UV irradiation device

Abstract

To improve startability in an ultraviolet light irradiation device in which an excimer lamp is used as an ultraviolet light source.SOLUTION: An ultraviolet light irradiation device has an excimer lamp having a discharge container including a discharge gas sealed therein, first and second electrodes arranged separately to each other in the longitudinal direction of the discharge container and in contact with the outer surface of the discharge container, a starting auxiliary electrode connected to one of the first and second electrodes and extending toward the other electrode, and a dielectric body interposed between the starting auxiliary electrode and the other electrode.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to an ultraviolet irradiation device, and more particularly to an ultraviolet irradiation device that uses an excimer lamp as an ultraviolet light source. [Background technology]

[0002] Conventionally, excimer lamps have been known in which a pair of external electrodes are arranged facing each other on the outer surface of a discharge vessel, and it is known to provide a starting auxiliary electrode made of a conductive material on the inner surface of the discharge vessel in order to improve starting performance (for example, Patent Document 1 below).

[0003] In Patent Document 1, the external electrode is provided with a branched electrode consisting of a root portion extending from the end in the tube axis direction of the external electrode along the tube axis direction of the discharge vessel and a branch portion extending from the tip of the root portion in the width direction of the discharge vessel, and the starting auxiliary electrode is arranged so as to overlap the tip of the branch portion of the branched electrode of the external electrode with the discharge vessel interposed therebetween. With this configuration, when starting the excimer lamp, a high-frequency current applied to one external electrode becomes a kind of capacitor-coupled state and flows to the other external electrode through the dielectric wall that makes up the discharge vessel, making it easier to generate a discharge and improving starting performance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-190676 Summary of the Invention [Problem to be solved by the invention]

[0005] In an excimer lamp 90 as shown in FIG. 26, electrode blocks (91, 92) are arranged in the longitudinal direction of the excimer lamp 90, the outer surface of the discharge vessel is brought into contact with the electrode blocks (91, 92), and a high voltage is applied between the electrode blocks (91, 92) to generate a discharge. If the above idea is applied to an excimer lamp 90 and a starting auxiliary electrode 93 is arranged on the inner surface of the discharge vessel, the discharge will be concentrated near the starting auxiliary electrode 93, reducing the efficiency of emitting ultraviolet light.

[0006] Furthermore, when rare gas and halogen gas are enclosed in the discharge vessel, the halogen gas is highly reactive and is absorbed by conductive materials, making it difficult to form a starting auxiliary electrode within the discharge vessel.

[0007] Furthermore, halogen gas has a large electron affinity, and excimer lamps in which halogen gas is sealed in the discharge vessel tend to be difficult to start, so improvements in starting ability are required.

[0008] In view of the above problems, an object of the present invention is to improve the startability of an ultraviolet irradiation device that uses an excimer lamp as an ultraviolet light source. [Means for solving the problem]

[0009] The ultraviolet irradiation device according to the present invention comprises: an excimer lamp having a discharge vessel in which a discharge gas is sealed; first and second electrode bodies arranged spaced apart in the longitudinal direction of the discharge vessel and in contact with the outer surface of the discharge vessel; a starting auxiliary electrode connected to one of the first and second electrode bodies and extending toward the other electrode body; and a dielectric interposed between the auxiliary starting electrode and the other electrode body.

[0010] According to this configuration, the excitation of excimer within the discharge vessel of the excimer lamp is induced by the light emission of atmospheric discharge by the starting auxiliary electrode, thereby improving the starting performance of the excimer lamp.

[0011] In this specification, "interposed between the starting auxiliary electrode and the other electrode body" simply means that the dielectric is present between them, and the dielectric may or may not be in contact with them. Specifically, the dielectric is present between the starting auxiliary electrode and the other electrode body, and may or may not be in contact with the starting auxiliary electrode and the other electrode body. Furthermore, another member may be present between the dielectric and the starting auxiliary electrode or the other electrode body.

[0012] In the ultraviolet irradiation device according to the present invention, a recess is formed in the first electrode body or the second electrode body, The dielectric may be held by the recess.

[0013] According to this configuration, the dielectric is held by the recess, which makes the device resistant to shocks and vibrations.

[0014] In the ultraviolet irradiation device according to the present invention, a plurality of the excimer lamps may be provided in a direction intersecting with the longitudinal direction, and the starting auxiliary electrode may be disposed between adjacent ones of the excimer lamps.

[0015] When one of the two excimer lamps sandwiched between the auxiliary starting electrode lights up, this triggers the other to light up as well, so it is sufficient to light either one of the excimer lamps, and by placing the auxiliary starting electrode between adjacent excimer lamps, the probability of the auxiliary starting electrode assisting lighting increases.

[0016] In the ultraviolet irradiation device according to the present invention, the dielectric may be tubular with one end closed, and may cover the tip of the starting assisting electrode.

[0017] This configuration makes it difficult for creeping discharge to occur on the surface of the dielectric.

[0018] In the ultraviolet irradiation device according to the present invention, the starting auxiliary electrode may be configured to have elasticity such that a tip portion thereof is pressed against the dielectric body.

[0019] According to this configuration, the dielectric is held by the starting auxiliary electrode, making it resistant to shocks and vibrations.

[0020] In the ultraviolet irradiation device according to the present invention, the dielectric may be in the form of a plate extending in the longitudinal direction of the discharge vessel and sandwiched on both sides by the starting auxiliary electrode and the other electrode body.

[0021] According to this configuration, the dielectric and the starting auxiliary electrode can be made simple in structure, and therefore are easy to manufacture.

[0022] In the ultraviolet irradiation device according to the present invention, the dielectric may be arranged across the first electrode body and the second electrode body.

[0023] According to this configuration, the dielectric is held by both the first and second electrode bodies, which makes it more resistant to shocks and vibrations.

[0024] In the ultraviolet irradiation device according to the present invention, the discharge gas may contain a halogen gas.

[0025] Excimer lamps filled with discharge gas containing halogen gas are difficult to start, so it is preferable to provide a starting auxiliary electrode to improve starting performance.

[0026] In the ultraviolet irradiation device according to the present invention, the discharge gas may be a mixed gas of Kr and Cl2.

[0027] When an excimer lamp is filled with a discharge gas that is a mixture of Kr and Cl2, the main emission wavelength of the ultraviolet light emitted from the excimer lamp is around 222 nm. Ultraviolet light in this wavelength range exhibits high sterilization performance, making it possible to realize an ultraviolet irradiation device that is particularly suitable for sterilization purposes. [Brief explanation of the drawings]

[0028] [Figure 1]1 is a diagram schematically illustrating one mode of use of the ultraviolet irradiation device of the present invention. [Figure 2] FIG. 1 is a perspective view schematically illustrating an example of the appearance of an ultraviolet irradiation device. [Figure 3] 3 is a perspective view showing the main body and cover of the casing disassembled from FIG. 2. FIG. [Figure 4] FIG. 4 is a schematic perspective view illustrating a plurality of excimer lamps and electrode bodies extracted from FIG. 3. [Figure 5] FIG. 2 is a schematic diagram for explaining the positional relationship between the excimer lamp and the electrode body, and is a schematic plan view of the excimer lamp as viewed in the +Z direction. [Figure 6] FIG. 2 is a perspective view of the electrode body as seen from the opposite side to the light extraction surface. [Figure 7] FIG. 2 is a plan view of the electrode body as viewed from the opposite side to the light extraction surface. [Figure 8] FIG. 10 is a plan view schematically showing an electrode body according to another embodiment. [Figure 9] FIG. 10 is a plan view schematically showing an electrode body according to another embodiment. [Figure 10] 10A and 10B are a plan view and a side view schematically showing an electrode body according to another embodiment. [Figure 11] 10A and 10B are a plan view and a side view schematically showing an electrode body according to another embodiment. [Figure 12] 10A and 10B are three-view diagrams schematically showing an electrode body according to another embodiment. [Figure 13] FIG. 10 is a plan view schematically showing an electrode body according to another embodiment. [Figure 14] 10A and 10B are a plan view and a cross-sectional view schematically showing an electrode body according to another embodiment. [Figure 15] 10A and 10B are a plan view and a side view schematically showing an electrode body according to another embodiment. [Figure 16] 10A and 10B are a plan view and a side view schematically showing an electrode body according to another embodiment. [Figure 17] 10A and 10B are a plan view and a side view schematically showing an electrode body according to another embodiment. [Figure 18]10A and 10B are a plan view and a side view schematically showing an electrode body according to another embodiment. [Figure 19] FIG. 10 is a plan view schematically showing an electrode body according to another embodiment. [Figure 20] 10A and 10B are a plan view and a side view schematically showing an electrode body according to another embodiment. [Figure 21] FIG. 10 is a plan view schematically showing an electrode body according to another embodiment. [Figure 22] 10A and 10B are diagrams schematically showing a starting auxiliary electrode and a dielectric according to another embodiment. [Figure 23] 10A and 10B are diagrams schematically showing a starting auxiliary electrode and a dielectric according to another embodiment. [Figure 24] 10A and 10B are diagrams schematically showing a starting auxiliary electrode and a dielectric according to another embodiment. [Figure 25] FIG. 10 is a plan view schematically showing an electrode assembly according to Comparative Example 2. [Figure 26] FIG. 10 is a plan view schematically showing an electrode assembly according to the prior art. DETAILED DESCRIPTION OF THE INVENTION

[0029] Each embodiment of the ultraviolet irradiation device according to the present invention will be described with reference to the drawings as appropriate. Note that the following drawings are schematic illustrations, and the dimensional ratios in the drawings do not necessarily match the actual dimensional ratios. Furthermore, the dimensional ratios between the drawings do not necessarily match.

[0030] Fig. 1 is a diagram schematically illustrating one embodiment of an ultraviolet irradiation device according to the present invention. Fig. 1 shows an ultraviolet irradiation device 1 mounted in a housing 100, and a state in which ultraviolet light L1 is irradiated onto an irradiation target area 40 from a light extraction surface 30 of the ultraviolet irradiation device 1.

[0031] Fig. 2 is a perspective view schematically showing an example of the appearance of the ultraviolet irradiation device 1. Fig. 3 is a perspective view in which the main body 2a and the lid 2b of the casing 2 of the ultraviolet irradiation device 1 are disassembled from Fig. 2.

[0032] In the following drawings, the explanation will be made with reference to an XYZ coordinate system in which the direction in which ultraviolet light L1 is extracted is the X direction and the plane perpendicular to the X direction is the YZ plane. More specifically, as will be described later with reference to Figure 2 and subsequent drawings, the tube axis direction of the excimer lamp 10 is the Y direction, and the direction perpendicular to the X and Y directions is the Z direction.

[0033] In the following description, when a positive or negative direction is to be distinguished when expressing a direction, the direction is described with a positive or negative sign, such as "+X direction" and "-X direction." When a direction is to be expressed without distinguishing between positive and negative directions, the direction is simply described as "X direction." In other words, in this specification, when simply referring to the "X direction," both the "+X direction" and the "-X direction" are included. The same applies to the Y direction and the Z direction.

[0034] 2 and 3, the ultraviolet irradiation device 1 includes a casing 2 having a light extraction surface 30 formed on one surface. The casing 2 includes a main body 2a and a lid 2b, and the main body 2a accommodates a plurality of excimer lamps 10 and electrode bodies (21, 22). In this embodiment, four excimer lamps 10 are accommodated in the casing 2. The electrode bodies (21, 22) may be in a form that allows current to be applied to the excimer lamps 10, and may be in the form of, for example, a block, plate, mesh, or the like, so as to be in contact with the discharge vessel 11 of the excimer lamp 10.

[0035] Fig. 4 is a perspective view illustrating a plurality of excimer lamps 10 and electrode bodies (21, 22) extracted from Fig. 3. Fig. 5 is a side view schematically illustrating the positional relationship between the excimer lamps 10 and the electrode bodies (21, 22).

[0036] 4, the ultraviolet irradiation device 1 of this embodiment includes four excimer lamps 10 arranged at a distance in the Z direction. Two electrode bodies (21, 22) are arranged so as to contact a portion of the outer surface of each excimer lamp 10. Hereinafter, the electrode body 21 may be referred to as the first electrode body 21, and the electrode body 22 may be referred to as the second electrode body 22.

[0037] Each excimer lamp 10 has a discharge vessel 11 whose tube axis direction is in the Y direction, and at positions spaced apart in the Y direction, parts of the outer surface of the discharge vessel 11 of the excimer lamp 10 are in contact with each electrode body (21, 22). In other words, each electrode body (21, 22) is in contact with the outer surface of the discharge vessel 11 of each excimer lamp 10 and is arranged so as to straddle each excimer lamp 10 in the Z direction.

[0038] As described above, the ultraviolet irradiation device 1 in this embodiment includes a pair of electrode bodies (21, 22) that are spaced apart from each other in the Y direction. The electrode bodies (21, 22) are made of a conductive material, and preferably made of a material that is reflective to ultraviolet light emitted from the excimer lamp 10. As an example, the electrode bodies (21, 22) are made of Al, an Al alloy, stainless steel, or the like.

[0039] When a high-frequency AC voltage, for example, of about 1 kHz to 5 MHz, is applied between the electrode bodies (21, 22), the voltage is applied to the discharge gas 10G sealed inside each excimer lamp 10 via the discharge vessel 11 of each excimer lamp 10. The gas species of the discharge gas 10G may be any material that, when such a voltage is applied, excimer light is emitted when the atoms constituting the gas species are excited or ionized to an excimer state and then transition to the ground state. More specifically, the discharge gas 10G may be one or more rare gases such as argon (Ar), krypton (Kr), or xenon (Xe), or may be a mixed gas of the rare gas with a halogen gas such as fluorine (F), chlorine (Cl), iodine (I), or bromine (Br).

[0040] As an example, the discharge gas 10G can be a mixture of krypton (Kr), chlorine (Cl), and argon (Ar). In this case, krypton and chlorine function as luminous gases, and argon functions as a buffer gas. The buffer gas can be one or more rare gases selected from argon (Ar), neon (Ne), and helium (He).

[0041] Excimer lamp 10, which uses a mixture of Kr and Cl2 as discharge gas 10G, emits ultraviolet light with a peak wavelength of approximately 222 nm. Even if ultraviolet light in the wavelength range of 190 nm or more and 235 nm or less, including 222 nm, is irradiated onto human skin, it is absorbed by the stratum corneum and does not penetrate further inward (toward the basal layer). Because the keratinocytes contained in the stratum corneum are dead cells, there is virtually no risk of DNA damage caused by absorption by living cells in the spinous layer, granular layer, or dermis, as occurs with irradiation of ultraviolet light with a wavelength of 254 nm.

[0042] It is known that ultraviolet rays in the above wavelength band have a sterilizing effect on the object to be irradiated. Therefore, ultraviolet irradiation devices equipped with excimer lamps containing discharge gas as described above are expected to be used in a variety of applications, including photosterilization, and are expected to be used in a wide range of situations.

[0043] Fig. 6 is a perspective view of the block-shaped electrode body (21, 22) as seen from the side opposite to the light extraction surface 30. Fig. 7 is a plan view of the electrode body (21, 22) as seen from the side opposite to the light extraction surface 30. In Fig. 7, a dielectric 6, which will be described later, is shown in cross section.

[0044] The electrode bodies (21, 22) have the same shape. A first recess 23 and a second recess 24 are formed on the -X side surfaces of the electrode bodies (21, 22). The first recess 23 extends in the -Y direction from the +Y side surface of the electrode bodies (21, 22). The second recess 24 extends in the +Y direction from the -Y side surface of the electrode bodies (21, 22). The first recess 23 and the second recess 24 are arranged to face each other in the Y direction. The first recess 23 and the second recess 24 are formed in the center of the electrode bodies (21, 22) in the Z direction.

[0045] Furthermore, screw holes 25 for connecting a power supply line 7 (see FIG. 2) are formed on the −X side surfaces of the electrode bodies (21, 22). A high-voltage power supply line 7 is connected to the screw hole 25 of the first electrode body 21, and a low-voltage power supply line 7 is connected to the screw hole 25 of the second electrode body 22. However, it is also possible that the low-voltage power supply line 7 is connected to the screw hole 25 of the first electrode body 21, and the high-voltage power supply line 7 is connected to the screw hole 25 of the second electrode body 22.

[0046] Furthermore, third recesses 26 that come into contact with the outer surface of the discharge vessel 11 of the excimer lamp 10 are formed on the +X side surfaces of the electrode bodies (21, 22). Four third recesses 26 are provided at equal intervals in the Z direction. The first recess 23 and the second recess 24 are disposed between the two central third recesses 26.

[0047] The ultraviolet irradiation device 1 of this embodiment is equipped with a starting auxiliary electrode 5. The starting auxiliary electrode 5 is installed to assist in starting the excimer lamp 10. The starting auxiliary electrode 5 is connected to the first electrode body 21 and extends toward the second electrode body 22. The starting auxiliary electrode 5 of this embodiment extends in the Y direction.

[0048] The starting auxiliary electrode 5 of this embodiment is composed of a spring-like proximal portion 5a and a rod-like distal portion 5b, and is elastic as a whole. The proximal portion 5a is electrically connected to the first electrode body 21. The proximal portion 5a is disposed in the first recess 23 of the first electrode body 21, and is in contact with the inner wall 23a on the -Y side of the first recess 23. The proximal portion 5a is pressed against the inner wall 23a of the first recess 23 by its own elastic force.

[0049] Although the starting auxiliary electrode 5 of this embodiment is configured with a spring-shaped proximal portion 5a and a rod-shaped distal portion 5b, the shape of the starting auxiliary electrode 5 is not limited to this. The shape of the starting auxiliary electrode 5 as a whole may be columnar, rod-shaped, thin plate-shaped, or the like. The shape of the distal portion 5b of the starting auxiliary electrode 5 is also not limited to a rod shape and may be a thin plate-shaped, or the like, but it is preferable that the tip 5c of the distal portion 5b be pointed. This concentrates the electric field at the tip 5c of the starting auxiliary electrode 5, making it easier to discharge at the tip 5c of the starting auxiliary electrode 5.

[0050] The starting assist electrode 5 is made of a conductive material, such as aluminum, stainless steel, molybdenum, or tungsten.

[0051] A dielectric 6 is interposed between the starting auxiliary electrode 5 and the second electrode body 22. The dielectric 6 in this embodiment has a cylindrical shape with one end closed. More specifically, the dielectric 6 has a bottomed cylindrical shape having a cylindrical portion 6a and a bottom portion 6b that closes one end of the cylindrical portion 6a. The cylindrical portion 6a is not limited to a cylindrical shape and may be a rectangular cylindrical shape, etc. The bottom portion 6b is not limited to a flat shape and may be a hemispherical shape, etc.

[0052] The dielectric 6 is held by the first recess 23 of the first electrode body 21 and the second recess 24 of the second electrode body 22. The cylindrical portion 6a of the dielectric 6 is slightly smaller than the first recess 23, and the bottom portion 6b is slightly smaller than the second recess 24.

[0053] The dielectric 6 is disposed so as to cover the tip 5c of the auxiliary starting electrode 5. The tip 5c of the auxiliary starting electrode 5 is pressed against the bottom 6b of the dielectric 6 by the elastic force of the proximal portion 5a.

[0054] The dielectric 6 is preferably made of a material that has high insulating properties, high mechanical strength, and high ultraviolet transmittance. For example, the dielectric 6 is made of quartz glass, ceramics such as alumina, or resin such as PTFE.

[0055] When the ultraviolet irradiation device 1 is operated, a high-frequency voltage is applied between the electrode bodies (21, 22) as described above from a power source (not shown) via the power line 7 (see FIG. 2). As a result, the high-frequency voltage is applied to the discharge gas 10G sealed in each excimer lamp 10 via the discharge vessel 11.

[0056] In excimer lamp 10, a high-frequency voltage is applied between the electrodes (21, 22), and the insulation in the discharge space (inside discharge vessel 11) is broken down, causing excimer light to be emitted. When the insulation is broken down, discharge begins and ends repeatedly on the order of nanoseconds, and by performing this at a high frequency, the lamp appears to be lit continuously.

[0057] Incidentally, when halogen gas is enclosed in excimer lamp 10, the high electron affinity of the halogen gas causes it to adsorb electrons, making it difficult for current to flow (electrons to move) unless the lamp is continuously lit. Therefore, in order to improve the starting performance of excimer lamp 10, it is necessary to irradiate the discharge space with light of a wavelength having energy close to the excitation energy of excimer emission, which induces excitation of the excimer in the discharge space (making it easier to discharge).

[0058] In the ultraviolet irradiation device 1 of this embodiment, a voltage is applied between the electrode bodies (21, 22), and a voltage is also applied between the starting auxiliary electrode 5 connected to the first electrode body 21 and the second electrode body 22. At this time, because the distance between the starting auxiliary electrode 5 and the second electrode body 22 is shorter than the distance between the first electrode body 21 and the second electrode body 22, a dielectric breakdown occurs first at a lower voltage in the space between the starting auxiliary electrode 5 and the second electrode body 22, causing a dielectric barrier discharge in the atmosphere. As a result, ultraviolet rays are emitted from the tip 5c of the starting auxiliary electrode 5. The wavelength band of the ultraviolet rays at this time includes 226 to 227 nm.

[0059] The light emitted by the atmospheric discharge from the starting auxiliary electrode 5 induces excitation of excimers in the discharge space of the excimer lamp 10 (causing discharge). Therefore, when ultraviolet light is incident from the starting auxiliary electrode 5 while a voltage is applied to the discharge gas 10G through the electrode bodies (21, 22), the excimer lamp 10 is lit in a short time (for example, within 0 to 2 seconds) using this light energy as a trigger. When the discharge gas 10G contains krypton (Kr) and chlorine (Cl), the light emitted from the excimer lamp 10 is ultraviolet light with a peak wavelength of 222 nm.

[0060] After the excimer lamp 10 is lit, the starting auxiliary electrode 5 also continues to light, but because it uses very little power, it does not affect the illuminance of the excimer lamp 10. Furthermore, after the excimer lamp 10 is lit, the discharge inside the lamp becomes dominant, which acts to suppress atmospheric discharge at the starting auxiliary electrode 5, further reducing the impact.

[0061] Another feature of the starting auxiliary electrode 5 is that after the excimer lamp 10 is lit, the voltage is distributed to the excimer lamp 10 as well, so the voltage applied to the starting auxiliary electrode 5 is lower than at the time of starting, and the load on the starting auxiliary electrode 5 is reduced during continuous lighting, resulting in a long life as a trigger.

[0062] Although the embodiments of the present invention have been described above with reference to the drawings, the specific configurations should not be considered to be limited to these embodiments. The scope of the present invention is defined not only by the description of the above embodiments but also by the claims, and further includes all modifications within the meaning and scope of the claims.

[0063] The structures employed in the above-described embodiments can be employed in any other embodiment. The specific configurations of the components are not limited to the above-described embodiments, and various modifications are possible within the scope of the present invention.

[0064] [Another embodiment] (1) The combination of the starting auxiliary electrode 5 and the dielectric 6 is not limited to the above configuration. FIG. 8 is a plan view schematically showing an electrode body (21, 22) according to another embodiment. In this example, the starting auxiliary electrode 5 is rod-shaped with a pointed tip. The dielectric 6 is plate-shaped and parallel to the XZ plane. The starting auxiliary electrode 5 and the dielectric 6 do not necessarily need to be in contact with each other, and may be spaced apart enough to allow discharge.

[0065] (2) Fig. 9 is a plan view schematically showing electrode bodies (21, 22) according to another embodiment. In this example, the starting auxiliary electrode 5 is rod-shaped with a pointed tip. The dielectric 6 is cylindrical with a bottom. However, in this example, unlike the example shown in Fig. 7, the dielectric 6 is held only by the second electrode body 22.

[0066] (3) Fig. 10 is a plan view and a side view schematically showing electrode bodies (21, 22) according to another embodiment. In this example, the starting auxiliary electrode 5 is electrically connected to the first electrode body 21 and has a generally rod-like shape extending toward the second electrode body 22. A proximal portion of the starting auxiliary electrode 5 extends toward and is connected to the first electrode body 21. The dielectric 6 has a cylindrical shape with a bottom and is placed on the surfaces of the first electrode body 21 and the second electrode body 22.

[0067] (4) Fig. 11 is a plan view and a side view schematically showing electrode bodies (21, 22) according to another embodiment. In this example, the starting auxiliary electrode 5 is U-shaped in side view, and a portion of it is in contact with the first electrode body 21. The dielectric 6 is a plate-like member extending in the Y direction, and is sandwiched between the U-shaped starting auxiliary electrodes 5. The dielectric 6 is also sandwiched on both sides between the starting auxiliary electrodes 5 and the second electrode body 22.

[0068] (5) Fig. 12 is a three-view diagram schematically illustrating an electrode assembly (21, 22) according to another embodiment. In this example, the same starting auxiliary electrode 5 as that shown in Fig. 11 is connected to the +X side surface of the first electrode assembly 21.

[0069] (6) Fig. 13 is a plan view schematically illustrating an electrode assembly (21, 22) according to another embodiment. In this example, the starting auxiliary electrode 5 and the dielectric 6, which are the same as those shown in Fig. 11, are arranged on the side surfaces of the electrode assembly (21, 22) in the Z direction.

[0070] (7) Fig. 14 is a plan view and a cross-sectional view schematically illustrating an electrode body (21, 22) according to another embodiment. In this example, as shown in the cross-sectional view of Fig. 14, a starting auxiliary electrode 5 and a dielectric 6 are sandwiched between the excimer lamp 10 and the electrode body (21, 22). The starting auxiliary electrode 5 may be in the form of a coil spring. The dielectric 6 may be in the form of a cylinder with a bottom.

[0071] (8) Fig. 15 is a plan view and a side view schematically illustrating electrode assemblies (21, 22) according to another embodiment. In the above embodiment, the starting auxiliary electrode 5 is described as an independent member, but this is not limiting. As shown in Fig. 15, the starting auxiliary electrode 5 may be configured integrally with the first electrode assembly 21.

[0072] (9) Figure 16 is a plan view and a side view schematically showing electrode bodies (21, 22) according to another embodiment. In this example, the starting auxiliary electrode 5 is also integrally formed with the first electrode body 21. The starting auxiliary electrode 5 is formed to protrude from the +Y side surface of the first electrode body 21.

[0073] (10) Figure 17 is a plan view and a side view schematically showing electrode bodies (21, 22) according to another embodiment. In this example, the dielectric body 6 has a cylindrical shape with both ends open.

[0074] (11) Figure 18 is a plan view and a side view showing electrode bodies (21, 22) according to another embodiment. In this example, the dielectric body 6 also has a cylindrical shape with both ends open.

[0075] (12) Fig. 19 is a plan view schematically showing electrode assemblies (21, 22) according to another embodiment. In this example, two auxiliary starting electrodes 5 are provided. That is, a first auxiliary starting electrode 51 is connected to the first electrode assembly 21 and extends toward the second electrode assembly 22, and a second auxiliary starting electrode 52 is connected to the second electrode assembly 22 and extends toward the first electrode assembly 21. A dielectric 6 is interposed between the first auxiliary starting electrode 51 and the second electrode assembly 22, and between the second auxiliary starting electrode 52 and the first electrode assembly 21.

[0076] (13) FIG. 20 is a side view schematically illustrating electrode assemblies (21, 22) according to another embodiment. In this example, two auxiliary starting electrodes 5 are provided. That is, a first auxiliary starting electrode 51 is connected to the first electrode assembly 21 and extends toward the second electrode assembly 22, and a second auxiliary starting electrode 52 is connected to the second electrode assembly 22 and extends toward the first electrode assembly 21. A dielectric 6 is interposed between the first auxiliary starting electrode 51 and the second electrode assembly 22, and also between the first auxiliary starting electrode 51 and the second auxiliary starting electrode 52. Here, at least a portion of the first auxiliary starting electrode 51 is housed in the cylindrical dielectric 6. Furthermore, it is desirable that at least one of the first auxiliary starting electrode 51 and the second auxiliary starting electrode 52 has a tip end 51c, 52c of the auxiliary starting electrode between the first electrode assembly 21 and the second electrode assembly 22. In addition, multiple dielectrics 6 may be used so that they are interposed between the first auxiliary starting electrode 51 and the second electrode body 22, and between the first auxiliary starting electrode 51 and the second auxiliary starting electrode 52, respectively.

[0077] (14) Fig. 21 is a plan view schematically showing electrode bodies (21, 22) according to another embodiment. In this example, the dielectric body 6 has a cylindrical shape with a bottom. The auxiliary starting electrode 5 is connected to the first electrode body 21 and extends toward the second electrode body 22. The tip of the auxiliary starting electrode 5 is pressed against the bottom of the dielectric body 6. The auxiliary starting coil 53 connected to the second electrode body 22 is wound around the bottom side of the dielectric body 6.

[0078] (15) Figure 22 is a diagram showing a starting assist electrode 5 and a dielectric 6 according to another embodiment. In this example, the starting assist electrode 5 is composed of a spring-like proximal portion 5a and a spring-like distal portion 5b. The starting assist electrode 5 is composed of a single coil spring, and the pitch of the distal portion 5b is wider than the pitch of the proximal portion 5a.

[0079] (16) Fig. 23 is a diagram schematically illustrating a starting auxiliary electrode 5 and a dielectric 6 according to another embodiment. In this example, the starting auxiliary electrode 5 is composed of a spring-shaped proximal portion 5a and a rod-shaped distal portion 5b, similar to the example shown in Fig. 7. Meanwhile, the dielectric 6, unlike the example shown in Fig. 7, has a cylindrical shape with both ends closed. It is preferable that the interior of the dielectric 6 is filled with, for example, an inert gas mixed with nitrogen. Furthermore, from the viewpoint of further improving starting performance, it is preferable that the interior of the dielectric 6 be under negative pressure.

[0080] (17) Fig. 24 is a diagram schematically illustrating a starting auxiliary electrode 5 and a dielectric 6 according to another embodiment. In this example, the dielectric 6 has no internal space and is in close contact with the distal portion 5b of the starting auxiliary electrode 5.

[0081] (18) Furthermore, it is desirable that the tip of the starting auxiliary electrode 5 according to the present invention is positioned so that it faces the discharge vessel 11 of the excimer lamp 10. This allows the ultraviolet rays generated at the tip of the starting auxiliary electrode 5 to easily reach the discharge space within the excimer lamp 10 without being blocked, making it easier to induce excitation of excimers in the discharge space (easier discharge). [Example]

[0082] Examples that specifically illustrate the configuration and effects of the present invention will be described below. An ultraviolet irradiation device with the following specifications was fabricated as an example. The starting auxiliary electrode 5 and the dielectric 6 had the configuration shown in Figure 9.

[0083] [Discharge vessel] Material: Quartz glass, Outer diameter: 6 mm, Total length: 60 mm [Discharge gas] Gas pressure: 20 kPa, Gas type: Cl, Kr mixed gas [Electrode body] Material: Aluminum Length = 60 mm, distance between electrodes = 6 mm [inverter] Voltage: 5kV, Frequency: 100kHz [Starting aid electrode] Material: Aluminum Width = 1.5 mm, thickness = 0.1 mm, length = 25 mm [Dielectric] Outer diameter = 3 mm, inner diameter = 1.6 mm, length = 5 mm

[0084] Comparative Example 1 was the ultraviolet irradiation device described above, but without the auxiliary starting electrode and dielectric. Comparative Example 2 was the ultraviolet irradiation device described above, but without the auxiliary starting electrode and dielectric, but with an LED 8 as an auxiliary starting light source, as shown in Fig. 25. The LED 8 emits ultraviolet light with a wavelength of 275 nm.

[0085] For the Examples, a starting ability test was conducted on the excimer lamps that had been lit for 8,500 hours by applying a voltage between the electrodes under the inverter conditions described above. The starting ability test was conducted 10 times for each Example, and the average time (starting delay time) from when the voltage was applied until the excimer lamp lit up was evaluated. The results for the Examples are shown in Table 1, and the results for Comparative Example 2 are shown in Table 2. In Table 1, cases where the excimer lamp lit up within 1 second were recorded as 0 seconds.

[0086] [Table 1]

[0087] [Table 2]

[0088] In the examples, the average start-up delay time was 1.1 seconds, as shown in Table 1. In Comparative Example 1, the excimer lamp did not light even after 60 seconds. In Comparative Example 2, the average start-up delay time was 45.9 seconds, as shown in Table 2. In other words, the ultraviolet irradiation device of the present invention was able to greatly improve start-up performance. [Explanation of symbols]

[0089] 1: Ultraviolet irradiation device 5: Starting auxiliary electrode 5a: Proximal part 5b: distal part 5c:Tip 6: Dielectric 6a:Cylinder part 6b: Bottom 7: Power line 8: LED 10: Excimer lamp 10G: Discharge gas 11: Discharge vessel 21: First electrode body 22: Second electrode body 23: First recess 23a: Inner wall of first recess 24: Second recess 26: Third recess 30: Light extraction surface 40: Irradiation target area 51: First starting auxiliary electrode 52: Second starting auxiliary electrode 53: Starting auxiliary coil 100: Housing

Claims

1. an excimer lamp having a discharge vessel in which a discharge gas is sealed; first and second electrode bodies arranged spaced apart in the longitudinal direction of the discharge vessel and in contact with an outer surface of the discharge vessel; a starting auxiliary electrode connected to one of the first and second electrode bodies and extending toward the other electrode body; and a dielectric interposed between the starting auxiliary electrode and the other electrode body.

2. A recess is formed in the first electrode body or the second electrode body, The ultraviolet irradiation device according to claim 1 , wherein the dielectric body is held by the recess.

3. The excimer lamps are provided in a plurality of positions in a direction intersecting the longitudinal direction, 2. The ultraviolet irradiation device according to claim 1, wherein the starting auxiliary electrode is disposed between adjacent ones of the excimer lamps.

4. 4. The ultraviolet irradiation device according to claim 1, wherein the dielectric body has a cylindrical shape with one end closed and covers a tip end of the starting auxiliary electrode.

5. 4. The ultraviolet irradiation device according to claim 1, wherein the starting auxiliary electrode has elasticity such that a tip portion thereof is pressed against the dielectric body.

6. 4. The ultraviolet irradiation device according to claim 1, wherein the dielectric is plate-shaped extending in the longitudinal direction of the discharge vessel and is sandwiched on both sides between the starting auxiliary electrode and the other electrode body.

7. 4. The ultraviolet irradiation device according to claim 1, wherein the dielectric body is disposed across the first electrode body and the second electrode body.

8. 4. The ultraviolet irradiation device according to claim 1, wherein the discharge gas contains a halogen gas.

9. The discharge gas is Kr and Cl 2 4. The ultraviolet irradiation device according to claim 1, wherein the mixed gas is a gas mixture of the above.

Images