Patent Application
20240181099
The present disclosure relates to an ultraviolet (UV) light irradiation system and decontamination each of which perform sterilization and virus inactivation using UV rays.
For the purpose of preventing infectious diseases, there is an increasing demand for a system that performs sterilization and virus inactivation using UV rays that using UV rays. In the present embodiment, the term “decontamination” includes sterilization and virus inactivation.
There are roughly three categories of products for decontamination systems.
Mobile sterilizing robots are autonomous mobile robots emitting UV rays. The mobile sterilizing robot can automatically achieve decontamination in a wide range without human intervention by emitting UV rights while moving in a room in a building, such as a hospital room. Refer to, for example, the Kantum Ushikata website (https://www.kantum.co.jp/product/sakkin_robot/sakkinn_robot/UVD_robot).
Stationary air purifiers are devices installed on a ceiling or at a predetermined place in a room to circulate and decontaminate air in the room. The stationery air purifier does not emit UV rays to the outside and affect the human body, and thus highly reliable contamination is expected. Refer to, for example, the IWASAKI Electric website (https://www.iwasaki.co.jp/optics/sterilization/air/air03.html).
Portable sterilization devices are portable devices equipped with UV light sources such as florescent lamps, mercury lamps or LEDs. A user takes the portable sterilization device to an area where decontamination is desired, and irradiates the area with UV rays. The portable sterilization device can be used in various places. Refer to, for example, the Funakoshi website (https://www.funakoshi.co.jp/contents/68182).
However, the prior art has difficulties as follows:
As a solution for the challenges (1) to (3) stated above, optical fiber-based systems have been proposed. By transmitting UV rays from a light source using a thin and bendable optical fiber, it is possible to have flexibility to irradiate a desired place with UV rays output from a fiber tip with enhanced accuracy. Further, a P-MP system configuration used in FTTH (fiber-to-the-home) can lead to higher economic performance by sharing a single light source.
However, the optical fiber-based system has a problem of deterioration in transmission characteristics of the fiber due to transmission of UV rays (see, for example, Non Patent Literature 1). By transmitting high energy light in the ultraviolet region, defects occur in a core glass, and the transmission loss characteristics deteriorate over time. Accordingly, the UV ray power emitted from the optical fiber output end is reduced, leading to insufficient decontamination. Although an operation method of replacing a deteriorated optical fiber can also be adopted, there is a possibility that frequent replacement will occur depending on usage conditions, potentially leading to complicated operation, and thus a demand for efficient solutions remains unchanged.
In short, a decontamination system using the conventional optical fiber has challenges that, in a case where UV rays have a high power, the UV ray power would be reduced due to deterioration of transmission loss characteristic over time.
The present invention is intended to solve such challenges, and an object thereof is to provide an ultraviolet light irradiation system and an ultraviolet light irradiation method, each of which is capable of reducing deterioration over time of transmission loss characteristics of an optical fiber due to UV rays and preventing a decrease in UV ray irradiation power.
For achieving the object, the ultraviolet light irradiation system according to the present invention causes transmission through some sections, through which UV rays propagate in space-division multiplexing (SDM).
In particular, an ultraviolet light irradiation system according to the present invention includes:
Furthermore, an ultraviolet light irradiation method according to the present invention is an ultraviolet light irradiation method for irradiating a desired location with ultraviolet rays generated from an ultraviolet light source unit by N irradiation units, N being a natural number,
The ultraviolet light irradiation system can irradiate a contaminated site with UV rays having sufficient decontamination power by multiplexing UV rays output from the plurality of fibers while mitigating damage to a transmission path by transmitting UV rays having a high energy density from the ultraviolet light source dispersed by the plurality of fibers. Consequently, with the present invention, it is possible to provide an ultraviolet light irradiation system and an ultraviolet light irradiation method, each of which is capable of reducing deterioration over time of transmission loss characteristics of an optical fiber due to ultraviolet rays and preventing a decrease in ultraviolet ray irradiation power.
In the ultraviolet light irradiation system according to the present invention, the ultraviolet light source unit may be configured to include a plurality of light sources, and the ultraviolet ray output from each of the light sources may be subjected to space-division multiplexing in the propagation section.
In the ultraviolet light irradiation system according to the present invention, the ultraviolet light source unit may be configured to include a light branching unit configured to branch the ultraviolet ray, and each branched portion of the ultraviolet ray may be subjected to space-division multiplexing in the propagation section.
The ultraviolet light irradiation system according to the present invention may further include a photosynthesis unit configured to multiplex all the ultraviolet light, which has been subjected to space-division multiplexing and propagated through the propagation section, provided between the propagation section and the supply section in a case where N is 1.
The ultraviolet light irradiation system according to the present invention may further include a photosynthesis distribution unit configured to divide the ultraviolet rays subjected to space-division multiplexing and propagated through the propagation section into N groups, and to multiplex the ultraviolet rays for each group to input the rays to the N single-core optical fibers, provided between the propagation section and the supply section in a case where N is >2.
In the ultraviolet light irradiation system according to the present invention, the photosynthesis distribution unit may be connected in multiple stages.
In the ultraviolet light irradiation system according to the present invention, the propagation section may be an optical cable that bundles any of a solid core optical fiber, a hole assisted optical fiber, a hole structure optical fiber, a hollow core optical fiber, a coupling core type optical fiber, a solid core type multi-core optical fiber, a hole assisted type multi-core optical fiber, a hole structure type multi-core optical fiber, a hollow core type multi-core optical fiber, and a coupling core type multi-core optical fiber, or alternatively, any one of a solid core type multi-core optical fiber, a hole assisted type multi-core optical fiber, a hole structure type multi-core optical fiber, a hollow core type multi-core optical fiber, and a coupling core type multi-core optical fiber.
The respective inventions above may be combined to any possible extent.
With the present invention, it is possible to provide an ultraviolet light irradiation system and an ultraviolet light irradiation method, each of which is capable of reducing deterioration over time of transmission loss characteristics of an optical fiber due to ultraviolet rays and preventing a decrease in ultraviolet ray irradiation power.
An embodiment 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. Components having the same reference numerals in the present specification and the drawings indicate the same components.
The ultraviolet light source unit 11 and the irradiation unit 13 installed near a target place Ar to be decontaminated are connected via the photosynthesis unit 15 or the photosynthesis distribution unit 16. In the propagation section 50 in which the optical power of the UV ray is large from the ultraviolet light source unit 11 to the photosynthesis unit 15/photosynthesis distribution unit 16, a plurality of (single core or multi-core) optical fibers are bundled and connected by an optical cable or a multi-core optical fiber. The optical power of the UV ray decreases due to the transmission loss in the propagation section 50. Therefore, the supply section 51 from the photosynthesis unit 15/photosynthesis distribution unit 16 to the irradiation unit 13 can be connected by a single-core optical fiber.
The photosynthesis unit 15 synthesizes output light beams from the plurality of optical fibers or cores and inputs the synthesized light beams to the single-core optical fiber (see a first embodiment described below).
The photosynthesis distribution unit 16 synthesizes output light beams from the plurality of optical fibers or cores, distributes the synthesized light beams, and inputs the light beams to the plurality of single-core optical fibers (see a second embodiment described below).
With this configuration, in the propagation section 50 in which the optical power of the UV ray is large, the entire power is distributed and transmitted to the plurality of optical fibers or cores, so that the problem of characteristic deterioration of each optical fiber or core can be alleviated and efficient operation can be expected.
Furthermore, in the supply section 51, by using a single-core optical fiber having a simple configuration and being thinner, it is possible to implement a system having excellent economic efficiency and capable of being laid in a narrow space.
The ultraviolet light irradiation system 301 further includes the photosynthesis unit 15 configured to multiplex all the ultraviolet light, which has been subjected to space-division multiplexing and propagated through the propagation section 50, provided between the propagation section 50 and the supply section 51 in a case where N is 1.
That is, the optical cable of the single-core optical fiber or the multi-core optical fiber, or the multi-core optical fiber, illustrated in
This optical fiber has one solid core 52 having a refractive index higher than that of a clad 60 in the clad 60. “Solid” means “not hollow”. Furthermore, the solid core can also be realized 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 the air is sufficiently smaller than that of quartz-based glass. Therefore, 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 non-linear effect.
In this optical fiber, a core region is formed of air. Light can be confined in the core region by adopting a photonic band gap structure configured with a plurality of holes or an anti-resonance structure configured with a thin glass wire in the clad region. This optical fiber has a small nonlinear effect, and can supply a high-power or high-energy laser.
In this optical fiber, a plurality of solid cores 52 having a high refractive index are arranged close to each other in the clad 60. This 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. In addition, 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.
In this optical fiber, the plurality of solid cores 52 having a high refractive index are arranged apart from each other in the clad 60. This optical fiber guides light in a state where the influence of optical wave coupling can be ignored by sufficiently reducing the optical wave coupling between the solid cores 52. Therefore, the solid core type multi-core optical fiber has an advantage that each core can be treated as an independent waveguide.
This optical fiber has a structure in which a plurality of hole structures and the core regions of (2) described above are arranged in the clad 60.
This optical fiber has a structure in which a plurality of hole structures of (3) described above are arranged in the clad 60.
This optical fiber has a structure in which a plurality of hole structures of (4) described above are arranged in the clad 60.
This optical fiber has a structure in which a plurality of coupling core structures of (5) described above are arranged in the clad 60.
A propagation mode in these optical fibers may be not only a single mode but also a multi-mode.
The light source 11a is a semiconductor light source such as a laser diode (LD) or a light emitting diode (LED), a light source using nonlinear optics as in the following reference, or a lamp light source. [Reference] USHIO website, https://www.ushio.co.jp/jp/technology/lightedge/200012/100236.html
An optical system 11b is, for example, a lens. The optical system 11b inputs the output light of each light source 11a into the optical fiber or core of the propagation section 50.
A propagation path 50a is a single fiber in the optical cable, or a single core in the multi-core optical fiber.
As shown in
In a case of this configuration, the number of light sources 11a is one. The light source 11a, the optical system 11b, and the transmission path 50a are the same as the light source, the optical system, and the transmission path described in
The light branching unit 11d branches the UV ray output from the light source 11a and enters the plurality of optical systems 11b.
As shown in
The supply section 51 transmits UV ray to the irradiation unit 13. The supply section 51 is a single-core optical fiber, has a simple configuration and is excellent in economic efficiency, and is thin and thus can be laid in a narrow space. The optical fiber described in (1) to (5) of
The irradiation unit 13 irradiates a predetermined target site Ar to be sterilized with the UV ray transmitted through the optical cable or the multi-core optical fiber. The irradiation unit 13 includes an optical system such as a lens designed for a wavelength in the ultraviolet region.
With the configuration stated above, the ultraviolet light irradiation system 301 can reduce deterioration over time of transmission loss characteristics of the optical fiber due to UV rays and prevent a decrease in UV ray irradiation power.
The ultraviolet light irradiation system 301 further includes: the photosynthesis distribution unit 16 configured to divide the ultraviolet rays subjected to space-division multiplexing and propagated through the propagation section 50 into N groups, and to multiplex the ultraviolet rays for each group to input the rays to the N single-core optical fibers, provided between the propagation section 50 and the supply section 51 in a case where N>2.
In the present embodiment, only a configuration different from the ultraviolet light irradiation system 301 described in
With the configuration stated above, the ultraviolet light irradiation system 302 can reduce deterioration over time of transmission loss characteristics of the optical fiber due to UV rays and prevent a decrease in UV ray irradiation power. The ultraviolet light irradiation system 302 can irradiate a plurality of decontamination sites with UV rays from the single ultraviolet light source unit, leading to economic advantages.
With the configuration stated above, the ultraviolet light irradiation system 303 can reduce deterioration over time of transmission loss characteristics of the optical fiber due to UV rays and prevent a decrease in UV ray irradiation power. The ultraviolet light irradiation system 303 can irradiate a plurality of decontamination sites with UV rays from the single ultraviolet light source unit, leading to economic advantages.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/008270 | 3/3/2021 | WO |
