JP2022182632A - Excimer lamp, method for lighting the same, and manufacturing method for the same - Google Patents

Abstract

To provide an excimer lamp capable of producing a desired discharge state in a main discharge space while improving the lighting start-up of the lamp.SOLUTION: An excimer lamp 10 includes an outer tube 20, a cladding tube 50' arranged coaxially in the outer tube 20 and covering a foil-shaped inner electrode 30, and an inner tube 60' covering the cladding tube 50'. An auxiliary discharge space S2 consisting of two relative discharge space areas S2A, S2B is formed between the cladding tube 50' and the inner tube 60'.SELECTED DRAWING: Figure 5

Description

The present invention relates to an excimer lamp, and more particularly to the construction of a discharge space.

Among excimer lamps, a double-tube structure lamp is known (see Patent Document 1). There, a dielectric covering a foil-shaped inner electrode is placed inside the discharge tube, and a voltage is applied between an outer electrode and an inner electrode provided on the outer surface of the discharge tube. As a result, excimer light such as ultraviolet rays is emitted from the discharge space formed between the dielectric and the discharge tube.

Also, an excimer lamp is known that has a start assist function that discharges at a voltage lower than the discharge start voltage in order to reliably light a high-output excimer lamp (see Patent Document 2). There, a discharge space for assisting starting filled with gas having a low starting voltage is formed in the inner tube of the double-tube structure lamp along the axial direction of the lamp. When the gas in the main discharge space is irradiated with the ultraviolet light emitted from the discharge space for starting assistance, discharge occurs in the main discharge space.

JP 2012-38658 A Japanese Patent Application Laid-Open No. 2017-4702

When the discharge space for assisting start-up is formed over the entire inner tube, ultraviolet rays of uniform intensity are emitted from the main discharge space to the outside of the lamp. However, in an ultraviolet irradiation device, an ozone generator, or the like equipped with an excimer lamp, a local discharge state is generated in the main discharge, and it may be required to suppress the intensity of ultraviolet rays (illuminance) and the concentration of generated ozone.

Therefore, it is required to provide an excimer lamp capable of generating a desired discharge state in the main discharge space while improving the lighting startability of the lamp.

An excimer lamp, which is one aspect of the present invention, comprises: a first dielectric covering foil-shaped electrodes arranged along the axial direction of the lamp; a second dielectric covering the first dielectric; and a discharge vessel forming a main discharge space. The first dielectric is partially welded to the second dielectric so that an auxiliary discharge space is formed between the first dielectric and the second dielectric in the lamp axial direction range of the main discharge space. is doing.

The first dielectric can be welded to the second dielectric at least at both longitudinal ends of the first dielectric, and the auxiliary discharge space extends along at least one of the lamp axial direction and the lamp circumferential direction. A dielectric field can be formed between the outer surface of the first dielectric and the inner surface of the second dielectric such that the electric field strength varies across the dielectric.

For example, the foil-shaped electrode is welded to the first dielectric and the second 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-shaped electrode, and the electric field strength is high. It is possible to form an auxiliary discharge space in the area. In this case, the auxiliary discharge space may be formed between the outer surface portion of the first dielectric and the inner surface of the second dielectric corresponding to the portion covering the edge of the foil electrode.

Alternatively, the first dielectric is welded to the second dielectric in a region of high electric field strength along at least one of the axial direction of the lamp and the circumferential direction of the foil electrode, and the auxiliary discharge space in a region of low electric field strength. It is possible to form In this case, the auxiliary discharge space can be formed between the outer surface of the first dielectric and the inner surface of the second dielectric according to the portion covering the side surface of the foil electrode.

The tip position of the tip portion of the first dielectric and/or the second dielectric enters the small diameter portion provided at the tip of the discharge vessel, and the tip position of the foil electrode along the lamp axis is the rear end of the small diameter portion. It can be configured to be on the side. Here, "entering the small diameter portion" means that the tip position of the tip portion is positioned closer to the bottom surface of the small diameter portion than the lamp central end portion of the small diameter portion along the container axis direction.

The auxiliary discharge space can be formed such that the distance between the first dielectric and the second dielectric along the width direction of the foil electrode is shorter at the edge than at the center. Also, the auxiliary discharge space is formed so that the distance between the first dielectric and the second dielectric along the length direction of the foil electrode is shorter at the end than at the center. can be done.

An excimer lamp lighting method, which is one aspect of the present invention, comprises an inner tube comprising a first dielectric covering an inner electrode arranged along the lamp axis direction and a second dielectric covering the first dielectric. , an excimer lamp comprising an outer tube welded to an enlarged diameter portion of an inner tube to form a main discharge space, wherein the outer surface of the first dielectric and the outer surface of the second dielectric are in the axial range of the main discharge space. An auxiliary discharge space is formed between the inner tube and the inner surface, and part of the light emitted from the auxiliary discharge space in the axial direction of the lamp is directed to the main discharge through the tip of the inner tube on the side of the main discharge space and the enlarged diameter portion. Irradiate space.

A method for manufacturing an excimer lamp, which is one aspect of the present invention, includes steps of inserting an inner electrode into a glass tube serving as a cladding tube or coating the inner electrode with a dielectric material serving as a cladding tube; a step of inserting a cladding tube into the inner tube, sealing the inside of the inner tube in a decompressed state, or enclosing a rare gas in the inner tube at a pressure below the atmospheric pressure, and a tube axial direction between the cladding tube and the inner tube. heating and reducing the diameter of the inner tube to partially weld the inner tube with the cladding tube so that an auxiliary discharge space is formed along the . For example, the main discharge space is formed by heat-welding the outer tube integrally with the enlarged diameter portion of the inner tube.

According to the present invention, it is possible to provide an excimer lamp capable of generating a desired discharge state in the main discharge space while improving the lighting startability of the lamp.

1 is a schematic cross-sectional view of an excimer lamp according to a first embodiment, viewed from the side; FIG. FIG. 2 is a schematic cross-sectional view of the excimer lamp of the first embodiment viewed from the axial direction; FIG. 10 is a schematic cross-sectional view of the foil electrode of the excimer lamp according to the second embodiment, viewed from the side along the width direction; FIG. 10 is a schematic cross-sectional view of the foil electrode of the excimer lamp according to the second embodiment, viewed from the side along the thickness direction; FIG. 2 is a schematic cross-sectional view of an excimer lamp according to a second embodiment, viewed from the side; FIG. 10 is a schematic cross-sectional view of the foil electrode of the excimer lamp according to the third embodiment, viewed from the side along the width direction; FIG. 11 is a schematic cross-sectional view of the foil electrode of the excimer lamp according to the third embodiment, viewed from the side along the thickness direction; FIG. 11 is a schematic cross-sectional view of an excimer lamp according to a third embodiment, viewed from the axial direction;

Embodiments of the present invention are described below with reference to the drawings.

FIG. 1 is a schematic cross-sectional view of the excimer lamp according to the first embodiment, viewed from the side. FIG. 2 is a schematic cross-sectional view of the excimer lamp of the first embodiment viewed from the axial direction side. FIG. 2 corresponds to a cross-sectional view along line BB in FIG. 1 corresponds to a cross-sectional view along a line passing through the central axis of the lamp in FIG.

The excimer lamp 10 includes an outer tube 20 having a substantially cylindrical cross section made of a dielectric material such as quartz glass, and a foil electrode (hereinafter referred to as A columnar (film-like) first dielectric (hereinafter referred to as a cladding tube) 50 covering the inner electrode 30 is coaxially arranged, and a cylindrical second dielectric (hereinafter referred to as a cladding tube) covering the cladding tube 50 is provided. A cladding tube 60, hereinafter referred to as an inner tube, is partially welded to the cladding tube 50 in the axial direction and extends along the lamp axis C. As shown in FIG.

The cladding tube 50 and the inner tube 60 are arranged coaxially with respect to the outer tube 20, and the inner electrode 30 is arranged coaxially with respect to the outer tube 20 so that its center position in the width direction and thickness direction is aligned with the lamp axis C. coaxially arranged. The inner electrode 30 is arranged symmetrically with respect to the tube axis C. As shown in FIG. One end portion 20T2 of the outer tube 20 is heat-welded integrally with the enlarged diameter portion 61 of the inner tube 60, thereby forming a discharge space (main discharge space) S1.

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

The discharge vessel 10T has projecting portions (hereinafter referred to as small diameter portions) 22, 62 at both ends of a constant inner diameter portion (hereinafter referred to as cylindrical portion) 20T0 surrounding the main discharge space S1. The small-diameter portion 62 is a portion of the rear end side of the inner tube 60 that is not covered with the outer tube 20 and protrudes along the lamp axis C toward the rear end of the lamp. A small-diameter portion 52 of the cladding tube 50 to be covered penetrates. It is also possible to cover the power supply line 70 with the small diameter portion 62 of the inner tube 60 so that the covering tube 50 is not exposed on the end side.

The small-diameter portion 22 is formed in the process of manufacturing the lamp, and protrudes from the discharge vessel 10T (outer tube 20) along the lamp axis C toward the tip of the lamp. Here, the distal end side of the outer tube 20 is deformed by heating to reduce its diameter, and a tip tube having a diameter smaller than that of the outer tube 20 is welded to form a partial section of the range of the discharge vessel 10T in the lamp axial direction, A small-diameter portion 22 having a smaller diameter than a range (axial arrangement range) L along the lamp axial direction in which the outer electrode 40 is arranged is integrally formed. Note that the tip tube used for manufacturing the lamp may be provided at a position different from the small diameter portion.

The end portion 50T1 of the cladding tube 50 enters the small diameter portion 22, the end portion 50T1 of the cladding tube 50 contacts the small diameter portion 22, and the cladding tube 50 is stably and coaxially held within the outer tube 20. Further, at the end portion 50T1 of the cladding tube 50, the outer surface is formed with a tapered convex curved surface, while the inner surface of the small-diameter portion 22 is formed with a tapered concave curved surface. As a result, the cladding tube 50 is stably and coaxially held with respect to the discharge vessel 10T so as not to be damaged due to dimensional errors due to heat molding.

It is also possible to adopt a configuration in which the tip end portion 60T1 of the bottomed cylindrical inner tube 60 that covers the end portion 50T1 of the cladding tube 50 from the tip side enters the small diameter portion 22 . While forming such a fitted state, the position of the tip portion 30T1 of the inner electrode 30 along the lamp axis C does not enter the internal space of the small diameter portion 22, and the rear end (discharge vessel) of the small diameter portion 22 center) side.

An electrode (hereinafter referred to as an outer electrode) 40 is arranged on the outer surface 20S of the outer tube 20 . The outer electrode 40 here has a configuration in which a linear electrode portion made of a conductive metal is wound along the surface of the outer tube 20, and is spirally arranged along the tube axis C at predetermined intervals. It is rolled up and placed.

The axial arrangement range L of the outer electrode 40 is defined in the tubular portion 20T0, which is a constant inner diameter portion between the tapered end portions 20T1 and 20T2 of the outer tube 20. As shown in FIG. The axial length of the inner electrode 30 here corresponds to the axial arrangement range L of the outer electrode 40 . A power supply line 70 connected to the end of the inner electrode 30 is connected to a power supply (not shown) installed outside, and power is supplied to the excimer lamp 10 via the power supply line 70 .

Excimer light is emitted from the discharge space S1 by applying high frequency (for example, several kHz to several tens of MHz) and high voltage (for example, several kV to ten and several kV) to the inner electrode and the outer electrode. . Here, ultraviolet light (eg, wavelength 172 nm) is radiated out of the discharge vessel. Therefore, the excimer lamp 10 can be applied to an ozone generator that performs sterilization and deodorization by generating ozone, and can also be applied to an ultraviolet irradiation apparatus that directly irradiates an object with ultraviolet rays. .

Between the cladding tube 50 and the inner tube 60, a discharge space (hereinafter referred to as an auxiliary discharge space) S2 for assisting lighting start-up is formed. As shown in FIGS. 1 and 2, the inner electrode 30 is sealed (closely attached) to the inner tube 60 over the entire lamp axis C direction and the entire circumference of the inner electrode 30 . The cladding tube 50 has a substantially elliptical cross-sectional shape, while the inner tube 60 has a substantially circular cross-sectional shape. An annular main discharge space S1 is formed between the inner tube 60 and the outer tube 20, and an auxiliary discharge space S2 is formed between the outer surface of the inner tube 60 and the inner surface of the inner tube 60. .

The auxiliary discharge space range (auxiliary discharge 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, near both ends 30T1 and 30T2 of the inner electrode 30, the outer peripheral surface of the cladding tube 50 and the inner peripheral surface of the inner tube 60 are sealed in the entire circumferential direction. On the other hand, in an intermediate portion including the center of the inner electrode 30 in the axial direction of the lamp, the entire outer peripheral surface of the inner tube 60 is exposed, and an auxiliary discharge space S2 is formed so as to surround it. Also, in the auxiliary discharge space range M, the outer diameter of the inner tube 60 is larger than in the other ranges, and the distance between the outer surface of the inner tube 60 and the inner surface of the outer tube 20 is small.

At both ends of the inner surface of the inner tube 60 exposed to the auxiliary discharge space S2 (both ends of the auxiliary discharge space range M) ST1 and ST2, the distance between the cladding tube 50 and the inner tube 60 gradually decreases, and the discharge space The space area narrows toward both ends 50T1 and 50T2 of the inner tube 60 . The inner tube 60 is welded to the cladding tube 50 while the distance between the inner surface of the inner tube 60 and the outer surface of the cladding tube 50 gradually decreases. The outer diameter of the inner tube 60 also gradually decreases, and the outer surface forms a smooth curved surface.

As shown in FIG. 1, the spatial shape of the auxiliary discharge space S2 is such that the radial cross-sectional area increases toward the center of the lamp (auxiliary discharge space range M), and increases toward the small-diameter portions 22 and 52 at both ends of the discharge vessel 10T. area is narrow. Therefore, the distance L1 along the lamp radial direction between the outer peripheral surface of the inner tube 60 and the inner peripheral surface of the inner tube 60 in the central portion of the auxiliary discharge space S2 along the lamp axis C is It is longer than the distance L2 at both ends ST1 and ST2 of the inner surface exposed to S2.

Both edge portions 30T3 and 30T4 of the foil-shaped inner electrode 30 are knife-edge shaped, and the inner electrode 30 is sharpened from the center in the width direction toward the edges (end portions), and its thickness is It is thinner than the thickness of the central portion, and both edge portions 30T3 and 30T4 are sharp. The radial cross section of the inner tube covering the foil-shaped inner electrode 30 is short in the thickness direction of the foil-shaped inner electrode 30 (minor axis direction), and the major axis direction is defined along the width direction.

Therefore, as shown in FIG. 3, the auxiliary discharge space S2 has a wider cross-sectional area in the radial direction toward the center in the width direction of the inner electrode 30 (radial direction of the lamp). Therefore, the length of the distance between the inner surface of the inner tube 60 and the outer surface of the inner tube 60 along the lamp radial direction is the distance along the width direction near both edges 30T3 and 30T4 of the inner electrode 30. The distance T1 along the thickness direction near the center (lamp center axis) is longer than the length T2 (corresponding to L1 in FIG. 1). , 30T4.

The auxiliary discharge space S2 is formed along the surface of the foil-shaped inner electrode 30 with respect to any of the ends 30T1 and 30T2 in the length direction (lamp axial direction) and the edge portions 30T3 and 30T4 in the width direction (lamp radial direction). Also, the discharge space area gradually becomes smaller and tapered.

Thus, the excimer lamp is provided with a three-layer structure discharge vessel 10T in which the main discharge space S1 and the auxiliary discharge space S2 are formed while the cladding tube 50 and the inner tube 60 are arranged coaxially with respect to the outer tube 20. By configuring 10, the auxiliary discharge space S2 can be formed without greatly changing the external shape of the conventional excimer lamp having a double tube structure. In addition, by using a film-like cladding tube, it is possible to make the outer shape equivalent to that of a conventional excimer lamp having a double-tube structure.

As described above, the edge portions 30T3 and 30T4 of the inner electrode 30 have a knife-edge shape, and electric field concentration occurs in the vicinity thereof. On the other hand, since the cladding tube 50 has an elliptical cross section, in the auxiliary discharge space S2, the electric field intensity differs in the circumferential direction during discharge, and the space regions where the electric field intensity is high are located near both edges 30T3 and 30T4 of the inner electrode 30. to form

However, since they are embedded in the cladding tube 50 and are not exposed in the auxiliary discharge space S2, wear of the inner electrode 30 due to discharge can be suppressed. In addition, it is possible to adjust the position of the inner electrode 30 relative to the inner tube 60, that is, the radial cross-sectional length direction during the manufacturing process. The cross-sectional shape of the cladding tube 50 can be circular, and the cross-sectional shape of the inner tube 60 can be elliptical.

The auxiliary discharge space S2 is in a pressure-reduced state lower than the atmospheric pressure, or is filled with a rare gas (below the atmospheric pressure) that lowers the voltage at the start of lighting. When a high-frequency high voltage is applied between the inner electrode 30 and the outer electrode 40, since the auxiliary discharge space S2 is in a decompressed state, the discharge starts in the auxiliary discharge space S2 first due to the lighting starting voltage lower than that in the main discharge space S1. occur. Part of the light (ultraviolet light in this case) emitted from the auxiliary discharge space S2 in the radial direction of the lamp is applied through the inner tube 60 to the main discharge space S1.

Part of the light emitted from the auxiliary discharge space S2 in the axial direction of the lamp is repeatedly reflected within the tube walls (boundary surfaces of the tube walls) of the cladding tube 50 and the inner tube 60, resulting in a fiber effect ( It is transmitted toward the ends 50T1, 50T2, 60T1 and 60T2 by the same principle as the optical fiber used in the communication circuit).

Here, part of the end portion 50T1 of the cladding tube 50 (the end portion 60T1 of the inner tube 60) enters the small-diameter portion 22 and comes into contact with the end portion 60T2 of the inner tube 60 (the end portion 50T2 of the cladding tube 50). is provided with an enlarged diameter portion 61 . Therefore, the ultraviolet rays guided by the fiber effect are irradiated into the main discharge space S1 from the both ends 20T1 and 20T2 of the outer tube 20 through the end 60T1 of the inner tube 60 (the end 50T1 of the cladding tube 50) and the enlarged diameter portion 61. be done. This causes a discharge in the main discharge space S1.

The auxiliary discharge space S2 partially formed in the inner tube 60 in this manner enhances the lighting startability. On the other hand, since the auxiliary discharge space S2 may be formed in a minute space area that generates a minute discharge enough for the radiated light to reach the main discharge space, a space that occupies most of the interior of the inner tube 60 is secured. It is formed as a partial discharge space area. Therefore, the voltage applied between the inner electrode 30 and the outer electrode 40 is suppressed while the lamp is lit, and the required electric power is suppressed, thereby increasing the lamp durability and lamp life.

Also, 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. Furthermore, the discharge state is affected by the electric field intensity distribution determined by the positional relationship of the electrodes (anode and cathode) and the shapes of the cladding tube, inner tube, and auxiliary discharge space. However, since the above-described excimer lamp 10 does not change the external shape and discharge state of the conventional double-tube structure excimer lamp, the lamp characteristics such as the discharge sustaining voltage and the illuminance distribution in the ultraviolet irradiation device and the ozone generator are not changed. Also, the lighting startability can be improved without affecting the power supply characteristics suitable for it.

The lighting startability can be grasped by the certainty (probability [%]) that a voltage is applied to the excimer lamp and the discharge in the discharge vessel reaches a stable lighting state in which a desired radiation spectrum is obtained. Excimer lamps require certainty (100% reliability) of lighting startability even after a low temperature state, a dark state, or after a long period of rest. A stable lighting state can be reliably achieved without using a lighting start assisting light source, that is, substantially 100% certainty of lighting start can be provided.

According to the above configuration, ultraviolet rays can be emitted toward the entire discharge space S1, and stable main discharge can be realized in the discharge space S1. On the other hand, the auxiliary discharge space S2 is defined in a partial section of the axial arrangement range of the inner electrode 30 so that the electric field intensity is substantially uniform along the lamp axis C. As shown in FIG. Therefore, the ultraviolet light emitted from the discharge vessel 10T to the outside of the lamp can have a uniform illuminance distribution in the axial direction C of the lamp.

In addition, the change in the spatial region of the auxiliary discharge space S2 is asymptotic, that is, the change in the shape of the inner surface of the inner tube 60 becomes smooth, and the curved surface portion (for example, the inner surface end portions ST1 where the inner tube 60 is exposed to the auxiliary discharge space S2 , ST2), the stability of the lamp intensity, etc. due to stress concentration is improved. Therefore, even when the inner tube 60 is degraded (embrittled) by high-energy ultraviolet rays generated by the main discharge in the discharge space S1, damage to the discharge vessel 10T starting from the portion covering the auxiliary discharge space S2 can be suppressed. can be done.

The excimer lamp 10 of the first embodiment can be manufactured, for example, as follows.

First, a glass tube (inner tube) having a cylindrical cross section is formed as a covering material for the foil-shaped inner electrode. After forming the inner tube, a power supply line is connected to the inner electrode by resistance welding or the like, and the inner electrode is inserted into the bottomed cylindrical inner tube. After inserting the inner electrode, the tube is decompressed (vacuum) and sealed.

The inner tube is heated while being rotated, and deformed so that the glass tube softens and shrinks (diameter reduction). At this time, the inner electrode is brought into close contact with the glass tube over the entire circumferential direction and the entire axial direction. Also, the diameter is reduced so as to have an elliptical cross section. At least the surface of the inner electrode in the auxiliary discharge space range M may be coated with a dielectric as a cladding tube.

Thereafter, a cladding tube covering the inner electrode is formed from a dielectric material having transparency to light emitted from the discharge formed in the auxiliary discharge space, and a glass tube (inner tube) covering the cladding tube is formed. do. After molding the cladding tube and the inner tube, the cladding tube is inserted into the inner tube and heated to reduce the diameter.

At this time, heating is performed to partially weld the inner tube along the axial direction of the lamp so as to form an auxiliary discharge space. Along with the formation of the auxiliary discharge space, a brim-shaped (so-called abacus bead-shaped) sealing portion is formed at one end of the inner tube. Alternatively, the inner tube may not be rotated, and only the inner peripheral surface of the inner tube and the edge of the foil electrode may be heated to bring them into close contact with each other.

As for the outer tube, an introduction tube (tip tube) is provided, which is made by reducing the diameter of one end of a quartz tube that is transparent to the wavelength of ultraviolet rays emitted from the discharge formed in the main discharge space and is open. An outer tube is formed with an open seal. Then, the inner tube is inserted into the outer tube so that they are coaxially arranged, and they are heat-welded at the sealing portion to form the discharge tube. After that, the introduction tube is evacuated to remove impurities, the arc tube is filled with discharge gas, and the introduction tube is hermetically sealed by heating and melting. An outer electrode is then disposed on the outer surface of the outer tube.

Next, an excimer lamp of a second embodiment will be described with reference to FIGS. 3 to 5. FIG. In the second embodiment, the cladding tube and the inner tube are partially welded along the circumferential direction so as to cover the side surface of the foil electrode, thereby forming an auxiliary discharge space in a range facing the edge of the foil electrode. and an auxiliary discharge space is formed between the cladding tube and the inner tube along the lamp axial direction.

FIG. 3 is a schematic cross-sectional view of the foil electrode of the excimer lamp according to the second embodiment, viewed from the side along the width direction. FIG. 4 is a schematic cross-sectional view of the foil electrode of the excimer lamp according to the second embodiment, viewed from the side along the width direction. FIG. 5 corresponds to a cross-sectional view along line BB in FIG. 5 corresponds to a cross-sectional view taken along a line passing through the central axis of the lamp in FIG.

As shown in FIG. 5, the cladding tube 50' has a circular cross section in the lamp radial direction after being sealed with the foil-shaped inner electrode 30. As shown in FIG. On the other hand, the inner tube 60' has an elliptical cross section in the lamp radial direction after being welded to the cladding tube 50'. In the lamp radial cross section, the inner surface portion 60′K2 along the minor axis direction (the thickness direction of the inner electrode 30) of the inner tube 60′ is the outer surface of the cladding tube 50′ that covers the side surfaces 30S1 and 30S2 of the inner electrode 30. Weld with parts.

As a result, between the inner surface portion 60′K1 along the longitudinal direction of the inner tube 60′ (the width direction of the inner electrode 30) and the outer surface portion of the cladding tube 50′ covering the edges 30T3 and 30T4 of the inner electrode 30 , there is formed an auxiliary discharge space S2 composed of discharge space regions S2A and S2B separated by two spaces.

Within the inner tube 60', the two discharge space regions S2A, S2B are spatially separated by the cladding tube 50'. Further, in the second embodiment, unlike the first embodiment, the cross-sectional shape of the inner tube 60' is elliptical, while the cross-sectional shape of the cladding tube 50' is circular.

The discharge space regions S2A and S2B are opposed to each other in the width direction of the inner electrode 30 and are symmetrical with respect to the cross section in the radial direction. The axial section (auxiliary discharge section) M of the auxiliary discharge space S2 has a length along the lamp axis C slightly shorter than the axially disposed section L of the outer electrode 40 . Therefore, near both ends 30T1 and 30T2 of the inner electrode 30, the outer peripheral surface of the cladding tube 50' and the inner peripheral surface of the inner tube 60' are sealed in the entire circumferential direction. In addition, in the auxiliary discharge space range M, the outer diameter of the inner tube 60' is larger than in the other ranges, and the distance between the outer surface of the inner tube 60' and the inner surface of the outer tube 20 is small.

On the other hand, in an intermediate portion between both ends 30T1 and 30T2 of the inner electrode 30 and including the center of the inner electrode 30 in the axial direction of the lamp, only the portion covering both side surfaces 30S1 and 30S2 of the inner electrode 30 is covered with the cladding tube 50'. The inner tube 60' is partially welded along the circumferential direction. As a result, an auxiliary discharge space S2 (S2A, S2B) is formed in the space portion in the direction in which both edges 30T3, 30T4 of the inner electrode 30 face.

In the discharge space regions SAT1, SAT2, SBT1, and SBT2 at both ends of the auxiliary discharge space S2, the distance between the cladding tube 50' and the inner tube 60' is gradually shortened as in the first embodiment. is narrowed toward both ends 50T1 and 50T2 of the cladding tube 50'. The inner tube 60' is sealed to the cladding tube 50' while the distance between the inner surface of the inner tube 60' and the outer surface of the cladding tube 50' is gradually reduced. The outer diameter of the inner tube 60' also gradually decreases, and the outer surface forms a smooth curved surface.

As shown in FIG. 4, the spatial shape of the auxiliary discharge space S2 is such that the radial cross-sectional area becomes wider toward the center of the lamp (auxiliary discharge space range M), and the discharge space areas SAT1, SAT2, SBT1 at both ends of the auxiliary discharge space S2. , SBT2, the spatial region narrows. Therefore, the distance L1 along the radial direction of the lamp between the outer peripheral surface of the cladding tube 50' and the inner peripheral surface of the inner tube 60' in the central portion of the auxiliary discharge space S2 along the lamp axis C is It is longer than the distance L2 between the discharge space regions SAT1 (SBT1) and SAT2 (SBT2) at both ends.

Therefore, in the lamp radial cross-sectional shape of the discharge space regions S2A and S2B, the distance between the inner surface of the inner tube 60′ and the outer surface of the cladding tube 50′ along the lamp radial direction is the length of the inner electrode 30. The length T1 of the separation distance in the thickness direction (side surfaces 30S1, 30S2) of the inner electrode 30 is shorter than the length T2 of the separation distance along the width direction (edges 30T3, 30T4). tapered along the

The auxiliary discharge space S2 (discharge space regions S2A and S2B) is formed between the inner electrode 30 and the outer electrode 40 by a configuration in which the discharge space region is gradually reduced and tapered in both the lamp radial direction and the lamp circumferential direction. When a high frequency high voltage is applied to , a space region with a high electric field strength is formed in the width direction of the inner electrode 30 (near both edges 30T3 and 30T4) in the reduced pressure auxiliary discharge space S2. As a result, discharge occurs first in the auxiliary discharge space S2 at a lighting starting voltage lower than that in the main discharge space S1, and discharge occurs in the space region where the electric field intensity is high in the main discharge space S1, thereby shifting to stable (rated) lighting. easier.

Also, the electric field strength in the main discharge space S1 differs in the lamp circumferential direction and is substantially equal in the lamp axial direction. As a result, local discharge is likely to occur also in the main discharge space S1, and the ultraviolet rays are radiated so that the intensity of the ultraviolet rays (illuminance distribution) is uneven along the circumferential direction of the lamp and uniform in the axial direction C of the lamp. be. Therefore, it is possible to irradiate ultraviolet rays and generate ozone in accordance with the usage environment of the ultraviolet irradiation device and the ozone generator.

The cladding tube 50 is partially welded to the inner tube 60 in the circumferential direction to form the auxiliary discharge space S2. changes smoothly, and the stability of the lamp intensity, etc. due to stress concentration on the curved surface portion is improved. Therefore, even when the cladding tube 50' and the inner tube 60' are degraded (embrittled) by the high-energy ultraviolet rays generated by the main discharge in the discharge space S1, the discharge vessel 10T starting from the portion covering the auxiliary discharge space S2 can be discharged. damage can be suppressed.

The excimer lamp of the second embodiment can be manufactured as follows. First, as in the first embodiment, the inner electrode is inserted into the glass tube serving as the cladding tube and heated to reduce the diameter of the glass tube. At this time, the inner electrode is brought into close contact with the glass tube over the entire circumferential direction and the entire axial direction. Also, the diameter is reduced so as to have a circular cross section. Note that the surface of the inner electrode may be coated with a dielectric. After that, the coated tube coated with the inner electrode is inserted into the inner tube, which is a glass tube, and heated to reduce the diameter. At this time, heating and diameter reduction are performed to weld a portion of the inner tube in the circumferential direction to the cladding tube along the direction of the lamp axis C so as to form two discharge space regions S1 and S2. Other configurations are the same as the steps of the first embodiment.

Next, an excimer lamp according to a third embodiment will be described with reference to FIGS. 6 to 8. FIG. In the third embodiment, the cladding tube and the inner tube are partially welded along the circumferential direction so as to cover the edge of the foil electrode, thereby forming an auxiliary discharge space in a range facing the side surface of the foil electrode. and an auxiliary discharge space is formed between the cladding tube and the inner tube along the lamp axial direction.

FIG. 6 is a schematic cross-sectional view of the foil electrode of the excimer lamp according to the third embodiment, viewed from the side along the width direction. FIG. 7 is a schematic cross-sectional view of the foil electrode of the excimer lamp of the third embodiment, viewed from the side along the thickness direction. FIG. 8 is a schematic cross-sectional view of the excimer lamp of the third embodiment as seen from the axial direction side.

As shown in FIG. 8, in the excimer lamp 10 of the third embodiment, the cladding tube 50″ has an elliptical lamp radial cross section. , are formed in a circle. In the cross section in the radial direction of the lamp, the inner surface portion of the inner tube 60″ covering the edge portions 30T3 and 30T4 sides of the inner electrode 30 is the outer surface portion along the longitudinal direction of the cladding tube 50″ (the width direction of the inner electrode 30). It is welded with 50″K1.

Then, a spatial These two spatial regions are used as auxiliary discharge spaces S2A and S2B to form an auxiliary discharge space S2.

As in the second embodiment, the two discharge space regions S2A and S2B are spatially isolated by the cladding tube 50'', but in the third embodiment, the cross-sectional shape of the inner tube 60'' is circular. On the other hand, the cladding tube 50″ has an elliptical cross-sectional shape. The discharge space regions S2A and S2B are opposed to each other in the thickness direction of the inner electrode 30 and are symmetrical with respect to the cross section in the radial direction. be.

In the lamp radial cross-sectional shape of the discharge space regions S2A and S2B, the length of the distance between the inner surface of the inner tube 60″ and the outer surface of the cladding tube 50″ along the lamp radial direction is the width direction of the inner electrode 30. The distance T1 in the thickness direction (side surfaces 30S1, 30S2) of the inner electrode 30 is longer than the distance T2 along the edges (edges 30T3, 30T4). , the discharge space regions S2A and S2B are tapered.

With such a configuration, when a high-frequency high voltage is applied between the inner electrode 30 and the outer electrode 40, discharge occurs first in the auxiliary discharge space S2, which is in a decompressed state, at a lighting starting voltage lower than that in the main discharge space S1. , correspondingly, a discharge is generated in the space region where the electric field intensity is high in the main discharge space S1, and it is possible to shift to stable (rated) lighting.

Thus, according to the third embodiment, regardless of the cross-sectional length direction (stretching direction) of the foil-shaped inner electrode 30, the two discharge space regions S2A and S2B in the inner tube 60″ are separated from each other by the cladding tube. By adjusting the shape of the inner tube and the welded portion along the circumferential direction, it is possible to form it at a desired position.

The excimer lamp 10 described above can be manufactured by a manufacturing process similar to that of the second embodiment.

The axial section M of the auxiliary discharge space S2 is configured to match the axial section L of the outer electrode 40. However, if the auxiliary discharge space S2 is formed at the center or end of the lamp, the direction of the lamp axis C may be changed. may be partially formed between the inner tube 60 and the cladding tube 50 along the .

As for the outer electrodes, they may be embedded in the inner wall of the discharge tube so as to face each other, or one of them may be embedded and the other may be arranged on the outer surface of the discharge tube. Moreover, the light emitted from the auxiliary discharge space is not limited to ultraviolet light, and may be visible light.

REFERENCE SIGNS LIST 10 excimer lamp 20 outer tube 30 inner electrode 40 outer electrode 50 cladding tube (dielectric)
60 inner tube (dielectric)

Claims (12)

a first dielectric covering the foil electrodes arranged along the lamp axis;
a second dielectric covering the first dielectric;
a discharge vessel welded to the second dielectric to form a main discharge space;
In the lamp axial range of the main discharge space, the first dielectric and the second dielectric are partially spaced apart so that an auxiliary discharge space is formed between the first dielectric and the second dielectric. An excimer lamp characterized by being welded together. the first dielectric is welded to the second dielectric at at least one longitudinal end of the first dielectric;
The auxiliary discharge space is formed between the outer surface of the first dielectric and the inner surface of the second dielectric such that the electric field intensity varies along at least one of the lamp axial direction and the lamp circumferential direction. 2. An excimer lamp according to claim 1, characterized in that: The foil electrode is welded to the first dielectric and the second 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 electric field strength is increased. 3. An excimer lamp according to claim 2, wherein said auxiliary discharge space is formed in a region of high . The first dielectric is welded to the second 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 dielectric in a region of low electric field strength. 3. The excimer lamp of claim 2, wherein a discharge space is formed. The auxiliary discharge space is formed between the outer surface portion of the first dielectric and the inner surface of the second dielectric corresponding to the portion covering the edge of the foil electrode. An excimer lamp according to claim 3. 3. The auxiliary discharge space is formed between the outer surface of the first dielectric and the inner surface of the second dielectric corresponding to the portion covering the side surface of the foil electrode. 6. The excimer lamp according to any one of 2 to 5. a tip position of the tip portion of the first dielectric and/or the second dielectric enters the small diameter portion provided at the tip of the discharge vessel;
7. The excimer lamp according to claim 1, wherein the tip position of the foil electrode along the lamp axis is located on the rear end side of the small diameter portion. The auxiliary discharge space is formed such that the distance between the first dielectric and the second dielectric along the width direction of the foil electrode is shorter at the edge than at the center. 8. An excimer lamp according to any one of claims 1 to 7, characterized in that: The auxiliary discharge space is formed such that the distance between the first dielectric and the second dielectric along the length direction of the foil electrode is shorter at the end than at the center. 9. An excimer lamp according to any one of claims 1 to 8, characterized in that: an inner tube composed of a first dielectric covering an inner electrode disposed along the lamp axial direction and a second dielectric covering the first dielectric; An excimer lamp comprising an outer tube forming a discharge space,
forming an auxiliary discharge space between the outer surface of the first dielectric and the inner surface of the second dielectric in the lamp axial range of the main discharge space;
A part of the light emitted from the auxiliary discharge space in the axial direction of the lamp is irradiated to the main discharge space through the tip portion of the inner tube on the side of the main discharge space and the enlarged diameter portion. How to light an excimer lamp. a step of inserting an inner electrode into a glass tube that serves as a cladding tube, or coating the inner electrode with a dielectric that serves as a cladding tube;
a step of inserting the cladding tube into a glass tube serving as an inner tube;
a step of sealing the inside of the inner tube under reduced pressure, or enclosing a noble gas in the inner tube at a pressure below atmospheric pressure;
a step of heating and reducing the diameter of the inner tube to partially weld the inner tube and the cladding tube so that an auxiliary discharge space is formed between the cladding tube and the inner tube along the axial direction of the tube; A method for manufacturing an excimer lamp, comprising: 12. The method of manufacturing an excimer lamp according to claim 11, wherein the main discharge space is formed by heat-welding the discharge vessel integrally with the enlarged diameter portion of the inner tube.

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