Discharge lamp, ozone generation method, and manufacturing method of discharge vessel

Abstract

To effectively irradiate a channel in which raw material gas or the like flows with ultraviolet rays in an ozone generation device or the like.SOLUTION: An excimer lamp 10 includes an outer tube 20 and an inner tube 30. Strip-shaped foil electrodes 40A and 40B are embedded between the outer tube 20 and the inner tube 30, and are prevented from being exposed owing to a partial welding of the outer tube 20 and the inner tube 30. A flow path R is formed between the outer tube 20 and the inner tube 30.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a discharge lamp such as an excimer lamp, an ultraviolet ray irradiation device using an excimer lamp, and an ozone generator, and in particular to the configuration of a discharge vessel. [Background technology]

[0002] In excimer lamps with a double-tube structure in which the arc tube is made up of an inner tube and an outer tube, the outer tube and the inner tube are fused together at the sealing portion and sealed together (see, for example, Patent Document 1). A rare gas is sealed in the discharge space formed between the inner tube and the outer tube, and light is emitted by discharge when a high-frequency voltage is applied between the electrodes.

[0003] In an ozone generator using an excimer lamp, it is necessary to form a flow path so that the raw material gas for ozone generation can be effectively irradiated with ultraviolet rays. For example, an excimer lamp with a double-tube structure is placed in a cylindrical housing, and a flow path through which the raw material gas flows is formed between the outer surface of the outer tube and the inner surface of the housing. (See Patent Documents 2 and 3.) [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5504095 [Patent Document 2] JP 2003-165711 A [Patent Document 3] JP 2016-37416 A Summary of the Invention [Problem to be solved by the invention]

[0005] Depending on the ultraviolet light of a certain wavelength (e.g., 172 nm), the ultraviolet light emitted from the lamp is attenuated over a relatively short distance. Therefore, in the flow path through which the raw material gas flows, there may be a spatial region where the ultraviolet light intensity is insufficient, which may lead to a decrease in the efficiency of ozone generation.

[0006] Therefore, there is a demand for a discharge vessel having a configuration that can effectively irradiate ultraviolet rays onto the flow path through which the raw material gas flows. [Means for solving the problem]

[0007] The discharge lamp of the present invention comprises an inner tube, an outer tube that houses the inner tube, and a strip electrode disposed between the inner tube and the outer tube. The inner tube and the outer tube are partially fused together so as not to expose the strip electrode, and a first spatial region is formed within the inner tube, and a second spatial region is formed in the unfused spatial portion between the inner tube and the outer tube. In the first spatial region and the second spatial region, a discharge space is formed in one, and a flow path is formed in the other.

[0008] For example, the first spatial region can be formed as a discharge space, and the second spatial region can be formed as a flow path. In this case, the strip electrodes can be configured as an electrode pair arranged opposite each other via an inner tube. On the other hand, the first spatial region can be formed as a flow path, and the second spatial region can be formed as a discharge space.

[0009] When the discharge space is formed in the first spatial region, the flow path can be configured to have an axial flow path along the tube axis and a radial flow path connected to the axial flow path along one surface of the reduced diameter portion of the inner tube. Alternatively, the flow path can be configured to have an axial flow path along the tube axis and open at one end of the outer tube. In this case, the radial distance between the outer surface of the inner tube and the inner surface of the outer tube can be configured to be equal to or less than the ultraviolet attenuation distance at which the ultraviolet attenuation rate is 80% or more.

[0010] On the other hand, when the flow passage is formed in the first spatial region, the flow passage can be configured such that at least one end of the inner tube is opened to provide an axial flow passage along the tube axis.

[0011] One aspect of the present invention is an ozone generation method in which a strip electrode is placed between an inner tube and an outer tube that houses the inner tube, the inner tube and the outer tube are welded together so that the strip electrode is embedded, a rare gas for emitting ultraviolet rays is sealed in a discharge space formed in the inner tube, a flow path is formed in the unwelded space between the inner tube and the outer tube, and a raw material gas containing oxygen is flowed through the flow path to generate ozone.

[0012] A method for producing a discharge vessel according to one aspect of the present invention includes disposing a strip electrode between an inner tube and an outer tube housing the inner tube, partially welding the inner tube and the outer tube so as to embed the strip electrode, and forming a spatial region in the unwelded space between the inner tube and the outer tube. The spatial region may be a spatial region (first space) that becomes a discharge space or a flow path, and a spatial region (second spatial region) that becomes a flow path or a discharge space, by partially welding the inner tube and the outer tube. Effect of the Invention

[0013] According to the present invention, in an ozone generator or the like, a flow path through which a raw material gas or the like flows can be effectively irradiated with ultraviolet light. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic side view of an excimer lamp according to a first embodiment. [Diagram 2] 1 is a schematic plan view of an excimer lamp according to a first embodiment, as viewed from the axial direction. [Diagram 3] FIG. 1 is a schematic cross-sectional view of an excimer lamp. [Figure 4] 2A to 2C are diagrams illustrating a manufacturing process of the excimer lamp according to the first embodiment. [Diagram 5] 2A to 2C are diagrams illustrating a manufacturing process of the excimer lamp according to the first embodiment. [Figure 6] FIG. 11 is a schematic side view of an excimer lamp in a second embodiment. [Figure 7] 11 is a schematic plan view of an excimer lamp according to a second embodiment, as viewed from the axial direction. FIG. [Figure 8] FIG. 11 is a schematic cross-sectional view of an excimer lamp in a second embodiment. [Figure 9] 5A to 5C are diagrams illustrating a manufacturing process of the excimer lamp according to the second embodiment. [Figure 10] 5A to 5C are diagrams illustrating a manufacturing process of the excimer lamp according to the second embodiment. [Figure 11] FIG. 11 is a schematic side view of an excimer lamp in a third embodiment. [Figure 12] FIG. 11 is a schematic plan view of an excimer lamp according to a third embodiment, as viewed from the axial direction. [Figure 13] FIG. 11 is a schematic cross-sectional view of an excimer lamp in a third embodiment. [Figure 14] 10A to 10C are diagrams illustrating a manufacturing process of an excimer lamp according to a third embodiment. [Figure 15] 10A to 10C are diagrams illustrating a manufacturing process of an excimer lamp according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0016] Fig. 1 is a schematic side view of an excimer lamp according to a first embodiment of the present invention, and Fig. 2 is a schematic plan view of the excimer lamp as viewed from the axial direction.

[0017] The excimer lamp 10 is a discharge lamp with a double-tube structure in which a flow path R is formed in a discharge vessel 10F, and is connected to a flow path pipe 80 via connections 60, 70. The flow path pipe 80 is configured to allow a raw material gas (such as a gas containing oxygen) for generating ozone or a liquid to be irradiated with ultraviolet light for sterilization or deodorization to flow therethrough.

[0018] The excimer lamp 10 comprises an outer tube 20 and an inner tube 30 arranged coaxially within the outer tube 20. A discharge space S is formed within the inner tube 30, and rare gas is sealed in through a tip tube 35 so as to radiate ultraviolet light of a desired wavelength outward from the inner tube 30. The outer tube 20 and the inner tube 30 are made of materials that can be fused together by heating, and in this case, are made of quartz glass that is transparent at a desired wavelength. In addition, in Figures 1 and 2, flow paths R1 and R2 surrounded by the inner surface 20S of the outer tube 20 and the outer surface 30S of the inner tube 30 are shown by dashed lines.

[0019] The electrode pair 40A, 40B extends along the tube axis C, and here is constituted by band-shaped foil electrodes. The electrode pair 40A, 40B is provided at positions facing each other along the radial direction between the inner tube 30 and the outer tube 20. Power supply lines 50A, 50B are respectively connected to the electrode pair 40A, 40B at the end of the inner tube 30 opposite the tip tube 35.

[0020] 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 electrode pair 40A, 40B, a discharge (dielectric barrier discharge, etc.) is generated in the discharge space S, and ultraviolet rays are emitted as excimer light from the discharge space S. Here, ultraviolet rays with a wavelength of 172 nm are emitted.

[0021] For example, when a raw material gas containing oxygen flows through the flow path pipe 80, ozone is generated by irradiating the raw material gas flowing through the flow path R in the excimer lamp 10 with ultraviolet light. The raw material gas containing ozone flows out into the flow path pipe 80 through the lower connecting part 70 and is used for sterilization, deodorization, and the like.

[0022] 3 is a schematic cross-sectional view of the excimer lamp 10. Here, cross-sectional views are shown along lines AA, BB, and CC shown in FIGS.

[0023] As is clear from the cross-sectional view taken along line CC in Fig. 3, the electrode pair 40A, 40B is disposed facing each other along the radial direction while being sandwiched between the outer tube 20 and the inner tube 30, and is embedded by welding the outer tube 20 and the inner tube 30, and is not exposed to the spatial region. As is clear from the cross-sectional view taken along line AA in Fig. 3, the length of the electrode pair 40A, 40B along the tube axis C corresponds to the constant diameter portion 30T0 of the inner tube 30, and the entire electrode pair 40A, 40B is covered by welding the outer tube 20 and the inner tube 30, and is not exposed.

[0024] In addition, the boundary 30M between the reduced diameter portion 30T2 on the opposite side of the tip tube 35 of the inner tube 30 and the constant diameter portion In the vicinity of the outer pipe 20, the outer pipe 20 is welded to the entire circumferential circumference of the inner pipe 30. Due to such partial welding of the outer pipe 20 and the inner pipe 30, a flow path R is formed as a gap along the radial direction of the outer pipe 20 and the inner pipe 30, which is a non-welded portion between the outer pipe 20 and the inner pipe 30.

[0025] 1 and the cross-sectional view along the line BB in Fig. 3, the flow path R on the upstream side (connection portion 60 side) of the outer pipe 20 and the flow path R on the downstream side (connection portion 70 side) (in Fig. 3, indicated by reference symbol R1 as a flow path along the axial direction) are configured as axial flow paths along the pipe axis C. The upstream and downstream flow paths R1 along the axial direction are spatially connected in the radial direction through a flow path R (in Fig. 3, indicated by reference symbol R2 as a flow path along the radial direction) along the outer surface of the reduced diameter portion 30T1 on the side where the tip tube 35 of the inner pipe 30 is formed.

[0026] In the discharge vessel 10F, a discharge space S is formed within the inner tube 30, and a space that forms a flow path R between the outer tube 20 and the inner tube 30 is formed, but the discharge space S occupies most of the discharge vessel 10F, and the spatial area of ​​the flow path R is very narrow.

[0027] In general, vacuum ultraviolet rays of a certain peak wavelength attenuate as the light travels through the atmosphere, decreasing the intensity of the ultraviolet rays. In particular, in an ideal measurement environment, for ultraviolet rays with a wavelength of 172 nm, the ultraviolet intensity ratio attenuates to 80% after traveling about 1 mm, 50% after about 3 mm, 20% after about 6 mm, and All of the ultraviolet light is absorbed at a distance of about 30 mm. The distance over which the ultraviolet light attenuation rate reaches 80% or more (ultraviolet light intensity ratio is 20% or less) (hereinafter referred to as the ultraviolet light attenuation distance) is very short, but if the raw material gas passes through an area with low ultraviolet light intensity, it is not possible to generate a gas containing a high concentration of ozone. Therefore, it is necessary to form a flow path R that allows the raw material gas or liquid to pass through an area with sufficient ultraviolet light intensity to generate ozone while flowing through the flow path R.

[0028] In this embodiment, the radial distance of the flow path R (R1) formed in the excimer lamp 10, i.e., the distance (hereinafter referred to as the gap) K between the inner tube outer surface 30S and the outer tube inner surface 20S, is equal to or less than the ultraviolet ray attenuation distance even at the point where the distance is maximum. This prevents the formation of an area with low ultraviolet ray intensity in the flow path R, and allows ultraviolet rays to be irradiated with sufficient ultraviolet ray intensity to the source gas, liquid, etc. passing through the flow path R (R1). In addition, the gap of the flow path R has no significant difference in distance along the path, and the source gas or liquid can receive ultraviolet rays with a relatively uniform ultraviolet ray intensity while flowing through the flow path R (R1).

[0029] Furthermore, when a discharge occurs in the discharge space S, ultraviolet rays are not only emitted in the radial direction of the discharge space S, i.e., from the entire circumferential direction of the inner tube 30, but also in the direction along the tube axis C. Since the flow paths R (R1, R2) are formed along most of the outer surface 30S including the reduced diameter portion 30T2 of the inner tube 30, the raw material gas or liquid can be sufficiently irradiated with ultraviolet rays while passing through the flow paths R.

[0030] Such an excimer lamp 10 having a double tube structure does not require insertion or installation into a jacket tube, as is the case with existing excimer lamps, and can be configured as an ozone generator by simply connecting it to the flow path tube 80, and can also be configured as an ultraviolet ray irradiation device.

[0031] 4 and 5 are diagrams showing the manufacturing process of the excimer lamp 10 of this embodiment. The manufacturing method will be described with reference to Figures 4 and 5. However, cross-sectional views of the inner tube and outer tube aligned with lines AA and BB in Figures 1 and 2 are also shown. Furthermore, for ease of explanation, the configurations of the outer tube and tubes corresponding to the inner tube after manufacture shown in Figures 1 to 3 are given the same reference numerals as in Figures 1 to 3.

[0032] First, a small-diameter tip tube is formed at one end, and a bottomed inner tube is molded with the other end closed to form an internal space. For the outer tube, a small-diameter opening is formed at a position opposite to the top-bottom direction to serve as a connection part with the flow path tube, and a small-diameter hole 20R corresponding to the tip tube size of the inner tube is formed at one end, and an outer tube without a bottom is molded with an open end opposite to the small-diameter hole 20R (the tip tube of the inner tube).

[0033] After the inner and outer tubes are formed, the inner tube is inserted into the outer tube, and at this time, the belt-shaped foil electrodes to which the power supply lines are connected are inserted into the outer tube while being maintained in mutually opposing positions in the circumferential direction (see step 1-1).

[0034] Figure 4 shows the state in which the inner tube is inserted into the outer tube. The gap between the inner and outer tubes is very small (exaggerated in Figure 4) just large enough to insert the foil electrode, and the diameters of the inner and outer tubes are determined according to the thickness of the foil electrode.

[0035] After the inner tube is inserted into the outer tube, both sides of the outer tube are sealed. That is, the gap between the small diameter at one end of the outer tube and the tip tube of the inner tube, and the opening on the opposite side are sealed by heating. Then, the upper opening of the outer tube is closed and a vacuum is drawn from the lower opening (see step 1-2).

[0036] After sealing the lower opening of the outer tube and creating a vacuum inside the outer tube, the outer tube is heated and reduced in diameter along the position of the foil electrode to weld the outer tube to the inner tube. At this time, the outer tube is heated without rotating to maintain the position of the foil electrode. As a result, the outer tube and the inner tube are welded together with the foil electrode embedded between them. The inner tube is open to the atmosphere.

[0037] As the foil electrode portion is sealed, the outer tube is heated and reduced in diameter around the boundary 30M between the constant diameter portion of the inner tube and the reduced diameter portion on the opposite side of the tip tube, and the outer tube is welded to the entire circumference of the inner tube. This forms a flow path between the outer tube and the inner tube (see step 1-3). The inner tube is then evacuated and filled with discharge gas, after which the end of the outer tube is cut to match the end of the inner tube. The upper and lower sealed portions of the outer tube are then opened again to form connections (see step 1-4). Through this series of steps, the excimer lamp 10 is manufactured.

[0038] Next, an excimer lamp according to a second embodiment will be described with reference to Figures 6 to 10. In the second embodiment, the tip tube of the inner tube is provided on the power supply line side.

[0039] Fig. 6 is a schematic side view of an excimer lamp in the second embodiment, Fig. 7 is a schematic plan view of an excimer lamp in the axial direction in the second embodiment, and Fig. 8 is a schematic cross-sectional view of an excimer lamp in the second embodiment.

[0040] As in the first embodiment, the excimer lamp 100 comprises an outer tube 120 and an inner tube 130 coaxially housed within the outer tube 120, and a discharge space S is formed within the inner tube 130, while a flow path R is formed between the outer tube 120 and the inner tube 130.

[0041] As shown in the cross-sectional view taken along lines AA and BB in Fig. 8, at the opposite end of the tip tube 135 of the inner tube, a flow path R (indicated by reference symbol R2 in Fig. 8) is radially connected to the upstream and downstream flow paths R (indicated by reference symbol R1 in Fig. 8) along the tube axis C, allowing the source gas, liquid, etc. to pass through the excimer lamp 10. Unlike the first embodiment, no tip tube is formed on the side of flow path R2, so a wide spatial region can be secured for flow path R2, and ultraviolet rays can be sufficiently irradiated onto the source gas, etc.

[0042] 9 and 10 are diagrams showing the manufacturing process of the excimer lamp in the second embodiment. The manufacturing method of the excimer lamp in the second embodiment will be described with reference to FIGS.

[0043] For the inner tube, a small-diameter tip tube is formed at one end, and a cylindrical inner tube with a closed bottom is formed at the other end to form an internal space. For the outer tube, a small-diameter tip tube 125 is formed at one end, and an opening 120A is formed at the other end. Then, the inner tube is inserted into the outer tube with the tip tube side of the inner tube facing the tip tube of the outer tube (see step 2-1). At this time, as in the first embodiment, the foil electrode is inserted into the outer tube along the inner tube.

[0044] After the inner tube is inserted, both ends of the outer tube, i.e., the opening 120A and the tip tube 125, are sealed to form the end 120B, and the inside of the outer tube is evacuated (see step 2-2). Then, the outer tube is heated and reduced in diameter along the foil electrode to weld the outer tube to the inner tube. The outer tube is also welded to the inner tube around the entire circumference near the boundary 130M between the reduced diameter portion and the constant diameter portion on the tip tube side of the inner tube to form a flow path (see step 2-3).

[0045] Thereafter, the inner tube is evacuated and filled with discharge gas, the tip tube of the inner tube is sealed, and the tip tube side of the outer tube is cut from the entire circumferential welded portion with the inner tube. Then, after the inner tube is tipped off, i.e., cut and sealed, the upper and lower sealed portions of the outer tube are opened again to form connections (see step 2-4). In this way, the excimer lamp 100 of the second embodiment is manufactured.

[0046] Next, an excimer lamp according to a third embodiment will be described with reference to Figures 11 to 15. In the third embodiment, a discharge vessel is configured with one end of an outer tube being open. The rest of the configuration is substantially the same as that of the second embodiment.

[0047] Fig. 11 is a schematic side view of an excimer lamp in the third embodiment, Fig. 12 is a schematic plan view of the excimer lamp in the axial direction in the third embodiment, and Fig. 13 is a schematic cross-sectional view of the excimer lamp in the third embodiment.

[0048] The excimer lamp 200 includes an outer tube 220 and an inner tube 230. An opening 220R is formed at one end of the outer tube 220, and the outer tube 220 has no bottom. A source gas containing oxygen flows in from both of the connections 60 and 70 of the outer tube 220.

[0049] The gas that has flowed into the excimer lamp 200 is irradiated with ultraviolet light while passing through an axial flow path R (R1) along the tube axis C, generating ozone. Then, the gas containing ozone flows out from the opening 220R. By allowing the gas containing ozone to flow out from the opening 220R in this way, for example, by positioning the excimer lamp 200 so that the opening 220R of the outer tube 220 faces the surface of the workpiece W (see FIG. 11), it is possible to use the excimer lamp 200 as an ozone generator with sterilizing and deodorizing effects.

[0050] 14 and 15 are diagrams showing the manufacturing process of the excimer lamp in the third embodiment. The manufacturing method of the excimer lamp in the third embodiment will be described with reference to Figs.

[0051] As in the second embodiment, the inner tube is inserted into the outer tube with the foil electrode attached, and the outer tube and inner tube are welded together so as not to expose the foil electrode. The outer tube is also welded around the entire circumference of the inner tube near the boundary between the reduced diameter section and the constant diameter section on the tip tube side of the inner tube (see step 3-3 in Figure 14).

[0052] Thereafter, the end of the outer tube opposite the tip tube is cut to form an opening. The tip tube of the inner tube is sealed (see step 3-4 in FIG. 14). A rare gas is then enclosed in the inner tube to seal the tip tube. The upper and lower sealed portions of the outer tube are opened again to form connections (see step 3-5 in FIG. 15). This completes the manufacture of the excimer lamp 200 of the third embodiment.

[0053] In the first to third embodiments, a pair of band-shaped foil electrodes are used, but three or more electrodes may be used, and one electrode of the electrode pair may be disposed on the outer surface of the outer tube. It is also possible to use electrodes other than foil electrodes that extend along the tube axis. Furthermore, it is also possible to configure the electrodes with a length shorter than the length of the constant diameter portion of the inner tube.

[0054] In the first to third embodiments, the inside of the inner tube is formed as a discharge space, and the space between the inner tube and the outer tube is formed as a flow path, but it is also possible to switch the flow path and the discharge space as spatial regions. For example, it is possible to form a flow path by penetrating the inside of the inner tube along the tube axis direction, and to form a discharge space between the inner tube and the outer tube. The flow path can be configured to provide an axial flow path along the tube axis by opening at least one of the inner tubes. In this case, an electrode may be embedded in the tube wall of the outer tube, or an electrode may be disposed on the outer surface of the outer tube. [Explanation of symbols]

[0055] 10 Excimer Lamp 20 Outer tube 30 inner tube 40A foil electrode 40B foil electrode S discharge space R flow path

Claims

1. An inner tube; an outer tube containing the inner tube; a strip electrode disposed between the inner tube and the outer tube; the inner tube and the outer tube are partially welded together so as not to expose the strip electrodes; A first spatial region is defined within the inner tube; A second spatial region is formed in a non-welded spatial portion between the inner tube and the outer tube, In the first spatial region and the second spatial region, A discharge lamp, characterized in that a discharge space is formed on one side and a flow path is formed on the other side.

2. The discharge space is formed in the first spatial region, 2. The discharge lamp according to claim 1, wherein the flow passage is formed in the second spatial region.

3. 3. The discharge lamp according to claim 2, wherein the flow passage has an axial flow passage along a tube axis and a radial flow passage connected to the axial flow passage along one surface of the reduced diameter portion of the inner tube.

4. 3. The discharge lamp according to claim 2, wherein the flow passage provides an axial flow passage along a tube axis, and one end of the outer tube is open.

5. A discharge lamp as described in any one of claims 2 to 4, characterized in that in the flow path, the radial distance between the outer surface of the inner tube and the inner surface of the outer tube is equal to or less than the ultraviolet attenuation distance at which the ultraviolet attenuation rate is 80% or more.

6. 6. The discharge lamp according to claim 1, wherein the strip electrodes are constituted by an electrode pair disposed opposite each other with the inner tube interposed therebetween.

7. The flow path is formed in the first spatial region, 2. The discharge lamp according to claim 1, wherein the discharge space is formed in the second spatial region.

8. At least one end of the inner tube is open; 8. The discharge lamp according to claim 7, wherein the flow passage is an axial flow passage along the tube axis.

9. A strip electrode is disposed between an inner tube and an outer tube that houses the inner tube; the inner tube and the outer tube are welded together so as to embed the strip electrodes therein; A rare gas for emitting ultraviolet rays is sealed in a discharge space formed in the inner tube; forming a flow passage in a non-welded space portion between the inner pipe and the outer pipe; An ozone generating method, comprising the steps of: generating ozone by flowing a raw material gas containing oxygen through the flow path.

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