Patent Application
20240216559
The present disclosure relates to an ultraviolet light irradiation system that performs sterilization and virus inactivation using ultraviolet light.
For the purpose of preventing infectious diseases and the like, there is an increasing demand for a system that performs sterilization and virus inactivation using ultraviolet light. There are roughly three categories of products of the system. Note that, in the present specification, the term “sterilization or the like” means sterilization and virus inactivation.
The product of Non Patent Literature 1 is an autonomous mobile robot that emits ultraviolet light. The robot can automatically perform sterilization or the like in a wide range without human intervention by emitting ultraviolet light while moving in a room in a building such as a hospital room.
The product of Non Patent Literature 2 is a device that is installed on a ceiling or at a predetermined place in a room and performs sterilization or the like of air in the room while circulating the air. The device does not directly emit ultraviolet light and does not affect the human body, and thus highly safe sterilization can be performed.
The product of Non Patent Literature 3 is a portable device in which an ultraviolet light source is mounted. A user can bring the device to a desired area and emit ultraviolet light. Thus, the device can be used in various places.
However, the devices described in this non patent literature have the following problems.
Since the product of Non Patent Literature 1 emits high-output ultraviolet light, the device becomes large-scale and expensive. Thus, the product of Non Patent Literature 1 has a problem that it is difficult to achieve an economical system.
In the product of Non Patent Literature 1, since the ultraviolet light irradiation site is limited to a place where the robot can move and enter, it is difficult to irradiate a small place, a deep place, or the like with ultraviolet light.
In the product of Non Patent Literature 2, since the circulated indoor air is sterilized, a place to be sterilized or the like cannot be directly irradiated with ultraviolet light.
In the product of Non Patent Literature 3, for example, a thin pipe line or an area into which a person cannot enter cannot be irradiated with ultraviolet light.
As described above, the products of the non patent literatures have a problem with regard to the versatility of being able to irradiate any place with ultraviolet light.
The product of Non Patent Literature 3 is portable and can irradiate various places with ultraviolet light. However, in order to obtain a sufficient effect such as sterilization at the target site, the user is required to have skill and knowledge, and there is a problem in operability.
To solve these problems, an ultraviolet light irradiation system using an optical fiber as illustrated in
However, implementation of the P-MP configuration as an ultraviolet light irradiation system has the following problems.
In the case of the P-MP configuration using the beam splitter as illustrated in
A P-MP configuration that solves the above problem of excessive loss is a P-MP configuration using an optical switch. If the optical switch is configured to communicate with any of the plurality of output ports by switching the path of the ultraviolet rays input from one port by a mechanical mechanism (move optical fiber, mirror, prism, and the like) or a mechanism by MEMS, the multistage branched configuration is not formed. Thus, the passage loss of the optical switch is hardly affected by the number of branches, and the problem of excessive loss can be solved.
On the other hand, in the configuration of the optical switch, since the ultraviolet rays are intermittently transmitted to each output port by the path switching operation, it is difficult to perform simultaneous and constant sterilization of a plurality of sites, or the like. Thus, in the ultraviolet light irradiation system having the P-MP configuration using the optical switch, it is necessary to perform switching control in consideration of an effect such as constant sterilization on a plurality of target sites.
However, the switching control method is not clarified.
In order to solve these problems, an object of the present invention is to provide an ultraviolet light irradiation system and an ultraviolet light irradiation method having a P-MP configuration capable of obtaining an effect such as predetermined sterilization.
In order to achieve the above object, in an ultraviolet light irradiation system according to the present invention, an optical switch is disposed between an ultraviolet light source unit and an irradiation unit, and a path of ultraviolet light is switched at a predetermined timing.
Specifically, an ultraviolet light irradiation system according to the present invention includes:
Further, an ultraviolet light irradiation method according to the present invention is an ultraviolet light irradiation method for irradiating a desired site with ultraviolet light generated by an ultraviolet light source unit from N (N is a natural number) irradiation units, the method including
The present ultraviolet light irradiation system has a system configuration in which the ultraviolet light source and the irradiation units are connected via the optical switch, and a path of ultraviolet light is switched at a predetermined timing by the optical switch. The timing is obtained from output power of the ultraviolet light source, the number of output ports of the optical switch, an optical fiber transmission loss to each target site, an ultraviolet light illuminance obtained at each target site, and necessary ultraviolet light energy. With this configuration, even in a configuration in which ultraviolet light is intermittently transmitted to each target site by the optical switch, it is possible to ensure that the time during which sterilization or the like is not performed at a plurality of target sites is suppressed to a certain value or less, and it is possible to reduce an infection risk.
Therefore, the present invention can provide an ultraviolet light irradiation system and an ultraviolet light irradiation method having a P-MP configuration capable of obtaining a predetermined effect such as sterilization.
The ultraviolet light irradiation system according to the present invention further includes
The present ultraviolet light irradiation system has a sensing function of detecting whether or not a person is present in the vicinity of each target site, and performs control to stop the ultraviolet light irradiation or shift the irradiation timing for the site where the person is detected.
For example, the switching control unit may separately give the opportunity to the one path after the avoiding object becomes absent, give the opportunity for the one path to another of the paths, or supply the ultraviolet light only at the opportunity after the avoiding object becomes absent.
Note that the inventions described above can be combined in any possible manner.
The present invention can provide an ultraviolet light irradiation system and an ultraviolet light irradiation method having a P-MP configuration capable of obtaining a predetermined effect such as sterilization.
Embodiments of the present invention will be described with reference to the accompanying drawings. The embodiment described below is an example of the present invention, and the present invention is not limited to the following embodiment. Note that like components are denoted by like reference numerals in this specification and the drawings.
The ultraviolet light irradiation system 301 includes:
The ultraviolet light source unit 11 outputs light (ultraviolet light) in an ultraviolet region effective for sterilization and the like. The power of the ultraviolet light output from the ultraviolet light source unit 11 is defined as P [W]. The ultraviolet light source unit 11 and the optical switch 12 are connected by an optical fiber or a spatial path 16.
The switching control unit 15 controls the switching operation of the optical switch 12.
The optical switch 12 outputs the ultraviolet light from the ultraviolet light source unit 11 to any one path 14 of the plurality of output ports in accordance with an instruction from the switching control unit 15. Here, the time required for the optical switch 12 to switch the path is defined as Tsw [s]. The ultraviolet light output from the output ports 1 to N is emitted to the irradiation target regions 1 to N via the path 14 and the irradiation unit 13, respectively.
The path 14 propagates the ultraviolet light intermittently distributed by the optical switch 12 to each irradiation unit 13. The path 14 is an optical fiber. Since this is an optical fiber, the optical fiber can be laid in a small place where a robot or a device of the related art cannot enter.
This optical fiber has one solid core 52 having a refractive index higher than that of a clad 60, in the clad 60. As used herein, the term “solid” means “not hollow”. Furthermore, the solid core can also be made by forming an annular low refractive index region in the clad.
The optical fiber has the solid core 52 and a plurality of holes 53 arranged on the outer periphery thereof, in the clad 60. The medium of the hole 53 is air, and the refractive index of air is sufficiently smaller than that of quartz-based glass. Thus, the hole assisted optical fiber has a function of returning light leaked from the core 52 by bending or the like to the core 52 again, and has a small bending loss.
This optical fiber has a hole group 53a of the plurality of holes 53 in the clad 60, and has a refractive index effectively lower than that of a host material (glass or the like). This structure is called a photonic crystal fiber. This structure can have a structure in which a high refractive index core having a changed refractive index does not exist, and light can be confined using a region 52a surrounded by the holes 53 as an effective core region. Compared with an optical fiber having a solid core, the photonic crystal fiber can reduce the influence of absorption and scattering loss due to additives in the core, and can realize optical characteristics that cannot be realized by a solid optical fiber, such as reduction of bending loss and control of a nonlinear effect.
In the optical fiber, a core region is formed of air. When the clad region has a photonic bandgap structure formed by the plurality of holes or an anti-resonance structure formed of a thin glass wire, light can be confined in the core region. The optical fiber has a small nonlinear effect, and can supply a high-power or high-energy laser.
The optical fiber has a plurality of solid cores 52 that have a high refractive index arranged close to each other in the clad 60. The optical fiber guides light between the solid cores 52 by optical wave coupling. Since the coupling core type optical fiber can disperse and transmit light by the number of cores, the power can be increased accordingly and efficient sterilization can be performed, and then the coupling core type optical fiber has an advantage that fiber degradation due to ultraviolet rays can be alleviated and the life can be extended.
The irradiation unit 13 irradiates a predetermined target site (irradiation target region ste) to be sterilized or the like with the ultraviolet light transmitted through the path 14. The irradiation unit 13 includes an optical system such as a lens designed for a wavelength of ultraviolet light. Here, the loss from the ultraviolet light source unit 11 to the irradiation unit 13 (including the passage loss of the optical switch 12) is defined as Lfiber [a.u.], and the loss from the irradiation unit 13 to the irradiation target region ste is defined as Lair [a.u.]. Further, the area of the spot of the ultraviolet light with which the irradiation target region ste is irradiated is defined as S [m2].
The switching control unit 15 controls the optical switch 12 to repeat an operation of giving an opportunity to supply the ultraviolet light for the time T to each path 14 (the output ports 1 to N of the optical switch). The time T is defined as a time obtained by Equation (1).
Here, E [W·s/m2] is the amount of ultraviolet light necessary for sterilization and the like.
By operating the optical switch 12 in this way and supplying the ultraviolet light at the opportunity, the ultraviolet ray amount E [W·s/m2] necessary for sterilization and the like can be irradiated to all the irradiation target regions ste in the shortest cycle. That is, the ultraviolet light irradiation system 301 can ensure an effect such as sterilization for each irradiation target region ste at every time Tinact [s] of Expression (2).
Note that, even if the switching control unit 15 controls the optical switch 12 so that the time of opportunity to supply ultraviolet light to each output port is T/M [s] (M is a natural number of 2 or more), a similar effect can be obtained.
The power of the ultraviolet light output from the ultraviolet light source unit 11 is defined as P [W]. A time required for path switching by the optical switch 12 is defined as Tsw [s]. The loss from the ultraviolet light source unit 11 to the irradiation unit 13 (including the passage loss of the optical switch 12) is Lfiber-1 [a.u.] for each path 14, and Lfiber-2 [a.u.], . . . , Lfiber-N [a.u.] is defined. The loss from the irradiation unit 13 to each irradiation target region ste is defined as Lair-1 [a.u.], Lair-2 [a.u.], . . . , and Lair-N [a.u.]. Further, the area of the spot of the ultraviolet light irradiated to each irradiation target region ste is defined as S1 [m2], S2 [m2], . . . , SN [m2].
The switching control unit 15 controls the optical switch 12 to repeat an operation of giving an opportunity to supply the ultraviolet light for the time Ti to each of the output ports i (i=1, 2, . . . , N). Ti is defined as a time obtained by Expression (3).
Here, E [W·s/m2] is the amount of ultraviolet light necessary for sterilization and the like.
By operating the optical switch 12 in this way and supplying the ultraviolet light at the opportunity, the ultraviolet ray amount E [W·s/m2] necessary for sterilization and the like can be irradiated to all the irradiation target regions ste in the shortest cycle. That is, the ultraviolet light irradiation system 302 can ensure an effect such as sterilization for each irradiation target region ste at every time Tinact [s] of Expression (4).
Note that, even if the switching control unit 15 controls the optical switch 12 so that the time of opportunity to supply ultraviolet light to each output port is T/M [s] (M is a natural number of 2 or more), a similar effect can be obtained.
That is, the ultraviolet light irradiation system 303 further includes the sensor 21 that detects the presence of the avoiding object at which the ultraviolet light is to be avoided at the desired site (irradiation target region ste) with respect to the ultraviolet light irradiation system 301 of
In the present embodiment, only portions different from the ultraviolet light irradiation system (301 or 302) will be described.
Each sensor 21-i acquires various types of information Di (i=1, 2, . . . , N) of each irradiation target region ste and detects the presence or absence of the avoiding object. As a combination of the “sensor” and the “various types of information”, for example, the following is conceivable.
When the sensor 21 is a camera, the various types of information Di are video information.
When the sensor 21 is an infrared sensor, the various types of information Di are temperature information.
When the sensor 21 is a microphone, the various types of information Di are voice information.
Each sensor 21-i transmits information Di to the switching control unit 15 via the path 24. A wired communication method (for example, a wired LAN or the like) or a wireless communication method (for example, a wireless LAN or the like) can be applied to the path 24.
The switching control unit 15 performs switching control of the optical switch 12 on the basis of the information Di.
The switching control unit 15 adds the following control to the switching control described with reference to
Specifically described with reference to the examples of
Although the ultraviolet light is harmful to the human body depending on the wavelength, the ultraviolet light irradiation system 303 can perform the control described in the control modes 1 and 2 while avoiding the ultraviolet light irradiation to a person by this control.
The switching control unit 15 adds the following control to the switching control described with reference to
Specific description will be given with reference to the examples of
The ultraviolet light irradiation system 303 can also perform the control described in the control modes 1 and 2 while avoiding the ultraviolet irradiation of the person by this control, similarly to the control example of
In addition, in the control example of
The switching control unit 15 adds the following control to the switching control described with reference to
This will be specifically described with reference to the examples of
The ultraviolet light irradiation system 303 can also perform the control described in the control modes 1 and 2 while avoiding the ultraviolet irradiation of the person by this control, similarly to the control example of
In this control, in addition to the operations of the control modes 1 and 2, it is possible to avoid ultraviolet irradiation to a person and to avoid unnecessary ultraviolet irradiation to a site where sterilization or the like is unnecessary.
The present invention has a characteristic in a system configuration in which an ultraviolet light source and an irradiation unit installed in the vicinity of a target site for sterilization or the like are connected via an optical switch, and a path in the optical switch is switched at a predetermined timing. According to this characteristic, it is possible to prevent a decrease in ultraviolet light power due to the multistage configuration for the irradiation target region, and it is possible to reduce the infection risk while securing a certain effect such as sterilization.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/021429 | 6/4/2021 | WO |
