Irradiation equipment, plasma irradiation device, irradiation tube

Abstract

This irradiation equipment (10) comprises: an electrode that generates plasma by voltage being applied; and an introduction path (3) that communicates with an irradiation port (1c) that irradiates activated gas on an irradiation object, and extends from the tip of the irradiation port (1c) side of the electrode to the irradiation port (1c). The introduction path (3) has a reduced diameter part (3B) in which the diameter becomes smaller toward the guiding direction in which the activated gas is guided to the irradiation object, and has a non-conductive part constituted by a non-metal material on at least a portion of an inner surface (3b) of the reduced diameter part (3B).

Description

[Technical Field]

[0001] The present invention relates to an irradiation device, a plasma irradiation apparatus equipped with an irradiation device, and an irradiation tube. This application claims priority based on Japanese Patent Application No. 2020-153089, filed in Japan on September 11, 2020, and the contents of that application are incorporated herein by reference. [Background technology]

[0002] Conventionally, plasma irradiation devices are known for medical applications such as dental treatment. Plasma irradiation devices heal wounds and other affected areas (targets of irradiation) by irradiating them with plasma or an active gas. The active gas is generated by plasma in the discharge section of the irradiation device. The plasma irradiation device blows the short-lived active gas generated in the discharge section out of the tip of the irradiation device towards the target of irradiation as a gas stream. In order to promote healing of the target of irradiation, it is necessary to efficiently deliver the generated active gas to the affected area. Various shapes have been considered for the nozzle provided at the tip of the irradiation device of a plasma irradiation apparatus (see, for example, Patent Document 1). According to the invention of Patent Document 1, plasma can be irradiated according to the conditions of the object to be irradiated. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2013-128681 [Overview of the project] [Problems that the invention aims to solve]

[0004] In a plasma irradiation device, it is believed that the active gas can be efficiently delivered to the affected area by lengthening the nozzle and bringing the irradiation port at the nozzle tip closer to the target of irradiation, or by reducing the diameter of the irradiation port at the nozzle tip and increasing the ejection speed of the active gas. However, in plasma irradiation devices, simply lengthening the nozzle or reducing the aperture diameter of the irradiation port presented a problem: the number of active species in the active gas decreased.

[0005] The present invention has been made in view of the above circumstances, and aims to provide an irradiation device that can increase the density of active species contained in the active gas irradiated onto the irradiated object, a plasma irradiation device equipped with the irradiation device, and an irradiation tube used in the irradiation device. [Means for solving the problem]

[0006] As a result of diligent research by the inventors, it was found that if the inner surface of the flow channel in the irradiation device that comes into contact with the active gas is made of metal, the active gas generated by the plasma contains charged particles, so when the active gas comes into contact with the metal, it becomes deactivated, and the amount of active species transported to the target decreases.

[0007] To solve the above problems, the present invention has the following aspects. [1] An electrode that generates plasma when a voltage is applied, It comprises an irradiation port for irradiating the target with an active gas, and an introduction path extending from the tip of the electrode on the irradiation port side to the irradiation port, The introduction path has a reduced diameter section in which the diameter decreases in the direction of discharge for guiding the active gas to the irradiation target, An irradiation device having a non-conductive portion made of a non-metallic material on at least a portion of the inner surface of the reduced diameter portion. [2] Furthermore, the irradiation tube having the irradiation port is provided, The irradiation tube has a detachable attachment mechanism, The irradiation device according to [1], wherein the diameter-reduced portion is formed in the flow path inside the irradiation tube. [3] The electrical resistivity of the nonmetallic material is 10 6 Ωm or more 10 25 It is less than or equal to Ωm, and 10 11 Ωm or more 10 25 Preferably, it is Ωm or less, 10 14 Ωm or more 10 25The irradiation device described in [1] is more preferably Ωm or less. [4] The irradiation device according to any one of [1] to [3], wherein at least the inner surface of the reduced diameter portion is made of a nonmetallic material. [5] The plasma generating section including the electrodes comprises an outer cylindrical member covering the plasma generating section and an irradiation tube protruding from the outer cylindrical member and leading the active gas to the irradiated object, The irradiation device according to any one of [1] to [4], wherein the introduction path includes a flow path inside the irradiation tube. [6] The irradiation device described in [5], wherein the irradiation tube is bent. [7] The irradiation device according to [5] or [6], wherein the irradiation tube has a detachable attachment mechanism, and the attachment mechanism is detachable from the outer cylindrical member. [8] The plasma generating unit comprises a tubular dielectric, an internal electrode disposed within the tubular dielectric and having a surface exposed to a plasma generating gas, and an external electrode disposed on the outer circumference of the internal electrode, The irradiation device according to any one of [5] to [7], wherein the outer diameter of the internal electrode is larger than the inner diameter of the reduced diameter portion. [9] The irradiation device according to any one of [1] to [8], wherein the inner diameter of the introduction passage is greater at the rear end than at the front end.

[10] The irradiation device according to any one of [1] to [8], wherein the inner diameter of the introduction passage is gradually reduced from the rear end to the front end.

[11] The irradiation device according to any one of [1] to [8], wherein the inner diameter of the introduction passage decreases from the rear end to the front end.

[12] The irradiation device according to any one of [1] to

[11] , wherein 50% or more, preferably 80% or more, and most preferably 100% of the total surface area of ​​the inner surface of the reduced diameter portion is covered with the non-conductive portion.

[13] Having a cowling (housing) including a head section and a torso section, The irradiation port is provided on the tip side of the head portion, The electrode is housed within the body portion, The irradiation device according to any one of [1] to

[12] , wherein at least a portion of the introduction path is provided within the head portion. A plasma irradiation device comprising an irradiation device according to any one of

[14] [1] to

[13] .

[15] An electrode that generates plasma when a voltage is applied, A introduction path that communicates with an irradiation port for irradiating an active gas to an irradiation target and extends from the tip of the electrode on the irradiation port side to the irradiation port, The introduction path has a diameter-reducing portion whose diameter becomes smaller toward the direction of导出 the active gas to the irradiation target, An irradiation tube for use in an irradiation device, having a non-conductive portion made of a non-metallic material on at least a part of the inner surface of the diameter-reducing portion. [Effect of the Invention]

[0008] According to the present invention, an irradiation device capable of increasing the density of active species contained in an active gas irradiated to an irradiation target, a plasma irradiation device including the irradiation device, and an irradiation tube can be provided. [Brief Description of the Drawings]

[0009] [Figure 1] It schematically shows an irradiation device according to an embodiment of the present invention, and is a cross-sectional view of a plane along the axis in the irradiation device. [Figure 2] It schematically shows an irradiation device according to an embodiment of the present invention, and is a cross-sectional view of a plane along the axis in the irradiation device. [Figure 3] It schematically shows an irradiation device according to an embodiment of the present invention, and is a cross-sectional view of a plane along the axis in the irradiation device. [Figure 4] It schematically shows an irradiation device according to an embodiment of the present invention, and is a cross-sectional view of a plane along the axis in the irradiation device. [Figure 5] It schematically shows an irradiation device according to an embodiment of the present invention, and is a cross-sectional view of a plane along the axis in the irradiation device. [Figure 6] It schematically shows an irradiation device according to an embodiment of the present invention, and is a cross-sectional view of a plane along the axis in the irradiation device. [Figure 7] It schematically shows an irradiation device according to an embodiment of the present invention, and is a cross-sectional view of a plane along the axis in the irradiation device. [Figure 8] This is a schematic diagram of an irradiation device according to one embodiment of the present invention, and is a cross-sectional view of a plane along the axis of the irradiation device. [Figure 9] This is a schematic diagram of an irradiation device according to one embodiment of the present invention, and is a cross-sectional view of a plane along the axis of the irradiation device. [Figure 10] This is a schematic diagram of an irradiation device according to one embodiment of the present invention, and is a cross-sectional view of a plane along the axis of the irradiation device. [Figure 11] This is a schematic diagram of an irradiation device according to one embodiment of the present invention, and is a cross-sectional view of a plane along the axis of the irradiation device. [Figure 12] This is a schematic diagram showing a plasma irradiation device according to one embodiment of the present invention. [Figure 13] This is a block diagram showing a schematic configuration of a plasma irradiation device according to one embodiment of the present invention. [Figure 14] This figure shows the measurement results of the density of hydroxyl radicals contained in the activated gas blown out from the irradiation port in the examples and comparative examples. [Figure 15] This figure shows the measurement results of the density of singlet oxygen contained in the activated gas blown out from the irradiation port in the examples and comparative examples. [Figure 16] This figure shows the measurement results of the density of singlet oxygen contained in the activated gas blown out from the irradiation port in the examples and comparative examples. [Modes for carrying out the invention]

[0010] The following description will explain, with reference to the drawings, an irradiation device and a plasma irradiation apparatus equipped with the irradiation device according to embodiments of the present invention. Note that, for convenience, the drawings used in the following description show enlarged versions of characteristic parts, and the dimensional ratios of each component may differ from those of the actual components. Furthermore, the materials, dimensions, etc., exemplified in the following description are merely examples, and the present invention is not limited to them. They can be modified as appropriate without altering the essence of the invention.

[0011] The irradiation device of the present invention generates plasma and irradiates the target object with the activated gas produced by the generated plasma from the irradiation port. It is believed that when the activated gas, which contains activated species generated by the plasma, collides with a metal wall surface, electrons and other elements are trapped, and the concentration of activated species decreases. In this specification, "active gas" refers to a highly chemically active gas containing any of the following: active species such as radicals, excited atoms, excited molecules, electrons, ions, etc.

[0012] [Irradiation device] Figures 1 to 5 schematically show an irradiation device according to one embodiment of the present invention, and are cross-sectional (longitudinal) views of a plane along the axis of the irradiation device. As shown in Figure 1, the irradiation device 10 of this embodiment comprises electrodes (internal electrodes 6, external electrodes 7) that generate plasma when a voltage is applied, and an introduction path 3 that communicates with an irradiation port 1c for irradiating an irradiated object with an active gas and extends from the tip of the electrodes on the irradiation port 1c side to the irradiation port 1c. The irradiation device 10 of this embodiment comprises a long cowling 1 (housing), a plasma generation unit 2 that includes the electrodes (internal electrodes 6, external electrodes 7) and generates plasma when a voltage is applied via the electrodes, and an introduction path 3 that guides the irradiated object with the active gas generated by the plasma generation unit 2 to the irradiation port 1c.

[0013] The cowling 1 comprises a cylindrical body portion 1a and a head portion 1b that closes the tip of the body portion 1a. The body portion 1a houses the plasma generating unit 2. The body portion 1a is not limited to a cylindrical shape, but may also be a polygonal cylindrical shape such as a square tube, hexagonal tube, or octagonal tube. The head portion 1b has an irradiation port 1c at its tip for irradiating the target with an active gas. The head portion 1b has a part of the introduction passage 3 (the reduced diameter portion 3B of the introduction passage 3) extending in the direction of the pipe axis O1 inside. The pipe axis O1 is the pipe axis of the body portion 1a. The fuselage section 1a may be equipped with an operating switch 4 (operating section) on its outer surface.

[0014] As shown in Figure 1, the plasma generation unit 2 comprises a tubular dielectric 5 (dielectric), an internal electrode 6, and an external electrode 7. The tubular dielectric 5 is a cylindrical member extending in the direction of the tube axis O1. The tubular dielectric 5 extends in the direction of the tube axis O1 and is a region that includes the internal electrode 6 and the external electrode 7, and has a flow path 8 through which the plasma generation gas and the active gas generated by the plasma flow. The flow path 8 and the introduction path 3 are in communication. The introduction path 3 is in communication with the irradiation port 1c that irradiates the target with the active gas, and is a flow path that extends from the tip of the electrode (internal electrode 6 or external electrode 7; for example, the internal electrode 6 in Figure 1) on the irradiation port 1c side (for example, the tip 6a of the internal electrode 6 in Figure 1) to the irradiation port 1c. The tube axis O1 of the tubular dielectric 5 is the same as the tube axis O1 of the cowling 1. The introduction path 3 is provided inside the head portion 1b of the cowling 1 so as to extend in the direction of the tube axis O1. The flow path 8 is located inside the body portion 1a of the cowling 1, from the tip of the electrode (internal electrode 6 or external electrode 7; for example, internal electrode 6 in Figure 1) on the irradiation port 1c side (for example, the tip 6a of the internal electrode 6 in Figure 1) to the rear end. Note that the introduction path 3 does not specify a location, but rather refers to a structure that surrounds the space connecting the plasma generation unit 2 and the irradiation port 1c. The plasma generation unit 2 comprises a tubular dielectric 5, an internal electrode 6 disposed within the tubular dielectric 5 and having a surface exposed to the plasma generation gas, and an external electrode 7 disposed on the outer circumference of the internal electrode 6. In other words, the plasma generation unit 2 includes an internal electrode 6 disposed within the flow path 8. The internal electrode 6 is a substantially cylindrical member extending in the direction of the tube axis O1. The internal electrode 6 is spaced apart from the inner surface of the tubular dielectric 5. The internal electrode 6 has a surface exposed to the plasma generation gas. The outer diameter d1 of the internal electrode 6 is larger than the diameter d2 of the reduced diameter portion 3B of the introduction path 3 (the inner diameter when the head portion 1b is considered as a tube). Here, the ratio of d1 to d2 (d1 / d2) is preferably 0.1 or more and 100 or less, more preferably 1 or more and 10 or less, and even more preferably 3 or more and 7 or less. When this ratio d1 / d2 is within the above range, it becomes possible to deliver the active gas to the irradiated target more efficiently. A portion of the outer surface of the tubular dielectric 5 is provided with an external electrode 7 that runs along the internal electrode 6. The external electrode 7 is an annular electrode that runs around the outer surface of the tubular dielectric 5. The tubular dielectric 5, the internal electrode 6, and the external electrode 7 are positioned concentrically around the tube axis O1.

[0015] In this embodiment, the outer circumferential surface of the internal electrode 6 and the inner circumferential surface of the external electrode 7 face each other with the tubular dielectric 5 in between. The region formed by the outer circumferential surface of the internal electrode 6 and the inner circumferential surface of the external electrode 7, which face each other with the tubular dielectric 5 in between, is the discharge section 2A.

[0016] In this embodiment, the introduction passage 3 has a first introduction passage 3A with the same diameter as the flow path 8, and a reduced-diameter section (second introduction passage) 3B whose diameter decreases in the direction of discharge (direction from flow path 8 towards introduction passage 3) for guiding the active gas to the irradiation target. The tip of the irradiation device 10 on the discharge direction side is the tip of the irradiation device 10 (cowling 1), and the opposite side is the rear end of the irradiation device 10 (cowling 1). More specifically, as shown in Figure 2, the diameter of the reduced diameter portion 3B may be larger at the rear end than at the front end. In this example, the inner diameter d5 of the irradiation port 1c is smaller than the diameter d4 of the rear end of the reduced diameter portion 3B (the end face on the flow path 8 side of the head portion 1b) due to the wall extending inward at the front end of the reduced diameter portion 3B. That is, the diameter d4 of the rear end of the reduced diameter portion 3B is larger than the diameter d5 of the front end of the reduced diameter portion 3B (irradiation port 1c). Here, the ratio of d4 to d5 (d4 / d5) is preferably greater than 1 and 100 or less, more preferably greater than 1 and 10 or less, and even more preferably greater than 1 and 5 or less. When this ratio d4 / d5 is within the above range, it becomes possible to deliver the active gas to the affected area more efficiently. Furthermore, as shown in Figure 3, the diameter of the reduced diameter portion 3B may decrease in stages from the rear end to the front end. In this example, the reduced diameter portion 3B has, in order from the rear end to the front end, a first reduced diameter portion 3B1, a second reduced diameter portion 3B2, and a third reduced diameter portion 3B3. That is, the diameter of the first reduced diameter portion 3B1 is larger than the diameter of the second reduced diameter portion 3B2, and the diameter of the second reduced diameter portion 3B2 is larger than the diameter of the third reduced diameter portion 3B3. In the example shown in Figure 3, a case is illustrated in which the reduced diameter portion 3B is composed of three parts that decrease in stages from the rear end to the front end, but this embodiment is not limited to this. In this embodiment, the reduced diameter portion 3B may be composed of two or more parts that decrease in stages from the rear end to the front end. Furthermore, as shown in Figure 4, the diameter of the reduced-diameter section 3B may decrease from the rear end to the front end. That is, the reduced-diameter section 3B may have a tapered shape. In the reduced-diameter section 3B, the diameter d6 at the rear end of the first reduced-diameter section 3B1 is the largest, and the diameter d7 at the front end (irradiation port 1c) of the second reduced-diameter section 3B2 is the smallest. Here, the ratio of d6 to d7 (d6 / d7) is preferably greater than 1 and 100 or less, more preferably greater than 1 and 10 or less, and even more preferably greater than 1 and 5 or less. When this ratio d6 / d7 is within the above range, it becomes possible to deliver the active gas to the affected area more efficiently.

[0017] Furthermore, as shown in Figure 5, the diameter-reducing section 3B has a first diameter-reducing section 3B1 which has a tapered shape that reduces in diameter from the rear end to the front end, and a second diameter-reducing section 3B2 which is provided closer to the front end than the first diameter-reducing section 3B1 and has a constant diameter along the pipe axis O1 direction. In this example, at the base end 1e, the diameter of the first introduction passage 3A and the diameter of the diameter-reducing section 3B are equal.

[0018] In this embodiment, the plasma generation unit 2 generates plasma by dielectric barrier discharge. The plasma generation unit 2 generates plasma using, for example, nitrogen.

[0019] The plasma generating unit 2 is detachable from the cowling 1. The plasma generating unit 2 can be pulled out from the cowling 1 in the direction of the tube axis O1, for example. For example, after the cowling 1 is disassembled into a body portion 1a and a head portion 1b, the plasma generating unit 2 may be configured to be pulled out in front of the body portion 1a (where the head portion 1b side is the front and the body portion 1a side is the rear along the direction of the tube axis O1). For example, if the plasma generating unit 2 is damaged, the plasma generating unit 2 can be detached from the cowling 1, and a new plasma generating unit 2 can be attached to the cowling 1. In this case, the new plasma generating unit 2 can be inserted into the cowling 1 in the direction of the pipe axis O1.

[0020] In this embodiment, as shown in Figures 1 to 5, the irradiation device 10 may have an outer cylindrical member 9 that covers the plasma generation unit 2. The outer cylinder member 9 is fitted onto the cowling 1 from the outside. The outer cylinder member 9 is integrally formed with a portion that covers the body portion 1a of the cowling 1 and a portion that covers the head portion 1b of the cowling 1. The outer cylinder member 9 is detachably attached to the cowling 1. In order to improve the detachability of the outer cylinder member 9, irregularities may be provided on the inner surface of the outer cylinder member 9. By providing irregularities, the contact area between the outer cylinder member 9 and the cowling 1 can be reduced, thereby reducing frictional resistance during attachment and detachment.

[0021] From the viewpoint of insulating the external electrodes 7, the material of the body portion 1a is preferably an insulating material. The body portion 1a may also be a multilayer structure having an insulating material and a layer of metallic material on its surface. There are no particular restrictions on the size of the torso 1a; it can be made to a size that is easy to grasp with the fingers.

[0022] The material of the head portion 1b is not particularly limited and may or may not be insulating. The material of the head portion 1b is preferably one with excellent wear resistance and corrosion resistance. Examples of materials with excellent wear resistance and corrosion resistance include metals such as stainless steel and non-metallic materials. The materials of the body portion 1a and the head portion 1b may be the same or different.

[0023] In this embodiment, at least a part of the inner surface 3b of the diameter-reduced portion 3B has a non-conductive portion made of a non-metallic material. The entire head portion 1b may be a non-conductive portion made of a non-metallic material, or at least a part of the inner surface 3b of the diameter-reduced portion 3B in the head portion 1b may have a non-conductive portion made of a non-metallic material. Here, having a non-conductive portion in at least a part means that 50% or more of the total area of the inner surface 3b of the diameter-reduced portion 3B is covered with the non-conductive portion. Also, in order to surely obtain the effects described later, it is preferable that 80% or more of the total area of the inner surface 3b of the diameter-reduced portion 3B is covered with the non-conductive portion, and most preferably 100% is covered with the non-conductive portion. Further, the thickness of the non-conductive portion is preferably 1 nm or more and 10 mm or less, more preferably 1 μm or more and 5 mm or less, and most preferably 0.5 μm or more and 2 mm or less.

[0024] The electrical resistivity of the non-metallic material is 10 6 Ωm or more and 10 25 Ωm or less, preferably 10 11 Ωm or more and 10 25 Ωm or less, more preferably 10 14 Ωm or more and 10 25 Ωm or less, even more preferably. By the electrical resistivity being not less than the lower limit value, electrons are trapped on the inner surface 3b of the diameter-reduced portion 3B, thereby suppressing the deactivation of active species. By the electrical resistivity being not more than the upper limit value, the material can be easily obtained. Also, by the electrical resistivity being 10 14 Ωm or more, the deactivation of active species due to electrons being trapped on the inner surface 3b of the diameter-reduced portion 3B can be more suppressed. The non-metallic material is not particularly limited, and examples thereof include insulators such as resins and ceramics. Examples of the resin include polyethylene, polypropylene, polyether ether ketone (PEEK), unirate, fluororesin, and the like. Examples of the ceramics include alumina. Furthermore, multiple nonmetallic materials may be used in combination, as long as the aforementioned electrical resistivity is achieved for the non-conductive portion as a whole.

[0025] As the material for the tubular dielectric 5, dielectric materials used in known plasma devices can be applied. Examples of materials for the tubular dielectric 5 include glass, ceramics, and synthetic resins. A higher dielectric constant of the tubular dielectric 5 is preferable.

[0026] The internal electrode 6 comprises a shaft portion extending in the direction of the pipe axis O1 and threads on the outer surface of the shaft portion. The shaft portion may be solid or hollow. A solid shaft portion is preferred. A solid shaft portion is easier to process and enhances mechanical durability. The threads of the internal electrode 6 are helical threads that revolve around the circumferential direction of the shaft portion. The shape of the internal electrode 6 is similar to that of a male screw. The height of the threads of the internal electrode 6 can be appropriately determined considering the outer diameter d1 of the internal electrode 6. The internal electrode 6 has threads on its outer surface, which locally strengthens the electric field at the thread tips and lowers the discharge initiation voltage. As a result, plasma can be generated and maintained with low power. Furthermore, the internal electrode 6 does not need to have irregularities such as screw threads on its outer surface. In other words, the internal electrode 6 may be a cylindrical member without any irregularities on its outer surface.

[0027] The material of the internal electrode 6 is not particularly limited as long as it is a conductive material; metals that can be used for electrodes in known plasma devices can be applied. Examples of materials for the internal electrode 6 include metals such as stainless steel, copper, and tungsten, as well as carbon.

[0028] For the internal electrode 6, specifications equivalent to those of JIS B 0205:2001 metric threads (M2, M2.2, M2.5, M3, M3.5, etc.), JIS B 2016:1987 metric trapezoidal threads (Tr8×1.5, Tr9×2, Tr9×1.5, etc.), and JIS B 0206:1973 unified coarse threads (No.1-64UNC, No.2-56UNC, No.3-48UNC, etc.) are preferable. Specifications equivalent to these standard products offer cost advantages.

[0029] The material of the external electrode 7 is not particularly limited as long as it is a conductive material; metals known to be used for electrodes in plasma devices can be applied. Examples of materials for the external electrode 7 include stainless steel, copper, tungsten, and carbon.

[0030] The outer cylinder member 9 is preferably made of a metal material, from the viewpoint of blocking electromagnetic waves generated from the plasma generation unit 2 and electrical wiring (cables, etc.). Examples of metal materials include stainless steel, aluminum, and copper.

[0031] According to the irradiation device 10 of this embodiment, since the introduction path 3 has a diameter-reducing section 3B in the direction of discharge, the flow velocity of the activated gas blown out from the irradiation port 1c is increased, and the blowing speed of the activated species is increased, thereby increasing the amount of activated species that reach the target without being deactivated. Furthermore, since at least a part of the inner surface 3b of the diameter-reducing section 3B has a non-conductive section made of a non-metallic material, the deactivation of the activated gas inside the introduction path 3 can be suppressed. Furthermore, since at least a part of the inner surface 3b of the diameter-reducing section 3B has a non-conductive section made of a non-metallic material, the deterioration of the activated species inside the introduction path 3 can be suppressed. As a result, the density of activated species contained in the activated gas irradiated onto the target can be increased. Note that irradiating with activated gas can be rephrased as blowing (transporting) the activated gas toward the target.

[0032] According to the irradiation device 10 of this embodiment, by having at least the inner surface 3b of the reduced diameter portion 3B made of a non-metallic material, the effect of suppressing the deactivation of the active gas inside the introduction path 3 can be improved.

[0033] According to the irradiation device 10 of this embodiment, the diameter-reducing section 3B has a first diameter-reducing section 3B1 having a tapered shape that reduces in diameter from the rear end to the front end, and a second diameter-reducing section 3B2 provided closer to the front end than the first diameter-reducing section 3B1 and having a constant diameter along the direction of the pipe axis O1. As a result, turbulence and other issues do not occur inside the introduction passage 3, and the flow velocity of the active gas blown out from the irradiation port 1c can be increased.

[0034] According to the irradiation device 10 of this embodiment, the plasma generation unit 2 includes a tubular dielectric 5, an internal electrode 6 disposed inside the tubular dielectric 5 and having a surface exposed to the plasma generation gas, and an external electrode 7 disposed on the outer circumference of the internal electrode 6. Since the outer diameter d1 of the internal electrode 6 is larger than the diameter d2 of the reduced diameter portion 3B, the flow of the active gas from the flow path 8 to the introduction path 3 is made smoother, and the flow velocity of the active gas blown out from the irradiation port 1c can be increased.

[0035] In the irradiation device 10 of this embodiment, the tip 6a of the internal electrode 6 and the base end 1e of the reduced diameter portion 3B of the introduction path 3 are spaced apart in the discharge direction. If the head portion 1b is made of metal, and the tip 6a of the internal electrode 6 and the base end 1e of the reduced-diameter portion 3B of the introduction path 3 are close together, then when a high voltage is applied to the internal electrode 6, dielectric breakdown may occur, causing a discharge between the head portion 1b and the internal electrode 6, and preventing the discharge from occurring at the intended location (discharge portion 2A). Therefore, by separating the tip 6a of the internal electrode 6 and the base end 1e of the reduced-diameter portion 3B of the introduction path 3, dielectric breakdown is made less likely to occur. Also, if the head portion 1b is made of a non-metallic material and the outer cylinder member 9 is made of metal, a discharge may occur between the internal electrode 6 and the outer cylinder member 9 in the same manner as described above.

[0036] According to the irradiation device 10 of this embodiment, the diameter of the introduction passage 3 is larger at the rear end than at the front end, which facilitates the flow of the active gas inside the introduction passage 3 and increases the flow velocity of the active gas blown out from the irradiation port 1c.

[0037] According to the irradiation device 10 of this embodiment, the diameter of the introduction passage 3 decreases in stages from the rear end to the front end, which facilitates the flow of the active gas inside the introduction passage 3 and increases the flow velocity of the active gas blown out from the irradiation port 1c.

[0038] According to the irradiation device 10 of this embodiment, the diameter of the introduction passage 3 decreases from the rear end to the front end, which facilitates the flow of the active gas inside the introduction passage 3 and increases the flow velocity of the active gas blown out from the irradiation port 1c.

[0039] <Other Embodiments> However, the present invention is not limited to the embodiments described above.

[0040] For example, a modified irradiation device 20 (20A to 20E) as shown in Figures 6 to 11 may be used. In the modified irradiation device 20 (20A to 20E), the same reference numerals are used for parts that are the same as those in the above embodiment, and their descriptions are omitted; only the differences will be described.

[0041] The modified irradiation device 20 shown in Figures 6 to 11 differs from the irradiation device 10 shown in Figure 1 in that it has an irradiation tube (nozzle) 21. The irradiation device 20 includes an outer cylindrical member 9 that covers the plasma generation unit 2, and an irradiation tube 21 that protrudes from the outer cylindrical member 9 and leads the active gas to the irradiation target. Furthermore, the head portion 1b has a fitting hole (female thread) 1d at its tip. The fitting hole 1d is a hole for receiving the irradiation tube 21. The irradiation tube 21 has a detachable mechanism that allows it to be attached to and detached from the outer cylinder member 9. The detachable mechanism allows the irradiation tube 21 to be attached to and detachably and replaceably from the outer cylinder member 9. Specifically, as a detachable mechanism, the irradiation tube 21 has a fitting projection (male thread) 21a that fits into the fitting hole 1d provided at the tip of the head portion 1b, as shown in Figures 6 to 11. In addition, the irradiation tube 21 may have a mechanism, not shown in the figures, that allows it to be attached to and detached by fitting it into the tip of the outer cylinder member 9 (the side opposite to the part to which the cable is connected). The diameter-reducing section 3B of the introduction passage 3 includes a first diameter-reducing section 3B1 provided inside the head section 1b, and a second diameter-reducing section 3B2 inside the irradiation tube 21 that protrudes from the outer cylindrical member 9 and leads the active gas to the irradiation target. In other words, the diameter-reducing section 3B of the introduction passage 3 is provided from the base end 1e on the flow path 8 side to the irradiation port 21b of the irradiation tube 21.

[0042] The irradiation tube 21 may be made of a metal such as stainless steel, or it may be made of the non-metallic material mentioned above. The materials of the irradiation tube 21 and the head portion 1b may be the same or different. In other words, the irradiation tube 21 and the head portion 1b may be made of metal, or they may be made of the non-metallic material mentioned above.

[0043] If the irradiation tube 21 and the head portion 1b are made of metal, at least a portion of the inner surface 3b of the first diameter-reducing portion 3B1 and the inner surface 3c of the second diameter-reducing portion 3B2 are made of the non-metallic material. That is, the irradiation device 20 has a layer (protective layer) made of a non-metallic material on at least a portion of the inner surface 3b of the first diameter-reducing portion 3B1 and the inner surface 3c of the second diameter-reducing portion 3B2.

[0044] According to the modified irradiation device 20, the device has an outer cylindrical member 9 that covers the plasma generating unit 2, and an irradiation tube 21 that protrudes from the outer cylindrical member 9 and leads the active gas to the irradiation target. The diameter-reducing section 3B has a first diameter-reducing section 3B1 provided inside the head section 1b and a second diameter-reducing section 3B2 inside the irradiation tube, which makes it easier to irradiate the irradiation target with the active gas.

[0045] In this modified version of the irradiation device 20, the irradiation tube 21 has a detachable mechanism that allows it to be attached to and detached from the outer cylinder member 9, so that the irradiation tube 21 that has been corroded by the plasma can be replaced with a new one. Furthermore, the irradiation tube 21 can be used as a disposable item. This helps to suppress the occurrence of infectious diseases via the irradiation tube 21.

[0046] In this modified example, the irradiation device 20 has an introduction path 3 with the structure shown in Figures 7 to 11. The modified irradiation device 20A(20) shown in Figure 7 differs from the irradiation device 10 shown in Figure 2 in that it has an irradiation tube 21. The diameter-reducing portion 3B includes a first diameter-reducing portion 3B1 provided inside the head portion 1b, and a second diameter-reducing portion 3B2 located inside the irradiation tube 21 that protrudes from the outer cylindrical member 9 and guides the active gas to the irradiation target. As shown in Figure 7, the diameter of the reduced diameter portion 3B is larger at the rear end than at the front end. In this modified example, the diameter d8 at the rear end of the reduced diameter portion 3B is larger than the diameter d9 at the front end (irradiation port 21b) of the reduced diameter portion 3B. In this modified example, at least a portion of the inner surface 3b of the first diameter-reducing portion 3B1 in the head portion 1b and the inner surface 3c of the second diameter-reducing portion 3B2 in the irradiation tube 21 are made of the non-metallic material and have non-conductive portions.

[0047] The modified irradiation device 20B(20) shown in Figure 8 differs from the irradiation device 10 shown in Figure 3 in that it has an irradiation tube 21. The diameter-reducing section 3B includes a first diameter-reducing section 3B1 provided inside the head section 1b, and a second diameter-reducing section 3B2 and a third diameter-reducing section 3B3 located inside the irradiation tube 21 that protrudes from the outer cylindrical member 9 and leads the active gas to the irradiation target. As shown in Figure 8, the diameter of the reduced diameter portion 3B decreases in stages from the rear end to the front end. In this modified example, the reduced diameter portion 3B has, in order from the rear end to the front end, a first reduced diameter portion 3B1, a second reduced diameter portion 3B2, and a third reduced diameter portion 3B3. That is, the diameter of the first reduced diameter portion 3B1 is larger than the diameter of the second reduced diameter portion 3B2, and the diameter of the second reduced diameter portion 3B2 is larger than the diameter of the third reduced diameter portion 3B3. In the modified example shown in Figure 8, the reduced diameter portion 3B is composed of three parts that decrease in stages from the rear end to the front end, but this modified example is not limited to this. In this modified example, the reduced diameter portion 3B may be composed of two or more parts that decrease in stages from the rear end to the front end. In this modified example, at least a portion of the inner surface 3b of the first diameter-reducing portion 3B1 in the head portion 1b, the inner surface 3c of the second diameter-reducing portion 3B2 in the irradiation tube 21, and the inner surface 3d of the third diameter-reducing portion 3B3 are made of the non-metallic material and have non-conductive portions.

[0048] The modified irradiation device 20C(20) shown in Figure 9 differs from the irradiation device 10 shown in Figure 4 in that it has an irradiation tube 21. The diameter-reducing portion 3B includes a first diameter-reducing portion 3B1 provided inside the head portion 1b, and a second diameter-reducing portion 3B2 located inside the irradiation tube 21 that protrudes from the outer cylindrical member 9 and guides the active gas to the irradiation target. As shown in Figure 9, the inner diameter of the reduced diameter section 3B decreases from the rear end to the front end. That is, the reduced diameter section 3B has a tapered shape. In the reduced diameter section 3B, the diameter d10 at the rear end of the first reduced diameter section 3B1 is larger than the diameter d11 at the front end (irradiation port 21b) of the second reduced diameter section 3B2. In this modified example, at least a portion of the inner surface 3b of the first diameter-reducing portion 3B1 in the head portion 1b and the inner surface 3c of the second diameter-reducing portion 3B2 in the irradiation tube 21 are made of the non-metallic material and have non-conductive portions.

[0049] The modified irradiation device 20D(20) shown in Figure 10 differs from the irradiation device 10 shown in Figure 5 in that it has an irradiation tube 21. The diameter-reducing portion 3B includes a first diameter-reducing portion 3B1 provided inside the head portion 1b, and a second diameter-reducing portion 3B2 located inside the irradiation tube 21 that protrudes from the outer cylindrical member 9 and guides the active gas to the irradiation target. As shown in Figure 10, the reduced diameter section 3B has a first reduced diameter section 3B1 which has a tapered shape that decreases in diameter from the rear end to the front end, and a second reduced diameter section 3B2 which is provided closer to the front end than the first reduced diameter section 3B1 and has a constant diameter along the direction of the pipe axis O1.

[0050] The modified irradiation device 20E(20) shown in Figure 11 has a bent irradiation tube 21. The bending of the irradiation tube 21 means that the irradiation port 21b moves away from the tube axis O1 as it approaches the tip of the irradiation tube 21. The inner diameter of the irradiation tube 21 may be larger at the rear end than at the front end. Alternatively, the inner diameter of the irradiation tube 21 may gradually decrease from the rear end towards the front end. Furthermore, the inner diameter of the irradiation tube 21 may decrease in diameter from the rear end towards the front end. In other words, the irradiation tube 21 may have a tapered shape. In this case, where the inner diameter of the irradiation tube 21 decreases from the rear end towards the front end, the inner diameter d12 of the irradiation port 21b is preferably 0.5 mm or more and 1.0 mm or less.

[0051] The irradiation device 20E(20) of this modified example provides the same effects as the irradiation device 20 of the first modified example described above. Furthermore, the irradiation device 20E(20) of this modified example has a bent irradiation tube 21, which makes it easier to irradiate the target with the active gas.

[0052] [Plasma irradiation device] A plasma irradiation device according to one embodiment of the present invention is a plasma jet irradiation device or an active gas irradiation device. A plasma jet irradiation device generates plasma. The plasma jet irradiation device directly irradiates the target object with the generated plasma and reactive species. The reactive species are generated by the reaction of the plasma with gas in the plasma or gas in the vicinity of the plasma. Examples of reactive species include reactive oxygen species and reactive nitrogen species. Examples of reactive oxygen species include hydroxyl radicals, singlet oxygen, ozone, hydrogen peroxide, and superoxide anion radicals. Examples of reactive nitrogen species include nitric oxide, nitrogen dioxide, peroxynitrite, nitrite peroxide, and dinitrogen trioxide.

[0053] The active gas irradiation device generates plasma. The active gas irradiation device irradiates the target object with an active gas containing active species. The active species are generated by the reaction of the plasma with gas in the plasma or gas in the vicinity of the plasma.

[0054] The following describes one embodiment of a plasma irradiation apparatus according to one embodiment of the present invention. The plasma irradiation apparatus in this embodiment is an active gas irradiation apparatus. Figure 12 is a schematic diagram showing the plasma irradiation apparatus of this embodiment. Figure 13 is a block diagram showing the schematic configuration of the plasma irradiation apparatus of this embodiment. As shown in Figures 12 and 13, the plasma irradiation apparatus 100 of this embodiment comprises an irradiation device 10, a supply unit 110, a gas pipeline 120, electrical wiring 130, a supply source 140, a notification unit 150, and a control unit 160 (calculation unit).

[0055] The supply unit 110 supplies power and plasma generating gas to the irradiation device 10. The supply unit 110 houses the supply source 140. The supply source 140 houses the plasma generating gas. The supply unit 110 is connected to a power source (not shown), such as a 100V household power supply. The gas pipeline 120 connects the irradiation device 10 and the supply unit 110. The electrical wiring 130 connects the irradiation device 10 and the supply unit 110. In this embodiment, the gas pipeline 120 and the electrical wiring 130 are independent of each other, but the gas pipeline 120 and the electrical wiring 130 may be integrated.

[0056] As shown in Figure 12, the supply unit 110 supplies electricity and plasma generating gas to the irradiation device 10. The supply unit 110 can adjust the voltage and frequency applied between the internal electrode 6 and the external electrode 7. The supply unit 110 includes a housing 111 that houses the supply source 140. The housing 111 detachably houses the supply source 140. This allows the supply source 140 to be replaced when the plasma generating gas inside the supply source 140 housed in the housing 111 runs out.

[0057] The supply source 140 supplies plasma generation gas to the plasma generation unit 2. The supply source 140 is a pressure-resistant vessel containing plasma generation gas. As shown in Figure 13, the supply source 140 is detachably attached to piping 145 located inside the housing 111. Piping 145 connects the supply source 140 to the gas pipeline 120. The piping 145 is fitted with a solenoid valve 141, a pressure regulator 143, a flow controller 144, and a pressure sensor 142 (remaining amount sensor).

[0058] When the solenoid valve 141 is open, plasma generating gas is supplied from the supply source 140 to the irradiation device 10 via the piping 145 and gas pipeline 120. In the illustrated example, the solenoid valve 141 is not configured to allow adjustment of the valve opening, but only to switch between open and closed positions. However, the solenoid valve 141 may be configured to allow adjustment of the valve opening. The pressure regulator 143 is located between the solenoid valve 141 and the supply source 140. The pressure regulator 143 reduces the pressure of the plasma generating gas flowing from the supply source 140 to the solenoid valve 141 (depressurizes the plasma generating gas).

[0059] The flow controller 144 is located between the solenoid valve 141 and the gas pipeline 120. The flow controller 144 adjusts the flow rate (amount supplied per unit time) of the plasma generation gas that has passed through the solenoid valve 141. The flow controller 144 adjusts the flow rate of the plasma generation gas to, for example, 3 L / min. The pressure sensor 142 detects the remaining amount V1 of plasma generation gas in the supply source 140. The pressure sensor 142 measures the pressure (residual pressure) inside the supply source 140 as the remaining amount V1. The pressure sensor 142 measures the pressure of the plasma generation gas passing between the pressure regulator 143 and the supply source 140 (primary side of the pressure regulator 143) as the pressure of the supply source 140. For example, the AP-V80 series from Keyence Corporation (specifically, for example, AP-15S) can be used as the pressure sensor 142.

[0060] A fitting 146 is provided at the end of the piping 145 on the supply source 140 side. The supply source 140 is detachably attached to the fitting 146. By attaching and detaching the supply source 140 to the fitting 146, the supply source 140 can be replaced while the solenoid valve 141, pressure regulator 143, flow controller 144, and pressure sensor 142 (hereinafter referred to as "solenoid valve 141, etc.") remain fixed to the housing 111. In this case, a common solenoid valve 141, etc., can be used for both the supply source 140 before replacement and the supply source 140 after replacement.

[0061] As shown in Figure 12, the gas pipeline 120 is a path for supplying plasma generation gas from the supply unit 110 to the irradiation device 10. The gas pipeline 120 is connected to the rear end of the tubular dielectric 5 of the irradiation device 10. There are no particular restrictions on the material of the gas pipeline 120, and materials known to be used for gas pipes can be applied. Examples of materials for the gas pipeline 120 include resin pipes and rubber tubes, and flexible materials are preferred.

[0062] The electrical wiring 130 supplies electricity from the supply unit 110 to the irradiation device 10. The electrical wiring 130 is connected to the internal electrode 6, external electrode 7, and operating switch 4 of the irradiation device 10. There are no particular restrictions on the material of the electrical wiring 130, and any known material used for electrical wiring can be used. Examples of materials for the electrical wiring 130 include metal conductors covered with insulating material.

[0063] The control unit 160, as shown in Figure 13, is configured using an information processing device. Specifically, the control unit 160 includes a CPU (Central Processor Unit), memory, and auxiliary storage device connected by a bus. The control unit 160 operates by executing a program. The control unit 160 may be built into, for example, the supply unit 110. The control unit 160 controls the irradiation device 10, the supply unit 110, and the notification unit 150.

[0064] The control unit 160 is electrically connected to the operation switch 4 of the irradiation device 10. When the operation switch 4 is operated, an electrical signal is sent from the operation switch 4 to the control unit 160. When the control unit 160 receives the electrical signal, it activates the solenoid valve 141 and the flow controller 144, and applies a voltage between the internal electrode 6 and the external electrode 7.

[0065] In this embodiment, the operation switch 4 is a push button, and when the user presses the operation switch 4 once (the user operates the operation switch 4), the control unit 160 receives the electrical signal. The control unit 160 then opens the solenoid valve 141 for a predetermined time, causing the flow rate controller 144 to adjust the flow rate of the plasma generating gas that has passed through the solenoid valve 141, and applies a voltage between the internal electrode 6 and the external electrode 7 for a predetermined time. As a result, a certain amount of plasma generating gas is supplied from the supply source 140 to the plasma generating unit 2, and the active gas is continuously discharged from the irradiation port of the irradiation device 10 for a certain period of time (for example, several seconds to several tens of seconds, 30 seconds in this embodiment). Note that the operation switch 4 is not limited to being provided on the outer cylinder member 9, but may also be in the form of a foot switch that is independent of the irradiation device 10 and connected to the control unit 160.

[0066] The control unit 160 calculates the remaining number of times N for plasma generation gas. The remaining number N is the number of times plasma generation gas can be supplied from the supply source 140 to the plasma generation unit 2 using the plasma generation gas remaining in the supply source 140. The remaining number N can be calculated from the remaining amount V1 of plasma generation gas in the supply source 140. The remaining number N can be calculated (N = V1 / V2) based on the remaining amount V1 and the amount of plasma generation gas supplied per operation of the operation switch 4, V2.

[0067] The notification unit 150 notifies the remaining number of plays N. The notification unit 150 displays the remaining number of plays N calculated by the control unit 160 as a number. The notification unit 150 may be, for example, a display device capable of displaying any number, or a mechanical counter. The notification unit 150 may also notify the remaining number of plays N by voice. In this case, the notification unit 150 may be, for example, a speaker.

[0068] Next, the method of using the plasma irradiation device 100 will be explained. For example, a user such as a doctor moves the irradiation device 10 and points the tip of the irradiation device 10 towards the target to be irradiated. At this time, the user grasps the irradiation device 10 with their dominant hand (the hand that operates the irradiation device 10). In this state, the user presses the operation switch 4 to supply electricity and plasma generating gas from the supply source 140 to the irradiation device 10. The plasma generating gas supplied to the irradiation device 10 flows into the interior of the tubular dielectric 5 from the rear end of the tubular dielectric 5. The plasma generating gas is ionized at the position where the internal electrode 6 and the external electrode 7 face each other, and becomes plasma.

[0069] In this embodiment, the internal electrode 6 and the external electrode 7 face each other in directions perpendicular to the direction of flow of the plasma generating gas. The plasma generated at the position where the outer surface of the internal electrode 6 and the inner surface of the external electrode 7 face each other flows through the flow path 8 and the introduction path 3 in that order. During this time, the plasma flows while changing its gas composition and becomes an active gas containing active species such as radicals.

[0070] The generated activated gas is discharged from the irradiation port 1c. The discharged activated gas further activates a portion of the gas near the irradiation port 1c, generating activated species. The activated gas containing these activated species is then irradiated onto the target object.

[0071] Examples of materials that can be irradiated include cells, biological tissues, individual organisms, organic materials (e.g., resins), and inorganic materials (e.g., ceramics, metals). Examples of biological tissues include the various organs of the internal system, epithelial tissues covering the body surface and the inner surfaces of body cavities, periodontal tissues such as gums, alveolar bone, periodontal ligament and cementum, teeth, and bone. The biological individual can be any of the following: humans, dogs, cats, pigs, or other mammals; birds; fish, etc.

[0072] Examples of plasma generation gases include noble gases such as helium, neon, argon, and krypton, as well as nitrogen, oxygen, and air. These gases may be used individually or in combination of two or more. The plasma generation gas is preferably composed mainly of nitrogen. Here, "primarily composed of nitrogen" means that the nitrogen content in the plasma generation gas is more than 50% by volume. In other words, the nitrogen content in the plasma generation gas is preferably more than 50% by volume, more preferably 70% by volume or more, even more preferably 80% to 100% by mass, and particularly preferably 90% to 100% by mass. There are no particular restrictions on gas components other than nitrogen in the plasma generation gas; for example, oxygen, noble gases, etc., can be cited.

[0073] If the plasma irradiation device 100 is an intraoral treatment instrument, the oxygen concentration of the plasma generating gas introduced into the tubular dielectric 5 is preferably 1 volume percent or less. If the oxygen concentration is below the upper limit, ozone generation can be reduced.

[0074] The flow rate of the plasma generation gas introduced into the tubular dielectric 5 is preferably 1 L / min to 10 L / min. If the flow rate of the plasma generating gas introduced into the tubular dielectric 5 is above the lower limit, it is easier to suppress the temperature rise of the irradiated surface (the surface of the irradiated object that is irradiated with the active gas) of the irradiated object. If the flow rate of the plasma generating gas is below the upper limit, the cleaning, activation, or healing of the irradiated object can be further promoted.

[0075] The AC voltage applied between the internal electrode 6 and the external electrode 7 is preferably 3kVpp to 20kVpp. Here, the unit "Vpp (Volt peak to peak)" representing the AC voltage is the potential difference between the highest and lowest values ​​of the AC voltage waveform. Furthermore, if the internal electrode 6 is a cylindrical member without irregularities on its outer surface, the AC voltage applied between the internal electrode 6 and the external electrode 7 is preferably 6kVpp or higher. When using an internal electrode 6 without irregularities on its outer surface, it is necessary to increase the AC voltage applied between the internal electrode 6 and the external electrode 7 compared to when using an internal electrode 6 with irregularities on its outer surface. If the applied AC voltage is below the upper limit, the temperature of the generated plasma can be kept low. If the applied AC voltage is above the lower limit, plasma can be generated even more efficiently.

[0076] The frequency of the alternating current applied between the internal electrode 6 and the external electrode 7 is preferably 0.5 kHz or more and less than 40 kHz, more preferably 10 kHz or more and less than 30 kHz, even more preferably 15 kHz or more and less than 25 kHz, and particularly preferably 18 kHz or more and less than 22 kHz. If the frequency of the AC current is below the aforementioned upper limit, the temperature of the generated plasma can be kept low. If the frequency of the AC current is above the aforementioned lower limit, plasma can be generated even more efficiently.

[0077] The temperature of the active gas irradiated from the irradiation port 1c of the irradiation device 10 is preferably 50°C or lower, more preferably 45°C or lower, and even more preferably 40°C or lower. If the temperature of the active gas irradiated from the irradiation port 1c is below the aforementioned upper limit, it is easier to lower the temperature of the irradiated surface to 40°C or below. By lowering the temperature of the irradiated surface to 40°C or below, irritation to the affected area can be reduced, even if the irradiated area is a diseased area. There is no particular lower limit to the temperature of the active gas irradiated from the irradiation port 1c; for example, it is 10°C or higher. The temperature of the active gas is the value measured using a thermocouple at irradiation port 1c.

[0078] The distance from the irradiation port 1c to the irradiated surface (irradiation distance) is preferably, for example, 0.01 mm to 10 mm. If the irradiation distance is greater than or equal to the lower limit, the temperature of the irradiated surface can be lowered, further reducing irritation to the irradiated surface. If the irradiation distance is less than or equal to the upper limit, the healing effect can be further enhanced.

[0079] The temperature of the irradiated surface at a distance of 1 mm to 10 mm from the irradiation port 1c is preferably 40°C or lower. A temperature of 40°C or lower reduces irritation to the irradiated surface. There is no particular lower limit to the temperature of the irradiated surface, but for example, it should be 10°C or higher. The temperature of the irradiated surface can be adjusted by a combination of factors such as the AC voltage applied between the internal electrode 6 and the external electrode 7, the discharge rate of the irradiated active gas, and the length from the tip of the internal electrode 6 to the irradiation port 1c. The temperature of the irradiated surface can be measured using a thermocouple.

[0080] Examples of active species (radicals, etc.) contained in the active gas include hydroxyl radicals, singlet oxygen, ozone, hydrogen peroxide, superoxide anion radicals, nitric oxide, nitrogen dioxide, peroxynitrite, nitrite peroxide, and dinitrogen trioxide. The types of active species contained in the active gas can be further adjusted, for example, to suit the type of gas used for plasma generation.

[0081] The density of hydroxyl radicals in the active gas (radical density) is preferably 0.1 μmol / L to 300 μmol / L, more preferably 0.1 μmol / L to 100 μmol / L, and even more preferably 0.1 μmol / L to 50 μmol / L. When the radical density is above the lower limit, it is easier to promote the purification, activation, or healing of abnormalities of the irradiation target selected from cells, biological tissues, and individual organisms. When the radical density is below the upper limit, irritation to the irradiated surface can be reduced.

[0082] Radical density can be measured, for example, by the following method: A 0.2 mL solution of DMPO (5,5-dimethyl-1-pyrroline-N-oxide) 0.2 mol / L is irradiated with an active gas for 30 seconds. The distance from the irradiation port 1c to the liquid surface is set to 5.0 mm. The hydroxyl radical concentration of the irradiated solution is measured using electron spin resonance (ESR) spectroscopy and defined as the radical density.

[0083] The density of singlet oxygen in the active gas (singlet oxygen density) is preferably 0.1 μmol / L to 300 μmol / L, more preferably 0.1 μmol / L to 100 μmol / L, and even more preferably 0.1 μmol / L to 50 μmol / L. When the singlet oxygen density is above the lower limit, it is easier to promote the purification, activation, or healing of abnormalities of the irradiated target, such as cells, biological tissues, and individual organisms. When it is below the upper limit, irritation to the irradiated surface can be reduced.

[0084] Singlet oxygen density can be measured, for example, by the following method: A 0.4 mL solution of 0.1 mol / L TPC (2,2,5,5-tetramethyl-3-pyrroline-3-carboxamide) is irradiated with an active gas for 30 seconds. The distance from the irradiation port 1c to the liquid surface is set to 5.0 mm. The singlet oxygen concentration of the irradiated solution is measured using electron spin resonance (ESR) and defined as the singlet oxygen density.

[0085] The flow rate of the activated gas irradiated from the irradiation port 1c is preferably 1 L / min to 10 L / min. If the flow rate of the active gas irradiated from the irradiation port 1c is above the lower limit, the effect of the active gas on the irradiated surface can be sufficiently enhanced. If the flow rate of the active gas irradiated from the irradiation port 1c is below the upper limit, it is possible to prevent the temperature of the irradiated surface from rising excessively. In addition, if the irradiated surface is wet, it is possible to prevent rapid drying of the irradiated surface. Furthermore, if the irradiated surface is a diseased area, it is possible to suppress irritation to the patient. In the plasma irradiation device 100, the flow rate of the active gas irradiated from the irradiation port 1c can be adjusted by the amount of plasma generation gas supplied to the tubular dielectric 5.

[0086] The activated gas generated by the plasma irradiation device 100 has the effect of promoting the healing of injuries and abnormalities. By irradiating cells, living tissues, or living organisms with the activated gas, the irradiated area can be cleansed, activated, or its healing can be promoted.

[0087] When irradiating an area with an active gas to promote the healing of injuries or abnormalities, there are no particular restrictions on the frequency, number of irradiations, or duration of irradiation. For example, when irradiating the affected area with an active gas at a dose of 1 L / min to 5.0 L / min, irradiation conditions such as 1 to 5 times a day, each time for 10 seconds to 10 minutes, for 1 to 30 days are preferable from the viewpoint of promoting healing.

[0088] The plasma irradiation device 100 of this embodiment is particularly useful as an intraoral treatment instrument and a dental treatment instrument. Furthermore, the plasma irradiation device 100 of this embodiment is also suitable as an animal treatment instrument (for example, a treatment device for treating the oral cavity of animals other than humans).

[0089] According to the plasma irradiation apparatus 100 of this embodiment, since it is equipped with an irradiation device 10, it is possible to irradiate the target object with an active gas that has a high density of active species. [Examples]

[0090] [Example 1] As shown in Figure 7, an irradiation device equipped with an irradiation tube at its tip was used, and an active gas was blown out from the irradiation port of the irradiation device. The irradiation tube used had an inner diameter of 1 mm for the inlet and an inner diameter of 0.8 mm for the irradiation port, and was entirely made of polypropylene. The irradiation tube had a reduced diameter section, and the entire reduced diameter section was a non-conductive part made of polypropylene. The density of hydroxyl radicals (reactive species) contained in the activated gas ejected from the irradiation port was measured using the method described above. The results are shown in Figure 14. The density of singlet oxygen (reactive species) contained in the activated gas ejected from the irradiation port was measured using the method described above. The results are shown in Figure 15.

[0091] [Comparative Example 1] An irradiation device equipped with an irradiation tube at its tip, as shown in Figure 6, was used, and an active gas was blown out from the irradiation port of the irradiation device. The irradiation tube used had an inner diameter of 1 mm for both the inlet and the irradiation port, and was entirely made of polypropylene. The irradiation tube did not have a reduced diameter section. In the same manner as in Example 1, the density of hydroxyl radicals (reactive species) and singlet oxygen (reactive species) contained in the activated gas blown out from the irradiation port was measured. The results are shown in Figures 14 and 15.

[0092] [Comparative Example 2] The irradiation tube used was the same as in Comparative Example 1, except that it had an inner diameter of 1 mm at the irradiation port and was made entirely of stainless steel. The activated gas was blown out from the irradiation port of the irradiation device. The irradiation tube did not have any non-conductive parts. In the same manner as in Example 1, the density of hydroxyl radicals (reactive species) and singlet oxygen (reactive species) contained in the activated gas blown out from the irradiation port was measured. The results are shown in Figures 14 and 15.

[0093] [Comparative Example 3] The irradiation tube used was the same as in Example 1, except that it had an inner diameter of 0.8 mm at the irradiation port and was made entirely of stainless steel. The activated gas was blown out from the irradiation port of the irradiation device. The irradiation tube did not have any non-conductive parts. In the same manner as in Example 1, the density of hydroxyl radicals (reactive species) and singlet oxygen (reactive species) contained in the activated gas blown out from the irradiation port was measured. The results are shown in Figures 14 and 15.

[0094] From the results in Figures 14 and 15, it was confirmed that in Example 1, which used an irradiation tube with an inlet diameter of 1 mm, an irradiation port diameter of 0.8 mm, and made entirely of polypropylene, the density of hydroxyl radicals and singlet oxygen contained in the activated gas blown out from the irradiation port was higher than in Comparative Examples 2 and 3, which used an irradiation tube made entirely of stainless steel. Furthermore, comparing Example 1 with Comparative Example 1, it was confirmed that Example 1, which has a smaller inner diameter of the irradiation port, had a higher density of hydroxyl radicals and singlet oxygen contained in the activated gas blown out from the irradiation port than Comparative Example 1.

[0095] [Example 2] An irradiation device equipped with an irradiation tube at its tip, as shown in Figure 6, was used, and an active gas was blown out from the irradiation port of the irradiation device. The irradiation tube used was a straight tube made entirely of polypropylene, with an inlet length of 51 mm, an inner diameter of 2.0 mm at the rear end of the inlet, and an inner diameter of 0.8 mm at the irradiation port. The irradiation tube had a reduced diameter section, and the entire reduced diameter section was a non-conductive part made of polypropylene. The density of singlet oxygen (reactive species) contained in the activated gas ejected from the irradiation port was measured using the method described above. The results are shown in Figure 16.

[0096] [Example 3] An irradiation device equipped with an irradiation tube at its tip, as shown in Figure 11, was used, and an active gas was blown out from the irradiation port of the irradiation device. The irradiation tube used had an inlet length of 51 mm, an inner diameter of 2.0 mm at the rear end of the inlet, and an inner diameter of 0.8 mm at the irradiation port, and was bent and made entirely of polypropylene. The irradiation tube had a reduced diameter section, and the entire reduced diameter section was a non-conductive part made of polypropylene. The density of singlet oxygen (reactive species) contained in the activated gas ejected from the irradiation port was measured using the method described above. The results are shown in Figure 16.

[0097] [Comparative Example 4] An irradiation device equipped with an irradiation tube at its tip, as shown in Figure 6, was used, and an active gas was blown out from the irradiation port of the irradiation device. The irradiation tube used was a straight tube made entirely of stainless steel, with an inlet length of 28.4 mm, an inner diameter of 1.0 mm at the rear end of the inlet, and an inner diameter of 1.0 mm at the irradiation port. The irradiation tube did not have any non-conductive parts. The density of singlet oxygen (reactive species) contained in the activated gas ejected from the irradiation port was measured using the method described above. The results are shown in Figure 16.

[0098] [Comparative Example 5] An irradiation device equipped with an irradiation tube at its tip, as shown in Figure 11, was used, and an active gas was blown out from the irradiation port of the irradiation device. The irradiation tube used was a bent tube made entirely of stainless steel, with an inlet length of 28.4 mm, an inner diameter of 1.0 mm at the rear end of the inlet, and an inner diameter of 1.0 mm at the irradiation port. The irradiation tube did not have any non-conductive parts. The density of singlet oxygen (reactive species) contained in the activated gas ejected from the irradiation port was measured using the method described above. The results are shown in Figure 16.

[0099] As shown in Figure 16, in Example 2, which used a bent irradiation tube with an introduction path length of 51 mm, an inner diameter of 2.0 mm at the rear end of the introduction path, and an inner diameter of 0.8 mm at the irradiation port, and was entirely made of polypropylene, it was confirmed that the density of hydroxyl radicals and singlet oxygen contained in the activated gas blown out from the irradiation port was higher than in Comparative Example 4, which used a straight tubular irradiation tube with an introduction path length of 28.4 mm, an inner diameter of 1.0 mm at the rear end of the introduction path, and an inner diameter of 1.0 mm at the irradiation port, and was entirely made of stainless steel. [Industrial applicability]

[0100] The irradiation device and plasma irradiation apparatus equipped with the present invention are useful for applications such as oral cavity treatment, dental treatment, and animal treatment. Examples of diseases and symptoms that can be treated by irradiation with active gas include oral diseases such as gingivitis and periodontal disease, and skin wounds. [Explanation of symbols]

[0101] 1 Cowling 1a Torso 1b Head section 1c irradiation port 2 Plasma generation unit 3 Introductory route 4. Operation switches 5. Tubular Dielectrics 6 Internal electrode 7 External electrode 8 channels 9 Outer cylinder member 10,20 Irradiation devices 21 Irradiation tube 100 Plasma Irradiation Device 110 supply units 120 Gas pipeline 130 Electrical Wiring 140 Source 150 Hochi Department 160 Control Unit

Claims

1. An electrode that generates plasma when voltage is applied, An introduction path is provided that communicates with the irradiation port for irradiating the target with an active gas, and extends from the tip of the electrode on the irradiation port side to the irradiation port, The irradiation tube having the aforementioned irradiation port comprises, The introduction path has a reduced diameter section in which the diameter decreases in the direction of discharge for guiding the active gas to the irradiation target, The inner surface of the reduced diameter portion has a non-conductive portion made of a non-metallic material, The diameter of the rear end of the reduced diameter portion is greater than the diameter of the front end of the reduced diameter portion, and the ratio of the rear end diameter to the front end diameter (rear end diameter / front end diameter) is greater than 1 and less than or equal to 100. The diameter-reduced portion is formed in the flow path inside the irradiation tube. The irradiation device has a detachable mechanism for the irradiation tube.

2. The electrical resistivity of the nonmetallic material is 10 ６ Ωm or more 10 ２５ The irradiation device according to claim 1, wherein the ohm is Ωm or less.

3. The irradiation device according to claim 1 or 2, wherein at least the inner surface of the reduced diameter portion is made of a non-metallic material.

4. The system comprises an outer cylindrical member covering the plasma generation section including the electrodes, and an irradiation tube protruding from the outer cylindrical member for guiding the active gas to the irradiation target, The irradiation device according to any one of claims 1 to 3, wherein the introduction path includes a flow path inside the irradiation tube.

5. The irradiation device according to claim 4, wherein the irradiation tube is bent.

6. The irradiation device according to claim 4 or 5, wherein the irradiation tube has a detachable attachment mechanism, and the attachment mechanism is detachable from the outer cylindrical member.

7. The plasma generating unit comprises a tubular dielectric, an internal electrode disposed within the tubular dielectric and having a surface exposed to a plasma generating gas, and an external electrode disposed on the outer circumference of the internal electrode. The irradiation device according to any one of claims 4 to 6, wherein the outer diameter of the internal electrode is larger than the inner diameter of the reduced diameter portion.

8. The irradiation device according to any one of claims 1 to 7, wherein the inner diameter of the introduction passage is larger at the rear end than at the front end.

9. The irradiation device according to any one of claims 1 to 7, wherein the inner diameter of the introduction passage decreases in stages from the rear end to the front end.

10. The irradiation device according to any one of claims 1 to 7, wherein the inner diameter of the introduction passage decreases from the rear end to the front end.

11. A plasma irradiation apparatus comprising the irradiation device described in any one of claims 1 to 10.

12. An electrode that generates plasma when voltage is applied, An introduction path is provided that communicates with the irradiation port for irradiating the target with an active gas, and extends from the tip of the electrode on the irradiation port side to the irradiation port, The irradiation tube having the aforementioned irradiation port comprises, The introduction path has a reduced diameter section in which the diameter decreases in the direction of discharge for guiding the active gas to the irradiation target, The inner surface of the reduced diameter portion has a non-conductive portion made of a non-metallic material, The diameter of the rear end of the reduced diameter portion is greater than the diameter of the front end of the reduced diameter portion, and the ratio of the rear end diameter to the front end diameter (rear end diameter / front end diameter) is greater than 1 and less than or equal to 100. The diameter-reduced portion is formed in the flow path inside the irradiation tube. The aforementioned irradiation tube is an irradiation tube used in an irradiation device, having a detachable attachment / detachment mechanism.

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