Ultraviolet irradiation device

Abstract

The invention provides an ultraviolet irradiation device capable of maintaining high startability. The ultraviolet irradiation device comprises: a lamp container in which a discharge gas for generating excimer light is sealed; a pair of lamp electrodes which are disposed so as not to be exposed to the discharge gas and which apply a voltage to the lamp container; a start-up electrode which is disposed so as to face a site having the same potential as one of the pair of lamp electrodes and having the same potential as the other electrode, and which discharges and generates trigger light; a start-up discharge vessel surrounding the tip of the start-up electrode and transmitting the trigger light; and a sealing part which hermetically seals a space including at least the space inside the start discharge container, the sealing part being made of a material different from that of the start discharge container.

Description

Technical Field

[0001] The invention relates to an ultraviolet light irradiation device. Background Art

[0002] In an excimer lamp having a pair of external electrodes arranged on the outer surface of a lamp vessel, it is known to provide a starting electrode in order to improve the starting property of lighting (hereinafter simply referred to as “starting property”).

[0003] For example, Patent Document 1 describes providing a starting electrode electrically connected to one of the first and second electrodes for applying a voltage to the lamp vessel, and arranged opposite the other electrode or a conductor electrically connected to the other electrode via a dielectric to generate trigger light by causing a localized discharge. Furthermore, the document describes arranging a discharge vessel so as to surround the tip of the starting electrode and the localized discharge region.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2022-164223 Summary of the Invention

[0007] Technical problem to be solved by the invention

[0008] The market demands a longer life for ultraviolet irradiation devices. To achieve this, it is necessary to maintain high start-up performance over a long period of time. Therefore, an object of the present invention is to provide an ultraviolet irradiation device that maintains high start-up performance.

[0009] Technical solutions to technical problems

[0010] The ultraviolet irradiation device of the present invention comprises:

[0011] A lamp container encloses a discharge gas for generating excimer light;

[0012] a pair of lamp electrodes arranged so as not to be exposed to the discharge gas and for applying a voltage to the lamp container;

[0013] a starting electrode having the same potential as one of the pair of lamp electrodes and facing a portion having the same potential as the other electrode, thereby discharging to generate trigger light;

[0014] a starting discharge container, surrounding the front end of the starting electrode and allowing the trigger light to pass through; and

[0015] a sealing portion for hermetically sealing at least the space within the starting discharge container;

[0016] The sealing portion is made of a material different from that of the starting discharge container.

[0017] In the ultraviolet light irradiation device, the fact that the starting electrode and either of the pair of lamp electrodes are at the same potential indicates that the starting electrode is electrically connected to the one electrode. Furthermore, the portion at the same potential as the other electrode may be located on the surface of the other electrode or on the surface of a component electrically connected to the other electrode.

[0018] The details are described in the "Specific Implementation Methods". Here, the process and effects of completing the present invention are briefly described. Figure 14 This is a diagram showing the periphery of a lamp electrode of a conventional ultraviolet irradiation device. Patent document 1 also shows the same Figure 14 Same figure. A first electrode 9a and a second electrode 9b, which constitute the lamp electrodes, are fixed to the inner surface of a frame (not shown) of the ultraviolet irradiation device via respective threaded holes 9h. A starting electrode 5 is disposed in the recess of the first electrode 9a. The tip of the starting electrode 5 is covered by a discharge container 6 that surrounds the tip of the starting electrode 5 and forms a discharge space therein (hereinafter referred to as the "starting discharge container"), which surrounds the tip of the starting electrode 5 and forms a discharge space therein. A gap exists between the recess of the first electrode 9a and the starting discharge container 6, communicating with the exterior of the first electrode 9a. Therefore, the atmosphere outside the first electrode 9a flows into the interior of the starting discharge container 6 along the flow indicated by the arrow labeled F1.

[0019] The inventors have conducted in-depth research and found that when long-term use of Figure 14 When the lamp electrodes (9a, 9b), the starting electrode 5, and the starting discharge container 6 of the structure shown are irradiated with ultraviolet light, the connection between the starting electrode 5 and the component connected to the starting electrode 5 may corrode, thereby deteriorating the conductivity from the component to the starting electrode 5. The cause of the corrosion of the connection was investigated and it was found that the cause was oxidizing substances generated by the discharge generated at the tip of the starting electrode. It was found that the oxidizing substances were generated by nitrogen and water vapor contained in the atmosphere that entered along the flow indicated by the arrow marked F1.

[0020] Therefore, in the present invention, the space including the space within the starting discharge vessel is hermetically sealed. For example, the space encompassing at least the interior space of the starting discharge vessel and surrounded by the first electrode is hermetically sealed. The component used to hermetically seal this space is referred to herein as a sealing portion. By using the sealing portion, the space including the interior of the starting discharge vessel is hermetically sealed, preventing atmospheric air, which serves as a source of oxidizing substances, from flowing into this space. This suppresses the generation of oxidizing substances within the hermetically sealed space. Consequently, corrosion at the connection between the starting electrode and the conductor connected to the starting electrode is suppressed, maintaining electrical continuity from the conductor to the starting electrode 5. This allows the ultraviolet light irradiation device to emit stable trigger light even during prolonged use. Furthermore, even if oxidizing substances are generated within the starting discharge vessel, they are prevented from leaking outside the starting discharge vessel.

[0021] The sealing portion is made of a different material than the starting discharge container. For example, while the starting discharge container is required to allow the trigger light to pass through, the sealing portion is not required to allow the trigger light to pass through. Instead, it is required to provide an airtight seal to prevent gas from flowing through the container. Since the required properties of the starting discharge container differ from those of the sealing portion, a material that better matches the required properties of the sealing portion can be used for the sealing portion.

[0022] The sealing portion may hermetically seal only the space within the starting discharge vessel. If only the space within the starting discharge vessel is hermetically sealed, the sealing portion may be configured to cover the opening of the starting discharge vessel, or to block the gap between the opening of the starting discharge vessel and another component covering the opening. When the sealing portion is configured to cover the opening of the starting discharge vessel, the starting electrode may also penetrate the sealing portion. Furthermore, the sealing portion may hermetically seal not only the space within the starting discharge vessel but also the space extending outside the starting discharge vessel. For example, by blocking the gap between the starting discharge vessel and the recess that houses the lamp electrode of the starting discharge vessel, the sealing portion can hermetically seal the space extending inside and outside the starting discharge vessel.

[0023] A portion of the starting discharge vessel may be located between the starting electrode and a portion of the lamp electrode at the same potential as the other electrode. First to fifth embodiments have been disclosed as embodiments of the starting discharge vessel having such a positional relationship. A sixth embodiment discloses an embodiment in which a portion of the starting discharge vessel is not located between the starting electrode and the portion.

[0024] The sealing portion may also be made of a material having a hygroscopic effect, which absorbs water vapor in the starting discharge container to reduce the generation of oxidizing substances in the starting discharge container.

[0025] The sealing portion may be formed of an epoxy or silicone adhesive.

[0026] An atmospheric component containing at least nitrogen may be present inside the starting discharge container. Thus, a starting discharge can be generated while the atmospheric component is present, and trigger light can be generated by the atmospheric discharge.

[0027] The discharge gas may also contain Kr and Cl₂. When a discharge gas containing a mixture of Kr and Cl₂ is enclosed in an excimer lamp, the primary wavelength of ultraviolet light emitted from the excimer lamp is around 222 nm. Ultraviolet light in this wavelength range minimizes its impact on the human body while exhibiting high bactericidal and viral inactivation properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a perspective view showing the appearance of one embodiment of the ultraviolet irradiation device.

[0029] Figure 2 It is a perspective view showing the appearance of one embodiment of the ultraviolet irradiation device.

[0030] Figure 3 This is a perspective view showing the lamp vessel, lamp electrodes, starting electrode, and starting discharge vessel extracted from the ultraviolet irradiation device.

[0031] Figure 4 This is a partial enlarged view of the vicinity of the starting electrode observed along the +X direction.

[0032] Figure 5 It is the spectrum of the trigger light produced by atmospheric discharge.

[0033] Figure 6 It is a partial enlarged view showing a comparative embodiment in which the sealing portion of the starting discharge container is not sealed.

[0034] Figure 7 It is a diagram showing a modified example of the sealing portion.

[0035] Figure 8 It is a partially enlarged view of the second embodiment of the ultraviolet irradiation device.

[0036] Figure 9 It is a partially enlarged view of the third embodiment of the ultraviolet irradiation device.

[0037] Figure 10 It is a diagram showing a fourth embodiment of the ultraviolet irradiation device.

[0038] Figure 11 It is a diagram showing a fifth embodiment of the ultraviolet irradiation device.

[0039] Figure 12 It is a partially enlarged view of the sixth embodiment of the ultraviolet irradiation device.

[0040] Figure 13 Observed along the -X direction Figure 12 Part of the diagram.

[0041] Figure 14 This is a perspective view showing the extracted lamp electrodes, starting electrodes, and starting discharge container of a known ultraviolet irradiation device. DETAILED DESCRIPTION

[0042] The various embodiments of the ultraviolet irradiation device of the present invention will be described with reference to the accompanying drawings. The following drawings are schematic diagrams, and the dimensional ratios on the drawings may not necessarily be consistent with the actual dimensional ratios. Furthermore, the dimensional ratios between the drawings may not necessarily be consistent.

[0043] Below, each drawing is described with appropriate reference to the XYZ coordinate system. In the XYZ coordinate system, the direction of travel of the light on the optical axis of the radiated ultraviolet light is set to the +X direction, and the plane perpendicular to the X direction is set to the YZ plane. In addition, in this specification, when expressing a direction, when distinguishing between positive and negative directions, it is recorded by marking positive and negative signs such as "+X direction" and "-X direction". When expressing a direction without distinguishing between positive and negative directions, it is only recorded as "X direction". That is, in this specification, when it is only recorded as "X direction", both "+X direction" and "-X direction" are included. This also applies to the Y direction and the Z direction.

[0044] <First embodiment>

[0045] [Overview of UV irradiation device]

[0046] Figure 1 and Figure 2 Each of them is a perspective view showing the appearance of an embodiment of the ultraviolet irradiation device of the present invention. Figure 1 This is a diagram viewed from the light extraction portion 4 side of the ultraviolet irradiation device 10. Figure 2 This is a diagram viewed from the side opposite to the light extraction portion 4 side.

[0047] The ultraviolet irradiation device 10 of this embodiment includes an excimer lamp that radiates ultraviolet light. The ultraviolet irradiation device 10 includes a lamp container 3 (see Figure 2 ), a frame 2 for housing the lamp vessel 3, and a light extraction portion 4 for extracting the ultraviolet light emitted from the lamp vessel 3 to the outside of the frame 2 in the +X direction. Figure 1 and Figure 2 In FIG. 1 , the arrow L1 indicates the optical axis of the ultraviolet light emitted from the light extraction portion 4 and the traveling direction of the light on the optical axis. The longitudinal direction of the tube axis of the lamp vessel 3 extends along the Y direction.

[0048] In this embodiment, the frame 2 is composed of a first frame 2a having an opening in the center serving as the light extraction portion 4, and a second frame 2b having no opening. The second frame 2b fits into the first frame 2a to form an internal space surrounded by the frame 2. Within this internal space, four lamp containers 3 and a pair of lamp electrodes (9a, 9b) for supplying power to the lamp containers 3 are arranged.

[0049] like Figure 2 As shown, a pair of lamp electrodes (9a, 9b) are fixed to the surface of the second frame 2b that contacts the internal space. Two connection terminals (8a, 8b) are provided on the surface of the second frame 2b that contacts the outside. The two connection terminals (8a, 8b) are electrically connected to the pair of lamp electrodes (9a, 9b) via the second frame 2b. Power supply lines (7a, 7b) supplied by an external power supply (not shown) are connected to the two connection terminals (8a, 8b). In addition, the pair of lamp electrodes (9a, 9b) are each made of a conductive material (e.g., aluminum, aluminum alloy, or stainless steel).

[0050] Figure 3 This is a perspective view showing four lamp containers (3a, 3b, 3c, 3d) separated in the Z direction, a pair of lamp electrodes (9a, 9b) separated in the Y direction, a starting electrode 5, and a starting discharge container 6 extracted from the ultraviolet irradiation device 10.

[0051] A pair of lamp electrodes (9a, 9b) is composed of a first electrode 9a and a second electrode 9b. The first electrode 9a and the second electrode 9b have the same shape. A plurality of recesses are formed on the +X side surfaces of the lamp electrodes (9a, 9b). The substantially V-shaped grooves of each recess extend in the Y direction. The lamp containers (3a, 3b, 3c, 3d) are arranged to be separated from each other in the Z direction so as to be sandwiched between the recesses of the pair of lamp electrodes (9a, 9b). The pair of lamp electrodes (9a, 9b) are in contact with the outer surfaces of the lamp containers (3a, 3b, 3c, 3d).

[0052] A discharge gas that generates excimer light is enclosed within the lamp vessel 3. A pair of lamp electrodes (9a, 9b) are located outside the lamp vessel 3, while the discharge gas is located within the lamp vessel 3. Therefore, the pair of lamp electrodes (9a, 9b) are not exposed to the discharge gas. When a high-frequency AC voltage, such as approximately 1 kHz to 5 MHz, is applied between the pair of lamp electrodes (9a, 9b), a dielectric barrier discharge is generated within the lamp vessel 3. Atoms constituting the gas species are excited or ionized, becoming excimers, and then emit excimer light as they transition to a ground state.

[0053] In this embodiment, the discharge gas is a mixed gas containing Kr and Cl2, and the excimer light emitted is ultraviolet light with a primary emission wavelength of approximately 222 nm. It is known that ultraviolet light in these wavelength bands minimizes the effects on the human body and exhibits high sterilization and virus inactivation properties. Therefore, the ultraviolet light irradiation device 10 is used in sterilization devices or virus inactivation devices, etc. However, the gas type of the discharge gas is not limited to the above. The gas type of the discharge gas can be one or more rare gases such as argon (Ar), krypton (Kr), and xenon (Xe), or a mixture of halogen gases such as fluorine (F), chlorine (Cl), iodine (I), and bromine (Br) with the aforementioned rare gases.

[0054] As another example of a combination of gas types, a mixed gas of krypton (Kr), chlorine (Cl), and argon (Ar) can be used as the discharge gas. In this case, krypton and chlorine function as the luminescent gases, while argon functions as the buffer gas. Alternatively, one or more rare gases selected from argon (Ar), neon (Ne), and helium (He) can be used as the buffer gas.

[0055] [Starting electrode]

[0056] like Figure 3 As shown in FIG, the ultraviolet irradiation device 10 includes a starting electrode 5. The starting electrode 5 assists in starting the lighting of the excimer lamp. Figure 4 The starting electrode 5 will be described in detail. Figure 4 This is an enlarged view of the vicinity of the starting electrode 5 in the UV irradiation device 10, viewed along the +X direction. The starting electrode 5 extends generally in the Y direction. The starting electrode 5 in this embodiment comprises a helical proximal portion 5a and a distal portion 5b, which has a smaller helix and is more rod-like than the proximal portion 5a. The helical proximal portion 5a exhibits elasticity in the Y direction. While the distal portion 5b is relatively straight compared to the proximal portion 5a, it exhibits a slight curve.

[0057] On the side surface 9as of the first electrode 9a (see Figure 4 ) has a recessed portion, within which the proximal portion 5a of the starting electrode 5 is disposed. The proximal portion 5a contacts the bottom of the recessed portion. This electrically connects the proximal portion 5a to the first electrode 9a. The distal portion 5b of the starting electrode 5 extends to the vicinity of the side surface 9bs of the second electrode 9b, which is opposite the side surface 9as of the first electrode 9a. Corona discharge is generated between the distal end 5c of the distal portion 5b and the second electrode 9b.

[0058] The shape of starting electrode 5 is not limited to that of this embodiment. The overall shape of starting electrode 5 may be a columnar shape, a rod shape, a thin plate shape, or the like. Furthermore, the shape of distal portion 5b of starting electrode 5 is not limited to a rod shape and may also be a thin plate shape, etc. However, it is preferred that distal portion 5b have a sharp tip 5c. This concentrates the electric field at tip 5c of starting electrode 5, facilitating discharge at tip 5c of starting electrode 5.

[0059] The starting electrode 5 is made of a conductive material. The starting electrode 5 can be a metal material with high corrosion resistance to oxidizing substances. For example, the starting electrode 5 can be made of titanium, aluminum, molybdenum, or stainless steel, and more preferably, gold, platinum, or tungsten.

[0060] [Starting discharge vessel]

[0061] like Figure 4 As shown, the starting discharge vessel 6 is arranged so as to surround the tip 5c of the starting electrode 5. The starting discharge vessel 6 has a bottomed cylindrical shape, comprising a cylindrical portion and a bottom portion that seals one end of the cylindrical portion. The tip 5c of the starting electrode 5 is pressed against the bottom portion of the starting discharge vessel 6 by the elastic force of the proximal portion 5a. The starting discharge vessel in this embodiment has a cylindrical portion, with the boundary between the cylindrical portion and the bottom portion connected with rounded corners. However, the starting discharge vessel is not limited to a cylindrical portion; it may also have a rectangular or other shape. Furthermore, the bottom portion is not limited to a flat surface; it may also have a hemispherical shape. The starting discharge vessel 6 is pressed against the second electrode 9b. The starting discharge vessel 6 functions as a dielectric between the tip 5c of the starting electrode and the second electrode 9b. Furthermore, the starting electrode 5 does not necessarily need to be in contact with the starting discharge vessel 6; it may be positioned at a distance sufficient to allow discharge.

[0062] The starting discharge vessel 6 can be made of a material that has high mechanical strength, insulating properties, and functions as a dielectric. For example, the starting discharge vessel 6 can be made of quartz glass, a ceramic material such as alumina, or a resin material such as PTFE. Furthermore, the starting discharge vessel 6 is preferably made of a material with high transmittance for ultraviolet light (the trigger light described below). For example, quartz glass is more preferably used for the starting discharge vessel 6.

[0063] Regarding the excimer emission generated within the lamp vessel 3, particularly when halogen gas is enclosed within the lamp vessel 3, the halogen gas, with its high electron affinity, gradually absorbs electrons. Therefore, if the lamp is temporarily extinguished for a prolonged period, current becomes difficult to flow to the discharge gas (electrons become difficult to transfer). This results in poor ignition startability. Therefore, a starting electrode 5 is used to generate trigger light L2, which is incident upon the lamp vessel 3. This light imparts optical energy to the discharge gas within the lamp vessel 3, inducing excitation of the excimer molecules within the lamp vessel 3 and generating excimer discharge.

[0064] Air (primarily containing nitrogen) exists around the tip 5c of the starting electrode 5. When the ultraviolet irradiation device 10 is operated, a voltage is applied not only to the pair of lamp electrodes (9a, 9b) but also between the starting electrode 5 and the second electrode 9b. Since the distance between the starting electrode 5 and the second electrode 9b is smaller than the distance between the pair of lamp electrodes (9a, 9b), dielectric breakdown occurs at a voltage lower than that within the lamp vessel 3, generating corona discharge in the atmosphere. This discharge generates trigger light L2.

[0065] Figure 5 This is the spectrum of the trigger light emitted by corona discharge in the atmosphere (hereinafter, "corona discharge in the atmosphere" may be referred to as "atmospheric discharge"). The trigger light is a continuous spectrum with multiple peak wavelengths, for example, with a peak wavelength between 226nm and 227nm. On the other hand, when the discharge gas enclosed in the lamp vessel 3 contains krypton (Kr) and chlorine (Cl2), the peak wavelength in the spectrum of the excimer light emitted from the lamp vessel 3 is 222nm. The peak wavelength of the trigger light exists near the peak wavelength of the excimer light. Therefore, the atmospheric discharge starting electrode 5 easily induces the excitation of the KrCl excimer light within the lamp vessel 3. When the trigger light generated by the starting electrode 5 enters the lamp vessel 3, the energy of this trigger light causes the excimer light emission within the lamp vessel 3 to begin within a short period of time (for example, within 2 seconds), igniting the excimer lamp (ultraviolet light irradiation device 10).

[0066] Furthermore, even after the excimer lamp is lit, a voltage is continuously applied to the tip 5c of the starting electrode 5, so trigger light may continue to be emitted from the tip 5c. Even in this case, because the power consumed at the tip 5c of the starting electrode 5 is extremely low, the illumination of the excimer lamp, which would normally be reduced due to power loss from the emission of the trigger light, does not typically occur. Furthermore, after the excimer lamp is lit, the discharge within the lamp vessel 3 becomes dominant, suppressing atmospheric discharge at the starting electrode 5. Therefore, the trigger light has a minimal impact on the excimer lamp.

[0067] exist Figure 5 While only the wavelength range of 200nm to 320nm of the spectrum generated by atmospheric discharge is shown, there are also emission bands in other ultraviolet wavelength regions, with multiple peaks. Therefore, the triggering light generated by atmospheric discharge is also useful for applications other than KrCl excimer lamps. For example, the peak wavelength of XeCl excimer lamps is 308nm, but this triggering light is also effective for XeCl excimer lamps.

[0068] The reason for using a starting discharge capacitor 6, which is arranged to surround the tip 5c of the starting electrode 5, as a dielectric will be explained. The atmospheric discharge generated near the tip 5c of the starting electrode 5 generates nitrogen oxides (hereinafter sometimes referred to as "NOx") such as nitric oxide and nitrogen dioxide from N2 and O2 in the atmosphere. Furthermore, the atmosphere contains water vapor (H2O), and NOx may react with H2O in the atmosphere to produce nitric acid gas (HNO3). Nitric acid gas is an oxidizing substance. NOx and oxidizing substances may adversely affect the ultraviolet irradiation device, surrounding equipment, people, and the environment.

[0069] [Starting the seal of the discharge vessel]

[0070] Figure 6 It is a further enlarged view of the periphery of the starting electrode 5 , showing a comparative embodiment in which the sealing portion of the starting discharge container 6 is not sealed. Figure 6 The comparison method is Figure 14 First, referring to this comparative embodiment, the problem of not sealing the starter discharge container 6 with the seal portion will be described, and then the reason why the problem can be solved by sealing the starter discharge container 6 with the seal portion will be described.

[0071] like Figure 6 As shown, the starting discharge container 6 is inserted into the recess provided in the first electrode 9a. There is a gap between the outer wall of the starting discharge container 6 and the inner wall of the recess. Through this gap, the recess of the first electrode 9a is connected to the inside of the starting discharge container 6. Therefore, the atmosphere existing outside the first electrode 9a penetrates into the inside of the starting discharge container 6 along the flow indicated by the arrow marked as F1. As mentioned above, since the atmosphere contains nitrogen and water vapor, nitric acid gas (HNO3) as an oxidizing substance is sometimes generated. Although the generation of nitric acid gas in a short period of time is trace, the influence of nitric acid gas generated continuously for a long time cannot be ignored as the life of the lamp is extended. The conductor connected to the starting electrode 5, that is, the connection portion 11 ( Figure 6 The oxidizing material 13 moves toward the connection portion 11, adheres to the connection portion 11, and corrodes the connection portion 11. It is understood that when the ultraviolet irradiation device is turned on for a long time, the progress of corrosion hinders electrical conduction to the starting electrode 5.

[0072] Corrosion will be described. When the oxidizing substance 13 is nitric acid gas and the corroded component is aluminum, the nitric acid gas comes into contact with the aluminum, causing a chemical reaction to produce nitrates (e.g., Al(NO3)3). The nitrates are in powder form and are emitted from the first electrode 9a. The first electrode 9a is reduced. As a result, the connection 11 between the first electrode 9a and the starting electrode 5 is reduced, resulting in poor conductivity. In addition, the connection 11 is also a part that is easily broken by the load associated with the pressure of the starting electrode 5. If the connection 11 breaks, the starting electrode 5 will no longer function and will not emit trigger light.

[0073] Therefore, a sealing portion is formed in the gap to airtightly seal the space including the starter discharge container 6. This prevents the moisture-containing atmosphere from entering the starter discharge container 6. This prevents the continuous generation of oxidizing substances in the starter discharge container 6.

[0074] exist Figure 4 In the embodiment, by attaching the sealing portion 7 to the open end of the starting discharge container 6, only the space of the starting discharge container 6 is hermetically sealed. The sealing portion 7 is penetrated by the starting electrode 5, and the interior of the starting discharge container 6 is hermetically sealed from the outside of the starting discharge container 6. Therefore, even if oxidizing substances are generated by the atmosphere inside the starting discharge container 6 during manufacturing, the oxidizing substances will not come into contact with the connecting portion 11, and corrosion at the connecting portion 11 can be suppressed. In other words, by Figure 4 The arrangement of the sealing portion 7 shown not only achieves the effect of suppressing the amount of oxidizing substances generated by blocking the atmosphere, but also achieves the effect of further suppressing corrosion by separating the space containing the portion susceptible to corrosion caused by the oxidizing substances from the space within the starting discharge vessel, where the oxidizing substances are generated. Furthermore, even if oxidizing substances are generated within the starting discharge vessel 6, they are prevented from leaking outside the starting discharge vessel 6. Furthermore, while oxidizing substances can adhere to the distal portion 5b of the starting electrode 5, corrosion at the distal portion 5b has minimal impact on conduction. If corrosion of the distal portion 5b is a concern, a highly corrosion-resistant material such as tungsten, gold, or platinum can be used for the distal portion 5b (starting electrode 5).

[0075] There are various methods for forming the sealing portion of the starting discharge container 6. When the starting discharge container 6 is made of a glass-like material, there is also a method of forming the sealing portion 7 by heat-forming a portion of the starting discharge container 6 to seal the starting discharge container 6. In this method, the sealing portion 7 is made of the same material as the starting discharge container 6. However, in this embodiment, the method of forming the sealing portion 7 by heat-forming a portion of the starting discharge container 6 to seal the starting discharge container 6 is not used.

[0076] When forming the seal portion 7 by heat-forming a portion of the starting discharge container 6 to seal the starting discharge container 6, the gas inside the starting discharge container 6 is exposed to high temperatures during the heat-forming process. The space inside the starting discharge container 6 after sealing becomes a reduced-pressure space with a pressure lower than atmospheric pressure. If the space inside the starting discharge container 6 is a reduced-pressure space, excessive discharge occurs in the starting electrode 5, which can easily wear the starting electrode 5. The space inside the starting discharge container 6 is preferably a space with a pressure around atmospheric pressure. Therefore, in this embodiment, a method of forming the seal portion 7 is employed without heat-forming a portion of the starting discharge container 6.

[0077] In this embodiment, a sealing portion 7 is used that is separate from the starting discharge container 6. In this embodiment, the sealing portion 7 is made of a different material than the starting discharge container 6. Since the properties required of the starting discharge container 6 differ from those required of the sealing portion 7, a material that better matches the properties required of the sealing portion 7 can be used for the sealing portion 7. Furthermore, a space with an atmospheric pressure around atmospheric pressure refers to a space within a range of ±30% of the pressure (unit: Pa) of the environment in which the ultraviolet irradiation device is located.

[0078] As the material of the sealing portion 7, it is considered to use ceramic materials such as quartz glass and alumina, resin materials such as silicone, epoxy, acrylic and polyurethane, or rubber materials. Since the starting electrode 5 passes through the sealing portion 7, a portion where the sealing portion 7 contacts the starting electrode 5 is inevitably generated. On the other hand, the thermal expansion coefficient of the sealing portion 7 is different from the thermal expansion coefficient of the starting electrode 5. Therefore, it is preferred to use a material with high elasticity for the sealing portion 7 so that the sealing portion 7 can easily adhere to the starting electrode 5 even if the temperature changes. As materials with high elasticity, for example, resin materials or rubber materials can be cited. In addition, near the front end 5c of the starting electrode 5, ozone (O3) is generated from oxygen molecules in the atmosphere by discharge, so it is preferred to use a material that is difficult to degrade by ozone, such as a resin material.

[0079] An adhesive may be used to seal the starting discharge container 6 and the sealing portion 7. Furthermore, since the opening diameter of the starting discharge container 6 is small, the sealing portion 7 itself may be formed of an adhesive. When the sealing portion 7 itself is formed of an adhesive, an epoxy or silicone adhesive is preferably used, as it bonds well to both the starting discharge container 6 and the starting electrode 5. In this embodiment, the use of an adhesive is optional and not essential. The sealing portion 7 may also be engaged with the starting discharge container 6. For example, a concave or convex portion may be formed on the outer wall of the starting discharge container 6 to prevent the sealing portion 7 from shifting.

[0080] If the sealing portion 7 is made of a hygroscopic material, this is preferred because it reduces the amount of water required to generate nitric acid from the starting discharge container 6. A hygroscopic material that cures through a condensation reaction (e.g., a moisture-curing resin) is particularly preferred. When an adhesive is used for the sealing portion 7, using a moisture-curing adhesive can achieve both the effects of curing the adhesive and removing moisture from the starting discharge container. Alternatively, a hygroscopic material may be disposed within the starting discharge container 6 separately from the sealing portion 7.

[0081] The sealing portion 7 can be made of a material with a thermosetting effect (typically a thermosetting adhesive). It is preferably a material that thermosets at 110°C or lower. If the temperature is 110°C or lower, the aforementioned disadvantage of the interior of the starting discharge container 6 becoming a decompressed space will not occur.

[0082] When sealing portion 7 is attached to starting discharge container 6, it may be attached with nitrogen gas sealed inside starting discharge container 6. By eliminating or reducing oxygen and water vapor inside starting discharge container 6, nitric acid gas can be prevented from being generated or its generation amount can be reduced.

[0083] [Deformation of the seal part]

[0084] Figure 7 The deformation mode of the sealing portion 7 is shown in FIG. Figure 7 In the embodiment shown, the sealing portion 7 is not attached to the open end of the starting discharge container 6, but is arranged so as to close the gap between the outer wall of the starting discharge container 6 and the inner wall of the recess of the first electrode 9a. The sealing portion 7 may also be an annular element surrounding the circumference of the starting discharge container 6. Figure 7 In the illustrated embodiment, the space including the starter discharge container 6 is also hermetically sealed, and the inflow of moisture-containing atmosphere from the outside can be prevented.

[0085] <Second embodiment>

[0086] Reference Figure 8 A second embodiment of the ultraviolet irradiation device will be described. Regarding the second embodiment, the contents other than those described below can be implemented in the same manner as the first embodiment and its modified forms. The same applies to the third embodiment and subsequent embodiments.

[0087] Figure 8This is an enlarged view of the periphery of the starting electrode 5 in the ultraviolet light irradiation device of the second embodiment. In this embodiment, there is a starting electrode 5 connected to the first electrode 9a and a starting electrode 15 connected to the second electrode 9b. The front end 5c of the starting electrode 5 and the front end 15c of the starting electrode 15 are arranged opposite each other. The starting electrodes (5, 15) are characterized by being arranged at the same potential as one of the pair of lamp electrodes and being arranged opposite a portion having the same potential as the other electrode, so as to discharge and generate trigger light L2.

[0088] The starting discharge container 6 is interposed between the front end 5c of the starting electrode 5 and the front end 15c of the starting electrode 15, surrounding both front ends (5c, 15c). The starting discharge container 6 is divided into a first space surrounding the front end 5c of the starting electrode 5 and a second space surrounding the front end 15c of the starting electrode 15. The sealing portion (7, 17) airtightly seals each space in the starting discharge container 6 while being penetrated by each of the starting electrodes (5, 15). The connection portion 11 between the starting electrode 5 and the first electrode 9a is located outside the starting discharge container 6.

[0089] <Third embodiment>

[0090] Reference Figure 9 A third embodiment of the ultraviolet light irradiation device will be described. Figure 9 This is an enlarged view of the area surrounding the starting electrode 5 in the ultraviolet light irradiation device of the third embodiment. In this embodiment, the starting electrode 5, connected to the first electrode 9a, is in the form of a coil wound with a thin, elongated conductive wire. The +Y-side ends of the multiple coils serve as the front ends 5c of the starting electrode 5, thereby achieving a wide discharge area. In this embodiment, the starting electrode 5, also in the form of a coil, is surrounded by the starting discharge container 6 and the sealing portion 7. The starting electrode 5 penetrates the sealing portion 7, and the connection 11 between the starting electrode 5 and the first electrode 9a is located outside the starting discharge container 6.

[0091] <Fourth embodiment>

[0092] Figure 10 This is a fourth embodiment of an ultraviolet irradiation device. The ultraviolet irradiation device 40 includes a lamp vessel 3 enclosing a discharge gas 3G. The lamp vessel 3 is elongated in the Y direction, and its cross-section along the XZ plane is a flat, generally rectangular shape. A first electrode 9a and a second electrode 9b are provided on a pair of flat outer surfaces of the lamp vessel 3 along the YZ plane. A high voltage is applied to the first and second electrodes 9a, 9b.

[0093] In this embodiment, the first electrode 9a is formed in a lattice shape, and the excimer light L1 can be taken out from the portion without the lattice. Figure 10The lattice pattern of the first electrode 9a cannot be visually confirmed in the figure, but the lattice pattern can be visually confirmed when observing the first electrode 9a in the -X direction. Furthermore, the shape of the first electrode 9a is not particularly limited as long as it can extract light. The second electrode 9b is an electrode that extends along the YZ plane. The second electrode 9b may also have a certain shape rather than extending along the plane. The first and second electrodes 9a, 9b are located on the outer surface of the lamp vessel 3, and therefore, neither the first electrode 9a nor the second electrode 9b is exposed to the discharge gas 3G.

[0094] The ultraviolet light irradiation device 10 includes a starting electrode 5 electrically connected to the second electrode 9b and at the same potential as the second electrode 9b, and a conductive member 12 electrically connected to the first electrode 9a and at the same potential as the first electrode 9a. The starting electrode 5 and the conductive member 12 are arranged opposite each other. The conductive member 12 has a flat portion at a position opposite the starting electrode 5. A starting discharge vessel 6 is interposed between the starting electrode 5 and the conductive member 12. The starting discharge vessel 6 surrounds the tip of the starting electrode 5. Atmospheric discharge generated at the tip of the starting electrode 5 emits triggering light L2. The triggering light L2 passes through the starting discharge vessel 6. The starting discharge vessel 6 is hermetically sealed by a sealing portion 7. The connection 11 between the starting electrode 5 and the lead wire connected to the starting electrode 5 is located outside the starting discharge vessel 6. The sealing portion 7 has a through-hole for the starting electrode 5 to pass through. The starting electrode 5 passes through this through-hole, but the sealing portion 7 and the starting electrode 5 are in close contact within the through-hole, maintaining an airtight state. This prevents atmospheric air outside the starting discharge vessel 6 from entering the starting discharge vessel 6. Furthermore, even if oxidizing substances are generated inside the starting discharge container 6 , they can be prevented from leaking out of the starting discharge container 6 .

[0095] In this embodiment, the starting electrode 5 is disposed outside the lamp vessel 3 in the Y direction of the lamp tube axis. However, the starting electrode 5 may not be located in this position. However, it is preferred that the tip 5 c of the starting electrode 5 be close to the lamp vessel 3. The distance between the tip 5 c of the starting electrode 5 and the lamp vessel 3 is preferably less than 30 mm, more preferably less than 20 mm, and even more preferably less than 15 mm.

[0096] <Fifth embodiment>

[0097] Figure 11 This is a fifth embodiment of an ultraviolet irradiation device. The ultraviolet irradiation device 50 includes a lamp vessel 3 enclosing a discharge gas 3G. The lamp vessel 3 in this embodiment has a double-tube structure that is elongated in the Y direction. The lamp vessel 3 includes an inner tube 3i and an outer tube 3o surrounding the inner tube 3i. The Y-direction ends of the inner tube 3i and outer tube 3o are sealed, forming a closed space between the inner tube 3i and outer tube 3o. The discharge gas 3G is enclosed in this closed space.

[0098] A first electrode 9a is provided on the outer circumferential wall of the outer tube 3o. The first electrode 9a is formed in a lattice pattern, allowing the excimer light L1 to be extracted from areas without lattice. A second electrode 9b is provided on the inner circumferential wall of the inner tube 3i. The second electrode 9b extends along the inner circumferential surface. High voltages are applied to the first and second electrodes 9a, 9b. Neither the first nor the second electrode 9a is exposed to the discharge gas 3G.

[0099] The ultraviolet light irradiation device 50 includes a starting electrode 5 electrically connected to the second electrode 9b and at the same potential as the second electrode 9b, and a conductive member 12 electrically connected to the first electrode 9a and at the same potential as the first electrode 9a. The starting electrode 5 and the conductive member 12 are arranged opposite each other. The starting discharge vessel 6 is hermetically sealed by a sealing portion 7. Locations susceptible to corrosion by oxidizing substances, including the connection 11 between the starting electrode 5 and the lead wire connected to the starting electrode 5, are located outside the starting discharge vessel 6. In this embodiment, the starting electrode 5 is located inside the inner tube 3i, but the starting electrode 5 may not be located in this location. However, as described above, it is preferred that the tip of the starting electrode 5 be close to the lamp vessel 3.

[0100] <Sixth embodiment>

[0101] Reference Figure 12 and Figure 13 A sixth embodiment of the ultraviolet light irradiation device will be described. Figure 12 This is an enlarged view showing the periphery of the starting electrode 5 in the ultraviolet light irradiation device 60 according to the sixth embodiment. Figure 13 The electrode pads (69a, 69b) are viewed in the -X direction. Figure 12 FIG. 6 is a diagram showing a UV irradiation device 60 with the lamp vessel 3 and the electrodes (9a, 9b) removed.

[0102] The ultraviolet irradiation device 60 includes a lamp vessel 3 in which a discharge gas 3G is sealed, and two electrodes (a first electrode 9 a and a second electrode 9 b ) arranged to be separated from each other in the −X direction on the outer surface of the lamp vessel 3 .

[0103] The first electrode 9a is electrically connected to the starting electrode 5 via the electrode pad 69a and the conductive path. The first electrode 9a and the starting electrode 5 have the same potential. The second electrode 9b is electrically connected to the conductive component 12 via the electrode pad 69b and the conductive path. The second electrode 9b and the conductive component 12 have the same potential. A pair of electrode pads (69a, 69b) are arranged on the substrate. The starting electrode 5 is exposed from the substrate 65. The conductive component 12 is embedded in the substrate 65. The substrate 65 is an insulator. It acts as a dielectric between the starting electrode 5 and the conductive component 12.

[0104] The starting electrode 5 of this embodiment is a creeping discharge type. Figure 12An extended discharge occurs in region a1, generating trigger light L2. The front end of the starting electrode 5 is surrounded by the starting discharge container 6, but the starting discharge container 6 is not located between the starting electrode 5 and the conductive member 12. The end of the starting discharge container 6 is airtightly fixed to the substrate 65 by a sealing portion 7, which is an adhesive. At this time, the adhesive is applied to cover the starting electrode 5, and the end of the starting discharge container 6 is bonded to the applied adhesive. Thus, the sealing portion 7, which is an adhesive, can airtightly seal the starting discharge container 6. Areas susceptible to corrosion by oxidizing substances, such as the starting electrode 5 and the electrode pads (69a, 69b) connected via a wire connected to the starting electrode 5, are located outside the starting discharge container 6.

[0105] While various embodiments and variations of the present invention have been described above based on the accompanying drawings, the specific configuration is not limited to these embodiments and variations. The scope of the present invention is indicated not only by the description of the embodiments and variations described above, but also by the claims, and includes all modifications within the meaning and scope equivalent to the claims.

[0106] The structures adopted in the above-mentioned embodiments and modifications can be applied to any other embodiments and modifications. The specific configuration of each part is not limited to the above-mentioned embodiments and modifications, and various modifications can be made without departing from the scope of the present invention.

[0107] [Example]

[0108] An experiment was conducted to investigate the life-extending effect of providing a seal 7, which hermetically seals the starting discharge vessel 6, in a UV irradiation device. The starting electrode 5, starting discharge vessel 6, and seal 7 of the UV irradiation device described in the first embodiment were used. The experiment involved preparing samples with and without seals, and measuring the starting time after a predetermined lighting period. During the starting time measurement, all samples were left in darkness for 50 hours to prevent the starting performance from being affected by ambient light from the UV irradiation device. The experimental conditions are shown below.

[0109] [Light container]

[0110] Material = Quartz glass, Outer diameter = 6mm, Total length = 60mm

[0111] [Discharge gas]

[0112] Gas pressure: 19kPa, Gas type: Cl2, Kr mixed gas

[0113] [First Electrode and Second Electrode]

[0114] Material = Aluminum, Length = 60mm, Distance between electrodes = 6mm

[0115] [External power supply]

[0116] Voltage: 5kV, Frequency: 100kHz

[0117] [Starting electrode]

[0118] Material = Tungsten, Shape = Figure 4 The shape described in the figure, electrode diameter = 0.25 mm

[0119] Length = 17mm

[0120] [Starting discharge vessel]

[0121] Outer diameter = 4mm, inner diameter = 2.4mm, length = 13mm

[0122] [Seal part]

[0123] Material = Silicone adhesive

[0124] The experimental results are shown in Table 1.

[0125] [Table 1]

[0126]

[0127] Until the cumulative lighting time reached 5,000 hours, there was no difference in startup time between the sample with and without a seal. After 6,000 hours, the sample without a seal began to experience a delay in startup. At 8,000 hours, the excimer lamp in the sample without a seal did not ignite even after 60 seconds. In contrast, the sample with a seal showed no delay in startup, even after 8,000 hours.

[0128] Disassembly of a sample without a seal, which had been lit for a cumulative period of 8,000 hours, revealed that powdered nitrate adhered to the connection between starting electrode 5 and first electrode 9a connected to starting electrode 5, causing poor conduction. Disassembly of a sample with a seal, which had been lit for a cumulative period of 8,000 hours, revealed no dust at the connection between starting electrode 5 and first electrode 9a connected to starting electrode 5.

[0129] Description of Reference Numerals

[0130] 2: Frame

[0131] 2a: The first frame (composing the frame)

[0132] 2b: The second frame (forming the frame body)

[0133] 3: Light container

[0134] 3G: Discharge gas

[0135] 3i: Inner tube

[0136] 3o: outer tube

[0137] 4: Light extraction unit

[0138] 5, 15: Start electrode

[0139] 5a: Proximal part (of the starting electrode)

[0140] 5b: Distal part (of the starting electrode)

[0141] 5c, 15c: Front end (of the starting electrode)

[0142] 6: Start the discharge container

[0143] 7: Sealing part

[0144] 9a: First electrode (constituting a pair of lamp electrodes)

[0145] 9b: Second electrode (constituting a pair of lamp electrodes)

[0146] 10, 40, 50, 60: UV irradiation device

[0147] 11: Connection

[0148] 12: Conductive parts

[0149] 13: Oxidizing substances

[0150] 65: Substrate

[0151] 69a, 69b: Electrode pads

[0152] L1: Excimer light

[0153] L2: Trigger light

Claims

1. A UV irradiation device, characterized in that: have: A lamp container encloses a discharge gas for generating excimer light; a pair of lamp electrodes arranged so as not to be exposed to the discharge gas and for applying a voltage to the lamp container; a starting electrode having the same potential as one of the pair of lamp electrodes and being arranged opposite to a portion having the same potential as the other electrode, thereby discharging to generate trigger light; a starting discharge container, surrounding the front end of the starting electrode and allowing the trigger light to pass through; as well as a sealing portion for hermetically sealing at least the space within the starting discharge container; The sealing portion is made of a material different from that of the starting discharge container.

2. The ultraviolet irradiation device according to claim 1, characterized in that The sealing portion hermetically seals only the space within the starting discharge container.

3. The ultraviolet irradiation device according to claim 1, characterized in that A portion of the starting discharge vessel is located between the starting electrode and a portion at the same potential as the other electrode.

4. The ultraviolet irradiation device according to claim 1, characterized in that The sealing portion is made of a material having a hygroscopic effect.

5. The ultraviolet irradiation device according to claim 1, characterized in that: The sealing portion is formed of an epoxy-based or silicone-based adhesive.

6. The ultraviolet irradiation device according to claim 1, characterized in that Atmospheric components are present inside the starting discharge vessel.

7. The ultraviolet irradiation device according to any one of claims 1 to 5, characterized in that: The discharge gas includes Kr and Cl 2 .

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