and error between lamps is suppressed. Therefore, error between lamps in the efficiency of ultraviolet irradiation on the fluid flowing through the flow path R is suppressed, and a decrease in reliability can be prevented.

[0053] The above-described excimer lamp 10 can be manufactured, for example, by the following manufacturing method.

[0054] The inner tube small diameter section 26, inner tube large diameter sections 27A, 27B, flange-shaped sections M1, M2 of the inner tube 25, the introduction tube 21, outer tube small diameter section 23, outer tube large diameter section 24, and outer tube flange section M3 of the outer tube 22 are each heat-formed into a tubular member made of a dielectric material such as quartz glass. The discharge tube 20 forms a discharge space S by heating and shrinking both ends of the outer tube 22 to fuse them to the flange-shaped sections M1, M2 provided on the inner tube 25.

[0055] The covering tube 60 is a tubular member made of a dielectric material such as quartz glass with an inner diameter larger than the outer diameter of the discharge tube 20. The discharge tube 20, which has a foil electrode arranged on its outer peripheral surface, is inserted into the covering tube 60. The covering tube 60 is heated and reduced in diameter in a coaxial manner while the end 60T1 of the covering tube 60 and the outer tube flange M3 are brought into axial contact with each other. It is welded integrally to at least a portion of the outer circumferential surface of the outer pipe large diameter portion 24 .

[0056] Impurities are removed by drawing a vacuum inside the discharge tube 20 through the introduction tube 21. Thereafter, a discharge gas is sealed inside the discharge tube 20, and the introduction tube 21 is heated and melted to hermetically seal the inside of the discharge tube 20.

[0057] Next, an excimer lamp according to a second embodiment will be described with reference to Figures 4 and 5. In the second embodiment, an auxiliary discharge space is formed in a discharge tube.

[0058] Fig. 4 is a schematic cross-sectional view of an excimer lamp according to a second embodiment of the present invention, and Fig. 5 is a schematic cross-sectional view taken along line VV of Fig. 4.

[0059] As in the first embodiment, the excimer lamp 100 is configured as a hollow excimer lamp equipped with a discharge tube 20 formed by welding an outer tube 22 and an inner tube 2. A partially unwelded portion exists between the covering tube 160 and the outer tube 22, forming an auxiliary discharge space S1. One end 30T of the inner electrode 30 is exposed to the auxiliary discharge space S1.

[0060] The lighting startability can be improved by forming the auxiliary discharge space S1 in this way in the discharge tube 20. The excimer lamp 100 in which the auxiliary discharge space S1 is formed can be manufactured, for example, by the following manufacturing method.

[0061] In the manufacturing method of the excimer lamp of the first embodiment, when the covering tube 160, the end portion 160T1, and the outer tube flange portion M3 are abutted in the axial direction and coaxially heated and reduced in diameter, the covering tube 60 and the outer tube 22 are not welded to each other in the entire circumferential direction near one end portion 30T of the inner electrode 30, thereby making it possible to manufacture an excimer lamp 100 in which an auxiliary discharge space S1 is formed. [Explanation of symbols]

[0062] 10 Excimer Lamp 20 discharge tube 22 Outer tube 25 Inner tube 30 Inner electrode (foil electrode) 40 outer electrode 50 Insulating tube 60 Cladding tube

Claims

1. an outer tube having an outer electrode disposed on an outer surface thereof; an inner tube disposed coaxially within the outer tube; a foil-shaped inner electrode embedded between a covering tube covering at least a part of the outer tube and the outer tube, The excimer lamp according to claim 1, wherein the inner electrode has a flat portion having a substantially constant thickness along a width direction of the electrode, and is tapered from the flat portion toward both ends.

2. The inner tube is an inner pipe large diameter portion provided with a flange portion to be welded to the outer pipe; 2. The excimer lamp according to claim 1, further comprising an inner tube small diameter portion which is formed closer to the discharge space than the inner tube large diameter portion and has a smaller diameter than the inner tube large diameter portion.

3. the outer pipe has an outer pipe small diameter portion that is not covered by the cladding pipe and has a diameter smaller than that of a portion covered by the cladding pipe, 3. The excimer lamp according to claim 2, wherein the outer tube small diameter portion faces at least a portion of the inner tube small diameter portion.

4. 2. The excimer lamp of claim 1, wherein the thickness of said inner tube is less than the thicknesses of said outer tube and said cladding tube.

5. 2. The excimer lamp according to claim 1, wherein the electrode width of the inner electrode is smaller than the outer diameter of the inner tube.

6. 2. The excimer lamp according to claim 1, wherein the inner diameter of the outer tube is at least 1.3 times the outer diameter of the inner tube.

7. 2. The excimer lamp according to claim 1, wherein an ultraviolet reflective film is formed on the inner surface of the outer tube in a portion corresponding to a section facing the inner electrode.

8. The cladding tube is partially fused to the outer tube, 2. The excimer lamp according to claim 1, wherein an auxiliary discharge space is formed in a non-welded portion between said covering tube and said outer tube.

9. 9. The excimer lamp according to claim 8, wherein a portion of the inner electrode is exposed to the auxiliary discharge space.

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