Excimer lamp and ultraviolet irradiation device

Abstract

A channel is formed that can effectively irradiate ultraviolet light using an excimer lamp. [Solution] The excimer lamp of the ultraviolet irradiation device is formed by welding a discharge container 20 and a processing container 30 together, and a flow path R, which is a processing space, is formed around the discharge container 20. The distance G2 between the outer surface 20S of the discharge container 20 and the inner surface 30S of the processing container 30 in the flow path R is determined such that the ultraviolet intensity ratio of ultraviolet light that passes through the outer surface 30M of the processing container 30 is 30% or less.

Description

Technical Field

[0001] The present invention relates to an excimer lamp and an ultraviolet irradiation device.

Background Art

[0002] In an excimer lamp, discharge light emission is caused by applying a high-frequency voltage between electrodes, and the ultraviolet rays radiated from the discharge vessel can be irradiated onto an object to be irradiated or the like. Also, ozone can be generated by irradiating an ozone-generating source gas with ultraviolet rays.

[0003] In the case of vacuum ultraviolet rays having a peak wavelength in the wavelength range of 200 nm or less, which are easily absorbed by oxygen molecules, the ultraviolet rays are attenuated after traveling a relatively short distance, and the ultraviolet ray intensity decreases. Therefore, a spatial region with insufficient ultraviolet ray intensity occurs in the flow path through which a raw material gas or the like flows.

[0004] In order to effectively irradiate a gas, a liquid, or the like to be irradiated with ultraviolet rays, an excimer lamp having a flow path provided between an outer tube and an inner tube is known (see Patent Document 1). In that case, the inner tube and the outer tube are partially welded, and a flow path is formed in the non-welded portion (see Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the case of excimer lamps, it is necessary to determine the distance between the flow channel (hereinafter referred to as the processing vessel) and the discharge vessel while considering the attenuation characteristics of ultraviolet light. For example, in the case of ultraviolet light with a wavelength of 172 nm, ultraviolet light is significantly attenuated over short transmission distances, so if the distance between the flow channels is too large, the proportion of fluid flowing in areas with low ultraviolet irradiance will be greater than the proportion of fluid flowing in areas with high ultraviolet irradiance.

[0007] In particular, in the case of an excimer lamp with a lamp structure in which a pair of electrodes are arranged on either side of a discharge space and a flow path, if the ratio of the distance between the flow paths to the distance between the discharge spaces is large, the applied voltage contributing to the discharge in the discharge space will decrease, which may reduce the illuminance of ultraviolet light irradiating the flow path. In addition, the inner diameter of the processing container will become larger relative to the outer diameter of the discharge container, which hinders the thinning of the processing container and thus the miniaturization of the excimer lamp. For this reason, it is necessary to shorten the distance between the flow paths.

[0008] On the other hand, if the distance between flow channels is too small, the fluid will flow through areas with high UV intensity, and the treatment container will also be located in an area with high UV intensity. As a result, the treatment container will be continuously exposed to high-intensity UV light, accelerating its deterioration. This could lead to the treatment container being damaged due to fluid pressure fluctuations before the lamp reaches the lifespan of the discharge vessel. Furthermore, UV light is absorbed and attenuated by the treatment container located in an area with high UV intensity, reducing the UV treatment efficiency. An inappropriate UV intensity relative to the distance between flow channels reduces both the efficiency and reliability of the UV treatment.

[0009] Therefore, it is necessary to create a flow path that can effectively irradiate the fluid to be irradiated with ultraviolet light and suppress the deterioration of the processing container. [Means for solving the problem]

[0010] An excimer lamp according to one aspect of the present invention comprises a discharge vessel that forms a discharge space, and a processing vessel that covers the discharge vessel and forms a processing space between it and the discharge vessel that serves as a flow path for a fluid to be irradiated with ultraviolet light, wherein the distance between the outer surface of the discharge vessel and the inner surface of the processing vessel is determined such that when excimer light having a peak wavelength of 172 nm is transmitted through the outer surface of the processing vessel by discharge, the ultraviolet intensity is 30% or less.

[0011] Ultraviolet light is emitted from the discharge space by an electrical discharge, and its configuration varies. For example, an excimer lamp that emits ultraviolet light can be used as the light source. The form of the processing container and its arrangement relative to the discharge container also vary. For example, the processing container can be welded to the discharge container and integrated with it so as to form the flow path between the discharge container and the processing container.

[0012] In the case of an excimer lamp (especially a small excimer lamp), for example, the thickness T1 of the discharge container, the thickness T2 of the processing container, and the distance G2 between the outer surface of the discharge container and the inner surface of the processing container can be determined to be within the following ranges. 0.7 ≤ T1(mm) ≤ 2 0.5 ≤ T2(mm) ≤ 3 0.2 ≤ G2(mm) ≤ 6

[0013] The ultraviolet irradiation device can be applied to processes such as organic matter decomposition, sterilization, and ozone generation. When irradiating gases or liquids containing oxygen, such as for ozone generation, the distance between the outer surface of the discharge container and the inner surface of the processing container can be set to a distance that allows for expected absorption of ultraviolet light by oxygen. For example, the distance between the outer surface of the discharge container and the inner surface of the processing container can be set such that the ultraviolet intensity distribution when the excimer light passes through the outer surface of the processing container has a maximum at wavelengths longer than 172 nm.

[0014] The distance between the outer surface of the discharge container and the inner surface of the processing container is such that the irradiance when the excimer light passes through the outer surface of the processing container is 2 mW / cm². 2 The following can be determined: Alternatively, the irradiance of the excimer light on the outer surface of the discharge vessel may be 4 mW / cm². 2 The above may be the case. Alternatively, the distance between the outer surface of the discharge container and the inner surface of the processing container and the thickness of the processing container may be such that the irradiance of the excimer light on the outer surface of the processing container is 2 mW / cm². 2 It can be determined as follows:

[0015] Another embodiment of the present invention is an excimer lamp comprising a tubular discharge vessel and a tubular processing vessel surrounding the discharge vessel and forming a flow path between them, wherein the distance between the outer surface of the discharge vessel and the inner surface of the processing vessel is determined such that when excimer light having a peak wavelength of 172 nm is transmitted through the outer surface of the processing vessel by discharge, the ultraviolet intensity is 30% or less.

[0016] Another aspect of the present invention is an ultraviolet irradiation method using an ultraviolet irradiation apparatus comprising a discharge vessel that forms a discharge space, and a processing vessel that covers the discharge vessel and forms a processing space between it and the discharge vessel that serves as a flow path for a fluid to be irradiated with ultraviolet light, wherein the distance between the outer surface of the discharge vessel and the inner surface of the processing vessel is determined such that when excimer light having a peak wavelength of 172 nm is transmitted through the outer surface of the processing vessel by discharge, the ultraviolet intensity is 30% or less, and ultraviolet light is emitted from the discharge space by discharge. [Effects of the Invention]

[0017] According to the present invention, it is possible to effectively irradiate a fluid that is to be irradiated with ultraviolet light and to form a flow path that can suppress the deterioration of the processing container. [Brief explanation of the drawing]

[0018] [Figure 1]It is a cross-sectional view along the lamp axis of the excimer lamp of the ultraviolet irradiation device according to the first embodiment. [Figure 2] It is a cross-sectional view taken along line II-II of FIG. 1. [Figure 3] It is a partially enlarged view showing the vicinity of the flow path in FIG. 1. [Figure 4] It is a diagram showing the spectral distribution characteristics of ultraviolet rays emitted from the excimer lamp. [Figure 5] It is a diagram showing the spectral distribution characteristics of ultraviolet rays transmitted through the processing container.

Mode for Carrying Out the Invention

[0019] Hereinafter, with reference to the drawings, an ultraviolet irradiation device including an excimer lamp according to this embodiment will be described.

[0020] FIG. 1 is a cross-sectional view along the lamp axis of the excimer lamp of the ultraviolet irradiation device according to the first embodiment. FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1.

[0021] The ultraviolet irradiation device 1 includes an excimer lamp 10 and a power supply unit (not shown), and a power supply line 70 is connected to the power supply unit. The excimer lamp 10 is configured as an ultraviolet irradiation lamp in which a tubular discharge vessel 20 and a processing vessel (outer vessel) 30 are integrated.

[0022] The discharge vessel 20 is made of a dielectric material such as quartz glass, and an electrode 40 is disposed in the discharge vessel 20 along the tube axis (hereinafter referred to as the lamp axis C). The electrode 40 is configured as a foil electrode extending along the lamp axis C, and one end portion 40T thereof along the lamp axis C direction is connected to a power supply rod (power supply line) 70. Further, the electrode 40 is covered with a dielectric 60 made of quartz glass or the like and is embedded so as not to be exposed to the discharge space S.

[0023] The dielectric 60 has a tapered portion (hereinafter referred to as the enlarged diameter portion) 61 that widens in diameter from near the end 40T of the electrode 40 along the lamp axis C. The bottomed cylindrical portion (hereinafter referred to as the discharge tube) 21 of the discharge container 20 is welded to the enlarged diameter portion 61 at its end 21T1, thereby forming a discharge space S between the discharge tube 21 and the dielectric 60. A rare gas such as xenon gas, or a mixed gas of a rare gas and a halogen gas, is sealed in the discharge space S as the discharge gas.

[0024] The dielectric 60 has an enlarged diameter portion 61 along the lamp axis C and an extended portion 62 extending along the lamp axis C, and the extended portion 62 covers the power supply line 70. The extended portion 62, together with the discharge tube 21, constitutes the discharge container 20. The extended portion 62 also has a first flange-shaped portion (hereinafter referred to as the first thick portion) 63 that protrudes radially, and one end 30T1 of the processing container 30 is welded to the first thick portion 63.

[0025] In the tubular portion of the discharge tube 21, closer to the center (end 21T1) than the other end 21T2, the thickness of the discharge tube 21 is greater than in other parts, and a flange-like portion (hereinafter referred to as the second thickened portion) 23 is formed that protrudes radially. The tubular processing container 30 is made of a dielectric material such as quartz glass, like the discharge container 20, and its other end 30T2 is welded to the second thickened portion 23. In addition, a portion (hereinafter referred to as the exhaust pipe) 22 is formed at the end 21T2 of the discharge tube 21 that protrudes along the lamp axis C.

[0026] The discharge vessel 20 and the processing vessel 30 are covered with a reflective film 50 that reflects ultraviolet light. The reflective film 50 is configured here as an electrode (outer electrode) that is paired with the electrode 40 (hereinafter referred to as the inner electrode). The reflective film 50 is made of a thin metal film, such as an aluminum film.

[0027] As shown in Figure 1, the reflective film 50 covers the discharge container 20 and the processing container 30 from the tip of the exhaust pipe 22 of the discharge container 20 to the central part of the lamp and to the portion of the extended portion 62 that exceeds the first thick portion 63 (hereinafter referred to as the protruding portion) 64. The outer diameter D2 of the extended portion 62, including the protruding portion 64, is larger than the outer diameter D1 of the portion 65 that covers the inner electrode 40 (hereinafter referred to as the small diameter portion).

[0028] A flow path R is formed between the processing container 30 and the discharge container 20 through which the fluid, which is the object to be irradiated with ultraviolet light, flows. Here, gases such as air and liquids such as water are supplied to the ultraviolet irradiation device 100 as the object to be irradiated with ultraviolet light. The processing container 30 has an inlet 31 and an outlet 32. The fluid flows in from the inlet 31 through piping (not shown), flows through the flow path R from end 21T1 to end 21T2, and flows out from the outlet 32. Note that the inlet 31 and outlet 32 ​​are not limited to opening in the same direction in the circumferential direction, but can be configured to open in different directions in the circumferential direction, for example, opening on opposite sides along the radial direction.

[0029] The inlet 31 of the processing container 30 is formed on the protruding portion 64 side of the enlarged diameter portion 61 of the discharge container 20, and faces the spatial region (hereinafter referred to as the end region) R1 formed between the enlarged diameter portion 61 and the first thickened portion 63. The radial distance interval G1 of the end region R1 is longer than the distance interval G2 of the spatial region (hereinafter referred to as the irradiation region) R2 formed between the discharge container 20 and the processing container 30.

[0030] Thus, the outer surface of the tubular portion of the discharge tube 21 surrounded by the irradiation region R2 is closer to the inner surface 30S of the processing container 30 than the outer surface of the extended portion 62 surrounded by the end region R1, forming a lamp structure. Therefore, as the fluid flows from the inlet 31 into the end region R1 and then into the irradiation region R2, the flow in the radial direction of the lamp changes to a flow in the axial direction of the lamp, and the cross-sectional area of ​​the flow path R changes along the flow, causing the fluid to be agitated. Consequently, there is no need to place an agitating member in the flow path, and the ultraviolet rays emitted from the outer surface 20S of the discharge container 20 are not blocked by an agitating member. On the other hand, in the irradiation region R2, the cross-sectional area of ​​the flow path R is approximately constant along the flow, resulting in a uniform flow.

[0031] As shown in Figure 2, the inner electrode 40 and dielectric 60 (small diameter portion 64) are arranged coaxially with respect to the discharge container 20 (discharge tube 21), and the processing container 30 is also arranged coaxially with respect to the discharge container 20. Therefore, the flow path R of the excimer lamp 10 is formed such that the distance interval G2 of its irradiation area R2 is constant along the lamp axis C.

[0032] The inner electrode 40 and the outer electrode, the reflective film 50, have their polarities defined as anode and cathode. High frequency (for example, in the range of several kHz to tens of MHz) and high voltage (for example, in the range of several kV to tens of kV) are supplied to the excimer lamp 10 via the power supply rod 70, and a high-frequency, high-electric field is applied to the discharge space S and the irradiation area R2. As a result, a dielectric barrier discharge occurs in the discharge space S, and excimer light with a predetermined spectrum (here, a peak wavelength of 172 nm) is emitted from the discharge space S and irradiated into the irradiation area R2 (channel R).

[0033] As described above, the inner electrode 40 is a foil electrode, which is formed to be extremely thin relative to its width. It has a flat portion of constant thickness and a sharpened wedge-shaped portion between the ends of the flat portion in the width direction and the ends of the foil electrode in the width direction. The ends of the foil electrode in the width direction are pointed and are so edgy that they appear as points in cross-section.

[0034] The dielectric 60 (small diameter portion 64) has a cross-sectional shape that minimizes the difference in distance from any surface of the foil electrode to the outer surface of the dielectric 60 (thickness to the foil electrode), in accordance with the arrangement and shape of the foil electrode.

[0035] Specifically, the cross-section of the dielectric 60 is defined to be elongated elliptical or oblong. In other words, the cross-section of the dielectric 60 is oval. The dielectric 60 has substantially the same cross-sectional shape over the area covering the foil electrode along the tube axis (lamp axis) C.

[0036] In this manner, the inner electrode 40, which is a foil electrode, is covered with a dielectric 60 having an elongated elliptical or oblong cross-section arranged coaxially, and the dielectric 60 is arranged coaxially with respect to the discharge tube 21. Therefore, the electric field strength does not become excessively large near both ends of the width of the inner electrode 40, and unevenness in discharge along the circumferential direction of the lamp can be prevented.

[0037] On the other hand, because both ends of the inner electrode 40 are pointed (wedge-shaped), even when an irradiation region R2 is interposed around the discharge space S, the electric field concentration makes it easy to start the device with the application of a relatively low voltage. In this way, since the outer electrode is not placed within the irradiation region R2 (outer surface 20S of the discharge container 20), there is no risk of impurities contained in the outer electrode mixing into the fluid.

[0038] The excimer lamp 10 of this embodiment is configured as a small excimer lamp. For example, the axial length (luminescence length) of the discharge container 20 can be set in the range of 20 mm to 400 mm. Also, the outer diameter of the discharge container 20 (discharge tube 21) can be set in the range of 6 mm to 30 mm, preferably in the range of 8 mm to 25 mm.

[0039] The wall thickness of the discharge tube 21 can be set to a range of, for example, 0.7 mm to 2 mm, taking into consideration the prevention of discharge tube degradation due to excimer light and the suppression of an increase in discharge initiation voltage. The inner diameter of the discharge tube 21 can be set to a range of, for example, 4 mm to 28 mm, preferably 5 mm to 23 mm, taking into consideration the suppression of discharge instability due to long discharge distances and insufficient illumination due to short discharge distances.

[0040] The discharge distance, that is, the distance between the outer surface of the dielectric 60 and the inner surface of the discharge tube 21, can be set to a range of 1 mm to 13 mm, preferably 2 mm to 12 mm, taking into consideration the prevention of insufficient illumination due to narrowing of the discharge space and the prevention of discharge instability due to widening of the discharge distance.

[0041] The shape and size of the processing container 30 are determined according to the shape and size of the discharge container 20 described above. Furthermore, the processing container 30 is welded to the discharge container 20 to form the flow path R, which is formed between the discharge container 20 and the processing container 30, in order to effectively treat the flow path R with ultraviolet light while preventing damage to the processing container 30. This will be described in detail below.

[0042] Figure 3 is a magnified view of the area near the flow path in Figure 1. However, the reflective film 50 is not shown in Figure 3.

[0043] In the case of an excimer lamp, it is necessary to determine the distance spacing G2 of the flow channel R formed between the discharge container 20 and the processing container 30 while considering the attenuation characteristics of ultraviolet light. In particular, in the case of ultraviolet light with a wavelength of 172 nm, ultraviolet light is significantly attenuated over short transmission distances. Therefore, if the distance spacing G2 of the flow channel R is too large, when the inner electrode 40 and the reflective film 50 face each other across the discharge space S and the flow channel R, a large ratio of the distance spacing of the flow channel R to the distance spacing of the discharge space S will reduce the applied voltage contributing to the discharge, and the illuminance of the ultraviolet light irradiated into the flow channel R will decrease. Also, if the inner diameter of the processing container 30 is large relative to the outer diameter of the discharge container, it will hinder the thinning of the processing container 30, i.e., the miniaturization of the excimer lamp 10. For this reason, it is desirable to make the distance spacing G2 of the flow channel R as small as possible.

[0044] However, if the distance interval G2 of the flow path R is too small, the processing container 30 will be continuously exposed to excessive ultraviolet light, causing it to break down due to fluid pressure fluctuations before the lamp lifespan at which the discharge container is damaged. In addition, ultraviolet light is absorbed and attenuated by the processing container 30, which is located in a region with high ultraviolet irradiance, thus reducing the ultraviolet treatment efficiency. In order to maintain ultraviolet treatment efficiency and reliability, it is necessary to determine an appropriate distance interval R.

[0045] In this embodiment, with respect to the excimer lamp 10 that emits ultraviolet light with a peak wavelength of 172 nm, the radial distance spacing of the flow path R formed between the discharge container 20 and the processing container 30 is determined based on the attenuation characteristics of ultraviolet light, etc.

[0046] Specifically, the distance (also called the gap) G2 between the outer surface 20S of the discharge container 20 and the inner surface 30S of the processing container 30 is determined such that the ratio of ultraviolet light intensity when transmitted through the outer surface 30M of the processing container 30 is 30% or less. However, the ultraviolet light intensity ratio represents the ratio based on the ultraviolet light intensity at the outer surface 20S of the discharge container 20.

[0047] When the UV intensity ratio exceeds 30%, UV rays absorbed by the fluid pass through the processing container 30 without attenuation, reducing the UV treatment efficiency. Furthermore, if the UV irradiation intensity on the processing container 20 is high, the deterioration of the processing container 30 is accelerated while the lamp is lit. Increasing the thickness of the processing container 30 to prevent damage due to fluid pressure fluctuations would hinder the thinning of the processing container 30, i.e., the miniaturization of the excimer lamp 10.

[0048] As described above, since the processing container 30 is covered with a reflective film 50, ultraviolet light that passes through the outer surface 30M of the processing container 30 is reflected back towards the flow path by the reflective film 50 and reused for ultraviolet treatment. However, the ultraviolet light that is reflected by the reflective film 50 and passes through the processing container 30 again is attenuated, so its effect is limited.

[0049] If most of the ultraviolet light is absorbed and used for ultraviolet treatment (including ozone generation) after it has passed through the outer surface 30M of the treatment container 30, the ultraviolet treatment efficiency can be increased. On the other hand, if the lamp structure is designed so that all the ultraviolet light is absorbed by the fluid flowing through the channel R inside the treatment container 30, the fluid will flow through the area on the inner surface 30S side of the treatment container 30 where the ultraviolet irradiance is low, and the ultraviolet treatment efficiency will decrease.

[0050] By setting the ultraviolet intensity ratio when ultraviolet light passes through the outer surface 30M of the processing container 30 to 30% or less, ultraviolet light that has passed through the processing container 30 is reflected by the reflective film 50, reducing the amount of ultraviolet light that passes through the processing container 30 again and irradiates the fluid. This makes it possible to spend most of the energy of the ultraviolet light emitted from the discharge container 20 on ultraviolet treatment before it passes through the fluid and the processing container 30, thereby increasing the efficiency of ultraviolet treatment.

[0051] Considering that a region of low ultraviolet irradiance should not be formed near the inner surface 30S of the processing container 30, the distance interval G2 can be determined such that the ultraviolet intensity ratio is in the range of 10% to 30%. For example, the distance interval G2 can be determined such that the ultraviolet intensity ratio is 20% or less.

[0052] Furthermore, the distance interval G2 is determined such that the spectral distribution characteristics of ultraviolet light transmitted through the outer surface 30M of the processing container 30 have a maximum at wavelengths longer than 172 nm. Ultraviolet light in the wavelength range of 172 nm and below is easily absorbed by gases containing oxygen (such as air).

[0053] When ultraviolet light with a spectral distribution characteristic where the peak wavelength is longer than 172 nm is transmitted through the outer surface 30M of the processing container 30, it is obtained, resulting in sufficient ultraviolet irradiation of the fluid, and the distance between the processing containers is such that excessive ultraviolet light is not irradiated to them.

[0054] In particular, when oxygen-containing gases such as air are flowed through channel R to generate ozone, ultraviolet light around 172 nm is not absorbed by synthetic quartz glass or nitrogen, but is transmitted. As a result, the ultraviolet light is absorbed by oxygen, and depending on the transmission distance of the oxygen-containing gas (distance between channels R), the peak wavelength shifts from 172 nm to longer wavelengths such as 180 nm or 185 nm. Therefore, by examining the peak wavelength that has shifted to a longer wavelength than 172 nm in the spectral distribution characteristics of ultraviolet light transmitted through the processing container, it is possible to confirm whether absorption by oxygen (ozone generation) is insufficient.

[0055] Furthermore, the distance interval G2 can also be determined from the perspective of illuminance. For example, the distance interval G2 is determined by the irradiance of ultraviolet light transmitted through the outer surface 30M of the processing container 30 being 2 mW / cm². 2 The following conditions are met: Alternatively, the distance interval G2 and the thickness T2 of the processing container 30 are determined to be such that the irradiance is 2 mW / cm². 2 The following conditions are set: On the other hand, the irradiance of the outer surface 20S of the discharge container 20 is 4 mW / cm². 2 In excimer lamps with such high illuminance, it is possible to prevent excessive ultraviolet radiation from being emitted.

[0056] For example, the thickness T1 of the discharge container 20 (discharge tube 21), the thickness T2 of the processing container 30, and the distance G2 between the outer surface 20S of the discharge container 20 and the inner surface 30S of the processing container 30 can be determined as follows, based on the ultraviolet attenuation characteristics, as well as the outer diameter D3 of the discharge tube 21 and the outer diameter D4 of the processing container 30. However, the unit is mm. 0.7 ≤ T1 ≤ 2 0.5 ≤ T2 ≤ 3 0.2 ≤ G2 ≤ ​​6 ...(1)

[0057] As described above, in this embodiment, the excimer lamp 10 is formed by welding a discharge container 20 and a processing container 30 together, and a flow path R, which is a processing space, is formed around the discharge container 20. The distance G2 between the outer surface 20S of the discharge container 20 and the inner surface 30S of the processing container 30 in the flow path R is determined such that the ultraviolet intensity ratio of ultraviolet light transmitted through the outer surface 30M of the processing container 30 is 30% or less.

[0058] Furthermore, the material of the processing container is not limited to quartz glass with high ultraviolet transmittance (such as synthetic quartz glass), but can also be used with relatively inexpensive quartz glass with low ultraviolet transmittance (such as fused quartz glass), or materials that do not transmit ultraviolet light.

[0059] The excimer lamp may also be configured to include an external electrode other than the reflective film. For example, a cord-like conductive member can be wrapped around the outer surface of the processing container. Alternatively, a configuration may be provided in which an ultraviolet-transparent partition wall is placed inside the processing container to create multiple flow channels.

[0060] For example, by arranging a partition wall concentrically with the processing container to form two channels, flowing a fluid with high UV transmittance (air) through the inner channel and a fluid with low UV transmittance (water) through the outer channel, the distance interval G2 can be determined such that the UV intensity ratio of the UV rays passing through the inner channel, partition wall, outer channel, and processing container is 30% or less.

[0061] Furthermore, the processing container can be configured not to be welded to the excimer lamp. In addition, for excimer lamps that emit ultraviolet light with a peak wavelength other than 172 nm, the distance interval G2 can be determined according to the ultraviolet attenuation characteristics and spectral distribution characteristics. [Examples]

[0062] The following describes an example of an excimer lamp using Figures 4 and 5.

[0063] The excimer lamp in this embodiment corresponds to the excimer lamp of the embodiment described above and is configured as an integrated excimer lamp in which a processing container is welded to a discharge container. However, the outer electrode is replaced with a configuration in which a conductive linear member, which is wrapped around the outer surface of the processing container, is spirally wound around the outer surface of the processing container, instead of a reflective film.

[0064] In this setup, the discharge vessel has a thickness of 1 mm, the processing vessel has a thickness of 1 mm, and the distance between the outer surface of the discharge vessel and the inner surface of the processing vessel is 5 mm. The discharge space is filled with xenon gas or a mixed gas containing xenon gas.

[0065] The excimer lamp was activated, and the ultraviolet irradiance on the outer surface of the processing container was measured using a measuring instrument (ultraviolet irradiance meter). As a result, it was confirmed that the ultraviolet intensity ratio was 30% or less. However, the ultraviolet irradiance on the outer surface of the discharge container was measured using an excimer lamp manufactured without welding the processing container to the discharge container.

[0066] Furthermore, when the spectral distribution characteristics of ultraviolet light were measured using a measuring instrument (spectroradiometer), it was confirmed that there was a maximum value at wavelengths longer than 172 nm, as shown in the distribution curve L2 in Figure 5. Note that the ultraviolet light distribution curve L1 shown in Figure 4 was obtained from an excimer lamp in which the processing container was not welded to the discharge container.

[0067] Furthermore, when the ultraviolet irradiance on the outer surface of the processing container and the outer surface of the discharge container was measured using a measuring instrument (ultraviolet irradiance meter), it was found to be 2 mW / cm². 2 Below, 4mW / cm 2 The above was confirmed. However, the ultraviolet irradiance on the outer surface of the discharge vessel was measured by manufacturing an excimer lamp in which the processing vessel was not welded to the discharge vessel. [Explanation of Symbols]

[0068] 1 Ultraviolet irradiation device 10 Excimer Lamps 20 Discharge container 21 Discharge tube 30 Processing Containers 40 Electrode (Inner Electrode) 50 Reflective film (outer electrode) 60 Electrophores G2 Distance Interval

Claims

1. A discharge vessel that forms a discharge space, The system includes a processing vessel that covers the discharge vessel and forms a processing space between itself and the discharge vessel, which serves as a flow path for the fluid to be irradiated with ultraviolet light, An ultraviolet irradiation device characterized in that the distance between the outer surface of the discharge container and the inner surface of the processing container is determined such that when excimer light having a peak wavelength of 172 nm is transmitted through the outer surface of the processing container by discharge, the ultraviolet intensity is 30% or less.

2. The ultraviolet irradiation apparatus according to claim 1, characterized in that the distance between the outer surface of the discharge vessel and the inner surface of the processing vessel is determined such that the ultraviolet intensity distribution when the excimer light passes through the outer surface of the processing vessel has a maximum at wavelengths longer than 172 nm.

3. The distance between the outer surface of the discharge container and the inner surface of the processing container is such that the irradiance when the excimer light passes through the outer surface of the processing container is 2 mW / cm². ２ The ultraviolet irradiation device according to claim 1, characterized in that it is defined as follows:

4. The excimer light irradiance at the outer surface of the discharge vessel is 4 mW / cm² ２ The ultraviolet irradiation device according to claim 1, characterized in that it is as described above.

5. The distance between the outer surface of the discharge container and the inner surface of the processing container, and the thickness of the processing container, are such that the excimer light irradiance at the outer surface of the processing container is 2 mW / cm². ２ The ultraviolet irradiation device according to claim 1, characterized in that it is defined as follows:

6. The ultraviolet irradiation device according to claim 1, characterized in that the thickness T1 of the discharge vessel, the thickness T2 of the processing vessel, and the distance G2 between the outer surface of the discharge vessel and the inner surface of the processing vessel are set to the following ranges. 0.7 ≦ T1 (mm) ≦ 2 0.5 ≦ T2 (mm) ≦ 3 0.2 ≦ G2 (mm) ≦ 6

7. The ultraviolet irradiation apparatus according to any one of claims 1 to 6, characterized in that the processing container is welded to and integrated with the discharge container so as to form the flow path between the discharge container and the processing container.

8. A tubular discharge vessel, The system includes a tubular processing container that covers the discharge container and forms a flow path between it and the discharge container, An excimer lamp characterized in that the distance between the outer surface of the discharge container and the inner surface of the processing container is determined such that when excimer light having a peak wavelength of 172 nm is transmitted through the outer surface of the processing container by discharge, the ultraviolet intensity is 30% or less.

9. A method of ultraviolet irradiation using an ultraviolet irradiation device comprising a discharge vessel that forms a discharge space, and a processing vessel that covers the discharge vessel and forms a processing space between it and the discharge vessel that serves as a flow path for a fluid to be irradiated with ultraviolet light, The distance between the outer surface of the discharge container and the inner surface of the processing container is determined such that when excimer light having a peak wavelength of 172 nm is transmitted through the outer surface of the processing container by discharge, the ultraviolet intensity is 30% or less. A method of ultraviolet irradiation characterized by emitting ultraviolet light from a discharge space through an electrical discharge.

Images