Excimer lamp

Abstract

To provide a line radiation type excimer lamp which efficiently radiates light such as ultraviolet rays discharged in a discharge pipe to a radiation target object.SOLUTION: In a discharge tube 20 of an excimer lamp 10, an outside surface 20S is covered by an external electrode 40 and a part of the outside surface which is not covered by the external electrode 40 is used as a window 20W for light transmission. A foil electrode 30 forms wedge shape 34A and 34B sharpened to both ends E1 and E2 in the width direction, the end E2 facing the external electrode 40 and the end E1 facing the window 20W.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an excimer lamp, and more particularly to an excimer lamp capable of irradiating an object with light such as ultraviolet light with high efficiency. [Background technology]

[0002] In an excimer lamp, an inner electrode is placed inside a discharge tube filled with a rare gas such as xenon or a mixed gas containing a rare gas, and an outer electrode is placed on the outer surface of the discharge tube. A discharge is generated by applying a high-frequency voltage between the inner and outer electrodes, and excimer light (ultraviolet rays) is emitted from the discharge space.

[0003] In order to irradiate light efficiently, an excimer lamp is known in which a part of the outer surface of the discharge tube is covered with an outer electrode having reflective properties, and light is emitted from a light-transmitting part where no outer electrode is provided. For example, a slit-shaped light-transmitting part is defined along the lamp axis direction, and the remaining part of the outer surface of the discharge tube is covered with an outer electrode such as an aluminum reflective film (see Patent Document 1). Hereinafter, such an excimer lamp is referred to as a line-irradiation type excimer lamp. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP-A-7-272692 (Fig. 7, etc.) Summary of the Invention [Problem to be solved by the invention]

[0005] When configuring a small line-emission type excimer lamp (for example, one having an outer diameter of a discharge tube of several mm to several tens of mm), it is necessary to more efficiently irradiate the light emitted from the discharge in the discharge tube toward an object to be irradiated. [Means for solving the problem]

[0006] The line-illumination type excimer lamp according to one aspect of the present invention is configured as an excimer lamp in which a light emitting surface is provided along the lamp axis direction in accordance with a slit-shaped light transmitting portion determined along the lamp axis direction. The excimer lamp includes a discharge tube, a dielectric covering an inner electrode extending in a band shape within the discharge tube, and an outer electrode provided along the circumferential direction of the outer surface of the discharge tube. For example, the outer electrode can be provided in a cross-sectional arc shape on a part of the circumferential direction of the outer surface of the discharge tube in order to irradiate a line of light transmitted through the slit-shaped light emitting surface. The arrangement area along the circumferential direction of the outer electrode, i.e., the light irradiation width, is arbitrary depending on the lamp size, light output, usage environment, etc.

[0007] The inner electrode may be configured in various ways, for example, as a foil electrode extending along the lamp axis. The foil electrode may be configured so that both ends along the electrode width direction are thinner than the central portion of the foil electrode in the width direction. For example, the foil electrode may be configured so that it has a flat portion with a substantially constant thickness along the width direction between both ends along the foil electrode in the width direction, and is sharpened from both ends of the flat portion toward both ends along the foil electrode in the width direction.

[0008] In the excimer lamp of the present invention, at least one end along the width direction of the band-shaped inner electrode faces the outer electrode. For example, it is possible to arrange the outer electrode so that the other end along the width direction of the inner electrode faces the emission surface of the discharge tube. Also, the emission surface of the discharge tube is formed symmetrically with respect to the width direction of the inner electrode. In other words, it is possible to configure the outer electrode so that it is symmetric with respect to the width direction of the inner electrode.

[0009] The dielectric may have various shapes, for example, the inner electrode may be configured to be coaxially disposed with respect to the dielectric, and the distance between the outer surface of the dielectric and the inner electrode along the thickness direction of the inner electrode may be shorter than the distance between the outer surface of the dielectric and the inner electrode along the width direction of the inner electrode.

[0010] For example, when the inner electrode is a foil electrode, the foil electrode can form a flat portion having a substantially constant thickness along the width direction between both ends of the foil electrode in the width direction, and the dielectric can be provided with an outer surface having a substantially constant thickness along the width direction of the foil electrode and substantially parallel to the flat portion.

[0011] A dielectric having such characteristics can be, for example, flat to match the width direction of the inner electrode. Here, "flat to match the width direction of the inner electrode" refers to a shape that has a flat outer surface along the width direction of the strip-shaped inner electrode and is flattened in the electrode thickness direction. Also, the dielectric can be configured so that the cross section of the dielectric is oval or oblong. Effect of the Invention

[0012] According to the present invention, in a line-emission type excimer lamp, light emitted from a discharge in a discharge tube can be efficiently directed toward an object to be irradiated. [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 cross-sectional view taken along the electrode thickness direction of an excimer lamp according to the present embodiment. [Diagram 3] FIG. 2 is a plan view of the excimer lamp as viewed from the radiation surface side. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Diagram 5] FIG. 2 is an enlarged cross-sectional view of a foil electrode. [Figure 6] 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 an excimer lamp along the electrode width direction. Fig. 2 is a schematic cross-sectional view of an excimer lamp along the electrode thickness direction. Fig. 3 is a plan view of the excimer lamp as viewed from the irradiation surface side. Fig. 4 is a cross-sectional view along IV-IV in Fig. 3.

[0016] The excimer lamp 10 is configured as a line irradiation type excimer lamp that emits light from a light transmitting portion determined along the lamp axis. 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 a window 20W is configured on a part of the cylindrical side surface of the cylindrical discharge tube 20 with a bottom as a light emission surface (exit surface).

[0017] The discharge tube 20 here is configured as a discharge tube having 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.

[0018] An electrode (inner electrode) extending in a strip shape along the tube axis C is arranged inside the discharge tube 20. Here, a foil electrode 30 is arranged along the tube axis C. The foil electrode 30 is covered (sealed) by a columnar dielectric 50 made of quartz glass or the like, and is embedded in 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, and the power supply line 60 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] As shown in Fig. 4, 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 4, 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 radiated from the discharge generated in the discharge space S, and is formed, for example, of a thermally and electrically conductive film or plate. Here, the outer surface portion of the discharge tube 20 that is not covered by the outer electrode 40 is formed as a window 20W for emitting light. 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 through the dielectric 50 covering the foil electrode 30 and the discharge tube 20 covered by the outer electrode, 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 emitted to the outside of the lamp through the window 20W either directly or by reflection from the outer electrode 40. By arranging an object to be irradiated in the vicinity of the window 20W so as to face the window 20W, it becomes possible to perform light irradiation, ultraviolet irradiation, and the like.

[0024] The size of the small line irradiation type excimer lamp 10 can be determined according to the usage environment, etc. For example, the axial length (light emission length) where 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 band-shaped electrode with a thickness 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 to 4.

[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] Dielectric 50 has a flat shape with a substantially constant thickness along the width direction (Y direction) of foil electrode 30 (see Figs. 4 and 6), and is formed to be flat throughout discharge space S. It can also be said that dielectric 50 is composed of a rectangular columnar portion with a substantially constant thickness along the width direction (Y direction) of foil electrode 30, and semicircular columnar portions integrally formed at both ends of the rectangular columnar portion.

[0032] Since dielectric 50 is flattened along the thickness direction (X direction) of foil electrode 30, an outer diameter W21 (FIG. 2) along the thickness direction (X direction) of foil electrode 30 is smaller than an outer diameter W11 (FIG. 1) along the width direction (Y direction) of foil electrode 30. As a result, distance D21 (FIG. 2) between discharge tube inner surface 20M along the thickness direction (X direction) of foil electrode 30 and the outer surface of the dielectric is longer than distance D11 (FIG. 1) between foil electrode 30 and the outer surface of the dielectric along the width direction (Y direction).

[0033] 1 and 2, 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] A protruding portion (hereinafter referred to as exhaust tube) 22 is formed at the end of the discharge tube 20. The exhaust tube 22 is a part formed in the lamp manufacturing process, in which the tip side of a glass tube, which is the material of the outer tube, is heated and deformed to reduce its diameter, and a tip tube smaller than the glass tube is fused to form the exhaust tube 22 as a single unit.

[0035] The outer electrode 40 covers the outer surface 20S of the discharge tube 20, excluding the window 20W, including the exhaust tube 22. Here, the area occupied by the window 20W on the outer surface of the discharge tube is defined as half the area in the circumferential direction of the discharge tube 20, relative to the section (discharge section) where the foil electrode 30 and the outer electrode 40 face each other along the lamp axis C (see FIG. 4).

[0036] Dielectric 50, which constitutes a double-tube lamp by welding with discharge tube 20, has a small diameter portion 53 and a large diameter portion 55. An outer diameter W1 (see FIG. 1) of small diameter portion 53 along the width direction (Y direction) of foil electrode 30 and an outer diameter W2 (see FIG. 2) along the thickness direction (X direction) are both smaller than an outer diameter W12 of large diameter portion 55, which has a circular cross section. Here, outer diameter W1 of dielectric 50 along the width direction (Y direction) of foil electrode 30 is set to be 3 / 4 or less, preferably 1 / 2 or less, of inner diameter D1 of discharge tube 20.

[0037] FIG. 5 is an enlarged cross-sectional view of the foil electrode 30. As shown in FIG.

[0038] As described above, the foil electrode 30 is an electrode formed to be extremely thin 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 of constant thickness (= t), and has wedge-shaped portions 34A, 34B that taper from both widthwise ends 32A, 32B of the flat portion 32 to both widthwise ends E1, E2 of the foil electrode 30.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] FIG. 6 is an enlarged cross-sectional view of the foil electrode 30 and the dielectric 50 covering the foil electrode 30. As shown in FIG.

[0043] 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 5, 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).

[0044] Here, a central portion (flat portion) 50M02 is defined as a portion of section M0 where a planar (flat surface) 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 where a curved (semi-ellipsoidal) outer surface 50S2 of a semi-cylinder portion that is convex from both ends of the central portion 50M02 toward the outside in the electrode width direction (Y direction) is formed is defined as both end portions (curved portions) 50M1.

[0045] 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.

[0046] The semi-cylinder portion is a semi-cylinder 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-cylinder 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.

[0047] 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.

[0048] For such a configuration of foil electrode 30 and dielectric 50, a window 20W that allows efficient light emission is formed in the outer surface 20S of the discharge tube 20.

[0049] As described above, the outer surface portion of the discharge tube 20 that is not covered by the outer electrode 40 serves as the window 20W for emitting light. Here, half the circumferential area of ​​the discharge tube 20 is formed as the window 20W. To explain in more detail, the outer electrode 40 has shielding portions 40M1, 40M2 that cover the entire outer surface 20S of the discharge tube 20 in the circumferential direction on the exhaust pipe 22 side and the power supply line 60 side (see FIG. 3), and a window 20W having a semicircular cross section is provided between the shielding portions 40M1, 40M2.

[0050] One end E2 of the foil electrode 30 faces the outer electrode 40, and the opposite end E1 faces the window 20W. The position of the window 20W relative to the outer surface 20S of the discharge tube 20 is determined so that only the end E2 of the foil electrode 30 faces the outer electrode 40.

[0051] Moreover, the window 20W is formed in a symmetrical region with the width direction (Y direction) of the foil electrode 30 as the axis of symmetry, and the window 20W is also formed in a symmetrical region with respect to the dielectric 50. Therefore, one end E2 of the foil electrode 30 faces the direction of the middle position of the semicircular cross-sectional portion 40M of the outer electrode 40, and the semicircular cross-sectional portion 40M is also formed in a symmetrical region with the width direction (Y direction) of the foil electrode 30 as the axis of symmetry.

[0052] In this manner, by arranging the foil electrode 30 in accordance with the formation position of the window 20W, in other words, by forming the window 20W taking into consideration the width direction (Y direction) of the foil electrode 30, the light radiation efficiency of the line irradiation type excimer lamp 10 is improved.

[0053] That is, the foil electrode 30 forms wedge shapes 34A, 34B that are sharpened toward both ends E1, E2 in the width direction, and one end E1 faces the outer electrode 40. Therefore, even if the area of ​​the window 20W, which is the emission surface (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.

[0054] Furthermore, because dielectric 50 is flattened along the width direction (Y direction) of foil electrode 30, its cross-sectional area is smaller than that of a dielectric having a circular cross section, ensuring the volume of discharge space S. In other words, the cross-sectional area of ​​discharge space S is large along the thickness direction (X direction) of foil electrode 30 when viewed from the window 20W side, which is the emission surface.

[0055] Therefore, while the light reflected by the outer electrode 40 is guided toward the window 20W, it is possible to suppress attenuation due to transmission through the dielectric 50. This makes it possible to configure a large-diameter excimer lamp 10 even though it is small, and it is possible to increase the illuminance by adjusting the diameter of the discharge tube 20 and the size of the window 20W.

[0056] Furthermore, the formation area of ​​window 20W is symmetrical with respect to the width direction (Y direction) of foil electrode 30 (line symmetry with respect to the Y direction as an axis), and the flattening direction of dielectric 50 is also along the width direction (Y direction) of foil electrode 30. This makes it possible to uniformize the illuminance distribution of light passing through window 20W.

[0057] As described above, the small diameter portion 53 of the dielectric 50 arranged inside the discharge tube 20 has a smaller diameter than the large diameter portion 55 outside the discharge space S. This makes it possible to ensure a larger volume of the discharge space S, and the light radiated from the discharge generated in the discharge space S is guided to the window 20W with reduced attenuation as it travels therethrough.

[0058] The wedge shapes 34A, 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 reducing the likelihood of peeling. Furthermore, by forming a flat portion 32 on the foil electrode 30, the adhesion between the foil electrode 30 and the dielectric 50 can be increased and peeling can be suppressed. As a result, the high level of light can be maintained while the lamp is lit.

[0059] Such a line irradiation type excimer lamp 10 can be manufactured, for example, by the following manufacturing method.

[0060] First, a power supply line is connected to the foil electrode by resistance welding or the like, and then inserted into a 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 fuse 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.

[0061] 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.

[0062] A brim-shaped, so-called bead-shaped sealing portion is formed at a position on the glass tube that corresponds to the edge of the electrode along the tube axis direction.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, and a dielectric with foil electrodes welded thereto is inserted into the discharge tube, and the insertion port of the discharge tube is welded to the bead-shaped sealing portion.

[0063] 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 area on the outer surface of the discharge tube that will become the window, which is the emission surface, is masked, and the area where the outer electrode is to be provided is surface-treated by irradiating it with ultraviolet light, and then it is formed directly on the outer surface of the discharge tube by sputtering. As shown in Figure 3, the discharge tube is covered with a film-like outer electrode such as an aluminum film that has the properties of reflecting light including ultraviolet light, and a window 20W with a semicircular cross section that will be the transparent portion for light including ultraviolet light is provided.

[0064] 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 part of the foil electrode 30 may be flat.

[0065] 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).

[0066] The thickness T2 of the foil electrode 30 can be determined according to the cross-sectional area, i.e., the inner diameter D1, of the discharge tube 20, 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 discharge tube 20.

[0067] Moreover, the width W of the foil electrode 30 can also be determined in accordance with the inner diameter D1 of the discharge tube 20, taking into consideration lighting startability due to electric field concentration, etc. For example, the width W of the foil electrode 30 can be determined to be ½ or less, preferably ¼ or less, of the inner diameter D1 of the emission surface 20D.

[0068] The outer electrode 40 may be configured with an electrode configuration other than an aluminum film, and light may not be reflected only by the outer electrode 40, but may be reflected by a material or member capable of reflecting light provided separately from the outer electrode 40. 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.

[0069] The size of window 20W, i.e., the ratio of the arc to the entire circumference (360°) of the outer surface of the discharge tube along the circumferential direction, may be determined according to the usage environment, etc., and a window having an arc-shaped cross section with a central angle of less than 180°, which is the central angle of the arc corresponding to half the circumference of the outer surface of the discharge tube, or a central angle of more than 180° may be formed in part of the circumferential direction of the outer surface of the discharge tube. In this case, window 20W may be formed so that both ends E1, E2 of foil electrode 30 face outer electrode 40. [Explanation of symbols]

[0070] 10 Excimer Lamp 20 discharge tube 30 foil electrode 40 Outer electrode 50 Dielectric

Claims

1. A discharge tube; a dielectric covering an inner electrode extending in a strip shape within the discharge tube; an outer electrode provided along a circumferential direction of an outer surface of the discharge tube; A line-emission type excimer lamp, wherein at least one end along the width direction of the inner electrode faces the outer electrode.

2. 2. The excimer lamp according to claim 1, wherein the other end along the width direction of said foil electrode faces the emission surface of said discharge tube.

3. 2. The excimer lamp according to claim 1, wherein the emission surface of the discharge tube is formed symmetrically with respect to the width direction of the inner electrode.

4. the inner electrode is disposed coaxially with respect to the dielectric; 2. The excimer lamp of claim 1, wherein the distance between the outer surface of the dielectric and the inner electrode along the thickness direction of the inner electrode is shorter than the distance between the outer surface of the dielectric and the inner electrode along the width direction of the inner electrode.

5. The inner electrode is a foil electrode, 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, 2. The excimer lamp according to claim 1, wherein the dielectric has a substantially constant thickness along the width direction of the foil electrode and an outer surface substantially parallel to the flat portion.

6. 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 of the dielectric body in the width direction and thickness direction of the inner electrode is smaller than the diameter of the large diameter portion.

7. 7. The excimer lamp according to claim 1, wherein the dielectric body is flat in shape to match the width direction of the inner electrode.

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

9. The inner electrode is a foil electrode, An excimer lamp as described in any one of claims 1 to 6, 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 in the width direction, and is sharpened from both ends of the flat portion toward both ends of the foil electrode in the width direction.

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