Disinfection procedures and disinfection equipment

Abstract

Disinfection procedures, comprehensive: Irradiation of a fungus and a bacterium with light comprising violet light with a light emission peak having (i) a half-width of at most 20 nm and (ii) a peak wavelength greater than 380 nm and less than 400 nm, wherein the light: does not include UV-A light with a light emission peak having a peak wavelength that is contained within an entire range from 350 nm to 380 nm, inclusive, and does not contain a light emission peak with a light emission intensity greater than the light emission intensity of the light emission peak of the violet light in a wavelength range from 350 nm to 450 nm, inclusive.

Description

[Technical field]

[0001] The present invention relates to disinfection methods and disinfection devices that utilize irradiation with light. [State of the art]

[0002] Mold fungi occur in wet areas, such as bathrooms or kitchens, or in damp locations, such as ceiling spaces or under floors. For example, a technique for removing mold fungi is known that uses a photocatalyst. For instance, patent document 1 discloses the activation of a photocatalyst by irradiating the photocatalyst with ultraviolet light to perform disinfection and deodorization through a photocatalytic reaction.

[0003] US 2014 / 0303547 A1 describes a phototherapeutic device, a method, and its use. US 2008 / 0119352 A1 describes a photocatalytic composition responsive to visible light and a method for its preparation. CN 102573926 B describes a method for inactivating viruses and an article provided with antiviral properties. [Document List][Patent Document]

[0004] [PTL 1] Japanese unexamined patent application with publication number 2006-200358 [Summary of the invention][Technical problem]

[0005] However, in the conventional technique described above, the floors and walls irradiated with ultraviolet light must be made of materials resistant to ultraviolet light. Furthermore, the photocatalyst must be applied beforehand, and consequently, the environments in which the technique can be used are limited.

[0006] In this respect, the present invention provides a versatile disinfection method and a versatile disinfection device. [Solution to the problem]

[0007] A disinfection method according to one aspect of the invention comprises irradiating a fungus and a bacterium with light comprising violet light having a light emission peak with (i) a half-width of at most 20 nm and (ii) a peak wavelength greater than 380 nm and less than 400 nm, wherein the light: does not include UV-A light with a light emission peak having a peak wavelength that is contained within an entire range from 350 nm to 380 nm, inclusive, and does not include a light emission peak with a light emission intensity greater than the light emission intensity of the light emission peak of the violet light in a wavelength range from 350 nm to 450 nm, inclusive.

[0008] Furthermore, a disinfection device according to one aspect of the invention comprises a light source that irradiates a fungus and a bacterium with light having a light emission peak with (i) a half-width of at most 20 nm and (ii) a peak wavelength greater than 380 nm and less than 400 nm, wherein the light: does not include UV-A light with a light emission peak having a peak wavelength that is contained within an entire range from 350 nm to 380 nm, inclusive, and does not include a light emission peak with a light emission intensity greater than the light emission intensity of the light emission peak of the violet light in a wavelength range from 350 nm to 450 nm, inclusive. [Advantageous effects of the invention]

[0009] According to the present invention, a versatile disinfection method and a versatile disinfection device can be provided. [Brief description of the drawings] Fig. Figure 1 is a schematic diagram of a bathroom to which a disinfection device according to embodiment 1 is applied; Fig. Figure 2 is a cross-sectional view of a drain opening where the disinfection device according to embodiment 1 is installed; Fig. Figure 3 is a block diagram showing the construction of the disinfection device according to embodiment 1; Fig. Figure 4 is a graph showing a spectral distribution of violet light emitted by the disinfection device according to embodiment 1; Fig. Figure 5 is a graph showing a spectral distribution of UV-A light, which has been used as a comparison example in embodiment 1; Fig. Figure 6 is a diagram showing results of examining fungi / bacteria in the case where the fungi / bacteria are irradiated with UV-A light and violet light according to embodiment 1; Fig. Figure 7 is a diagram showing the results of a first experiment examining fungi / bacteria in the case where the fungi / bacteria are irradiated with different intensities of violet light according to embodiment 1; Fig. Figure 8 is a diagram showing test results in the case where Pseudomonas aeruginosa is irradiated with different intensities of violet light according to embodiment 1; Fig. Figure 9 is a diagram showing test results in the case where Rhodotorula (rhodotorula) is irradiated with different intensities of violet light according to embodiment 1; Fig. Figure 10 is a block diagram showing the construction of a disinfection device according to embodiment 2; Fig. Figure 11 is a graph showing a spectral distribution of UV-B light emitted by the disinfection device according to embodiment 2; Fig. Figure 12 is a diagram showing results of the examination of fungi / bacteria in the case where the fungi / bacteria are irradiated with varying intensities of UV-B light according to embodiment 2; Fig. Figure 13 is a cross-sectional view of a drain opening in which a disinfection device according to embodiment 3 is installed; and Fig. Figure 14 is a diagram showing results of the examination of fungi / bacteria in the case where the fungi / bacteria are irradiated with light using a photocatalyst according to embodiment 3. [Description of embodiments]

[0010] A disinfection method and a disinfection device according to embodiments of the present invention are described in detail below with reference to the drawings. It should be noted that each of the embodiments described below represents a specific example. Therefore, numerical values, shapes, materials, structural components, the arrangement and connection of the structural components, steps, and the sequence of steps, etc., shown in the following embodiments are merely examples and are not intended to limit the scope of the present invention. Furthermore, in the following embodiments, structural components not specified in any of the independent claims, which define the broadest concepts of the present invention, are described as arbitrary structural components.

[0011] Furthermore, the figures are schematic diagrams and not necessarily exact representations. Therefore, for example, the scales, etc., are not necessarily uniform across the figures. Additionally, essentially identical components in the figures are assigned the same reference symbols, and any overlapping descriptions are omitted or simplified. [Version 1][Overview]

[0012] A disinfection method and a disinfection device according to this embodiment provide disinfection by irradiating fungi / bacteria with light. It should be noted that in this description, disinfection refers to suppressing the proliferation of fungi / bacteria. In particular, disinfection refers not only to the destruction, annihilation, or elimination of fungi / bacteria through decomposition, but also to suppressing the growth or occurrence of fungi / bacteria. Suppressing the growth of fungi / bacteria includes not only causing a complete cessation of growth, but also reducing the growth rate.

[0013] The Fig. Figure 1 is a schematic diagram of a bathroom 1 to which a disinfection device 100 according to this embodiment is applied. Fig. Figure 2 is a cross-sectional view of a drain opening 10, on which the disinfection device 100 is installed according to this embodiment.

[0014] The disinfection device 100 according to this embodiment is applied to a wet area facility, such as a bathroom 1 located in the Fig. Figure 1 shows that the wet area equipment is not limited to bathroom 1 and can include a kitchen, toilet, sink, pipework, etc. Furthermore, the disinfection device 100 is not only used in wet area equipment but also in damp locations such as ceiling spaces or under floors.

[0015] Bathroom 1, which is located in the Fig. Figure 1 shows, for example, a bathroom module comprising a bathtub 2, a floor 3, walls 4, and a ceiling 5. The bathtub 2, floor 3, walls 4, and ceiling 5 are formed from components made using a resin material, etc. In this embodiment, the resin material used for the bathtub 2, floor 3, walls 4, and ceiling 5 does not need to be resistant to ultraviolet light.

[0016] As it is in the Fig. As shown in Figure 1, a drainage opening 10 is provided in the floor 3. As shown in the Fig. As shown in Figure 2, the drain opening 10 comprises a water collection chamber 11 and a cover 12. At least one through-hole 13 is provided in the cover 12. Water, etc., that has dripped onto the base 3 flows through the through-hole 13 into the water collection chamber 11 and is directed to a drain pipe. It should be noted that a filter for removing dirt, etc., may be provided between the water collection chamber 11 and the drain pipe.

[0017] In this embodiment, the disinfection device 100 is provided on the underside of the cover 12 of the drain opening 10, as shown in the Fig. Figure 2 shows that the disinfection device 100 irradiates the interior of the water collection chamber 11 with light, including violet light. The disinfection device 100 suppresses the growth of fungi / bacteria within the drain opening 10.

[0018] In particular, the fungi / bacteria include true fungi (eumycetes), such as molds and yeasts, or bacteria, such as eubacteria. In this embodiment, true fungi are, for example, Cladosporium (or Cladosporioides), Rhodotorula, etc. Bacteria are, for example, Pseudomonas aeruginosa. The disinfection device 100 suppresses the proliferation of true fungi, such as Cladosporium and Rhodotorula, as well as bacteria, such as Pseudomonas aeruginosa.

[0019] It should be noted that the location where the disinfection device 100 is installed is not limited to the inside of the drain opening 10. For example, as shown in the Fig. Figure 1 shows a lighting device 20 installed in the wall 4 of bathroom 1. The lighting device 20 can be a disinfection device 100. In other words, the lighting device 20 can emit light that includes violet light. In this case, the lighting device 20 can switch between emitting white light and violet monochromatic light. Accordingly, by acting as a disinfection device 100, the lighting device 20 can suppress the growth of fungi / bacteria that may occur in the bathtub 2, on the floor 3, the walls 4, and the ceiling 5, etc. [Setup of the disinfection device]

[0020] The disinfection device 100 according to this embodiment is described below with reference to the Fig. 2 and the Fig. 3 described. Fig. Figure 3 is a block diagram showing the construction of the disinfection device 100 according to this embodiment.

[0021] As it is in the Fig. 2 and the Fig. As shown in Figure 3, the disinfection device 100 comprises the light source 110, which emits light including violet light. The disinfection device 100 comprises a housing 120 and an optical component 130. The disinfection device 100 further comprises a control circuit 140, a battery 150, a memory 160, and a switch 170.

[0022] The light source 110 is a light emitter that emits light including violet light. The light source 110 irradiates fungi / bacteria with the light including violet light. In this embodiment, the light source 110 emits light including violet light according to the current supplied by the battery 150.

[0023] As it is in the Fig. As shown in Figure 2, the light source 110 comprises a light-emitting diode (LED) 111 and the plate 112. The light source 110 is, for example, a so-called bare-chip assembly (COB) module, in which an unencapsulated chip (LED 111) is mounted directly on the plate 112.

[0024] The LED 111 is an example of a light-emitting element that emits light including violet light. The LED 111 emits, for example, monochromatic violet light.

[0025] The violet light emitted by LED 111 has a light emission peak with a maximum width at half maximum (FWHM) of 20 nm. It should be noted that the FWHM can be, for example, a maximum of 15 nm or a maximum of 10 nm.

[0026] The peak wavelength in the light emission peak of the violet light is greater than 380 nm and less than 400 nm. The light does not include UV-A light with a light emission peak having a peak wavelength contained within the entire range from 350 nm to 380 nm, inclusive. The light does not contain a light emission peak with a light emission intensity greater than the light emission intensity of the light emission peak of the violet light within a wavelength range from 350 nm to 450 nm, inclusive. Furthermore, the peak wavelength is the wavelength at the time when the light emission intensity in a spectral distribution of violet light is greatest (or maximum).

[0027] The LED 111 emits violet light with the [missing information] in the Fig. 4 spectral distributions shown. The Fig. Figure 4 is a graph showing the spectral distribution of violet light emitted by the disinfection device 100 according to this embodiment. It should be noted that in the Fig. 4. The horizontal axis represents the wavelength and the vertical axis represents the relative energy (intensity) of light. As shown in the Fig. As shown in Figure 4, the violet light emitted by LED 111 has a peak wavelength of about 390 nm and a half-width of about 10 nm.

[0028] It should be noted that the LED 111 can emit light that includes violet light and another wavelength component, rather than just monochromatic violet light. For example, in addition to violet light, the LED 111 can emit visible light that includes blue light, green light, etc. For example, the LED 111 can emit white light.

[0029] For example, a ceramic plate, a resin plate, or a metal-based plate can be used for plate 112. Plate 112 is attached to the base of housing 120. A metal wire or conductor (not shown in the figure) is provided for plate 112.

[0030] For example, the control circuit 140, which causes the LED 111 to light up, is provided on the board 112, and the LED 111 and the battery 150 are connected by means of the metal wire or metal conductor. It should be noted that the control circuit 140 can be provided as a separate body from the light source 110.

[0031] It should be noted that the light source 110 can be a surface mount device (SMD) module. In particular, a packaged LED element (SMD LED element) can be mounted on the plate 112. A packaged LED element comprises, for example, a resin housing having a cavity, an LED chip (LED 111) mounted within the cavity, and an encapsulating medium filled into the cavity.

[0032] Furthermore, the light source 110 can comprise a laser element, an organic electroluminescent (EL) element, etc., instead of the LED 111. Alternatively, the light source 110 can be a discharge lamp, such as a fluorescent lamp.

[0033] The housing 120 comprises the light source 110, the control circuit 140, the battery 150, and the memory 160. The housing 120 is made, for example, of a resin material such as polybutylene terephthalate (PBT) or a metal material. The housing 120 is, for example, a flat, bottomed, essentially cylindrical container; however, the size and shape of the housing 120 are not limited to this.

[0034] The housing 120 is attached to the underside of the cover 12 of the drain opening 10, for example, by means of adhesive tape (not shown in the figure). In particular, the housing 120 is arranged with its optical component 130 facing downwards, so that light is emitted downwards. It should be noted that the method of attaching and orienting the housing 120 is not limited to this. For example, the housing 120 can be screwed to the cover 12 or the base 3 (a building material, such as a flooring material, that forms the base of the water collection chamber 11). Alternatively, the housing 120 can be arranged on the base of the water collection chamber 11 so that it emits light laterally.

[0035] The optical component 130 is located in front of (i.e., on the light-emitting side) the light source 110 and is attached to the housing 120. It should be noted that any gap between the housing 120 and the optical component 130 can be sealed using a water-resistant sealant, etc., to prevent the ingress of moisture.

[0036] The optical component 130, for example, causes the light emitted by the light source 110 to be dispersed (scattered) and exit as scattered light. Accordingly, the entire water collection chamber 11 of the outlet opening 10 can be illuminated by the light emitted by the optical component 130. It should be noted that the optical component 130 may have a lens function for scattering or condensing the light emitted by the light source 110.

[0037] The optical component 130 can, for example, act as a filter that removes a specified wavelength component. In particular, the optical component 130 can be an optical filter that removes wavelength components in the range of 350 nm to 380 nm, inclusive, from the light emitted by the light source 110.

[0038] In other words, optical component 130 can remove UV-A light. Furthermore, optical component 130 can remove UV-B light. Optical component 130 can remove wavelength components other than violet light.

[0039] In this context, removal means reducing the intensity of a wavelength component. Specifically, removal does not only mean removing it completely (i.e., reducing the intensity of a wavelength component to 0), but also reducing the intensity of a wavelength component below a predetermined threshold.

[0040] For example, if ultraviolet light is removed by the optical component 130, essentially no ultraviolet light is emitted to the outside of the disinfection device 100. Accordingly, the disinfection device 100 can be used even if the components to be irradiated (building materials forming the inner surface, etc., of the drain opening 10) are not resistant to ultraviolet light. Therefore, the versatility of the disinfection device 100 is increased.

[0041] Control circuit 140 regulates the irradiation conditions of the light, which includes violet light. For example, control circuit 140 controls the irradiation period, the start (or end) time of irradiation, and the irradiation method (light distribution, etc.). In particular, control circuit 140 controls the switching on and off of the light source 110. By supplying current to LED 111, which is provided by battery 150, control circuit 140 causes LED 111 to illuminate. Control circuit 140 is, for example, a microcontroller module.

[0042] The control circuit 140 controls the switching on and off of the light source 110, for example, based on sequence information stored in the memory 160. In particular, the control circuit 140 can have a time control function. For example, the control circuit 140 causes the light source 110 to continue emitting violet light for a predetermined first period (an irradiation period) and then causes the light source 110 to stop emitting violet light for a predetermined second period (a non-irradiation period). The control circuit 140 can control the light source 110 to alternate between the irradiation and non-irradiation periods. Accordingly, light irradiation and non-irradiation can be carried out in a suitable manner, and consequently, the disinfecting effect can be enhanced.

[0043] Furthermore, the control circuit 140 can control the switching on and off of the light source 110 based on an operating signal transmitted by the switch 170. Accordingly, the light source 110 can be switched on for disinfection at the time a user operates the switch 170, i.e., at the time desired by the user.

[0044] Battery 150 is a removable power source. It is housed in a casing (not shown in the figure) provided within the casing 120 and supplies power to the light source 110 via the control circuit 140. Battery 150 can be a primary power source, such as an alkaline or manganese battery, but is not limited to this. It can also be a rechargeable secondary power source.

[0045] Memory 160 is a non-volatile memory that stores a light irradiation program and process information, etc. The process information specifies, for example, the start and end times of the light irradiation. This information can also specify the duration of each irradiation period and non-irradiation period.

[0046] For example, the control circuit 140 reads the irradiation program and the sequence information from the memory 160 and controls the switching on and off of the light source 110 based on the irradiation program and the sequence information that are read out.

[0047] Switch 170 is a switch for toggling between light irradiation and non-irradiation. Switch 170 is, for example, positioned so that it is exposed to the outside of housing 120 and can be operated by a user. [First Experiment]

[0048] Next, an initial experiment is conducted to investigate the relationship between the wavelength of light with which a real fungus is irradiated by fungi / bacteria, and the growth of the real fungus is described. The fungi / bacteria subjected to the first experiment are Cladosporium and Rhodotorula.

[0049] In the first experiment, violet light and UV-A light are used to irradiate the fungi / bacteria. Each light source is described first.

[0050] As described above, violet light is a light with the spectral distribution shown in the Fig. Figure 4 shows that the violet light is a violet monochromatic light with a peak wavelength of about 390 nm and a light emission peak with a half-width of about 10 nm.

[0051] UV-A light is a type of light with the properties found in the Fig. 5 spectral distributions shown. The Fig. Figure 5 is a graph showing the spectral distribution of UV-A light, which is used as a comparison example in this embodiment. It should be noted that in the Fig. 5. The horizontal axis represents the wavelength and the vertical axis represents the relative energy (intensity) of light. As shown in the Fig. As shown in Figure 5, the UV-A light exhibits a light emission peak in which the peak wavelength lies within a range of 350 nm to 380 nm, inclusive. The full width at half maximum (FWHM) is approximately 10 nm. (Violet light irradiation)

[0052] First, the condition of the fungi / bacteria when irradiated with violet light is described below with reference to the Fig. 6 described. Fig. Figure 6 is a diagram showing results of examining fungi / bacteria in the case when the fungi / bacteria are irradiated with each of the UV-A light and the violet light according to this embodiment.

[0053] An investigation was carried out by examining Petri dishes from above through a visual inspection (in particular by imaging using a camera). Fig. Figure 6 shows the images of the Petri dishes that were taken.

[0054] It should be noted that in the Fig. 6. The small spots are Rhodotorula, and the pasty forms are Cladosporium. The same applies to those described later. Fig. 7, Fig. 12 and Fig. 14.

[0055] In this experiment, light irradiation and non-irradiation were repeatedly performed for predetermined periods using specified amounts of Cladosporium and Rhodotorula cultured in Petri dishes. The condition of the fungi / bacteria was examined at predetermined time points. The light irradiation time was set to 18 hours, and the non-irradiation time to 6 hours. The intensity of the violet light during irradiation was 3000 µW / cm². 2 It should be noted that this value was measured with a Konica Minolta UM-360.

[0056] (i) The first examination was carried out after the initial light exposure had been carried out for 18 hours (i.e., at the point when the total exposure time was 18 hours and 18 hours had elapsed since the start).

[0057] (ii) The second examination was carried out 6 hours after the start of light exposure, following 6 hours of non-exposure, 18 hours of exposure and 6 hours of non-exposure consecutively after the first examination (i.e., at the time when the total exposure time was 42 hours and 54 hours had elapsed since the start).

[0058] (iii) The third examination was carried out when 12 hours of irradiation and 6 hours of non-irradiation had been carried out following the second examination (i.e., when the total irradiation time was 54 hours and 72 hours had elapsed since the start).

[0059] (iv) The fourth examination was carried out after 40 hours of non-irradiation following the third examination (i.e., at the point when the total irradiation time was 54 hours and 112 hours had elapsed since the start).

[0060] Furthermore, as a comparative example, investigations with the same temporal sequences as the above (i) to (iv) were carried out in the state in which absolutely no light irradiation was performed (“NO IRRITATION” in the Fig. 6).

[0061] As it is in the Fig. Figure 6 shows that, without light irradiation, thin growth of Cladosporium was observed after 18 hours. Subsequently, growth of both Cladosporium and Rhodotorula was observed over time.

[0062] In contrast, when violet light irradiation was performed, no growth of Cladosporium and Rhodotorula could be detected by visual examination in any of the following cases: after 18 hours, after 54 hours, and after 72 hours from the start of the treatment. Thus, it is evident that the growth of Cladosporium and Rhodotorula was suppressed by irradiation with violet light.

[0063] Furthermore, a small amount of Cladosporium and Rhodotorula was detected 112 hours after the start of the treatment, specifically at the point when 46 hours had elapsed since the last irradiation. Therefore, it is evident that the violet light did not cause the complete destruction of Cladosporium and Rhodotorula.

[0064] As described above, violet light irradiation can suppress growth without destroying fungi / bacteria such as Cladosporium and Rhodotorula. Therefore, even when violet light irradiation is applied, beneficial fungi / bacteria are not destroyed, and consequently, they can coexist. Destroying beneficial fungi / bacteria can cause faster-than-normal growth of harmful fungi / bacteria. Therefore, according to this embodiment, it is possible to suppress growth without destroying fungi / bacteria, and as a result, a disinfecting effect can be enhanced.

[0065] Since the fungi / bacteria are not killed even when irradiated with violet light, it should be noted that the growth of the fungi / bacteria will continue if violet light irradiation is not carried out for a long time. However, as stated in (iii) in the Fig. As shown in Figure 6, even after a 6-hour period without irradiation following violet light exposure, the growth of Cladosporium and Rhodotorula was sufficiently suppressed. In other words, it is evident that violet light irradiation does not need to be continuous. For example, a sufficient disinfection effect can be achieved by repeating violet light irradiation followed by a period without irradiation, while reducing energy consumption. (UV-A light irradiation)

[0066] Next, the condition of fungi / bacteria when irradiated with UV-A light instead of violet light will be described, with reference to the Fig. 6 described. The UV-A light used here exhibits the properties described in the Fig. Figure 5 shows the spectral distribution. The experimental conditions are identical to those described above for violet light. Investigations were carried out for two cases: high-intensity UV-A irradiation and low-intensity UV-A irradiation. Specifically, the UV-A light intensities during irradiation were 270 µW / cm². 2 and 100 µW / cm 2 It should be noted that these values ​​were measured using a Topcon UVR2.

[0067] Regardless of the intensity of the UV-A light, the growth of both Cladosporium and Rhodotorula was observed over time. It is evident that the growth of fungi / bacteria is suppressed compared to the case where no light irradiation is applied; however, the growth-suppressing effect is low compared to when ultraviolet light irradiation is applied.

[0068] It is generally known that ultraviolet light has a bactericidal effect. However, based on the experimental results described above, it is evident that even when fungi / bacteria were irradiated with UV-A light, the suppression effect on fungi / bacteria was insufficient. Therefore, for example, by using the power required to emit UV-A light instead to emit ultraviolet light, fungal / bacterial growth suppression can be effectively implemented. (Violet light intensity)

[0069] Based on the experimental results described above, it is evident that irradiation with violet light can suppress fungal / bacterial growth. Therefore, the results of an experiment establishing the relationship between violet light irradiation intensity and the suppressive effect on fungal / bacterial growth are described below.

[0070] The Fig. Figure 7 is a diagram showing the results of examining fungi / bacteria when irradiated with varying intensities of violet light according to this embodiment. The examination of the fungi / bacteria was carried out under conditions different from those in the experiment described in the Fig. Figure 6 is shown. Specific details are as described below.

[0071] (i) The first examination was carried out after an initial 20-hour violet light irradiation (i.e., at the point when the total irradiation time was 20 hours and 20 hours had elapsed since the start).

[0072] (ii) The second examination was carried out when 26 hours of irradiation had been carried out following a 5-hour non-irradiation (standby) period after the first examination (i.e., when the total irradiation time was 46 hours and 51 hours had elapsed since the start).

[0073] (iii) The third examination was carried out when 14 hours of non-irradiation had elapsed since the second examination (i.e., when the total irradiation time was 46 hours and 65 hours had elapsed since the start).

[0074] (iv) The fourth examination was carried out when a further 9 hours of non-irradiation had elapsed since the third examination (i.e., when the total irradiation time was 46 hours and 74 hours had elapsed since the start).

[0075] The intensity of the incident violet light was 3000 µW / cm². 2 , 1400 µW / cm 2 , 1100 µW / cm 2 and 500 µW / cm 2 It should be noted that these values ​​were measured with a Konica Minolta UM-360. Furthermore, the case where no light exposure was performed is also shown as a comparison example.

[0076] As it is in the Fig. As shown in Figure 7, the suppression effect on fungi / bacteria varies depending on the intensity of the violet light during irradiation. In particular, the respective test cases demonstrate that the growth of Cladosporium and Rhodotorula is suppressed more strongly the higher the intensity of the violet light. Furthermore, even in cases where the samples were left unirradiated after violet light exposure, it is evident that the occurrence of Cladosporium and Rhodotorula was more strongly suppressed when the violet light irradiation was performed at a higher intensity. [Second Experiment]

[0077] Next, a second experiment is described, which was conducted to investigate the relationship between the wavelength of light irradiated by the fungi / bacteria and the growth of the bacteria. The fungus used in the second experiment was Pseudomonas aeruginosa. It should be noted that the second experiment was also carried out in the same manner with Rhodotorula to verify the reliability of the results of the first experiment. (Experiment conditions)

[0078] The bacterial test culture was prepared as described below. For Pseudomonas aeruginosa, a frozen strain was cultured for two days at 36 ± 2 °C on tryptic soybean agar (Difco, hereinafter referred to as TSA) plating medium. For Rhodotorula, a frozen strain was cultured for two days at 26 ± 2 °C on potato dextrose seagar (Nissui Pharmaceutical Co., Ltd., PDA). Each colony developed was scraped and cultured to approximately 104 CFU / ml in sterilized ion-exchange water to obtain a bacterial test culture.

[0079] Furthermore, filtering 1 ml of the bacterial test culture through a membrane filter cut to 1 / 4 size captured approximately 104 CFU of bacteria in the filter, thus providing a test sample. Each test sample was placed on the surface of a moisture-retaining agar medium (1.5% agar medium) in a Petri dish, and the light irradiation test was performed. It should be noted that a test sample for maintenance in the dark without light irradiation was also prepared as a control.

[0080] As in the first experiment, the light used to irradiate the fungi / bacteria was a violet monochromatic light with a peak wavelength of 390 nm and a light emission peak with a half-width of approximately 10 nm, as described in the Fig. Figure 4 shows the method used. Irradiation was carried out using violet light at three different intensities. In particular, the irradiation intensities were set to 200 µW / cm². 2 , 1000 µW / cm 2 , 2000 µW / cm 2 The setup was adjusted with a moisture-retaining quartz plate placed on the Petri dish. It should be noted that the actual irradiance values ​​measured with a Konica Minolta UM-360 were 200 µW / cm². 2 , 1100 µW / cm 2 , 2400 µW / cm 2 The exposure times with violet light were continuous for 24 hours and 48 hours.

[0081] Bacterial counting after light irradiation was performed as described below. First, the test sample was collected in a Stomacher plastic bag pre-filled with 10 ml of a soy-casein-digestible-cithin-polysorbate (SCDLP) brewing medium (Eiken Chemical Co., Ltd.). The sample was then homogenized using a Stomacher (Organo Co.) for two minutes to wash the test bacteria from the sample. The washed liquid was used as the sample solution for bacterial counting.

[0082] Tenfold dilutions of the sample solution were prepared with physiological saline, and cultivation of each bacterium was carried out after transferring 1 ml of each stock solution and the diluted solutions to Petri dishes. Specifically, Pseudomonas aeruginosa was mixed with approximately 20 ml of TSA, allowed to solidify, and then cultured for 48 hours at 36 ± 2 °C. Rhodotorula was mixed with approximately 20 ml of PDA, allowed to solidify, and then cultured for three to five days at 26 ± 2 °C. After cultivation, the bacterial count for each test sample was obtained by counting the colonies that developed in each medium. It should be noted that multiple test samples were used under each condition, and the bacterial count is the average of the bacterial counts of the respective test samples under the same conditions, or in other words, the average bacterial count. (Results of the experiment)

[0083] The results of the second experiment are presented below, with reference to the Fig. 8 and the Fig. 9 described. Fig. Figure 8 is a diagram showing test results in the case where Pseudomonas aeruginosa was irradiated with varying intensities of violet light according to this embodiment. Fig. Figure 9 is a diagram showing test results in the case where Rhodotorula was irradiated with varying intensities of violet light according to this embodiment. Fig. 8 and the Fig. Figure 9 shows images of the media in which the sample solutions were cultured for bacterial counting. Since the initial state under violet light irradiation is identical to the initial state in the dark, one illustration is omitted.

[0084] As it is in the Fig. As shown in Figure 8, when violet light irradiation was performed, virtually no proliferation of Pseudomonas aeruginosa could be observed. In particular, in each case, an irradiation intensity of 200 µW / cm² was achieved. 2 , 1000 µW / cm 2 and 2000 µW / cm 2 The average bacterial count is a value less than 10 CFU per test sample.

[0085] In contrast, under the dark condition, Pseudomonas aeruginosa was found to multiply over time. Specifically, the average bacterial count after 24 hours of irradiation was 4.0 × 10⁻⁶. 5 CFU and the average bacterial count after 48 hours of irradiation was 9.7 × 10 5 CFU.

[0086] Based on the above, it is evident that irradiating Pseudomonas aeruginosa with violet light reduced the bacterial count, i.e., destroyed Pseudomonas aeruginosa. It is evident that, in addition to suppressing the growth of Pseudomonas aeruginosa, violet light also has a bactericidal effect.

[0087] In the same way as in the Fig. Figure 9 shows that when violet light irradiation was performed, there was a difference in the bactericidal effect depending on the irradiation intensity. This was particularly evident when the irradiation intensity was 200 µW / cm². 2 The average bacterial count after 24 hours of irradiation was 1.3 × 10 5 CFU and the average bacterial count after 48 hours of irradiation was 1.6 × 10 5 CFU. In this way it is evident that when the irradiance is 200 µW / cm²2 deception, Rhodotorula was not destroyed.

[0088] If, on the other hand, the irradiance is 1000 µW / cm² 2 and 2000 µW / cm 2 The average bacterial counts were less than 10 CFU per test sample. In other words, it is evident that Rhodotorula was destroyed by irradiation with high-intensity violet light.

[0089] Under dark conditions, Rhodotorula was found to multiply in the same way as under low irradiation intensity. In particular, the average bacterial count after 24 hours of irradiation was 1.9 × 10⁻⁶. 5 CFU and the average bacterial count after 48 hours of irradiation was 4.6 × 10 5 CFU. In every case, the average bacterial count was higher than in the case where the irradiation intensity was 200 µW / cm². 2This was the case. Based on this, it is evident that violet light irradiation, even at low irradiation intensity, suppresses the proliferation of Rhodotorula.

[0090] Based on the above, it is evident that irradiating Rhodotorula with violet light can suppress its reproduction, i.e., its growth. Although Rhodotorula cannot be destroyed if the irradiation intensity is low, the disinfecting effect is evident in the suppression of its growth. If the irradiation intensity is high, Rhodotorula can be destroyed. For example, if Rhodotorula is irradiated with violet light at an irradiation intensity of at least 200 µW / cm², it will be destroyed. 2 Irradiation can suppress the growth of Rhodotorula. Furthermore, if Rhodotorula is exposed to violet light with an irradiation intensity of at least 1000 µW / cm², it can be inhibited. 2Irradiation will destroy Rhodotorula.

[0091] It should be noted that the first experiment showed that Rhodotorula is not completely destroyed even at high irradiation intensity. In contrast, the second experiment resulted in the destruction of almost all Rhodotorula.

[0092] The difference in results is assumed to be due to the difference in the violet light irradiation method. Specifically, while the first experiment involved repeated violet light irradiation and non-irradiation periods, the second experiment used continuous violet light irradiation without any non-irradiation period. It is assumed that bacteria proliferated during the non-irradiation periods in the first experiment. Based on this, it appears that continuous violet light irradiation resulted in more effective suppression of bacterial growth.

[0093] It should be noted that, as demonstrated in the first experiment, even discontinuous violet light irradiation produces a suppressive effect on fungal / bacterial growth, i.e., a bactericidal effect. Therefore, discontinuous irradiation can suppress fungal / bacterial growth while reducing energy consumption. [Advantageous effects, etc.]

[0094] As described above, the disinfection method according to this embodiment includes irradiating fungi / bacteria with light comprising violet light with a light emission peak having (i) a half-width of not more than 20 nm and (ii) a peak wavelength greater than 380 nm and less than 400 nm.

[0095] Accordingly, as is permitted in the Fig. Figure 6 shows that violet light irradiation suppresses the growth of fungi / bacteria. Violet light is visible light and, compared to ultraviolet light, has fewer negative effects on the environment and organisms, such as the human body. Therefore, components containing resin materials, etc., that are not resistant to ultraviolet light can be irradiated with violet light, and the growth of fungi / bacteria can be suppressed. Furthermore, since a photocatalyst is not used, there is no need to apply one beforehand, and use in locations where a photocatalyst cannot be applied is possible. In this way, a versatile disinfection method can be provided according to this embodiment.

[0096] Furthermore, unlike ultraviolet light, violet light can suppress the growth of fungi / bacteria, but it does not destroy them. Therefore, when violet light is used, beneficial fungi / bacteria are not destroyed. In other words, the simultaneous presence of fungi / bacteria is possible. Consequently, since beneficial fungi / bacteria can also suppress the growth of harmful fungi / bacteria, the disinfecting effect can be further enhanced.

[0097] Furthermore, the light used to irradiate the fungi / bacteria does not include UV-A light with a light emission peak at a peak wavelength within the entire range of 350 nm to 380 nm, inclusive. Furthermore, the light does not include a light emission peak with an emission intensity greater than that of the violet light emission peak in the wavelength range of 350 nm to 450 nm, inclusive.

[0098] Since UV-A light, which has no suppressive effect on the growth of fungi / bacteria, is not included, the growth of fungi / bacteria can be effectively suppressed, as described in the Fig. Figure 6, etc., shows this. For example, the current fed into light source 110 can be used efficiently for violet light irradiation without being used for UV-A light irradiation, which does not contribute to disinfection. In this way, the energy consumption required to carry out the disinfection process can be reduced, and consequently, energy savings can be achieved.

[0099] Furthermore, for example, the irradiation with violet light and the non-irradiation are repeated during the treatment.

[0100] Accordingly, by providing a period during which violet light irradiation is not carried out, the growth of fungi / bacteria can be suppressed while reducing energy consumption.

[0101] Furthermore, the fungi include, for example, Cladosporium or Rhodotorula.

[0102] Accordingly, the growth of Cladosporium, Rhodotorula, etc., which tend to occur in wet area facilities such as bathrooms or kitchens, or in damp places such as ceiling spaces or under floors, can be effectively suppressed.

[0103] Furthermore, the bacterium Pseudomonas aeruginosa is present.

[0104] When a person with impaired immunity is exposed to Pseudomonas aeruginosa, there is a risk of Pseudomonas aeruginosa infection. The disinfection device 100 according to this embodiment can suppress the growth of Pseudomonas aeruginosa and is therefore useful for disease prevention.

[0105] Furthermore, the disinfection device 100 according to this embodiment comprises a light source 110 which irradiates fungi / bacteria with light having a light emission peak with (i) a half-width of at most 20 nm and (ii) a peak wavelength greater than 380 nm and less than 400 nm, wherein the light: does not include UV-A light with a light emission peak having a peak wavelength that is contained within an entire range from 350 nm to 380 nm, inclusive, and does not include a light emission peak with a light emission intensity greater than the light emission intensity of the light emission peak of the violet light in a wavelength range from 350 nm to 450 nm, inclusive.

[0106] Accordingly, as in the disinfection procedure described above, violet light irradiation enables the suppression of the growth of fungi / bacteria.

[0107] Furthermore, the disinfection device 100 includes, for example, an optical filter (optical component 130) which is arranged between the light source 110 and the fungi / bacteria and removes wavelength components in a range from 350 nm to 380 nm, inclusive, from the light emitted by the light source 110.

[0108] Accordingly, the emission of UV-A light, which has no suppressive effect on the growth of fungi / bacteria, can be prevented. Since it is possible to prevent the deterioration of a component to be irradiated due to UV-A light, the Disinfection Device 100 can therefore be used in various locations. In other words, a versatile Disinfection Device 100 can be provided. [Version 2]

[0109] A disinfection method according to embodiment 2 irradiates fungi / bacteria not only with violet light but also with UV-B ultraviolet light. The disinfection effect can be further enhanced by using UV-B light. Furthermore, this embodiment increases versatility by eliminating the need for a photocatalyst, although this versatility is somewhat reduced because the component to be irradiated must be resistant to ultraviolet light. Details of the disinfection method and the disinfection device that carries out the disinfection method according to this embodiment are described below. [Setup of the disinfection device]

[0110] The Fig. Figure 10 is a block diagram showing the structure of the disinfection device 200 according to this embodiment. Compared to the disinfection device 100 according to embodiment 1, which is described in the Fig. As shown in Figure 3, the disinfection device 200 differs in that it comprises a light source 210 and a control circuit 240 instead of the light source 110 and the control circuit 140. The following description focuses on the features that differ from embodiment 1, and a description of common features may be omitted or simplified.

[0111] The light source 210 includes the violet light source 211 and the UV-B light source 212.

[0112] The violet light source 211, for example, emits light with the spectral distribution shown in the Fig. 4 is specified, as in embodiment 1. The violet light source 211 is, for example, the LED 111 in embodiment 1.

[0113] The UV-B light source 212 is an example of a light source that emits light including UV-B light. The UV-B light source 212 is, for example, a fluorescent lamp that emits UV-B light, but it is not limited to this. For example, the UV-B light source 212 could be a xenon lamp, a metal halide lamp, etc., and it could be a light-emitting solid-state element, such as an LED or a laser element.

[0114] The UV-B light source 212 emits, for example, UV-B light, which is present in the Fig. exhibits the spectral distribution shown in section 11. Fig. Figure 11 is a graph showing the spectral distribution of the UV-B light emitted by the disinfection device 200 according to this embodiment. It should be noted that in the Fig. 11 the horizontal axis represents the wavelength and the vertical axis represents the radiance (equivalent to the light intensity) at a point located 1 m in front of the UV-B light source 212.

[0115] The peak wavelength of the UV-B light emitted by the UV-B light source 212 is contained in the maximum light emission peak in a range from 280 nm to 350 nm, inclusive, as shown in the Fig. Figure 11 shows that it is acceptable for UV-B light to exhibit only a single light emission peak, as shown in the Fig. 4, Fig. 5, etc., is shown.

[0116] The control circuit 240 individually controls the irradiation conditions with violet light and the irradiation conditions with UV-B light. Specifically, the control circuit 240 individually controls the switching on and off of each of the violet light source 211, which emits violet light, and the UV-B light source 212, which emits UV-B light. For example, the control circuit 240 controls the switch-on period, the start (or end) time of the switch-on, and the illumination method (light distribution, etc.) of the violet light source 212. Accordingly, the disinfection device 200 can switch the light used to irradiate the fungi / bacteria between violet light and UV-B light.

[0117] In this embodiment, the control circuit 240 exclusively controls the switching on of the violet light source 211 and the UV-B light source 212. For example, the control circuit 240 reads sequence information stored in the memory 160 and controls the switching on and off of the violet light source 211 according to the sequence specified in the read sequence information. Furthermore, the control circuit 240 controls the switching on and off of the UV-B light source 212 when the switch 170 is actuated. Accordingly, the destruction of fungi / bacteria by UV-B light irradiation can be carried out as required at any necessary time, while the growth of fungi / bacteria is suppressed by violet light irradiation. [Results of the experiment]

[0118] Next, the results of an experiment conducted to investigate the relationship between the intensity of UV-B light irradiated on the fungi / bacteria and their growth are described. In this experiment, the UV-B light emitted by the fungi / bacteria in the Fig. 11 shows the spectral distribution of the light used to irradiate the fungi / bacteria.

[0119] The Fig. Figure 12 is a plot showing results of examining fungi / bacteria when irradiated with varying intensities of UV-B light according to this embodiment. The UV-B light used here exhibits the properties described in the Fig. Figure 11 shows the spectral distribution. The experimental conditions are identical to those in the case of the violet light described above.

[0120] The intensity of the UV-B light is 260 µW / cm².2 , 160 µW / cm 2 , 60 µW / cm 2 , 30 µW / cm 2 and 10 µW / cm 2 or less. It should be noted that these values ​​were measured with a Topcon UVR2. Although the Fig. 12, as a comparative example, also shows the case in which light irradiation is not carried out; this is identical to the one described in the Fig. 6 is shown.

[0121] As it is in the Fig. As shown in Figure 12, it is evident that when the intensity is 30 µW / cm 2 or more, the growth of Cladosporium and Rhodotorula was suppressed. Furthermore, it is evident that when the intensity was 10 µW / cm² 2 or less, a suppressive effect on growth was obtained compared to the case when light irradiation was not carried out.

[0122] Furthermore, even in case (iv), where the samples were left to stand for 46 hours after the last irradiation, Cladosporium and Rhodotorula were hardly detected. It can be assumed that the irradiation with UV-B light destroyed the fungi such as Cladosporium and Rhodotorula, especially when the intensity of the UV-B light was 260 µW / cm². 2 and 130 µW / cm 2 Cladosporium and Rhodotorula could not be detected by visual inspection and are therefore considered sufficiently destroyed. On the other hand, if the intensity of UV-B light was 60 µW / cm², Cladosporium and Rhodotorula could not be detected by visual inspection and are therefore considered to be sufficiently destroyed. 2 and 30 µW / cm 2 Despite the low UV-B light intensity, a small amount of Cladosporium and Rhodotorula was detected. This indicates that the bactericidal effect increased with the intensity of the UV-B light.

[0123] Based on the above, it is evident that Cladosporium and Rhodotorula can be destroyed by irradiation with UV-B light. Therefore, for example, switching between violet light irradiation and UV-B light irradiation allows for simple growth suppression (i.e., without destroying or causing the annihilation of fungi / bacteria) and the destruction of fungi / bacteria, depending on the intended use, to be employed appropriately.

[0124] For example, if violet light irradiation is insufficient and Cladosporium and Rhodotorula are growing, irradiation with UV-B light can destroy any existing growth. Therefore, even if fungi / bacteria such as Cladosporium and Rhodotorula reappear, their growth can be suppressed by regular violet light irradiation. [Advantageous effects, etc.]

[0125] As described above, in the disinfection process according to this embodiment, the light with which the fungi / bacteria are irradiated comprises UV-B light with a light emission peak whose peak wavelength is contained in a range from 280 nm to 350 nm, inclusive.

[0126] Accordingly, fungi / bacteria can be destroyed because the light used to irradiate them includes UV-B light. For example, depending on the situation, growth suppression of fungi / bacteria through irradiation with ultraviolet light and destruction or annihilation of fungi / bacteria through irradiation with UV-B light can be used appropriately. Therefore, since it is possible to utilize the levels of disinfection—for example, whether to destroy fungi / bacteria or to control their growth (inhibit their reproduction)—in an appropriate manner, the versatility of the disinfection process can be further increased.

[0127] Furthermore, since a photocatalyst is not used, there is no need to apply one beforehand, and use in locations where a photocatalyst cannot be applied is possible. In this way, a versatile disinfection method can be provided according to this embodiment.

[0128] Furthermore, this embodiment shows an example in which the violet light source 211 and the UV-B light source 212 are switched on exclusively to each other during various time sequences; however, the time sequence is not limited to this. In particular, the violet light source 211 and the UV-B light source 212 can be switched on simultaneously. In other words, the disinfection device 200 can irradiate fungi / bacteria with light comprising violet light and UV-B light.

[0129] Furthermore, it is acceptable for the light source 210 to comprise only a single LED (or a single type of LED). The LED can emit light that includes violet light and UV-B light. For example, the LED can emit light with a broad wavelength band that extends from the ultraviolet range to the visible light range. [Version 3]

[0130] In a disinfection process according to embodiment 3, a photocatalyst activated by visible light is used, which is further activated by violet light. This allows the disinfection effect to be increased. Furthermore, although the versatility may be somewhat reduced due to the need for preparations, such as the prior application of the photocatalyst, the versatility can be improved in the same way as in embodiment 1, in that no ultraviolet light is required. Details of the disinfection process according to this embodiment and of a disinfection system that carries out the disinfection process are described below. [Disinfection system]

[0131] The Fig. Figure 13 is a cross-sectional view of a drain opening 310 on which the disinfection device 100 according to this embodiment is installed. The disinfection system according to this embodiment is applied to the drain opening 310.

[0132] As it is in the Fig. As shown in Figure 13, the disinfection system comprises the disinfection device 100 and the photocatalyst 311. The disinfection device 100 is identical to the one described in embodiment 1.

[0133] The photocatalyst 311 is provided in a location where fungi / bacteria are prone to growth. Specifically, the photocatalyst 311 is positioned adjacent to the fungi / bacteria that have been found. For example, the photocatalyst 311 is applied to the surface of a component exposed to steam, such as a bathroom, or to a humid environment, such as ceiling spaces or under floors.

[0134] In particular, the photocatalyst 311 is applied to the surface of the component that is the target of the light irradiation by the disinfection device 100. In the Fig. In the example shown in Figure 13, the photocatalyst 311 is arranged on an exposed section in the water collection chamber 11 of the drain opening 310. In particular, the photocatalyst 311 is applied to the surface of a bottom component contained in the drain opening 310, the upper surface and the underside of the cover 12, and the wall surfaces of the through-hole 13.

[0135] It should be noted that according to the Fig. 13 the photocatalyst 311 is also applied to the surface of the base 3. This allows, when the lighting device 20, which is in the Fig. As shown in Figure 1, the disinfecting effect of the disinfecting device 100 is realized on the surface of the floor 3 according to this embodiment. Furthermore, the photocatalyst 311 can be applied to the light-emitting surface of the optical component 130.

[0136] Photocatalyst 311 is a material that is activated when irradiated with violet light. For example, photocatalyst 311 is a visible light-activated photocatalyst and comprises tungsten trioxide (W03).

[0137] It should be noted that in this embodiment, the photocatalyst 311 is shown by way of example as being applied to and fixed on a base component, etc., although the photocatalyst 311 is not limited to this. For example, the photocatalyst 311 can be sprayed into the water collection chamber 11 and the space within the bathroom 1 using an atomizer, etc.

[0138] Furthermore, if the disinfection device 100 emits ultraviolet light, such as UV-B light or UV-A light, the photocatalyst 311 can be an ultraviolet-activated photocatalyst. For example, the photocatalyst 311 can comprise titanium dioxide (TiO2), etc. [Results of the experiment]

[0139] Next, the results of an experiment conducted to investigate the relationship between the wavelength of light irradiated with fungi / bacteria and photocatalyst 311 and the growth of the fungi / bacteria are described.

[0140] The Fig. Figure 14 is a diagram showing the results of examining fungi / bacteria in the case where the photocatalyst 311 according to this embodiment was used and the fungi / bacteria were irradiated with light. The examination conditions for the fungi / bacteria are as specified below.

[0141] As a test subject, a solution containing a predetermined amount of Cladosporium and Rhodotorula is dripped onto the surface of a square-shaped base material to which photocatalyst 311 has been applied. The material is then irradiated with light for a predetermined period and subsequently left to stand without irradiation. Furthermore, as a comparative example, the case in which photocatalyst 311 is not applied and light irradiation is not carried out is also shown.

[0142] In this experiment, violet light, which is in the Fig. 4 exhibits the spectral distribution shown, and UV-A light, which is shown in the Fig. The spectral distribution shown in Figure 5 was used as the light with which the fungi / bacteria and photocatalyst 311 were irradiated. Specifically, when photocatalyst 311 was tungsten trioxide, irradiation was performed with both violet light and UV-A light. When the photocatalyst was titanium dioxide, irradiation was performed with UV-A light. The irradiation light intensity was 15 µW / cm². 2 in the case of violet light and 270 µW / cm 2 In the case of UV-A light, it should be noted that these values ​​were measured with a Topcon UVR2.

[0143] (i) The first examination was carried out after the light exposure had been carried out for the first 15 hours (i.e., at the point when the total exposure time was 15 hours and 15 hours had passed since the start).

[0144] (ii) The second examination was carried out when 7 hours of non-irradiation had elapsed since the first examination (i.e., when the total irradiation time was 15 hours and 22 hours had elapsed since the start).

[0145] (iii) The third examination was carried out when 25 hours of non-irradiation had elapsed since the first examination (i.e., when the total irradiation time was 15 hours and 40 hours had elapsed since the start).

[0146] (iv) The fourth examination was carried out when 50 hours of non-irradiation had elapsed since the first examination (i.e., when the total irradiation time was 15 hours and 65 hours had elapsed since the start).

[0147] As it is in the Fig. As shown in Figure 14, it is evident that, using photocatalyst 311, the fungi / bacteria in the section of the solution containing them that was in contact with photocatalyst 311 (especially the lower section of the solution) were decomposed. When photocatalyst 311 is tungsten trioxide, a disinfecting effect is observed in both cases of violet light and UV-A light. When photocatalyst 311 is titanium dioxide 311, a disinfecting effect is observed upon irradiation with UV-A light.

[0148] Since, on the other hand, the decomposition effect of photocatalyst 311 did not occur in the upper part of the solution, the presence of Cladosporium was observed in the samples irradiated with UV-A light. In contrast, Cladosporium could not be detected by visual inspection in the sample irradiated with violet light. This is identical to the results reported in the Fig. 6 shown and described in embodiment 1. [Advantageous effects, etc.]

[0149] As described above, in the disinfection process according to this embodiment, the photocatalyst 311, which is arranged adjacent to the fungi / bacteria during irradiation, is additionally irradiated with light.

[0150] Accordingly, activating photocatalyst 311 can decompose fungi / bacteria present in its vicinity. Therefore, the disinfecting effect can be further enhanced.

[0151] Furthermore, photocatalyst 311 is, for example, a tungsten oxide.

[0152] Accordingly, ultraviolet light need not be used, since tungsten trioxide is excited by violet light. Therefore, components containing a resin material, etc., that does not exhibit ultraviolet light resistance can be irradiated with violet light. In this way, a versatile disinfection method can be provided according to this embodiment.

[0153] It should be noted that tungsten trioxide is activated when irradiated with light with a wavelength of 450 nm or less. Therefore, although examples show tungsten trioxide being irradiated with violet or UV-A light, as illustrated in this embodiment, the excitation light is not limited to these. The tungsten trioxide can also be irradiated with UV-B light (such as that shown in the Fig.(shown in Figure 11). Alternatively, the tungsten trioxide can be irradiated with light including UV-B and violet light. Furthermore, the titanium dioxide can be irradiated with UV-B light. [Miscellaneous]

[0154] Although the disinfection method and the device according to the present invention are described on the basis of the foregoing embodiments, etc., the present invention is not limited to the foregoing embodiments.

[0155] For example, in the foregoing embodiments, examples of fungi / bacteria that are the objects of disinfection are Cladosporium, Rhodotorula, and Pseudomonas aeruginosa, but these are not the only examples. For instance, irradiation with violet light can be carried out on filamentous fungi that cause powdery mildew, leaf spot, etc.

[0156] Furthermore, since the disinfection methods and disinfection devices according to the foregoing embodiments can suppress the growth of molds and yeasts, the growth of insect pests that feed on molds and yeasts can also be suppressed. For example, the growth of lichens that feed on molds and yeasts can be suppressed. This can additionally suppress the growth of Cheyletids that feed on lichens.

[0157] In this way, by suppressing the growth of fungi / bacteria, such as molds and yeasts, the occurrence of pests that harm the human body can be suppressed. In particular, the disinfection processes and devices, in their respective embodiments, indirectly exhibit pest-repelling and pest-controlling effects.

[0158] Furthermore, although the preceding embodiments show, for example, an instance in which violet light irradiation and non-irradiation are repeated, the violet light irradiation is not limited to this. The violet light irradiation can be performed continuously with the fungi / bacteria. Furthermore, in the case of alternating irradiation and non-irradiation periods, the irradiation period can differ for each iteration. This also applies to the non-irradiation period.

[0159] Furthermore, the disinfection device 100 is shown, for example, in the preceding embodiments to include a battery 150, but this is not limited to the battery. The disinfection device 100 can have a power cable (plug) and be supplied with power from a mains power source. This avoids the risk of disinfection failing due to a depleted battery.

[0160] Furthermore, the disinfection device 100 need not include, for example, the control circuit 140, the memory 160, and the switch 170, etc. Instead, the disinfection device 100 may include a wireless communication module. The disinfection device 100 can receive a control signal for switching the light source 110 on and off from an external control device (or server device), etc., via wireless communication such as Wi-Fi (registered trademark), Bluetooth (registered trademark), etc. The disinfection device 100 can control the switching on and off of the light source 110 based on the received control signal.

[0161] It should be noted that, for example, the disinfection device 100 in the preceding embodiments is shown by way of example, such that it is installed in the drain opening 10 of the bathroom 1, but is not limited to this. The disinfection device 100 can be used in all environments that may come into contact with water or steam.

[0162] For example, the Disinfection Device 100 can be used in ordinary dwellings, such as a house. Specifically, the Disinfection Device 100 can be installed in wet areas, such as toilets, kitchens, sinks, drainpipes, etc. Alternatively, the Disinfection Device 100 can be installed in locations prone to condensation, such as under floors, in ceiling cavities, window frames, etc. Furthermore, the Disinfection Device 100 can be installed in poorly ventilated shoe closets, wardrobes, toilets, etc.

[0163] Furthermore, the disinfection device 100 can be installed in electrical appliances, for example. In particular, the disinfection device 100 can be installed in dishwashers, washing machines, refrigerators, rice cookers, alkaline ion water purifiers, vacuum cleaners, or air conditioning units such as fans, dehumidifiers, dryers, humidifiers, etc.

[0164] Furthermore, the Disinfection Device 100 can also be used in agriculture, fishing, and livestock farming. Specifically, it can be installed in plastic greenhouses, food processing plants, slaughterhouses, fish distribution centers, wholesale markets, and so on. For example, food processing plants include facilities for processing various food products, such as canned goods, cut vegetables, powdered foods, alcoholic beverages, frozen foods, and so forth. The Disinfection Device 100 can also be used in plant nurseries that utilize artificial light, in protected horticulture that employs both artificial and sunlight, as outdoor lighting for open-field cultivation, and so forth.

[0165] Furthermore, the disinfection device 100 can also be used in the industrial sector. For example, the disinfection device 100 can be installed in a drainage system, etc., of semiconductor wafer manufacturing plants, etc.

[0166] Furthermore, the Disinfection Device 100 can be installed in various buildings of different institutions, such as office buildings, hospitals, nursing homes, school meal centers, schools, etc. It can also be used in restaurants, such as cafes, restaurants, bars, etc., or in retail stores, such as flower shops, pet stores, etc. Additionally, the Disinfection Device 100 can be installed in the food departments of supermarkets or department stores. In particular, it can be used near the fresh fish department or refrigeration units, including the ceiling.

[0167] It should be noted that in the same way, the disinfection device 200 according to embodiment 2 and the disinfection device 100, which uses a photocatalyst 311, according to embodiment 3, can also be applied to all environments that may come into contact with water or steam, as has been illustrated above by way of example.

[0168] Furthermore, in each of the foregoing embodiments, structural components, such as the control circuit 140, the memory 160, and the switch 170, can be formed using special hardware or implemented by executing software programs suitable for the respective structural components. Each of the structural components can be implemented by a program-executing component, such as a central processing unit (CPU) or a processor, which reads and executes a software program recorded on a storage medium, such as a hard disk or semiconductor memory.

[0169] It should be noted that the present invention can be implemented not only as a disinfection device, but also as a program comprising as steps the operations carried out by the respective structural components of the disinfection device, and a computer-readable recording medium on which such a program is recorded, such as a digital multi-purpose disc (DVD), etc.

[0170] In particular, the generic or specific aspects described above can be implemented as a system, a device, an integrated circuit, a computer program, and a computer-readable recording medium, and can be implemented by any combination of a system, a device, an integrated circuit, a computer program, and a recording medium.

[0171] The present invention encompasses forms obtained through various modifications of the embodiment that can be made by a person skilled in the art, as well as forms realized by any combination of structural components and functions in the embodiment that are within the scope of the essence of the present invention. [List of reference symbols] 100, 200 disinfection device 110, 210 Light source 130 Optical component (optical filter) 311 Photocatalyst

Claims

[1] Disinfection procedures, including: Irradiation of a fungus and a bacterium with light comprising violet light with a light emission peak having (i) a half-width of at most 20 nm and (ii) a peak wavelength greater than 380 nm and less than 400 nm, wherein the light: does not include UV-A light with a light emission peak having a peak wavelength that is contained within an entire range from 350 nm to 380 nm, inclusive, and does not contain a light emission peak with a light emission intensity greater than the light emission intensity of the light emission peak of the violet light in a wavelength range from 350 nm to 450 nm, inclusive. [2] Disinfection method according to claim 1, wherein the light further comprises UV-B light having a light emission peak with a peak wavelength that is contained in a range from 280 nm to 350 nm, inclusive. [3] Disinfection method according to claim 1 or 2, wherein irradiation with violet light and non-irradiation are repeated during irradiation. [4] Disinfection method according to any one of claims 1 to 3, wherein the fungus is one of Cladosporium and Rhodotorula. [5] Disinfection method according to any one of claims 1 to 3, wherein the bacterium is Pseudomonas aeruginosa. [6] Disinfection method according to one of claims 1 to 5, wherein, during irradiation, a photocatalyst arranged adjacent to one of the fungus and the bacterium is additionally irradiated with light. [7] Disinfection method according to claim 6, wherein the photocatalyst is tungsten oxide. [8] Disinfection device, comprising: a light source that illuminates a fungus and a bacterium with light having a light emission peak with (i) a half-width of at most 20 nm and (ii) a peak wavelength greater than 380 nm and less than 400 nm, wherein the light: does not include UV-A light with a light emission peak having a peak wavelength that is contained within an entire range from 350 nm to 380 nm, inclusive, and does not contain a light emission peak with a light emission intensity greater than the light emission intensity of the light emission peak of the violet light in a wavelength range from 350 nm to 450 nm, inclusive. [9] Disinfection device according to claim 8, further comprising: an optical filter that is positioned between the light source and the fungus and bacterium, and removes wavelength components from the light in a range from 350 nm to 380 nm, inclusive.

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