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

Abstract

To provide an excimer lamp that lights efficiently while improving the lighting start-up of the lamp.SOLUTION: An excimer lamp 10 includes an outer tube 20 and an inner tube 50 arranged coaxially in the outer tube 20. The inner tube 50 covers an inner electrode 30. A main discharge space S1 is formed between the outer tube 20 and the inner tube 50. A discharge space for lighting start-up assistance (hereinafter referred to as "auxiliary discharge space") S2 is formed between the inner electrode 30 and the inner tube 50.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

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

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

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

[0005] If a discharge space for start-up assistance is formed over the entire inner tube in order to irradiate the entire main discharge space with ultraviolet rays evenly, the input voltage in the normal (rated) lighting state is set to a voltage value that takes into account both the main discharge space and the discharge space for start-up assistance. This increases the voltage (power) required while the lamp is lit, affecting the lamp durability and lamp life.

[0006] Therefore, there is a demand for providing an excimer lamp that lights efficiently while improving the lamp's lighting startability. [Means for solving the problem]

[0007] The excimer lamp of the present invention comprises a dielectric covering foil electrodes arranged along the lamp axis direction, and a discharge vessel that is welded to the dielectric to form a main discharge space. The foil electrodes are partially sealed to the dielectric within the lamp axis direction range of the main discharge space, and are partially sealed so that an auxiliary discharge space is formed inside the dielectric. Here, "sealed" refers to welding the foil electrodes to the dielectric so as to be sealed (hermetically sealed).

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

[0009] For example, the foil electrode can be sealed to the dielectric in a region of low electric field strength along at least one of the lamp axial direction and the lamp circumferential direction of the foil electrode, and the auxiliary discharge space can be formed in a region of high electric field strength. The edge of the foil electrode can be spaced apart from the inner surface of the dielectric in the auxiliary discharge space.

[0010] Alternatively, the foil electrode may be sealed to the dielectric in a region of high electric field strength along at least one of the lamp axial direction and the lamp circumferential direction of the foil electrode, and the auxiliary discharge space may be formed in a region of low electric field strength. The edge of the foil electrode may be welded to the dielectric in the auxiliary discharge space.

[0011] The discharge vessel can be configured so that the tip position of the dielectric tip enters a small diameter portion provided at the tip of the discharge vessel, and the tip position of the foil electrode along the lamp axis is located rearward of the small diameter portion. Here, "entering the small diameter portion" means that the tip position of the tip is located closer to the bottom surface of the small diameter portion than the end of the small diameter portion closer to the lamp center along the vessel axial direction.

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

[0013] One aspect of the present invention is a method for lighting an excimer lamp, in an excimer lamp comprising an inner tube covering an inner electrode arranged along the lamp axial direction, and an outer tube welded to an enlarged diameter portion of the inner tube to form a main discharge space between the inner tube and the outer tube, wherein an auxiliary discharge space is formed between a surface of the inner electrode and an inner surface of the inner tube, and a portion of the light emitted from the auxiliary discharge space in the lamp axial direction is irradiated into the main discharge space through the tip portion on the opposite side to each diameter portion of the inner tube and the enlarged diameter portion.

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

[0015] According to the present invention, it is possible to provide an excimer lamp that lights efficiently while improving the lighting startability of the lamp. [Brief description of the drawings]

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

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

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

[0019] The excimer lamp 10 includes a discharge vessel 10T formed by an outer tube 20 and an inner tube 50, both made of a dielectric material such as quartz glass and having a substantially cylindrical cross section. A foil electrode (hereinafter referred to as the inner electrode) 30 extending in a strip shape having a width along the tube radial direction (hereinafter also referred to as the lamp radial direction) is covered by a columnar dielectric (hereinafter referred to as the inner tube) 50 along the tube axis (hereinafter also referred to as the lamp axis) C. The inner electrode 30 is not exposed to an annular discharge space (hereinafter referred to as the main discharge space) S1 formed between the outer tube 20 and the inner tube 50. The inner tube 50 here has a substantially circular cross section. The inner electrode 30 may be embedded in the inner tube 50.

[0020] The inner tube 50 is arranged coaxially with the outer tube 20. The inner electrode 30 is arranged coaxially with the outer tube 20 so that the center position in the width direction and thickness direction is aligned with the lamp axis C. The inner electrode 30 is arranged symmetrically with respect to the tube axis C. One end portion 20T2 of the outer tube 20 is heat-welded integrally with the expanded diameter portion 51 of the inner tube 50, thereby forming a discharge space (main discharge space) S1.

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

[0022] The discharge vessel 10T has protruding projections (hereinafter referred to as small diameter portions) 22, 52 at both ends of a constant inner diameter portion (hereinafter referred to as a cylindrical portion) 20T0 that surrounds the main discharge space S1. The small diameter portion 52 represents a portion of the rear end side of the inner tube 50 that extends along the lamp axis C beyond the end portion 20T2 of the outer tube 20 and has a small outer diameter that is not covered by the outer tube 20, and a power supply line 70 passes through the inside.

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

[0024] The end 50T1 of the inner tube 50 has a tip portion located in the spatial region of the small diameter portion 22, and the end 50T1 of the inner tube 50 contacts the small diameter portion 22. This allows the inner tube 50 to be stably held coaxially within the outer tube 20. The outer surface of the end 50T1 of the inner tube 50 has a tapered convex curved shape, and the inner surface of the small diameter portion 22 is formed into a tapered concave curved shape. This allows the inner tube 50 to be stably held coaxially without being damaged by dimensional errors caused by the hot forming of the inner tube 50 and the outer tube 20. While such a fitted state is formed, the position of the tip 30T1 of the inner electrode 30 along the lamp axis C is on the rear end side (the center of the discharge vessel) of the small diameter portion 22, without entering the internal space of the small diameter portion 22.

[0025] An electrode (hereinafter referred to as the outer electrode) 40 is disposed on the outer surface 20S of the outer tube 20. The outer electrode 40 is configured by winding a linear electrode portion made of a conductive metal along the surface of the outer tube 20, and is wound in a spiral shape along the tube axis C at predetermined intervals.

[0026] The axial arrangement range L of the outer electrode 40 is determined in a cylindrical portion 20T0 that is a constant inner diameter portion between the tapered ends 20T1, 20T2 of the outer tube 20. The axial length of the inner electrode 30 corresponds to the axial arrangement range L of the outer electrode 40. A power supply line 70 connected to an end of the inner electrode 30 is connected to an externally installed power supply unit (not shown), and power is supplied to the excimer lamp 10 via the power supply line 70.

[0027] Excimer light is emitted from the discharge space S1 by applying a high frequency (for example, in the range of several kHz to several tens of MHz) and a high voltage (for example, in the range of several kV to several tens of kV) to the inner electrode and the outer electrode. Here, ultraviolet light (for example, a wavelength of 172 nm) is emitted to the outside of the discharge vessel. Therefore, the excimer lamp 10 can be used in an ozone generator that generates ozone to sterilize, deodorize, etc., and can also be used in an ultraviolet irradiation device that directly irradiates an object with ultraviolet light.

[0028] A discharge space S2 for assisting in starting lighting (hereinafter referred to as auxiliary discharge space) is formed between the inner electrode 30 and the inner tube 50. As shown in Fig. 1, both axial ends 30T1, 30T2 of the inner electrode 30 are welded (sealed) to the inner tube 50 over their entire circumference. On the other hand, in the intermediate portion between both ends 30T1, 30T2 of the inner electrode 30, including the center in the lamp axial direction of the discharge vessel 10T, only both radial edges 30T3, 30T4 of the inner electrode 30 are welded to the inner tube 50. This forms the auxiliary discharge space S2.

[0029] Here, the range (auxiliary discharge space range) M of the auxiliary discharge space S2 along the lamp axis C is defined to be a portion shorter than the axial arrangement range of the inner electrode 30 corresponding to the axial arrangement range L of the outer electrode 40.

[0030] The auxiliary discharge space S2 is composed of two discharge space regions S2A and S2B surrounded by both side surfaces 30S1 and 30S2 (see FIG. 2) of the foil-like inner electrode 30 and the opposing inner surface of the inner tube 50. The cross-sectional shapes of the discharge space regions S2A and S2B are symmetrical with respect to the inner electrode 30 and the lamp axis C.

[0031] In addition, both edge portions 30T3, 30T4 of the foil-shaped inner electrode 30 have a knife-edge shape, and the inner electrode 30 becomes sharp from the center in the width direction toward the edge (end portion), and its thickness becomes thinner than the thickness at the center in the width direction, and both edge portions 30T3, 30T4 are pointed.

[0032] Therefore, in the lamp radial cross-sectional shape of the discharge space regions S2A, S2B, the length of the distance between the inner surface of the inner tube 50 and the surface of the inner electrode 30 along the thickness direction of the inner electrode 30 is longer near the center (lamp central axis) than the length T2 of the distance near both edges 30T3, 30T4 of the inner electrode 30, and is pointed toward both edges 30T3, 30T4 of the inner electrode 30.

[0033] Near both ends ST1, ST2 of the inner surface of the inner tube 50 exposed to the auxiliary discharge space S2 (both ends of the auxiliary discharge space range M), the distance between the inner electrode 30 and the inner tube 50 gradually decreases, the spatial region narrows, and the discharge space region points toward both ends 30T1, 30T2 of the inner electrode 30. The distance between the inner tube 50 and both side surfaces 30S1, 30S2 of the inner electrode 30 and the edges 30T3, 30T4 of the inner electrode 30 gradually decreases, and the inner tube 50 is sealed to the inner electrode 30.

[0034] That is, the auxiliary discharge space S2 (discharge space regions S2A, S2B) narrows and becomes sharp toward the ends 30T1, 30T2 in the longitudinal direction (lamp axis direction) along the surface of the foil-shaped inner electrode 30 and toward the edges 30T3, 30T4 in the width direction (lamp radial direction).

[0035] Both ends 30T1, 30T2 of the inner electrode 30 are in contact with and embedded in the inner tube 50 and are not exposed to the auxiliary discharge space S2. Moreover, both edge parts 30T3, 30T4 of the inner electrode 30 are in contact with and embedded in the inner tube 50 over a range M along the lamp axis direction of the auxiliary discharge space and are not exposed to the auxiliary discharge space S2. Therefore, the two discharge space regions S2A, S2B that constitute the auxiliary discharge space S2 are spatially separated by the inner electrode 30.

[0036] As described above, electric field concentration occurs near the edges 30T3 and 30T4 of the inner electrode 30 because the edges 30T3 and 30T4 have a knife-edge shape. Similarly, electric field concentration occurs near the ends 30T1 and 30T2 of the inner electrode 30. However, since each of them is embedded in the inner tube 50 and is not exposed to the auxiliary discharge space S2, wear of the inner electrode 30 due to discharge can be suppressed.

[0037] As described later, the auxiliary discharge space S2 is in a reduced pressure state lower than atmospheric pressure. It is also possible to fill the auxiliary discharge space S2 with a rare gas (lower than atmospheric pressure) that lowers the voltage at the start of lighting.

[0038] When a high-frequency high voltage is applied between the inner electrode 30 and the outer electrode 40, the auxiliary discharge space S2 is in a reduced pressure state, so that a discharge occurs first in the auxiliary discharge space S2 due to a lighting start voltage lower than that in the main discharge space S1. Then, part of the light (ultraviolet light in this case) emitted from the auxiliary discharge space S2 in the lamp radial direction is irradiated through the inner tube 50 to the main discharge space S1.

[0039] In addition, a portion of the light emitted in the lamp axial direction from the discharge generated in the auxiliary discharge space S2 is transmitted toward the ends 50T1 and 50T2 due to a fiber effect (an effect based on the same principle as optical fibers used in communication circuits) caused by repeated reflection within the tube wall of the inner tube 50 (at the boundary surface of the tube wall).

[0040] Here, part of the end 50T1 of the inner tube 50 enters and contacts the small diameter section 22, and since the expanded diameter section 51 is formed on the end 50T2 side of the inner tube 50, the ultraviolet light guided to the ends 50T1, 50T2 by the fiber effect is irradiated into the main discharge space S1 from both ends 20T1, 20T2 of the outer tube 20 through the end 50T1 and expanded diameter section 51 of the inner tube 50. This causes a discharge in the main discharge space S1.

[0041] The auxiliary discharge space S2 thus partially formed within the inner tube 50 improves the lighting startability. On the other hand, since the auxiliary discharge space S2 is sufficient as a minute discharge space area in which the radiated light reaches the main discharge space S1, it does not secure a space occupying most of the interior of the inner tube 50, and is formed as a partial discharge space area. Therefore, while the main discharge is generated and the lamp is lit, the voltage applied between the inner electrode 30 and the outer electrode 40 is suppressed, and the required power is reduced, thereby improving the lamp durability and lamp life.

[0042] The illuminance distribution (light distribution) along the outer peripheral surface of the discharge vessel varies depending on the shape of the discharge vessel and the position of the discharge generated inside it. Furthermore, the discharge state is affected by the electric field strength distribution determined by the positional relationship of the electrodes (anode and cathode) and the shapes of the covering tube, inner tube, and auxiliary discharge space. However, the above-mentioned excimer lamp 10 does not change the outer shape or discharge state of a conventional excimer lamp with a double-tube structure, so that it is possible to improve the lighting startability in an ultraviolet irradiation device or an ozone generator without affecting lamp characteristics such as discharge sustaining voltage and illuminance distribution or power supply characteristics suitable for them.

[0043] The lighting startability can be understood by the certainty (probability [%]) that a stable lighting state where a desired radiation spectrum is obtained from the discharge in the discharge vessel when a voltage is applied to the excimer lamp is reached. An excimer lamp is required to have certainty of lighting startability (100% reliability) even in low temperature conditions, in darkness, or after a long period of inactivity, but in this embodiment, a stable lighting state can be reliably reached without using a large lighting power supply or a light source for auxiliary lighting start, that is, lighting startability can be practically 100% certain.

[0044] The two discharge space regions S2A, S2B of the auxiliary discharge space S2, which are spatially separated from each other, are formed by embedding regions of high electric field strength near the edges 30T3, 30T4 and ends 30T1, 30T2 of the inner electrode 30 in the inner tube 50. Therefore, when a high-frequency high voltage is applied between the inner electrode 30 and the outer electrode 40, a discharge space is formed in the regions of low electric field strength in the lamp circumferential and axial directions.

[0045] However, because the auxiliary discharge space S2 is in a reduced pressure state, discharge is likely to occur with a lower lighting start voltage, and discharge occurs in the spatial region of the main discharge space S1 where the electric field strength is high, making it easier to transition to stable (rated) lighting. In this way, a stable lighting state can be achieved by generating an auxiliary discharge in the auxiliary discharge space where the electric field strength is low, and then transitioning to a main discharge in the main discharge space where the electric field strength is high.

[0046] On the other hand, the cross-sectional shape of the auxiliary discharge space S2 in the lamp radial direction is approximately uniform along the lamp axis C, and there is no bias in the electric field strength along the lamp axis C. Therefore, the ultraviolet light irradiated from the discharge vessel 10T to the outside of the lamp can have a uniform illuminance distribution along the lamp axial direction C.

[0047] The above-described excimer lamp 10 can be manufactured, for example, by the following manufacturing process.

[0048] A glass tube (inner tube) with a cylindrical cross section that serves as a covering for the foil electrode (inner electrode) is formed from a dielectric material that is transparent to the light emitted from the discharge formed in the auxiliary discharge space. After the inner tube is formed, a power supply wire is connected to the foil electrode by resistance welding or the like, and the foil electrode is inserted into the cylindrical glass tube with a bottom. After the foil electrode is inserted, the glass tube is reduced in pressure (vacuum) and sealed. At this time, a rare gas may be enclosed in the glass tube at atmospheric pressure or below.

[0049] The glass tube is heated while being rotated, and deformed so that it softens and shrinks (reduced in diameter). At this time, by bringing only the edge of the foil electrode along the width direction (tube diameter direction) into close contact with the inner surface of the glass tube, the heating (shrinkage) is stopped in a state where the edge of the foil electrode is embedded in the glass tube, and the edge of the foil electrode is not exposed, forming a space where the glass tube and the foil electrode are not in contact as an auxiliary discharge space.

[0050] In addition to forming the auxiliary discharge space, a brim-shaped (so-called abacus bead-shaped) enlarged diameter portion is formed at one end of the glass tube. Alternatively, the glass tube may not be rotated, and only the portion of the glass tube facing the edge of the foil electrode may be heated along the axial direction to adhere closely. The end of the foil electrode along the length direction (tube axis direction) is sealed in the entire circumferential direction, so that the end of the foil electrode is embedded in the glass tube and is not exposed to the auxiliary discharge space.

[0051] Regarding the outer tube, one end of a quartz tube that is transparent to the wavelengths of ultraviolet light emitted from the discharge formed in the main discharge space is reduced in diameter and an open introduction tube (tip tube) is provided, while the outer tube is formed with an open sealing portion with the expanded diameter portion of the inner tube.

[0052] The inner tube is then inserted into the outer tube so that they are coaxially arranged, and the sealed portion is heat-fused to form a discharge tube. After that, a vacuum is drawn through the introduction tube to remove impurities, and a discharge gas is sealed in the arc tube, and the introduction tube is heat-fused to hermetically seal it. Then, an outer electrode is disposed on the outer surface of the outer tube.

[0053] Next, an excimer lamp according to a second embodiment will be described with reference to Figures 3 and 4. In the second embodiment, an auxiliary discharge space is provided in the central portion of the lamp.

[0054] Fig. 3 is a schematic cross-sectional view of the excimer lamp according to the second embodiment as viewed from the side, and Fig. 4 is a schematic cross-sectional view of the excimer lamp according to the second embodiment as viewed from the axial direction.

[0055] In the second embodiment, the auxiliary discharge space S2 is formed in an auxiliary discharge space range M in the middle of the discharge vessel 10T, i.e., in the middle part including the center in the lamp axial direction. Therefore, parts of the edges 30T3, 30T4 of the inner electrode 30 are exposed to the auxiliary discharge space S2, and a spatial region with high electric field intensity is formed in the vicinity of the edges.

[0056] Near the center in the lamp axial direction, the entire circumference of the inner electrode 30 is exposed, and an auxiliary discharge space S2 is formed to surround it. Meanwhile, at both axial ends 30T1, 30T2 of the inner electrode 30, the entire circumference is sealed with the inner tube 50. Here, a range (auxiliary discharge space range) M of the auxiliary discharge space S2 along the lamp axis C is defined to be a partial section of the axial arrangement range of the inner electrode 30 corresponding to the axial arrangement range L of the outer electrode 40. Also, in the auxiliary discharge space range M, the outer diameter of the inner tube 50 is larger and the distance between the outer surface of the inner tube 50 and the inner surface of the outer tube 20 is smaller than in other ranges.

[0057] Near both ends ST1, ST2 of the inner surface of the inner tube 50 exposed to the auxiliary discharge space S2, the distance between the inner electrode 30 and the inner tube 50 gradually decreases, the spatial region narrows, and the discharge space region points toward both ends 50T1, 50T2 of the inner tube 50. The inner tube 50 is sealed to the inner electrode 30 while the distance between both side surfaces 30S1, 30S2 of the inner electrode 30 and the edges 30T3, 30T4 of the inner electrode 30 gradually decreases. The outer diameter of the inner tube 50 also gradually decreases, and the outer surface forms a smoothly curved surface.

[0058] Therefore, near both ends ST1, ST2 of the inner surface of the inner tube 50 exposed to the auxiliary discharge space S2, two discharge space regions are formed that are spatially blocked in the circumferential direction by the inner electrode 30, as in the first embodiment, but near the center of the auxiliary discharge space S2 (auxiliary discharge section M), a discharge space region that is connected in space is formed to surround the entire circumferential direction of the inner electrode 30.

[0059] 3, the spatial shape of the auxiliary discharge space S2 has a wider radial cross-sectional area closer to the center of the lamp (auxiliary discharge space range M) and a narrower spatial area closer to the small diameter parts 22, 52 at both ends of the discharge vessel 10T. Therefore, the distance L1 along the lamp radial direction between both edges 30T3, 30T4 of the inner electrode 30 in the central part along the lamp axis C of the auxiliary discharge space S2 and the inner circumferential surface of the inner tube 50 is longer than the distance L2 near both ends ST1, ST2 of the inner surface of the inner tube 50 exposed to the auxiliary discharge space S2.

[0060] 4, the auxiliary discharge space S2 has a wider radial cross-sectional area toward the center in the width direction (lamp radial direction) of the inner electrode 30. With regard to the length of the distance along the lamp radial direction between the inner surface of the inner tube 50 and the surface of the inner electrode 30, the length T1 along the thickness direction near the center (lamp central axis) is longer than the length T2 (corresponding to L1 in FIG. 3) along the width direction near both edges 30T3, 30T4 of the inner electrode 30.

[0061] That is, the auxiliary discharge space S2 is configured so that the spatial region narrows toward the ends 30T1, 30T2 in the length direction (lamp axial direction) of the foil-shaped inner electrode 30 and toward the edges 30T3, 30T4 in the width direction (lamp radial direction).

[0062] Most of the ends 30T1, 30T2 of the inner electrode 30 are in contact with the inner tube 50 while being embedded therein, and parts of the edges 30T3, 30T4 of the inner electrode 30 are exposed to the auxiliary discharge space S2, forming a spatial region with high electric field strength in the reduced pressure auxiliary discharge space S2, which makes it possible to generate discharge first in the auxiliary discharge space S2 with a lower lighting start voltage than in the main discharge space S1. Furthermore, it is possible to reduce the power required during lamp lighting and to suppress wear of the inner electrode 30 (particularly the edges) due to discharge.

[0063] On the other hand, the central portion of the auxiliary discharge space S2 is configured as a discharge space region surrounded by the inner surface of the inner tube 50 which covers the entire circumferential direction of the lamp axial direction in which both side surfaces 30S1, 30S2 of the inner electrode 30 are exposed, and in the vicinity of both ends ST1, ST2 of the inner surface of the inner tube 50 exposed to the auxiliary discharge space S2, opposing discharge space regions are formed with the inner electrode 30 in between as in the first embodiment, and the distance between the inner tube 50 and the inner electrode 30 is narrowed, so that the entire circumferential direction is finally sealed.

[0064] With this configuration, it is possible to radiate ultraviolet rays toward the entire discharge space S1, and a stable main discharge can be achieved in the discharge space S1. On the other hand, the auxiliary discharge space S2 is defined as a partial section of the axial arrangement range of the inner electrode 30 so that the electric field strength is approximately uniform along the lamp axis C. Therefore, the ultraviolet light irradiated from the discharge vessel 10T to the outside of the lamp can have a uniform illuminance distribution along the lamp axis C.

[0065] Furthermore, the spatial region of the auxiliary discharge space S2 changes asymptotically, i.e., the change in the inner shape of the inner tube 50 becomes smooth, improving the stability of the lamp intensity and other properties that are affected by stress concentration on the curved portions. Therefore, even when the inner tube 50 deteriorates (becomes embrittled) due to high-energy ultraviolet rays generated by the main discharge in the discharge space S1, damage to the discharge vessel 10T originating from the portion covering the auxiliary discharge space S2 can be prevented. Note that, as in the first embodiment, the inner surface of the inner tube 50 and the edge of the surface of the inner electrode 30 may be in contact with each other.

[0066] The above-mentioned excimer lamp 10 can be manufactured by the same manufacturing process as in the first embodiment. However, in the second embodiment, the inner tube into which the inner electrode is inserted and covered is heated and reduced in diameter so as to form the above-mentioned auxiliary discharge space S2 in the center of the inner tube, and the heating is stopped at a predetermined timing. For example, by not heating (reducing heating) the range in the lamp axial direction corresponding to the auxiliary discharge space range M, the reduction in diameter due to softening of the glass tube is suppressed (stopped) and the auxiliary discharge space is formed. The inner surface of the inner tube 50 and the surface (particularly the edge) of the inner electrode 30 may be in contact with each other.

[0067] Next, an excimer lamp according to a third embodiment will be described with reference to Figures 5 and 6. In the third embodiment, an auxiliary discharge space is formed at the end of the discharge vessel (inner tube).

[0068] Fig. 5 is a schematic cross-sectional view of the excimer lamp according to the third embodiment as viewed from the side, and Fig. 6 is a schematic cross-sectional view of the excimer lamp according to the third embodiment as viewed from the axial direction.

[0069] In the third embodiment, the auxiliary discharge space S2 is formed in an auxiliary discharge space range M at the tip of the discharge vessel 10T, i.e., near one end 50T1 of the inner tube 50 along the lamp axis C. Therefore, one end 30T1 (on the tip side) of the inner electrode 30 and parts of both edges 30T3, 30T4 (i.e., near the inner electrode part including the corners where both edges 30T3, 30T4 of the inner electrode 30 intersect with the end 30T1) are exposed to the auxiliary discharge space S2, and a spatial region with high electric field intensity is formed in the vicinity.

[0070] In addition, the end face 30E of the inner electrode 30 corresponds to the position where the distance between the inner surface of the end 50T1 of the inner tube 50 in the auxiliary discharge space S2 is maximum, and is configured so that a spatial region with high electric field strength is not formed on the end 50T1 side of the inner tube 50, even when a conductive member of the same potential (earth) as the outer electrode is placed near the end 50T1, thereby suppressing abnormal discharge near the end 20T1 of the outer tube 20.

[0071] For example, it is sufficient to set the distance between the tip (corner) of the end face 30E of the inner electrode 30 along the lamp axis C and the bottom of the inner surface of the inner tube 50 to be the maximum distance. On the other hand, the other (rear end) end 30T2 side including the center in the lamp axial direction of the inner electrode 30 is sealed to the inner tube 50 over its entire circumference.

[0072] Here, the range (auxiliary discharge space range) M of the auxiliary discharge space S2 along the lamp axis C includes a part of the axial arrangement range of the inner electrode 30 corresponding to the axial arrangement range L of the outer electrode 40, while extending toward the lamp tip side, and a part of it is determined to be a section that protrudes beyond the end 30T1 of the inner electrode 30. By configuring so that a spatial region with high electric field strength is not formed on the end 50T2 side of the inner tube 50, it is possible to suppress abnormal discharge near the end 20T2 of the outer tube 20. Furthermore, in the auxiliary discharge space range M, the outer diameter of the inner tube 50 is larger and the distance between the outer surface of the inner tube 50 and the inner surface of the outer tube 20 is smaller than in other ranges.

[0073] The auxiliary discharge space S2 is provided so as to protrude toward the small diameter portion 22, spanning from the spatial region where the outer electrode 40 and the inner electrode 30 face each other along the lamp radial direction to the spatial region where they do not face each other. The inner surface of the end portion 50T1 of the inner tube 50 which forms the auxiliary discharge space S2 has a tapered convex curved shape and forms a fitted state with the inner surface of the small diameter portion 22, while the position along the lamp axis C of the tip portion 30T1 of the inner electrode 30 is on the rear end side (the center of the discharge vessel) of the small diameter portion 22, without entering into the internal space of the small diameter portion 22.

[0074] 5, the spatial shape of the auxiliary discharge space S2 is such that the spatial area in the radial cross section is wider toward the center of the auxiliary discharge space S2 and narrows toward the small diameter parts 22, 52 at both ends of the discharge vessel 10T. Therefore, the distance L1 between both edges 30T3, 30T4 at the end face 30E of the inner electrode 30 and the inner surface of the inner tube 50 in the lamp radial direction of the inner electrode 30 is longer than the distance L2 at the end ST2 of the inner surface of the inner tube 50 exposed to the auxiliary discharge space S2. The outer diameter of the inner tube 50 also gradually decreases, and the outer surface forms a smoothly curved surface.

[0075] 6, the auxiliary discharge space S2 has a wider radial cross-sectional area toward the center in the width direction (lamp radial direction) of the inner electrode 30. Therefore, the length of the separation distance between the inner surface of the inner tube 50 and the surface of the inner electrode 30 along the lamp radial direction is such that the length T1 (corresponding to L1 in FIG. 5) of the separation distance along the thickness direction near the centers (lamp central axis) of both side surfaces 30S1, 30S2 of the inner electrode 30 is longer than the length T2 of the separation distance along the width direction near both edge portions 30T3, 30T4 of the inner electrode 30, and the length narrows toward both edge portions 30T3, 30T4 of the inner electrode 30.

[0076] The auxiliary discharge space S2 narrows in spatial area toward ends 30T1, 30T2 in the length direction (lamp axial direction) along the surface of the foil-like inner electrode 30 and toward edges 30T3, 30T4 in the width direction (lamp radial direction).

[0077] Most of the end 30T2 of the inner electrode 30 on the rear side including the center in the lamp axial direction is embedded in and in contact with the inner tube 50. The end 30T1 on the tip side of the inner electrode 30 and parts of the tip sides of both edges 30T3, 30T4, i.e., the vicinity of the tip of the inner electrode including the corners where both edges 30T3, 30T4 of the inner electrode 30 intersect with the end 30T1, are exposed to the auxiliary discharge space S2.

[0078] In the auxiliary discharge space S2, which is in a reduced pressure state, a spatial region with high electric field strength is formed near the end 20T1 at the tip side of the discharge vessel 20T, so that a discharge occurs in the auxiliary discharge space S2 before the main discharge space S1, making it possible to set a low lighting start-up voltage and preventing abnormal discharge on the end 20T1 side.

[0079] Moreover, since the auxiliary discharge space S2 is formed near the boundary of the axial arrangement range L of the outer electrode 40, power consumption is suppressed even during lamp lighting, and wear of the inner electrode 30 (particularly the corner at the tip) due to discharge can be suppressed. Note that, as in the first embodiment, the inner surface of the inner tube 50 and the surface of the inner electrode 30 (particularly the edge) may be in contact with each other.

[0080] On the other hand, as described above, most of the tip end ST1 of the auxiliary discharge space section S2, including the center in the lamp axial direction, is configured as a discharge space region surrounded by the inner surface of the inner tube 50 which covers the entire circumferential direction of the lamp axial direction in which both side surfaces 30S1, 30S2 of the inner electrode 30 are exposed, and near the rear end ST2 of the auxiliary discharge space section S2, the distance between the inner tube 50 and the inner electrode 30 is narrowed while forming opposing discharge space regions with the inner electrode 30 therebetween, as in the first embodiment, and the entire circumferential direction is finally sealed.

[0081] With this configuration, it is possible to radiate ultraviolet rays toward the entire discharge space S1, and a stable main discharge can be achieved in the discharge space S1. On the other hand, the auxiliary discharge space S2 is defined as a partial section of the axial arrangement range of the inner electrode 30 so that the electric field strength is approximately uniform along the lamp axis C. Therefore, the ultraviolet light irradiated from the discharge vessel 10T to the outside of the lamp can have a uniform illuminance distribution along the lamp axis C.

[0082] Furthermore, the spatial region of the auxiliary discharge space S2 changes asymptotically, i.e. the change in the inner shape of the inner tube 50 becomes smooth, improving the stability of the curved lamp intensity, etc. Therefore, even if the inner tube 50 deteriorates (becomes embrittled) due to high-energy ultraviolet rays generated by the main discharge in the discharge space S1, damage to the discharge vessel 10T originating from the part covering the auxiliary discharge space S2 can be prevented.

[0083] Such an excimer lamp 10 can be manufactured by the same manufacturing process as in the first and second embodiments. However, in the third embodiment, the inner tube covering the inner electrode is heated and reduced in diameter so that the above-mentioned auxiliary discharge space S2 is formed near the end 20T1 of the outer tube 20, and the heating is stopped at a predetermined timing. For example, by not heating (reducing heating) the range in the lamp axial direction corresponding to the auxiliary discharge space range M, the reduction in diameter due to softening of the glass tube is suppressed (stopped) and the auxiliary discharge space is formed. The inner surface of the inner tube 50 and the surface (particularly the edge) of the inner electrode 30 may be in contact with each other.

[0084] In the second and third embodiments, the auxiliary discharge space S2 is formed partially along the direction of the lamp axis C, but the auxiliary discharge space S2 may be formed to completely surround the inner electrode 30 in the circumferential direction in accordance with the axial arrangement range L of the outer electrode 40.

[0085] An excimer lamp according to a fourth embodiment will be described with reference to Figures 7 and 8. In the fourth embodiment, an auxiliary discharge space S2 is formed to surround the inner electrode 30 over the entire circumferential direction in accordance with the axial arrangement range L of the outer electrode 40.

[0086] Fig. 7 is a schematic cross-sectional view of the excimer lamp according to the fourth embodiment as viewed from the side, and Fig. 8 is a schematic cross-sectional view of the excimer lamp according to the fourth embodiment as viewed from the axial direction.

[0087] In the fourth embodiment, the auxiliary discharge space range M of the auxiliary discharge space S2 along the lamp axial direction is slightly shorter than the axial arrangement range L of the outer electrode 40. Therefore, similarly to the second embodiment, the inner electrode 30 is embedded in the inner tube 50 by being sealed in the entire circumferential direction near both ends 30T1, 30T2. In contrast, in the middle part including the center in the lamp axial direction of the inner electrode 30, the entire circumferential direction is exposed, and the auxiliary discharge space S2 is formed to surround it.

[0088] The range in which the auxiliary discharge space S2 is formed can be appropriately modified according to the lamp specifications, etc. For example, the axial range M of the auxiliary discharge space S2 can be set asymmetrically with respect to the center of the lamp. The inner surface of the inner tube 50 and the surface (particularly the edge) of the inner electrode 30 may be in contact with each other.

[0089] The above-mentioned excimer lamp 10 can be manufactured by the same manufacturing process as in the second embodiment. For example, by heating only the vicinity of both ends 30T1, 30T2 of the inner electrode 30 and not heating (reducing heating) the lamp axial direction range corresponding to the auxiliary discharge space range M, the diameter reduction caused by softening of the glass tube is suppressed (stopped) and the auxiliary discharge space is formed. The inner surface of the inner tube 50 and the surface (particularly the edge) of the inner electrode 30 may be in contact with each other, or the inner tube may be heated after the inner electrode is inserted to prevent the inner electrode from moving.

[0090] The outer electrodes may be embedded in the inner wall of the discharge tube so as to face each other, or one may be embedded and the other disposed on the outer surface of the discharge tube. The light emitted from the auxiliary discharge space is not limited to ultraviolet light, but may be visible light. [Explanation of symbols]

[0091] 10 Excimer Lamp 20 Outer tube 30 inner electrode 40 outer electrode 50 Inner tube (dielectric)

Claims

1. a dielectric covering the foil electrodes disposed along the lamp axial direction; a discharge vessel that is fused to the dielectric to form a main discharge space, the foil electrode has a cross-sectional shape along the lamp radial direction and extends in a strip shape along the lamp axial direction; 13. An excimer lamp comprising: a first electrode and a second electrode disposed in a first direction of said first electrode; a first electrode disposed in a first direction of said first electrode;

2. A dielectric covering a foil electrode arranged along the lamp axial direction; a discharge vessel that is fused to the dielectric to form a main discharge space, the foil electrode is partially sealed to the dielectric in a range of the main discharge space in the lamp axial direction so that an auxiliary discharge space is formed inside the dielectric; the foil electrodes are fused to the dielectric at at least one end of the foil electrodes in the longitudinal direction; 2. The excimer lamp according to claim 1, wherein the auxiliary discharge space is formed between the surface of the foil electrode and the inner surface of the dielectric so that the electric field strength varies along at least one of the lamp axial direction and the lamp circumferential direction.

3. 3. The excimer lamp of claim 2, wherein the foil electrode is sealed to the dielectric in an area of ​​low electric field strength along at least one of the lamp axial direction and the lamp circumferential direction of the foil electrode, and the auxiliary discharge space is formed in an area of ​​high electric field strength.

4. 3. The excimer lamp of claim 2, wherein the foil electrode is sealed to the dielectric in an area of ​​high electric field strength along at least one of the lamp axial direction and the lamp circumferential direction of the foil electrode, and the auxiliary discharge space is formed in an area of ​​low electric field strength.

5. 4. The excimer lamp according to claim 3, wherein an edge of said foil electrode is spaced apart from an inner surface of said dielectric body in said auxiliary discharge space.

6. 5. The excimer lamp according to claim 4, wherein an edge of said foil electrode is fused to said dielectric material in said auxiliary discharge space.

7. A dielectric covering a foil electrode arranged along the lamp axial direction; a discharge vessel that is fused to the dielectric to form a main discharge space, the foil electrode is partially sealed to the dielectric in a range of the main discharge space in the lamp axial direction so that an auxiliary discharge space is formed inside the dielectric; The tip position of the tip of the dielectric body enters into a small diameter portion provided at the tip of the discharge vessel, 2. An excimer lamp according to claim 1, wherein a tip end position of said foil electrode along the lamp axis is located rearward of said small diameter portion.

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

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

10. An excimer lamp includes an inner tube covering an inner electrode disposed along a lamp axis direction, and an outer tube fused to an expanded diameter portion of the inner tube to form a main discharge space between the inner tube and the outer tube, forming an auxiliary discharge space between a surface of the inner electrode and an inner surface of the inner tube; A method for operating an excimer lamp, comprising the steps of: irradiating a portion of the light emitted from the auxiliary discharge space in the lamp axial direction to the main discharge space through the tip of the inner tube on the main discharge space side and the expanded diameter portion.

11. inserting a foil-shaped inner electrode into a glass tube that will become an inner tube; a step of reducing the pressure inside the inner tube and sealing it, or sealing a rare gas in the inner tube at atmospheric pressure or lower; a step of heating the inner tube and reducing its diameter so as to form an auxiliary discharge space at least partially along the tube axis direction within the inner tube, thereby partially sealing the inner tube with the inner electrode; A method for manufacturing an excimer lamp, comprising:

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

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