Ultraviolet light irradiation device, method of using ultraviolet light irradiation device, and ultraviolet light irradiation method

Abstract

To provide an ultraviolet light irradiation device that can effectively inactivate microorganisms while ensuring safety for the human body, and to provide a method of using the ultraviolet light irradiation device.SOLUTION: An ultraviolet light irradiation device of the present invention comprises a light source that emits ultraviolet light with a main emission wavelength of 190 nm to 235 nm, a housing that houses the light source, an extraction part for extracting the ultraviolet light emitted from the light source to the outside of the housing, an optical filter that transmits ultraviolet light in a wavelength band of 190 nm to 235 nm and does not substantially transmit ultraviolet light in a wavelength band of 240 nm to 280 nm in the extraction part, and a diffusing member for diffusing the ultraviolet light, disposed on the ultraviolet light output side of the optical filter, in the extraction part.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an ultraviolet light irradiation device, a method for using an ultraviolet light irradiation device, and a method for irradiating ultraviolet light. [Background technology]

[0002] Microorganisms such as bacteria, fungi, and viruses are known to exhibit the highest absorption characteristics around a wavelength of 260 nm. Therefore, a technique for inactivating microorganisms by irradiating the surface of an object or space where the microorganisms exist with ultraviolet light that exhibits a high emission spectrum around a wavelength of 254 nm has been known.

[0003] For example, Patent Document 1 describes sterilizing a kitchen by installing a germicidal lamp that emits ultraviolet light in the kitchen, etc. Patent Document 2 describes sterilizing bacteria and viruses floating in the room by irradiating them with ultraviolet light.

[0004] In addition, the ultraviolet light irradiation devices described in Patent Documents 1 and 2 use ultraviolet light that is harmful to the human body, so measures are taken to prevent the ultraviolet light from being directed toward the human body, such as making the emitted ultraviolet light directional. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Utility Model Application Publication No. 63-187221 [Patent Document 2] Japanese Patent Application Publication No. 2017-018442 Summary of the Invention [Problem to be solved by the invention]

[0006] However, microorganisms such as bacteria, fungi, and viruses are particularly prevalent on the surfaces of the human body (for example, skin and hair), on the surfaces of objects that people frequently come into contact with (for example, furniture and office equipment), or in the air near the human body.

[0007] Due to the risk of irradiating the human body with ultraviolet light that is harmful to the human body, conventional ultraviolet light irradiation devices have been unable to irradiate ultraviolet light at critical locations where microorganisms need to be inactivated most, such as the surface of the human body, the surface of objects that people frequently come into contact with, and the space around the human body. Therefore, conventional ultraviolet light irradiation devices have had limitations in their ability to inactivate microorganisms.

[0008] The present invention provides an ultraviolet light irradiation device that can effectively inactivate microorganisms while ensuring safety for the human body, and a method for using the ultraviolet light irradiation device. [Means for solving the problem]

[0009] Not all wavelength bands of ultraviolet light are harmful to the human body. While UVC waves of 240 nm or more have been reported to be harmful to human cells, ultraviolet light with shorter wavelength bands has a lower penetrating power to human cells and is therefore significantly less harmful to the human body. Therefore, the present inventors focused on using ultraviolet light with a main emission wavelength of 190 nm to 235 nm in order to inactivate microorganisms while suppressing harmful effects to the human body.

[0010] The ultraviolet light irradiation device of the present invention comprises a light source that emits ultraviolet light of 190 nm to 235 nm; a housing that houses the light source; an extraction unit that extracts the ultraviolet light emitted from the light source to the outside of the housing; an optical filter that transmits ultraviolet light in a wavelength band of 190 nm to 235 nm and does not substantially transmit ultraviolet light in a wavelength band of 240 nm to 280 nm, in the extraction section; The extraction section includes a diffusing member that is disposed on the ultraviolet light emission side of the optical filter and that diffuses the ultraviolet light.

[0011] This ultraviolet light irradiation device suppresses ultraviolet light in the wavelength band above 240 nm, which is considered harmful to the human body, and therefore the distribution angle of the ultraviolet light can be expanded using a diffusing member. As a result, ultraviolet light can be irradiated evenly (with minimal unevenness) over a wide area to the location where microorganisms are to be inactivated (including the surface of the human body, the surface of objects frequently touched by people, spaces near the human body, and spaces where no people are present). This allows for effective inactivation of microorganisms while ensuring safety for the human body.

[0012] In this specification, microorganisms include all protists that have a cellular structure, such as bacteria, which are prokaryotes, and fungi, such as molds, which are eukaryotes, as well as viruses that do not have a cellular structure and have DNA or RNA nucleic acid as their genome.

[0013] As used herein, inactivation refers to either killing a protist by destroying its intracellular DNA, enzymes (proteins), or cell membrane, or eliminating the cell's proliferation function. In the case of a virus, inactivation refers to destroying its DNA or RNA, thereby eliminating its ability to infect cells. Viruses are contained in droplets or aerosols that are expelled from the mouth or nose of a person or animal when they exhale, spit, cough, or sneeze, and float in the air, adhering to objects such as furniture, floors, and walls, as well as to surfaces of the human body.

[0014] The ultraviolet light emitted by the light source may have a main emission wavelength of 190 nm to 235 nm. In this specification, the term "main emission wavelength" refers to a wavelength λi in a wavelength range Z(λi) that exhibits an integrated intensity of 40% or more of the total integrated intensity in the emission spectrum, when a wavelength range Z(λ) of ±10 nm from a certain wavelength λ is defined on the emission spectrum. For example, in a light source that has an extremely narrow half-width and exhibits light intensity only at a specific wavelength, such as an excimer lamp filled with a light-emitting gas containing KrCl, KrBr, or ArF, the wavelength with the highest relative illuminance (main peak wavelength) may usually be used as the main emission wavelength.

[0015] Furthermore, the ultraviolet light irradiation device further includes an optical filter that transmits ultraviolet light in the wavelength band of 190 nm or more and 235 nm or less, but does not substantially transmit ultraviolet light in the wavelength band of 240 nm to 280 nm. Therefore, by not transmitting ultraviolet light in the wavelength band of 240 nm to 280 nm, which may have an adverse effect on the human body, safety to the human body is improved. Furthermore, to further enhance safety for the human body, the optical filter may transmit ultraviolet light with a wavelength of 200 nm or more and 230 nm or less, and substantially block ultraviolet light with a wavelength of 230 nm to 280 nm.

[0016] The diffusing member may be disposed in contact with the optical filter. As will be described in detail later, this arrangement suppresses return light from the diffusing member to the interior of the housing, improving light irradiation efficiency. Furthermore, it is easy to support a thin diffusing member.

[0017] The diffusion member may be a diffusion sheet.

[0018] The diffusion sheet may be mainly composed of PTFE.

[0019] A fixing portion for fixing the diffusion sheet around the extraction portion may be provided, or a fixing portion for clamping the outer periphery of the diffusion sheet to fix the position may be provided.

[0020] The diffusing member may be a diffusing film formed on the optical filter.

[0021] The diffusion film may be mainly composed of silica or alumina.

[0022] The diffusing member may be disposed between the optical filter and a transmission plate that transmits the ultraviolet light.

[0023] The thickness of the diffusing member may be less than 1 mm.

[0024] The thickness of the diffusing member may be less than 0.5 mm.

[0025] The light source may be an excimer lamp.

[0026] A method of using the ultraviolet light irradiation device of the present invention includes arranging the ultraviolet light irradiation device so that at least a portion of the emitted ultraviolet light is irradiated toward a space occupied by an individual, and causing the ultraviolet light irradiation device to radiate the ultraviolet light.

[0027] The ultraviolet light irradiation device of the present invention comprises: a light source that emits ultraviolet light having a main emission wavelength of 190 nm to 235 nm; a housing that houses the light source; an extraction unit that extracts the ultraviolet light emitted from the light source to the outside of the housing; The extraction unit is provided with an optical filter that transmits ultraviolet light in a wavelength band of 190 nm to 235 nm and does not substantially transmit ultraviolet light in a wavelength band of 240 nm to 280 nm, The housing has an attachment portion at the extraction portion for attaching a diffusing member that diffuses the ultraviolet light to the ultraviolet light emission side of the optical filter.

[0028] The ultraviolet light irradiation method of the present invention comprises: UV light is emitted from a light source that emits UV light of 190 nm to 235 nm, an optical filter that transmits ultraviolet light in a wavelength band of 190 nm to 235 nm and does not substantially transmit ultraviolet light in a wavelength band of 240 nm to 280 nm, and selectively transmits the ultraviolet light emitted from the light source; A diffusing member disposed on the exit side of the optical filter diffuses the light emitted from the optical filter. [Effects of the Invention]

[0029] It is possible to provide an ultraviolet light irradiation device that can effectively inactivate microorganisms, and a method for using the ultraviolet light irradiation device. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1 is a perspective view schematically illustrating the appearance of an ultraviolet light irradiation device. [Figure 2] FIG. 1 is a perspective view schematically illustrating the appearance of an ultraviolet light irradiation device. [Figure 3] FIG. 2 is a perspective view showing only a light source and an electrode block taken out from the ultraviolet light irradiation device. [Figure 4] FIG. 2 is a cross-sectional schematic diagram of the ultraviolet light irradiation device in the XZ plane. [Figure 5] 10A and 10B are diagrams illustrating the effect of a diffusing member in increasing the light distribution angle of emitted light. [Figure 6] 1 is an example of an emission spectrum of an excimer lamp containing KrCl in the light emitting gas. [Figure 7] 1 is a graph showing an example of a transmission spectrum of an optical filter. [Figure 8] 1 is a schematic diagram for explaining the angle of incidence of ultraviolet light on an optical filter. [Figure 9] FIG. 5 is an enlarged view of the P1 region in FIG. [Figure 10A] 1 is a perspective view schematically illustrating the appearance of an ultraviolet light irradiation device having a diffusing member according to a first example. [Figure 10B] FIG. 10B is a cross-sectional view of the ultraviolet light irradiation device of FIG. 10A. [Figure 11] 10A and 10B are diagrams showing modified examples of fixing portions that fix the diffusion member. [Figure 12A] FIG. 10 is a cross-sectional view of an ultraviolet light irradiation device having a second example of a diffusing member. [Figure 12B] FIG. 1 is a cross-sectional schematic diagram of an ultraviolet light irradiation device having a diffusion film formed on an optical filter. [Figure 13] FIG. 10 is a diagram illustrating a second embodiment of the ultraviolet light irradiation device. [Figure 14] FIG. 1 is a cross-sectional schematic view of an ultraviolet light irradiation device equipped with an optical lens. [Figure 15] FIG. 1 is a cross-sectional view of an ultraviolet light irradiation device equipped with a reflecting section. [Figure 16] FIG. 10 is a diagram schematically illustrating a measurement facility for measuring the effect of a diffusion member. [Figure 17] 10 is a graph showing relative illuminance versus change in rotation angle. [Figure 18]This is a graph in which the horizontal axis represents the thickness of the PTFE sheet and the vertical axis represents the relative illuminance. DETAILED DESCRIPTION OF THE INVENTION

[0031] Each embodiment of the ultraviolet light irradiation device will be described with reference to the drawings. Note that the following drawings are schematic illustrations, and the dimensional ratios in the drawings do not necessarily correspond to the actual dimensional ratios, and the dimensional ratios between the drawings do not necessarily correspond to the actual dimensional ratios.

[0032] In the following, each drawing will be described with reference to the XYZ coordinate system as appropriate. In the XYZ coordinate system, the direction in which a ray on the optical axis of emitted ultraviolet light travels is defined as the +X direction, and the plane perpendicular to the X direction is defined as the YZ plane. In this specification, when a direction is expressed and a positive or negative direction is distinguished, it is described with a positive or negative sign, such as "+X direction" or "-X direction." When a direction is expressed without distinguishing between positive and negative directions, it is simply described as "X direction." In other words, in this specification, when simply referring to the "X direction," it includes both the "+X direction" and the "-X direction." The same applies to the Y direction and the Z direction.

[0033] First Embodiment [Outline of UV light irradiation equipment] A first embodiment of the ultraviolet light irradiation device of the present invention will be described with reference to Figures 1, 2, and 3. Figures 1 and 2 are perspective views schematically showing the appearance of the ultraviolet light irradiation device. Figure 3 is a view showing only the light source and electrode block extracted from the ultraviolet light irradiation device.

[0034] The ultraviolet light irradiation device 10 of this embodiment includes an excimer lamp 3 (see FIG. 2 or 3) that emits ultraviolet light, a housing 2 that houses the excimer lamp 3, an extraction unit 4 that extracts the ultraviolet light emitted from the excimer lamp 3 to the outside of the housing 2 in the +X direction, a diffusion member 5 that diffuses the ultraviolet light, and an optical filter 6, which will be described later. In FIGS. 1 and 2, arrow L1 indicates the optical axis of the ultraviolet light emitted from the excimer lamp 3 and the traveling direction of the light ray on the optical axis.

[0035] In this embodiment, the housing 2 is composed of a first frame 2a having an opening in the center that serves as the extraction portion 4, and a second frame 2b that does not have an opening, and the second frame 2b and the first frame 2a are fitted together to form an internal space surrounded by the housing 2. In this internal space, an excimer lamp 3 and two electrode blocks (9a, 9b) that supply power to the excimer lamp 3 are arranged.

[0036] The two electrode blocks (9a, 9b) are fixed to the surface of the second frame 2b that contacts the internal space (see Figures 2 and 3). Two connection terminals (8a, 8b) are provided on the surface that contacts the outside of the second frame 2b. The two connection terminals (8a, 8b) are electrically connected to the electrode blocks (9a, 9b) across the second frame 2b. Power supply lines (7a, 7b) that supply power from an external power source (not shown) are connected to the two connection terminals (8a, 8b), respectively. The two electrode blocks (9a, 9b) are made of a conductive material (e.g., Al, Al alloy, stainless steel, etc.).

[0037] [light source] One embodiment of the excimer lamp 3 will be described with reference to Figure 3. In this embodiment, the excimer lamp 3 includes three excimer lamps 3 (3a, 3b, 3c) spaced apart in the Z direction. Two electrode blocks (9a, 9b) contact the outer surface of the arc tube of each excimer lamp 3 (3a, 3b, 3c). This allows power to be supplied to the excimer lamps 3, which then light up.

[0038] In this embodiment, a KrCl excimer lamp in which a light-emitting gas containing KrCl is sealed inside the arc tube is used as the excimer lamp 3. Therefore, the excimer lamp 3 emits ultraviolet light with a main peak wavelength of 190 nm to 235 nm. In particular, the KrCl excimer lamp emits ultraviolet light with a main peak wavelength of around 222 nm.

[0039] The excimer lamp 3 is not limited to a KrCl excimer lamp. For example, a KrBr excimer lamp, in which a light-emitting gas containing KrBr is sealed inside the arc tube, may be used. A KrBr excimer lamp emits ultraviolet light with a main peak wavelength of around 207 nm.

[0040] The arc tube of the excimer lamp 3 (3a, 3b, 3c) preferably has a length in the tube axis direction (Y direction) of 15 mm to 200 mm, and an outer diameter of 2 mm to 16 mm.

[0041] [Overview of Diffusion Materials] 4 is a cross-sectional schematic diagram of the ultraviolet light irradiation device 10 in the XZ plane. In the ultraviolet light irradiation device 10 of this embodiment, a diffusing member 5 that diffuses ultraviolet light and an optical filter 6 are disposed in an opening that constitutes the extraction unit 4. Note that "disposed in the extraction unit" includes a case where the diffusing member 5 or the optical filter 6 is disposed completely integrated with the light extraction surface, as well as a case where the diffusing member 5 or the optical filter 6 is disposed at a position spaced a very small distance (for example, several mm to several tens of mm) in the X direction from the light extraction surface.

[0042] The light emitted from the excimer lamps 3 (3a, 3b, 3c) is blocked in a specific wavelength band by the optical filter 6. The details of the optical filter 6 will be described later. The light beam F1 emitted from the optical filter 6 is diffused by the diffusing member 5, and the angle at which the light spreads, i.e., the light distribution angle, becomes larger.

[0043] With reference to FIG. 5, the expansion of the light distribution angle of the emitted light, which is the effect of the diffusing member 5, will be described. In FIG. 5, if a diffusing member is not included, a light beam F2 of ultraviolet light is emitted from the ultraviolet light irradiation device 10 at a light distribution angle θ2 centered on the optical axis (arrow L1). If a diffusing member 5 is included, a light beam F1 of ultraviolet light is emitted at a light distribution angle θ1. The light distribution angle θ1 when the diffusing member 5 is included is larger than the light distribution angle θ2 when the diffusing member is not included. The light distribution angle (θ1, θ2) is defined as the angle between the outermost opposing light beams of the light beam (F1, F2) that spreads around the optical axis. The light beam (F1, F2) is defined as a beam of light that spreads around the optical axis, which is the center, and has a brightness equal to or greater than half the brightness of the light beam on the optical axis L1.

[0044] The ultraviolet light irradiation device 10 can irradiate ultraviolet light over a wide range by expanding the orientation angle of the emitted light using the diffusing member 5. This makes it possible to cover the area where microorganisms are to be inactivated with a small number of ultraviolet light irradiation devices, which is highly cost-effective.

[0045] Next, we will explain another function of the diffusing member 5, which is the suppression of unevenness in the emitted light. When there is no unevenness (or when there is little unevenness), the area receiving locally weak light is reduced, and therefore the area with a low inactivation effect is reduced. Furthermore, since the area receiving locally strong light is reduced, a higher level of safety is ensured while the upper limit of the irradiation amount of ultraviolet light is less likely to be imposed. This will be described in detail below.

[0046] There are cases where it is required to limit the amount of ultraviolet light irradiated to the environment, including humans. For example, ACGIH (American Conference of Governmental Industrial Hygienists) and JIS Z 8812 (Method of measuring harmful ultraviolet radiation) specify that the amount of ultraviolet light irradiated to the human body per day (8 hours) must be below the threshold limit value (TLV) for each wavelength.

[0047] As mentioned above, the wavelength of the emitted light used in the present invention is a wavelength that is extremely low in harmfulness to the human body, but in order to further increase safety, it is desirable to set the irradiation amount of ultraviolet light so as to satisfy the above-mentioned TLV regulations.

[0048] Large unevenness in the emitted light indicates a large difference in intensity between areas receiving locally strong light and areas receiving locally weak light. When setting the UV light irradiation dose to satisfy the above-mentioned TLV regulations, it is desirable to set the upper limit of the irradiation dose to match the area receiving locally strong light. This makes it more susceptible to the constraints of the upper limit of the UV light irradiation dose, and in particular, the UV light irradiation dose for areas receiving locally weak light will be restricted more than necessary.

[0049] Conversely, when the unevenness of the emitted light is reduced, the difference in light intensity between regions is also reduced, making it less susceptible to the upper limit of the ultraviolet light irradiation amount. Therefore, by suppressing unevenness of the emitted light with the diffusing member 5, the ultraviolet light irradiation device 10 ensures a higher level of safety while also being less susceptible to the upper limit of the ultraviolet light irradiation amount.

[0050] To ensure a higher level of safety, the local maximum irradiance of the ultraviolet light (the irradiance in the local area where the most intense light is irradiated) may be suppressed by the diffusing member 5. For example, the local maximum irradiance of the ultraviolet light on the light emitting surface of the diffusing member 5 may be suppressed to 3 mW / cm. 2 Below that, 1mW / cm 2 The material, thickness, shape, etc. of the diffusing member may be selected or adjusted so as to suppress the following.

[0051] From the viewpoint of inactivating microorganisms by irradiation with ultraviolet light, a material that is transparent to ultraviolet light with a wavelength of 190 nm to 235 nm is used as the diffusing member 5. The diffusing member 5 may be a material that suppresses the transmission of ultraviolet light with wavelengths other than 190 nm to 235 nm.

[0052] The diffusing member 5 may have a diffusing effect not only on ultraviolet light but also on visible light. The ultraviolet light irradiation device 10 described in the present invention is expected to be applied to a variety of locations and facilities. If the excimer lamp 3, electrode block, etc. inside the ultraviolet light irradiation device 10 were clearly identifiable, it could spoil the surrounding scenery and the appearance of the facility. However, by placing a diffusing member that has a diffusing effect on visible light in the extraction section 4, it is possible to make the excimer lamp 3 inside the ultraviolet light irradiation device 10 invisible or not clearly visible, thereby enabling inactivation of microorganisms while blending in with the surrounding scenery and the appearance of the facility.

[0053] The outline of the diffusing member has been described above, and specific examples of the diffusing member will be described later.

[0054] [Optical filter] The optical filter 6 functions as a bandpass filter that blocks, i.e., substantially blocks, ultraviolet light in a specific wavelength band. For example, in the case of a KrCl excimer lamp, as shown in FIG. 6 , the spectrum of the emitted ultraviolet light has a light output concentrated almost entirely around the main peak wavelength of 222 nm, while a small amount of light output is also observed for ultraviolet light in the wavelength band of 240 nm or more and 280 nm or less, which may be harmful to the human body. In this embodiment, the optical filter 6 is provided in the region that constitutes the extraction section 4, thereby substantially blocking the transmission of ultraviolet light in the wavelength band of 240 nm or more and 280 nm or less. This reliably prevents ultraviolet light in the wavelength band that may be harmful to the human body from leaking out of the housing, further improving the safety of the light irradiation device to the human body.

[0055] The optical filter 6 is not limited in its location or form as long as it functions as a bandpass filter that blocks ultraviolet light in a specific wavelength band. For example, it may be formed so as to be in contact with the light source or may be formed at a distance from the light source.

[0056] In this specification, "not substantially transmitting ultraviolet light" means that the ultraviolet light intensity is suppressed to at least 5% or less of the ultraviolet light intensity at the peak wavelength in a specific wavelength band in the direction of the principal beam. In the present invention, by using an optical filter, the intensity of ultraviolet light between 240 nm and 300 nm is blocked to 5% or less of the peak wavelength intensity. Note that, for light in the wavelength band that the optical filter is intended to block, it is preferable that the intensity of ultraviolet light transmitted through the optical filter is suppressed to 2% or less of the peak wavelength intensity. It is even more preferable that the intensity of ultraviolet light transmitted through the optical filter is suppressed to 1% or less of the peak wavelength intensity.

[0057] The optical filter 6 may be configured to include multiple dielectric multilayer films with different refractive indices. Examples of dielectric multilayer films include those in which HfO2 layers and SiO2 layers are alternately stacked, and those in which SiO2 layers and Al2O3 layers are alternately stacked. A dielectric multilayer film in which HfO2 layers and SiO2 layers are alternately stacked can reduce the number of layers to obtain the same wavelength selection characteristics compared to a dielectric multilayer film in which SiO2 layers and Al2O3 layers are alternately stacked, and therefore can increase the transmittance of selected ultraviolet light.

[0058] As described above, the optical filter 6 may be composed of multiple dielectric multilayer films with different refractive indices, but the transmittance of the optical filter 6 composed of dielectric multilayer films inevitably changes depending on the angle of incidence of ultraviolet light.

[0059] FIG. 7 is a graph showing an example of the transmission spectrum of the optical filter 6 for each angle of incidence when ultraviolet light is incident on the optical filter 6. In this example graph, the optical filter 6 is designed assuming that the light-emitting gas of the excimer lamp 3 contains KrCl, i.e., that the excimer lamp 3 emits ultraviolet light with a main peak wavelength of 222 nm. Each curve in the graph is obtained by plotting the ratio of the intensity of light incident on the optical filter 6 to the intensity of light emitted from the optical filter 6, for different wavelengths. The angle of incidence is defined as the angle θ3 between the normal 6N to the incident surface of the optical filter 6 and the ultraviolet light L2 incident on the incident surface of the optical filter 6, as shown in FIG.

[0060] From the graph in Figure 7, it can be seen that the optical filter 6 easily transmits light components with a small angle of incidence (angle θ3), but does not easily transmit light components with a large angle of incidence. Light components with a large angle of incidence are reflected without entering the optical filter 6. As a result, the light emitted from the optical filter 6 has a higher proportion of light components with a small angle of incidence compared to the light incident on the optical filter 6, and the light distribution angle is smaller. In other words, the optical filter 6 reduces the light distribution angle of light.

[0061] For these reasons, the above-described diffusing member 5 has a particularly significant effect when using the optical filter 6 that reduces the light distribution angle. In other words, even when the light distribution angle is reduced by using the optical filter 6, the ultraviolet light irradiation device 10 can obtain a large light distribution angle by arranging the diffusing member 5 after the optical filter 6 (i.e., arranging the optical filter 6 between the excimer lamp 3 and the diffusing member 5).

[0062] An additional effect of using the diffusing member 5 in combination with the optical filter 6 is the reflection of light returned by the diffusing member 5 in the optical filter 6. This will be explained with reference to Figure 9, which is an enlarged view of area P1 in Figure 4. Looking microscopically at the diffusion effect of light L4 incident on point P2 of the diffusing member 5, light L4 is diffused in various directions at point P2.

[0063] Light FL that is refracted at point P2 and travels in the +X direction is emitted from the ultraviolet light irradiation device 10, whereas light (B0, B1) that is diffused at point P2 and travels in the -X direction becomes returning light that attempts to return inside the housing of the ultraviolet light irradiation device 10.

[0064] However, as described above, the optical filter 6 has the property of easily transmitting light components with small angles of incidence, while reflecting light components with large angles of incidence. Therefore, of the light returning from point P2, most of the light B1 has a large angle of incidence with respect to the optical filter 6 and is converted into light traveling in the +X direction. The only light returning to the inside of the housing is a small amount of light B0, which has a small angle of incidence with respect to the optical filter 6. Therefore, the amount of light returning to the inside of the housing is suppressed, and the light output efficiency is improved.

[0065] As described above, the diffusing member 5 is provided to obtain the effect of widening the light distribution angle of the optical filter 6 arranged for wavelength selection, but looking at the optical filter 6, it also has the effect of suppressing the return light generated by providing the diffusing member 5. When the diffusing member 5 and the optical filter 6 are used in combination, these two different effects can be obtained simultaneously.

[0066] When the diffusing member 5 is disposed in contact with the optical filter 6, the angle of incidence of the returning light from the diffusing member 5 to the optical filter 6 can be made larger than when the diffusing member 5 is disposed away from the optical filter 6. Therefore, by disposing the diffusing member 5 in contact with the optical filter 6, the returning light is suppressed and the light output efficiency is further improved.

[0067] [Examples of diffusion materials] A first example of the diffusing member 5 will be described with reference to Figures 10A and 10B. Figure 10A is a perspective view schematically showing the appearance of an ultraviolet light irradiation device 10, and Figure 10B is a cross-sectional schematic view of the ultraviolet light irradiation device 10 in the XZ plane. In the ultraviolet light irradiation device 10, the diffusing member 5 is configured to include a diffusion sheet 5s. The ultraviolet light irradiation device 10 has a fixing portion 13 that fixes the diffusion sheet 5s.

[0068] In this embodiment, the diffusion sheet 5s is a diffusion sheet whose main component is PTFE (polytetrafluoroethylene) (hereinafter, sometimes referred to as a "PTFE sheet"). PTFE is suitable as a diffusion member because its molecular structure itself exhibits crystallinity that exhibits light diffusibility. The "main component" refers to the component that is most abundant in the diffusion sheet. The main component may account for 90% by mass or more of the diffusion sheet, or may account for 95% by mass or more of the diffusion sheet.

[0069] PTFE sheet manufacturing methods include sintering PTFE microparticles into a sheet, and stretching a base material containing compressed PTFE microparticles into a sheet. In particular, when PTFE sheets are manufactured by sintering PTFE microparticles into a sheet, they exhibit a porous structure with many gaps between the microparticles, which diffuses a particularly large amount of light, resulting in particularly excellent light diffusion properties. Furthermore, when PTFE microparticles are sintered into a sheet, the crystallinity of the PTFE varies depending on the sintering temperature. A higher sintering temperature increases the crystallinity of the PTFE sheet, further enhancing its diffusivity.

[0070] As a material for the diffusion sheet other than PTFE, other fluorine-based resins such as PFA or PVDF, or materials mainly composed of resins such as polycarbonate, polyethylene, PET, etc. The thickness of the diffusion sheet is preferably less than 1 mm, and more preferably less than 0.5 mm.

[0071] The fixing portion 13 has a frame shape that surrounds the extraction portion 4. The diffusion sheet 5s is sandwiched and fixed between the optical filter 6 and the fixing portion 13. The optical filter 6 is supported in the X direction by a protrusion 25 that protrudes from the inner wall surface of the first frame 2a. When the diffusion sheet 5s is fixed in this manner, the diffusion sheet 5s is disposed in contact with the optical filter 6, and the diffusion sheet 5s can be easily supported even if it is thin. The frame-shaped fixing portion 13 may be made of an ultraviolet light-transmitting material or an ultraviolet light-non-transmitting material (e.g., metal, resin, etc.).

[0072] Adhesive may be used to secure the diffusion sheet 5s. However, if adhesive is used in a position exposed to ultraviolet light, the ultraviolet light may cause the adhesive to deteriorate. This problem does not occur if the diffusion sheet 5s is sandwiched and secured using the securing portion 13 without using adhesive.

[0073] FIG. 11 shows a modified example of a fixing portion for fixing the diffusing member. The fixing portion 23 shown in FIG. 11 is a transmissive plate that transmits ultraviolet light. The diffusion sheet 5s is fixed by being sandwiched between the fixing portion 23, which is a transmissive plate, and the optical filter 6. The transmissive plate may be made of, for example, quartz glass. As a further modified example, the diffusion sheet 5s may be fixed using a mesh member that covers the diffusion sheet 5s. The mesh member may be made of a material that is not transmissive to ultraviolet light (for example, metal or resin). In FIG. 11, the fixing portion 23 is provided so as to cover the extraction portion 4.

[0074] A second example of the diffusing member 5 will be described with reference to FIG. 12A. For the sake of explanation, FIG. 12A shows the ultraviolet light irradiation device 10 separated into the housing 2 and the diffusing member 5. In reality, however, the diffusing member 5 is disposed in contact with or near the housing 2a. The ultraviolet light irradiation device 10 has a diffusing member 5 including a diffusing film 5b. In FIG. 12A, the diffusing film 5b is formed on one main surface of a quartz glass substrate 15. The ultraviolet light irradiation device 10 is configured such that the quartz glass substrate 15, on which the diffusing film 5b is formed, is attached to the housing 2. When the quartz glass substrate 15 is attached to the housing 2, the diffusing film 5b and the optical filter 6 may be spaced apart or may be in contact with each other.

[0075] The diffusion film 5b is made of a material containing, for example, silica or alumina as a main component, and the thickness of the diffusion film is preferably less than 1 mm, and more preferably less than 0.5 mm.

[0076] An example of a method for forming the diffusion film 5b will be described using a silica diffusion film as an example. Crushed silica powder that has been heated and melted in the atmosphere is sprayed onto the surface of the quartz glass 15 (thermal spraying method). The crushed silica powder is, for example, approximately spherical fine particles with a particle size of 100 nm to 100 μm. A bonding agent for bonding the fine particles may be sprayed together with the fine particles. Other film formation methods, such as spray coating without heating, dip coating, or spin coating, may also be used.

[0077] 12B shows a modified example of the diffusing member 5 including a diffusing film 5b. In this modified example, the diffusing film 5b is formed directly on the optical filter 6.

[0078] [How to use] In one embodiment of the ultraviolet light irradiation device according to the present invention, the ultraviolet light irradiation device is disposed so that the emitted ultraviolet light is directed toward a manned space, and the ultraviolet light irradiation device can be used to irradiate the ultraviolet light. A manned space refers to a space that a person can enter, regardless of whether or not a person is actually present. Examples of manned spaces include spaces inside buildings such as homes, offices, schools, hospitals, and theaters, as well as spaces inside vehicles such as automobiles, buses, trains, and airplanes. The ultraviolet light irradiation device 10 is disposed on a ceiling, wall, pillar, or floor facing the manned space, with the output unit 4 facing the manned space. The ultraviolet light irradiation device 10 is then turned on to irradiate ultraviolet light toward the manned space.

[0079] This method of use eliminates the need to irradiate ultraviolet light while avoiding the human body, as was the case in the past, and allows for even (with minimal unevenness) irradiation of ultraviolet light to the entire occupied space, including the surface of the human body (skin, etc.), the surface of objects that people frequently come into contact with, and the space near the human body, which are the most important areas where microorganisms need to be inactivated. Therefore, microorganisms can be inactivated effectively.

[0080] The ultraviolet light irradiation device may be built into lighting equipment such as a fluorescent lamp or an LED. When built into lighting equipment, the diffusing member used in the ultraviolet light irradiation device may also be used as a diffusing member for visible light used in the lighting equipment.

[0081] Second Embodiment A second embodiment of an ultraviolet light irradiation device of the present invention will be described with reference to Figure 13. Matters other than those described below can be implemented in the same manner as in the first embodiment. An ultraviolet light irradiation device 60 of the second embodiment includes excimer lamps 3 (3a, 3b, 3c), a housing 2, an extraction unit 4 that extracts ultraviolet light emitted from the excimer lamps 3 to the outside of the housing 2, and an optical filter 6 in the extraction unit 4 that transmits ultraviolet light in the wavelength band of 190 nm to 235 nm and substantially does not transmit ultraviolet light in the wavelength band of 240 nm to 280 nm or less.

[0082] The ultraviolet light irradiation device 60 of this embodiment does not include a diffusing member 5. The housing 2 has an attachment portion 51 for attaching the diffusing member 5 so that the diffusing member 5 can be later attached to the ultraviolet light irradiation device 60. In this embodiment, the attachment portion 51 is a screw hole, and the diffusing member 5 is attached to the ultraviolet light irradiation device 60 by sandwiching the diffusing member 5 and fitting screws 52 into the screw holes. This embodiment of the attachment portion 51 for the diffusing member 5 is one example, and various other embodiments such as hooks or hook-and-loop fasteners can also be applied. By attaching the diffusing member 5 later, it is possible to replace only the diffusing member 5 when it deteriorates.

[0083] The above describes embodiments of the ultraviolet light irradiation device and the method of using the ultraviolet light irradiation device, but the present invention is not limited to the above-mentioned embodiments, and various changes and improvements can be made to the above-mentioned embodiments within the scope of the invention.

[0084] For example, although an example has been described in which the excimer lamp 3 is used as the light source, a solid-state light source configured by an LD or an LED may also be used as the light source.

[0085] For example, a light source that emits ultraviolet light with a main emission wavelength of 190 nm to 230 nm may be used. Ultraviolet light with a main emission wavelength upper limit of 230 nm is safer for the human body than ultraviolet light with a main emission wavelength upper limit of 235 nm.

[0086] For example, a light source that emits ultraviolet light with a main emission wavelength of 200 nm to 230 nm may be used. Ultraviolet light with a main emission wavelength lower limit of 200 nm has a lower ability to decompose oxygen in the atmosphere and generate ozone than ultraviolet light with a main emission wavelength lower limit of 190 nm. Gases with high ozone concentrations are harmful to the human body, so suppressing the generation of ozone further enhances safety for the human body. Furthermore, the wavelength band described above does not necessarily have to be the main emission wavelength.

[0087] For example, an optical filter that transmits ultraviolet light in the wavelength range of 200 nm to 230 nm and substantially blocks ultraviolet light in the wavelength range of 240 nm to 280 nm as well as ultraviolet light in the wavelength range below 200 nm may be used. By substantially blocking the transmission of ultraviolet light in the wavelength range below 200 nm, ozone generation is suppressed, further increasing safety for the human body.

[0088] For example, a reflective member that reflects the light emitted by the light source may be disposed inside the housing 2. By disposing the reflective member, the amount of light that travels from the light source toward the inner wall of the housing 2 is reduced, and the amount of light that travels toward the extraction unit 4 is increased, thereby increasing the illuminance of the light emitted from the ultraviolet light irradiation device 10.

[0089] The diffusion member 5 or the optical filter 6 may be disposed not only at the opening of the housing 2 that constitutes the extraction portion 4 but also outside the housing 2.

[0090] [Improved light output efficiency] An example of an improvement to the above embodiment is an improvement in light output efficiency. For example, as an example of a reflective member, a film of a material that reflects ultraviolet light may be formed on the electrode blocks (9a, 9b), or the electrode blocks (9a, 9b) themselves may be made of a material that reflects ultraviolet light. If the surfaces of the electrode blocks (9a, 9b) are reflective, the electrode blocks (9a, 9b) also function as reflective sections that direct ultraviolet light toward the extraction section 4. Furthermore, as will be described in detail later, a reflective section separate from the electrode blocks (9a, 9b) may be provided to direct more light toward the extraction section 4.

[0091] As mentioned above, the optical filter 6 may be composed of multiple dielectric multilayer films with different refractive indices. However, the transmittance and reflectance of an optical filter 6 composed of a dielectric multilayer film change depending on the angle of incidence of ultraviolet light. For example, as shown in the graph in Figure 7, it can be seen that the optical filter 6 easily transmits light components with small angles of incidence, while it is difficult to transmit light components with large angles of incidence. The angle of incidence here is defined as the angle θ3 between the normal 6N to the incident surface of the optical filter 6 and the ultraviolet light L2 incident on the incident surface of the optical filter 6, as shown in Figure 8.

[0092] For these reasons, when ultraviolet light is incident on the optical filter 6 at a relatively large angle of incidence (for example, 30° or more), the transmittance of the optical filter 6 deteriorates, and the light emission efficiency from the optical filter 6 decreases to a certain extent. In addition, part of the light reflected by the optical filter 6 may be irradiated onto the housing (casing) 2, which may cause deterioration of the housing 2. For this reason, it is desirable to control the ultraviolet light emitted from the light source so that the angle of incidence when it is incident on the optical filter 6 is small. This is particularly desirable when the light source and the optical filter 6 are arranged at a distance from each other.

[0093] Therefore, it is desirable that the ultraviolet light irradiation device include an optical element that increases the directivity of ultraviolet light emitted from the light source and increases the light components with a small angle of incidence on the optical filter 6. This reduces the light components with a large angle of incidence on the optical filter 6 and increases the light components with a small angle of incidence, thereby increasing the light emission efficiency from the optical filter 6. The above-mentioned optical element can be an optical lens, an optical film, a reflector, or the like that can increase the directivity of ultraviolet light emitted from the light source and control the angle of incidence on the optical filter 6 to be small.

[0094] [Optical elements] One embodiment of the optical element will be described with reference to Fig. 14. Fig. 14 shows a cross-sectional schematic diagram of an ultraviolet light irradiation device 70 in which an optical lens 11a is used as the optical element 11. The optical lens 11a is a condenser lens that reduces the divergence angle of the ultraviolet light emitted from the light source. The condenser lens reduces the divergence angle of the ultraviolet light, making it easier for the ultraviolet light to enter the optical filter.

[0095] The optical lens 11a is disposed between the light source (here, the excimer lamp 3) and the optical filter 6. The shape of the optical lens 11a is not particularly limited as long as it reduces the divergence angle of the ultraviolet light emitted from the light source. Furthermore, while FIG. 14 shows that the incident angle appearing in a cross section along the XZ plane is controlled to be small, the incident angle appearing in a cross section along the XY plane may also be controlled to be small. Furthermore, the incident angles appearing in both a cross section along the XZ plane and a cross section along the XY plane may also be controlled to be small.

[0096] Another embodiment of the optical element will be described with reference to Fig. 15. Fig. 15 shows a cross-sectional schematic diagram of an ultraviolet light irradiation device 80 in which a reflector 11b is used as the optical element 11. In the ultraviolet light irradiation device 80, a reflector 11b is provided as the optical element 7 in the vicinity of at least one of the electrode blocks (9a, 9b). Fig. 15 shows an example in which the reflector 11b is provided in the electrode block 9b.

[0097] The reflecting portion 11b may have a flat or curved reflecting surface 11b1 that is inclined toward the extraction portion 4 where the optical filter 6 is provided. The reflecting surface 11b1 has a shape in which the opening width increases toward the optical filter 6. In FIG. 15, the reflecting portion 11b is provided with a tapered reflecting portion 11b that tapers toward the optical filter 6, and the reflecting surface 11b1 is provided on the tapered side surface. The reflecting surface 11b1 is curved, but may also be formed in a flat shape.

[0098] The reflecting portion 11b has a flat or curved reflecting surface 11b1 inclined relative to the light extraction surface, so that a portion of the ultraviolet light irradiated from the light source (here, the excimer lamp 3) is reflected by the reflecting surface 11b1 and its traveling direction is changed. Specifically, among the ultraviolet light emitted from the light source with a predetermined divergence angle, the ultraviolet light traveling with a large divergence angle is reflected by the reflecting surface 11b1 and its traveling direction is changed. Because the reflecting surface 11b1 is configured as a flat or curved surface inclined relative to the optical filter 6, the angle of incidence when the light is reflected by the reflecting surface 11b1 and incident on the optical filter is reduced. This reduces the light components with large angles of incidence on the optical filter 6 and increases the light components with small angles of incidence, thereby improving the light output efficiency from the optical filter 6. In particular, by making the reflecting surface 11b1 a parabolic curved surface, the divergence angle from the light source can be more directional, thereby improving the light output efficiency of the optical filter 6.

[0099] 15, the reflector 11b is configured as a separate body from the electrode block, but the reflector 11b and the electrode block may be formed integrally. In this case, the reflector 11b is formed in at least one of the electrode blocks (9a, 9b).

[0100] The electrode blocks (9a, 9b) and the reflector 11b are preferably made of a material (e.g., Al, Al alloy, stainless steel, etc.) that is reflective to ultraviolet light in the 190 nm to 235 nm wavelength range. This allows the electrode blocks (9a, 9b) and the reflector 11b to reflect ultraviolet light emitted from the light source (here, the excimer lamp 3), improving light emission efficiency. For example, each electrode block (9a, 9b) may have a shape in which a curved first surface that contacts the outer surface of the arc tube of the respective excimer lamp 3 (3a, 3b, 3c) is connected to a curved second surface that is inclined relative to the light extraction surface, and the ultraviolet light emitted from the excimer lamp 3 is reflected by the first and second surfaces. That is, power is supplied from the first surface that contacts the outer surface of the arc tube, and ultraviolet light is reflected by the first and second surfaces, increasing the light component with a small angle of incidence on the optical filter 6. The first and second surfaces are each made of a different curved shape.

[0101] 14 and 15 show an optical element 11 provided inside the housing 2. Ultraviolet light emitted from the light source is incident on the optical filter 6 via the optical element 11, and the light component of the ultraviolet light having a small angle of incidence with respect to the optical filter 6 is increased.

[0102] 14 and 15 do not show a diffusing member, because the diffusing member is an optional component for the ultraviolet light irradiation device in terms of improving the light output efficiency by reducing the angle of incidence on the optical filter 6. However, the ultraviolet light irradiation devices (70, 80) shown in FIGS. 14 and 15 may also be provided with a diffusing member that diffuses the ultraviolet light output from the optical filter 6. This increases the output efficiency of light from the optical filter 6, and the diffusing member can widen the light distribution angle of the ultraviolet light. [Example]

[0103] The effect of widening the light distribution angle by using the diffusing member 5 was confirmed for the ultraviolet light irradiation device 10 shown in the above embodiment. Details of the ultraviolet light irradiation device 10 will be described later. FIG. 16 shows a measurement facility 40 for measuring the light distribution angle of the ultraviolet light irradiation device 10. The measurement facility 40 includes the ultraviolet light irradiation device 10, a rotating stage 30 for mounting the ultraviolet light irradiation device 10, and an illuminance meter 31. Note that a UV POWER METOR C8026 manufactured by Hamamatsu Photonics KK is used as the illuminance meter 31.

[0104] The measurement equipment 40 includes a rotation stage 30, an ultraviolet light irradiation device 10 placed on the rotation stage 30, and an illuminance meter 31 positioned at a distance d1 of 1000 (mm) from the ultraviolet light irradiation device 10. The position of the rotation stage 30 when the ultraviolet light irradiation device 10 is positioned opposite the illuminance meter 31 so that the illuminance meter 31 is positioned on the optical axis L1 of the ultraviolet light irradiation device 10 is defined as an initial position P0. The rotation stage 30 is rotated from the initial position P0 in a rotation direction R shown in FIG. 16. In FIG. 16, the rotation stage 30 and ultraviolet light irradiation device 10 at the initial position P0 are indicated by dotted lines, and the rotation stage 30 and ultraviolet light irradiation device 10 after rotating in the rotation direction R for a predetermined time are indicated by solid lines.

[0105] The angle θ4 formed between the optical axis L1 of the ultraviolet light irradiation device 10 and the light ray L3 incident on the illuminometer 31 from the ultraviolet light irradiation device 10 represents the rotation angle. The rotation angle θ4 was increased (by rotating the rotation stage 30) from an initial position P0 where the rotation angle θ4 was 0 degrees (deg), and the illuminance was measured with the illuminometer 31 while irradiating ultraviolet light from the ultraviolet light irradiation device 10 until the rotation angle θ4 reached 90 degrees (deg).

[0106] The relative illuminance was calculated based on the measured illuminance results. Relative illuminance is calculated by dividing the illuminance measured at an arbitrary rotation angle by the illuminance measured at a rotation angle of 0 degrees (deg). In other words, relative illuminance is the relative value of the illuminance of a ray of light traveling at an arbitrary angle, when the illuminance of a ray of light traveling in the direction of the optical axis is set to 1. Figure 17 shows a graph showing the relative illuminance with respect to changes in rotation angle.

[0107] Three curves are shown in Figure 17. Curve C1 represents the relative illuminance based on the measurement results of the ultraviolet light irradiation device C1. The ultraviolet light irradiation device C1 is equipped with an optical filter 6 but does not have a diffusing member 5. The C2 curve represents the relative illuminance based on the measurement results of the ultraviolet light irradiation device C2. The ultraviolet light irradiation device C2 is equipped with an optical filter 6 that transmits ultraviolet light in the wavelength band of 190 nm to 235 nm and substantially blocks ultraviolet light in the wavelength band of 240 nm to 280 nm or less, and is equipped with a diffusing member 5 made of a PTFE sheet (thickness: 0.1 mm). The PTFE sheet used here is a "Naflon PTFE sheet" manufactured by Nichias Corporation (sheet thickness: 0.1 mm). The C3 curve is the calculated orientation distribution curve of an ideal perfect diffusion, which is calculated by the cosine value at each rotation angle.

[0108] A comparison of the C1 and C3 curves reveals that the angular range of relative illuminance narrows from the ideal orientation distribution curve of perfect diffusion by providing the optical filter 6. However, a further comparison with the C2 curve reveals that the provision of the diffusing member 5 results in an ideal orientation distribution curve close to perfect diffusion.

[0109] The light distribution angle is calculated by multiplying the rotation angle at which the relative illuminance becomes 0.50. From Figure 17, the light distribution angle of the ultraviolet light irradiation device C1 is 58 degrees (29 × 2), and the light distribution angle of the ultraviolet light irradiation device C2 is 108 degrees (54 × 2). It can be seen that the provision of the diffusing member 5 significantly increases the light distribution angle.

[0110] The above results are for when a PTFE sheet is used as the diffusing member 5, but the light distribution angle is also expanded when a diffusing sheet other than a PTFE sheet or a diffusing film is used as the diffusing member 5, just like when a PTFE sheet is used.

[0111] Figure 18 shows the relative total luminous flux of an ultraviolet light irradiation device using PTFE sheets of different thicknesses as the diffusing member 5. Figure 18 is a graph with the thickness of the PTFE sheet on the horizontal axis and the relative total luminous flux on the vertical axis. The relative total luminous flux is calculated as the ratio of the total luminous flux emitted from an ultraviolet light irradiation device having each sheet thickness to the total luminous flux emitted from the ultraviolet light irradiation device without a diffusing member. The total luminous flux represents the sum of the luminous flux emitted in all directions from the light source, and can be roughly calculated from the illuminance measurements at each rotation angle using the measuring equipment 40 shown in Figure 16.

[0112] As shown in Figure 18, the thicker the PTFE sheet, the lower the relative total luminous flux. This indicates that the thicker the PTFE sheet, the more ultraviolet light is attenuated. When the PTFE sheet is less than 1 mm, the relative total luminous flux is 0.2 or greater, which is preferable. When the PTFE sheet is less than 0.5 mm, the relative total luminous flux is 0.4 or greater, which is more preferable. When the PTFE sheet is less than 0.2 mm, the relative total luminous flux exceeds 0.6, which is even more preferable. Note that even when the PTFE sheet is made thinner, the luminous intensity distribution curve, which is close to perfect diffusion, is hardly impaired. Even when the PTFE sheet is made 0.05 mm thick, a luminous intensity distribution curve close to the C2 curve in Figure 17 is obtained. [Explanation of symbols]

[0113] 2: Housing 2a: First slot 2b: Second slot 3: Excimer lamp 4: Removal section 5: Diffusion material 5b: Diffusion film 5s: Diffusion sheet 6: Optical filter 10: Ultraviolet light irradiation device 11:Optical element 11a: Optical lens 11b:Reflector 13:Fixed part 15: Quartz glass 20: Ultraviolet light irradiation device 23: Fixed part 25:Protrusion 30: Rotating stage 31:Luminance meter 40: Measuring equipment 51: Mounting part 52: Screw 60: Ultraviolet light irradiation device 70: Ultraviolet light irradiation device 80: Ultraviolet light irradiation device

Claims

1. a light source that emits ultraviolet light in the range of 190 nm to 235 nm; a housing that houses the light source; an extraction unit that extracts the ultraviolet light emitted from the light source to the outside of the housing; an optical filter that transmits ultraviolet light in a wavelength band of 190 nm to 235 nm and does not substantially transmit ultraviolet light in a wavelength band of 240 nm to 280 nm, wherein light emitted from the optical filter has a smaller light distribution angle than light incident on the optical filter; an extracting section including a diffusing member that is disposed in contact with the optical filter on the ultraviolet light emission side of the optical filter and that diffuses the ultraviolet light;

2. 2. The ultraviolet light irradiation device according to claim 1, wherein the diffusing member is a diffusing sheet.

3. 3. The ultraviolet light irradiation device according to claim 2, wherein the diffusion sheet is mainly made of PTFE.

4. The ultraviolet light irradiation device according to claim 2 , further comprising a fixing portion for fixing the diffusion sheet around the extraction portion.

5. 2. The ultraviolet light irradiation device according to claim 1, wherein the diffusing member is a diffusing film formed on the optical filter.

6. 6. The ultraviolet light irradiation device according to claim 5, wherein the diffusion film is mainly composed of silica or alumina.

7. 2. The ultraviolet light irradiation device according to claim 1, wherein the diffusing member is disposed between the optical filter and a transmission plate that transmits the ultraviolet light.

8. 2. The ultraviolet light irradiation device according to claim 1, wherein the thickness of the diffusing member is less than 1 mm.

9. 9. The ultraviolet light irradiation device according to claim 8, wherein the thickness of the diffusing member is less than 0.5 mm.

10. 2. The ultraviolet light irradiation device according to claim 1, wherein the light source is an excimer lamp.

11. A method for using an ultraviolet light irradiation device, comprising: arranging the ultraviolet light irradiation device according to any one of claims 1 to 10 so that at least a portion of the emitted ultraviolet light is irradiated toward a manned space; and causing the ultraviolet light irradiation device to emit the ultraviolet light.

12. a light source that emits ultraviolet light in the range of 190 nm to 235 nm; a housing that houses the light source; an extraction unit that extracts the ultraviolet light emitted from the light source to the outside of the housing; an optical filter that transmits ultraviolet light in a wavelength band of 190 nm to 235 nm and does not substantially transmit ultraviolet light in a wavelength band of 240 nm to 280 nm, and that makes the light distribution angle of light emitted from the optical filter smaller than that of light incident on the optical filter; the housing has a mounting portion for mounting a diffusing member that is disposed in contact with the optical filter on the ultraviolet light emission side of the optical filter and that diffuses the ultraviolet light. Ultraviolet light irradiation device.

13. ultraviolet light is emitted from a light source that emits ultraviolet light of 190 nm to 235 nm; an optical filter that transmits ultraviolet light in a wavelength band of 190 nm to 235 nm and does not substantially transmit ultraviolet light in a wavelength band of 240 nm to 280 nm, wherein light emitted from the optical filter has a smaller light distribution angle than light incident on the optical filter, and the optical filter selectively transmits the ultraviolet light emitted from the light source; a diffusing member disposed on the exit side of the optical filter in contact with the optical filter to diffuse the light exiting from the optical filter; A method for irradiating ultraviolet light, comprising:

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