Ultraviolet irradiation device

Abstract

In an ultraviolet irradiation device, the maintainability of the barrier discharge lamp is improved, and the generation of nitrogen oxides in the gap between the external electrode and the discharge tube is suppressed. [Solution] The ultraviolet irradiation device comprises: a discharge tube; a conductive cooling section having a recess in which the discharge tube is provided; first and second holders having conductivity and provided at the end of the recess of the cooling section where it opens; and a cover provided on the side of the cooling section where it opens. The inner wall of the recess of the cooling section, the end of the first holder on the discharge tube side, and the end of the second holder on the discharge tube side have a concave curved surface shape that follows the outer wall of the discharge tube. An AC voltage is applied to the cooling section, the first holder, the second holder, and the internal electrodes. An inert gas is supplied to the space enclosed by the recess of the cooling section, the first holder, the second holder, and the cover.

Description

Technical Field

[0001] Embodiments of the present invention relate to an ultraviolet irradiation device.

Background Art

[0002] There is an ultraviolet irradiation device including a barrier discharge lamp that irradiates ultraviolet rays. The ultraviolet irradiation device including the barrier discharge lamp is used, for example, for surface treatment such as removal of organic substances (photo cleaning treatment) adhering to the surface of an object to be irradiated with ultraviolet rays, surface modification, and formation of an oxide film. The barrier discharge lamp has, for example, an internal electrode provided inside a light emitting tube and an external electrode provided outside the light emitting tube. When an alternating voltage is applied to the internal electrode and the external electrode, dielectric barrier discharge occurs, and ultraviolet rays having a specific wavelength are irradiated according to the type of gas enclosed inside the light emitting tube.

[0003] Here, as described above, the external electrode of the barrier discharge lamp is provided outside the light emitting tube. In this case, when the area where the external electrode and the internal electrode provided inside the light emitting tube face each other is increased, dielectric barrier discharge between the external electrode and the internal electrode is likely to occur. However, when the area where the external electrode and the internal electrode provided inside the light emitting tube face each other is increased, the central angle of the external electrode may exceed 180° when viewed from the direction in which the light emitting tube extends. When the central angle of the external electrode exceeds 180°, it becomes difficult to attach the light emitting tube to the external electrode and to remove the light emitting tube from the external electrode in the direction intersecting the direction in which the light emitting tube extends. Therefore, the maintainability of the barrier discharge lamp is significantly reduced.

[0004] Furthermore, increasing the surface area where the external electrode and the internal electrode located inside the discharge tube face each other makes it easier for a gap to form between the external electrode and the discharge tube. If there is a gap between the external electrode and the discharge tube, an air discharge may occur in the gap, and nitrogen oxides may be generated from the air (a mixture of nitrogen and oxygen) in the gap. When nitrogen oxides are generated, there is a risk that they will react with moisture in the atmosphere to produce nitrates. When nitrates are generated, they may adhere to the surface of the object or accumulate in the gap, potentially damaging the discharge tube.

[0005] Therefore, a technique has been proposed in which the barrier discharge lamp is housed inside a container and the inside of the container is filled with an inert gas such as nitrogen gas. In this way, the gap between the external electrode and the discharge tube is filled with inert gas, which can suppress the generation of the aforementioned nitrogen oxides.

[0006] However, housing the barrier discharge lamp inside the container presents new challenges, such as increasing the size of the ultraviolet irradiation device, increasing the consumption of inert gas, and lengthening the time required to replace the air inside the container with inert gas.

[0007] Therefore, there was a need to develop an ultraviolet irradiation device that could improve the maintainability of a barrier discharge lamp, even when the area between the external electrode and the internal electrode located inside the discharge tube is increased, and that could suppress the generation of nitrogen oxides in the gap between the external electrode and the discharge tube. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2009-72645 [Overview of the project] [Problems that the invention aims to solve]

[0009] The problem that the present invention aims to solve is to provide an ultraviolet irradiation device that can improve the maintainability of a barrier discharge lamp even when the area in which the external electrode and the internal electrode provided inside the discharge tube face each other is increased, and that can suppress the generation of nitrogen oxides in the gap between the external electrode and the discharge tube. [Means for solving the problem]

[0010] The ultraviolet irradiation device according to the embodiment comprises: a barrier discharge lamp having a discharge tube extending in one direction and having a substantially cylindrical shape, and an internal electrode extending inside the discharge tube; a conductive cooling section having a recess in which the discharge tube is provided; a conductive first holder and a second holder provided at the end of the cooling section where the recess opens, and facing each other on either side of the discharge tube; and a cover provided on the side of the cooling section where the recess opens. The inner wall of the recess of the cooling section, the end of the first holder on the discharge tube side, and the end of the second holder on the discharge tube side have a concave curved surface shape that follows the outer wall of the discharge tube. An AC voltage is applied to the cooling section, the first holder, the second holder, and the internal electrode. An inert gas is supplied to the space demarcated by the recess of the cooling section, the first holder, the second holder, and the cover. [Effects of the Invention]

[0011] According to embodiments of the present invention, even when the area in which the external electrode and the internal electrode provided inside the discharge tube face each other is increased, it is possible to provide an ultraviolet irradiation device that can improve the maintainability of the barrier discharge lamp and suppress the generation of nitrogen oxides in the gap between the external electrode and the discharge tube. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic exploded view illustrating the ultraviolet irradiation device according to this embodiment. [Figure 2]This is a schematic cross-sectional view of an ultraviolet irradiation device in the direction of the AA line. [Figure 3] This is a schematic diagram illustrating a barrier discharge lamp. [Modes for carrying out the invention]

[0013] The embodiments will be illustrated below with reference to the drawings. In each drawing, similar components are denoted by the same reference numerals, and detailed descriptions will be omitted as appropriate.

[0014] Figure 1 is a schematic exploded view illustrating the ultraviolet irradiation device 100 according to this embodiment. Figure 2 is a schematic cross-sectional view of the ultraviolet irradiation device 100 in the direction of the AA line. As shown in Figures 1 and 2, the ultraviolet irradiation device 100 includes, for example, a barrier discharge lamp 1, a cooling unit 2, a clamp 3, a holder 4 (corresponding to an example of a first holder and a second holder), and a cover 5.

[0015] Figure 3 is a schematic diagram illustrating barrier discharge lamp 1. As shown in Figure 3, the barrier discharge lamp 1 includes, for example, a discharge tube 11, an internal electrode 12, a reflective film 13, a base 14, and lead wires 15. In the ultraviolet irradiation device 100 according to this embodiment, the cooling unit 2 on which the barrier discharge lamp 1 is provided and the holder 4 provided on the cooling unit 2 function as external electrodes.

[0016] The discharge tube 11 has a substantially cylindrical shape, with a total length (length in the central axis direction) that is longer than the diameter of the tube. The discharge tube 11 extends in one direction. The discharge tube 11 is, for example, a substantially cylindrical tube. A sealing portion 11a is provided at each of the ends on both sides in the direction in which the discharge tube 11 extends. By providing the sealing portion 11a, the internal space of the discharge tube 11 is hermetically sealed. The sealing portion 11a is formed, for example, using a pinch seal method or a shrink seal method.

[0017] In addition, a conductive portion 11b and an outer lead 11c can be provided inside the sealing portion 11a. For example, one conductive portion 11b can be provided for one sealing portion 11a. The planar shape of the conductive portion 11b is, for example, a quadrilateral. The conductive portion 11b has a thin film shape and is formed from, for example, molybdenum foil.

[0018] The outer lead 11c has a linear shape and can be provided in the sealing portion 11a on at least the side where the lead wire 15 is provided. One end portion of the outer lead 11c is electrically connected to the conductive portion 11b. The other end portion of the outer lead 11c is exposed from the sealing portion 11a. The outer lead 11c is, for example, a linear body containing molybdenum or the like.

[0019] A gas is enclosed in the internal space of the arc tube 11. In the barrier discharge lamp 1, barrier discharge is performed between the internal electrode 12 and the cooling portion 2 and the holder 4 which also function as external electrodes, to give high-energy electrons to the enclosed gas to generate excimer-excited molecules. When the excimer-excited molecules return to their original state, ultraviolet rays having a specific main wavelength are generated according to the type of the gas. For example, when xenon gas is enclosed in the internal space of the arc tube 11, ultraviolet rays having a main wavelength of 172 nm are generated.

[0020] Therefore, the gas enclosed in the internal space of the arc tube 11 can be appropriately changed according to the use of the ultraviolet irradiation device 100. The gas enclosed in the internal space of the arc tube 11 can be, for example, a noble gas such as krypton, xenon, argon, neon, or a mixed gas in which a plurality of types of noble gases are mixed. The gas can further contain a halogen gas or the like as necessary.

[0021] The pressure of the gas (enclosure pressure) at 25°C in the internal space of the light-emitting tube 11 can be, for example, about 80 kPa to 200 kPa. The pressure of the gas (enclosure pressure) at 25°C in the internal space of the light-emitting tube 11 can be determined by the standard state of the gas (SATP (Standard Ambient Temperature and Pressure): temperature 25°C, 1 bar).

[0022] The light-emitting tube 11 is formed from a material with a high ultraviolet transmittance. For example, the light-emitting tube 11 can be formed from synthetic quartz glass.

[0023] The internal electrode 12 is provided inside the light-emitting tube 11 and extends inside the light-emitting tube 11. The internal electrode 12 has, for example, a coil 12a and legs 12b. The coil 12a and the legs 12b can be integrally formed. The coil 12a and the legs 12b are formed from a wire material containing, for example, tungsten or doped tungsten. The wire diameter (diameter) of the wire material is, for example, about 0.2 mm to 1.0 mm.

[0024] The coil 12a has a spiral shape and is provided in the internal space of the light-emitting tube 11. The coil 12a extends along the central axis 11e of the internal space of the light-emitting tube 11 in the central region of the internal space of the light-emitting tube 11.

[0025] The legs 12b are provided at each of the both ends on both sides of the coil 12a. The legs 12b have a linear shape and extend along the central axis 11e of the light-emitting tube 11 from the ends of the coil 12a. The ends of the legs 12b are electrically connected to the conductive part 11b inside the sealing part 11a.

[0026] The reflective film 13 can be provided between the cooling part 2 and the holder 4 that also function as external electrodes and the internal electrode 12 (coil 12a). For example, the reflective film 13 has a film shape and is provided on the inner wall of the light-emitting tube 11. The reflective film 13 reflects the ultraviolet rays that are generated in the internal space of the light-emitting tube 11 and do not face the irradiation direction toward the irradiation direction.

[0027] Furthermore, as shown in Figure 2, when viewed from the direction in which the discharge tube 11 extends, the reflective film 13 has an aperture 13c that faces the cooling section 2 on either side of the central axis 11e of the discharge tube 11. Ultraviolet light generated in the internal space of the discharge tube 11 is emitted to the outside through the aperture 13c. When viewed from the direction in which the discharge tube 11 extends, the aperture angle θ between the line segment 13a (corresponding to an example of a first line segment) connecting the central axis 11e of the discharge tube 11 and one end of the aperture 13c, and the line segment 13b (corresponding to an example of a second line segment) connecting the central axis 11e of the discharge tube 11 and the other end of the aperture 13c, can be, for example, about 120°.

[0028] The thickness of the reflective film 13 is, for example, about 100 μm to 300 μm. The reflective film 13 contains, for example, SiO2. The reflective film 13 may also contain particles that scatter ultraviolet light. The particles that scatter ultraviolet light include, for example, aluminum oxide.

[0029] The base 14 is provided at each end of the discharge tube 11 in the direction in which it extends. The base 14 covers the ends of the discharge tube 11. The base 14 is formed from an insulating material such as steatite or aluminum oxide.

[0030] The lead wire 15 is electrically connected to the end of the outer lead 11c that is exposed from the sealing portion 11a. The lead wire 15 is electrically connected to the internal electrode 12 via the outer lead 11c and the conductive portion 11b. The lead wire 15 is electrically connected, for example, to a lighting circuit provided outside the ultraviolet irradiation device 100. Note that the lead wire 15 can be provided on only one end of the discharge tube 11, as shown in Figure 3, or on both ends of the discharge tube 11.

[0031] The lighting circuit includes, for example, an inverter that converts power from an AC power source into high-voltage, high-frequency power (for example, a sine wave with a frequency of 37 kHz). For example, the lighting circuit lights up the barrier discharge lamp 1 with a lamp power of approximately 2.4 kW.

[0032] As shown in Figures 1 and 2, the cooling section 2 faces the discharge tube 11. The cooling section 2 extends in the direction in which the discharge tube 11 extends. A recess 2a opens at one end 2c of the cooling section 2 in a direction intersecting the direction in which the discharge tube 11 extends. The recess 2a extends in the direction in which the discharge tube 11 extends. A barrier discharge lamp 1 (discharge tube 11) can be installed inside the recess 2a. The inner wall of the recess 2a faces the discharge tube 11. The inner wall of the recess 2a has a concave curved surface shape that follows the outer wall of the discharge tube 11.

[0033] In this case, as shown in Figure 2, a gap can be provided between the inner wall of the recess 2a and the discharge tube 11. If a gap is provided between the inner wall of the recess 2a and the discharge tube 11, manufacturing errors in the outer diameter of the discharge tube 11 can be absorbed. In addition, contact between the discharge tube 11 and the cooling unit 2 due to thermal expansion when the barrier discharge lamp 1 is lit can be suppressed. Therefore, damage to the discharge tube 11 when the barrier discharge lamp 1 is lit can be suppressed.

[0034] The center of the circle of curvature of the inner wall of the recess 2a can, for example, coincide with the central axis 11e of the discharge tube 11. When viewed from the direction in which the discharge tube 11 extends, the central angle of the recess 2a with respect to the central axis 11e can be 180° or less. In this way, the barrier discharge lamp 1 (discharge tube 11) can be easily installed and removed through the opening of the recess 2a in a direction intersecting the direction in which the discharge tube 11 extends. Therefore, the maintainability of the barrier discharge lamp 1 can be improved.

[0035] As shown in Figure 1, the cooling unit 2 can be provided, for example, in the housing 200 in which the ultraviolet irradiation device 100 is installed. The cooling unit 2 dissipates the heat generated when the barrier discharge lamp 1 is lit and also functions as an external electrode for the barrier discharge lamp 1. Therefore, the cooling unit 2 is made of a material with high thermal conductivity and conductivity. The cooling unit 2 can be made of a metal such as aluminum or stainless steel.

[0036] As shown in Figure 2, a flow path 2b can be provided inside the cooling unit 2. The flow path 2b extends in the direction in which the discharge tube 11 extends. A refrigerant such as water is supplied to one end of the flow path 2b via a pipe fitting or the like. The refrigerant that has flowed inside the flow path 2b is discharged to the outside of the cooling unit 2 from the other end of the flow path 2b via a pipe fitting or the like.

[0037] Furthermore, an AC voltage is applied from a lighting circuit located outside the ultraviolet irradiation device 100 to the cooling unit 2 and holder 4, which function as external electrodes of the barrier discharge lamp 1, and to the internal electrode 12.

[0038] As shown in Figure 1, the clamp 3 can be provided on each of the ends of the barrier discharge lamp 1. The clamp 3 detachably holds the ends of the barrier discharge lamp 1. The clamp 3 has, for example, a base 3a and a fixing part 3b. The base 3a can be provided, for example, on a housing 200 on which an ultraviolet irradiation device 100 is installed. The fixing part 3b is detachably provided, for example, on the end of the base 3a opposite to the housing 200 side using fastening members such as screws. A recess is provided on the end of the base 3a opposite to the housing 200 side. A recess is provided on the end of the fixing part 3b on the base 3a side. When the fixing part 3b is attached to the base 3a, the base 14 of the barrier discharge lamp 1 is held by the recess of the base 3a and the recess of the fixing part 3b.

[0039] Furthermore, the clamp 3 can be equipped with a packing that seals the space defined by the cooling unit 2, the holder 4, and the cover 5 in an airtight manner.

[0040] The material of clamp 3 is not particularly limited, as long as it has a certain degree of rigidity, heat resistance, and resistance to ultraviolet rays. Clamp 3 can be made from a metal such as aluminum or stainless steel.

[0041] As shown in Figures 1 and 2, the pair of holders 4 are provided at the end 2c of the cooling section 2 where the recess 2a opens, and face each other with the light-emitting tube 11 in between. The pair of holders 4 are detachably attached to the end 2c of the cooling section 2 where the recess 2a opens using fastening members such as screws.

[0042] As mentioned above, the reflective film 13 is provided with an aperture 13c for emitting ultraviolet light. Therefore, as can be seen from Figure 2, if the ultraviolet light emitted from the aperture 13c is blocked by the pair of holders 4 or the packing 5a described later, the intensity of ultraviolet light on the surface of the object being irradiated may decrease.

[0043] Therefore, it is preferable that one holder 4 and packing 5a be placed in the region between the line segment 13a and the end portion 2c of the cooling section 2. It is preferable that the other holder 4 and packing 5a be placed in the region between the line segment 13b and the end portion 2c of the cooling section 2. In this way, it is possible to suppress the blocking of ultraviolet rays emitted from the aperture 13c by the pair of holders 4 and packing 5a.

[0044] The holder 4 is plate-shaped and extends in the direction in which the discharge tube 11 extends. The end 4a of the holder 4 on the discharge tube 11 side has a concave curved surface shape that follows the outer wall of the discharge tube 11. The center of the circle of curvature of the end 4a of the holder 4 can be aligned with, for example, the central axis 11e of the discharge tube 11. The shape of the end 4a on the discharge tube 11 side can be, for example, the same as the shape of the inner wall of the recess 2a of the cooling section 2.

[0045] In this case, as shown in Figure 2, a gap can be provided between the end 4a of the holder 4 and the discharge tube 11. If a gap is provided between the end 4a of the holder 4 and the discharge tube 11, manufacturing errors in the outer diameter of the discharge tube 11 can be absorbed. In addition, contact between the discharge tube 11 and the holder 4 due to thermal expansion when the barrier discharge lamp 1 is lit can be suppressed. Therefore, damage to the discharge tube 11 when the barrier discharge lamp 1 is lit can be suppressed.

[0046] When the pair of holders 4 are attached to the end 2c of the cooling unit 2, the pair of holders 4 and the inner wall of the recess 2a of the cooling unit 2 cooperate to prevent the barrier discharge lamp 1 from shifting position. When the pair of holders 4 are removed from the end 2c of the cooling unit 2, the barrier discharge lamp 1 can be removed from the recess 2a of the cooling unit 2 in a direction intersecting the direction in which the discharge tube 11 extends. In other words, the barrier discharge lamp 1 can be prevented from shifting position without compromising the maintainability of the barrier discharge lamp 1 as described above.

[0047] Furthermore, the pair of holders 4 are conductive and can be electrically connected to the cooling unit 2. As mentioned above, the cooling unit 2 also functions as an external electrode of the barrier discharge lamp 1. Therefore, if the conductive pair of holders 4 are electrically connected to the cooling unit 2, the cooling unit 2 and the pair of holders 4 can function as external electrodes of the barrier discharge lamp 1.

[0048] The pair of holders 4 can be made from a metal such as aluminum or stainless steel. In this case, the material of the pair of holders 4 may be the same as or different from the material of the cooling unit 2.

[0049] As can be seen in Figure 2, by using the pair of holders 4 as the external electrodes of the barrier discharge lamp 1, the area in which the external electrodes and the internal electrodes 12 face each other can be increased by the area of ​​the ends 4a of the pair of holders 4. As a result, dielectric barrier discharge between the external electrodes and the internal electrodes 12 becomes easier to occur, which in turn allows for a reduction in the power supply voltage of the lighting circuit, for example.

[0050] Furthermore, since the pair of holders 4 are detachably provided, even if the area where the external electrode and the internal electrode 12 face each other is increased by providing the pair of holders 4, the maintainability of the barrier discharge lamp 1 described above is not impaired.

[0051] As mentioned above, gaps are provided between the inner wall of the recess 2a of the cooling unit 2 and the discharge tube 11, and between the end 4a of the holder 4 and the discharge tube 11. As mentioned above, such gaps can absorb manufacturing errors in the outer diameter of the discharge tube 11 and suppress contact between the discharge tube 11 and the cooling unit 2 and holder 4 due to thermal expansion.

[0052] However, if there is a gap between the cooling unit 2 and holder 4, which function as external electrodes, and the discharge tube 11, which has an internal electrode 12 inside, an air discharge may occur in the gap. In this case, if there is air (a mixture of nitrogen and oxygen) in the atmosphere where the ultraviolet irradiation device 100 is installed in the gap, nitrogen oxides may be generated when an air discharge occurs. When nitrogen oxides are generated, they may react with moisture in the atmosphere to produce nitrates. When nitrates are generated, they may adhere to the surface of the object being irradiated with ultraviolet light, or accumulate in the gap, potentially damaging the discharge tube 11.

[0053] Therefore, the ultraviolet irradiation device 100 according to this embodiment is provided with a cover 5. As shown in Figure 2, the cover 5 is provided on the side of the cooling section 2 where the recess 2a opens. The cover 5 extends in the direction in which the discharge tube 11 extends. In a direction intersecting the direction in which the discharge tube 11 extends, the cover 5 faces the barrier discharge lamp 1. When viewed from the direction in which the discharge tube 11 extends, the surface of the cover 5 facing the discharge tube 11 is a curved surface that protrudes away from the discharge tube 11. The center of the circle of curvature of the surface of the cover 5 facing the discharge tube 11 can coincide with, for example, the central axis 11e of the discharge tube 11. For example, the cover 5 can be part of a cylinder. In this case, the central axis of the cylinder can coincide with, for example, the central axis 11e of the discharge tube 11.

[0054] In this way, the gap between the cover 5 and the discharge tube 11 can be made approximately uniform in the direction intersecting the direction in which the discharge tube 11 extends. As a result, the inert gas, which will be described later, can flow smoothly through the gap between the cover 5 and the discharge tube 11, thereby suppressing stagnation and preventing the time required to replace air with the inert gas from being prolonged. In addition, since the volume of the space to which the inert gas is supplied can be reduced, the ultraviolet irradiation device 100 can be made more compact.

[0055] In other words, the ultraviolet irradiation device 1 according to this embodiment allows for miniaturization and optimization of purging with inert gas.

[0056] Ultraviolet light emitted from the barrier discharge lamp 1 enters the object being irradiated with ultraviolet light through the cover 5. Therefore, the cover 5 is made of a material that has high transmittance of ultraviolet light with a dominant wavelength of 200 nm or less. For example, the cover 5 can be made of synthetic quartz glass.

[0057] Each of the pair of holders 4 is provided with a packing 5a. The packing 5a extends in the direction in which the light-emitting tube 11 extends. The end of the packing 5a on the holder 4 side is joined to the holder 4. A recess is provided at the end of the packing 5a opposite to the holder 4 side. The end of the cover 5, in a direction intersecting the direction in which the light-emitting tube 11 extends, is detachably fitted into the recess of the packing 5a.

[0058] In the direction in which the discharge tube 11 extends, each end of the cover 5 is detachably attached to the clamp 3 via a packing. Also, in the direction in which the discharge tube 11 extends, each end of the cooling section 2 and the holder 4 is detachably attached to the clamp 3 via a packing.

[0059] Therefore, the gap between the cover 5 and the discharge tube 11, the gap between the inner wall of the recess 2a of the cooling section 2 and the discharge tube 11, and the gap between the end 4a of the holder 4 and the discharge tube 11 are sealed to be airtight. Furthermore, these gaps are in communication with each other.

[0060] Furthermore, if the cover 5 is provided to be removable via a packing 5a, it becomes easier to remove and attach the cover 5 when performing maintenance on the barrier discharge lamp 1. This improves the maintainability of the barrier discharge lamp 1.

[0061] Furthermore, an inert gas is supplied to the space defined by the recess 2a of the cooling unit 2, the pair of holders 4, and the cover 5. For example, as shown in Figure 2, the cooling section 2 can be provided with a plurality of holes 2f that communicate with the gap between the inner wall of the recess 2a of the cooling section 2 and the light-emitting tube 11. In the direction in which the light-emitting tube 11 extends, the holes 2f can be provided on one end side of the cooling section 2 and on the other end side of the cooling section 2.

[0062] An inert gas is supplied to a hole 2f provided on one end of the cooling unit 2. The supplied inert gas flows into the gap between the cover 5 and the discharge tube 11 through the gap between the inner wall of the recess 2a of the cooling unit 2 and the discharge tube 11, and the gap between the end 4a of the holder 4 and the discharge tube 11. The inert gas that has flowed into the gap between the cover 5 and the discharge tube 11 flows through the gap between the cover 5 and the discharge tube 11 and is discharged to the outside of the cooling unit 2 through the gap between the end 4a of the holder 4 and the discharge tube 11, and the gap between the inner wall of the recess 2a of the cooling unit 2 and the discharge tube 11, through a hole 2f provided on the other end of the cooling unit 2.

[0063] In this case, the supply of inert gas may be continuous or intermittent. Furthermore, the inert gas may be supplied as needed. However, a continuous supply of inert gas can improve the reliability of the ultraviolet irradiation device 100 and extend the maintenance cycle.

[0064] An inert gas can be any gas that does not contain oxygen. For example, inert gases include nitrogen gas and noble gases.

[0065] As described above, with the ultraviolet irradiation device according to this embodiment, even when the area where the external electrodes (cooling unit 2 and holder 4) and the internal electrodes 12 provided inside the discharge tube 11 face each other is increased, the maintainability of the barrier discharge lamp 1 can be improved, and the generation of nitrogen oxides in the gap between the external electrodes (cooling unit 2 and holder 4) and the discharge tube 11 can be suppressed.

[0066] Although several embodiments of the present invention have been illustrated above, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. Furthermore, the embodiments described above can be implemented in combination with each other.

[0067] The following are additional notes regarding the embodiments described above.

[0068] (Note 1) A barrier discharge lamp having a light-emitting tube extending in one direction and having a substantially cylindrical shape, and an internal electrode extending inside the light-emitting tube; A cooling section having conductivity and a recess in which the light-emitting tube is provided; Having conductivity, provided at the end where the recess of the cooling section opens, and comprising a first holder and a second holder facing each other with the light-emitting tube in between; The cooling section has a cover provided on the side where the recess opens; It is equipped with, The inner wall of the recess in the cooling section, the end of the first holder on the discharge tube side, and the end of the second holder on the discharge tube side have a concave curved surface shape that conforms to the outer wall of the discharge tube. An AC voltage is applied to the cooling unit, the first holder, the second holder, and the internal electrodes. An ultraviolet irradiation device in which an inert gas is supplied to the space demarcated by the recess of the cooling section, the first holder, the second holder, and the cover.

[0069] (Note 2) When viewed from the direction in which the discharge tube extends, the central angle of the recess in the cooling section, with respect to the central axis of the discharge tube, is 180° or less. The ultraviolet irradiation device according to Appendix 1, wherein the first holder and the second holder are detachably provided at the end of the cooling section where the recess opens.

[0070] (Note 3) It has a film-like appearance and further comprises a reflective film provided on the inner wall of the light-emitting tube, When viewed from the direction in which the discharge tube extends, The reflective film has an aperture that faces the cooling section across the central axis of the discharge tube, The first holder is provided in the region between the first line segment connecting the central axis of the discharge tube and one end of the aperture, and the end of the cooling section where the recess opens. The ultraviolet irradiation device according to Appendix 1 or 2, wherein the second holder is provided in the region between a second line segment connecting the central axis of the discharge tube and the other end of the aperture, and the end of the cooling section where the recess opens.

[0071] (Note 4) The ultraviolet irradiation device according to any one of the appendices 1 to 3, wherein, when viewed from the direction in which the discharge tube extends, the surface of the cover facing the discharge tube is a curved surface that protrudes away from the discharge tube, and the center of the circle of curvature of the surface of the cover coincides with the central axis of the discharge tube. [Explanation of Symbols]

[0072] 1 Barrier discharge lamp, 2 Cooling section, 2a Recess, 4 Holder, 4a End, 5 Cover, 11 Discharge tube, 11e Central axis, 12 Internal electrode, 13 Reflective film, 13a Line segment, 13b Line segment, 13c Aperture, 100 Ultraviolet irradiation device, θ Aperture angle

Claims

1. A barrier discharge lamp having a light-emitting tube extending in one direction and having a substantially cylindrical shape, and an internal electrode extending inside the light-emitting tube; A cooling section having conductivity and a recess in which the light-emitting tube is provided; A first holder and a second holder that are conductive, provided at the end where the recess of the cooling section opens, and facing each other with the light-emitting tube in between; The cooling section has a cover provided on the side where the recess opens; It is equipped with, The inner wall of the recess in the cooling section, the end of the first holder on the discharge tube side, and the end of the second holder on the discharge tube side have a concave curved surface shape that conforms to the outer wall of the discharge tube. An AC voltage is applied to the cooling unit, the first holder, the second holder, and the internal electrodes. An ultraviolet irradiation device in which an inert gas is supplied to the space demarcated by the recess of the cooling section, the first holder, the second holder, and the cover.

2. When viewed from the direction in which the discharge tube extends, the central angle of the recess in the cooling section, with respect to the central axis of the discharge tube, is 180° or less. The ultraviolet irradiation device according to claim 1, wherein the first holder and the second holder are detachably provided at the end of the cooling section where the recess opens.

3. It has a film-like appearance and further comprises a reflective film provided on the inner wall of the light-emitting tube, When viewed from the direction in which the discharge tube extends, The reflective film has an aperture that faces the cooling section across the central axis of the discharge tube, The first holder is provided in the region between the first line segment connecting the central axis of the discharge tube and one end of the aperture, and the end of the cooling section where the recess opens. The ultraviolet irradiation device according to claim 1 or 2, wherein the second holder is provided in the region between the second line segment connecting the central axis of the discharge tube and the other end of the aperture and the end of the cooling section where the recess opens.

4. The ultraviolet irradiation device according to claim 1 or 2, wherein, when viewed from the direction in which the light-emitting tube extends, the surface of the cover facing the light-emitting tube is a curved surface that protrudes away from the light-emitting tube, and the center of the circle of curvature of the surface of the cover coincides with the central axis of the light-emitting tube.

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