JP2022087812A - Inactivation device and inactivation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively and more appropriately conduct inactivation of microbes and/or viruses, by using ultraviolet light of a wavelength range suppressing an adverse effect on a human body.

SOLUTION: An inactivation device includes: a light source part configured to emit ultraviolet light with a center wavelength in a wavelength band of 190 to 235 nm; a detection part configured to detect whether a person is present in a target space; and a control part configured to control a lighting state of the light source part. The control part is configured to conduct ultraviolet light irradiation for a prescribed period of time while the detection part detects no presence of the person, after an elapse of the prescribed period of time make the light source part suspend the ultraviolet light irradiation and thereafter make the light source part continue the suspension of the ultraviolet light irradiation at least until the detection part detects a presence of the person.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to an inactivating device and an inactivating method for inactivating harmful microorganisms and viruses.

Conventionally, in order to prevent the spread of infectious diseases caused by harmful microorganisms (bacteria, molds, etc.) and viruses, microorganisms and viruses floating in space, and microorganisms attached to various places such as floors, walls, and surfaces of objects. And viruses are inactivated by irradiating them with ultraviolet rays.
For example, Patent Document 1 discloses an indoor sterilizer that is attached to an upper part of a room and irradiates ultraviolet rays horizontally, diagonally downward, and downward in the room.

The indoor sterilizer described in Patent Document 1 includes a horizontal irradiation unit and a downward irradiation unit, and can irradiate ultraviolet rays in the horizontal direction, diagonally downward, and downward. The ultraviolet rays of 254 nm exemplified in Patent Document 1 are generally considered to be harmful to the human body. Therefore, when there is a person in the room, it is not possible to irradiate the ultraviolet rays diagonally downward and downward. When irradiating a person while in the room, the irradiation was limited to a range where the person was not exposed to ultraviolet rays, such as irradiating horizontally near the ceiling.

Patent Document 2 discloses a technique of sterilizing a room by irradiating the room with ultraviolet rays from a germicidal lamp that irradiates ultraviolet rays. However, when the presence of a person is detected, the irradiation of ultraviolet rays is stopped. Is described. That is, in the prior art, it is premised that the irradiation of ultraviolet rays is stopped when a person enters the area requiring sterilization.

Further, Patent Document 3 discloses a technique for inactivating bacteria while substantially avoiding harm to cells of the human or animal body. In this Patent Document 3, microorganisms in food, air and purified water can be decomposed by using ultraviolet sterilization irradiation, and UVB or UVC ultraviolet rays are typically used, and these ultraviolet rays are used for humans and other organisms. The points that are dangerous are described. Furthermore, ultraviolet rays with a wavelength of more than 240 nm cause damage to DNA in human cell nuclei, and ultraviolet rays have different cell penetrating power depending on the wavelength, and the shorter the wavelength, the smaller the radiation penetrating power, which eliminates the harmful effects on human cells. The point, is described. Further, as a specific example, it has been shown that ultraviolet rays having a wavelength of 200 nm to 230 nm are used to selectively inactivate microorganisms and viruses without damaging human or animal cells.

Japanese Unexamined Patent Publication No. 2018-130131 Japanese Unexamined Patent Publication No. 10-248759 Special Table 2018-517488 Gazette

Based on Patent Document 3, the purpose is to more efficiently inactivate microorganisms and viruses by using ultraviolet rays having a wavelength band shorter than 240 nm of 190 nm to 235 nm as ultraviolet rays whose harmfulness to humans and animals is suppressed. did.

In order to solve the above problems, one aspect of the inactivating device according to the present invention is a light source unit that emits ultraviolet rays having a central wavelength in the wavelength band of 190 nm to 235 nm, and whether or not a human exists in the target space. A detection unit for detecting and a control unit for controlling the lighting state of the light source unit are provided. After a lapse of time, the light source unit is stopped from irradiating ultraviolet rays, and then the light source unit is continuously stopped from irradiating ultraviolet rays until at least the detection unit detects the presence of a human.

The "fixed time" here is set to a time that allows microorganisms and viruses existing in the target space to be sufficiently inactivated, and specifically, the inactivation rate is 90 in the selected lighting operation mode. % Or more, more preferably 99% or more, and more preferably 99.9% or more, and the time is set so that the ultraviolet rays can be irradiated. The amount of ultraviolet rays required for inactivation differs depending on the target microorganism or virus, and is appropriately changed depending on the type of target microorganism or virus.
As a result, unnecessary ultraviolet irradiation can be reduced by turning off the light after achieving the required amount of ultraviolet irradiation during the unmanned period in which the detection unit does not detect the presence of a human. In particular, during the unmanned period, bacteria and viruses are not newly introduced into the target space through humans, so that the inactivated state in the target space is not aggravated.

In addition, when inactivating bacteria using ultraviolet rays, it is necessary to consider "light recovery of bacteria". Some bacteria have the effect of repairing DNA damage by being irradiated with light (including the visible light range) with a wavelength of 300 nm to 500 nm, even after the DNA has been damaged by ultraviolet irradiation. .. This is due to the action of a photolyase (for example, FAD (flavin adenine dinucleotide)) possessed by bacteria, and this phenomenon is called "photolyase of bacteria".
However, it was confirmed that when the bacteria were inactivated by irradiation with ultraviolet rays having a central wavelength in the wavelength range of 190 nm to 235 nm, for example, ultraviolet rays having a wavelength of 222 nm, the bacteria were not recovered even if visible light was irradiated after the ultraviolet irradiation. Was done. It is considered that this action is due to the fact that ultraviolet rays having a wavelength band shorter than 240 nm are effectively absorbed by proteins, which are components of cell membranes and enzymes possessed by bacteria and viruses. More specifically, ultraviolet light in the wavelength band shorter than 240 nm is absorbed by the human skin surface (for example, the stratum corneum), is difficult to penetrate into the skin, and is highly safe for the skin, but bacteria and viruses are human. It is physically much smaller than cells, and ultraviolet light can easily reach the inside even in the wavelength band shorter than 240 nm. Therefore, it is considered that it effectively acts on cells constituting bacteria and viruses, particularly cell membranes and enzymes containing protein components, and enhances the effect of suppressing functions such as photorecovery of bacteria.

That is, if the bacteria are inactivated by ultraviolet rays having a wavelength of 190 nm to 235 nm within the unmanned period, even if the irradiation of the ultraviolet rays is stopped thereafter, the survival amount of the bacteria will not be restored by the irradiation with visible light.
Therefore, after the inactivation in the target space is executed by the irradiation of ultraviolet rays for a certain period of time, it becomes easy to maintain the inactivated state even if the irradiation of ultraviolet rays is stopped, and the power consumption of the inactivating device can be suppressed. can. In addition, the members (for example, wallpaper, furniture, etc.) existing in the target space are not excessively irradiated with ultraviolet rays.

Further, when the detection unit detects the presence of a human after the detection unit stops irradiating the light source unit with ultraviolet rays after a certain period of time has passed during which the detection unit does not detect the presence of a human. , The ultraviolet irradiation may be started.
Even after the required amount of ultraviolet rays have been irradiated into the target space during the period when the presence of humans is not detected, if a new human enters the target space, new microorganisms or viruses will be introduced through the human. May be brought in. Since this inhibits the inactivated state, UV irradiation is performed when the presence of a human is detected. As a result, the inactivation level in the target space can be kept high.

Further, when the detection unit detects the presence of a human after the detection unit stops irradiating the light source unit with ultraviolet rays after a certain period of time has passed during which the detection unit does not detect the presence of a human. , The ultraviolet irradiation may be controlled to continue to be stopped, and the ultraviolet irradiation may be started when the detection unit no longer detects the presence of a human being.
In this case as well, it is assumed that there is a possibility that new microorganisms and viruses will be introduced through humans when a new human enters the target space after UV irradiation is performed for a certain period of time during the period when the presence of humans is not detected. However, when the amount of ultraviolet rays to humans is close to the upper limit, the microorganisms left in the target space at the timing when humans are absent again without directly irradiating humans with ultraviolet rays. It is possible to irradiate the virus with ultraviolet rays, and it is possible to realize safer starting control assuming the allowable limit value of the amount of ultraviolet rays to humans.

Further, one aspect of the inactivation method according to the present invention is an inactivation method for controlling the lighting state of a light source unit that emits ultraviolet rays having a central wavelength in the wavelength band of 190 nm to 235 nm, and a human being in the target space. After irradiating with ultraviolet rays for a certain period of time during the step of detecting the presence or absence and the period during which the presence of the human is not detected, the light source unit is stopped from irradiating the ultraviolet rays, and then at least until the presence of the human is detected. In the meantime, the light source unit includes a step of continuing to stop the irradiation of ultraviolet rays.

If the bacteria are inactivated by ultraviolet rays having a wavelength of 190 nm to 235 nm within the unmanned period, the survival amount of the bacteria will not be restored by the visible light irradiation even if the irradiation of the ultraviolet rays is stopped thereafter.
Therefore, after the inactivation in the target space is executed by the irradiation of ultraviolet rays for a certain period of time, it becomes easy to maintain the inactivated state even if the irradiation of ultraviolet rays is stopped, and the power consumption of the inactivating device can be suppressed. can. In addition, the members (for example, wallpaper, furniture, etc.) existing in the target space are not excessively irradiated with ultraviolet rays.

According to one aspect of the present invention, inactivation of microorganisms and / or viruses using ultraviolet rays in a wavelength range in which adverse effects on the human body are suppressed can be effectively and more appropriately performed.

It is an external image figure of the inactivated device of this embodiment. It is explanatory drawing about the operation example of this embodiment. This is the result of a light recovery experiment of bacteria by irradiation with ultraviolet rays having a wavelength of 254 nm. This is the result of a light recovery experiment of bacteria by irradiation with ultraviolet rays having a wavelength of 222 nm. It is explanatory drawing about the operation example of this embodiment. It is explanatory drawing about the operation example of this embodiment. It is explanatory drawing about the operation example of this embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an external image diagram of the inactivating device 100 in the present embodiment.
The inactivating device 100 is a device that irradiates ultraviolet rays in a space where humans and animals exist to inactivate microorganisms and viruses existing in the space and the surface of an object in the space.
Here, the above space is, for example, a space in a facility such as an office, a commercial facility, a medical facility, a station facility, a school, a government office, a theater, a hotel, a restaurant, a car, a train, a bus, a taxi, an airplane, a ship, etc. Includes space within the vehicle. The space may be a closed space such as a hospital room, a conference room, a toilet, or an elevator, or may be an unclosed space.

The inactivating device 100 irradiates the target space with ultraviolet rays having a wavelength of 190 to 235 nm (more preferably, ultraviolet rays having a wavelength range of 200 nm to 230 nm), which have little adverse effect on human or animal cells, in the target space. It inactivates harmful microorganisms and viruses that exist on the surface and space of objects. Here, the above-mentioned object includes a human body, an animal, and an object. Further, the target space to be irradiated with ultraviolet rays is not limited to the space where people and animals actually exist, but includes the space where people and animals enter and exit and where there are no people or animals.
The term "inactivation" as used herein refers to killing microorganisms and viruses (or losing infectivity and toxicity).

As shown in FIG. 1, the inactivating device 100 includes a light source unit that generates ultraviolet rays, a control unit 16 that controls lighting of the light source unit, and a housing 11 that houses the light source unit and the control unit 16. The housing 11 is formed with a light emitting surface 12 that emits ultraviolet rays. Specifically, an opening 11a that serves as a light emitting window that radiates ultraviolet rays is formed. A window member made of, for example, quartz glass is provided in the opening 11a, and ultraviolet rays are radiated from the window member. Further, the opening 11a may be provided with an optical filter or the like that blocks light in an unnecessary wavelength band.
An excimer lamp 20 is housed inside the housing 11 as an ultraviolet light source. The excimer lamp 20 can be, for example, a KrCl excimer lamp that emits ultraviolet rays having a center wavelength of 222 nm. The ultraviolet light source is not limited to the KrCl excimer lamp, and may be any light source that radiates ultraviolet rays in the wavelength range of 190 nm to 235 nm. The housing 11 and the ultraviolet light source (excimer lamp 20) form a light source unit.

In UV radiation, the penetrating power of cells differs depending on the wavelength, and the shorter the wavelength, the smaller the penetrating power. For example, UV radiation with a short wavelength of about 200 nm passes through water very efficiently, but is highly absorbed by the outer part (cytoplasm) of human cells and is sufficient to reach the cell nucleus containing DNA sensitive to UV radiation. May not have enough energy. Therefore, the above-mentioned short wavelength UV radiation has little adverse effect on human cells. On the other hand, ultraviolet rays having a wavelength of more than 240 nm can damage DNA in human cell nuclei. Further, it is known that ultraviolet rays having a wavelength of less than 190 nm generate ozone.
Therefore, in the present embodiment, as the ultraviolet light source, an ultraviolet light source that radiates ultraviolet rays in a wavelength range of 190 nm to 235 nm, which has little adverse effect on the human body and has an inactivating effect, and does not substantially radiate other UVCs is used. Further, as a wavelength band with higher safety, an ultraviolet light source having a peak wavelength in the wavelength range of 200 nm to 230 nm may be used.

The excimer lamp 20 includes a straight tubular discharge container 21 in which both ends are hermetically sealed. The discharge container 21 can be made of, for example, quartz glass. Further, the inside of the discharge container 21 is filled with a rare gas and a halogen as light emitting gas. In this embodiment, krypton chloride (KrCl) gas is used as the luminescent gas. In this case, the peak wavelength of the obtained synchrotron radiation is 222 nm.
The luminescent gas is not limited to the above. For example, krypton bromide (KrBr) gas or the like can be used as the luminescent gas. In the case of a KrBr excimer lamp, the peak wavelength of the obtained synchrotron radiation is 207 nm.
Further, in FIG. 1, the inactivating device 100 includes a plurality of (three) discharge containers 21, but the number of discharge containers 21 is not particularly limited.

A pair of electrodes (first electrode 22 and second electrode 23) are arranged so as to abut on the outer surface of the discharge container 21. The first electrode 22 and the second electrode 23 are arranged on the side surface (the surface in the −Z direction) opposite to the light extraction surface of the discharge container 21 so as to be separated from each other in the tube axis direction (Y direction) of the discharge container 21. Has been done.
The discharge container 21 is arranged so as to straddle the two electrodes 22 and 22 while in contact with each other. Specifically, a concave groove is formed in the two electrodes 22 and 23, and the discharge container 21 is fitted in the concave groove of the electrodes 22 and 23.

Of the pair of electrodes, one electrode (for example, the first electrode 22) is the high pressure side electrode, and the other electrode (for example, the second electrode 23) is the low pressure side electrode (ground electrode). By applying a high frequency voltage between the first electrode 22 and the second electrode 23, the lamp is turned on.

The light extraction surface of the excimer lamp 20 is arranged so as to face the light emission window. Therefore, the light emitted from the excimer lamp 20 is emitted from the light emitting surface 12 of the inactivating device 100 through the light emitting window.
Here, the electrodes 22 and 23 may be made of a metal member having a reflectivity with respect to the light emitted from the excimer lamp 21. In this case, the light radiated from the discharge container 21 in the −Z direction can be reflected and traveled in the + Z direction.

As described above, an optical filter can be provided in the opening 11a serving as the light emitting window. The optical filter is, for example, a wavelength selection filter that transmits light having a wavelength range of 190 nm to 235 nm (more preferably light having a wavelength range of 200 nm to 230 nm) and cuts a UVC wavelength band having a wavelength range of 236 nm to 280 nm. Can be. Specifically, each ultraviolet illuminance having a wavelength of 236 nm to 280 nm is reduced to 1% or less with respect to the ultraviolet illuminance of the peak wavelength in the wavelength band of 190 nm to 235 nm. As the wavelength selection filter, for example, an optical filter having a dielectric multilayer film composed of _two layers of HfO and _two layers of SiO can be used.

As the wavelength selection filter, an optical filter having a dielectric multilayer film composed of _two layers of SiO and _three layers of _Al2O can also be used. By providing the optical filter in the light emitting window in this way, even if the excimer lamp 20 emits light harmful to humans, it is more reliable that the light leaks to the outside of the housing 11. Can be suppressed to.

Further, the inactivating device 100 is provided with a detection unit 31 for detecting the presence of a human being in the target space. The detection unit 31 may be integrally formed with the inactivating device 100, or may be one that detects by receiving a signal from the outside. As one embodiment, a motion sensor can be used. The motion sensor can be, for example, a pyroelectric infrared sensor that detects a change in heat (infrared ray) generated from a human body or the like. As another embodiment, the occupied time and the non-occupied time in the target space that is supposed to be used by a person may be detected.

Further, as shown in FIG. 1, the inactivating device 100 includes a power supply unit 15 and a control unit 16.
The power supply unit 15 includes a power supply member such as an inverter to which electric power is supplied from the power source, and a cooling member such as a heat sink for cooling the power supply member. Further, the control unit 16 controls the lighting of the excimer lamp 20 constituting the light source unit.

FIG. 2 is an explanatory diagram showing one aspect of the lighting operation according to the present invention.
The control unit 16 detects the presence of a human in the target space based on the signal from the detection unit 31 (here, also referred to as a manned period) and a period in which the presence of a human is not detected in the target space (here, also referred to as a manned period). In the unmanned period), the first lighting operation is executed in the manned period and the second lighting operation is executed in the unmanned period so that the average illuminance of the ultraviolet rays radiated from the light source unit is different. As shown in FIG. 2, when ultraviolet rays are continuously emitted, the average illuminance is a value obtained by dividing the integrated value of the illuminance within a predetermined period by the predetermined period.

In the first lighting operation, lighting with a relatively low average illuminance of ultraviolet rays is executed, and in the second lighting operation, lighting is controlled so that lighting with a relatively high average illuminance of ultraviolet rays is executed. For example, the lighting state may be controlled so that the average illuminance in the first lighting operation is set to 1 μW / cm ² or less and the average illuminance in the second lighting operation exceeds 1 μW / cm ² .
According to ACGIH (American Conference of Governmental Industrial Hygienists) and JIS Z 8812 (measurement method of harmful ultraviolet radiation), the amount of ultraviolet rays per day (8 hours) on the human body is per wavelength. The permissible limit value (TLV: Threshold Limit Value) is set in the above, and it is required to determine the illuminance and the irradiation amount of ultraviolet rays to be irradiated per predetermined time to the extent that the permissible limit value is not exceeded. This permissible limit value may be revised in the future, but for example, the average illuminance in the first lighting operation performed during the manned period is the above permissible limit value even if the ultraviolet irradiation amount is continuously irradiated for 8 hours. It may be set to a value that does not exceed.

In the present embodiment, as shown in FIG. 2, when the manned period is switched to the unmanned period at time t1, the first lighting operation is switched to the second lighting operation, and the average illuminance is switched from low illuminance to high illuminance. After that, when the unmanned period is switched to the manned period at time t2, the second lighting operation is switched to the first lighting operation, and the average illuminance is switched from high illuminance to low illuminance.
Therefore, during the period when no one is present in the target space, the second lighting operation with a higher average illuminance of ultraviolet rays is executed, so that the microorganisms and viruses in the target space can be inactivated more effectively. can. Further, even during the period in which the presence of a human being is detected in the target space, by executing the first lighting operation, it is possible to irradiate a predetermined ultraviolet ray and inactivate microorganisms and viruses.

Further, as shown in FIG. 2, the second lighting operation may be controlled to stop (turn off) the operation after the end of the operation for a predetermined fixed time. That is, as shown in FIG. 2, after switching from the manned period to the unmanned period at time t3, the irradiation of ultraviolet rays may be stopped at time t4 when a certain time has elapsed.
In the unmanned period, inactivation in the space is achieved if necessary and sufficient ultraviolet irradiation is performed in the target space. Therefore, when it is difficult to assume that a new microorganism or virus will enter through humans, it is possible to suppress excessive ultraviolet irradiation into the target space by stopping (turning off) the lighting operation. As a result, power consumption can be suppressed. Further, the light emitting operation time of the light source unit can be reduced, and the service life of the inactivating device 100 can be extended.

Further, the stoppage of the second lighting operation will be described in detail in the case where the inactivation of bacteria is assumed. When inactivating bacteria using ultraviolet rays, it is necessary to consider "light recovery of bacteria". Some bacteria have the effect of repairing DNA damage by being irradiated with light (including the visible light range) with a wavelength of 300 nm to 500 nm, even after the DNA has been damaged by ultraviolet irradiation. .. This is due to the action of a photolyase (for example, FAD (flavin adenine dinucleotide)) possessed by bacteria, and this phenomenon is called "photolyase of bacteria".

However, it was confirmed that when the bacteria were inactivated by irradiation with ultraviolet rays having a central wavelength in the wavelength range of 190 nm to 235 nm, for example, ultraviolet rays having a wavelength of 222 nm, the bacteria were not recovered even if visible light was irradiated after the ultraviolet irradiation. Was done. That is, if the bacteria are inactivated by ultraviolet rays having a wavelength of 190 nm to 235 nm within the unmanned period, even if the irradiation of the ultraviolet rays is stopped thereafter, the survival amount of the bacteria will not be restored by the irradiation with visible light.
Therefore, after the inactivation in the target space is executed by the irradiation of ultraviolet rays for a certain period of time, it becomes easy to maintain the inactivated state even if the irradiation of ultraviolet rays is stopped, and the power consumption of the inactivating device 100 can be suppressed. Can be done. In addition, the members (for example, wallpaper, furniture, etc.) existing in the target space are not excessively irradiated with ultraviolet rays. This is an effect that cannot be realized with a low-pressure mercury lamp (main wavelength of 254 nm) known as a germicidal lamp.

3 and 4 show the verification results of verifying the inactivating effect of bacteria with a KrCl excimer lamp having a wavelength of 200 nm to 230 nm (main wavelength is 222 nm) and a low-pressure mercury lamp having a main wavelength of 254 nm.

FIG. 3 shows the results of a light recovery experiment of bacteria by ultraviolet irradiation using a low-pressure mercury lamp having a main wavelength of 254 nm, and FIG. 4 shows the results of a light recovery experiment of bacteria by ultraviolet irradiation having a wavelength of 200 nm to 230 nm (main wavelength 222 nm). Is. Here, the bacterium to be inactivated was Staphylococcus aureus, and UV irradiation was performed in an environment where visible light including light having a wavelength of 300 nm to 500 nm was irradiated, and the change in the survival rate of the bacterium after UV irradiation was confirmed. .. Staphylococcus aureus has a photolyase and is a bacterium that causes photolyase of the bacterium when irradiated with visible light.

In FIGS. 3 and 4, the horizontal axis is the elapsed time (h), and the vertical axis is the log survival rate of the bacterium. In FIGS. 3 and 4, the experimental results a to d show changes in the survival rate of the bacteria when the ultraviolet irradiation dose is 0 mJ / cm ² , 5 mJ / cm ² , 10 mJ / cm ² , and 15 mJ / cm ² . .. Here, the irradiation time of ultraviolet rays was set to 30 minutes, and then the irradiation of ultraviolet rays was stopped, and the change in the survival rate of the bacteria was confirmed.

As shown in FIG. 3, the survival rate of the fungus increases with the passage of time. That is, in an environment where visible light is irradiated, the bacteria are light-recovered after being irradiated with ultraviolet rays having a wavelength of 254 nm. Specifically, the survival number of the bacterium is significantly recovered in about 1 to 2 hours by irradiation with visible light.
On the other hand, as shown in FIG. 4, when ultraviolet irradiation having a wavelength of 222 nm is performed, recovery of the bacteria is not observed even if visible light is irradiated. That is, the photorecovery of the fungus is inhibited.

Bacteria in which photorecovery is inhibited are inactivated without proliferation because DNA damage remains. Irradiation with ultraviolet rays having a wavelength of 222 nm can effectively reduce the recovery and growth of bacteria. Therefore, an inactivation system that irradiates ultraviolet light with a wavelength of 222 nm works particularly effectively in an environment in which light recovery of bacteria is easy, specifically, in an environment in which visible light including light having a wavelength of 300 nm to 500 nm is irradiated. ..

As described above, the inactivating device 100 according to the present invention changes and controls the lighting operation between the manned period and the unmanned period, and the lighting operation during the unmanned period is a fixed time for achieving sufficient ultraviolet irradiation in the target space. By turning off the lights after the lapse of time, more efficient inactivation can be realized.
Further, the time (constant time) in which the second lighting operation time is continued can be calculated as follows, for example.

Let E be the amount of ultraviolet rays (mJ / cm ² ) that can inactivate 90% or more, more preferably 99% or more of the microorganisms and viruses to be inactivated, and the illuminance in the region with a distance of 50 cm from the light radiation surface 12. Is I ₅₀ , and the distance from the light irradiation surface 12 to the object to be inactivated (the object to be inactivated) is h, and the irradiation required for sufficient inactivation is based on the following calculation formula (1). Time H may be calculated.
Required irradiation time H = E / (0.6 x I ₅₀ x (50 / h) ² ) ... (1)
In the above equation (1), I ₅₀ × (50 / h) ² is the illuminance I _h of ultraviolet rays on a surface separated from the light emitting surface 12 by a distance h. That is, the irradiation time H can inactivate the inactivation target in a region (60% illuminance area) where the ultraviolet illuminance is 60% of the maximum illuminance of ultraviolet rays on a surface separated from the light emitting surface 12 by a distance h. Time is set.

For example, the illuminance in a region where the distance from the light emitting surface 12 is 50 cm is 53.6 μW / cm ² , and the amount of ultraviolet rays required for 99% inactivation of a predetermined virus is 2 mJ / cm ² . When the distance h from the irradiation surface 12 to the object is 200 cm, the required irradiation time H is 995 seconds (about 17 minutes). Further, assuming that the second lighting operation is an intermittent operation in which the lighting time and the extinguishing time are alternately repeated, when the lighting time is 15 seconds and the extinguishing time is 30 seconds, the required driving of the second lighting operation is performed. The time can be estimated to be 0.8 hours. By such calculation, the time (constant time) in which the second lighting operation time is continued may be determined so that the driving time is 0.8 hours or more. Here, for example, a fixed time can be set as one hour. If the inactivation rate is set to a higher value (for example, 99.9%), it is necessary to set a longer width for a certain period of time.

Further, as shown in FIG. 2, if the presence of a human being is detected by the detection unit 31 after the second lighting operation is stopped, the first lighting operation may be executed. That is, as shown in FIG. 2, if the presence of a human being is detected at time t5 after the second lighting operation is stopped at time t4, the first lighting operation may be executed at this time t5.
If the detection unit 31 detects the presence of a human after the second lighting operation is stopped, the detection unit 31 waits until the presence of a human is no longer detected, and the detection unit 31 waits until the presence of a human is detected. When it is no longer detected, the second lighting operation may be executed. That is, as shown in FIG. 5, when the presence of a human being is detected at time t5 after the second lighting operation is stopped at time t4, the first lighting operation is not executed at this time t5 and thereafter. When the presence of a human is no longer detected at time t6, the second lighting operation may be executed.

Here, either or both of the first lighting operation and the second lighting operation may be performed periodically, and as shown in FIG. 6, the lighting operation and the extinguishing operation are alternately performed. It may perform an intermittent operation that is repeated (a lighting time in which the light source unit is turned on and an extinguishing time in which the light source unit is turned off are repeated alternately).
FIG. 6 is an explanatory diagram showing one aspect of the lighting operation according to the present invention, and shows one aspect in which the first lighting operation and the second lighting operation each perform an intermittent operation. A period for detecting the presence of a human in the target space based on the signal from the detection unit 31 (also referred to as a manned period here) and a period during which the presence of a human is not detected in the target space (here, also referred to as an unmanned period). ), The first lighting operation is executed in the manned period and the second lighting operation is executed in the unmanned period so that the average illuminance of the ultraviolet rays radiated from the light source unit is different.

The average illuminance here may be determined as the average illuminance per cycle.
That is, when the periodic intermittent operation is performed as shown in FIG. 6, the average illuminance is the illuminance × duty ratio. Here, the duty ratio is the ratio of the lighting time to the total of the lighting time and the extinguishing time, and is a value expressed by the lighting time / (lighting time + extinguishing time).

In the first lighting operation, a lighting operation in which the average illuminance of ultraviolet rays is relatively low is executed, and in the second lighting operation, a lighting operation in which the average illuminance of ultraviolet rays is relatively high is executed. For example, the lighting state may be controlled so that the average illuminance in the first lighting operation is set to 1 μW / cm ² or less and the average illuminance in the second lighting operation exceeds 1 μW / cm ² .

As shown in FIG. 6, when the manned period is switched to the unmanned period at time t11, the first lighting operation is switched to the second lighting operation, and the average illuminance is switched from low illuminance to high illuminance. Here, the average illuminance is switched from low illuminance to high illuminance by shortening the turn-off time in the periodic on / off cycle. After that, when the unmanned period is switched to the manned period at time t12, the second lighting operation is switched to the first lighting operation, and the average illuminance is switched from high illuminance to low illuminance. That is, the extinguishing time becomes long.
Therefore, as in the embodiment shown in FIG. 2, during the period when no person is present in the target space, the second lighting operation having a higher average illuminance of the ultraviolet rays is executed, so that the second lighting operation is more effectively performed in the target space. It can inactivate microorganisms and viruses. Further, even during the period in which the presence of a human being is detected in the target space, by executing the first lighting operation, it is possible to irradiate a predetermined ultraviolet ray and inactivate microorganisms and viruses.

Further, as in the embodiment shown in FIG. 2, the second lighting operation may be controlled so as to stop (turn off) the operation after the end of the operation for a predetermined fixed time. That is, as shown in FIG. 6, after switching from the manned period to the unmanned period at time t13, the irradiation of ultraviolet rays may be stopped at time t14 when a certain time has elapsed. Here, the fixed time is the time during which the irradiation time H (sec) calculated by the above equation (1) is executed.
In the unmanned period, inactivation in the space is achieved if necessary and sufficient ultraviolet irradiation is performed in the target space. Therefore, when it is difficult to assume that a new microorganism or virus will enter through humans, it is possible to suppress excessive ultraviolet irradiation into the target space by stopping (turning off) the lighting operation. As a result, power consumption can be suppressed. Further, the light emitting operation time of the light source unit can be reduced, and the service life of the inactivating device 100 can be extended.

Further, as shown in FIG. 6, if the presence of a human being is detected by the detection unit 31 after the second lighting operation is stopped, the first lighting operation may be executed. That is, as shown in FIG. 6, if the presence of a human being is detected at time t15 after the second lighting operation is stopped at time t14, the first lighting operation may be executed at this time t15.

Further, when the detection unit 31 detects the presence of a human and switches to the first lighting operation, the extinguishing time may be started first, and then the lighting time may be started. That is, as shown in FIG. 7, when the presence of a human being is detected at time t15 after the second lighting operation is stopped at time t14, the time after waiting for the extinguishing time in the periodic lighting / extinguishing cycle. At t16, the lighting time may be started.
If the lighting operation is started, the lighting time may be relatively long when the presence / absence of a human fluctuates drastically. By starting from the extinguishing time, it is easy to maintain the lighting time at an appropriate value.

In addition, the control of the average illuminance of ultraviolet rays in the first lighting operation and the second lighting operation changes the ratio of the lighting time and the extinguishing time of the light source unit, adjusts the voltage applied to the light emitter provided in the light source unit, and controls the light source unit. It can be realized by various control methods such as adjustment of the frequency of the voltage applied to the light source provided in the above.
In the first lighting operation and the second lighting operation, when an intermittent operation in which the lighting time and the extinguishing time are alternately repeated is performed, in the above embodiment, the lighting time and the extinguishing time of the light source unit are adjusted by adjusting the extinguishing time. Although the case of changing the ratio of the lighting time has been described, the lighting time may be adjusted, or both the lighting time and the extinguishing time may be adjusted.

In this embodiment, it is proposed to control the detection unit 31 to stop the second lighting operation after a certain period of time during which the presence of a human is not detected has elapsed. This is because it is easy to maintain an inactivated state by using ultraviolet rays in a wavelength band that can suppress the light recovery of bacteria. However, even if a person remains absent after controlling to stop the second lighting operation, the relighting may be performed after a lapse of a predetermined time.
There is a high possibility that new bacteria and viruses will be brought into the target space via humans, but it is also possible that bacteria and viruses may flow into the space from the outside without human intervention. Assuming such a case, if the extinguishing time continues for a long time, additional control may be executed so as to maintain the inactivation level in the target space by executing the lighting operation again.

Further, based on the above findings, it is conceivable to adopt the following device configuration and inactivation method.
For example, a light source unit that radiates ultraviolet rays having a central wavelength in the wavelength band of 190 nm to 235 nm, a detection unit that detects whether or not a human is present in the target space, and a control unit that controls the lighting state of the light source unit. The control unit includes a second lighting operation that is executed during a period in which the detection unit does not detect the presence of a human, and the second lighting operation has a period in which the detection unit does not detect the presence of a human. The inactivating device may be characterized in that it is controlled to stop after a certain period of time has elapsed.

Further, in the above-mentioned inactivating device, the distance from the light emitting surface of the light source unit to the inactivating target is h, and the illuminance of ultraviolet rays on the surface separated by the distance h from the light emitting surface is I _h (mW / cm ² ). ), When the amount of ultraviolet rays required for inactivating the inactivated object is E (mJ / cm ² ), the fixed time is the time during which the irradiation time H (sec) calculated by the following formula is executed. It's okay.
H = E / (0.6 × I _h )

Alternatively, it is an inactivation method for controlling the lighting state of a light source unit that radiates ultraviolet rays having a central wavelength in the wavelength band of 190 nm to 235 nm, and is a step of detecting whether or not a human is present in the target space, and the detection. The second lighting operation includes a step of executing a second lighting operation during a period in which the detection unit does not detect the presence of a human, and the second lighting operation is stopped after a certain period of time in which the detection unit does not detect the presence of a human has elapsed. It may be an inactivation method, characterized in that it is controlled to do so.

Further, in the above-mentioned inactivation method, the distance from the light emitting surface of the light source unit to the inactivating target is h, and the illuminance of ultraviolet rays on the surface separated by the distance h from the light emitting surface is I _h (mW / cm2). When the amount of ultraviolet rays required for inactivating the inactivating target is E (mJ / cm2), the fixed time may be the time during which the irradiation time H (sec) calculated by the following formula is executed. ..
H = E / (0.6 × I _h )

In the above configuration, the second lighting operation during the period in which the presence of a human is not detected is controlled so that the detection unit stops after a certain period of time in which the presence of a human is not detected has elapsed.
The "fixed time" here is set to a time that allows microorganisms and viruses existing in the target space to be sufficiently inactivated, and specifically, the inactivation rate is 90 in the selected lighting operation mode. % Or more, more preferably 99% or more, and more preferably 99.9% or more, and the time is set so that the ultraviolet rays can be irradiated. The amount of ultraviolet rays required for inactivation differs depending on the target microorganism or virus, and is appropriately changed depending on the type of target microorganism or virus.
As a result, unnecessary ultraviolet irradiation can be reduced by turning off the light after achieving the required amount of ultraviolet irradiation during the unmanned period in which the detection unit does not detect the presence of a human. In particular, during the unmanned period, bacteria and viruses are not newly introduced into the target space through humans, so that the inactivated state in the target space is not aggravated.

Furthermore, as described above, ultraviolet rays having a central wavelength in the wavelength range of 190 to 235 nm have the effect of suppressing the function of "light recovery of bacteria", and therefore, after inactivation in the target space is executed by irradiation with ultraviolet rays for a certain period of time. Makes it easier to maintain the inactivated state even when the irradiation of ultraviolet rays is stopped. That is, inactivation can be promoted more effectively, and excessive irradiation of ultraviolet rays to members (for example, wallpaper, furniture, etc.) existing in the target space can be suppressed. As a result, the power consumption and the service life of the inactivated device can be suppressed.

In the above lighting operation, if the detection unit detects the presence of a human after the second lighting operation is stopped, it may be controlled to continue the stopped state. In this case, the second lighting operation is executed during the period when the presence of a human is not detected again. Further, the second lighting operation may be controlled to stop after a certain period of time has elapsed.

By continuing the second lighting operation for a certain period of time, even after the required amount of ultraviolet rays has been irradiated into the target space, if a new human enters the target space, a new human will enter the target space. Microorganisms and viruses may be introduced. Since this hinders the inactivated state, if the detection unit detects the presence of a human after the second lighting operation is stopped, the first lighting operation is executed again during the manned period. UV irradiation may be performed. As a result, the inactivation level in the target space can be kept high.

Alternatively, in the above lighting operation, when the detection unit detects the presence of a human after the second lighting operation is stopped, a lighting operation different from the first lighting operation and the second lighting operation is executed. You may do so. In this case, the second lighting operation is executed when the existence of a human is not detected again. Further, the second lighting operation may be controlled to stop after a certain period of time has elapsed.

According to the above aspect, inactivation of microorganisms and / or viruses using ultraviolet rays in a wavelength range in which adverse effects on the human body are suppressed can be effectively and more appropriately performed.

11 ... Housing, 12 ... Light radiation surface, 15 ... Power supply unit, 16 ... Control unit, 20 ... Ultraviolet light source, 21 ... Discharge container, 22 ... First electrode, 23 ... Second electrode, 31 ... Detection unit, 100 ... Ultraviolet irradiation device

Claims (4)

A light source unit that radiates ultraviolet rays having a central wavelength in the wavelength band of 190 nm to 235 nm, and
A detector that detects whether or not a human is present in the target space,
A control unit that controls the lighting state of the light source unit is provided.
The control unit
The detection unit irradiates ultraviolet rays for a certain period of time during a period when the presence of a human is not detected, and after the certain time elapses, the light source unit is stopped from irradiating with ultraviolet rays, and then at least the detection unit detects the presence of a human. An inactivating device characterized in that the light source unit is continuously stopped from irradiating ultraviolet rays until the light source unit is used. The control unit
If the detection unit detects the presence of a human after the light source unit has stopped irradiating the light source after a certain period of time during which the detection unit does not detect the presence of a human, the ultraviolet irradiation is started. The inactivating device according to claim 1, wherein the inactivating device is characterized by the above. The control unit
If the detection unit detects the presence of a human after the light source unit has stopped irradiating the light source after a certain period of time during which the detection unit does not detect the presence of a human, the ultraviolet irradiation is stopped. The inactivating device according to claim 1, wherein the inactivating device is controlled so as to continue, and when the detection unit stops detecting the presence of a human, the ultraviolet irradiation is started. It is an inactivating method for controlling the lighting state of a light source unit that radiates ultraviolet rays having a central wavelength in the wavelength band of 190 nm to 235 nm.
Steps to detect if there is a human in the target space,
After irradiating the light source with ultraviolet rays for a certain period of time during the period when the presence of humans is not detected, the light source portion is stopped from irradiating with ultraviolet rays, and then the light source portion is irradiated with ultraviolet rays at least until the presence of humans is detected. An inactivation method characterized by including, and a step to continue the outage.

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