Lighting systems for plant cultivation, shelves for plant cultivation racks, plant cultivation racks, and plant cultivation factories

Abstract

The present invention provides a light source system for plant cultivation, shelves for plant cultivation racks, plant cultivation racks, and a plant cultivation factory, all of which are capable of suppressing the deterioration of components constituting the light source system. [Solution] The plant growth light source system 10 comprises a support 20, a plant growth light source 30 positioned on the support 20, and an ultraviolet light source 40 positioned on the support 20. The ultraviolet light source 40 is positioned closer to the plant than the plant growth light source 30.

Description

Technical Field

[0001] The present disclosure relates to a light source system for plant cultivation, a shelf board for a plant cultivation shelf, a plant cultivation shelf, and a plant cultivation factory.

Background Art

[0002] As a lighting device used in a plant cultivation factory, in recent years, instead of conventional fluorescent lamps and high-pressure sodium lamps, etc., the demand for lighting devices using LEDs with low power consumption as a light source has been expanding.

[0003] As an example of a plant cultivation factory using a lighting device with an LED as a light source, an LED lighting device for plant cultivation has been proposed (see, for example, Patent Document 1). This LED lighting device forms a planar light source by arranging a plurality of LED chips on a flexible type circuit board.

[0004] Also, it is known that pests and diseases can be suppressed by irradiating plants with light containing UV-B (wavelength range of 280 nm to 315 nm) (see, for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] It is conceivable to arrange a UV-B light source that irradiates ultraviolet light having a UV-B wavelength in a lighting device in which a plurality of light sources for plant cultivation are arranged. However, in this case, there is a risk that the components constituting the lighting device are likely to deteriorate due to the ultraviolet light from the UV-B light source.

[0007] This disclosure provides a light source system for plant cultivation, a shelf board for a plant cultivation shelf, a plant cultivation shelf, and a plant cultivation factory, all of which are capable of suppressing the deterioration of components constituting the light source system. [Means for solving the problem]

[0008] Embodiments of this disclosure relate to the following [1] to [9].

[0009] [1] A light source system for plant growth, comprising a support, a plant growth light source disposed on the support, and an ultraviolet light source disposed on the support, wherein the ultraviolet light source is located closer to the plant than the plant growth light source.

[0010] [2] The light source for plant growth according to [1], wherein the ultraviolet light source is attached to the support via a mounting substrate on which the ultraviolet light source is mounted.

[0011] [3] The plant growing light source system according to [2], wherein the thickness of the mounting substrate is 3 mm or more.

[0012] [4] The light source system for plant growth according to [2] or [3], wherein the mounting substrate is detachably attached to the support.

[0013] [5] The ultraviolet light source irradiates ultraviolet light with a wavelength of 280 nm or more and 320 nm or less, a light source system for plant cultivation according to any one of [1] to [4].

[0014] [6] A plant growing light source system according to any one of [1] to [5], wherein the irradiation time of light from the plant growing light source and the irradiation time of light from the ultraviolet light source can be controlled to be different from each other.

[0015] [7] A shelf for a plant growing rack, comprising a substrate and a light source system for plant growing according to any one of claims [1] to [6], attached to the substrate.

[0016] [8] A plant cultivation shelf comprising a shelf board, wherein the shelf board is provided with the light source system for plant cultivation according to any one of [1] to [6] on the lower surface side of the substrate, the plant cultivation shelf.

[0017] [9] A plant cultivation factory comprising a building and the plant cultivation shelf according to [8] disposed inside the building.

Advantages of the Invention

[0018] According to the present embodiment, deterioration of components constituting the light source system can be suppressed.

Brief Description of the Drawings

[0019] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a light source system according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view (an enlarged view of part II in FIG. 1) showing a light source system according to an embodiment. [Figure 3] FIG. 3 is a schematic perspective view showing a plant cultivation factory according to an embodiment. [Figure 4] FIG. 4 is a schematic perspective view showing a plant cultivation shelf according to an embodiment. [Figure 5] FIG. 5 is a diagram showing a measurement example of the intensity of ultraviolet rays in the light source system.

Embodiments for Carrying Out the Invention

[0020] The light source system for plant cultivation according to the present embodiment includes a support, a light source for plant cultivation disposed on the support, and an ultraviolet light source disposed on the support. The ultraviolet light source is located closer to the plant side than the light source for plant cultivation.

[0021] In the plant cultivation light source system according to this embodiment, the ultraviolet light source is located closer to the plants than the plant cultivation light source. Therefore, ultraviolet rays from the ultraviolet light source do not substantially reach the plant cultivation light source. This suppresses the degradation of the support and components constituting the plant cultivation light source by ultraviolet rays.

[0022] Hereinafter, one embodiment will be described in detail with reference to the drawings. The following figures are schematic representations. Therefore, the size and shape of each part are exaggerated as appropriate to facilitate understanding. Furthermore, it is possible to modify and implement the design as appropriate without departing from the technical concept. In the following figures, the same parts are denoted by the same reference numerals, and some detailed explanations may be omitted. In addition, the numerical values ​​such as dimensions and material names of each component described in this specification are examples of embodiments and are not limiting, and can be selected and used as appropriate. In this specification, terms that specify shapes and geometric conditions, such as parallel, orthogonal, and perpendicular, are used not only in their strict sense but also to include substantially the same state.

[0023] (Light source system for plant cultivation) The plant cultivation light source system 10 (hereinafter also referred to as "light source system 10") according to this embodiment, as shown in Figure 1, is installed in a plant cultivation factory 90 (Figure 3) using artificial light, as will be described later, to cultivate plants. Such a light source system 10 comprises a support 20, a plant cultivation light source 30, and an ultraviolet light source 40. The plant cultivation light source 30 and the ultraviolet light source 40 are each arranged on the support 20. The ultraviolet light source 40 is located closer to the plants than the plant cultivation light source 30.

[0024] The light source system 10 according to this embodiment may be a sheet-shaped lighting device. A sheet-shaped lighting device can have a thin overall thickness. Therefore, the vertical spacing between the shelves of the plant cultivation rack can be narrowed, thereby improving the yield per unit floor area of ​​the plant cultivation factory.

[0025] As shown in Figure 1, the light source system 10 has plant growth light sources 30 arranged on its light-emitting surface 11 side (the side facing the plants when in use). By using such a direct-type light source system 10, the light emitted from the plant growth light sources 30 reaches the plants directly below the light-emitting surface 11, thus increasing the light intensity and promoting plant growth. In addition, the overall thickness of the sheet can be reduced to minimize shadows cast on the sides of the plant growth light sources 30. Furthermore, by using a flexible wiring board as the support 20, a light source system 10 with a relatively large sheet surface area can be obtained. Generally, in plant cultivation factories and plant cultivation shelves, multiple light source systems 10 are used in an arrangement, but if the positions of adjacent light source systems 10 are scattered, variations in light intensity may occur, potentially reducing plant yield. A light source system 10 with a relatively large sheet surface area can reduce the number of light source systems 10 used. Therefore, variations in light intensity caused by the arrangement of multiple light source systems 10 can be suppressed. In this embodiment, an example of a light source system 10 equipped with a flexible wiring board as the support 20 is shown, but the system is not limited to this, and a light source system equipped with a rigid wiring board may also be used. A light source system equipped with a rigid wiring board has high resistance to stress and is less prone to damage.

[0026] The plant growth light sources 30 may be arranged in a grid pattern in a plan view within the support 20. For example, the plant growth light sources 30 may be arranged in a multi-stage multi-row matrix, and multiple rows of plant growth light sources 30 connected in series may be arranged. Specifically, it is preferable to arrange 10 to 14 plant growth light sources 30 in series in a first arrangement direction, and to arrange 4 to 10 rows of these rows in parallel in a second arrangement direction of the plant growth light sources 30. By arranging 10 or more plant growth light sources 30 in series, the plant growth light sources 30 can be arranged at short intervals along the first arrangement direction. This makes it possible to suppress in-plane variations in illuminance of the light source system 10 and to suppress variations in the light irradiated onto plants. By arranging 14 or fewer plant growth light sources 30 in series, power consumption can be reduced, and running costs such as utility costs in the plant growth factory can be reduced. By arranging four or more rows of plant growth light sources 30 in parallel in the second arrangement direction of the plant growth light sources 30, damage to a specific plant growth light source 30 can be prevented from spreading to other rows of plant growth light sources 30. This prevents an extreme decrease in the overall illuminance of the light source system 10. Furthermore, by limiting the range in which the illuminance of the light source system 10 decreases, the range in which defective products may occur can be limited, thereby suppressing a decrease in yield.

[0027] The spacing P between the plant growth light sources 30 may be 30 mm or more, or 37 mm or more. The spacing P between the plant growth light sources 30 may be 100 mm or less, or 50 mm or less. By setting the spacing between the plant growth light sources 30 within the above range, the brightness of the light source system 10 can be made uniform within the plane, suppressing variations in the light irradiated onto the plants. In addition, the power consumption of the light source system 10 can be reduced.

[0028] The arrangement of the plant growth light sources 30 is not limited to a grid-like pattern in plan view, but may also be arranged in a staggered pattern in plan view. The plant growth light sources 30 do not need to be uniformly arranged within the plane of the support 20. For example, the density of plant growth light sources 30 may be increased at the periphery of the support 20. This suppresses a decrease in the brightness of the light source system 10 at the periphery of the support 20, makes the brightness of the light source system 10 uniform within the plane, and suppresses variations in the light irradiated onto the plants.

[0029] The size and planar shape of the light source system 10 are not particularly limited. The overall shape of the light source system 10 may be rectangular in plan view. Because the light source system 10 offers a high degree of freedom in terms of size and shape, it can flexibly respond to various demands in this regard. Furthermore, taking advantage of its flexibility, it can be mounted on various shapes of mounting surfaces, not just flat ones.

[0030] As shown in Figure 1, the plant growth light source 30 is electrically connected to the first control unit 35. The first control unit 35 supplies power to the plant growth light source 30. The first control unit 35 also controls the light emission of the plant growth light source 30. The first control unit 35 is supplied with an AC voltage of any voltage, for example, 100V to 240V. The first control unit 35 converts the AC voltage of 100V to 240V into a constant voltage (for example, 44V) DC voltage. The first control unit 35 further dims the plant growth light source 30. The constant voltage output from the first control unit 35 is applied to the plant growth light source 30.

[0031] By appropriately adjusting the illuminance of the plant growth light source 30 in this way, the degree of plant growth can be adjusted according to the growth stage of the plant. For example, in the early stages of growth when the plant leaves are small, the illuminance of the plant growth light source 30 may be lowered. In the later stages of growth when the plant leaves are large, the illuminance of the plant growth light source 30 may be increased. Alternatively, in the early stages of growth when the plant is short, the distance between the plant and the plant growth light source 30 is greater, so the illuminance of the plant growth light source 30 may be increased. In the later stages of growth when the plant is taller, the distance between the plant and the plant growth light source 30 is closer, so the illuminance of the plant growth light source 30 may be lowered.

[0032] In this embodiment, the light source system 10 has an ultraviolet light source 40 on its light-emitting surface 11 side (plant side). Because the light source system 10 has an ultraviolet light source 40, ultraviolet (UV) light from the ultraviolet light source 40 reaches the plants. Ultraviolet light is generally classified into three types according to its wavelength range. Ultraviolet light is called UV-A (wavelength 320nm to 400nm), UV-B (wavelength 280nm to 320nm), and UV-C (wavelength 100nm to 280nm), from longest to shortest wavelength. By irradiating plants with ultraviolet light having a wavelength of UV-B (wavelength 280nm to 320nm), the resistance of the plants can be increased or the growth of pathogenic fungi can be suppressed. This can suppress the occurrence of diseases and pests on plants.

[0033] The ultraviolet light source 40 may be placed as a single unit within the support 20. In this case, the ultraviolet light source 40 may be placed in the central part of the support 20. The ultraviolet light source 40 may be placed between two adjacent plant growth light sources 30. Alternatively, multiple ultraviolet light sources 40 may be placed within the support 20 at intervals from each other.

[0034] The ultraviolet light source 40 is located closer to the plants than the plant growth light source 30. In other words, the ultraviolet light source 40 is located further from the support 20 than the plant growth light source 30. When we say that the ultraviolet light source 40 is located closer to the plants than the plant growth light source 30, it means that the light-emitting surface of the ultraviolet light source 40 is located closer to the plants than the light-emitting surface of the plant growth light source 30. Furthermore, if multiple plant growth light sources 30 are arranged, the plant growth light source 30 located closest to the plants is used for comparison. Similarly, if multiple ultraviolet light sources 40 are arranged, the ultraviolet light source 40 located closest to the plants is used for comparison. The distance L between the plant growth light source 30 and the ultraviolet light source 40 (distance in the thickness direction of the support 20) may be 3 mm or more, or 5 mm or more. By setting the distance L between the plant growth light source 30 and the ultraviolet light source 40 to 3 mm or more, the degradation of the support 20 and the components constituting the plant growth light source 30 due to ultraviolet light is suppressed. The distance L between the plant growth light source 30 and the ultraviolet light source 40 (distance in the thickness direction of the support 20) may be 30 mm or less, or 10 mm or less. By setting the distance L between the plant growth light source 30 and the ultraviolet light source 40 to 10 mm or less, the ultraviolet light source 40 can be prevented from getting too close to the plants.

[0035] As the ultraviolet light source 40, an LED chip that emits ultraviolet light may be used. The ultraviolet light source 40 emits ultraviolet light with a wavelength of UV-B (wavelength between 280 nm and 320 nm). The ultraviolet light source 40 may emit ultraviolet light of a single wavelength, such as 280 nm or 310 nm.

[0036] The ultraviolet light source 40 is mounted on the mounting substrate 41. The ultraviolet light source 40 is attached to the support 20 via the mounting substrate 41. The mounting substrate 41 has an insulating portion and a conductive portion. The conductive portion of the mounting substrate 41 electrically connects the ultraviolet light source 40 and the second control unit 45, which will be described later.

[0037] The thickness T of the mounting substrate 41 may be 3 mm or more, or 5 mm or more. By setting the thickness T of the mounting substrate 41 to 3 mm or more, degradation of the components constituting the support 20 and the plant growth light source 30 due to ultraviolet light is suppressed. The thickness T of the mounting substrate 41 may be 30 mm or less, or 10 mm or less. By setting the thickness T of the mounting substrate 41 to 30 mm or less, the ultraviolet light source 40 is prevented from coming too close to the plants.

[0038] The mounting board 41 may be detachably attached to the support 20. For example, the mounting board 41 may have claws and the support 20 may have openings. In this case, the mounting board 41 can be detachably attached to the support 20 by the claws of the mounting board 41 engaging with the openings in the support 20. This allows the ultraviolet light source 40 to be removed from the support 20 as a single unit and replaced with a new one when it stops working due to its lifespan or malfunction.

[0039] As shown in Figure 1, the ultraviolet light source 40 is electrically connected to the second control unit 45. The second control unit 45 supplies power to the ultraviolet light source 40 via the mounting board 41 and controls the emission of light from the ultraviolet light source 40. The second control unit 45 is supplied with an AC voltage of any voltage, for example, 100V to 240V. The second control unit 45 converts the AC voltage of 100V to 240V into a constant voltage (for example, 44V) DC voltage. The second control unit 45 further dims the ultraviolet light source 40. The constant voltage output from the second control unit 45 is applied to the ultraviolet light source 40.

[0040] The second control unit 45, which controls the ultraviolet light source 40, can be controlled independently of the first control unit 35, which controls the plant growth light source 30. In other words, the second control unit 45 and the first control unit 35 have independent power supply systems. In this case, the irradiation time of light from the plant growth light source 30 and the irradiation time of ultraviolet light from the ultraviolet light source 40 can be controlled to be different from each other. For example, depending on the type of plant, the time period during which light is irradiated from the plant growth light source 30 and the time period during which ultraviolet light is irradiated from the ultraviolet light source 40 may differ. In this case, by controlling the irradiation time of light from the plant growth light source 30 and the irradiation time of ultraviolet light from the ultraviolet light source 40 to be different from each other, it becomes possible to irradiate the plants appropriately according to the plants being cultivated.

[0041] By appropriately adjusting the illuminance of the ultraviolet light source 40, the degree of disease control for the plants can be adjusted according to the growth stage of the plants. For example, in the early stages of growth when the plant leaves are small, the illuminance of the ultraviolet light source 40 may be lowered. In the later stages of growth when the plant leaves are large, the illuminance of the ultraviolet light source 40 may be increased. Alternatively, in the early stages of growth when the plant is short, the distance between the plant and the ultraviolet light source 40 is greater, so the illuminance of the ultraviolet light source 40 may be increased. In the later stages of growth when the plant is taller, the distance between the plant and the ultraviolet light source 40 is closer, so the illuminance of the ultraviolet light source 40 may be lowered.

[0042] (Each component of the light source system) Next, the components constituting the light source system 10 will be described. As shown in Figure 2, the light source system 10 comprises a support 20 and a plant growth light source 30 disposed on the support 20. The support 20 has a flexible wiring substrate 21, a metal wiring section 22, a light-reflecting layer 23, and a protective layer 24. The metal wiring section 22 is formed on the surface (plant-facing side) of the wiring substrate 21. The light-reflecting layer 23 is formed on the surface (plant-facing side) of the metal wiring section 22. The protective layer 24 is formed on the surface (plant-facing side) of the light-reflecting layer 23.

[0043] The plant growth light source 30 is mounted in a manner that allows electrical conductivity to the metal wiring section 22. In this light source system 10, since the plant growth light source 30 is mounted on the support 20, it is possible to arrange multiple plant growth light sources 30 at a desired high density.

[0044] A light-reflecting layer 23 is formed to cover the area of ​​the light source system 10, excluding the area where the plant growth light source 30 is installed and its surrounding area. The light-reflecting layer 23 is positioned to cover the metal wiring section 22. The light-reflecting layer 23 is a layer that combines an insulating function that contributes to improving the migration resistance characteristics of the light source system 10 and a light-reflecting function that contributes to improving the light environment created by the light source system 10. The light-reflecting layer 23 may be formed from an insulating resin composition containing a white pigment. If the migration resistance characteristics and light-reflecting function can be obtained with only the aforementioned metal wiring section 22 and the protective layer 24 described later, a structure without the light-reflecting layer 23 is also possible.

[0045] A protective layer 24 is provided that covers the light-reflecting layer 23 and the plant-growing light source 30, and protects the plant-growing light source 30. The protective layer 24 is a resinous film formed on the outermost surface (the surface closest to the light-emitting surface 11) of the light source system 10, primarily to ensure the waterproofness of the light source system 10. The protective layer 24 according to this embodiment may be formed, for example, by a method of spraying a transparent resin composition (hereinafter referred to as the "spray coating method") or by a method of curtain coating.

[0046] Each plant growth light source 30 is electrically connected to the metal wiring section 22. Alternatively, the plant growth light sources 30 may be mounted on the metal wiring section 22 via a conductive resin.

[0047] (Wiring board) A flexible resin film may be used as the wiring board 21. In this specification, "flexible" means "able to be bent to a radius of curvature of at least 1 m, preferably 50 cm, more preferably 30 cm, even more preferably 10 cm, and particularly preferably 5 cm."

[0048] As the material for the wiring board 21, a thermoplastic resin with high heat resistance and insulation properties may be used. As such a resin, polyimide resin (PI) or polyethylene naphthalate (PEN), which has excellent heat resistance, dimensional stability when heated, mechanical strength, and durability, can be used. In particular, polyethylene naphthalate (PEN) whose heat resistance and dimensional stability have been improved by heat resistance improvement treatment such as annealing, or polyimide resin (PI) which has heat resistance, insulation resistance, and mechanical strength can be preferably used. Alternatively, polyethylene terephthalate (PET) whose flame retardancy has been improved by adding flame-retardant inorganic fillers may also be used.

[0049] The thickness of the wiring board 21 is not particularly limited, but from the viewpoint of not becoming a bottleneck in the heat dissipation path, having heat resistance and insulation properties, and balancing manufacturing costs, it may be approximately 10 μm to 500 μm, preferably 50 μm to 250 μm. Furthermore, from the viewpoint of maintaining good productivity when manufacturing by a roll-to-roll method, it is preferable that the thickness be within the above range.

[0050] (Metal wiring part) The metal wiring section 22 is a wiring pattern formed on the surface (plant-facing side) of the wiring board 21 using a conductive substrate such as metal foil. Preferably, the metal wiring section 22 is formed on the surface of the wiring board 21 by a dry lamination method. Preferably, the metal wiring section 22 achieves a high level of both heat dissipation and electrical conductivity, and for example, copper foil can be used. In this case, the heat dissipation from the plant growth light source 30 is stable and the increase in electrical resistance is prevented, so the variation in light emission between plant growth light sources 30 is reduced and stable light emission is possible. In addition, the lifespan of the plant growth light source 30 is extended. Furthermore, deterioration of surrounding components such as the wiring board 21 due to heat is prevented, so the product lifespan of the light source system 10 can also be extended. Examples of metals that can be used to form the metal wiring section 22 include, in addition to the above-mentioned copper, aluminum, gold, silver, and other metals.

[0051] The thickness of the metal wiring section 22 can be appropriately set according to the current resistance required for the support 20. However, in order to suppress warping due to thermal shrinkage of the wiring board 21 during soldering by reflow soldering or the like, it is preferable that the thickness of the metal wiring section 22 be 10 μm or more. On the other hand, it is preferable that the thickness of the metal wiring section 22 be 50 μm or less, which allows for sufficient flexibility of the support 20 and prevents a decrease in handling performance due to increased weight.

[0052] (Light source for plant growth) LED chips may be used as the plant growth light source 30. The plant growth light source 30 emits visible light with a wavelength of 380 nm to 780 nm. It is preferable to select a plant growth light source 30 with high luminous efficiency. Specifically, it is preferable to use a plant growth light source 30 with a luminous efficiency of 150 lm / W or more, and it is even more preferable to use one with a luminous efficiency of 180 lm / W or more. By increasing the luminous efficiency of the plant growth light source 30 to 150 lm / W or more, the number (density) of plant growth light sources 30 can be reduced, the heat generated by Joule heating from the plant growth light source 30 can be reduced, and variations in plant growth due to heat from the plant growth light source 30 can be reduced, thereby suppressing a decrease in yield.

[0053] As described above, the light source system 10 directly mounts the plant growth light source 30 onto a metal wiring section 22 that exhibits high heat dissipation. This allows the excess heat generated when the plant growth light source 30 is lit to be quickly dissipated through the metal wiring section 22, and the heat to be sufficiently dissipated to the outside of the light source system 10 via the wiring board 21, thereby reducing variations in plant growth caused by heat from the plant growth light source 30 and suppressing a decrease in yield.

[0054] By using LED chips as the plant growth light source 30, the height difference between areas where the plant growth light source 30 is located and areas where it is not located can be reduced. As a result, shadows on the sides of the plant growth light source 30 are less likely to occur. This suppresses variations in the amount of light irradiated onto the plants, even when the plants grow close to the plant growth light source 30. By suppressing variations in the amount of light irradiated onto the plants, the size and quality of the grown plants can be kept within a certain standard range, reducing the number of non-conforming products.

[0055] (light reflective layer) The light-reflecting layer 23 is a layer formed in areas excluding the region where the plant growth light source 30 is installed and its surrounding areas. The light-reflecting layer 23 is a so-called resist layer that improves the migration resistance characteristics of the support 20 by having sufficient insulating properties. The light-reflecting layer 23 is also a light-reflecting layer that has light reflectivity that contributes to improving the luminescence brightness of the light environment created by the light source system 10.

[0056] The light-reflecting layer 23 can be formed from various resin compositions that use a urethane-based resin or the like as a base resin and further contain a white pigment made of an inorganic filler such as titanium dioxide. As the base resin of the resin composition used to form the light-reflecting layer 23, in addition to urethane-based resins, acrylic polyurethane resins, polyester resins, phenolic resins, etc. can be used as appropriate. It is more preferable that the base resin of the resin composition forming the light-reflecting layer 23 be the same as or of the same type as the resin composition forming the protective layer 24. As for the protective layer 24, it is preferable to use an acrylic polyurethane resin as the main material resin, as will be described later. Therefore, if the base resin of the resin composition forming the protective layer 24 is an acrylic polyurethane resin, it is more preferable that the base resin of the resin composition for forming the light-reflecting layer 23 be a urethane-based resin or an acrylic polyurethane resin.

[0057] As an inorganic filler to be included as a white pigment in the resin composition that forms the light-reflecting layer 23, in addition to titanium dioxide, at least one selected from alumina, barium sulfate, magnesia, aluminum nitride, boron nitride, barium titanate, kaolin, talc, calcium carbonate, zinc oxide, silica, mica powder, glass powder, nickel powder, and aluminum powder can be used.

[0058] The thickness of the light-reflecting layer 23 is 5 μm or more and 50 μm or less, more preferably 7 μm or more and 20 μm or less. By making the thickness of the light-reflecting layer 23 5 μm or more, the risk of the light-reflecting layer 23 becoming too thin can be reduced, especially at the edges of the metal wiring portion 22. On the other hand, from the viewpoint of maintaining the light-reflecting layer 23 from bending of the substrate during handling and transport, the thickness of the light-reflecting layer 23 is preferably 50 μm or less.

[0059] Furthermore, the light-reflecting layer 23 preferably has an average light reflectance of 65% or more at wavelengths of 400 nm to 780 nm, more preferably 70% or more, and even more preferably 80% or more. For example, by including 20 parts by mass or more of titanium dioxide per 100 parts by mass of a urethane-based or acrylic polyurethane base resin, it is possible to achieve a light reflectance of 75% or more for the light-reflecting layer 23 when its thickness is 8 μm.

[0060] (protective layer) The protective layer 24 is formed on the outermost surface of the light source system 10 so as to cover the plant growth light source 30. The protective layer 24 covers multiple plant growth light sources 30 together and extends continuously between adjacent plant growth light sources 30. The protective layer 24 is waterproof and transparent. The waterproof nature of the protective layer 24 prevents water from entering the inside of the device when the light source system 10 is used as a plant growth light source. In addition, the protective layer 24 prevents the plant growth light sources 30 from detaching from the light source system 10.

[0061] The protective layer 24 can be formed from various resin compositions using acrylic polyurethane resin or the like as the base resin. For example, the protective layer 24 may be formed from a two-component curable acrylic polyurethane resin containing fluorine. As the base resin of the resin composition used to form the protective layer 24, in addition to acrylic polyurethane resin, urethane resin, polyester resin, phenolic resin, etc. can be used as appropriate. It is more preferable that the base resin of the resin composition forming the protective layer 24 be the same as or of the same type as the resin composition forming the light-reflecting layer 23. A preferred specific combination is one in which the base resin of the resin composition forming the light-reflecting layer 23 is a urethane resin, and the same resin forming the protective layer 24 is an acrylic polyurethane resin.

[0062] The protective layer 24 covers at least a portion of the plant growth light source 30, protecting it. This prevents the plant growth light source 30 from detaching from the wiring board 21 even if workers or others come into contact with it in the plant cultivation factory. As a result, it prevents the plant growth light source 30 from falling onto the plants being cultivated and prevents it from coming into contact with the plants. This helps maintain good hygiene for the plants being cultivated.

[0063] (Plant cultivation factory and plant cultivation shelves) Figure 3 is a schematic diagram showing the configuration of a plant cultivation factory 90 using the light source system 10 according to this embodiment. The plant cultivation factory 90 comprises a building 91 and a plurality of plant cultivation shelves 80 arranged inside the building 91.

[0064] As shown in Figure 4, the plant cultivation shelf 80 has a plurality (4) of support pillars 82 and a plurality of substrates 81 arranged vertically at intervals along the support pillars 82. The upper surface of each substrate 81, except for the uppermost substrate 81, is provided with a growing medium area for cultivating plant PL. The lower surface of each substrate 81, except for the lowermost substrate 81, forms a ceiling surface relative to the substrate 81 located below it, and a light source system 10 is arranged in parallel. Furthermore, the substrate 81 and the light source system 10 attached to the lower surface of the substrate 81 constitute a shelf board 83 for the plant cultivation shelf. Alternatively, the substrate 81 and the light source system 10 attached to the lower surface of the substrate 81 constitute a shelf board 83 for the plant cultivation shelf. In this embodiment, we also provide such a shelf board 83 for the plant cultivation shelf (Figure 4), a plant cultivation shelf 80 (Figure 4), and a plant cultivation factory 90 (Figure 3) equipped with the plant cultivation shelf 80.

[0065] (Operation of this embodiment) Next, we will describe the operation of this embodiment, which has the above configuration.

[0066] First, the plant growth light source 30 is turned on by supplying electricity from the first control unit 35. The light from the plant growth light source 30 reaches the plants located below the plant growth light source 30, promoting plant growth. Also, the ultraviolet light source 40 is turned on by supplying electricity from the second control unit 45. The ultraviolet light from the ultraviolet light source 40 reaches the plants located below the ultraviolet light source 40. The ultraviolet light increases the resistance of plants or suppresses the growth of pathogenic fungi. This helps to suppress the occurrence of pests and diseases on plants. In this way, by using the light source system 10 according to this embodiment, it is possible to promote plant growth while suppressing the occurrence of pests and diseases on plants. This makes it possible to obtain good yields of plants. The time periods when the plant growth light source 30 is turned on and the time periods when the ultraviolet light source 40 is turned on may be controlled independently of each other. The plant growth light source 30 and the ultraviolet light source 40 may be turned on simultaneously, or they may be turned on at different time periods.

[0067] Incidentally, ultraviolet light is generally known to degrade resins. In this case, for example, the physical properties of the resin, such as its inherent mechanical and electrical properties, may decrease, or the resin may undergo changes in appearance such as discoloration. For this reason, it is conceivable that after a certain period of time, the ultraviolet light from the ultraviolet light source 40 may degrade each component constituting the light source system 10. Specifically, the ultraviolet light from the ultraviolet light source 40 may degrade resins such as the sealing resin contained in the plant growth light source 30, the support 20, the light reflection layer 23, and the protective layer 24. If these resins degrade, for example, the amount of light emitted by the plant growth light source 30 may decrease, and it may become impossible to grow plants sufficiently.

[0068] In contrast, in this embodiment, the ultraviolet light source 40 is located closer to the plants than the plant growth light source 30. Because the ultraviolet light source 40 has high directivity, the ultraviolet rays from the ultraviolet light source 40 hardly irradiate the support 20 side of the light-emitting surface of the ultraviolet light source 40. Therefore, by positioning the ultraviolet light source 40 closer to the plants than the plant growth light source 30, the ultraviolet rays from the ultraviolet light source 40 are suppressed from reaching the plant growth light source 30, the support 20, the light-reflecting layer 23, and the protective layer 24, etc. This suppresses the deterioration of each component such as resin that makes up the light source system 10 by the ultraviolet rays from the ultraviolet light source 40. As a result, the decrease in the amount of light irradiated by the plant growth light source 30 due to the deterioration of the resin and other components that make up the light source system 10 is suppressed, and the inability to sufficiently grow plants is suppressed.

[0069] In this embodiment, the ultraviolet light source 40 may also be attached to the support 20 via a mounting substrate 41 on which the ultraviolet light source 40 is mounted. This allows the ultraviolet light source 40 to be positioned closer to the plant than the plant growth light source 30 by using the mounting substrate 41 on which the ultraviolet light source 40 is mounted. In this case, there is no need to use other components to position the ultraviolet light source 40 closer to the plant than the plant growth light source 30.

[0070] Furthermore, in this embodiment, the thickness of the mounting substrate 41 may be 3 mm or more. This ensures sufficient distance in the thickness direction of the mounting substrate 41 between the plant growth light source 30 and the ultraviolet light source 40. As a result, degradation of the components constituting the light source system 10 due to ultraviolet light can be suppressed more effectively.

[0071] In this embodiment, the mounting substrate 41 may be detachably attached to the support 20. This allows the ultraviolet light source 40 to be easily replaced with a new one when the chip of the ultraviolet light source 40 reaches the end of its lifespan or malfunctions.

[0072] In this embodiment, the ultraviolet light source 40 may also irradiate ultraviolet light with a wavelength of 280 nm to 320 nm. This allows the ultraviolet light source 40 to irradiate the plants with ultraviolet light, thereby suppressing the occurrence of diseases and pests on the plants.

[0073] In this embodiment, the irradiation time from the plant growth light source 30 and the irradiation time from the ultraviolet light source 40 may be controlled to be different from each other. This allows for appropriate adjustment of the irradiation time from the plant growth light source 30 and the irradiation time from the ultraviolet light source 40 depending on the type of plant, etc.

[0074] The plant cultivation shelf 83, plant cultivation shelf 80, and plant cultivation factory 90 according to this embodiment are equipped with a plant cultivation light source system 10 according to this embodiment. This makes it possible to obtain plants with good yields and to suppress the deterioration of the components constituting the light source system 10 due to ultraviolet light.

[0075] [Examples] Next, we will describe the results of measuring the ultraviolet intensity from an ultraviolet light source in an actual light source system.

[0076] First, a light source system 10, as shown in Figure 5, was prepared. In Figure 5, an ultraviolet light source 40 was attached to the support 20 via a mounting substrate 41. As the ultraviolet light source 40, an LED light source (bare chip manufactured by DOWA Electronics Co., Ltd.) that emits ultraviolet light with a wavelength of 308 nm was used. The thickness T of the mounting substrate 41 was 7 mm. Next, the intensity of ultraviolet light from the ultraviolet light source 40 was measured below and around the ultraviolet light source 40. The intensity of ultraviolet light was measured using a digital UV irradiometer (digital ultraviolet intensity meter manufactured by Solar Meter Co., Ltd.) with a sensitivity wavelength of 280 nm to 320 nm. The results are shown in Figure 5.

[0077] In Figure 5, the numerical values ​​represent the ultraviolet intensity measured at that location (unit: μW / cm²). 2 This shows that, for example, at a position 15 cm away vertically below (towards the plant) the ultraviolet light source 40, the intensity of ultraviolet light is 44.5 μW / cm². 2 Furthermore, at a position 15 cm away directly to the side of the ultraviolet light source 40, the intensity of ultraviolet light was 0.4 μW / cm². 2 In contrast, at a position above the ultraviolet light source 40 (opposite the plant), the intensity of ultraviolet light was 0.0 μW / cm². 2 As is clear from this, when the ultraviolet light source 40 is located closer to the plants than the plant growth light source 30, the ultraviolet light from the ultraviolet light source 40 does not substantially reach the plant growth light source 30. Therefore, it is possible to suppress the deterioration of the components constituting the light source system 10 due to ultraviolet light from the ultraviolet light source 40.

[0078] The multiple components disclosed in the above embodiments and variations can be combined as needed. Alternatively, some components may be removed from all the components shown in the above embodiments and variations. [Explanation of Symbols]

[0079] 10 Light Source Systems 11. Light-emitting surface 20 Support 21 Wiring board 22 Metal wiring section 23 Light reflective layer 24 Protective layer 30 Light source for plant growth 35 First Control Unit 40 UV light source 41 Implemented circuit board 45 Second Control Unit 80 Plant growing shelves 81 circuit boards 82 Pillar 83 shelves 90 Plant cultivation factory 91 Buildings

Claims

1. A light source system for plant cultivation, Support and A plant growth light source arranged on the support, The support is provided with an ultraviolet light source arranged on the support, The aforementioned ultraviolet light source is located closer to the plants than the aforementioned plant growth light source, in a plant growth light source system.

2. The light source for plant cultivation according to claim 1, wherein the ultraviolet light source is attached to the support via a mounting substrate on which the ultraviolet light source is mounted.

3. The plant cultivation light source system according to claim 2, wherein the thickness of the mounting substrate is 3 mm or more.

4. The light source system for plant cultivation according to claim 2, wherein the mounting substrate is detachably attached to the support.

5. The light source for plant cultivation according to claim 1, wherein the ultraviolet light source irradiates ultraviolet light with a wavelength of 280 nm or more and 320 nm or less.

6. The plant cultivation light source system according to claim 1, wherein the irradiation time of light from the plant cultivation light source and the irradiation time of ultraviolet light from the ultraviolet light source can be controlled to be different from each other.

7. A shelf board for plant growing shelves, circuit board and A shelf board for a plant growing shelf, comprising a light source system for plant cultivation according to any one of claims 1 to 6, which is attached to the substrate.

8. It is a plant growing shelf, Equipped with shelves, The shelf is a plant growing shelf equipped with a light source system for plant cultivation according to any one of claims 1 to 6, which is attached to the lower side of the substrate.

9. The building and A plant cultivation factory comprising a plant cultivation shelf according to claim 8, located inside the aforementioned building.

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