Excimer lamp

Abstract

An excimer lamp effectively irradiates an object to be exposed to ultraviolet light. [Solution] The excimer lamp of the ultraviolet irradiation device comprises a discharge container 520 and a processing container 530. The dielectric 560 of the discharge container 520 is provided with an enlarged diameter portion 561, and the discharge tube 521 of the discharge container 520 is provided with a large diameter portion 523. The processing container 530 is welded to the enlarged diameter portion 561 and the large diameter portion 523, forming a flow path R around the discharge container 520 through which the fluid, which is the object to be irradiated with ultraviolet light, flows.

Description

Technical Field

[0001] The present invention relates to an excimer lamp.

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 processed or the like. Also, ozone can be generated by irradiating an ozone-generating source gas with ultraviolet rays.

[0003] In an ultraviolet irradiation device and an ozone generation device, it is required to effectively irradiate ultraviolet rays onto a flow path through which a source gas or the like flows. For example, an ultraviolet irradiation device in which an ultraviolet irradiation space is provided around a light-emitting tube is known (see Patent Document 1). In that device, a light-emitting tube and an outer tube are arranged concentrically, and an object to be irradiated with ultraviolet rays, such as water, is supplied to and discharged from a processing space therebetween.

[0004] Also, an ozone generation device in which an excimer lamp having a double-tube structure is arranged in a cylindrical housing and a flow path through which a source gas flows is formed is known (see Patent Document 2). In that device, the excimer lamp is inserted into an outer tube, and a flow path tube for ozone generation and a flow path tube through which a cooling medium flows are provided.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the case of excimer lamps, the flow channels surrounding the discharge tube must be constructed to match its size, making it difficult to form flow channels along the lamp surface while maintaining a distance that does not attenuate ultraviolet light.

[0007] Therefore, it is necessary to effectively irradiate objects with ultraviolet light using an excimer lamp. [Means for solving the problem]

[0008] The excimer lamp of the present invention is applicable to ultraviolet irradiation devices and comprises an electrode and a tubular discharge vessel that forms a discharge space around the electrode. The configuration of the electrode (inner electrode) can vary. It is not limited to a foil electrode covered with a dielectric material; the inner electrode may be rod-shaped or plate-shaped. Furthermore, it is possible to configure the inner electrode to be exposed to the discharge space.

[0009] The excimer lamp of the present invention comprises a tubular discharge container that forms a discharge space and an outer container that forms a flow path between it and the discharge container, wherein at least one end of the flow path along the lamp axis direction is formed closer to the center in the lamp axis direction than the end of the discharge container.

[0010] For example, at least one end of the flow path along the lamp axis direction can be formed closer to the center in the lamp axis direction than the end of the cylindrical portion of the discharge vessel. In the cylindrical portion of the discharge vessel, the gap distance of the flow path can be kept constant along the lamp axis.

[0011] The gap distance along the ramp radius of the flow path can be less than or equal to the thickness of the outer container. For example, the gap distance along the ramp radius of the flow path can be set to a range of 0.2 mm or more and 2 mm or less.

[0012] For example, an excimer lamp can be constructed that includes a pair of electrodes provided inside the discharge container and outside the outer container. At least one end of the flow path can be formed on the lamp axial end side beyond the range where the pair of electrodes face each other.

[0013] For example, an excimer lamp can be constructed with an inner electrode inside the discharge chamber. At least one end of the flow path can be formed on the lamp axial end side of the end of the inner electrode.

[0014] The other end of the flow path can be formed extending beyond the end of the cylindrical portion of the discharge vessel, towards the end in the lamp axis direction. Furthermore, the length of the flow path along the lamp axis direction can be configured to be longer than the length of the cylindrical portion along the lamp axis direction.

[0015] Another embodiment of the present invention, an excimer lamp, further comprises a container (referred to here as an outer container) that covers the discharge vessel and forms a flow path between it and the discharge vessel. For example, the outer container is provided with an inlet and an outlet (flow path tube), and a fluid such as a gas or liquid flows through the flow path.

[0016] An excimer lamp can irradiate a fluid flowing through a channel with ultraviolet light, or irradiate an object contained within the lamp with ultraviolet light. The outer container can take various forms; for example, the cylindrical portion surrounding the discharge space of the discharge container can be formed with a circular cross-section. It can also be positioned coaxially with respect to the discharge container. In this configuration, the channel is formed around the discharge space, extending throughout the entire circumferential direction of the discharge container.

[0017] In this invention, the outer container is integrated with the discharge container by welding it to the discharge container. For example, an outer container made of a glass material such as quartz glass can be welded to the discharge container to create a single unit. The outer container can be welded to surround the discharge container.

[0018] Another embodiment of the present invention is an excimer lamp that forms a flow path around the discharge space and combines an ultraviolet irradiation lamp and a processing container for an object to be exposed to ultraviolet light. Such an excimer lamp is effective for ultraviolet irradiation devices that emit ultraviolet light with a peak wavelength that undergoes significant attenuation when transmitted through a fluid.

[0019] Regarding the welded part between the discharge capacitor and the outer container, various welding methods are possible. For example, the outer container is welded near the end along the lamp axis direction of the discharge capacitor so as to be out of the discharge region. Alternatively, the outer container can be welded to the discharge capacitor near the flow path pipe (such as the inlet and outlet) connected to the flow path.

[0020] For example, in the cylindrical portion surrounding the discharge space of the discharge capacitor, the outer container can be welded to the discharge capacitor such that the distance interval (width) of the flow path is substantially constant and the flow direction and cross-sectional area of the flow path change near the end of the discharge capacitor.

[0021] The outer container may be welded to a protruding portion compared to other parts of the discharge capacitor. As the protruding portion, for example, a flange-like portion can be formed on the discharge capacitor.

[0022] The form of the discharge capacitor is various, and an extending portion extending from one end can be provided. For example, the extending portion can be configured as a part of the dielectric covering the electrode. In that case, the flange-like portion can be provided on the extending portion.

[0023] Also, the outer container can be configured to be welded to the end of the discharge capacitor. Alternatively, the outer container can be welded to the exhaust pipe formed at or near the end of the discharge capacitor.

[0024] The outer container may be covered with a reflective film that reflects ultraviolet rays. For example, a reflective film is provided that covers the discharge capacitor from the lamp center part to the lamp end side beyond the welded part between the outer container and the discharge capacitor along the tube axis, and reflects the ultraviolet rays radiated from the discharge space. The reflective film can cover the outer surface of the flow path pipe provided on the outer container and connected to the flow path.

[0025] Regarding the configuration of the outer electrode facing the above electrode, there are various possibilities. The outer electrode can be provided on the outer surface side of the processing container. For example, the above reflective film can be configured as the outer electrode. Also, an electrode arrangement can be adopted where a linear electrode is wound around the outer surface of the outer container.

Advantages of the Invention

[0026] According to the present invention, in an excimer lamp, ultraviolet rays can be effectively irradiated onto an object to be irradiated with ultraviolet rays.

Brief Description of the Drawings

[0027] [Figure 1] FIG. 1 is a cross-sectional view along the lamp axis of an excimer lamp of an ultraviolet irradiation device according to the first embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1. [Figure 3] FIG. 3 is a cross-sectional view of an excimer lamp according to the first modification. [Figure 4] FIG. 4 is a cross-sectional view of an excimer lamp according to the second modification. [Figure 5] FIG. 5 is a cross-sectional view of an excimer lamp of an ultraviolet irradiation device according to the second embodiment. [Figure 6] FIG. 6 is a cross-sectional view of an excimer lamp of an ultraviolet irradiation device according to the third embodiment. [Figure 7] FIG. 7 is a cross-sectional view of an excimer lamp showing the third modification of the first embodiment.

Embodiments for Carrying Out the Invention

[0028] Hereinafter, an ultraviolet irradiation device provided with an excimer lamp according to the present embodiment will be described with reference to the drawings.

[0029] FIG. 1 is a cross-sectional view along the lamp axis of an excimer lamp of an ultraviolet irradiation device according to the first embodiment. FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1.

[0030] The ultraviolet irradiation device 500 comprises an excimer lamp 510 and a power supply unit (not shown), with a power supply line 70 connected to the power supply unit. The excimer lamp 510 is configured as an ultraviolet irradiation lamp integrating a tubular discharge container 520 and a processing container (outer container) 530. Here, a gas such as air, or a liquid such as water, is supplied to the ultraviolet irradiation device 500 as the object to be irradiated with ultraviolet light.

[0031] The discharge container 520 is made of a dielectric material such as quartz glass, and electrodes 40 are arranged inside the discharge container 520 along the tube axis (hereinafter referred to as the lamp axis C). The electrodes 40 are configured as foil electrodes extending along the lamp axis C, and one end 40T1 along the direction of the lamp axis C is connected to a power supply rod (power supply line) 70.

[0032] The electrode 40 is covered with a dielectric 560 made of quartz glass or the like, and is embedded so as not to be exposed in the discharge space S. The dielectric 560 extends along the lamp axis C and has a tapered portion (hereinafter referred to as the enlarged diameter portion) 561 in which the diameter increases from near the end 40T1 of the electrode 40.

[0033] The discharge container 520 has a bottomed cylindrical portion (hereinafter referred to as the discharge tube) 521, which is welded to an enlarged diameter portion 561 at its end 521T1. The discharge space S formed between the discharge tube 521 and the dielectric 560 is sealed with a rare gas such as xenon gas, or a mixed gas of a rare gas and a halogen gas, as the discharge gas.

[0034] The discharge tube 521 is formed in a bottomed cylindrical shape with the discharge tube end (hereinafter also referred to as the tip surface) 521T3 as the bottom. The discharge tube 521 has a cylindrical portion (hereinafter referred to as the cylindrical portion) 521K with a constant diameter along the lamp axis C, and a shoulder portion 521R2 from the end 521T2 of the cylindrical portion 521K toward the tip surface 521T3, with the diameter decreasing toward the tip surface 521T3. A protruding portion (hereinafter referred to as the exhaust pipe) 522 is formed along the lamp axis C on the tip surface 521T3 of the discharge tube 521, protruding along the lamp axis C. The tip 560T2 of the dielectric 560 reaches the internal space of the exhaust pipe 522.

[0035] The shoulder portion 521R2 has a larger thickness and outer diameter of the discharge tube 521 compared to other parts, and a protruding portion (hereinafter referred to as the large-diameter portion) 523 is formed that protrudes radially from the inner surface of the processing container 530. The outer diameter D5 of the large-diameter portion 523 is larger than the inner diameter D4 of the processing container 530 and smaller than the outer diameter D6 of the processing container 530.

[0036] The dielectric 560 has a protruding portion (hereinafter referred to as the extended portion) 562 that extends outward from the enlarged diameter portion 561 beyond the discharge tube range L3. The extended portion 562 extends along the lamp axis C and covers the power supply line 70. The section L3 along the lamp axis C from the shoulder portion 521R2 of the discharge tube 521 to the enlarged diameter portion 561 of the dielectric 560 is referred to here as the discharge tube range. The section L2 in which the cylindrical portion 521 is formed is referred to here as the cylindrical range.

[0037] The tubular processing container 530, like the discharge container 520, is made of a dielectric material such as quartz glass. One end 530T1 of the processing container 530 is welded to the enlarged diameter portion 561 of the dielectric material 560, and the other end 530T2 is welded to the large diameter portion 523. The ends 530T1 and 530T2 of the processing container 530 become the ends RT1 and RT2 of the flow path R, respectively.

[0038] The discharge vessel 520 and the processing vessel 530 are covered with a reflective film 50 that reflects ultraviolet light. The reflective film 50 is configured here as an electrode (outer electrode) provided outside the processing vessel 530 that is paired with the electrode 40 (hereinafter referred to as the inner electrode) provided inside the discharge vessel 520. The reflective film 50 is made of a thin metal film, such as an aluminum film.

[0039] As shown in Figure 1, the reflective film 50 covers the discharge container 520 and the processing container 530 from the tip of the exhaust pipe 522 on the exposed tip surface 521T3 that is not covered by the processing container 530, to the central part of the lamp, and to the extended part 562 that extends beyond the enlarged diameter part 561 towards the lamp end.

[0040] The pair of electrodes, consisting of an inner electrode 40 and an outer electrode, a reflective film 50, are arranged facing each other along the radial direction of the lamp in a range L1 along the lamp axis (hereinafter referred to as the electrode-facing range). The outer diameter D2 of the extended portion 562 is larger than the outer diameter D1 of the portion 565 that covers the inner electrode 40 (hereinafter referred to as the small-diameter portion).

[0041] A flow path R is formed between the processing container 530 and the discharge container 520 through which the fluid, which is the object to be irradiated with ultraviolet light, flows. One end RT2 of the flow path R, that is, one end 530T2 of the processing container 530, is located along the lamp axis C, on the lamp axis side of the center in the lamp axis direction, i.e., in the discharge tube range L3, compared to the tip surface 521T3 of the discharge tube 521. Also, one end RT2 of the flow path R is located on the lamp axis side of the electrode facing range L1.

[0042] The other end RT1 of the flow path R, i.e., the other end 530T1 of the processing container 530, is located along the ramp axis C, closer to the center in the ramp axis direction than the enlarged diameter portion 561 of the discharge container 520, i.e., within the discharge tube range L3. The section L4 of the flow path R from end RT1 to end RT2 (hereinafter referred to as the flow path length) is longer than the electrode facing range L1 and shorter than the discharge tube range L3.

[0043] The processing container 530 has an inlet 531 and an outlet 532. Fluid flows in through piping (not shown) from the inlet (flow channel) 531, flows along the direction from end RT1 to end RT2, and flows out from the outlet (flow channel) 532. Note that the inlet 531 and outlet 532 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.

[0044] The inlet 531 of the processing container 530 is formed near the end RT1 of the flow path R and faces the enlarged diameter portion 561 of the discharge container 520 along the ramp radial direction. The inlet 531 may also be configured to face the end 40T1 of the inner electrode 40 along the ramp radial direction.

[0045] The outlet 532 of the processing container 530 is formed near the end RT2 of the flow path R on the central side of the lamp, rather than the large diameter portion 523, and faces the end 40T2 of the inner electrode 40 along the lamp radial direction. The outlet 532 may also be configured to face the dielectric 560 (end 560T2) along the lamp radial direction, further towards the lamp tip than the end 40T1 of the inner electrode 40.

[0046] Light emitted from the discharge space S is transmitted to the inlet 531 and outlet 532. By placing a light sensor near the inlet 531 or outlet 532, or by visual inspection, it is possible to detect the light emitted from the inlet 531 or outlet 532 to the outside of the lamp, and the lamp lighting status of the excimer lamp 510 can be confirmed.

[0047] It is also possible to reverse the direction of the fluid flow so that it flows from the outlet 532 to the inlet 531. In this case as well, the fluid that flows in from the outlet 532 and is irradiated with ultraviolet light will flow out from the inlet 531.

[0048] The fluid velocity (flow rate) of the fluid flowing through channel R can be measured in various ways. For example, it is possible to adjust the flow velocity according to the intensity of ultraviolet light, and it is also possible to intermittently flow the fluid (stop the flow) so that the fluid receiving ultraviolet irradiation is temporarily stopped within the cylindrical region R2 (channel R).

[0049] As shown in Figure 2, the inner electrode 40 and dielectric 560 are arranged coaxially with respect to the discharge vessel 520 (discharge tube 521), and the processing vessel 530 is also arranged coaxially with respect to the discharge vessel 520. The flow path R of the excimer lamp 510 is formed such that the gap distance G2 between its cylindrical regions R2 is constant along the lamp axis C.

[0050] The inner electrode 40 and the outer electrode, the reflective film 50, have their polarities set as anode and cathode, respectively, and are opposed to each other in the radial direction of the lamp within the electrode opposing range L1. High frequency (e.g., in the range of several kHz to tens of MHz) and high voltage (e.g., in the range of several kV to tens of kV) are supplied to the excimer lamp 510 via the feed rod 70, and a high-frequency, high-electric field is applied to the discharge space S and the cylindrical region R2. As a result, a dielectric barrier discharge occurs in the discharge region of the discharge space S, and excimer light with a predetermined spectrum (e.g., wavelength 172 nm) is emitted from the discharge space S and irradiated into the cylindrical region R2 (channel R).

[0051] 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.

[0052] The dielectric 560 (small diameter portion 565) 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 560 (thickness to the foil electrode), in accordance with the arrangement and shape of the foil electrode.

[0053] Specifically, the cross-section of the dielectric 560 along the lamp's radial direction is defined to be either an elongated ellipse or an oblong shape. In other words, the cross-section of the dielectric 560 is oval-shaped. The dielectric 560 maintains a substantially identical cross-sectional shape throughout the area covering the foil electrode along the tube axis (lamp axis) C.

[0054] In this manner, the inner electrode 40, which is a foil electrode, is covered with a dielectric 560 having an elongated elliptical or oblong cross-section arranged coaxially, and the dielectric 560 is arranged coaxially with respect to the discharge tube 520. Therefore, the electric field strength does not become excessively large near both ends of the inner electrode 40, and unevenness in discharge along the circumferential direction of the lamp can be prevented.

[0055] On the other hand, because both ends of the inner electrode 40 are pointed (wedge-shaped), even when a cylindrical 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 inside the cylindrical region R2 (outer surface 520S of the discharge container 520), there is no risk of impurities contained in the outer electrode mixing with the fluid.

[0056] The configuration of the inner electrode 40 can vary. It is not limited to a foil electrode covered with dielectric 560 as described above; it may also be a rod-shaped or plate-shaped inner electrode. Furthermore, it is possible to configure the inner electrode to be exposed to the discharge space.

[0057] In this embodiment, the excimer lamp 510 can have, for example, an axial length (luminescence length) of the discharge container 520 set to a range of 20 mm to 400 mm. Furthermore, the outer diameter of the discharge container 520 (discharge tube 521) can be set to a range of 6 mm to 30 mm, preferably 8 mm to 25 mm.

[0058] The wall thickness of the discharge tube 521 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 521 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.

[0059] The discharge distance, that is, the distance between the outer surface of the dielectric 560 and the inner surface of the discharge tube 521, 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.

[0060] The shape and size of the processing container 530 are determined based on the ultraviolet intensity, the flow characteristics of the fluid to be irradiated with ultraviolet light (flow velocity, flow rate, pressure), and the size of the discharge container 520, for example, the outer diameter D3 of the discharge tube 521 and the outer diameter D6 of the processing container 530.

[0061] For example, the thickness T1 of the discharge container 520 (discharge tube 521) is set to a range of 0.7 mm to 2 mm. The thickness T2 of the processing container 530 is set to a range of 0.5 mm to 3 mm. The gap distance R2 of the cylindrical region R2 of the flow path R, that is, the distance G2 between the outer surface of the cylindrical portion 521K of the discharge container 520 and the inner surface of the processing container 530, is set to be less than or equal to the thickness T2 of the processing container 530. Here, the distance G2 is set to a range of 0.2 mm to 6 mm. Preferably, it can be set to a range of 0.2 mm to 2 mm.

[0062] As described above, the excimer lamp 510 of this embodiment is configured such that the discharge container 520 and the processing container 530 are welded together, and the flow path R, which is the processing space, is formed in the cylindrical portion 521K of the discharge tube 521 around the discharge container 520. Because the lamp structure has a discharge space S formed around the inner electrode 40, the flow path R becomes an annular (cylindrical) space along the outer surface of the discharge container 520 (discharge tube 521), and ultraviolet rays radiated from the discharge space S over the entire circumference of the discharge tube 521 can be effectively irradiated onto the fluid.

[0063] Furthermore, not only is ultraviolet light emitted from the discharge vessel 520 transmitted, but through multiple reflections, ultraviolet light also travels through the dielectric 560 and the inside of the discharge tube 521's wall, and is transmitted to the inside of the processing vessel 530's wall. This effect of transmitting ultraviolet light, similar to that of an optical fiber, allows ultraviolet light to be irradiated onto the fluid in the flow path R from all sides. In particular, since both the discharge vessel 520 and the processing vessel 530 are made of the same material, such as quartz glass, and are integrated with the enlarged diameter section 561 and the large diameter section 523 of the discharge vessel 520 by welding, ultraviolet light can easily be transmitted to the inside of the processing vessel 530's wall.

[0064] Furthermore, because the reflective film 50 covers the discharge container 520 and the processing container 530, ultraviolet light can be irradiated onto the fluid from the reflective film 50 side. In addition, since the reflective film 50 functions as an outer electrode in close contact with the discharge container 520, the luminescence efficiency in the discharge space S and the reflection efficiency by the reflective film 50 can be increased.

[0065] Since the processing container 530 is welded to the enlarged diameter portion 561 and the large diameter portion 523 located near both ends of the discharge container 520, the discharge container 520 and the processing container 530 can be coaxially positioned with high precision. In particular, when the gap distance G2 between the cylindrical region R2 of the flow path R is smaller than the thickness T1 of the discharge container 520 (discharge tube 521), and even smaller than the thickness T2 of the processing container 530, the discharge container 520 and the processing container 530 can be coaxially positioned with high precision.

[0066] This makes it possible to make the gap distance of the flow path R, that is, the distance G2 (mm) between the outer surface of the cylindrical portion 521K of the discharge container 520 and the inner surface of the processing container 530, uniform in the circumferential direction within the cylindrical region R2 surrounding the cylindrical portion 521K. In addition, because the enlarged diameter portion 561 and the large diameter portion 523 are thicker than the extended portion 562 and the other parts of the discharge tube 521, it is possible to prevent lamp damage originating from the welded portion caused by sudden pressure changes due to fluid velocity (flow rate) adjustment.

[0067] In particular, the outer surface of the large-diameter portion 523, which is formed to have an outer diameter smaller than the outer diameter of the processing container 530, is formed in a curved shape so that the radial thickness changes continuously along the axial direction. Furthermore, the outer surface of the welded portion between the large-diameter portion 523 and the end portion 530T2 is formed in a curved shape so that the outer circumferential surface of the processing container 530 and the outer circumferential surface of the discharge container 520 are continuously connected.

[0068] This not only increases the thickness of the welded portion and enhances the mechanical strength near the end of the flow path, preventing lamp damage, but also suppresses the formation of minute wedge-shaped voids on the outer surface of the welded portion, which can be the starting point for lamp damage, and allows the outer surface to be covered without gaps by the reflective film (outer electrode). The outer surface of the welded portion between the enlarged diameter portion 561 and the end portion 530T1 may also be formed in a curved shape in the same way.

[0069] Such an excimer lamp 510 can be manufactured, for example, by the following manufacturing method.

[0070] First, a convex portion (large-diameter section) is formed on the discharge tube, which has openings at both ends, having an outer diameter larger than the inner diameter of the insertion opening of the processing container. Additionally, an exhaust pipe is welded to one of the openings (exhaust port) of the discharge tube.

[0071] Then, a dielectric material, which has a sealing portion covering the electrode and an enlarged diameter portion, is inserted into the other opening (insertion port) of the discharge tube. At this time, the dielectric material is inserted so that its tip reaches the internal space of the exhaust tube.

[0072] After inserting the dielectric, the discharge vessel is formed by welding the other opening (insertion port) of the discharge tube to the enlarged diameter portion. The diameter of the enlarged diameter portion of the dielectric may be larger than the inner diameter of the insertion port of the processing vessel.

[0073] Next, an inlet and an outlet are formed near both ends, and a discharge container is inserted into the tubular processing container, which has openings at both ends, through one of the openings (insertion port). At this time, the larger diameter portion of the discharge container is brought into contact with (fitted) the opening.

[0074] The large-diameter portion of the discharge vessel acts as a support structure that supports the opening (end) of the processing vessel, thereby coaxially positioning (temporarily fixing) the processing vessel with respect to the discharge vessel. Alternatively, the processing vessel may be temporarily fixed by the enlarged diameter portion. Then, the end (opening) of the processing vessel is welded to the large-diameter portion and the enlarged diameter portion of the discharge vessel.

[0075] In this way, before welding the discharge vessel and the processing vessel together, the large-diameter portion (or enlarged diameter portion) of the discharge vessel supports the end of the processing vessel, allowing the discharge vessel and the processing vessel to be precisely coaxially aligned before welding.

[0076] Furthermore, since the large-diameter section (enlarged diameter section) also serves as a support member that seals the flow path, there is no need to place a support member inside the flow path, so ultraviolet rays emitted from the outer surface of the discharge vessel are not blocked by the support member. In addition, there is no risk of abnormal discharge (creepage discharge) occurring along the support member in the flow path where high frequency and high voltage are applied while sandwiched between a pair of electrodes.

[0077] Regarding the protruding portion, instead of configuring it to protrude from the large-diameter portion (or enlarged-diameter portion) where the outer diameter of the discharge tube is larger than other parts, i.e., from the entire circumference, it may be configured to protrude from only a part of the circumference. For example, a hemispherical or cylindrical projection may be provided on a part of the circumference of the discharge tube, and the end (opening) of the outer container before welding may be brought into contact with the projection and supported coaxially so that it is welded together as one unit.

[0078] Impurities are removed by vacuuming through the exhaust pipe, and then discharge gas is sealed inside. The exhaust pipe is then sealed by heating and deformation. An outer electrode (reflective film) is placed on the outer surface, extending from the tip of the sealed exhaust pipe to the center of the lamp, and further along the pipe axis to the lamp end beyond the welded portion between the outer container and the discharge container. By thoroughly removing impurities after welding the discharge container and the processing container and before sealing in the discharge gas, the desired lamp performance can be obtained.

[0079] The flow path formed by welding the discharge vessel 520 and the processing vessel 530 is not limited to a configuration in which protruding portions are provided on the extended portion and shoulder portion of the discharge vessel, but welding as shown below is also possible.

[0080] Figure 3 is a cross-sectional view of the first modified example, an excimer lamp.

[0081] The ultraviolet irradiation device 1 comprises an excimer lamp 10 and a power supply unit (not shown), with a power supply line 70 connected to the power supply unit. The excimer lamp 10 is configured as an ultraviolet irradiation lamp that integrates a tubular discharge container 20 and a processing container (outer container) 30.

[0082] A non-sealed portion 60P is provided between the tip 40T2 of the electrode 40 and the tip 60T2 of the dielectric 60, and is not sealed to the electrode 40. Inside the non-sealed portion 60P, a discharge space (hereinafter referred to as the auxiliary discharge space) P for ignition startup is formed. The auxiliary discharge space P is under reduced pressure below atmospheric pressure. It is also possible to seal a rare gas, which lowers the voltage during ignition startup, in the auxiliary discharge space P at a pressure below atmospheric pressure.

[0083] The discharge tube 21 of the discharge container 20 is welded to the expanded diameter portion 61 of the dielectric at its end 21T1. The discharge tube 21 has a bottomed cylindrical structure with a shoulder portion 21R2 between its bottom end surface 21T3 and a cylindrical portion 21K with a constant diameter along the lamp axis C. In addition, a protruding portion (exhaust pipe) 22 is formed at the end 21T3 of the discharge tube 21, protruding along the lamp axis C.

[0084] The stretched portion 62 of the dielectric 60 has a larger thickness and outer diameter compared to other parts, and has a radially protruding portion (hereinafter referred to as the flange portion) 63. One end 30T1 of the processing container 30 is welded to the flange portion 63 to form the end RT1 of the flow path R.

[0085] In the cylindrical portion 21K of the discharge tube 21, near its end 21T2, the thickness and outer diameter of the discharge tube 21 are larger than in other parts, and a protruding portion (large diameter portion) 23 is formed that protrudes radially beyond the inner surface of the processing container 30. The outer diameter D5 of the large diameter portion 23 is larger than the inner diameter D4 of the processing container 30 and smaller than the outer diameter D6 of the processing container 30.

[0086] The discharge container 20 and the processing container 30 are covered with a reflective film 50 that reflects ultraviolet light. The reflective film 50 covers the discharge container 20 and the processing container 30, extending to the portion of the extended portion 62 that is exposed (exposed portion) 64 and not covered by the processing container 30. The outer diameter D2 of the extended portion 62, including the exposed 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).

[0087] One end RT2 of the flow path R on the exhaust pipe 22 side is formed on the lamp axis-center side of the front end surface 21T3 of the discharge container 20, i.e., within the discharge tube range L3. Here, the end RT2 is formed on the lamp axis-center side of the end 21T2 of the cylindrical portion 21K of the discharge container 20, i.e., within the cylindrical range L2, and is also outside the electrode facing range L1 and on the lamp axis-end side of the end 40T2 of the inner electrode 40.

[0088] The other end RT1 of the flow path R on the exposed portion 64 side is formed on the lamp axial end side of the enlarged diameter portion 61 of the discharge container 20, i.e., outside the discharge tube range L3. The section L4 of the flow path R from end RT2 to end RT1 (hereinafter referred to as the flow path length) is longer than the discharge tube range L3.

[0089] The inlet 31 of the processing container 30 is formed near the end RT1 of the flow path R. The end RT1 is located along the ramp axis C, on the ramp end side (outside the cylindrical range L2) of the cylindrical portion 21K of the discharge tube 21, and on the exposed portion 64 side (outside the discharge tube range L3) of the enlarged diameter portion 61 of the discharge container 20. Furthermore, the end RT1 faces the spatial region (hereinafter referred to as the enlarged region) R1. The enlarged region R1 is located between the enlarged diameter portion 61 and the flange portion 63, and has a larger cross-sectional area of ​​the flow path compared to other parts.

[0090] The gap distance along the radial direction of the expanded region R1, that is, the distance G1 between the outer surface of the extended portion 62 and the inner surface of the processing container 30, is longer than the gap distance of the cylindrical space region (cylindrical region) R2 surrounding the cylindrical portion 21K, that is, the distance G2 between the outer surface of the cylindrical portion 21K and the inner surface of the processing container 30.

[0091] The outlet 32 ​​of the processing container 30 is formed near the end RT2 of the flow path R on the central side of the lamp, rather than the large diameter portion 23, and faces the auxiliary discharge space P (unsealed portion 60P) along the radial direction of the lamp.

[0092] Such an excimer lamp 10 can be manufactured by the same manufacturing method as described above, except for the configuration in which the end (opening) of the processing container is welded to a flange-shaped portion.

[0093] Figure 4 is a cross-sectional view of a second modified example, an excimer lamp.

[0094] The excimer lamp 100 comprises a discharge container 120 and a processing container 130. The flange-shaped portion 163 of the extended portion 162 of the discharge container 120 (dielectric 160) has an outer diameter D5 that is larger than the outer diameter of the cylindrical portion 121K of the discharge tube 121 and the inner diameter of the processing container 130, and preferably smaller than the outer diameter of the processing container 130.

[0095] The processing container 130 is welded to its flange-shaped portion 163 at one end (inlet) 130T1, and to the exhaust pipe 122, which is a protruding portion of the discharge container 120 (discharge tube 121), at the other end 130T2. The welding forms the ends RT1 and RT2 of the flow path R.

[0096] Similar to the first modification of the first embodiment, the flange portion of the discharge vessel supports the end of the processing vessel, allowing the discharge vessel and the processing vessel to be precisely coaxially positioned before welding.

[0097] An enlarged region R1 is formed near the inlet 131 of the flow path R. In the second modified example, an enlarged region R3 is formed near the outlet 132 of the flow path R, on the tip side of the exhaust pipe 122, rather than on the cylindrical portion 121K along the ramp axis.

[0098] The enlarged region R3 is formed between the outer surface of the exhaust pipe 122, the outer surface of the end portion 121T3 and shoulder portion 121R2 of the discharge pipe 121, and the inner surface of the end portion 130T2 of the processing container 130. The radial gap distance of the enlarged region R3, that is, the distance between the outer surface of the exhaust pipe 122 and the inner surface of the processing container 130 (hereinafter also referred to as the gap distance) G3, is longer than the distance G1 of the enlarged region R1 and the distance G2 of the cylindrical region R2.

[0099] Thus, a lamp structure is provided in which the outer surface of the discharge container 120 surrounded by the cylindrical region R2 is closer to the inner surface of the processing container 130 than the outer surface of the discharge container 120 surrounded by the expanded region R1. Furthermore, the expanded region R3 having the outlet 132 is formed beyond the discharge tube range L3 towards the exhaust pipe 122 side, and the flow path length L4 of the flow path R is longer towards both ends of the lamp than the discharge tube range L3 (cylindrical range L2) along the lamp axis C. Ultraviolet light emitted from the discharge space S is irradiated onto the fluid flowing through the flow path R, which is formed to be longer along the lamp axis C.

[0100] The end 130T2 of the processing container 130 may be welded to the shoulder portion 121R2 formed between the exhaust pipe end 121T3 of the discharge tube 121 and the end 121T2 of the cylindrical portion 121K. In this case, in order to integrate the shoulder portion 121R2 and the large-diameter portion 163, the outer diameter of the shoulder portion 21R2 of the discharge tube 121 is formed to be larger than that of other parts.

[0101] Next, a second embodiment of the ultraviolet irradiation device will be described using Figure 5. In the second embodiment, the welded portion between the discharge vessel and the processing vessel is provided in the discharge tube.

[0102] Figure 5 is a cross-sectional view of the excimer lamp of the ultraviolet irradiation device according to the second embodiment.

[0103] The excimer lamp 300 comprises a tubular discharge container 320 and a processing container 330. The end portion 321T1 of the discharge tube 321 constituting the discharge container 320 is welded to the enlarged diameter portion 361 of the dielectric 360, similar to the first embodiment. On the other hand, the cylindrical portion 321K of the discharge tube 321 is provided with a large-diameter portion 323 that is larger in thickness and outer diameter than other parts and protrudes radially from the inner surface of the processing container 330, on the lamp center (tip surface 321T3) side from the end portion 321T1.

[0104] The outer diameter D5 of the large-diameter portion 323 is larger than the inner diameter of the processing container 330, and in this case, it is formed to be smaller than the outer diameter of the processing container 330. One end 330T1 of the processing container 330 is welded to the large-diameter portion 323 to form the end RT1 of the flow path R. The other end 330T2 is welded to the cylindrical outer surface of the exhaust pipe 322 that protrudes along the ramp axis C of the discharge container 320 to form the end RT2 of the flow path R.

[0105] The inlet 331 of the processing container 330 is located closer to the center of the lamp than the large-diameter portion 323 of the discharge container 320, and is positioned opposite the end 40T1 of the inner electrode 40 along the lamp radial direction. The outlet 332 of the processing container 330 is located closer to the tip of the exhaust pipe 322 than the cylindrical range L2. The flow path length L4 of the flow path R is longer than the cylindrical range L2.

[0106] The large-diameter portion 323 of the discharge container 320 has an outer diameter that is larger than the outer diameter of the cylindrical portion 321K of the discharge tube 321 and the inner diameter of the processing container 330, but smaller than the outer diameter of the processing container 330. By welding the end portion 330T1 of the processing container 330 to the large-diameter portion 323, the large-diameter portion of the discharge container supports the end portion of the processing container before welding the discharge container and the processing container together, allowing them to be coaxially positioned with high precision.

[0107] On the other hand, since the inlet 331 is formed in a position facing the inner electrode 40, ultraviolet light is also irradiated onto the fluid near the inlet 331, allowing ultraviolet light to be irradiated over the entire flow path R from the inlet 331 to the outlet 332.

[0108] In addition to welding the end portion 321T1 of the discharge tube 321 to the enlarged diameter portion 361 of the dielectric 360, the large-diameter portion 323 of the discharge tube 321 may also be welded to the enlarged diameter portion 361. In this case, the enlarged diameter portion 361 and the large-diameter portion 323 are formed integrally, and the outer diameter of the end portion 321T1 of the discharge tube 321 is formed to be larger than that of other parts.

[0109] The end portion 330T2 of the processing container 330 may be configured to be welded to a large-diameter portion provided on the shoulder portion 321R2 of the discharge tube 321, similar to the first embodiment. Alternatively, it may be configured to be welded to a large-diameter portion provided on the tip surface side of the cylindrical portion of the discharge tube 321, similar to the first modification of the first embodiment.

[0110] Such an excimer lamp 300 can be manufactured, for example, by the following manufacturing method.

[0111] First, the exhaust pipe is welded to one end, forming a large-diameter section on the discharge tube, which has both ends open and has a large-diameter section. This section has an outer diameter larger than the inner diameter of the insertion port of the processing container. Then, the exhaust pipe is welded to one of the openings (exhaust port) of the discharge tube.

[0112] Next, the discharge tube is inserted into a processing container with an inlet and outlet at both ends, through one of the openings (insertion port), and the larger diameter portion of the discharge tube is brought into contact with (fitted) the opening.

[0113] The large-diameter portion of the discharge tube acts as a support structure that supports the opening (end) of the processing container, thereby coaxially positioning (temporarily fixing) the processing container to the discharge tube. Then, one end (opening) of the processing container is welded to the large-diameter portion of the discharge tube, and the other end is welded to the outer surface of the exhaust tube.

[0114] An enlarged section is formed, and a dielectric covering the electrodes is inserted into the discharge tube so that a portion of its tip reaches the internal space of the exhaust pipe. After insertion, the end of the discharge tube is welded to the enlarged section of the dielectric. After welding, a vacuum is drawn through the exhaust pipe to remove impurities. Then, after sealing in the discharge gas, the exhaust pipe is sealed by heating and deformation. An outer electrode (reflective film) is placed on the outer surface of the sealed exhaust pipe, extending from the tip to the center of the lamp, along the tube axis, to a portion of the exposed area beyond the flange-like section.

[0115] In this way, by welding the discharge tube and the processing container to form a flow path, and then welding the discharge tube and the dielectric to form a discharge space, the ingress of impurities into the discharge tube during welding of the processing container is suppressed, and the desired lamp performance can be obtained.

[0116] Next, a third embodiment of the excimer lamp will be described using Figure 6. In the third embodiment, the discharge tube extends beyond the enlarged diameter portion of the dielectric, and a large-diameter portion is provided in the extended portion.

[0117] Figure 6 is a cross-sectional view of an excimer lamp according to a third embodiment.

[0118] The excimer lamp 400 comprises a discharge vessel 420 and a processing vessel 430. The discharge tube 421 constituting the discharge vessel 420 has an extended portion 424 that extends along the lamp axis C beyond the enlarged diameter portion 461 of the dielectric 460. A part of the extended portion 424 of the discharge tube 421 is provided with a large-diameter portion 423 that is larger in thickness and outer diameter than other parts and protrudes radially beyond the inner surface of the processing vessel 430.

[0119] One end 430T1 of the processing container 430 is welded to the large-diameter portion 423 of the discharge tube 421 to form the end RT1 of the flow path R, and the other end 430T2 is welded to the exhaust tube 422, which is a protruding portion that extends along the ramp axis C of the discharge tube 421, to form the end RT2 of the flow path R.

[0120] The inlet 431 of the processing container 430 is located closer to the center of the lamp than the large-diameter portion 423 of the discharge container 420, and is positioned opposite the enlarged diameter portion 461. The outlet 432 of the processing container 430 is located closer to the tip of the exhaust pipe 422 than the end portion 40T2 of the inner electrode 40. The flow path length L4 of the flow path R is longer than the discharge tube range L3.

[0121] By providing a large-diameter portion 423 in the extended portion 424 of the discharge vessel 420, the processing vessel 430 extends beyond the enlarged diameter portion 461 of the discharge vessel 420 and into the extended portion 462. As a result, the length L4 of the flow path R along the ramp axis C becomes larger, and along the ramp axis C it is longer towards both ends of the ramp than the discharge tube range L3 (cylindrical range L2). Light emitted from the discharge space S passes through the enlarged diameter portion 461 and the extended portion 424 and irradiates the fluid.

[0122] Furthermore, the reflective film 50 covers the discharge container 420 and the processing container 430 from the tip of the exhaust pipe 422 of the discharge container 420 to the central part of the lamp and beyond the large-diameter portion 423 of the extended portion 424, while the end portion 424T of the extended portion 424 is not covered by the reflective film 50. By exposing the end portion 424T of the extended portion 424, surface discharge and abnormal discharge due to dielectric breakdown via the extended portion 462 of the dielectric 460 can be suppressed between the reflective film 50 and the power supply rod 70.

[0123] Regarding the extended portion 424, instead of configuring it as part of the discharge tube 421 as described above, it may be prepared as a separate component and welded to the discharge tube 421. For example, it is possible to use synthetic quartz glass with high ultraviolet transmittance for the discharge tube and relatively inexpensive fused quartz for the extended portion. Alternatively, a thin quartz glass may be used for the discharge tube to increase ultraviolet transmittance, and a thicker glass tube may be used as the extended portion.

[0124] Furthermore, in addition to welding the end portion 421T1 of the discharge tube 421 to the enlarged diameter portion 461 of the dielectric 460, the large diameter portion 423 may also be welded. In this case, the thickness of the end portion 421T1 of the discharge tube 421 is made thicker than the other portions. The end portion 430T2 of the processing container 430 may also be configured to be welded to the large diameter portion provided on the shoulder portion 421R2 of the discharge tube 421, similar to the first embodiment. Alternatively, similar to the first modification of the first embodiment, the large diameter portion provided on the tip surface side of the cylindrical portion of the discharge tube 421 may be welded to it.

[0125] Such an excimer lamp 400 can be manufactured, for example, by the following manufacturing method.

[0126] First, a large-diameter portion is formed on the discharge tube, which has openings at both ends, having an outer diameter larger than the inner diameter of the insertion opening of the processing container. An exhaust pipe is welded to one opening (exhaust port) of the discharge tube, and a dielectric material covering the electrodes is inserted through the other opening (insertion port) of the discharge tube. Then, the other opening (insertion port) of the discharge tube is welded to the enlarged portion of the dielectric material to form the discharge container.

[0127] Next, the discharge container is inserted into the processing container, which has an inlet and outlet at both ends and is open at both ends, from one of the openings (the insertion port), and the large-diameter portion of the discharge container is brought into contact (fitted) with this opening. The large-diameter portion of the discharge container becomes a support structure that supports the opening (end) of the processing container, thereby positioning (temporarily fixing) the processing container coaxially with the discharge container. Then, one end (opening) of the processing container is welded to the large-diameter portion of the discharge tube, and the other end is welded to the outer surface of the exhaust tube.

[0128] Vacuum is drawn through the exhaust pipe to remove impurities. Then, after sealing in the discharge gas, the exhaust pipe is sealed by heating and deformation, and an outer electrode (reflective film) is placed on the outer surface between the tip of the welded exhaust pipe and a portion of the extended section.

[0129] In the first to third embodiments, a reflective film is provided as the outer electrode, but it is also possible to provide electrodes of other forms.

[0130] Figure 7 is a cross-sectional view of an excimer lamp showing a third modified example of the first embodiment. Except for the configuration of the outer electrodes, it has the same configuration as the second modified example of the first embodiment (see Figure 4).

[0131] In the excimer lamp 200', the outer electrode 50' is provided on the outer circumferential surface of the processing container 230. The outer electrode 50' is spirally wound around the outer circumferential surface of the processing container 230 along the lamp axis C between conductive cylindrical members 51A and 51B, and is arranged to be spaced apart at predetermined intervals. With this configuration, ultraviolet light can be transmitted through the extended portion 262 of the discharge container 220 to the inside of the tube wall of the processing container 230 via multiple reflections, effectively irradiating the fluid with ultraviolet light.

[0132] The excimer lamp described above is characterized by a configuration in which the processing container is welded to the discharge container and integrated into one unit. With this configuration, it is possible to determine the inlet and outlet positions according to the axial length of the inner electrode, that is, the opposing section between the reflective film and the inner electrode (electrode opposing range L1), and to adjust the space of the flow path R along the lamp axis.

[0133] Furthermore, by forming the thickened portion around the stretched portion of the dielectric or around the outer surface of the discharge tube, it is possible to suppress lamp damage originating from the welded portion due to sudden pressure changes in the fluid. In addition, ultraviolet rays emitted from the discharge space can be sufficiently irradiated onto the fluid flowing into and out of the excimer lamp. [Explanation of Symbols]

[0134] 1 Ultraviolet irradiation device 10 Excimer Lamps 20 Discharge container 21 Discharge tube 23 Large diameter section 30 Processing containers 40 electrodes (inner electrode) 50 Reflective film (outer electrode) 60 Dielectrics 61 Expanded diameter part 63 Flange-shaped part 500 UV irradiation device 510 Excimer Lamp 520 Discharge container 521 Discharge tube 523 Large diameter section 530 Processing Container 540 Electrode (Inner Electrode) 550 Reflective Film (Outer Electrode) 560 Electrophores 561. Diameter section 563. Edge-like portion

Claims

1. A tubular discharge vessel that forms a discharge space, The system comprises an outer container that forms a flow path between itself and the discharge container, An excimer lamp characterized in that at least one end of the flow path along the lamp axis direction is formed closer to the center in the lamp axis direction than the end of the discharge vessel.

2. The excimer lamp according to claim 1, characterized in that at least one end of the flow path along the lamp axis direction is formed closer to the center in the lamp axis direction than the end of the cylindrical portion of the discharge vessel.

3. The excimer lamp according to claim 2, characterized in that the gap distance between the flow channels is constant along the lamp axis in the cylindrical portion of the discharge vessel.

4. The excimer lamp according to claim 3, characterized in that the gap distance along the lamp radial direction of the flow path is less than or equal to the thickness of the outer container.

5. The excimer lamp according to claim 4, characterized in that the gap distance along the lamp radial direction of the flow path is set to a range of 0.2 mm or more and 2 mm or less.

6. The discharge container comprises a pair of electrodes provided inside and outside the outer container, The excimer lamp according to claim 5, characterized in that at least one end of the flow path is formed on the lamp axial end side of the range where the pair of electrodes face each other.

7. The discharge vessel is provided with an inner electrode, The excimer lamp according to claim 6, characterized in that at least one end of the flow path is formed on the lamp axial end side than the end of the inner electrode.

8. The excimer lamp according to claim 7, characterized in that the other end of the flow path extends beyond the end of the cylindrical portion of the discharge vessel and across to the lamp axial end.

9. The excimer lamp according to claim 8, characterized in that the length of the flow path along the lamp axis direction is longer than the length of the cylindrical portion along the lamp axis direction.

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