Sterilization device, sterilization method, active oxygen supply device, and treatment device using active oxygen

Abstract

To provide a sterilization device, etc. exhibiting an excellent sterilization performance exceeding a sterilization performance by ozone or ultraviolet light .SOLUTION: A sterilization device includes: a plasma generator and an ultraviolet light source. The plasma generator is a plasma actuator provided with a first electrode and a second electrode, interposing a dielectric body, and configured to apply voltage between the two electrodes to cause an induced flow including ozone. The ultraviolet light source is arranged so that a surface of a to-be-processed product being a sterilization target can be irradiated. The plasma actuator is arranged so that the induced flow is supplied to the surface.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a sterilization device and a sterilization method. The present disclosure also relates to an active oxygen supply device. Furthermore, the present disclosure also relates to a treatment device using active oxygen. [Background technology]

[0002] Ultraviolet light and ozone are known as means for sterilizing objects, etc. Patent Document 1 addresses the problem that sterilization by ultraviolet light is limited to the part of the object to be sterilized that is irradiated with ultraviolet light, by using a sterilization device having an ozone supply device, an ultraviolet light generating lamp, and an agitator, and by irradiating ozone with ultraviolet light generated from the ultraviolet light generating lamp, the active oxygen generated is agitated, thereby sterilizing the shadow part of the sample as well. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 1-25865 Summary of the Invention [Problem to be solved by the invention]

[0004] The inventors of the present invention have investigated the sterilization performance of the sterilization method disclosed in Patent Document 1 and found that in some cases the sterilization performance was comparable to that of a conventional sterilization method using only ozone. The sterilization ability of active oxygen is said to far exceed that of ozone, so these results were unexpected. One aspect of the present disclosure is directed to providing a sterilization device and a sterilization method that exhibit superior sterilization performance that exceeds that of ozone or ultraviolet light. Another aspect of the present disclosure is directed to an active oxygen supply device that can actively supply active oxygen to a workpiece. Still another aspect of the present disclosure is directed to an active oxygen treatment device that can more efficiently treat the surface of a workpiece with active oxygen. [Means for solving the problem]

[0005] According to at least one aspect of the present disclosure, a housing having at least one opening; Located inside the housing Plasma generator and 、 Located inside the housing UV light source and 、 A sterilization device comprising: The plasma generating device comprises: a dielectric; a first electrode provided on a first surface of the dielectric; The dielectric is provided on a second surface opposite to the first surface, and the first electrode is With a dielectric between them They are arranged diagonally opposite each other Second electrode and, A plasma actuator having , The plasma actuator is the first electrode and the second electrode By applying a voltage between from the edge of the first electrode along an exposed portion of the first surface of the dielectric that is not covered with the first electrode; Generates an induced flow containing ozone thing and 、 The plasma actuator is The air flows out of the housing through the opening. , of the object to be sterilized Arranged to be supplied to the surface Crate , the ultraviolet light source is disposed so as to be able to irradiate the surface, and irradiates the induced flow with ultraviolet light to generate active oxygen in the induced flow; A disinfection device is provided.

[0006] Also, according to at least one aspect of the present disclosure, A sterilization method using the sterilization device of the present disclosure, The aforementioned A first electrode and The aforementioned Second electrode with supplying an ozone-containing induced flow generated by applying a voltage between the electrodes to the surface of the object to be sterilized; and, The ozone-containing induced flow is supplied to the surface of the object to be treated. , from the ultraviolet light source A sterilization method is provided, comprising the step of irradiating with ultraviolet light.

[0007] Further, according to at least one aspect of the present disclosure, a housing having at least one opening; Located inside the housing Plasma generator and 、 Located inside the housing UV light source and 、 Equipped with An active oxygen supplying device , The plasma generating device comprises: a dielectric; a first electrode provided on a first surface of the dielectric; The dielectric is provided on a second surface opposite to the first surface, and the first electrode is With a dielectric between them They are arranged diagonally opposite each other A second electrode and 、 Equipped with It is a plasma actuator that , The plasma actuator comprises: By applying a voltage between the first electrode and the second electrode and extending from the edge of the first electrode along the exposed portion of the first surface of the dielectric that is not covered with the first electrode. That 、 Generates an induced flow containing ozone thing and The plasma actuator is flows out of the housing through the opening, It is arranged to be supplied to the surface of the workpiece, The ultraviolet light source irradiates the induced flow with ultraviolet light to generate active oxygen in the induced flow. It is something , an active oxygen supply device is provided.

[0008] Furthermore, according to at least one aspect of the present disclosure, a housing having at least one opening; Located inside the housing Plasma generator and 、 Located inside the housing UV light source and 、 Equipped with A treatment device using active oxygen , The plasma generating device comprises: a dielectric; a first electrode provided on a first surface of the dielectric; The dielectric is provided on a second surface opposite to the first surface, and the first electrode is With a dielectric between them They are arranged diagonally opposite each other A second electrode and 、 Equipped with It is a plasma actuator that , The plasma actuator comprises: By applying a voltage between the first electrode and the second electrode and extending from the edge of the first electrode along the exposed portion of the first surface of the dielectric that is not covered with the first electrode. That 、 Generates an induced flow containing ozone thing and The plasma actuator is flows out of the housing through the opening, It is arranged to be supplied to the surface of the workpiece, The ultraviolet light source irradiates the induced flow with ultraviolet light to generate active oxygen in the induced flow. It is something , an active oxygen treatment device is provided. [Effects of the Invention]

[0009] According to one aspect of the present disclosure, a sterilization device that exhibits superior sterilization performance that exceeds that of sterilization methods using ozone or ultraviolet light can be obtained. Also, according to another aspect of the present disclosure, a sterilization method that exhibits superior sterilization performance that exceeds that of sterilization methods using ozone or ultraviolet light can be obtained. Furthermore, according to one aspect of the present disclosure, it is possible to obtain an active oxygen supplying device that can more actively supply active oxygen to an object to be treated. Furthermore, according to another aspect of the present disclosure, it is possible to obtain a treatment device using active oxygen that can more efficiently treat the surface of an object to be treated with active oxygen. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram showing the configuration of a sterilization apparatus according to one embodiment of the present disclosure. [Figure 2] FIG. 1 is a schematic diagram showing an example of the configuration of a plasma generating device. [Figure 3] FIG. 4 is an explanatory diagram of overlapping between a first electrode and a second electrode. [Figure 4] FIG. 4(a) is a schematic cross-sectional view of the sterilization apparatus according to this embodiment, and FIG. 4(b) is a plan view of the same. [Figure 5] FIG. 10 is a schematic cross-sectional view of a sterilization apparatus according to Comparative Example 4. [Figure 6]1 is a schematic diagram showing the configuration of an active oxygen supplying device according to one embodiment of the present disclosure, and is a plan view seen from the side having an opening in the housing. FIG. [Figure 7] 7 is a cross-sectional view taken along line AA of the active oxygen supplying device of FIG. 6. FIG. [Figure 8] FIG. 7 is an explanatory diagram of the active oxygen supplying device according to FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, specific examples of embodiments for carrying out this disclosure will be described with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of the components described in this embodiment may be changed as appropriate depending on the configuration of the components to which the disclosure is applied and various conditions. In other words, it is not intended to limit the scope of this disclosure to the following embodiments. In the present disclosure, unless otherwise specified, the expressions "XX to YY" or "XX to YY" representing a numerical range mean a numerical range including the lower and upper limits, which are the endpoints. When a numerical range is described in stages, the upper and lower limits of each numerical range can be combined in any way.

[0012] Furthermore, the term "bacteria" in the term "sterilization" according to the present disclosure refers to microorganisms, and examples of such microorganisms include fungi, bacteria, unicellular algae, viruses, protozoa, and the like, as well as animal or plant cells (including stem cells, dedifferentiated cells, and differentiated cells), tissue cultures, fused cells (including hybridomas) obtained by genetic engineering, dedifferentiated cells, and transformants (microorganisms). Examples of viruses include norovirus, rotavirus, influenza virus, adenovirus, coronavirus, measles virus, rubella virus, hepatitis virus, herpes virus, and HIV virus. Examples of bacteria include Staphylococcus aureus, Escherichia coli, Salmonella, Pseudomonas aeruginosa, Vibrio cholerae, Shigella, Bacillus anthracis, Mycobacterium tuberculosis, Clostridium botulinum, Clostridium tetani, and Streptococcus. Examples of fungi include Trichophyton, Aspergillus, and Candida.

[0013] Furthermore, in the following description, components having the same functions are given the same reference numerals in the drawings, and the description thereof may be omitted. Furthermore, in this specification, the active oxygen supplying device of the present disclosure and the treatment device using active oxygen of the present disclosure are also collectively referred to simply as "active oxygen supplying device."

[0014] According to the study by the present inventors, the reason why the sterilization ability of the sterilizer according to Patent Document 1 is limited is presumed to be as follows. In Patent Document 1, ozone is excited by irradiating it with ultraviolet light, generating active oxygen with extremely high disinfecting power. Here, the active oxygen is the superoxide anion radical (·O2 - ), hydroxyl radical (·OH), and other highly reactive oxygen species, which can instantly oxidize and decompose bacteria and viruses due to their own high reactivity.

[0015] However, because ozone absorbs ultraviolet rays extremely well, it is believed that the generation of active oxygen is limited to the vicinity of the ultraviolet emitting lamp in the sterilization device of Patent Document 1. In other words, it is believed that ultraviolet rays do not sufficiently reach ozone present at a distance from the ultraviolet emitting lamp, and active oxygen is unlikely to be generated at a distance from the ultraviolet emitting lamp. In addition, reactive oxygen species are very unstable and - The half-life of -6 seconds, and the half-life of OH is 10 -9 The active oxygen generated near the ultraviolet lamp is rapidly converted into stable oxygen and water in an extremely short time of only seconds. Therefore, it is difficult to fill the inside of the sterilizer body with the active oxygen generated near the ultraviolet lamp, and it is considered difficult to achieve significant sterilization with the active oxygen unless the object to be sterilized is placed very close to the ultraviolet lamp, for example, within about 1 cm from the ultraviolet lamp. In other words, when the object to be sterilized is located more than 1 cm away from the ultraviolet lamp, it is considered that the sterilization of the object to be sterilized is essentially performed by ozone. Therefore, it is considered that the sterilization performance of the sterilization method according to Patent Document 1 is comparable to that of conventional sterilization methods using only ozone. From these considerations, the present inventors have recognized that when treating an object to be treated using active oxygen, which has a short lifespan, it is necessary to more actively place the object or the surface to be treated in an active oxygen atmosphere. Based on this recognition, the present inventors conducted research and found that the sterilization apparatus and active oxygen supply apparatus of the embodiments described below can more actively place the object to be treated in an active oxygen atmosphere. In this disclosure, "treatment" of an object to be treated with active oxygen includes all treatments that can be achieved with active oxygen, such as surface modification (hydrophilization treatment) of the surface to be treated with active oxygen, sterilization, deodorization, and bleaching.

[0016] 1 shows a sterilization apparatus 101 according to one embodiment of the present disclosure. The sterilization apparatus 101 includes an ultraviolet light source 102 and a plasma generator 103 inside a sterilization container 112. The ultraviolet light source 102 is disposed so as to be able to irradiate a processing surface 105-1 of a processing target 105, which is a target for sterilization, placed on a placement table 110. In Fig. 1, reference numeral 109 denotes an induced flow.

[0017] 2 shows a cross-sectional structure of one embodiment of the plasma generator 103. The plasma generator is a so-called dielectric barrier discharge (DBD) plasma actuator (hereinafter sometimes simply referred to as "DBD-PA") in which a first electrode 203 is provided on one surface (hereinafter also referred to as "first surface") of a dielectric 201, and a second electrode 205 is provided on the surface opposite the first surface (hereinafter also referred to as "second surface"). In FIG. 2, reference numeral 206 denotes a dielectric substrate, and reference numeral 207 denotes a power supply. In the plasma generator 103, a first electrode 203 and a second electrode 205 are arranged diagonally opposite each other with a dielectric 201 sandwiched therebetween. By applying a voltage between these electrodes (between both electrodes), plasma 202 is generated from the first electrode 203 toward the second electrode 205, and a jet of surface plasma 202 flows from an edge 204 of the first electrode 203 along an exposed portion 201-1 of the first surface of the dielectric 201 (a portion not covered by the first electrode). A jet-like flow is induced. At the same time, an air suction flow is generated from the space inside the container toward the electrode. Electrons in the surface plasma 202 collide with oxygen molecules in the air, dissociating the oxygen molecules and generating oxygen atoms. The generated oxygen atoms then collide with undissociated oxygen molecules, generating ozone. Therefore, due to the interaction between the jet-like flow caused by the surface plasma 202 and the air suction flow, an induced flow 109 containing a high concentration of ozone is generated from the edge 204 of the first electrode 203 along the surface of the dielectric 201. The plasma generator 103 is disposed on a mounting table 104 so that an induced flow 109 is supplied to a processing surface 105-1 of the processing object 105 that is irradiated with ultraviolet light from the ultraviolet light source 102.

[0018] That is, in a sterilization apparatus according to one embodiment of the present disclosure, an ozone-containing induced flow 109 from a plasma generator 103 is supplied to a processing surface 105-1 of a processing object 105, thereby locally increasing the ozone concentration in a region near the processing surface 105-1, specifically, in a spatial region up to a height of approximately 1 mm from the processing surface 105-1 (hereinafter also referred to as the "surface region"). Therefore, there is no need to increase the ozone concentration in the space from the ultraviolet light source 102 to the surface region, and ultraviolet light can be prevented from attenuating before reaching the surface region. As a result, ozone present in the surface region is efficiently decomposed into active oxygen by ultraviolet light. Furthermore, as a result, active oxygen is generated on the processing surface 105-1 of the processing object or in a position very close to the processing surface 105-1. As a result, the processing surface 105-1 of the processing object 105 is placed in an active oxygen atmosphere generated in situ at the processing surface, and the processing surface is more reliably sterilized by the active oxygen.

[0019] <Electrodes and dielectrics> The materials constituting the first electrode and the second electrode are not particularly limited as long as they are materials with good conductivity. For example, metals such as copper, aluminum, stainless steel, gold, silver, and platinum, as well as metals plated or vapor-deposited on these, conductive carbon materials such as carbon black, graphite, and carbon nanotubes, and composite materials obtained by mixing these with resins, etc., can be used. The materials constituting the first electrode and the second electrode may be the same or different. Among these, from the viewpoint of avoiding electrode corrosion and achieving uniform discharge, the material constituting the first electrode is preferably aluminum, stainless steel, or silver.For the same reason, the material constituting the second electrode is also preferably aluminum, stainless steel, or silver. The first electrode and the second electrode may have any shape, such as a flat plate, a wire, or a needle, without any particular limitation. Preferably, the first electrode has a flat plate shape. Preferably, the second electrode has a flat plate shape. When at least one of the first electrode and the second electrode has a flat plate shape, the aspect ratio of the plate (length of long side / length of short side) is preferably 2 or more. A preferred embodiment of at least one of the first and second electrodes is one in which the apex angle is 45° or less (i.e., the electrode is sharp), but is not limited to this. Note that although the drawings show the first and second electrodes both having apex angles of 90°, embodiments in which the apex angle exceeds 45° are also included in the present disclosure. The dielectric is not particularly limited as long as it is a material with high electrical insulation. For example, resins such as polyimide, polyester, fluororesin, silicone resin, acrylic resin, and phenolic resin, glass, ceramics, and composite materials in which these are mixed with resin, etc. can be used. Among these, ceramics and glass are preferred because they can further increase the electric field strength.

[0020] <Plasma actuator> The plasma actuator has a first electrode and a second electrode sandwiched between them by a dielectric material. There are no particular limitations on the material, as long as it can generate an induced flow containing ozone by applying a voltage to the electrode. In a plasma actuator, the shorter the shortest distance between the first electrode and the second electrode, the easier it is to generate plasma. Therefore, the thinner the film thickness of the dielectric is, as long as it does not cause electrical breakdown, and can be 10 μm to 1000 μm, preferably 10 μm to 200 μm. Furthermore, the shortest distance between the first electrode and the second electrode is preferably 200 μm or less. 3 is an explanatory diagram of the overlap between the first electrode 203 and the second electrode 205 of the plasma actuator, which is an ozone generator, and is a cross-sectional view of the plasma actuator. When viewed from above in a cross-sectional view, the first electrode 203 and the second electrode 205 arranged diagonally opposite each other may have an edge of the first electrode located in the portion where the second electrode is formed, with a dielectric sandwiched between them. That is, the first electrode and the second electrode may be provided so as to overlap with each other, with a dielectric sandwiched between them. In this case, it is preferable to prevent dielectric breakdown when a voltage is applied in the portion where the first electrode and the second electrode overlap with the dielectric sandwiched between them. Furthermore, when the first electrode and the second electrode are far apart as viewed from above in the cross section, it is preferable to increase the voltage to compensate for the weakening of the electric field caused by the greater distance between the electrodes. It is more preferable that the overlap between the edge of the first electrode and the edge of the second electrode is -100 μm to +1000 μm as viewed from above in the cross section, assuming that the overlap length is positive. The thickness of the electrodes is not particularly limited for either the first electrode or the second electrode, but can be 10 μm to 1000 μm. If the thickness is 10 μm or more, the resistance is low and plasma generation becomes easier. If the thickness is 1000 μm or less, electric field concentration occurs easily, making plasma generation easier. The width of the electrodes is not particularly limited for both the first electrode and the second electrode, but can be 1000 μm or more. Furthermore, if the edge of the second electrode is exposed, plasma may also be generated from the edge of the second electrode, resulting in an induced flow in the opposite direction to the induced flow 109 originating from the first electrode. In the sterilization apparatus according to this embodiment, it is preferable to keep the ozone concentration in the internal space of the sterilization container other than the surface region of the object to be treated as low as possible. It is also preferable to prevent a gas flow that would disturb the flow of the induced flow 109 from being generated within the container. Therefore, it is preferable to prevent an induced flow originating from the second electrode from being generated. Therefore, it is preferable that the second electrode 205 is covered with a dielectric such as a dielectric substrate 206 as shown in FIGS. 2 and 3, or is embedded in a dielectric 201 to prevent plasma generation from the edge of the second electrode.

[0021] Induced flow 109 containing high-concentration ozone flows in the direction of a jet-like flow caused by surface plasma from edge 204 of first electrode 203 along exposed portion 201-1 of the first surface of dielectric 201, that is, in the direction from edge 204 of first electrode 203 along exposed portion 201-1 of the first surface of the dielectric. This induced flow is a gas flow containing high-concentration ozone, with a speed of several m / s to several tens of m / s. The voltage applied between the first electrode 203 and the second electrode 205 of the plasma actuator is not particularly limited as long as it can generate plasma in the plasma actuator. Although either a DC voltage or an AC voltage may be used, an AC voltage is preferred. It is also a preferred embodiment that the voltage is a pulse voltage. Furthermore, the amplitude of the voltage can be 1 kV to 100 kV. Furthermore, the frequency of the voltage can be preferably 1 kHz or higher, more preferably 10 kHz to 100 kHz. When the voltage is an AC voltage, the waveform of the AC voltage is not particularly limited, and a sine wave, square wave, triangular wave, etc. can be used, but a square wave is preferable from the viewpoint of the speed of the voltage rise. The duty ratio of the voltage can also be selected appropriately, but it is preferable that the voltage rises quickly. Preferably, the voltage is applied so that the rise time of the voltage from the bottom to the peak of the wavelength amplitude is 4,000,000 V / second or more. The value (voltage / film thickness) obtained by dividing the amplitude of the voltage applied between the first electrode 203 and the second electrode 205 by the film thickness of the dielectric 201 is preferably 10 kV / mm or more.

[0022] <Ultraviolet light source and ultraviolet light> The ultraviolet light source is not particularly limited as long as it can irradiate ultraviolet light capable of exciting ozone and generating active oxygen. However, since the peak value of the light absorption spectrum of ozone is 260 nm, the peak wavelength of the ultraviolet light is preferably 220 nm to 310 nm, more preferably 253 nm to 285 nm, and even more preferably 253 nm to 266 nm. Specific examples of ultraviolet light sources that can be used include low-pressure mercury lamps, which are made by sealing mercury together with an inert gas such as argon or neon inside quartz glass, cold cathode ultraviolet lamps (UV-CCL), and ultraviolet LEDs. The wavelength of the low-pressure mercury lamp or cold cathode ultraviolet lamp should be selected from 254 nm or the like. On the other hand, the wavelength of the ultraviolet LED should be selected from 265 nm, 275 nm, 280 nm, etc., from the viewpoint of output performance.

[0023] <Arrangement of plasma generator, ultraviolet light source, and workpiece> The position of the plasma generating device 103 that generates an induced flow containing ozone within the sterilization container 112 is arranged so that the induced flow 109 containing ozone is supplied to the treatment surface 105-1 of the workpiece to be sterilized, in order to increase the ozone concentration in the surface region of the workpiece. For example, the plasma generator and the object to be treated may be arranged so that the induced flow 109 containing high concentration ozone is supplied to the surface of the object to be treated over the shortest distance. Also, for example, the plasma actuator may be arranged so that the processing surface 105-1 of the workpiece is included on an extension line extending from the edge of the first electrode of the plasma actuator in a direction along the exposed portion 201-1 of the first surface of the dielectric. Furthermore, the angle formed by an extension line extending from the edge of the first electrode of the plasma actuator along the exposed portion 201-1 of the first surface of the dielectric with respect to the processing surface 105-1 of the workpiece (also referred to as the plasma actuator incident angle, or PA incident angle) is preferably 0° to 45°, and more preferably 0° to 30°. By arranging the plasma generating device and the workpiece as described above, an ozone-containing induced flow having a certain flow velocity can be supplied locally to a region near the surface of the workpiece.

[0024] The ultraviolet light source is not particularly limited as long as it is positioned so as to be able to irradiate the surface of the object to be sterilized. As described above, since the induced flow containing ozone is supplied to the region near the surface of the workpiece, the ozone concentration near the surface can be locally increased. This prevents the ultraviolet light from the ultraviolet light source from being absorbed by the ozone and attenuated before reaching the surface region, and as a result, the ozone present in the surface region is efficiently decomposed into active oxygen by the ultraviolet light. The distance between the ultraviolet light source and the object to be treated is preferably 3 cm or less, and more preferably 1 cm or less. However, it is not necessary to place the object to be treated within about 1 cm of the ultraviolet light source, and one device can sterilize the surfaces of objects of various sizes and thicknesses. It is also a preferred embodiment to provide a moving means for at least one of the ultraviolet light source and the object to be treated, so that at least one of the ultraviolet light source and the object to be treated can be moved freely so that the illuminance becomes uniform. Furthermore, the angle formed by the ultraviolet light emitted from the ultraviolet light source and an extension line from the edge of the first electrode of the plasma actuator along the surface of the dielectric, with the object to be treated as the vertex, is preferably 45° to 180°. When this angle is 45° to 180°, the UV light and ozone can be prevented from becoming active oxygen before reaching the object to be treated, further improving the sterilization effect. Furthermore, the illuminance is 100 μW / cm at the intersection of an extension line extending from the edge of the first electrode of the plasma actuator in a direction along the surface of the dielectric and the ultraviolet light irradiated from the ultraviolet light source (i.e., a position corresponding to the surface of the workpiece where the ultraviolet light from the ultraviolet light source is irradiated). 2 Furthermore, it is preferable to generate an induced flow with an ozone concentration of 20 ppm or more at the intersection of an extension line extending from the edge of the first electrode of the plasma actuator in a direction along the surface of the dielectric and the ultraviolet light irradiated from the ultraviolet light source (i.e., a position of the ultraviolet light from the ultraviolet light source corresponding to the surface of the object to be treated).

[0025] 6 to 8 show the configuration of an active oxygen supplying device 600 according to one embodiment of the present disclosure. The reference numerals 102, 103, 105, 105-1, and 109 in FIGS. 6 to 8 are the same as those in FIG. 1. The active oxygen supplying device shown in FIGS. 6 to 8 includes a housing 601 having at least one opening 605, and an ultraviolet light source 102 and a plasma actuator 103 are disposed inside the housing. The plasma actuator 103 is disposed so that an induced flow 109 containing ozone from the plasma actuator flows out of the housing through the opening 605. The ultraviolet light source 102 is disposed so that the ultraviolet light emitted from the ultraviolet light source is irradiated onto the induced flow 109. The induced flow irradiated with ultraviolet light excites the ozone in the induced flow, causing it to contain active oxygen. As a result, the induced flow containing active oxygen flows out from the opening. At this time, by placing the workpiece 105 in contact with the opening, active oxygen is actively supplied to the surface 105-1 to be treated, and the surface can be actively placed in an active oxygen atmosphere. Furthermore, by placing the workpiece 105 close to the opening, the induced flow flowing out from the opening flows along the surface of the workpiece (see reference numeral 109-1 in FIG. 7), and parts of the workpiece surface other than the part facing the opening are also exposed to the induced flow containing active oxygen. This allows a wider area of ​​the workpiece surface 105-1 to be treated with active oxygen. The above descriptions are incorporated by reference for the plasma actuator according to this embodiment, the electrodes and dielectrics used therein, and the ultraviolet light source and ultraviolet light.

[0026] Here, the ultraviolet light source irradiates the induced flow with light containing ultraviolet light, generates active oxygen in the induced flow, and supplies the induced flow containing an effective amount of active oxygen according to the purpose of the treatment to the workpiece through the opening. The intensity and position of the ultraviolet light source relative to the plasma generator may be set so that, for example, the distance from the surface of the dielectric of the plasma actuator facing the ultraviolet light source is 10 mm or less, and particularly 4 mm or less. Furthermore, for example, the intensity of the light containing ultraviolet light may be 40 μW / cm or less, and the illuminance on the surface of the dielectric of the plasma actuator facing the ultraviolet light source may be 40 μW / cm or less. 2 Above 100 μW / cm 2The upper limit of the illuminance is not particularly limited, but it is preferably 10,000 μW / cm 2 It is preferable to do the following:

[0027] Furthermore, the distance between the plasma actuator and the opening is preferably short so that the active oxygen in the induced flow can be used more effectively for the target treatment. Therefore, it is preferable to position the plasma actuator closer to the opening. On the other hand, to protect the plasma actuator, it is also preferable to position it at a setback from the opening. As an example, it is preferable to position the plasma actuator on the inner wall of the housing so that the end of the plasma actuator closest to the opening is located 0.5 mm to 1.5 mm from the edge of the opening on the inner wall of the housing.

[0028] Furthermore, in the active oxygen supply device according to this embodiment, the positions of the plasma generator 103 and the ultraviolet light source 102 that generate the ozone-containing induced flow are not particularly limited, as long as active oxygen is generated in the induced flow by the light containing ultraviolet light from the ultraviolet light source, and an induced flow containing an effective amount of active oxygen according to the purpose of the treatment flows out from the opening and is supplied to the surface to be treated.

[0029] In this embodiment, the flow velocity of the induced flow from the opening is not particularly limited, as long as an induced flow containing an effective amount of active oxygen is supplied to the surface to be treated, depending on the distance of the workpiece from the opening and the purpose of the treatment. For example, when the plasma actuator is disposed within the housing so that the end of the plasma actuator closest to the opening is located 0.5 to 1.5 mm from the edge of the opening in the inner wall of the housing, as described above, and the surface of the workpiece to be treated is positioned 0.5 to 2 mm from the surface of the housing having the opening, the preferred flow velocity of the organic flow at the opening is 0.01 to 100 m / s. This flow velocity can be adjusted by the material of the dielectric and the voltage conditions applied to the electrodes of the plasma actuator. The higher the volume resistivity of the dielectric, the stronger the electric field strength, which in turn increases the flow velocity of the induced flow from the plasma actuator. Therefore, as described above, ceramics such as glass are more preferably used as the dielectric. The preferred voltage conditions are as described above.

[0030] 6 to 8, the active oxygen supplying device is configured so that the ultraviolet rays are not directly irradiated onto the surface to be treated by the housing, but a configuration in which the surface to be treated is also directly irradiated is also within the scope of a modified example of this embodiment. In this case, active oxygen can be generated in situ on the surface to be treated, and further improvement in the treatment efficiency of the surface to be treated is expected. In a sterilization treatment using only ultraviolet light, only the surface irradiated with ultraviolet light is sterilized. However, in a sterilization treatment using the active oxygen supplying device according to the present disclosure, bacteria present in positions that can be reached by active oxygen can be sterilized. Therefore, for example, even bacteria present between fibers, which are difficult to sterilize by external ultraviolet light irradiation, can be sterilized. [Example]

[0031] The present disclosure will be described in more detail below using examples and comparative examples, but the aspects of the present disclosure are not limited thereto.

[0032] Example 1 1. Preparation of sterilization device A first electrode was formed by attaching a piece of aluminum foil measuring 18 mm in length, 9.5 mm in width, and 100 μm in thickness to a first surface of a glass plate (18 mm in length, 18 mm in width, and 150 μm in thickness) using adhesive tape, so that an area measuring 18 mm in length and 3 mm in width on the first surface of the glass plate was exposed. A second electrode was formed by attaching a piece of aluminum foil measuring 18 mm in length, 9 mm in width, and 100 μm in thickness to a second surface of the glass plate using adhesive tape, so that it was diagonally opposite the aluminum foil attached to the first surface. Furthermore, the second surface, including the second electrode, was covered with polyimide tape. In this way, a plasma actuator was fabricated in which the first electrode and the second electrode were arranged to overlap over a width of 0.5 mm, sandwiching the dielectric (glass plate) between them. As shown in Fig. 4, this plasma actuator was placed on a mounting table 403 inside a sterilization container 112 measuring 15 cm in length, 10 cm in width, and 7 cm in height, with the first electrode facing vertically upward and the surface (201-1) of the glass plate on which the first electrode was formed and which was not covered with the first electrode facing horizontally. Fig. 4(a) is a schematic cross-sectional view of the sterilization apparatus according to this example, and Fig. 4(b) is a plan view. In addition, a table 110 for placing objects to be sterilized was placed inside the sterilization apparatus. The table 110 was placed so that the surface to be treated of the evaluation sample (described later) was horizontal, flush with the surface of the dielectric of the plasma actuator 103 on which the first electrode was formed and not covered with the first electrode, and so that the distance between the edge of the first electrode and the center of the object to be treated (LPA in FIG. 4(a)) was 5 cm. Furthermore, a cold cathode ultraviolet lamp (product name: UW / 9F89 / 9, manufactured by Stanley Electric Co., Ltd., peak wavelength: 254 nm) was prepared as an ultraviolet light source. The distance between the cold cathode ultraviolet lamp and the target surface (LUV in Fig. 4(a)) was 3 cm, and the incident angle of the ultraviolet light to the center of the target surface (θUV in Fig. 4(a)) was 90°. For this sterilization device, an illuminance meter (trade name: Spectroradiometer USR-45D, manufactured by Ushio Inc.) was placed at the position of the surface to be treated when the evaluation sample was placed on the mounting table, and the illuminance of ultraviolet light was measured. The integrated value of the spectrum was 487 μW / cm 2 It was. Furthermore, 50 ml of gas was sampled at the position of the treated surface when the evaluation sample was placed on the mounting table after applying a voltage having a sine waveform with an amplitude of 2.4 kV and a frequency of 80 kHz to the plasma actuator. The sampled gas was drawn into an ozone detector tube (product name: 182SB, manufactured by Komyo Rikagaku Kogyo Co., Ltd.) and the ozone concentration in the induced flow from the plasma actuator was measured, which was 40 ppm (reading value x 2). 50 ml of gas was also sampled at the midpoint between the treated surface and the ultraviolet light source (LUV / 2). The sampled gas was drawn into an ozone detector tube (product name: 182SB, manufactured by Komyo Rikagaku Kogyo Co., Ltd.) and the ozone concentration was measured, which was 8 ppm (reading value x 2).

[0033] 2. Preparation of evaluation samples A stamp medium (product name: Petan Check 25 PT1025, manufactured by Eiken Kasei Co., Ltd.) was applied at 25g / cm to door knobs that had not been wiped down with water or alcohol for a week and where an unspecified number of people had been entering and exiting. 2 After pressing the stamp with a pressure of 10 seconds, The medium was then placed in an environment at 37°C for 12 hours. Colonies grown on the stamp medium were collected using a sterile cotton swab and dispersed in distilled water to prepare a bacterial suspension. This bacterial suspension was diluted 10-fold with distilled water, and 0.1 ml of the diluted bacterial suspension was smeared onto a new stamp medium (Petan Check 25 PT1025, Eiken Kasei Co., Ltd.) and placed in an environment at 37°C for 12 hours. As a result, bacterial growth of 200 to 300 CFU / ml was confirmed. Therefore, 0.1 ml of the diluted bacterial solution was smeared onto a new stamp medium (Petan Check 25 PT1025, manufactured by Eiken Kasei Co., Ltd.) to prepare a sample for evaluation.

[0034] 3. Disinfection test The evaluation sample 401 prepared in 2 was placed on the mounting table 110 of the sterilization device prepared in 1. Next, a voltage having a sine waveform with an amplitude of 2.4 kV and a frequency of 80 kHz was applied to the plasma actuator, and ultraviolet light was irradiated to perform a sterilization treatment for 5 minutes. The evaluation sample was then removed from the sterilization device and cultured at a temperature of 37°C for 12 hours. The number of surviving bacteria was calculated from the number of colonies grown on the medium. The sterilization test was performed three times, and the average value multiplied by 10 was used as the colony count in the sterilization test of this example. The sterilization performance was evaluated from the obtained colony count using the following criteria (Ten Cate's evaluation and display method). -: No growth ±: Number of colonies <10 +: 10 to 29 colonies ++: 30 to 100 colonies +++: Number of colonies > 100 ++++: Infinite number of colonies

[0035] <Examples 2 to 5> A sterilization device was produced and evaluated in the same manner as in Example 1, except that the ultraviolet light source and the dielectric thickness of the plasma actuator were changed as shown in Table 1. In Example 2, an ultraviolet LED (peak wavelength 280 nm) was used as the ultraviolet light source.

[0036] <Comparative Examples 1 to 3> Comparative Examples 1 to 3 were configured as follows, but were otherwise the same as Example 1. Comparative Example 1: No voltage was applied to the plasma actuator and no ultraviolet light was irradiated. Comparative Example 2: No voltage was applied to the plasma actuator, and ultraviolet light was irradiated for 5 minutes. Comparative Example 3: A voltage was applied to the plasma actuator for 5 minutes, and no ultraviolet light was irradiated.

[0037] <Comparative Example 4> In the sterilization device of Example 1, the plasma actuator was positioned so that the induced flow would flow on the opposite side of the object to be treated, as shown in Figure 5, and the distance between the edge of the first electrode and the center of the object to be treated was 10 cm, and the distance between the ultraviolet light source and the surface of the object to be treated was 3 cm. Then, a voltage was applied to the plasma actuator under the same conditions as in Example 1, and the sterilization container was filled with ozone so that the ozone concentration in the surface area of ​​the treatment surface was 40 ppm. Thereafter, the evaluation sample was moved from the preliminary chamber into the sterilization chamber and placed on the mounting table so that the ozone concentration in the sterilization container would not decrease. Subsequently, ultraviolet light was irradiated from the ultraviolet light source toward the evaluation sample in the same manner as in Example 1, and a sterilization treatment was carried out for 5 minutes. Subsequent operations were performed in the same manner as in Example 1, and the culture was cultured, and the number of grown colonies was counted and evaluated.

[0038] [Table 1] In the table, PA stands for plasma actuator and UV stands for ultraviolet light.

[0039] Example 6 1. Preparation and Characterization of an Active Oxygen Treatment Device First, a housing 601 of an active oxygen supplying device 600 shown in FIG. 7 was prepared. FIG. 6 is a plan view of the active oxygen supplying device shown in FIG. 7, seen from the side of the housing 601 having an opening 605. The size of the housing, when placed so that the opening 605 faces vertically downward, was 20 mm in height, 150 mm in depth, and 20 mm in width. The opening 605 was 7 mm in width and 15 mm in length. The opening 605 was provided so that its longitudinal direction coincided with the depth direction of the housing, as shown in FIG. 6. Further, plasma actuator 103 was fabricated in the same manner as in Example 1. Next, plasma actuator 103 was fixed to the inner wall of housing 601, as shown in FIG. 7. Specifically, one end of first electrode 203 of plasma actuator 103 was fixed in a position horizontally aligned with the center of ultraviolet light source 102, and induced flow 109 from plasma actuator 103 was fixed so that it would flow out through opening 605. Here, the distance between the surface of plasma actuator 103 facing the ultraviolet light source and ultraviolet light source 102 (reference numeral 607 in FIG. 8) was 2 mm, and the distance from the bottom end of plasma actuator 103 to the bottom end of opening 605 (outside the housing) (reference numeral 609 in FIG. 8) was 1 mm. As in Example 1, a cold-cathode ultraviolet lamp (product name: UW / 9F89 / 9, manufactured by Stanley Electric Co., Ltd., peak wavelength = 254 nm) was used as ultraviolet light source 102. For the active oxygen supply device 600 obtained in this way, an illuminance meter (trade name: Spectroradiometer USR-45D, manufactured by Ushio Inc.) was placed on the surface of the glass plate 201 of the plasma actuator 103 facing the ultraviolet lamp to measure the illuminance of ultraviolet light. The integrated value of the spectrum was 1370 μW / cm 2 In addition, when the illuminance meter was placed in contact with the opening 605, The UV irradiance is 0.3 μW / cm 2 This indicates that the ultraviolet light coming from the opening It was confirmed that there was virtually no leakage.

[0040] Next, to avoid the influence of ozone decomposition by ultraviolet light, the ultraviolet lamp was turned off and a voltage having a sine waveform with an amplitude of 2.4 kV and a frequency of 80 kHz was applied between both electrodes of plasma actuator 103. After 5 minutes, 50 ml of the induced flow flowing out from the opening was sampled. The sampled gas was drawn into an ozone detector tube (product name: 182SB, manufactured by Komyo Rikagaku Kogyo Co., Ltd.), and the ozone concentration in the induced flow from the plasma actuator was measured, which was 70 ppm (reading value x 2). Next, a voltage having a sine waveform with an amplitude of 2.4 kV and a frequency of 80 kHz was applied between both electrodes of the plasma actuator, and the ultraviolet lamp was turned on so that the illuminance on the surface of the glass plate 201 of the plasma actuator 103 facing the ultraviolet lamp was 1370 μW / cm 2 The ultraviolet lamp was turned on so that the ozone concentration in the induced flow flowing out of the opening was measured in the same manner as above. The result was 18 ppm. From these results, it is believed that the induced flow contains active oxygen resulting from the decomposition of 52 ppm of ozone by ultraviolet light.

[0041] 2-1. Treatment (sterilization) test (1) Preparation of samples for sterilization tests In Example 1, three evaluation samples were prepared for the verification test of sterilization performance. As in Example 1, a stamp medium (trade name: Petan Check 25 PT1025, manufactured by Eiken Kasei Co., Ltd.) was applied at 25 g / cm to a door knob that was used by an unspecified number of people and had not been wiped down with water, alcohol, or the like for a week. 2 After pressing the stamp medium with a pressure of 0.01 mm for 10 seconds, the stamp medium was placed in an environment at 37°C for 12 hours. Colonies grown on the stamp medium were collected using a sterile cotton swab and dispersed in distilled water to prepare a bacterial suspension. This bacterial suspension was diluted 10-fold with distilled water, and 0.1 ml of the diluted bacterial suspension was smeared on a new stamp medium (Petan Check 25PT1025, Eiken Kasei Co., Ltd.) and placed in an environment at 37°C for 12 hours. As a result, bacterial growth of 200 to 300 CFU / ml was observed. Therefore, 0.1 ml of the diluted bacterial suspension was smeared on the entire surface of a glass plate (15 mm long, 15 mm wide, 2 mm thick) whose surface had been cleaned with 70% alcohol. The plate was then placed in an environment at 37°C for 1 hour to remove moisture. In this way, a total of three samples for the sterilization test were prepared.

[0042] (2) Sterilization test An active oxygen supplying device was installed on the surface to be treated of each sample so that the distance (reference numeral 611 in FIG. 8) between the surface (external surface) having the opening of the housing and the surface to be treated was 2 mm. At this time, the center position in the width direction (left and right direction in FIG. 8) of the sample was aligned with the center position in the width direction of the opening, and the center position in the depth direction (depth direction into the paper in FIG. 8) of the sample was also aligned with the center position in the longitudinal direction of the opening. Next, a voltage having a sine waveform with an amplitude of 2.4 kV and a frequency of 80 kHz was applied to the plasma actuator, and the illuminance on the surface of glass plate 201 of plasma actuator 103 facing the ultraviolet lamp was adjusted to 1370 μW / cm. 2 The ultraviolet lamp was turned on so that the ultraviolet light was irradiated onto the induced flow for 30 seconds, and the induced flow containing active oxygen was discharged from the opening, supplying active oxygen to the treated surface (treatment time: 30 seconds). Next, a stamp medium (product name: Petan Check 25 PT1025, manufactured by Eiken Kasei Co., Ltd.) was applied to the treated surface of the sample at a density of 25 g / cm. 2 After pressing the stamp medium against the plate for 10 seconds with a pressure of 1000 kJ / cm, the stamp medium was placed in an environment at a temperature of 37°C for 12 hours. The number of colonies that grew on the stamp medium was then counted. The number of surviving bacteria was calculated from the above. The average number of surviving bacteria obtained from each sample was multiplied by 10 to obtain the number of colonies in the sterilization test according to this example. The sterilization performance was evaluated from the obtained number of colonies according to the following criteria (Ten Cate's evaluation and display method). -: No growth ±: Number of colonies <10 +: 10 to 29 colonies ++: 30 to 100 colonies +++: Number of colonies > 100 ++++: Infinite number of colonies

[0043] 2-2. Treatment (bleaching) test (1) Preparation of bleaching test samples Chili sauce (trade name: Pepper Sauce, manufactured by Tabasco) was filtered through a long-fiber nonwoven fabric (trade name: Bemcot M-3II, manufactured by Asahi Kasei Corporation) to remove solids. A paper wiper (trade name: Kimwipe S-200, manufactured by Nippon Paper Crecia Co., Ltd.) was immersed in the resulting liquid for 10 minutes. The paper wiper was then removed and washed with water. Washing with water was repeated until the wash liquid was no longer visually colored. The wiper was then dried. Next, three samples measuring 15 mm in length and 15 mm in width were cut from the paper wiper dyed red with the chili sauce.

[0044] (2) Bleaching test An active oxygen supplying device was installed on each sample so that the distance (reference numeral 611 in FIG. 8) between the surface (external surface) having the opening of the housing and the surface to be treated was 2 mm. At this time, the center position in the width direction (left and right direction in FIG. 8) of the sample was aligned with the center position in the width direction of the opening, and the center position in the depth direction (depth direction into the paper in FIG. 8) of the sample was also aligned with the center position in the longitudinal direction of the opening. Next, a voltage having a sine waveform with an amplitude of 2.4 kV and a frequency of 80 kHz was applied to the plasma actuator, and the illuminance on the surface of glass plate 201 of plasma actuator 103 facing the ultraviolet lamp was set to 1370 μW / cm. 2 The ultraviolet lamp was turned on so that the ultraviolet light was irradiated onto the induced flow for 20 minutes, supplying the induced flow containing active oxygen to a part of the treated surface (treatment time: 20 minutes). Next, the active oxygen supply device was removed from the treated surface, and the degree of decolorization was visually observed compared with the sample before treatment, and evaluated according to the following criteria. A: Completely bleached. B: There was still a slight red hue from the chili sauce. C: There was still some red color left from the chili sauce. D: There was no difference in color from the area where active oxygen was not supplied.

[0045] 2-3. Treatment (deodorization) test (1) Preparation of deodorizing test samples A paper wiper (Kimwipe S-200, manufactured by Nippon Paper Crecia Co., Ltd.) was immersed in Fabric Mist (product name: Fabric Mist Linen, manufactured by Sabon Co., Ltd.) for 10 minutes, then removed and air-dried for 6 hours. Three samples measuring 15 mm in length and 15 mm in width were then cut out from the paper wiper.

[0046] (2) Deodorization test The active oxygen treatment device was placed on the surface to be treated of each sample so that the distance (reference numeral 611 in FIG. 8) between the surface (external surface) having the opening of the housing and the surface to be treated was 2 mm. At this time, the center position in the width direction (left and right direction in FIG. 8) of the sample was aligned with the center position in the width direction of the opening, and the center position in the depth direction (depth direction in FIG. 8) of the sample was also aligned with the center position in the longitudinal direction of the opening. Next, a voltage having a sine waveform with an amplitude of 2.4 kV and a frequency of 80 kHz was applied to the plasma actuator, and the rotation of plasma actuator 103 was The illuminance on the surface of the glass plate 201 facing the ultraviolet lamp is 1370 μW / cm 2 The ultraviolet lamp was turned on so that the induced flow was irradiated with ultraviolet light for 20 seconds, supplying the induced flow containing active oxygen to the treated surface (treatment time: 20 seconds). Next, the active oxygen supply device was removed from above the sample. The odor of the treated sample was evaluated using the following intensity criteria to see how much it remained compared to a sample that had not been treated with active oxygen. The evaluation was conducted on five subjects, and the intensity criteria selected by at least three subjects were used. A: Odorless. B: An odor that can just be detected (detection threshold). C: A weak odor (recognition threshold) that can be identified as the odor of fabric mist. D: No difference from untreated sample.

[0047] <Comparative Examples 5 to 7> Comparative Examples 5 to 7 were conducted under the same conditions as Example 6, except that the following configurations were used. Comparative Example 5: No voltage was applied to the plasma actuator and no ultraviolet light was irradiated. Comparative Example 6: No voltage was applied to the plasma actuator, and ultraviolet light was irradiated for 2 minutes. Comparative Example 7: A voltage was applied to the plasma actuator for 2 minutes, and no ultraviolet light was irradiated.

[0048] [Table 2]

[0049] 2-4. Treatment (sterilization of E. coli) test (1) Using the active oxygen supply device used in Example 6, a sterilization test for Escherichia coli was carried out according to the following procedure. All instruments used in this sterilization test were sterilized with high-pressure steam using an autoclave. This sterilization test was also carried out in a clean bench. First, E. coli (trade name "KWIK-STIK (Escherichia coli) ATCC8739), manufactured by Microbiologics) was placed in an Erlenmeyer flask containing LB medium (2 g of tryptone, 1 g of yeast extract, 1 g of sodium chloride, and distilled water to make 200 ml), and cultured at 37°C for 48 hours with shaking at 80 rpm. After the culture, the E. coli bacterial solution contained 9.2 x 10 9 (CFU / ml). After this incubation, 0.010 ml of the bacterial solution was dropped onto a 3 cm long, 1 cm wide, and 1 mm thick glass slide (Matsunami Glass, model number: S2441) using a micropipette, and the bacterial solution was applied to the entire surface of one side of the glass slide with the tip of the micropipette to prepare sample No. 6-1. Similarly, samples No. 6-2 to 6-3 were prepared.

[0050] Next, sample No. 6-1 was immersed in a test tube containing 10 ml of buffer solution (trade name "Gibco PBS", Thermo Fisher Scientific) for 1 hour. Note that the time from dropping the bacterial solution onto the slide glass to immersing it in the buffer solution was set to 60 seconds to prevent the bacterial solution on the slide glass from drying out. Next, 1 ml of the buffer solution (hereinafter also referred to as "1 / 1 solution") after immersion of sample No. 6-1 was added to 9 A dilution (hereinafter referred to as "1 / 10 dilution") was prepared by placing the diluted solution in a test tube containing 1 ml of buffer. 1 / 100, 1 / 1000, and 1 / 10000 dilutions were prepared in the same manner, except that the dilution ratio with buffer was changed. Next, 0.050 ml of the 1 / 1 solution was taken and smeared onto a stamp medium (Petan Check 25 PT1025, Eiken Kasei Co., Ltd.). This procedure was repeated to create two stamp media smeared with the 1 / 1 solution. The two stamp media were placed in an incubator (trade name: IS600, Yamato Scientific Co., Ltd.) and cultured at 37°C for 24 hours. The number of colonies that appeared on the two stamp media was counted, and the average was calculated. Two smeared stamp plates were prepared for each of the 1 / 10, 1 / 100, 1 / 1000, and 1 / 10,000 dilutions in the same manner as above, and cultured. The number of colonies that appeared on each stamp plate for each dilution was counted, and the average was calculated. The results are shown in Table 3.

[0051] [Table 3]

[0052] From the results shown in Table 3 above, the number of colonies when the 1 / 10000 diluted solution was cultured was 21. Therefore, the number of bacteria present in 0.050 ml of the 1 / 1 solution of sample No. 6-1 was 21 x 10 4 =210,000 (CFU).

[0053] Next, the following operations were carried out on Samples Nos. 6-2 and 6-3. A recess measuring 3.5 cm in length, 1.5 cm in width, and 2 mm in depth was made in the center of a 30 cm long, 30 cm wide, and 5 mm thick plastic plate. Each sample slide was placed in the recess so that the surface of the slide opposite the bacterial suspension-applied surface was in contact with the bottom of the recess. An active oxygen supplying device was then placed on top of the plastic plate so that the longitudinal center of its opening coincided with the longitudinal center of the recess, and the widthwise center of the opening coincided with the lateral center of the recess. Because the recess was 2 mm deep and the slide was 1 mm thick, there was no direct contact between the bacterial suspension-applied surface of each sample and the opening of the active oxygen supplying device. Next, the active oxygen supplying device was activated, and the bacterial solution-coated surface of the slide glass was treated with an induced flow containing active oxygen. The treatment time was 2 seconds for Sample No. 6-2 and 10 seconds for Sample No. 6-3. In addition, to prevent the bacterial solution on the slide glass from drying during the treatment process using the active oxygen supplying device, the time from dropping the bacterial solution onto the slide glass to immersing it in the buffer solution was set to 60 seconds.

[0054] Each of the treated samples Nos. 6-2 and 6-3 was immersed in a test tube containing 10 ml of buffer solution (trade name "Gibco PBS"; Thermo Fisher Scientific) for 1 hour. Next, 1 ml of the buffer solution (hereinafter referred to as "1 / 1 solution") after immersion of each sample was added to a test tube containing 9 ml of buffer solution to prepare a dilution solution (1 / 10 dilution solution). Similarly, 1 / 100 dilution solution, 1 / 1000 dilution solution, and 1 / 10000 dilution solution were prepared, except that the dilution ratio with the buffer solution was changed. Next, 0.050 ml of each sample was taken from the 1 / 1 solution and smeared on a stamp medium (trade name: Petan Check 25 PT1025, manufactured by Eiken Kasei Co., Ltd.). For each sample, two stamp plates were prepared by smearing the 1 / 1 solution. A total of four stamp plates were placed in an incubator (product name: IS600; manufactured by Yamato Scientific Co., Ltd.) and cultured at 37°C for 24 hours. The number of colonies that appeared on each stamp plate containing the 1 / 1 solution for each sample was counted, and the average value was calculated. For each sample, two smeared stamp plates were prepared and cultured in the same manner as above for the 1 / 10, 1 / 100, 1 / 1000, and 1 / 10,000 dilutions. The number of colonies that appeared on each stamp plate for each dilution was then counted and the average value calculated. The results are shown in Table 4.

[0055] [Table 4]

[0056] From the number of colonies in the 1 / 1000 diluted solution of sample No. 6-2 after treatment, the number of bacteria in 0.050 ml of the 1 / 1 solution of sample No. 6-2 after treatment was 5 x 10 3 = 5000 (CFU). Therefore, in this example, the sterilization rate of E. coli when the treatment time was 2 seconds was 97.6% (= (210000 - 5000) / 210000 × 100). Furthermore, from the colony count of the 1 / 1 solution of sample No. 6-3 after treatment, it was found that the number of bacteria in 0.050 ml of the 1 / 1 solution of sample No. 6-3 after treatment was 0 (CFU). Therefore, in this example, the elimination rate of E. coli when the treatment time was 10 seconds was 99.999% (= (210000-1) / 210000 x 100) or more.

[0057] (2) Samples C6-1 to C6-2 were prepared in the same manner as Sample No. 6-1 above. These samples were treated in the same manner as in (1) above, except that the ultraviolet lamp of the activated oxygen supply device was not turned on. Therefore, Samples C6-1 and C6-2 were treated with ozone in the induced flow. The treatment time was 2 seconds for Sample No. C6-1 and 10 seconds for Sample No. C6-2. After treatment, Samples C6-1 to C6-2 were immersed in a buffer solution and diluted in the same manner as Sample No. 6-1 in (1) above. Next, two smeared stamp media were prepared and cultured for each of the 1 / 1, 1 / 10, 1 / 100, 1 / 1000, and 1 / 10,000 diluted solutions of Samples C6-1 and C6-2, respectively, in the same manner as Sample No. 6-1 in (1) above. The number of colonies that appeared on each stamp medium for the 1 / 1 solution and each dilution of each sample was counted, and the average value was calculated. The results are shown in Table 5.

[0058] [Table 5]

[0059] From the results above, the culture results of the 1 / 10000 diluted solution of the treated sample No. C6-1 showed that the number of bacteria present in 0.050 ml of the 1 / 1 solution of the treated sample No. C6-1 was 19 x 10 4 = 190,000 (CFU). Therefore, in the experimental example using sample No. C6-1, the sterilization rate of E. coli was 9.5% (= (210,000 - 190,000) / 210,000 × 100). In addition, from the culture results of the 1 / 10000 diluted solution of the treated sample No. C6-2, the number of bacteria present in 0.050 ml of the 1 / 1 solution of the treated sample No. C6-2 was 8 x 10 4 = 80,000 (CFU). Therefore, in the experimental example using sample No. C6-2, the sterilization rate of E. coli was 61.9% (= (210,000 - 80,000) / 210,000 x 100).

[0060] From the above results, it was confirmed that treatment using active oxygen can more reliably eliminate E. coli in a shorter time than treatment using ozone alone.

[0061] (3) In the preparation of sample No. 6-1, the slide glass was replaced with a qualitative filter paper (product number: No. 5C, manufactured by Advantec Co., Ltd.) measuring 3 cm in length and 1 cm in width. The bacterial solution was only dropped onto one side of the filter paper. Other than these, samples No. 7-1 and 7-2 were prepared in the same manner as sample No. 6-1. Next, the following procedure was carried out on sample No. 7-1. A recess measuring 3.5 cm in length, 1.5 cm in width, and 2 mm in depth was created in the center of a 30 cm long, 30 cm wide, and 5 mm thick plastic plate. A 3.5 cm long, 1.5 cm wide filter paper was placed in the recess. Sample No. 7-1 was placed on the filter paper with its bacterial solution droplet facing the filter paper placed at the bottom of the recess. An active oxygen supplying device was then placed on top of the plastic plate so that the longitudinal center of its opening coincided with the longitudinal center of the recess and the widthwise center of the opening coincided with the lateral center of the recess. Because the recess depth was 2 mm and the filter paper thickness was less than 1 mm, there was no direct contact between the bacterial solution-adhered surface of each sample and the opening of the active oxygen supplying device. The active oxygen supplying device was then activated, and the bacterial solution-adhered surface of the filter paper was treated with an induced flow containing active oxygen. The treatment time was 10 seconds. In addition, in the treatment process using the active oxygen supply device, the time from dropping the bacterial solution onto the filter paper to immersing it in the buffer solution was set to 60 seconds so that the filter paper onto which the bacterial solution had been dropped would not dry out.

[0062] After the treatment, Sample No. 7-1, together with the filter paper placed at the bottom of the well, was immersed in a test tube containing 10 ml of buffer solution (trade name "Gibco PBS"; Thermo Fisher Scientific) for 1 hour. Next, 1 ml of the immersed buffer solution (hereinafter referred to as "1 / 1 solution") was added to a test tube containing 9 ml of buffer solution to prepare a dilution (1 / 10 dilution). Similarly, 1 / 100, 1 / 1000, and 1 / 10000 dilutions were prepared, except that the dilution ratio with the buffer solution was changed. Next, 0.050 ml of the 1 / 1 solution was taken and smeared on a stamp medium (Petan Check 25 PT1025, manufactured by Eiken Kasei Co., Ltd.). This procedure was repeated until the 1 / 1 solution was smeared. Two stamp media were prepared. A total of two stamp media were placed in an incubator (trade name: IS600; manufactured by Yamato Scientific Co., Ltd.) and cultured at 37°C for 24 hours. The number of colonies that appeared on each stamp medium for the 1 / 1 solution of sample No. 7-1 was counted, and the average value was calculated. Two smeared stamp plates were prepared for each of the 1 / 10, 1 / 100, 1 / 1000, and 1 / 10,000 diluted solutions in the same manner as above, and cultured. The number of colonies that appeared on each stamp plate for each dilution was then counted, and the average value was calculated. As a control, a 1 / 1 solution and 1 / 10 to 1 / 10000 dilutions of untreated sample No. 7-2 were prepared in the same manner as above, and stamp culture media were prepared and cultured in the same manner, and the average number of colonies was calculated. The results are shown in Table 6.

[0063] TIFF0007786801000006.tif41153

[0064] From the culture results of the 1 / 1000 diluted solution of sample No. 7-2, the number of bacteria present in 0.050 ml of the 1 / 1 solution of sample No. 7-2 was 5 x 10 3 = 5000 (CFU). In addition, the number of bacteria in 0.050 ml of the 1 / 1 solution for sample No. 7-1 after treatment was 0 (CFU). From this, it was found that the elimination rate of E. coli in the experiment using sample No. 7-1 was 99.98% ((5000-1 / 5000) x 100) or more. Here, the treatment of sample No. 7-1 with active oxygen was carried out on the surface of the filter paper opposite to the surface on which the bacterial solution was dropped. This shows that the sterilization treatment according to the present disclosure, which actively supplies active oxygen to the object to be treated, can sterilize not only the E. coli present on the surface of the filter paper, but also the E. coli present inside the filter paper. In this respect, the method according to the present disclosure is superior to sterilization treatments that use only UV light, which only sterilize the surface irradiated with UV light. [Explanation of symbols]

[0065] 101: Sterilization device, 102: Ultraviolet light source, 103: Plasma generator (plasma actuator), 104: Placement table, 105: Object to be treated, 105-1: Treatment surface of object to be treated, 109: Induced flow, 110: Placement table, 112: Sterilization container

Claims

1. A housing having at least one opening; a plasma generator disposed inside the housing; an ultraviolet light source disposed inside the housing; A sterilization device comprising: The plasma generating device comprises: a dielectric; a first electrode provided on a first surface of the dielectric; a second electrode provided on a second surface of the dielectric opposite to the first surface, and disposed diagonally opposite the first electrode across the dielectric; A plasma actuator comprising: The plasma actuator generates an induced flow containing ozone from an edge of the first electrode along an exposed portion of the first surface of the dielectric that is not covered by the first electrode by applying a voltage between the first electrode and the second electrode; the plasma actuator is disposed so that the induced flow flows out of the housing through the opening and is supplied to the surface of the object to be sterilized; the ultraviolet light source is disposed so as to be able to irradiate the surface, and irradiates the induced flow with ultraviolet light to generate active oxygen in the induced flow; A sterilization device characterized by:

2. The sterilization apparatus according to claim 1, wherein the peak wavelength of the ultraviolet light emitted by the ultraviolet light source is 220 nm to 310 nm.

3. The illuminance of the ultraviolet light from the ultraviolet light source at a position corresponding to the surface of the object to be treated is 100 μW / cm ２ The sterilization apparatus according to claim 1 or 2.

4. 4. The sterilization apparatus according to claim 1, wherein the plasma actuator generates an induced flow in which the ozone concentration measured at a position corresponding to the surface of the object to be treated is 20 ppm or more.

5. A sterilization method using the sterilization device according to any one of claims 1 to 4, A step of supplying an induced flow containing ozone generated by applying a voltage between the first electrode and the second electrode to a surface of an object to be sterilized; and irradiating the ozone-containing induced flow supplied to the surface of the workpiece with ultraviolet light from the ultraviolet light source; Including, A sterilization method characterized by:

6. The sterilization method according to claim 5, wherein the ultraviolet light has a peak wavelength of 220 nm to 310 nm.

7. The illuminance of the ultraviolet light on the surface of the object to be treated is 100 μW / cm ２ The sterilization method according to claim 5 or 6, wherein

8. The sterilization method according to any one of claims 5 to 7, wherein the ozone concentration measured on the surface of the object to be treated is 20 ppm or more.

9. A housing having at least one opening; a plasma generator disposed inside the housing; an ultraviolet light source disposed inside the housing; An active oxygen supplying device comprising: The plasma generating device comprises: a dielectric; a first electrode provided on a first surface of the dielectric; a second electrode provided on a second surface of the dielectric opposite to the first surface, and disposed diagonally opposite the first electrode across the dielectric; A plasma actuator comprising: The plasma actuator generates an induced flow containing ozone from an edge of the first electrode along an exposed portion of the first surface of the dielectric that is not covered by the first electrode by applying a voltage between the first electrode and the second electrode; the plasma actuator is disposed so that the induced flow flows out of the housing through the opening and is supplied to a surface of the workpiece; The ultraviolet light source irradiates the induced flow with ultraviolet light to generate active oxygen in the induced flow. An active oxygen supply device characterized by:

10. The active oxygen supplying device according to claim 9 , wherein the ultraviolet light source is disposed so as to be able to irradiate the object to be treated.

11. A housing having at least one opening; a plasma generator disposed inside the housing; an ultraviolet light source disposed inside the housing; An active oxygen treatment device comprising: The plasma generating device comprises: a dielectric; a first electrode provided on a first surface of the dielectric; a second electrode provided on a second surface of the dielectric opposite to the first surface, and disposed diagonally opposite the first electrode across the dielectric; A plasma actuator comprising: The plasma actuator is configured to apply a voltage between the first electrode and the second electrode, and the first surface of the dielectric is covered with the first electrode from the edge of the first electrode. creating an induced flow containing ozone along the exposed portion of the surface; the plasma actuator is disposed so that the induced flow flows out of the housing through the opening and is supplied to a surface of the workpiece; The ultraviolet light source irradiates the induced flow with ultraviolet light to generate active oxygen in the induced flow. A treatment device using active oxygen.

12. The treatment device using active oxygen according to claim 11 , wherein the ultraviolet light source is arranged so as to be able to irradiate the object to be treated.

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