JP7464907B2 - Ultraviolet irradiation equipment - Google Patents

Description

An embodiment of the present invention relates to an ultraviolet irradiation device.

There are barrier discharge lamps that emit ultraviolet rays with a peak wavelength of 200 nm or less. Barrier discharge lamps are used for surface treatments such as removing organic matter attached to the surface of an object (photocleaning treatment), surface modification, and formation of oxide films. Barrier discharge lamps have, for example, an arc tube made of a dielectric, an internal electrode provided inside the arc tube, and an external electrode provided outside the arc tube. When an AC voltage is applied between the internal electrode and the external electrode, a dielectric barrier discharge occurs, and ultraviolet rays having a specific wavelength are emitted according to the type of gas sealed in the internal space of the arc tube.

Here, if the arc tube is cylindrical, repeated expansion and contraction during blinking, etc. may cause the arc tube to rotate little by little in the radial direction, which may cause the position of the barrier discharge lamp to shift around the tube axis. If the position of the barrier discharge lamp shifts around the tube axis, the irradiation position of the ultraviolet light may shift or the illuminance may change.
Therefore, there has been a demand for the development of an ultraviolet irradiation device that can prevent the position of the barrier discharge lamp from shifting around the tube axis.

JP 2013-211164 A

The problem that this invention aims to solve is to provide an ultraviolet irradiation device that can prevent the position of a barrier discharge lamp from shifting around the tube axis.

The ultraviolet irradiation device according to the embodiment includes a cylindrical arc tube with a rare gas sealed in the internal space; an internal electrode having a coil disposed in the internal space; an external electrode disposed on the outside of the arc tube; a cooling section disposed on the outside of the external electrode via a gap; a terminal cover disposed on the end of the arc tube and having a first flat surface on the side; and a positioning section having a hole in which the terminal cover is disposed. A second flat surface that can come into contact with the first flat surface of the terminal cover is provided on the inner wall surface of the hole.

According to an embodiment of the present invention, it is possible to provide an ultraviolet irradiation device that can prevent the position of a barrier discharge lamp from shifting around the tube axis.

1 is a schematic side view illustrating an ultraviolet irradiation device according to an embodiment of the present invention; 2 is a schematic side view of the ultraviolet irradiation device in FIG. 1 taken along line AA. 1 is a schematic diagram illustrating a barrier discharge lamp. 11 is a schematic side view illustrating a positioning portion. FIG. 4 is a schematic cross-sectional view illustrating a cooling unit. FIG. 13A and 13B are schematic perspective views illustrating a pair of holding portions. 13 is a schematic side view illustrating an ultraviolet irradiation device according to another embodiment. FIG. 13 is a schematic side view illustrating an ultraviolet irradiation device according to another embodiment. FIG. 13 is a schematic side view illustrating an ultraviolet irradiation device according to another embodiment. FIG.

Hereinafter, an embodiment will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and detailed description thereof will be omitted as appropriate.
FIG. 1 is a schematic side view illustrating an ultraviolet irradiation device 1 according to the present embodiment.
FIG. 2 is a schematic side view of the ultraviolet irradiation device 1 in FIG. 1 taken along line AA.

As shown in Figures 1 and 2, the ultraviolet irradiation device 1 can be provided with a barrier discharge lamp 2, a positioning unit 3, a positioning unit 4, a frame 5, a lighting circuit 6, a gas supply unit 7, a controller 8, a cooling unit 9, and a support unit 12.
Although the example has been described in which three barrier discharge lamps 2 are provided, the number of barrier discharge lamps 2 can be changed as appropriate depending on the size and number of objects to be irradiated with ultraviolet light. In other words, it is sufficient that at least one barrier discharge lamp 2 is provided.

FIG. 3 is a schematic diagram illustrating the barrier discharge lamp 2 .
As shown in FIG. 3, the barrier discharge lamp 2 can be provided with an arc tube 21, an internal electrode 22, a reflective film 23, a terminal cover 24, lead wires 25, and an external electrode .

The arc tube 21 is cylindrical and has a long overall length (length along the tube axis 21d) compared to the tube diameter. The arc tube 21 can be, for example, a cylindrical tube. A sealing portion 21a is provided at each of the two ends of the arc tube 21 in the direction along the tube axis 21d. By providing the sealing portion 21a, the internal space of the arc tube 21 can be airtightly sealed. The sealing portion 21a can be formed, for example, using a pinch seal method or a shrink seal method.

In addition, for example, a conductive part 21b and an outer lead 21c can be provided inside each sealing part 21a. For example, one conductive part 21b can be provided for each sealing part 21a. The planar shape of the conductive part 21b can be a rectangle. For example, the conductive part 21b has a thin film shape. For example, the conductive part 21b can be formed from molybdenum foil.

The outer lead 21c is linear and can be provided inside the sealing portion 21a on at least the side where the lead wire 25 is provided. One end of the outer lead 21c is electrically connected to the conductive portion 21b. The vicinity of the end of the outer lead 21c can be laser welded or resistance welded to the conductive portion 21b, for example. The other end of the outer lead 21c can be exposed from the sealing portion 21a. The outer lead 21c can include, for example, molybdenum.

A rare gas is sealed in the internal space of the arc tube 21. In the barrier discharge lamp 2, a barrier discharge is performed between the internal electrode 22 and the external electrode 26, and high energy electrons are given to the sealed rare gas to generate excimer excited molecules. When the excimer excited molecules return to their original state, light having a specific peak wavelength is generated according to the type of rare gas. Therefore, the rare gas sealed in the internal space of the arc tube 21 can be changed appropriately according to the application of the barrier discharge lamp 2. The rare gas sealed in the internal space of the arc tube 21 can be, for example, krypton, xenon, argon, neon, etc. Alternatively, a mixed gas of multiple types of rare gases can be sealed in the internal space of the arc tube 21. Furthermore, halogen gas or the like can be further sealed as necessary.

The pressure (filled pressure) of the rare gas in the internal space of the arc tube 21 at 25°C can be, for example, about 80 kPa to 200 kPa. The pressure (filled pressure) of the rare gas in the internal space of the arc tube 21 at 25°C can be determined from the standard ambient temperature and pressure (SATP: temperature 25°C, 1 bar).

For example, when optically cleaning the surface of a glass plate for a flat panel display, it is preferable to fill the gas with xenon. The pressure at which xenon is filled can be, for example, about 93 kPa. If the rare gas filled with xenon is xenon, ultraviolet light with a peak wavelength of 172 nm can be generated, thereby improving the cleaning effect.

Here, when a barrier discharge is generated (when the barrier discharge lamp 2 is turned on), ultraviolet rays are generated in the internal space of the arc tube 21. The generated ultraviolet rays are irradiated to the outside through the arc tube 21. For this reason, the arc tube 21 is formed, for example, from a material that has a high transmittance of ultraviolet rays with a peak wavelength of 200 nm or less. The arc tube 21 can be formed, for example, from a material containing _SiO2 . The arc tube 21 can be formed, for example, from synthetic quartz glass.

The internal electrode 22 can have a coil 22a and a leg 22b. The coil 22a and the leg 22b can be formed integrally. The coil 22a and the leg 22b can be formed by plastic processing a wire. The wire diameter (diameter) of the wire can be, for example, about 0.2 mm to 1.0 mm.

The coil 22a and the leg 22b may contain, for example, tungsten as a main component. The tungsten content may be, for example, 50 wt% or more. In this case, the dimensional stability of the coil 22a can be improved by using doped tungsten, which is tungsten with potassium or the like added.

The coil 22a is helical and is provided in the internal space of the light-emitting tube 21. The coil 22a extends along the tube axis 21d of the light-emitting tube 21 through the central region of the internal space of the light-emitting tube 21. The pitch dimension P1 of the coil 22a can be, for example, about 10 mm to 120 mm.

A gap can be provided between the coil 22a and the inner wall of the arc tube 21. The gap can be, for example, 10 mm or less. Note that no gap may be provided and the coil 22a and the reflective film 23 may be in contact with each other. If the reflective film 23 is not provided, the coil 22a and the inner wall of the arc tube 21 may be in contact with each other. If the gap is equal to or less than a predetermined dimension, a stable barrier discharge can be generated at a low voltage. Therefore, for example, the outer diameter of the coil 22a can be set so that a predetermined gap is provided according to the inner diameter of the arc tube 21.

The legs 22b are provided at both ends of the coil 22a. The legs 22b are linear and extend from the ends of the coil 22a along the tube axis 21d of the light-emitting tube 21.

The end of leg 22b is electrically connected to conductive portion 21b inside sealing portion 21a. The vicinity of the end of leg 22b can be laser welded or resistance welded to conductive portion 21b, for example.

The reflective film 23 is in the form of a film and can be provided on the inner wall of the light emitting tube 21. The reflective film 23 can be provided between the external electrode 26 and the internal electrode 22 (coil 22a). The reflective film 23 reflects ultraviolet light that is generated in the internal space of the light emitting tube 21 and does not travel in the direction of irradiation, toward the direction of irradiation. If the reflective film 23 is provided, the efficiency of extracting ultraviolet light can be improved. Furthermore, if the reflective film 23 is provided, the area of the light emitting tube 21 onto which ultraviolet light directly enters can be reduced, thereby suppressing chemical structural changes in the light emitting tube 21 caused by ultraviolet light.

The thickness of the reflective film 23 can be, for example, about 100 μm to 300 μm, which makes it easy to maintain a good reflectance for ultraviolet light.
The reflective film 23 may contain, for example, SiO ₂ (silicon dioxide), and may also contain particles that scatter ultraviolet light (for example, aluminum oxide particles).

The reflective film 23 is not necessarily required and can be omitted. However, as mentioned above, if the reflective film 23 is provided, the efficiency of extracting ultraviolet light can be improved and chemical structural changes to the light-emitting tube 21 can be suppressed.

The terminal cover 24 is provided on each of the two end portions of the light emitting tube 21 in the direction along the tube axis 21d. The terminal cover 24 covers, for example, the sealing portion 21a. The terminal cover 24 can be formed from an insulating material such as resin or ceramics. The terminal cover 24 can be formed from, for example, steatite, aluminum oxide, or the like. The terminal cover 24 may be in contact with the external electrode 26 or may be spaced apart from the external electrode 26.

The lead wire 25 can be electrically connected to the end of the outer lead 21c exposed from the sealing portion 21a. The lead wire 25 is electrically connected to the internal electrode 22 via the outer lead 21c and the conductive portion 21b. As shown in FIG. 2, the lead wire 25 can be electrically connected to the lighting circuit 6. Note that the lead wire 25 can be provided only on one end side of the light-emitting tube 21 as shown in FIG. 3, or can be provided on both ends of the light-emitting tube 21.

The external electrode 26 can be provided on the outside of the light emitting tube 21. The external electrode 26 extends along the tube axis 21d of the light emitting tube 21. If a reflective film 23 is provided, the external electrode 26 can be provided in a position facing the reflective film 23.

In addition, when the length of the arc tube 21 in the direction along the tube axis 21d is long, as shown in FIG. 2, multiple external electrodes 26 can be provided for one arc tube 21. When a barrier discharge is generated, heat is generated along with ultraviolet rays. When the temperature of the arc tube 21 increases due to the generated heat, the arc tube 21 may be deformed. In this case, the longer the length of the arc tube 21 in the direction along the tube axis 21d, the more likely it is that deformation will occur, and the greater the amount of deformation. If multiple external electrodes 26 are provided for one arc tube 21, each of the multiple external electrodes 26 can individually follow the deformation state of the arc tube 21. Therefore, it is possible to suppress changes in the positional relationship between the arc tube 21 and the external electrode 26, and further, the positional relationship between the coil 22a of the internal electrode 22 and the external electrode 26. As a result, it is possible to stabilize the barrier discharge, thereby improving the uniformity of the illuminance.

At least a portion of the surface of the external electrode 26 facing the arc tube 21 can be in contact with the outer surface of the arc tube 21. The external electrode 26 can be, for example, a thin metal plate that has been plastically processed to fit the outer shape of the arc tube 21. The external electrode 26 can be made of a conductive material such as a metal. The external electrode 26 can be made of, for example, stainless steel, aluminum, or the like. When a barrier discharge is generated, heat is generated along with ultraviolet light. Therefore, if the external electrode 26 is made of a material with high thermal conductivity such as a metal, the external electrode 26 can be used as a heat dissipation member.

When viewed from the direction along the tube axis 21d of the light-emitting tube 21, if the central angle of the external electrode 26 is smaller than 180°, the area where the external electrode 26 and the internal electrode 22 face each other becomes too small, and there is a risk that the amount of ultraviolet light generated will be reduced. On the other hand, if the central angle is larger than 300°, the ultraviolet light generated in the internal space of the light-emitting tube 21 will be easily absorbed by the external electrode 26, and there is a risk that the efficiency of extracting the ultraviolet light will decrease. For this reason, it is preferable that the central angle of the external electrode 26 is 180° or more and 300° or less. In this way, it is possible to ensure the necessary amount of ultraviolet light generated and to prevent a decrease in the efficiency of extracting the ultraviolet light.

Here, the arc tube 21, the internal electrode 22, the reflective film 23, etc. are more likely to wear out than the external electrode 26. Therefore, if the external electrode 26 can be removed from the arc tube 21, it is possible to improve maintenance and reduce running costs. For example, the external electrode 26 can have at least one mounting portion 26a that protrudes outward. The external electrode 26 illustrated in FIG. 2 has four mounting portions 26a. The mounting portion 26a can be provided with a hole into which a fastening member such as a screw is inserted. The external electrode 26 (mounting portion 26a) can be attached to the end surface of the cooling portion 9 opposite the frame 5 side together with the holding portion 9d using a fastening member such as a screw (see FIG. 5).

FIG. 4 is a schematic side view illustrating the positioning portion 3 and the positioning portion 4. As shown in FIG.
FIG. 4 is a schematic side view of the ultraviolet irradiation device 1 in FIG. 2 taken along line BB.
In order to avoid complication, the support portion 12 is omitted in FIG.
The positioning portion 3 prevents the barrier discharge lamp 2 from being displaced around the tube axis 21d.
2 and 4, at least one positioning portion 3 can be provided for one barrier discharge lamp 2. However, if one positioning portion 3 is provided for one terminal cover 24, rotation of the barrier discharge lamp 2 can be more effectively suppressed. The positioning portion 3 can be attached to the frame 5 using a fastening member such as a screw. The positioning portion 4 can also be formed integrally with the frame 5.

The positioning part 3 is plate-shaped and has a hole 3a in which the terminal cover 24 is provided. The hole 3a penetrates the positioning part 3 in the thickness direction and opens on the end face of the positioning part 3 opposite the frame 5 side.

The inner wall surface of the hole 3a is provided with a pair of flat surfaces 3a1 (corresponding to an example of a second flat surface) that are parallel to each other. The flat surface 3a1 can be, for example, a surface that is approximately perpendicular to the surface 5a of the frame 5 to which the positioning portion 3 is attached. In addition, a pair of flat surfaces 24a (corresponding to an example of a first flat surface) that are parallel to each other is provided on the side surface of the terminal cover 24. The distance between the flat surfaces 3a1 and 3a1 can be the same as or slightly larger than the distance between the flat surfaces 24a and 24a. In other words, at least one of the pair of flat surfaces 3a1 is in contact with the flat surface 24a. In this way, it is possible to prevent the position of the barrier discharge lamp 2 from shifting around the tube axis 21d.

Although the flat surface 3a1 that is approximately perpendicular to the surface 5a of the frame 5 has been exemplified, it may be a flat surface that is inclined with respect to the surface 5a of the frame 5, or a flat surface that is parallel to the surface 5a of the frame 5. In this case, a flat surface may be provided on the side of the terminal cover 24 to match the flat surface of the positioning portion 3. However, if the flat surface 3a1 is approximately perpendicular to the surface 5a of the frame 5, it becomes easy to attach and detach the barrier discharge lamp 2 to and from the positioning portion 3 even if the distance between the barrier discharge lamps 2 is small.

If the positioning portion 3 is provided, the position of the barrier discharge lamp 2 around the tube axis 21d can be determined simply by inserting the terminal cover 24 of the barrier discharge lamp 2 into the hole 3a of the positioning portion 3. In addition, it is possible to prevent the position of the barrier discharge lamp 2 around the tube axis 21d from shifting.
That is, the barrier discharge lamp 2 can be easily attached and detached, and the position of the barrier discharge lamp 2 around the tube axis 21d can be prevented from shifting.

The positioning portion 4 prevents the barrier discharge lamp 2 from moving in the direction along the tube axis 21d. As shown in Figs. 2 and 4, a pair of positioning portions 4 can be provided for one barrier discharge lamp 2 or for multiple barrier discharge lamps 2 arranged side by side. The barrier discharge lamp 2 can be provided in the space between the positioning portions 4. The shortest distance between the positioning portions 4 can be the same as or slightly larger than the distance between the end face of the terminal cover 24 and the end face of the terminal cover 24 (the length of the barrier discharge lamp 2). In other words, at least one of the pair of positioning portions 4 is in contact with the end face of the terminal cover 24. In this way, the barrier discharge lamp 2 can be prevented from moving in the direction along the tube axis 21d.

The shape of the positioning portion 4 may be columnar. The shape of the positioning portion 4 may be, for example, cylindrical or prismatic. The shape of the positioning portion 4 may also be a tapered shape such as a cone, a truncated cone, a pyramid, or a truncated pyramid, or a shape with an inclined side on the terminal cover 24 side. If the shape of the positioning portion 4 is a tapered shape or a shape with an inclined side, it becomes easy to attach the barrier discharge lamp 2 between the positioning portions 4.

The positioning part 4 can be attached to the surface 5a of the frame 5 to which the positioning part 3 is attached, for example, using a fastening member such as a screw. The positioning part 4 can also be formed integrally with the frame 5.

If the positioning parts 4 are provided, the position of the barrier discharge lamp 2 in the direction along the tube axis 21d can be determined simply by mounting the barrier discharge lamp 2 between the positioning parts 4. Also, deviation of the position of the barrier discharge lamp 2 in the direction along the tube axis 21d can be prevented.
That is, the barrier discharge lamp 2 can be easily attached and detached, and the position of the barrier discharge lamp 2 in the direction along the tube axis 21d can be prevented from shifting.

The material of the positioning portion 3 and the positioning portion 4 is not particularly limited as long as it has a certain degree of rigidity, heat resistance, and resistance to ultraviolet rays. However, it is preferable to use a material that can prevent the terminal cover 24 from being scratched when the positioning portion 3 and the positioning portion 4 come into contact with the terminal cover 24. It is preferable to use a resin such as a fluororesin as the material of the positioning portion 3 and the positioning portion 4.

The frame 5 can be provided so as to face the object to be irradiated with ultraviolet light. The frame 5 can also be provided in a position facing the object when irradiating the object with ultraviolet light, and moved from the position facing the object during maintenance or the like. For example, the frame 5 can be provided inside an opening and closing cover provided above the object.

There are no particular limitations on the structure of the frame 5, and it can be a framework structure as illustrated in Figure 2, or it can be a plate-like body, etc.

2, the lighting circuit 6 can be electrically connected to the internal electrode 22 via the wiring 6b, the terminal 6a, and the lead wire 25. The lighting circuit 6 can also be electrically connected to the external electrode 26 via the wiring 6c. As shown in FIG. 5, which will be described later, the attachment portion 26a of the external electrode 26 is provided on the cooling portion 9. The cooling portion 9 is made of a metal such as aluminum or stainless steel. Therefore, the lighting circuit 6 can also be electrically connected to the external electrode 26 via the wiring 6c and the cooling portion 9. During maintenance, the barrier discharge lamp 2 (external electrode 26) may be removed, but the cooling portion 9 is rarely removed. Therefore, if the wiring 6c is connected to the cooling portion 9 instead of the external electrode 26, the removal and attachment of the wiring 6c can be omitted during maintenance. Note that, although one lighting circuit 6 is configured to light three barrier discharge lamps in FIG. 1, it is also possible to provide separate lighting circuits for multiple lamps.

The terminal 6a may have an insulating portion 6a1 and a conductive portion 6a2. The insulating portion 6a1 may be formed of an insulating material such as fluororesin or ceramics. The insulating portion 6a1 may be attached to the frame 5 using a fastening member such as a screw. The conductive portion 6a2 may be formed of a conductive material such as stainless steel or nickel. One end of the conductive portion 6a2 is exposed from one end of the insulating portion 6a1 and is electrically connected to the lead wire 25. The other end of the conductive portion 6a2 is exposed from the other end of the insulating portion 6a1 and is electrically connected to the wiring 6b. In addition, when the lead wire 25 is connected to the lighting circuit 6, the terminal 6a and the wiring 6b may be omitted. However, if the terminal 6a and the wiring 6b are provided, it is possible to prevent ultraviolet rays and ozone from entering the inside of the frame 5. In addition, since the length of the lead wire 25 can be shortened, it is possible to improve the workability when attaching and detaching the barrier discharge lamp 2. Furthermore, the length of the lead wire 25 can be made constant, improving the versatility of the barrier discharge lamp 2.

The lighting circuit 6 can have an inverter that converts the power from the AC power source into high-voltage, high-frequency power (e.g., a sine wave with a frequency of 37 kHz). For example, the lighting circuit 6 can light the barrier discharge lamp 2 with a lamp power of about 2.4 kW.

The gas supply unit 7 supplies gas to a hole 9c provided in the cooling unit 9. The gas supply unit 7 can be provided with a gas supply source 71 and a gas control unit 72. The gas supply source 71 and the gas control unit 72 can be connected by a pipe 73. The gas control unit 72 and the cooling unit 9 can be connected by a pipe 74.

The gas supply source 71 may be, for example, a cylinder containing high-pressure gas or factory piping for supplying high-pressure gas. The gas may be, for example, dry air, nitrogen gas, or a rare gas (e.g., argon, neon, helium, etc.). In this case, when a barrier discharge is performed, an air discharge may occur in the gap 9a between the cooling unit 9 and the external electrode 26. If the gas in the gap 9a contains oxygen and nitrogen, the oxygen may be ionized by the air discharge, and the ionized oxygen may react with the nitrogen to produce nitrogen oxides (NOx).

Furthermore, when the barrier discharge lamp is turned on and ultraviolet light of 172 nm is irradiated, ozone is generated by reaction with oxygen in the atmosphere. When ozone and nitrogen oxides are generated, they may react to generate dinitrogen pentoxide (N ₂ O ₅ ). In this case, if the gas in the gap 9 a contains moisture such as water vapor, the moisture may react with dinitrogen pentoxide to generate nitric acid (HNO ₃ ). If the generated nitric acid adheres to the outer surface of the arc tube 21, the optical properties of the arc tube 21 may deteriorate, and the transmission of ultraviolet light may be suppressed.

If this chemical reaction occurs repeatedly each time the barrier discharge lamp 2 is turned on, the efficiency of extracting ultraviolet light may decrease over time. In addition, if nitric acid drips and adheres to an object, it may cause damage to the object.

Therefore, it is desirable that the gap 9a between the cooling section 9 and the external electrode 26 is sufficiently large so that aerial discharge does not occur. If the gap 9a is narrow and aerial discharge occurs, it is preferable to reduce the oxygen concentration in the gap 9a, for example, by using a gas that does not contain oxygen or a gas with a lower oxygen concentration than air as the cooling supply gas. For example, it is preferable that the gas be nitrogen gas or a rare gas. In this case, using nitrogen gas can reduce running costs.

The gas control unit 72 can, for example, control the flow rate of the gas supplied to the cooling unit 9. The gas control unit 72 can indirectly control the flow rate of the gas by controlling the pressure of the gas supplied to the cooling unit 9. That is, the gas control unit 72 can control at least one of the gas flow rate and the gas pressure. The gas control unit 72 can also have a function of switching between starting and stopping the gas supply.

The controller 8 can have a calculation element such as a CPU (Central Processing Unit) and a storage element such as a semiconductor memory. The controller 8 can be, for example, a computer. The storage element can store a control program that controls the lighting circuit 6 and the gas supply unit 7. Based on the control program stored in the storage element, the calculation element can control switching between applying and stopping the application of power to the barrier discharge lamp 2, switching between supplying and stopping the supply of gas to the cooling unit 9, and the flow rate of the gas supplied. The controller 8 can also be provided with an input unit through which an operator inputs data, a monitor that displays the operating status and abnormality display of the ultraviolet irradiation device 1, a power switch, etc.

As shown in FIG. 2, the cooling unit 9 can be attached to the surface 5a of the frame 5 using a fastening member such as a screw. The cooling unit 9 can be provided between the positioning units 3.

FIG. 5 is a schematic cross-sectional view illustrating the cooling unit 9.
FIG. 5 is a schematic cross-sectional view of the cooling unit 9 taken along line CC in FIG.
As shown in FIG. 5, a gap 9a can be provided between the surface 9b of the cooling part 9 on the external electrode 26 side and the outer surface of the external electrode 26. That is, the cooling part 9 is provided outside the external electrode 26 via the gap 9a. The cooling part 9 can be opposed to the external electrode 26 via the gap 9a. If the dimension S of the gap 9a in the direction perpendicular to the tube axis 21d of the arc tube 21 is made too small, as described above, aerial discharge occurs between the cooling part 9 and the external electrode 26, and when the arc tube 21 is deformed by heat generated by the barrier discharge, a part of the arc tube 21 may come into contact with the cooling part 9. If a part of the arc tube 21 comes into contact with the cooling part 9, the flow of the gas supplied to the gap 9a is hindered, and the cooling of the arc tube 21 may be suppressed. On the other hand, if the dimension S of the gap 9a is made too large, the flow rate of the gas supplied to the gap 9a is slowed down, and the heat dissipation from the arc tube 21 may be suppressed or regions of different temperatures may be generated in the arc tube 21. According to the findings of the present inventors, it is preferable that the dimension S of the gap 9a is 0.5 mm or more and 8 mm or less. If the dimension S of the gap 9a is within this range, it is possible to effectively cool the arc tube 21. In this case, the distance L between the surface 9b of the cooling part 9 on the external electrode 26 side and the outer surface of the arc tube 21 can be set to 1 mm or more, for example, when the thickness of the external electrode 26 is 0.5 mm.

The surface 9b of the cooling section 9 facing the external electrode 26 can be curved. For example, the surface 9b can be part of the side of a cylinder centered on the tube axis 21d of the light-emitting tube 21. In this way, it is easy to make the dimension S of the gap 9a approximately constant. Therefore, the light-emitting tube 21 can be cooled effectively.

The cooling section 9 is block-shaped and extends in a direction along the tube axis 21d of the light-emitting tube 21. The cooling section 9 is preferably made of a material with high thermal conductivity. The cooling section 9 can be made of metal such as aluminum or stainless steel. Inside the cooling section 9, holes 9c for flowing gas can be provided. The holes 9c extend along the tube axis 21d of the light-emitting tube 21. As shown in FIG. 2, both ends of the holes 9c are blocked by plugs 9c1. There is no particular limit to the number or cross-sectional shape of the holes 9c, but if multiple holes 9c are provided, the light-emitting tube 21 can be effectively cooled and the occurrence of temperature distribution in the light-emitting tube 21 can be suppressed.

As shown in FIG. 2, the hole 9c can be provided with a supply hole 9c2. One end of the supply hole 9c2 opens into the hole 9c, and the other end opens, for example, to the surface of the cooling part 9 opposite the external electrode 26 side. The supply hole 9c2 can be connected to a pipe 74 via a pipe joint. There is no limit to the number of supply holes 9c2, but it is preferable to provide multiple supply holes 9c2. For example, a supply hole 9c2 can be provided near each of the ends on both sides of the hole 9c. In this way, gas can be supplied from both ends of the hole 9c, so that the flow rate of the gas supplied to the surface of the light-emitting tube 21 can be prevented from varying.

As shown in FIG. 2, the hole 9c can be provided with a plurality of exhaust holes 9c3. The plurality of exhaust holes 9c3 can be arranged in a line in a direction along the tube axis 21d of the light-emitting tube 21. One end of the exhaust hole 9c3 opens into the hole 9c, and the other end opens into the gap 9a. The opening dimensions of the plurality of exhaust holes 9c3 may be the same or different. For example, the central region of the light-emitting tube 21 is likely to be hotter than the vicinity of the end of the light-emitting tube 21. Therefore, the opening dimension of the exhaust hole 9c3 facing the central region of the light-emitting tube 21 can be made larger than the opening dimension of the exhaust hole 9c3 facing the vicinity of the end of the light-emitting tube 21. In this way, the flow rate of the gas supplied to the central region of the light-emitting tube 21, which is likely to be hotter, can be increased. Therefore, the light-emitting tube 21 can be effectively cooled, and the occurrence of temperature distribution in the light-emitting tube 21 can be suppressed.

The pitch dimension P2 of the multiple exhaust holes 9c3 can be, for example, equal to or smaller than the pitch dimension P1 of the coil 22a. The pitch dimension P2 can be, for example, 10 mm or more and 30 mm or less. The intervals between the multiple exhaust holes 9c3 may be approximately constant or may be different. As described above, the temperature of the central region of the arc tube 21 is likely to be higher than that of the vicinity of the end of the arc tube 21. Therefore, the pitch dimension of the exhaust holes 9c3 facing the central region of the arc tube 21 can be made smaller than the pitch dimension of the exhaust holes 9c3 facing the vicinity of the end of the arc tube 21. In this way, the flow rate of gas supplied to the central region of the arc tube 21, which is likely to be heated, can be increased. Therefore, the arc tube 21 can be effectively cooled and the occurrence of temperature distribution in the arc tube 21 can be suppressed.

5, the exhaust hole 9c3 may have a shape extending toward the tube axis 21d of the light emitting tube 21. In this way, the gas can be sprayed onto the surface of the light emitting tube 21, and it becomes easy to cause the gas to flow approximately evenly over the surface of the light emitting tube 21.
Furthermore, the exhaust hole 9c3 may be a slit or the like extending in a direction along the tube axis 21d of the light emitting tube 21. If the exhaust hole 9c3 is a slit or the like, the gas can be directly supplied to a wider area of the surface of the light emitting tube 21.

As shown in Figures 2 and 5, the cooling section 9 can be provided with multiple holding sections 9d for holding the barrier discharge lamp 2. The multiple holding sections 9d can be provided on the end face of the cooling section 9 opposite the frame 5 side. In a direction perpendicular to the face 5a of the frame 5, it is preferable that the face 9d1 of the multiple holding sections 9d opposite the frame 5 side is located in the area between the tube axis 21d of the arc tube 21 and the end 21e of the arc tube 21 opposite the frame 5 side. In this way, the arc tube 21 can be easily held, and the position of the barrier discharge lamp 2 can be stabilized.

The holding portion 9d may be, for example, plate-shaped. A pair of holding portions 9d are provided sandwiching the arc tube 21 in a direction perpendicular to the tube axis 21d of the arc tube 21. Ends of the pair of holding portions 9d on the arc tube 21 side may be brought into contact with the arc tube 21 via external electrodes 26.
The pair of holding portions 9d and the mounting portion 26a of the external electrode 26 are attached to the cooling portion 9 using fastening members such as screws.

6A and 6B are schematic perspective views illustrating a pair of holding portions.
For example, as shown in Fig. 6(a), a pair of holding parts 9d having the same shape can be provided. The holding part 9d can be plate-shaped and have at least one mounting hole 9d2 penetrating in the thickness direction. A side surface 9d3 of the holding part 9d on the side of the light emitting tube 21 can be curved. The radius of curvature of the side surface 9d3 can be the same as or slightly larger than half the value of the tube diameter of the light emitting tube 21. Alternatively, the side surface 9d3 can be an inclined surface approximating the radius of curvature, rather than a curved surface. The material of the holding part 9d can be, for example, a metal such as stainless steel, or a resin such as a fluororesin.

6B, it is possible to provide a holding portion 19 and a holding portion 29. The holding portion 19 can be provided facing the holding portion 29.
The holding part 19 has a plate-like shape and a surface 19d1 to be attached to the cooling part 9. A side surface 19d3 of the holding part 19 on the side of the light emitting tube 21 can be curved. The radius of curvature of the side surface 19d3 can be the same as or slightly larger than half the value of the tube diameter of the light emitting tube 21. Alternatively, the side surface 19d3 may be an inclined surface approximating the radius of curvature, rather than a curved surface. The holding part 19 can have at least one mounting hole 19d2 penetrating in the thickness direction. The mounting hole 19d2 has a shape extending in the direction in which the holding part 19 and the holding part 29 face each other, so that the distance between the side surface 19d3 of the holding part 19 and the side surface 29d3 of the holding part 29 can be adjusted.

The holding part 29 has a plate-like shape and a surface 29d1 that is attached to the cooling part 9. The side surface 29d3 of the holding part 29 on the side of the light-emitting tube 21 can be curved. The radius of curvature of the side surface 29d3 can be the same as or slightly larger than half the value of the tube diameter of the light-emitting tube 21. Alternatively, the side surface 29d3 may not be a curved surface, but may be an inclined surface that approximates the radius of curvature. The holding part 29 can have at least one mounting hole 29d2 that penetrates in the thickness direction. A convex part 29d4 can be provided on the periphery of the surface 29d1 on the side opposite to the side of the side surface 29d3. When the surface 29d1 is attached to the cooling part 9, the convex part 29d4 can be made to contact the side surface of the cooling part 9. In this way, the position of the holding part 29 relative to the cooling part 9 can be determined. Then, by moving the holding part 19 toward the holding part 29, the barrier discharge lamp 2 can be sandwiched between the holding part 19 and the holding part 29. This allows the holding position of the barrier discharge lamp 2 to be within a specified range, and the barrier discharge lamp 2 can be held more reliably.

The material of the holding portion 19 and the holding portion 29 can be, for example, a metal such as stainless steel or a resin such as a fluororesin.

At least one support part 12 can be provided. In the ultraviolet irradiation device 1 illustrated in FIG. 2, two support parts 12 are provided side by side in the direction along the tube axis 21d. In the direction along the tube axis 21d, the support part 12 can be provided at a position where the terminal cover 24 is provided.

As shown in FIGS. 1 and 2, the support portion 12 may be provided with, for example, an arm 12a, a bracket 12b, a shaft 12c, and a holding portion 12d.
The arm 12a may have a shape extending in a direction intersecting with the tube axis 21d of the light emitting tube 21. An axis 12c may be provided on one end side of the arm 12a. The arm 12a may be provided so as to be rotatable about the axis 12c. A member 12a1 for connecting to the holding part 12d may be provided on the other end side of the arm 12a. The arm 12a is preferably formed from a material that is heat resistant and has a small specific gravity. The arm 12a may be formed from, for example, fluororesin.

Bracket 12b supports shaft 12c. Bracket 12b can be provided, for example, on the side of positioning unit 3. Bracket 12b may also be provided, for example, on frame 5.

The shaft 12c may be cylindrical, for example. One end of the shaft 12c may be provided on the arm 12a, and the other end of the shaft 12c may be provided on the bracket 12b. In this case, one end of the shaft 12c may be fixed to the arm 12a, and the other end of the shaft 12c may be rotatably provided on the bracket 12b. Alternatively, one end of the shaft 12c may be rotatably provided on the arm 12a, and the other end of the shaft 12c may be fixed to the bracket 12b.

The holding portion 12d detachably holds the end of the arm 12a opposite to the side where the shaft 12c is provided. The holding portion 12d can be, for example, a ball catch, a lock, or a snap lock. The holding portion 12d can be provided, for example, on the side of the positioning portion 3 opposite to the side where the bracket 12b is provided. The holding portion 12d may also be provided, for example, on the frame 5.

1, when the end of the arm 12a is held by the holding portion 12d, the arm 12a can be brought into contact with the terminal cover 24 of the barrier discharge lamp 2. Also, a small gap may be provided between the arm 12a and the terminal cover 24 of the barrier discharge lamp 2. In other words, when one end of the arm 12a is held by the holding portion 12d, the arm 12a is provided below the terminal cover 24.
In this way, even if the barrier discharge lamp 2 falls off the holding portion 9d, the barrier discharge lamp 2 can be prevented from falling onto the target object.

When removing the barrier discharge lamp 2, the holding portion 9d is removed while the end of the arm 12a is held by the holding portion 12d. Then, as shown in FIG. 1, the holding of the end of the arm 12a is released and the arm 12a is rotated. By rotating the arm 12a, the arm 12a can be retracted from below the barrier discharge lamp 2, so that the barrier discharge lamp 2 can be easily removed.

When mounting the barrier discharge lamp 2, the barrier discharge lamp 2 is mounted on the positioning part 3 with the arm 12a retracted from below the barrier discharge lamp 2. Thereafter, as shown in Fig. 1, the arm 12a is rotated and the end of the arm 12a is held by the holding part 12d. Next, the holding part 9d is attached to the cooling part 9 using a fastening member such as a screw, so that the barrier discharge lamp 2 is held by the holding part 9d.
Holding of the arm 12a by the holding portion 12d is easier than holding of the barrier discharge lamp 2 by the holding portion 9d. Therefore, the barrier discharge lamp 2 is prevented from falling, and the installation work of the barrier discharge lamp 2 can be made easier.

The support portion 12 can be omitted. However, if the support portion 12 is provided, it is possible to prevent the barrier discharge lamp 2 from falling when the barrier discharge lamp 2 is attached or detached.

Figure 7 is a schematic side view illustrating an ultraviolet irradiation device 1a according to another embodiment. As shown in Figure 7, the ultraviolet irradiation device 1a can be provided with a barrier discharge lamp 2, a positioning unit 3, a positioning unit 4, a frame 5, a lighting circuit 6, a gas supply unit 7, a controller 8, a cooling unit 9, a support unit 12, and a temperature control unit 10.

As described above, in the gap 9a between the cooling part 9 and the external electrode 26, nitric acid may be generated depending on the conditions of the gap 9a. If nitric acid is generated, the optical characteristics of the arc tube 21 may deteriorate, the external electrode 26 may be damaged, or the object to be irradiated with ultraviolet light may be damaged. As described above, the gas supplied to the gap 9a may be a gas that does not contain oxygen, or a gas that has a lower oxygen concentration than air. However, in general, the barrier discharge lamp 2 is installed in the atmosphere. Therefore, it is possible that air around the barrier discharge lamp 2 may enter the gap 9a. If air enters the gap 9a, the above-mentioned chemical reaction may occur, and nitric acid may be generated.
Therefore, the ultraviolet irradiating device 1 a is provided with a temperature control unit 10 .

The temperature control unit 10 controls at least one of the temperature of the cooling unit 9 and the temperature of the gas supplied to the gap 9a. For example, the temperature control unit 10 can be a heater provided in at least one of the cooling unit 9 and the gas supply unit 7.

For example, the temperature control unit 10 can be a heater provided between the cooling unit 9 and the frame 5, or a heater provided inside the cooling unit 9. In this case, a temperature sensor can be provided in the cooling unit 9, and the controller 8 can control the temperature control unit 10 based on a signal from the temperature sensor.

For example, the temperature control unit 10 can be a heater provided in the pipe 74 or the like. In this case, a temperature sensor can be provided in the pipe 74 or the cooling unit 9, and the controller 8 can control the temperature control unit 10 based on a signal from the temperature sensor.

Here, the sublimation temperature of dinitrogen pentoxide is 32.4° C. Therefore, by setting the temperature of the gas in gap 9a to 32.4° C. or higher, dinitrogen pentoxide can be prevented from becoming a solid. If dinitrogen pentoxide is in a gaseous state, it becomes easy to discharge dinitrogen pentoxide together with the gas supplied to gap 9a by gas supply unit 7.
Furthermore, dinitrogen pentoxide is decomposed into nitrogen dioxide and oxygen when heated to about 45° C. to 50° C. Therefore, if the temperature of the gas in gap 9a is set to 45° C. or higher, the generation of nitric acid can be suppressed.

In this case, if the temperature of the cooling section 9, or the temperature of the cooling section 9 and the frame 5, is set to 32.4°C or higher, the dinitrogen pentoxide will be easily sublimated and discharged to the outside of the gap 9a, thereby suppressing the generation of nitric acid.
Note that the sublimation of dinitrogen pentoxide can be promoted and the production of nitric acid can be further suppressed by increasing the temperature of the cooling section 9 or the temperature of the cooling section 9 and the frame 5. According to the findings of the present inventors, the production of nitric acid can be further suppressed by setting the temperature of the cooling section 9 or the temperature of the cooling section 9 and the frame 5 to 35° C. or higher.

As described above, dinitrogen pentoxide is decomposed into nitrogen dioxide and oxygen when heated to about 45° C. to 50° C. Therefore, if the temperature of cooling unit 9, or the temperature of cooling unit 9 and frame 5, is set to 45° C. or higher, the generation of nitric acid can be effectively suppressed.
However, if the temperature of the cooling section 9, or the temperature of the cooling section 9 and the frame 5, is set to 45° C. or higher, there is a concern that cooling of the arc tube 21 and the external electrode 26 may be inhibited.

According to the findings of the present inventors, if the temperature of the cooling section 9, or the temperature of the cooling section 9 and the frame 5, is not less than 35° C. and not more than 40° C., the cooling effect of the arc tube 21 and the external electrode 26 can be maintained, and the production of nitric acid can be suppressed.
That is, the temperature control unit 10 preferably sets the temperature of the cooling unit 9, or the temperature of the cooling unit 9 and the frame 5, to 32.4°C or higher and 40°C or lower, and more preferably sets the temperature of the cooling unit 9 or higher and 40°C or lower.

Fig. 8 is a schematic side view illustrating an ultraviolet irradiation device 1b according to another embodiment. As shown in Fig. 8, the ultraviolet irradiation device 1b can be provided with a barrier discharge lamp 2, a positioning unit 3, a positioning unit 4, a frame 5, a lighting circuit 6, a gas supply unit 7, a controller 8, a cooling unit 9, and a cover 11. In addition, a support unit 12 can be further provided, similarly to the ultraviolet irradiation device 1 described above. That is, the ultraviolet irradiation device 1b can be provided with the support unit 12 in addition to the ultraviolet irradiation device 1.
In order to avoid complication, the support portion 12 is omitted in FIG.

The cover 11 may have a window 11a and a mounting member 11b.
The window 11a has a plate shape and can be provided on the side of the barrier discharge lamp 2 opposite to the frame 5 side. That is, the window 11a can be provided between the barrier discharge lamp 2 and an object to be irradiated with ultraviolet light. The window 11a can be made of a material that transmits ultraviolet light. The window 11a can be made of, for example, quartz glass or a fluororesin that transmits ultraviolet light. In particular, in the case of a barrier discharge lamp 2 filled with xenon that emits ultraviolet light at 172 nm, the window 11a can be made of synthetic quartz glass that transmits ultraviolet light at 172 nm.

One end of the mounting member 11b can be attached to the side of the frame 5, for example, using a fastening member such as a screw. The window 11a can be attached to the other end of the mounting member 11b, for example, using a fastening member such as a screw.

Here, when ultraviolet light is irradiated onto an object, components of the object may evaporate. If the evaporated components of the object adhere to the light emitting tube 21, the illuminance of the ultraviolet light irradiated from the barrier discharge lamp 2 may decrease.

Since the ultraviolet irradiation device 1b is provided with a cover 11 (window 11a), it is possible to prevent the evaporated components of the object from adhering to the arc tube 21. In addition, the gas supplied to the gap 9a between the cooling unit 9 and the external electrode 26 flows into the space between the barrier discharge lamp 2 and the window 11a. Therefore, it is possible to prevent the evaporated components of the object around the ultraviolet irradiation device 1b from entering the space between the barrier discharge lamp 2 and the window 11a. That is, the gas flowing out from the gap 9a can be reused as a purge gas. For example, in the case of a barrier discharge lamp 2 filled with xenon that emits ultraviolet rays of 172 nm, in order to prevent the attenuation of ultraviolet rays in the space from the arc tube 21 to the window 11a, it is appropriate to use an inert gas, such as nitrogen or argon, as the cooling gas.
Although the evaporated components of the object adhere to the window 11a, since the window 11a is merely a plate-like body, it can be easily removed for replacement or cleaning.
Even if the above-mentioned nitric acid is generated and drips from the barrier discharge lamp 2, the dripped nitric acid can be received by the cover 11 (window 11a). Therefore, it is possible to more reliably prevent the nitric acid from adhering to the object. Furthermore, by completely purging the space between the barrier discharge lamp 2 and the window 11a with the inert gas supplied, it is possible in principle to prevent the generation of nitric acid.

The ultraviolet irradiation device 1b according to the present embodiment can suppress a decrease in the illuminance of the ultraviolet light irradiated from the barrier discharge lamp 2, and can also facilitate maintenance.
Moreover, even if the distance between the barrier discharge lamp 2 and the object is reduced, it is possible to prevent the evaporated components of the object from adhering to the arc tube 21. Therefore, it is possible to increase the illuminance of the ultraviolet light irradiated on the object.

FIG. 9 is a schematic side view illustrating an ultraviolet irradiation device 1c according to another embodiment.
9, the ultraviolet irradiation device 1c can be provided with a barrier discharge lamp 2, a positioning unit 3, a positioning unit 4, a frame 5, and a support unit 112. Also, like the ultraviolet irradiation device 1 illustrated in FIG. 1, a lighting circuit 6, a gas supply unit 7, a controller 8, and a cooling unit 9 can be provided.
The ultraviolet irradiation device 1 c may be provided with a support portion 112 instead of the support portion 12 provided in the ultraviolet irradiation device 1 .

The above-mentioned support part 12 is provided with an arm 12a that supports three barrier discharge lamps 2 together. In contrast, the support part 112 is provided with an arm 112a that supports one barrier discharge lamp 2. The holding part 12d detachably holds the end of the arm 112a on the opposite side to the side where the shaft 12c is provided.
In this way, for example, when one barrier discharge lamp 2 is attached or detached, the other barrier discharge lamps 2 can be held. This makes maintenance and assembly easier. In addition, the length of the arm 112a can be shortened, so the space required to release the arm 112a can be reduced. In addition, the distance between the ultraviolet irradiation device 1c and the object to be irradiated with ultraviolet light can be shortened.

Although several embodiments of the present invention have been illustrated above, these embodiments are presented as examples 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, modifications, etc. can be made without departing from the gist of the invention. These embodiments and their variations are included within the scope and gist of the invention, as well as within the scope of the invention and its equivalents described in the claims. Furthermore, the above-mentioned embodiments can be implemented in combination with each other.

1 UV irradiation device, 1a UV irradiation device, 1b UV irradiation device, 1c UV irradiation device, 2 Barrier discharge lamp, 3 Positioning portion, 3a Flat surface, 4 Positioning portion, 5 Frame, 6 Lighting circuit, 7 Gas supply portion, 8 Controller, 9 Cooling portion, 9a Gap, 9b Surface, 9c Hole, 9c3 Discharge hole, 9d Holding portion, 10 Temperature control portion, 11 Cover, 11a Window, 12 Support portion, 12a Arm, 12d Holding portion, 19 Holding portion, 21 Arc tube, 21d Tube axis, 22 Internal electrode, 24 Terminal cover, 24a Flat surface, 26 External electrode, 26a Mounting portion, 29 Holding portion

Claims (3)

A cylindrical arc tube having an internal space filled with a rare gas;
an internal electrode having a coil disposed in the internal space;
an external electrode provided on the outside of the light emitting tube;
a cooling portion provided outside the external electrode via a gap;
a terminal cover provided at an end of the light emitting tube and having a first flat surface on a side surface;
a positioning portion having a hole in which the terminal cover is provided;
Equipped with
An ultraviolet irradiation device, wherein a second flat surface capable of coming into contact with the first flat surface of the terminal cover is provided on the inner wall surface of the hole. The first flat surface is provided in a pair so as to be parallel to each other,
2. The ultraviolet irradiation device according to claim 1, wherein the second flat surface comprises a pair of second flat surfaces arranged parallel to each other. The support unit further includes a support portion having a rotatable arm and a holding portion that detachably holds one end of the arm,
3. The ultraviolet irradiation device according to claim 1, wherein when one end of the arm is held by the holding portion, the arm is provided below the terminal cover.

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