Excimer lamp

Abstract

To provide a spot radiation type excimer lamp which effectively radiates light such as ultraviolet rays to a radiation target object.SOLUTION: An excimer lamp 10 includes: a discharge pipe 20; a foil electrode 30 extending along a pipe shaft C in the discharge pipe 20; an external electrode 40 covering the outer surface of the discharge pipe 20; and a dielectric 50 covering the foil electrode 30. The dielectric 50 is flat in the width direction (Y-direction) of the foil electrode 30.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an excimer lamp, and more particularly to an excimer lamp that irradiates light in the lamp axial direction (hereinafter referred to as a spot irradiation type excimer lamp). [Background technology]

[0002] In a spot irradiation type excimer lamp, one end of the discharge tube is used as the light emission surface (exit surface), and a film-like outer electrode (such as an aluminum film) that reflects ultraviolet rays is provided to cover the outer surface of the discharge tube (see, for example, Patent Document 1).

[0003] Excimer light is emitted from a discharge generated by applying a high-frequency voltage between an inner electrode and an outer electrode provided inside the discharge tube. The excimer light is reflected by the outer electrode and guided to the emission surface of the discharge tube, and is also guided to the emission surface by the fiber effect, which allows ultraviolet light to pass through the wall of the discharge tube, causing the ultraviolet light to be emitted from the lamp emission surface. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6557011 Summary of the Invention [Problem to be solved by the invention]

[0005] For example, when configuring a small spot irradiation type excimer lamp (for example, the outer diameter of the discharge vessel is several mm to several tens of mm), it may be necessary to place the irradiation object in close proximity and irradiate light such as ultraviolet light in a concentrated manner. Even in such a case, it is required to irradiate light effectively. [Means for solving the problem]

[0006] The excimer lamp according to one aspect of the present invention comprises a discharge tube having a light emitting surface at one end thereof, and a dielectric covering a foil electrode extending in a strip shape within the discharge tube. The foil electrode can be disposed so as to extend, for example, in the direction of the tube axis (lamp axis) of the tubular discharge vessel.

[0007] The foil electrode may be configured in various ways, and may be configured such that both ends along the width direction of the foil electrode are thinner than the center portion along the width direction of the foil electrode. For example, the foil electrode may have a flat portion between both ends along the width direction of the foil electrode, the thickness of which is approximately constant along the width direction, and the foil electrode may be configured to be sharpened from both ends of the flat portion toward both ends along the width direction of the foil electrode.

[0008] In the excimer lamp of the present invention, the dielectric is flat to match the width direction of the foil electrode. Here, "flat to match the width direction of the foil electrode" means that the dielectric is elongated along the width direction of the foil electrode and has a flat surface portion with a substantially constant thickness along the thickness direction of the foil electrode. This flat shape can be said to be a shape that is achieved by flattening the foil electrode in the thickness direction.

[0009] The arrangement of the dielectric and foil electrode can be varied, and the foil electrode can be arranged coaxially relative to the dielectric, and the distance between the outer surface of the dielectric and the foil electrode along the thickness direction of the foil electrode is shorter than the distance between the outer surface of the dielectric and the foil electrode along the width direction of the foil electrode.

[0010] The dielectric may be configured so that its flat shape is determined based on the position of the foil electrode, i.e., the width direction. For example, the dielectric may be configured so that it has an outer surface that is substantially parallel to the width direction of the foil electrode. Also, the dielectric may be configured so that it has an outer surface that is substantially perpendicular to the emission surface.

[0011] The dielectric may be of various shapes as a specific flat shape. For example, the cross section of the dielectric may be oval or oblong. The dielectric may have a small diameter portion formed inside the discharge tube and a large diameter portion formed outside the discharge tube, and the diameter of the small diameter portion along the width direction and thickness direction of the foil electrode may be smaller than the diameter of the large diameter portion. Effect of the Invention

[0012] According to the present invention, in a spot irradiation type excimer lamp, light can be effectively irradiated toward an irradiation object. [Brief description of the drawings]

[0013] [Figure 1] 1 is a schematic cross-sectional view taken along the electrode width direction of an excimer lamp according to an embodiment of the present invention. [Diagram 2] 1 is a schematic side view of an excimer lamp according to the present embodiment, as viewed from the emission surface side. [Diagram 3] 1 is a cross-sectional view taken along the electrode thickness direction of an excimer lamp according to an embodiment of the present invention. [Figure 4] FIG. 2 is an enlarged cross-sectional view of a foil electrode. [Diagram 5] FIG. 4 is an enlarged cross-sectional view of a foil electrode and a dielectric covering the foil electrode. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an excimer lamp according to the present embodiment will be described with reference to the drawings.

[0015] Fig. 1 is a schematic cross-sectional view of the excimer lamp according to the present embodiment taken along the electrode width direction. Fig. 2 is a schematic side view of the excimer lamp according to the present embodiment taken from the emission surface side. Fig. 3 is a cross-sectional view of the excimer lamp according to the present embodiment taken along the electrode thickness direction.

[0016] The excimer lamp 10 is a spot irradiation type excimer lamp, and is configured here as a small spot irradiation type excimer lamp. The excimer lamp 10 includes a cylindrical discharge tube (discharge vessel) 20 with a bottom made of a dielectric material such as quartz glass, and one end, which is the bottom portion of the cylindrical discharge tube 20 with a bottom, is configured as an emission surface (emission surface) 20D of light including ultraviolet rays.

[0017] Here, the discharge tube 20 is configured as a discharge tube with a circular cross section along the tube diameter (lamp diameter) direction, and is configured so that the inner diameter and thickness are constant along the tube axis (lamp axis) C. A rare gas such as xenon gas or a mixed gas of these is sealed in the discharge space S inside the discharge tube 20 as a discharge gas. An emission surface 20D of the discharge tube 20 is made of a material that transmits light radiated from a discharge generated in the discharge space S.

[0018] A foil electrode 30 extending in a strip shape along the tube axis C is disposed within the discharge tube 20. The foil electrode 30 is covered (sealed) by a columnar dielectric 50 made of quartz glass or the like, and is embedded within the dielectric 50 without being exposed to the discharge space S. One end 30T of the foil electrode 30 along the lamp axis C is connected to a power supply line (power supply rod) 60, which is connected to an externally installed power supply unit (not shown).

[0019] The dielectric 50 is welded to the discharge tube 20 at a flange portion (hereinafter referred to as a welded portion) 52 that protrudes radially like a flange, and constitutes the inner tube of the excimer lamp 10, which is a double-tube lamp. The size of the outer diameter of the welded portion 52 of the dielectric 50 is determined according to the inner diameter D1 of the discharge tube 20.

[0020] 2, the foil electrode 30 is arranged coaxially with respect to the discharge tube 20, and the dielectric 50 is also arranged coaxially with respect to the discharge tube 20. Therefore, the foil electrode 30 is arranged coaxially with its center position in the width direction and thickness direction aligned with the center position of the dielectric 50. Also, they are arranged symmetrically with respect to the tube axis C. In FIGS. 1 to 3, the width direction of the foil electrode 30 is defined as the Y direction, and the direction perpendicular thereto (thickness direction) is defined as the X direction.

[0021] An outer electrode 40 is provided on the outer surface 20S of the discharge tube 20. The outer electrode 40 is made of a material that reflects light such as ultraviolet light emitted from the discharge generated in the discharge space S, and is formed, for example, of a film or plate that has thermal conductivity and electrical conductivity. Here, the outer electrode 40 covers the outer surface 20S of the discharge tube 20 except for the emission surface 20D. The outer electrode 40 can be formed, for example, of a film (such as an aluminum film) that reflects light including ultraviolet light with a wavelength of 172 nm.

[0022] When a high-frequency voltage (e.g., a voltage in the range of several kV to several tens of kV at a frequency of several kHz to several tens of MHz) is applied between the foil electrode 30 and the outer electrode 40, a dielectric barrier discharge is generated between the outer surface of the dielectric 50 covering the foil electrode 30 and the inner surface of the discharge tube 20 covered by the outer electrode 40, and excimer light of a predetermined spectrum (e.g., a wavelength of 172 nm) is radiated from the discharge space S.

[0023] The light emitted from the discharge space S is reflected by the outer electrode 40, and is guided to the emission surface 20D side by the fiber effect of the dielectric 50 and the discharge tube 20, and is emitted from the emission surface 20D. By arranging an irradiation target opposite the emission surface 20D, it is possible to perform light irradiation, ultraviolet irradiation, and the like.

[0024] The size of the small spot irradiation type excimer lamp 10 can be determined according to the usage environment, etc. For example, the axial length (light emission length) in which discharge occurs in the discharge tube 20 can be set in the range of 20 mm to 400 mm. The outer diameter of the discharge tube 20 can be set in the range of 5 mm to 30 mm, preferably in the range of 8 mm to 25 mm.

[0025] The thickness of the discharge tube 20 can be set in the range of, for example, 0.8 mm to 1.5 mm, taking into consideration prevention of discharge tube deterioration due to excimer light and suppression of an increase in discharge start voltage.

[0026] The discharge distance, i.e., the distance between the dielectric 50 and the inner diameter of the discharge tube 20, can be set in the range of 2 mm to 12 mm, preferably in the range of 3 mm to 10 mm, taking into consideration prevention of insufficient illuminance due to narrowing of the discharge space and prevention of instability of the discharge due to increase in the discharge distance.

[0027] The foil electrode 30 is configured as an extremely thin strip-shaped electrode with a thickness that is suppressed relative to the electrode width. Here, the thickness of the foil electrode 30 relative to the electrode width is set to 1 / 30 or less, preferably 1 / 50 or less, and more preferably 1 / 100 or less. Note that the thickness of the foil electrode 30 is exaggerated in Figs. 2 and 3.

[0028] For example, the thickness of the foil electrode 30 can be set in the range of 20 μm to 50 μm, taking into consideration the current capacity, ease of manufacture, and prevention of peeling from the dielectric 50. On the other hand, the width of the foil electrode 30 can be set in the range of 1.2 mm to 10 mm, taking into consideration the current capacity, ease of manufacture, prevention of blocking of discharge light due to an increase in the electrode area, and the like.

[0029] The electrode material of the foil electrode 30 can be formed from a highly conductive metal or alloy. It can also be made from a material that is easy to electropolish. In this example, molybdenum or an alloy containing molybdenum is used.

[0030] Here, the dielectric 50 is made of a dielectric material (such as SiO2). The thickness of the dielectric 50 can be set in the range of, for example, 0.1 mm to 2 mm, taking into consideration the limit for maintaining the insulation property and the prevention of an increase in the discharge start voltage.

[0031] 2, the dielectric 50 is formed to be flat along the tube axis C. The dielectric 50 has a substantially constant thickness along the width direction (Y direction) of the foil electrode 30. Therefore, it can be said that the dielectric 50 is composed of a rectangular columnar portion having a substantially constant thickness along the width direction (Y direction) of the foil electrode 30, and semi-circular columnar portions integrally formed at both ends of the rectangular columnar portion.

[0032] Since the dielectric 50 is flattened in the thickness direction (X direction) of the foil electrode 30 and has an elongated flat shape in the width direction (Y direction) of the foil electrode 30, the outer diameter W21 (FIG. 3) along the thickness direction (X direction) of the foil electrode 30 is smaller than the outer diameter W11 (FIG. 1) along the width direction (Y direction) of the foil electrode 30. Therefore, the distance D21 (FIG. 3) between the discharge tube inner surface 20M along the thickness direction (X direction) of the foil electrode 30 and the outer surface of the dielectric is longer than the distance D11 (FIG. 1) along the width direction (Y direction) of the foil electrode 30.

[0033] 1 and 3, dielectric 50 includes a portion (hereinafter referred to as small diameter portion) 53 formed inside the discharge tube so as to extend toward discharge space side S with welded portion 52 in between, and a portion (hereinafter referred to as large diameter portion) 55 formed outside the discharge tube so as to protrude from welded portion 52 toward power supply line 60. The position along the tube axis C of connection portion 54 connecting small diameter portion 53 and welded portion 52 of dielectric 50 corresponds to end portion 30T of foil electrode 30.

[0034] FIG. 4 is an enlarged cross-sectional view of the foil electrode 30. As shown in FIG.

[0035] As described above, the foil electrode 30 is an electrode formed with a very thin thickness compared to the foil electrode width w, and the thickness t of the foil electrode width w is suppressed to 1 / 30 or less. The foil electrode 30 has a flat portion 32 with a constant thickness (=t), and has wedge-shaped portions 34A, 34B that taper from both widthwise ends (both ends along the width direction) 32A, 32B of the flat portion 32 to both widthwise ends E1, E2 of the foil electrode 30.

[0036] For example, the angles θ1, θ2 (angle θ of edge E) of both ends E1, E2 in the width direction of the foil electrode 30 can be set in the range of 2° to 15°, preferably 10° or less, by considering the difficulty of peeling due to gaps generated at the boundary with the dielectric to be covered, the size of the cross-sectional area of ​​the flat part according to the current capacity, and the suppression of temperature rise due to Joule heat generation. The inclination angle of the cross section of the flat part 32 can be set in the range of less than 2°. This angle θ can be determined from the angle at which the thickness increases from the edge E of the foil electrode toward the flat part 32 by enlarging and observing the cross section of the foil electrode 30 in the vicinity of a range of about 100 μm from the edge E. As a result, in the foil electrode 30, an edge-like edge E is formed over the entire electrode along the tube axis C direction.

[0037] The flat portion 32 is formed so that its widthwise center (central portion) coincides with the tube axis C, and the wedge-shaped portions 34A, 34B are symmetrical with respect to the flat portion 32. Furthermore, the widthwise length d1 (d1 / w) of the wedge-shaped portions 34A, 34B relative to the electrode width w of the foil electrode 30 is set to 0.2 or less. Here, the wedge-shaped portions 34A, 34B are formed so that the inclination angles θ of the cross sections from both widthwise ends to both widthwise ends 32A, 32B of the flat portion 32 are constant.

[0038] Furthermore, the flat portion 32 is formed to have a thickness that is 70% or more of the maximum thickness T of the foil electrode 30. For example, the length d (d / w) between both ends 32A, 32B in the width direction of the flat portion 32 relative to the electrode width w of the foil electrode 30 is set to be 0.6 or more.

[0039] FIG. 5 is an enlarged cross-sectional view of the foil electrode 30 and the dielectric 50 covering the foil electrode 30. As shown in FIG.

[0040] As described above, the dielectric 50 has a flat shape along the tube axis C, and the cross section of the dielectric 50 is an oblong or oval shape. The dielectric 50 has a substantially uniform cross-sectional shape over the range covering the foil electrode 30 along the tube axis (lamp axis) C.

[0041] The cross-sectional shape of such dielectric 50, which is oblong or elliptical, is a cross-sectional shape that matches the arrangement and shape of foil electrode 30 shown in Figure 4, and minimizes the difference in the distance from any surface of foil electrode 30 to outer surface 50S of dielectric 50 (thickness to the foil electrode).

[0042] Here, a central portion (flat portion) 50M0 refers to a portion of section M0 in which a planar (flat) outer surface 50S1 of a quadrangular columnar portion that is approximately parallel to the flat portion 32 of the foil electrode 30 and approximately perpendicular to the emission surface 20D of the discharge tube 20 is formed. Also, a portion of section M1 in which a curved (semi-ellipsoidal) outer surface 50S2 of a semi-cylindrical portion that is convex from both ends of the central portion 50M0 toward the outside in the electrode width direction (Y direction) is formed is referred to as both end portions (curved portions) 50M1.

[0043] The quadrangular columnar portion has a cross section along the lamp radial direction that approximates a quadrangle such as a square or a rectangle, and is a columnar body with a uniform cross-sectional shape along the tube axis C direction that is approximately parallel to the flat portion 32 of the foil electrode. A pair of these quadrangular columnar portions cover the vicinity of the center in the width direction of the foil electrode from both sides in the electrode thickness direction so that the thickness T2 is approximately constant.

[0044] The semi-cylindrical portion is a semi-cylindrical body whose cross section along the lamp radial direction is approximating a semicircle such as a semi-ellipse and has a uniform cross-sectional shape along the tube axis C. A pair of these semi-cylindrical portions cover the vicinity of the edge in the width direction of the foil electrode from both sides in the electrode width direction, with a thickness T1 in the electrode width direction and a thickness T2 in the electrode thickness direction, so as to surround the vicinity of the edge at the center.

[0045] The boundaries between the central portion (flat portion) 50M0 and both end portions (curved portions) 50M1 of the dielectric 50 are located along the width direction (Y direction) of the foil electrode 30 closer to the center in the width direction (tube axis C) of the foil electrode 30 than both ends E1, E2 of the foil electrode 30, preferably the width direction ends 32A, 32B of the flat portion 32. That is, the length of section M0 along the width direction (Y direction) of the foil electrode is set to be smaller than w, preferably smaller than d. Also, the length of section M1 is formed to be larger than T1.

[0046] As described above, the dielectric 50 that constitutes the double-tube lamp by welding with the discharge tube 20 has a small diameter portion 53 and a large diameter portion 55. The outer diameter W11 (see FIG. 1) of the small diameter portion 53 along the width direction (Y direction) of the foil electrode 30 and the outer diameter W21 (see FIG. 3) along the thickness direction (X direction) are both smaller than the outer diameter W12 of the large diameter portion 55 that has a circular cross section.

[0047] Here, the outer diameter W11 of the dielectric 50 along the width direction (Y direction) of the foil electrode 30 is set to be 3 / 4 or less of the inner diameter D1 of the discharge tube 20, preferably 1 / 2 or less.

[0048] According to the excimer lamp 10 of this embodiment described above, the dielectric 50 is configured to be flat, so that the light radiation efficiency of the spot irradiation type excimer lamp 10 is increased.

[0049] That is, because dielectric 50 has a flat shape, the cross-sectional area is smaller than that of a dielectric having a circular cross section, ensuring the volume of discharge space S. That is, the cross-sectional area of ​​discharge space S is large along the thickness direction (X direction) of foil electrode 30 when viewed from the emission surface 20D side.

[0050] Therefore, it is possible to suppress attenuation of the light reflected by the outer electrode 40 while being guided to the emission surface 20D along the tube axis C. This makes it possible to configure an excimer lamp 10 that is long in the axial direction even though it is small, and enables high illuminance to be achieved while greatly adjusting the length of the discharge tube 20 along the tube axis C.

[0051] Furthermore, since the dielectric 50 is flat, uniformity in the illuminance distribution is achieved along the thickness direction (X direction) of the foil electrode 30. That is, for an electrode structure in which the foil electrode 30 is provided with the flat portion 32, the distance to the outer surface 50S of the dielectric 50, i.e., the thickness along the thickness direction (X direction) of the foil electrode 30, is approximately constant along the width direction (Y direction) of the foil electrode 30.

[0052] Therefore, it is possible to suppress the occurrence of uneven discharge in the width direction (Y direction) of the foil electrode 30, and in particular, to suppress the decrease in illuminance near the center. This makes it possible to increase the area of ​​the emission surface 20D (the volume of the discharge tube 20) while achieving a uniform illuminance distribution.

[0053] Furthermore, small diameter portion 53 of dielectric 50 that is disposed inside discharge tube 20, i.e., disposed inside discharge space S, has a diameter W11 that is smaller than large diameter portion 55 outside discharge space S. This makes it possible to ensure a larger volume of discharge space S, and light radiated from a discharge generated in discharge space S is guided with reduced attenuation as it travels toward emission surface 20D due to the fiber effect of dielectric 50 and discharge tube 20 and reflection by outer electrode 40.

[0054] On the other hand, the foil electrode 30 forms wedge shapes 34A, 34B that are sharpened toward both ends E1, E2 in the width direction, and the dielectric 50 is flattened along the width direction (Y direction) of the foil electrode 30. Therefore, even if the area of ​​the emission surface 20D (the volume of the discharge tube 20) is large, the discharge start voltage can be set low by electric field concentration, and good lighting startability can be maintained.

[0055] In addition, the wedge shapes 34A and 34B of the foil electrode 30 allow the foil electrode 30 to adhere closely to the dielectric 50, making it difficult for gaps to form at the boundary with the dielectric 50 and difficult for peeling to occur. Furthermore, forming the flat portion 32 on the foil electrode 30 can increase the adhesion between the foil electrode 30 and the dielectric 50 and suppress peeling. As a result, attenuation of the light due to the fiber effect while traveling inside the dielectric 50 toward the emission surface 20D can be suppressed, and the illuminance of the light can be improved.

[0056] The excimer lamp 10 having such a dielectric 50 can be manufactured, for example, by the following manufacturing method.

[0057] First, the power supply wire is connected to the foil electrode by resistance welding or the like, and then inserted into the glass tube that will become the dielectric coating material. After inserting the foil electrode, the glass tube is evacuated, and then the dielectric coating material is heated from the outside to seal it with the foil electrode. At this time, the heating is adjusted so that the cross-sectional shape of the dielectric 50 described above is obtained.

[0058] For example, by rotating the glass tube and heating it with a burner or the like, the glass tube is uniformly circumferentially contracted (reduced in diameter) until the inner surface of the glass tube comes into contact with both ends (wedge-shaped portions) of the foil electrode, and the glass tube between the portions in contact with both ends (wedge-shaped portions) of the foil electrode is contracted along the thickness direction of the foil electrode to be integrated with the flat portion, thereby making it possible to form a dielectric having an oblong or elliptical cross section. Note that a process of coating a dielectric or a process of cutting the glass tube may be performed instead.

[0059] A brim-shaped, so-called bead-shaped seal is formed at a position on the glass tube that corresponds to the edge of the electrode along the tube axis. A discharge tube made of quartz glass or the like is then formed with an exhaust tube at one end and an insertion port at the other end. A dielectric with a foil electrode sealed thereto is inserted into the discharge tube, and the insertion port of the discharge tube is fused to the bead-shaped seal.

[0060] While heating the entire discharge tube, a vacuum is drawn through the exhaust tube to remove impurities. After filling the discharge gas, the exhaust tube is sealed and an outer electrode is provided on the outer surface of the discharge tube. At this time, the outer electrode is formed directly on the outer surface of the discharge tube by sputtering after masking the area that will become the emission surface and irradiating the area where the outer electrode will be provided with ultraviolet light for surface treatment.

[0061] In the excimer lamp 10 of the present embodiment described above, the dielectric 50 is configured to be flat, but it is also possible to configure it to be elliptical. That is, the dielectric 50 having an elliptical cross section may be formed along the tube axis C. Moreover, the dielectric 50 is not limited to being flat over its entirety, and may be configured to be partially flat. For example, only the portion covering a part of the inner electrode 30 may be flat.

[0062] The foil electrode 30 may be configured without the flat portion 32 or without the wedge shapes 34A, 34B. It is sufficient to configure the electrode so that the thickness at the ends is smaller than that at the center in the electrode width direction (Y direction).

[0063] The thickness T2 of the foil electrode 30 can be determined according to the area of ​​the emission surface 20D of the discharge tube 20, i.e., the inner diameter D1, taking into consideration the uniformity of the illuminance distribution along the thickness direction (X direction) of the foil electrode 30. For example, it can be determined to be 1 / 200 or less of the inner diameter D1 of the emission surface 20D.

[0064] Also, the width W of the foil electrode 30 can be determined in consideration of lighting startability due to electric field concentration, etc., according to the area of ​​the emission surface 20D of the discharge tube 20, i.e., the inner diameter D1. For example, the width W of the foil electrode 30 can be determined to be 1 / 2 or less, preferably 1 / 4 or less, of the inner diameter D1 of the emission surface 20D.

[0065] The outer electrode 40 may be configured with an electrode configuration other than an aluminum film, and may be configured to reflect light by providing a material or member capable of reflecting light rather than by the outer electrode 40 alone. Furthermore, light may be reflected by a material or member other than the outer electrode 40. Instead of emitting ultraviolet light from the emission surface, the emission surface may be configured to emit visible light emitted from discharge or phosphors. [Explanation of symbols]

[0066] 10 Excimer Lamp 20 discharge tube 20D emission surface 30 Inner electrode (foil electrode) 40 outer electrode 50 Dielectric

Claims

1. A discharge tube having a light emitting surface formed at one end thereof; a dielectric covering the foil electrodes extending in a strip shape within the discharge tube; 2. A spot irradiation type excimer lamp, wherein the dielectric is flat in shape to match the width direction of the foil electrode.

2. 2. The excimer lamp according to claim 1, wherein the dielectric has an outer surface that is approximately parallel to the width direction of the foil electrode.

3. 2. The excimer lamp of claim 1, wherein the dielectric has a planar outer surface substantially perpendicular to the emission surface.

4. 2. The excimer lamp according to claim 1, wherein the cross section of the dielectric body is elliptical or oblong.

5. the dielectric body has a small diameter portion formed inside the discharge tube and a large diameter portion formed outside the discharge tube, 2. The excimer lamp according to claim 1, wherein the diameter of the small diameter portion along the width and thickness directions of the foil electrode is smaller than the diameter of the large diameter portion.

6. The excimer lamp described in claim 1, characterized in that the foil electrode has a flat portion having a substantially constant thickness along the width direction between both ends of the foil electrode along the width direction, and is sharpened from both ends of the flat portion toward both ends of the foil electrode along the width direction.

7. the foil electrode is disposed coaxially with respect to the dielectric; An excimer lamp as described in any one of claims 1 to 6, characterized in that the distance between the outer surface of the dielectric and the foil electrode along the thickness direction of the foil electrode is shorter than the distance between the outer surface of the dielectric and the foil electrode along the width direction of the foil electrode.

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