Ultraviolet light irradiation system

Abstract

The purpose of the present invention is to provide: an ultraviolet light irradiation system capable of monitoring a cumulative irradiation amount of ultraviolet light within a predetermined time for each person; and a control method therefor.　An ultraviolet light irradiation system according to the present invention is characterized by comprising: an ultraviolet light source unit 11 that generates ultraviolet light; an irradiation unit 13 that irradiates an irradiation target area AR with the ultraviolet light; a portable ultraviolet light sensor 20 that is carried by a worker and measures a cumulative irradiation amount of the ultraviolet light irradiated from the irradiation unit 13 to the irradiation target area AR; and a control unit 15 that performs stop control for stopping irradiation of the ultraviolet light from the irradiation unit 13 when the cumulative irradiation amount for a predetermined time exceeds a prescribed value.

Description

UV Light Irradiation System

[0001] The present disclosure relates to an ultraviolet light irradiation system that irradiates an object at a distance with ultraviolet light via an optical transmission path such as an optical fiber.

[0002] For purposes such as preventing infectious diseases, there is an increasing demand for ultraviolet light irradiation systems that use ultraviolet light for sterilization or inactivation. One known method of sterilization or inactivation is an ultraviolet light irradiation system that uses an ultraviolet light source unit 11, an optical fiber 16, and an irradiation unit 13, as shown in Figure 1, and that directly irradiates a specific location with ultraviolet light without requiring a large-scale device (see, for example, Non-Patent Documents 1 and 2). By using this ultraviolet light irradiation system, it is possible to deliver ultraviolet light using an optical fiber to sterilize or inactivate even in places or situations where direct irradiation with ultraviolet light is difficult.

[0003] In ultraviolet light irradiation systems using optical fibers, there are also configurations in which a branching section 12 is arranged in the optical transmission path as shown in Figure 2 (ultraviolet light irradiation systems using branched optical fibers) in order to efficiently sterilize or inactivate multiple irradiation target areas AR.

[0004] NTT News Release (November 13, 2020), https: / / group.ntt / jp / newsrelease / 2020 / 11 / 13 / 201113b.html, retrieved August 21, 2023. Katsuhisa Taguchi et al., "Virus Infection Prevention Technology Using Ultraviolet Fiber Transmission," Institute of Electronics, Information and Communication Engineers, Communication Systems Study Group, October 27, 2022.

[0005] Ultraviolet light is harmful to the human body, and in ultraviolet light irradiation systems, it is necessary to control the cumulative amount of irradiation to the human body within a specified period of time to below the safety standard value established as a safety standard. Safety standard when using optical fiber and ultraviolet laser light source: JIS C6803 Safety standard when using ultraviolet LED light source: https: / / www.jlma.or.jp / anzen / covid-19 / pdf / GLA_UV-C_Safety_Position_Statement_japanese.pdf

[0006] In order to ensure the safety of the irradiated ultraviolet light to the human body, the ultraviolet light irradiation system is equipped with sensors 19 such as an ultraviolet camera that monitors the irradiation status of the irradiation target area AR and a human presence sensor that detects the presence of a person, as shown in Fig. 3. The ultraviolet light irradiation system is equipped with a safety function that stops the output of the ultraviolet light source unit 11 and blocks ultraviolet light in the irradiation unit 13 when the sensor 19 determines that safety cannot be ensured.

[0007] 3 only monitors the ultraviolet light irradiated onto the irradiation target area AR using the sensor 19, and does not monitor the cumulative amount of ultraviolet light irradiated onto the human body. Because people, such as workers, move around, it is difficult to monitor the cumulative amount of ultraviolet light irradiated onto each person within a given period of time.

[0008] Therefore, in order to solve the above-mentioned problems, an object of the present invention is to provide an ultraviolet light irradiation system and a control method thereof that can monitor the cumulative irradiation amount of ultraviolet light for each person within a predetermined period of time.

[0009] In order to achieve the above object, the ultraviolet light irradiation system of the present invention is equipped with an ultraviolet light sensor carried by each worker that measures the cumulative amount of ultraviolet light irradiation within a specified period of time, and monitors this cumulative amount of irradiation.

[0010] Specifically, the ultraviolet light irradiation system according to the present invention is characterized by comprising: an ultraviolet light source unit that generates ultraviolet light; one or more irradiation units that irradiate each irradiation target area with the ultraviolet light; one or more portable ultraviolet light sensors carried by each worker that measure the cumulative irradiation amount of the ultraviolet light irradiated from the irradiation units to the irradiation target area; and a control unit that performs stop control to stop the irradiation of the ultraviolet light from the irradiation units when the cumulative irradiation amount for a predetermined period of time exceeds a specified value.

[0011] Furthermore, the control method according to the present invention is a control method for an ultraviolet light irradiation system in which ultraviolet light generated in an ultraviolet light source unit is irradiated onto each irradiation target area from one or more irradiation units, and is characterized by measuring the cumulative irradiation amount of the ultraviolet light irradiated onto the irradiation target area from the irradiation unit using one or more portable ultraviolet light sensors carried by each worker, and performing stop control to stop the irradiation of the ultraviolet light from the irradiation unit when the cumulative irradiation amount for a predetermined period of time exceeds a specified value.

[0012] To ensure safety against ultraviolet light irradiation, people are given an ultraviolet light sensor that monitors the cumulative amount of ultraviolet light irradiation. This ultraviolet light irradiation system manages the cumulative amount of irradiation for each person (sensor) within a specified period of time, and if the cumulative amount of irradiation exceeds the amount specified by safety standards, it cuts off the ultraviolet light output from the irradiation unit, thereby ensuring safety for people.

[0013] Therefore, the present invention can provide an ultraviolet light irradiation system and a control method thereof that can monitor the cumulative irradiation amount of ultraviolet light for each person within a predetermined period of time.

[0014] The ultraviolet light irradiation system according to the present invention is characterized in that it includes a plurality of irradiation units and further includes a branching unit that distributes the ultraviolet light from the ultraviolet light source unit to each of the irradiation units. This allows a single ultraviolet light source unit to supply ultraviolet light to a plurality of irradiation target areas, thereby improving work efficiency.

[0015] The control unit of the ultraviolet light irradiation system according to the present invention is characterized in that it performs the stop control for each of the irradiation units. Since it is possible to cut off the ultraviolet light output for each irradiation target area and continue to supply ultraviolet light to irradiation target areas other than the cut-off target, it is possible to shorten the time for sterilization or inactivation while ensuring safety.

[0016] The ultraviolet light sensor of the ultraviolet light irradiation system of the present invention can be characterized in that it transmits a shut-off signal when the accumulated irradiation amount over a predetermined period of time exceeds a specified value, and the control unit performs the stop control when it receives the shut-off signal.

[0017] On the other hand, in the ultraviolet light irradiation system according to the present invention, the ultraviolet light sensor has a function of determining its own current position and periodically transmits a notification signal including the accumulated irradiation amount for a predetermined time and the current position, and the control unit receives the notification signal and determines the accumulated irradiation amount and the current position for each ultraviolet light sensor, and can perform the stop control if even one ultraviolet light sensor whose accumulated irradiation amount for a predetermined time exceeds the specified value is present in the irradiation target area.

[0018] This UV light irradiation system adds a location information acquisition function to the UV light sensor, allowing for accurate tracking of each person's cumulative irradiation dose. Based on the person's location information and cumulative irradiation dose, this UV light irradiation system ensures safety for people by cutting off UV light output to the irradiation target area if the cumulative irradiation dose exceeds the safety standard. Furthermore, even if a person moves, it can also cut off UV light output to the irradiation target area after they move.

[0019] The ultraviolet light irradiation system according to the present invention is characterized in that the specified value is a value for each of the ultraviolet light sensors.

[0020] The UV light irradiation system in Figure 3 was designed with safety measures in mind, based on the idea of ​​providing sufficient virus protection by irradiating the target with UV light up to the safety standard value for the cumulative UV irradiation dose. This meant that it was not possible to flexibly design UV light irradiation according to each individual's condition within the safety standard, for example, for people who cannot be exposed to UV light and for people who have a margin for the cumulative irradiation dose and can be exposed to UV light up to the allowable amount. This UV light irradiation system can individually set the allowable cumulative UV irradiation dose for each person, allowing for a flexible design that irradiates UV light according to each individual's condition within the safety standard.

[0021] The control unit of the ultraviolet light irradiation system according to the present invention is characterized in that it cancels the stop control after a certain time has elapsed since the start of the stop control. When ultraviolet light irradiation is stopped, it does not remain stopped indefinitely, but rather restarts ultraviolet light irradiation and sterilization or inactivation when a certain time has elapsed (when the cumulative irradiation amount is reset) or when a person who has reached a specified value leaves the irradiation target area.

[0022] The above inventions can be combined as much as possible.

[0023] The present invention can provide an ultraviolet light irradiation system and a control method thereof that can monitor the cumulative irradiation amount of ultraviolet light for each person within a predetermined period of time.

[0024] FIG. 1 is a diagram illustrating an ultraviolet light irradiation system. FIG. 2 is a diagram illustrating an ultraviolet light irradiation system. FIG. 3 is a diagram illustrating an ultraviolet light irradiation system according to the present invention. FIG. 4 is a diagram illustrating an ultraviolet light irradiation system according to the present invention. FIG. 5 is a diagram illustrating an ultraviolet light irradiation system according to the present invention. FIG. 6 is a diagram illustrating an ultraviolet light irradiation system according to the present invention. FIG. 7 is a diagram illustrating an ultraviolet light irradiation system according to the present invention. FIG. 8 is a diagram illustrating an ultraviolet light irradiation system according to the present invention. FIG. 9 is a diagram illustrating an ultraviolet light irradiation system according to the present invention. FIG. 10 is a diagram illustrating an ultraviolet light irradiation system according to the present invention. FIG. 11 is a diagram illustrating an ultraviolet light irradiation system according to the present invention. FIG. 12 is a diagram illustrating a control method according to the present invention.

[0025] The following description of the preferred embodiments of the present invention will be given with reference to the accompanying drawings. The preferred embodiments described below are examples of the present invention, and the present invention is not limited to the preferred embodiments. In this specification and the drawings, components having the same reference numerals are intended to represent the same components.

[0026] (Embodiment 1) Figure 4 is a diagram illustrating an ultraviolet light irradiation system of this embodiment. This ultraviolet light irradiation system is characterized by comprising: an ultraviolet light source unit 11 that generates ultraviolet light; one or more irradiation units 13 that irradiate each irradiation target area AR with the ultraviolet light; one or more portable ultraviolet light sensors 20 carried by each worker that measure the cumulative irradiation amount of the ultraviolet light irradiated from the irradiation units 13 onto the irradiation target area AR; and a control unit 15 that performs stop control to stop the irradiation of the ultraviolet light from the irradiation units 13 when the cumulative irradiation amount over a predetermined time period exceeds a specified value. Note that the specified value is a value equal to or less than the cumulative irradiation amount for the human body over a predetermined time period specified in the safety standard mentioned above.

[0027] 5 to 10 show variations of the ultraviolet light irradiation system. The ultraviolet light irradiation system is characterized in that the ultraviolet light sensor transmits a shutdown signal CS when the integrated irradiation amount for a predetermined time period exceeds a specified value, and the control unit performs the stop control when it receives the shutdown signal CS.

[0028] 5 is a diagram showing a case where the control unit 15 is a blocking unit 15a provided in the irradiation unit 13. The blocking unit 15a provided in the irradiation unit 13 receives a blocking signal CS transmitted wirelessly from an ultraviolet light sensor 20 carried by a person, and blocks the ultraviolet light output from the irradiation unit 13. The wireless connection between the ultraviolet light sensor 20 and the blocking unit 15a may be any wireless method, such as Wi-Fi, Bluetooth, or a proprietary method.

[0029] The ultraviolet light sensor 20 transmits a cutoff signal CS when the cumulative irradiation amount measured over a predetermined period of time exceeds a specified value. Upon receiving the cutoff signal CS, the cutoff unit 15a activates the cutoff function and performs stop control to stop the irradiation of ultraviolet light from the irradiation unit 13. Because it is anticipated that people may move, the ultraviolet light sensor 20 continues to transmit the cutoff signal CS at any time interval while the cumulative irradiation amount exceeds the specified value.

[0030] After receiving the cutoff signal CS, the cutoff unit 15a releases the stop control after a certain time has elapsed (a certain time after the cutoff signal CS is no longer received), and resumes irradiating ultraviolet light from the irradiation unit 13.

[0031] 6 is a diagram illustrating a case in which the control unit 15 includes a receiving unit 15b in the irradiation unit 13 and a light source control unit 15c in the ultraviolet light source unit. The receiving unit 15b in the irradiation unit 13 receives a blocking signal CS wirelessly transmitted from an ultraviolet light sensor 20 carried by the person and notifies the light source control unit 15c of the information. The light source control unit 15c stops the ultraviolet light output from the irradiation unit 13 by causing the ultraviolet light source unit 11 to stop outputting ultraviolet light. The wireless connection between the ultraviolet light sensor 20 and the receiving unit 15b may be any wireless method, such as Wi-Fi, Bluetooth, or a proprietary method. Furthermore, the communication method between the light source control unit 15c and the receiving unit 15b may be a wireless method, optical communication using optical fiber 16, or a separately provided wired method.

[0032] The ultraviolet light sensor 20 transmits a shutoff signal CS when the cumulative irradiation amount measured over a predetermined period of time exceeds a specified value. The receiver 15b receives the shutoff signal CS and notifies the light source controller 15c of the shutoff signal CS. The light source controller 15c controls the ultraviolet light output of the ultraviolet light source unit 11 to stop the irradiation of ultraviolet light from the irradiation unit 13. Because it is anticipated that people may move, the ultraviolet light sensor 20 continues to transmit the shutoff signal CS at any time interval while the cumulative irradiation amount exceeds the specified value.

[0033] After receiving the shut-off signal CS, the light source control unit 15c releases the stop control after a certain time has elapsed (a certain time after the shut-off signal CS is no longer received), resumes the output of ultraviolet light from the ultraviolet light source unit 11, and resumes the irradiation of ultraviolet light from the irradiation unit 13.

[0034] Fig. 7 is a diagram illustrating an ultraviolet light irradiation system having a plurality of (N) irradiation units 13 and further including a branching unit 12 that distributes the ultraviolet light from the ultraviolet light source unit 11 to each of the irradiation units 13. Fig. 8 shows a configuration in which each irradiation unit 13 includes a blocking unit 15a, Fig. 9 shows a configuration in which each irradiation unit 13 includes a receiving unit 15b and the branching unit 12 includes a branching control unit 15d, and Fig. 10 shows a configuration in which each irradiation unit 13 includes a receiving unit 15b and the ultraviolet light source unit 11 includes a light source control unit 15c. Even if there are a plurality of irradiation units 13, the stop control described in Figs. 4 to 6 can be performed.

[0035] 9 operates as follows: A blocking signal CS transmitted wirelessly from an ultraviolet light sensor 20 carried by a person is received by a receiver 15b provided in each irradiation unit 13, and the information is notified to a branching control unit 15d. The branching control unit 15d controls the branching unit 12 to stop the supply of ultraviolet light to the irradiation unit 13 in the irradiation target area AR where the ultraviolet light sensor 20 that transmitted the blocking signal CS is located. This blocks the ultraviolet light output from the irradiation unit 13.

[0036] The wireless connection between the ultraviolet light sensor 20 and the receiving unit 15b may be any wireless method such as Wi-Fi, Bluetooth, a proprietary method, etc. The communication method between the branching control unit 15d and the receiving unit 15b may be a wireless method, optical communication using the optical fiber 16, or a separately prepared wired method.

[0037] The ultraviolet light sensor 20 transmits a shutoff signal CS when the cumulative irradiation amount measured over a predetermined period of time exceeds a specified value. The receiver 15b, upon receiving the shutoff signal CS, notifies the branching controller 15d of the shutoff signal CS. The branching controller 15d performs stop control to stop the irradiation of ultraviolet light from the irradiation unit 13 by controlling the supply destination of the ultraviolet light. Because it is anticipated that people may move, the ultraviolet light sensor 20 continues to transmit the shutoff signal CS at any time interval while the cumulative irradiation amount exceeds the specified value.

[0038] After receiving the cutoff signal CS, the branch control unit 15d releases the stop control after a certain time has elapsed (a certain time after the cutoff signal CS is no longer received), resumes the ultraviolet light output to the path for which the ultraviolet light supply has been stopped, and resumes the irradiation of ultraviolet light from the irradiation unit 13.

[0039] In the ultraviolet light irradiation system having the configuration shown in FIG. 8 or 9, the control unit 15 can perform stop control for each irradiation unit 13.

[0040] 11 is a diagram illustrating an ultraviolet light irradiation system according to the second embodiment. This ultraviolet light irradiation system differs from the ultraviolet light irradiation system according to the first embodiment in that it does not use a cutoff signal CS but instead manages the position information and the integrated irradiation amount of each ultraviolet light sensor.

[0041] Specifically, this ultraviolet light irradiation system differs from the ultraviolet light irradiation system of Figure 7 in that the ultraviolet light sensor 20 has the function of determining its own current position and periodically transmits a notification signal IS including the accumulated irradiation amount for a predetermined time period and the current position, the control unit 15 receives the notification signal IS and determines the accumulated irradiation amount and the current position for each ultraviolet light sensor 20, and performs the stop control if even one ultraviolet light sensor 20 whose accumulated irradiation amount for a predetermined time period exceeds the specified value is present in the irradiation target area AR.

[0042] The ultraviolet light sensor 20 acquires its own position information in addition to the cumulative dose of ultraviolet light irradiated. A global positioning system such as GPS can be used as a means for acquiring the position information. Another means for acquiring the position information is to add information for each irradiation target area AR by modulating the ultraviolet light irradiated by the irradiation unit, and then acquire the position information (which irradiation target area AR the sensor is located in) by determining the ultraviolet light modulation information. The ultraviolet light sensor 20 periodically transmits the cumulative dose and the position information as a notification signal IS.

[0043] The control unit 15 receives the notification signal IS and manages the cumulative irradiation amount (for each person) for each ultraviolet light sensor 20. When there is a person (hereinafter referred to as "the person") whose cumulative irradiation amount is equal to or greater than a specified value, the control unit 15 performs stop control to stop irradiation of ultraviolet light to the irradiation target area AR where the person is located based on the position information.

[0044] A case where the control unit 15 is the blocking unit 15a will be described. For example, assume that a worker holding the ultraviolet light sensor 20a is located in the irradiation target area AR1, a worker holding the ultraviolet light sensor 20b and a worker holding the ultraviolet light sensor 20c are located in the irradiation target area AR2, and a worker holding the ultraviolet light sensor 20d is located in the irradiation target area ARN.

[0045] Each ultraviolet light sensor (20a to 20d) periodically transmits the integrated dose and its own position information as a notification signal IS to the blocking unit 15a in the irradiation target area AR where it is located. The blocking units 15a cooperate with each other and centrally manage the integrated dose and position information of each ultraviolet light sensor (20a to 20d) based on the received notification signal IS.

[0046] Based on the centrally managed information, the blocking unit 15a of the irradiation unit 13 in the irradiation target area AR where even one person is present blocks the ultraviolet light emitted from the irradiation unit 13. For example, if the person is a worker carrying ultraviolet light sensor 20c, the blocking unit 15a of the irradiation unit 13-2 identifies the irradiation target area AR2 from the position information of ultraviolet light sensor 20c and stops the irradiation of ultraviolet light to the irradiation target area AR2 even if another person (having ultraviolet light sensor 20b) whose cumulative irradiation dose is below the specified value is present in the irradiation target area AR2. On the other hand, the blocking unit 15a of the irradiation unit (13-1 or 13-N) continues the irradiation of ultraviolet light to other irradiation target areas (AR1 or ARN) where workers carrying ultraviolet light sensors (20a, 20d) whose cumulative irradiation dose is below the specified value are present.

[0047] Next, a case where the control unit 15 is the branch control unit 15d will be described. Similarly, it is assumed that a worker holding the ultraviolet light sensor 20a is located in the irradiation target area AR1, a worker holding the ultraviolet light sensor 20b and a worker holding the ultraviolet light sensor 20c are located in the irradiation target area AR2, and a worker holding the ultraviolet light sensor 20d is located in the irradiation target area ARN.

[0048] Each ultraviolet light sensor (20a to 20d) periodically transmits the integrated irradiation amount and its own position information as a notification signal IS to the branching control unit 15d via the receiving unit (15b-1 to 15b-N) provided in each irradiation unit (13-1 to 13-N). The branching control unit 15d centrally manages the integrated irradiation amount and position information of each ultraviolet light sensor (20a to 20d) based on the received notification signal IS.

[0049] Based on the centrally managed information, the branch control unit 15d stops the supply of ultraviolet light to the irradiation unit 13 in the irradiation target area AR where even one person in question is present, thereby blocking the ultraviolet light emitted from the irradiation unit 13. For example, if the person in question is a worker carrying ultraviolet light sensor 20c, the branch control unit 15d identifies the irradiation target area AR2 from the position information of ultraviolet light sensor 20c, and stops the supply of ultraviolet light to the irradiation unit 13-2 and stops the irradiation of ultraviolet light to the irradiation target area AR2 even if another person (having ultraviolet light sensor 20b) whose cumulative irradiation amount is below a specified value is present in the irradiation target area AR2. On the other hand, the branch control unit 15d continues the irradiation of ultraviolet light to other irradiation target areas (AR1 and ARN) where workers carrying ultraviolet light sensors (20a, 20d) whose cumulative irradiation amount is below the specified value are present.

[0050] In addition, when the control unit 15 is the light source control unit 15c, it is not possible to irradiate / block ultraviolet light for each irradiation target area AR. As in the case of the branch control unit 15d, each ultraviolet light sensor (20a to 20d) periodically transmits the integrated irradiation amount and its own position information as a notification signal IS to the light source control unit 15c via the receiving unit (15b-1 to 15b-N) provided in each irradiation unit (13-1 to 13-N), and the light source control unit 15c centrally manages the integrated irradiation amount and position information of each ultraviolet light sensor (20a to 20d) based on the received notification signal IS.

[0051] However, even if the light source control unit 15c identifies the irradiation target area AR2 from the position information of the ultraviolet light sensor 20c carried by the person, the output of the ultraviolet light source unit 11 is stopped, and therefore the ultraviolet light from all irradiation units (13-1 to 13-N) is blocked.

[0052] In either case, the control unit 15 has knowledge of the position information of the ultraviolet light sensor 20, and therefore can know when the worker has left the irradiation target area AR or moved between irradiation target areas AR. Therefore, when the worker leaves the irradiation target area AR, the ultraviolet light irradiation system can resume irradiating the irradiation target area AR with ultraviolet light. Furthermore, when the worker moves between irradiation target areas AR, the ultraviolet light irradiation system can block ultraviolet light in the irradiation target area AR to which the worker has moved.

[0053] In this embodiment, the wireless connection method between the ultraviolet light sensor 20 and the blocking unit 15a or receiving unit 15b, and the communication method between the receiving unit 15b and the light source control unit 15c or branching control unit 15d are the same as those described in embodiment 1.

[0054] (Embodiment 3) Fig. 12(A) is a diagram illustrating an ultraviolet light irradiation system of this embodiment. This ultraviolet light irradiation system differs from the ultraviolet light irradiation system of embodiment 2 in that the specified value is a value for each ultraviolet light sensor 20. Fig. 12(B) is a diagram illustrating the specified value for each ultraviolet light sensor 20 (operator) set in the control unit 15. The α value is the maximum cumulative irradiation amount defined by safety standards.

[0055] Except for the fact that the specified value differs for each worker, the operation of the ultraviolet light irradiation system of this embodiment is the same as that of the ultraviolet light irradiation system described in Embodiment 2. The ultraviolet light irradiation system of this embodiment can flexibly accommodate requests for ultraviolet light irradiation according to the condition of each worker within safety standards, such as for a person who cannot be irradiated with ultraviolet light and a person who has a margin for the cumulative irradiation amount and can be irradiated with ultraviolet light up to the allowable amount.

[0056] 13 is a diagram illustrating a control method for controlling the ultraviolet light irradiation system described above. This control method is a control method for an ultraviolet light irradiation system in which ultraviolet light generated by an ultraviolet light source unit 11 is irradiated onto each irradiation target area AR from one or more irradiation units 13, and is characterized by measuring an integrated irradiation amount of the ultraviolet light irradiated onto the irradiation target area AR from the irradiation units 13 using one or more portable ultraviolet light sensors 20 carried by each worker (step S01), and performing stop control to stop irradiation of the ultraviolet light from the irradiation units 13 when the integrated irradiation amount over a predetermined time period exceeds a specified value (step S02).

[0057] Furthermore, the present control method may also include canceling the stop control after a certain time has elapsed since the start of the stop control (step S03).

[0058] (Effects) The present invention can realize an ultraviolet light irradiation system using a branched optical fiber that can be tailored to the needs of each individual, even in areas where multiple people are present. This makes it possible to build a system that efficiently sterilizes or inactivates viruses while ensuring safety for people.

[0059] 11: Ultraviolet light source unit 12: Branching unit 13, 13-1, 13-2, ..., 13-N: Irradiation unit 15: Control unit 15a: Blocking unit 15b: Receiving unit 15c: Light source control unit 15d: Branching control unit 16: Optical fiber 20, 20a, 20b, 20c, 20d: Ultraviolet light sensor

Claims

1. An ultraviolet light irradiation system comprising: an ultraviolet light source unit that generates ultraviolet light; one or more irradiation units that irradiate each irradiation target area with the ultraviolet light; one or more portable ultraviolet light sensors carried by each worker that measure an accumulated irradiation amount of the ultraviolet light irradiated from the irradiation unit to the irradiation target area; and a control unit that performs stop control to stop the irradiation of the ultraviolet light from the irradiation unit when the accumulated irradiation amount for a predetermined period of time exceeds a specified value.

2. The ultraviolet light irradiation system according to claim 1, further comprising a branching section for distributing the ultraviolet light from the ultraviolet light source section to each of the irradiation sections.

3. The ultraviolet light irradiation system according to claim 2, characterized in that the control unit performs the stop control for each of the irradiation units.

4. An ultraviolet light irradiation system according to any one of claims 1 to 3, characterized in that the ultraviolet light sensor transmits a cutoff signal when the accumulated irradiation amount for a predetermined period of time exceeds a specified value, and the control unit performs the stop control when the cutoff signal is received.

5. The ultraviolet light irradiation system of any one of claims 1 to 3, characterized in that the ultraviolet light sensor has a function of determining its own current location and periodically transmits a notification signal including the accumulated irradiation amount for a specified time and the current location, and the control unit receives the notification signal to determine the accumulated irradiation amount and the current location for each ultraviolet light sensor, and performs the stop control if even one ultraviolet light sensor whose accumulated irradiation amount for a specified time exceeds the specified value is present in the irradiation target area.

6. The ultraviolet light irradiation system according to claim 5, wherein the specified value is a value for each of the ultraviolet light sensors.

7. An ultraviolet light irradiation system as described in any one of claims 1 to 3, characterized in that the control unit cancels the stop control after a certain period of time has elapsed since the start of the stop control.

8. A control method for an ultraviolet light irradiation system that irradiates ultraviolet light generated in an ultraviolet light source unit from one or more irradiation units to each irradiation target area, the control method comprising: measuring an accumulated irradiation amount of the ultraviolet light irradiated from the irradiation unit to the irradiation target area with one or more portable ultraviolet light sensors carried by each worker; and performing stop control to stop the irradiation of the ultraviolet light from the irradiation unit when the accumulated irradiation amount for a specified period of time exceeds a specified value.

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