JP6023405B2 - Daylighting device for plant factory and plant growing method - Google Patents

Description

  The present invention relates to a daylighting apparatus for a plant factory and a plant growing method.

  In recent years, for the stable supply of food, the development of closed plant factories that grow plants by controlling the plant growth environment has been progressing (see, for example, Patent Document 1). However, in such a closed plant factory, an artificial light source such as a fluorescent lamp is used as a light source for irradiating the plant. However, the lighting cost is high, and further, it is consumed due to artificial light source cultivation. There was a problem that the impression of the person was not so good.

  On the other hand, for example, a technique for guiding sunlight through an optical duct and irradiating the sunlight guided into a closed plant factory is known (see, for example, Patent Document 2).

JP-A-5-85134 JP 2004-97172 A

  However, in the method of guiding the sunlight into the closed plant factory using the optical duct as in Patent Document 2 described above, the sunlight taken in the optical duct is reflected a plurality of times. There was a problem that the amount of sunlight contained was attenuated, resulting in insufficient plant growth.

  An object of the present invention is to provide a daylighting device for plant factories capable of growing plants efficiently and efficiently at low cost. Another object of the present invention is to provide a plant growing method using such a daylighting apparatus.

  As a result of diligent research to achieve the above object, the present inventors have found that, in a conventional optical duct such as the optical duct described in Patent Document 2 described above, the sunlight that has been taken in is multiple times within the optical duct. When reflecting, the attenuation of light in a specific wavelength region is large, and as a result, the growth of plants is insufficient, and by preventing the attenuation of light in such a specific wavelength region It has been found that the above problems can be solved, and the present invention has been completed based on such knowledge.

That is, according to the present invention, there is provided a daylighting device for a plant factory having a daylighting unit that takes in natural light and a light emitting unit that irradiates the plant factory with light taken from the daylighting unit, and is silver or silver A vertical light guide portion that is formed by being surrounded by a light reflection plate having a light reflection layer made of an alloy as an inner surface and that extends in a vertical direction from the daylighting portion to guide light taken from the daylighting portion ; and silver or a light reflective layer of silver alloy formed surrounded by the light reflecting plate having an inner surface, at Rukoto connected to the lower end of the vertical light guide portion, the light from the vertical light guide portion to the light radiation portion A light reflecting layer made of silver or a silver alloy on the inner surface, and the light taken in from the daylighting portion is reflected at least once by the light reflecting layer, and then the light emitting portion From inside the plant factory, and from the light emission part into the plant factory. Lighting device for a plant factory percentage of photons in the near-infrared region of wavelength 700~1000nm during light is characterized in that 60% or more is provided.
The bent portion of the lighting device of the present invention has a first bent portion whose one end is connected to the lower end of the vertical light guide portion, and a horizontal portion whose one end is connected to the other end of the first bent portion and extends in the horizontal direction. A light guide part, a second bent part having one end connected to the other end of the horizontal light guide part, and connected to the other end of the second bent part, and extending in a vertical direction toward the light emitting part. And a second vertical light guide.

  In the daylighting device of the present invention, it is preferable that a diffusion plate for diffusing the light taken from the daylighting unit is provided in the light emitting unit.

Further, according to the present invention, there is provided a method for growing a plant in a plant factory using a daylighting device capable of taking natural light and irradiating the taken light into the plant factory, wherein the daylighting device is silver Alternatively, a vertical light guide unit that is formed by being surrounded by a light reflection plate with a light reflection layer made of a silver alloy as an inner surface, and that extends in a vertical direction from the daylighting unit, and that guides light taken from the daylighting unit; , a light reflecting layer made of silver or a silver alloy is formed surrounded by the light reflecting plate having an inner surface, said at Rukoto connected to the lower end of the vertical light guide portion, the light from the vertical light guide portion light radiation It possesses a bent portion leading to parts, and a light incorporated into the inside the lighting device, to after being reflected at least once by the light reflecting layer, in said plant factory, near-infrared wavelengths 700~1000nm It is characterized by irradiating natural light with a photon ratio of 60% or more Method for growing a plant is provided that.

  ADVANTAGE OF THE INVENTION According to this invention, the lighting apparatus for plant factories which can grow a plant favorably and efficiently at low cost can be provided.

FIG. 1 is a schematic diagram illustrating the overall configuration of a plant factory according to the present embodiment. FIG. 2 is a diagram illustrating a configuration of a reflecting plate included in the daylighting apparatus according to the embodiment. FIG. 3A and FIG. 3B are diagrams illustrating the configuration of the daylighting device used in the example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram illustrating the overall configuration of a plant factory 1 according to the present embodiment. As shown in FIG. 1, a plant factory 1 according to the present embodiment is a plant factory that uses, for example, a frozen container, an empty store, an abandoned factory, etc. as a closed space, and irradiates the plant factory 1 with sunlight. The lighting device 10 is provided.

  The daylighting apparatus 10 takes in sunlight from the daylighting port 11, and reflects the taken-in light by a light reflection layer (a light reflection layer will be described later) formed on the inner surface of the daylighting apparatus 10, while the daylighting apparatus 10 10 is configured to irradiate the plant factory 1 with the light guided and guided to the inside of the plant factory 1. And as shown in FIG. 1, the light from each light emission port 12 will be irradiated to the cultivation container 20 in which the plant 30 installed in the plant factory 1 was planted. In addition, as the plant factory 1, it can be used for any cultivation method of hydroponics and artificial soil cultivation. Moreover, as the lighting device 10, in order to take in sunlight efficiently, you may provide the sunlight tracking device for tracking sunlight, and condensing apparatuses, such as a condensing lens.

  The daylighting device 10 according to the present embodiment is formed by molding a light reflecting plate having a light reflecting layer on the inner layer into a predetermined shape, and the sun taken from the lighting port 11 by the light reflecting layer formed on the inner surface. Light is reflected. Moreover, the lighting port 11 and the light emission port 12 can be comprised with a highly transparent board which can permeate | transmit light, for example, a transparent glass plate or a transparent resin plate. Alternatively, the light emission port 12 may be an opening without providing such a highly transparent plate. The daylighting apparatus 10 has a bent portion as shown in FIG. 1, so that the sunlight taken in from the daylighting port 11 is provided on the inner surface of the daylighting apparatus 10 at least once, preferably twice or more. After being reflected by the formed light reflecting layer, the plant factory 1 is irradiated from the light exit 12.

  In the daylighting apparatus 10 of the present embodiment, a diffusion plate may be installed on the surface facing the light emission port 12, and the plant factory 1 is irradiated from the light emission port 12 by installing the diffusion plate. The light that is emitted can be made soft. Or in this embodiment, it may replace with a highly transparent board in the light emission port 12, and you may install a diffuser plate, and also in this case, the light irradiated in the plant factory 1 from the light emission port 12 is soft. Can be.

  Next, the light reflection plate constituting the daylighting apparatus 10 of the present embodiment will be described. FIG. 2 is a diagram showing a configuration of a light reflecting plate that constitutes the daylighting apparatus 10 of the present embodiment. As shown in FIG. 2, the light reflecting plate constituting the daylighting apparatus 10 of the present embodiment is formed by laminating the base 100, the resin layer 110, the light reflecting layer 120, and the protective layer 130 in this order. Yes. 2 is disposed in the daylighting apparatus 10 so that the light reflection layer 120 and the protective layer 130 are on the inner surface side.

  The base body 100 may be made of a material that can be processed into a desired shape, but in this embodiment, a metal plate is used in terms of excellent workability. Further, the metal plate constituting the substrate 100 is not particularly limited, and examples thereof include a steel plate, an aluminum plate, an aluminum alloy plate, etc. Among these, a steel plate is used in terms of improving mechanical strength and reducing manufacturing costs. Preferably used.

  Examples of the steel plate include an iron alloy plate having a chromium content of less than 11% by mass, or an iron alloy having a chromium content of 11% by mass or more, a so-called stainless steel plate. In particular, an iron alloy steel sheet having a chromium content of less than 11% by mass is an inexpensive material compared to aluminum and stainless steel, and is therefore suitable for widespread use of products.

  The aluminum alloy plate is mainly made of aluminum, and is alloyed by adding magnesium (Mg), manganese (Mn), silicon (Si) or the like in order to impart strength, workability, corrosion resistance, and the like.

  Further, the metal plate for constituting the base body 100 may be a surface-treated metal plate subjected to surface treatment. Examples of the surface-treated metal plate include those obtained by subjecting the surface of the metal plate to various platings, and those obtained by subjecting the surface of an aluminum plate to an alumite treatment.

  In the case where the substrate 100 is a plated metal plate surface-treated by plating, zinc, zinc alloy, tin, nickel, chromium, or the like can be used as a metal used for plating.

  For example, exemplifying and explaining a galvanized steel sheet obtained by forming zinc plating or zinc alloy plating on a steel sheet as the substrate 100, for example, a hot dip galvanized steel sheet, a hot dip galvanized steel sheet, There are a plurality of types such as an electrogalvanized steel sheet and an electrogalvanized steel sheet.

  Moreover, when forming zinc plating or zinc alloy plating on a steel plate, zinc or a zinc alloy is used as a metal used for plating. As the zinc alloy, zinc (Zn) containing 5-55 mass% aluminum (Al), zinc (Zn) containing cobalt (Co), molybdenum (Mo), or the like is used.

  Furthermore, the galvanized steel sheet may be subjected to chemical conversion treatment in order to prevent peeling or alteration of plating such as zinc. Examples of the chemical conversion treatment include chromate treatment, phosphate treatment, lithium-silicate treatment, silane coupling treatment, and zirconium treatment.

  Although the thickness of the base | substrate 100 is not specifically limited, Usually, it is 0.2-1 mm, Preferably it is 0.3-0.8 mm.

  The resin layer 110 is provided in order to improve the corrosion resistance of the base body 100 itself, and to improve the adhesion between the base body 100 and the light reflection layer 120 by being interposed between the base body 100 and the light reflection layer 120. The resin layer 110 can be a coating film or film made of various materials. The material of the coating film is not particularly limited as long as it is an organic resin material having good adhesion to the substrate 100. In particular, a polyester resin, an alkyd resin, an acrylic resin, and a two-component curing type A paint such as polyurethane resin is suitable. Examples of the film material include polyethylene, polycarbonate resin, polyamide resin, and polyimide resin. When the resin layer 110 is formed of a paint film, it can be formed on the substrate 100 by a coating method using a paint in which a material is dissolved. Moreover, when forming the resin layer 110 with a film, it can be produced on the substrate 100 by attaching the film to the substrate 100 with an adhesive or the like.

  The light reflecting layer 120 is a layer made of silver or a silver alloy. Since silver has a high reflectance in the visible light region among elements, it is preferable from the viewpoint of increasing the reflection efficiency of the light reflecting plate.

  Further, when the light taken into the daylighting apparatus 10 is reflected, silver does not attenuate the light in the wavelength range of 700 to 1000 nm out of the wavelength range of 400 to 1000 nm of the light taken into the daylighting apparatus 10. Can be reflected. In particular, in the wavelength range of 400 to 1000 nm, the photosynthesis effective wavelength range necessary for plant photosynthesis is 400 to 700 nm, while the light in the near infrared wavelength range of 700 to 1000 nm promotes photosynthesis. (Emerson effect). Therefore, in this embodiment, when the light reflecting layer 120 is a layer made of silver or a silver alloy, when the light taken into the daylighting apparatus 10 is reflected, the near infrared wavelength region is 700 to 1000 nm. Can be prevented from being attenuated. In the present embodiment, the sunlight taken in from the daylighting port 11 shown in FIG. 1 is guided into the daylighting apparatus 10 while being reflected by the light reflection layer 120, and the guided light is emitted from the light emission port 12. The ratio of the photon in the near-infrared region with a wavelength of 700 to 1000 nm in the light irradiated into the plant factory 1 from the light emission opening 12 when irradiated from the light source is preferably 40% or more, more preferably 50% or more. It can be done. As a result, the growth of the plant 30 in the daylighting device 20 installed in the plant factory 1 can be promoted. Note that the sunlight taken into the daylighting apparatus 10 normally contains near-infrared light having a wavelength of 700 to 1000 nm at a rate of 50 to 70%.

  On the other hand, when an artificial light source such as a fluorescent lamp is used as in a conventional closed plant factory, the wavelength of light emitted from the artificial light source such as a fluorescent lamp is usually in a photosynthesis effective wavelength region. Since it is -700 nm and does not contain light of 700-1000 nm which is a near infrared wavelength region, the growth of plants was insufficient. Further, if an artificial light source such as a fluorescent lamp includes light in the wavelength range of 700 to 1000 nm in addition to light in the wavelength range of 400 to 700 nm, or supplemented with an artificial light source, the cost will be greatly increased. There are also challenges.

  Furthermore, when the present inventors examined, the light reflection layer of the daylighting apparatus, conventionally used aluminum or aluminum alloy, although the reflection efficiency is relatively high, there is an absorption peak peculiar to aluminum in the vicinity of 800 nm, Therefore, when the light reflection layer of the daylighting device is formed of aluminum or an aluminum alloy, the light taken into the daylighting device is reflected by the light reflection layer, so that light in the wavelength region of 700 to 1000 nm is attenuated. It was recognized that And since the lighting device which forms a light reflection layer with aluminum or an aluminum alloy attenuates the light of a wavelength range of 700-1000 nm, when it is used for plant factories, the growth of plants is insufficient. There was a problem of becoming.

  On the other hand, according to the present invention, the light reflecting layer 120 constituting the lighting device 10 is formed of a layer made of silver or a silver alloy, so that the light taken from the lighting port 11 is reflected by the light reflecting layer 120. Even when it is made to grow, plant growth can be promoted by preventing light in the wavelength region of 700 to 1000 nm from being attenuated, thereby solving the above-mentioned conventional problems.

  Such a light reflection layer 120 can be formed by an electroless plating method in which silver is reduced and precipitated by a silver mirror reaction, for example, a spray plating method. In addition, it can be formed by an electroplating method in which electrolysis is performed in an aqueous solution containing silver ions, an evaporation method in which silver is evaporated in a reduced pressure atmosphere to form a film.

  The thickness of the light reflection layer 120 is preferably 0.01 to 0.3 μm, more preferably 0.08 to 0.15 μm. If the thickness of the light reflecting layer 120 is too thin, pinholes are generated and the reflectance may be reduced. On the other hand, if the thickness of the light reflection layer 120 is too thick, a desired glossy surface cannot be obtained, and the reflectance may be lowered. Also, from the economical viewpoint, it is not desirable that the thickness of the light reflecting layer 120 is too thick.

  Further, in the case where the light reflecting layer 120 is made of a silver alloy, an alloy mainly containing silver may be used, but the silver content in the silver alloy is preferably 97% by weight or more, and more Preferably it is 99 weight% or more.

  The protective layer 130 is a layer for protecting the light reflecting layer 120. Since the light reflecting layer 120 is made of silver or a silver alloy, the light reflecting layer 120 is likely to be discolored or contaminated when exposed to the atmosphere. In particular, the light reflecting layer 120 has a property of being easily discolored when the atmosphere contains a trace amount of a sulfur-based gas. . In addition, when cleaning dust and dirt adhering to the light reflecting layer 120, the light reflecting layer 120 also has a property of easily leaving a color change mark due to a detergent. Therefore, the protective layer 130 is a layer provided on the light reflecting layer 120 in order to prevent these, and by providing the protective layer 130, it is possible to maintain the performance and maintain the lighting device 10 over a long period of time.

  As the protective layer 130, a film made of an organic resin material, an inorganic material, or a mixture thereof is used. Or you may comprise in two layers of the film | membrane of an organic resin material, and the film | membrane of an inorganic material.

  The organic resin material may be any material that is transparent and can be thinned. For example, a polyester resin, an acrylic resin, a silicone resin, or the like can be used. Further, as the inorganic material, titanium oxide or the like excellent in contamination resistance can be used. When the protective layer 130 is formed of an organic resin material, for example, the protective layer 130 may be manufactured by a coating method using a coating solution in which an organic resin material is dissolved or a method in which an organic resin material is attached in a film shape. it can.

  In the present embodiment, the protective layer 130 may be an increased reflection film. The increased reflection film is formed by laminating a layer made of a material with a large refractive index such as titanium oxide and a layer made of a material with a small refractive index such as silicon oxide into two layers, and the optical thickness of each layer. The thickness (physical film thickness × refractive index) is λ / 4 (λ: wavelength of light), and the entire optical thickness is λ / 2. By using the protective layer 130 as an increased reflection film, the regular reflectance of light can be further improved.

  The thickness of the protective layer 130 is preferably 1 to 15 μm, more preferably 3 to 10 μm. If the thickness of the protective layer 130 is too thin, the protective effect of the light reflecting layer 120 is reduced, and the light reflecting layer 120 may be discolored or may be easily contaminated. On the other hand, if the thickness of the protective layer 130 is too thick, the reflectance may decrease.

  Next, a method for manufacturing a light reflecting plate constituting the daylighting apparatus 10 of the present embodiment will be described.

  First, a metal plate for constituting the base body 100 is prepared, and the resin layer 110 is formed on the surface of the metal plate. The resin layer 110 is formed by applying a coating method using a paint in which a material for forming the resin layer 110 is dissolved on the base 100 or a film made of the material for forming the resin layer 110 to the base 100 with an adhesive or the like. It can be formed by a method of attaching. Then, a light reflection layer 120 made of silver or a silver alloy is formed on the surface of the resin layer 110 formed on the substrate 100. Below, the method to form the light reflection layer 120 which consists of silver by the electroless-plating method is demonstrated.

  First, in order to further improve the adhesion between the resin layer 110 and the light reflecting layer 120, the surface of the light reflecting layer 120 is subjected to corona discharge treatment or glow discharge treatment.

  Next, an aqueous solution (pretreatment solution) containing stannic chloride, stannous chloride and ferric chloride containing hydrochloric acid is applied to the surface of the resin layer 110, so that tin as a catalyst is added to the resin layer 110. Form on the surface. In addition, it is preferable to use what adjusted pH to 2 or less as a pretreatment solution. Next, the surface of the resin layer 110 on which tin is formed is cleaned using ion-exchanged water or distilled water, and the pretreatment solution remaining on the surface of the resin layer 110 is removed.

  Next, a silver nitrate aqueous solution is applied to the surface of the resin layer 110. As a result, the silver deposited on the surface of the resin layer 110 replaces the tin formed using the pretreatment solution, and a silver starting nucleus is formed. Next, the surface of the resin layer 110 is washed with ion-exchanged water or distilled water, and the excess silver nitrate aqueous solution remaining on the surface of the resin layer 110 is removed.

  Next, an aqueous ammoniacal silver nitrate solution having a pH of 10 to 13 and a reducing agent aqueous solution having a pH of 8 to 12 containing a reducing agent (for example, hydrazinium sulfate, glyoxal, etc.) are sprayed on the surface of the resin layer 110 on which the silver starting nucleus is formed. Are injected at the same time. In this case, as the reducing agent aqueous solution, an aqueous solution obtained by dissolving or diluting the reducing agent in water and adding alkali to sodium hydroxide is used. Thus, the light reflecting layer 120 made of silver is formed using silver formed on the surface of the resin layer 110 as a starting nucleus.

  Next, cleaning is performed using ion-exchanged water or distilled water to remove the ammoniacal silver nitrate aqueous solution and the reducing agent aqueous solution remaining on the surface of the light reflecting layer 120, and the air is blown to adhere to the surface of the light reflecting layer 120. Blow off the water droplets, and then dry. Drying conditions can be 70 degreeC and 20 minutes, for example.

  In the present embodiment, when forming the light reflection layer 120, an immersion method may be used instead of the above-described spray injection method, and further, instead of the above-described electroless plating method, The light reflecting layer 120 may be formed by a conventionally known electroplating method or vapor deposition method.

  Next, the protective layer 130 is formed on the light reflecting layer 120. The protective layer 130 can be formed by applying a solution for a protective layer containing a resin that constitutes the protective layer 130 on the light reflecting layer 120 and drying it. The drying temperature is preferably 70 to 120 ° C, more preferably 80 to 100 ° C. The drying time is preferably 20 to 90 minutes, more preferably 30 to 60 minutes.

  As described above, the light reflecting plate constituting the daylighting apparatus 10 of the present embodiment is manufactured.

  And as above-mentioned, the lighting apparatus 10 of this embodiment is equipped with the light reflection layer 120 which consists of silver or a silver alloy on the inner surface, and the sunlight taken in from the lighting port 11 is at least once, Preferably, after being reflected by the light reflecting layer 120 made of silver or a silver alloy formed on the inner surface of the daylighting apparatus 10 twice or more, the plant factory 1 is irradiated from the light emission port 12. Here, the silver which comprises the light reflection layer 120 is not attenuate | damping the light of a 700-1000 nm wavelength range among the 400-1000 nm wavelength ranges of the sunlight taken in by the lighting apparatus 10, as mentioned above. Therefore, according to this embodiment, the proportion of the photon in the near infrared region having a wavelength of 700 to 1000 nm in the light irradiated from the light emission port 12 into the plant factory 1 is 40%. Above, preferably 50% or more. Therefore, according to the daylighting apparatus 10 of this embodiment, in the plant factory 1, the photosynthesis effective wavelength range necessary for the photosynthesis of plants is in the range of 700 to 1000 nm having an action of promoting photosynthesis in addition to light of 400 to 700 nm. The near-infrared light can be irradiated with a sufficient amount of light, whereby the plant 30 arranged in the plant factory 1 can be cultivated well and efficiently. Moreover, according to this embodiment, it becomes possible to reduce the cost required for growing plants in the plant factory 1 by using sunlight instead of an artificial light source such as a fluorescent lamp. The daylighting apparatus 10 of the present invention takes advantage of the above characteristics to grow various plants that can be grown in the plant factory 1, especially leaf plants (eg, lettuce, spring chrysanthemum, spinach, komatsuna, mizuna, etc.) Can be suitably used for the cultivation of leaf vegetables that are eaten.

  The embodiment described above is described for facilitating the understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

<Example 1>
In Example 1, the lighting device shown in FIGS. 3 (A) and 3 (B) was produced, a cultivation test was performed using the produced lighting device, and each evaluation described below was performed. In Example 1, a pH 10 ammoniacal silver nitrate aqueous solution and a pH 10 reducing agent (hydrazinium sulfate) aqueous solution were used on a substrate 100 in which a resin layer made of an acrylic urethane resin was formed on a galvanized steel sheet. A daylighting apparatus was manufactured using a light reflection plate formed by forming a light reflection layer 120 made of silver having a thickness of 100 nm and a protective layer 130 made of acrylic silicon resin by an electroless plating method. In FIGS. 3A and 3B, L1 = 4230 mm, L2 = 770 mm, L3 = 1572 mm, W1 = W2 = W3 = W4 = 500 mm, α = 45 °, and β = 22 °.

  In addition, the daylighting unit for taking in sunlight is provided with a daylighting port made of transparent glass and a reflector for reflecting the light taken from the daylighting port into the daylighting device so that the light taken in from the daylighting port is released. By irradiating the cultivation zone provided with an area of 500 mm x 500 mm from the light opening, and planting twelve Chima Sanchu seedlings that have developed five leaves after 14 days from the sowing date. A cultivation test was conducted. In the cultivation test, the cultivation area was shielded from light other than the light from the daylighting device.

Then, the amount of light from the start of cultivation is measured using a spectroradiometer (Handy Lambda II, manufactured by Spectra Corp.) for 10 minutes as the photosynthetic quantum flux density (PPFD, mol / m ² · s) of the light irradiated to the cultivation area. Measure at intervals, calculate the integrated amount of photosynthetic quantum bundle density (integrated light amount of light that contributed to photosynthesis, PPFD × 600s), and continue the cultivation test until the integrated amount of photosynthetic quantum bundle density reaches 120 to 130 mol / m ² The following evaluation was performed.

Using a 700-1000 nm light intensity ratio spectroradiometer (Handy Lambda II, manufactured by Spectra Corp.), the 400-1000 nm spectrum of the light irradiated to the cultivation area is measured, and the cultivation area is irradiated. The intensity ratio of 700-1000 nm photons in the light was calculated. The results are shown in Table 1.

Fresh weight of leaves The weight of leaves cultivated was measured, and the fresh weight of leaves per strain was calculated. In addition, the measurement of the weight of a leaf was performed about all the 12 stocks, and what averaged the obtained result was made into the raw weight of the leaf per strain. The results are shown in Table 1.

The area of the leaf of the cultivated strain was measured, and the area of the leaf per sheet was calculated. In addition, the measurement of the area of a leaf was performed about all the 12 stocks, and what averaged the obtained result was made into the area of the leaf per sheet. The results are shown in Table 1.

<Comparative Example 1>
In Comparative Example 1, a lighting device shown in FIGS. 3A and 3B was manufactured in the same manner as in Example 1 except that the light reflecting layer was formed of aluminum, and the same as in Example 1. A cultivation test was conducted and evaluated in the same manner. The results are shown in Table 1.

<Comparative example 2>
In Comparative Example 2, a fluorescent lamp (3-wavelength white fluorescent lamp, 20W × 4) is used as a light source instead of the daylighting apparatus shown in FIGS. 3 (A) and 3 (B). A cultivation test was conducted in the same manner, and the same evaluation was performed. The results are shown in Table 1.

  As shown in Table 1, in Example 1 in which the light reflection layer made of silver was provided on the inner surface of the daylighting apparatus, the proportion of photons with a wavelength of 700 to 1000 nm in the light irradiated to the cultivation area was as high as 60%, As a result, the weight and leaf area of the cultivated strain increased. In addition, since it is an effect by silver that the ratio of the photon of wavelength 700-1000 nm in the light irradiated to a cultivation zone can be made high in this way, the light reflection layer was made into the silver alloy which has silver as a main component. Even in this case, it is considered that the same effect can be obtained.

On the other hand, in the comparative example 1 which provided the light reflection layer which consists of aluminum in the lighting device inner surface, the ratio of the photon with a wavelength of 700-1000 nm in the light irradiated to a cultivation area is as low as 10%, Therefore, it was cultivated The result was a decrease in the leaf weight and leaf area of the strain.
Similarly, in Comparative Example 2 using a fluorescent lamp as the light source, the ratio of the photons with a wavelength of 700 to 1000 nm in the light irradiated to the cultivation area is 0%. Therefore, the weight of the leaf of the cultivated strain and The result was a smaller leaf area.

DESCRIPTION OF SYMBOLS 1 ... Plant factory 10 ... Daylighting device 11 ... Daylighting port 12 ... Light emission port 100 ... Base | substrate 120 ... Light-diffusion layer 130 ... Protective layer

Claims (4)

A daylighting device for a plant factory having a daylighting part for taking in natural light and a light emitting part for irradiating the light taken from the daylighting part into the plant factory,
A vertical light guide unit that is formed by being surrounded by a light reflection plate having a light reflection layer made of silver or a silver alloy as an inner surface, and that extends in a vertical direction from the daylighting unit, thereby guiding light taken from the daylighting unit. When,
A light reflecting layer made of silver or a silver alloy is formed surrounded by the light reflecting plate having an inner surface, said at Rukoto connected to the lower end of the vertical light guide portion, the light from the vertical light guide portion light radiation portion anda bent portion leading to,
Light incorporated taken before Symbol lighting unit, after being reflected at least once by the light reflecting layer is irradiated from the light radiation portion in the plant factory, and is irradiated into the plant factory from the light radiation portion A daylighting apparatus for a plant factory, wherein the proportion of photons in the near infrared region having a wavelength of 700 to 1000 nm in light is 60% or more. The bent portion is
A first bent portion having one end connected to the lower end of the vertical light guide;
A horizontal light guide portion having one end connected to the other end of the first bent portion and extending in the horizontal direction;
A second bent portion having one end connected to the other end of the horizontal light guide;
2. The plant factory according to claim 1, further comprising: a second vertical light guide portion connected to the other end of the second bent portion and extending in a vertical direction toward the light emitting portion. Daylighting equipment.   The daylighting apparatus for a plant factory according to claim 1 or 2, wherein the light emission part is provided with a diffusion plate for diffusing the light taken from the daylighting part. A method of growing plants in a plant factory using a daylighting device capable of taking natural light and irradiating the taken light into the plant factory,
The lighting device is:
A vertical light guide unit that is formed by being surrounded by a light reflection plate having a light reflection layer made of silver or a silver alloy as an inner surface, and that extends in a vertical direction from the daylighting unit, thereby guiding light taken from the daylighting unit. When,
A light reflecting layer made of silver or a silver alloy is formed surrounded by the light reflecting plate having an inner surface, said at Rukoto connected to the lower end of the vertical light guide portion, the light from the vertical light guide portion light radiation portion have a, a bent portion leading to,
The natural light having a near-infrared photon ratio of a wavelength of 700 to 1000 nm is 60% or more in the plant factory after the light taken into the daylighting device is reflected at least once by the light reflection layer. A method for growing a plant characterized by irradiating with water.

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