Plant growing device and plant growing method

Abstract

To provide a plant growing device that can set periods when artificial light is emitted to plants and periods when it is not.SOLUTION: A plant growing device includes: at least one housing formed from a light-transmitting material and defining a closed growing space in which the above-ground portion of at least one plant is grown; at least one artificial light source arranged near the housing and emitting artificial light for growing the plant; and a movement control device that moves the artificial light source relative to the housing so as to create a period during which the plant in the growing space is irradiated with the artificial light output from the artificial light source and a period during which the plant in the growing space is not irradiated with the artificial light output from the artificial light source.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a plant growing device and a plant growing method for growing plants using artificial light. [Background technology]

[0002] Plant factories are being considered as a way to increase agricultural production and achieve stable harvests. In plant factories, it is possible to control various parameters, such as the intensity of light for photosynthesis irradiated on crops from artificial light sources, environmental conditions such as temperature, humidity, carbon dioxide (CO2) concentration, and wind speed in the plant growth space, and fertilizer components for plant growth. This makes it possible to produce crops year-round, dramatically increasing crop productivity.

[0003] Patent Document 1 discloses a plant growing device that includes a light source that emits light downward and a light-transmitting heat-insulating section that separates the space on the light source side from the space on the aboveground side. The heat-insulating section prevents the heat emitted by the light source from reaching the plants directly. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2017 / 047024 Summary of the Invention [Problem to be solved by the invention]

[0005] While plants grow during the day through photosynthesis, they also grow at night. Continuous illumination of light can reduce photosynthetic function and inhibit growth. Furthermore, continuous illumination of light can prevent some plants from flowering. In a plant growing device, it is preferable to provide periods of illumination to promote photosynthesis, and periods of no illumination to guide plant growth appropriately.

[0006] Therefore, the present invention provides a plant growing device and a plant growing method that can separate periods during which artificial light is irradiated onto plants and periods during which artificial light is not irradiated onto plants. [Means for solving the problem]

[0007] One aspect of the present invention provides a plant-growing device for growing plants, the plant-growing device comprising at least one housing formed of a light-transmitting material and defining a closed growing space in which an above-ground portion of at least one plant is grown, at least one artificial light source disposed near the housing and emitting artificial light for growing the plant, and a movement control device for moving the artificial light source relative to the housing so as to create a period during which the plant in the growing space is irradiated with the artificial light output from the artificial light source and a period during which the plant in the growing space is not irradiated with the artificial light output from the artificial light source.

[0008] Another aspect of the present invention provides a plant cultivation method, which comprises: relatively moving at least one housing made of a light-transmitting material and defining an enclosed cultivation space in which at least one above-ground part of a plant is cultivated, and at least one artificial light source emitting artificial light for growing the plant, to create a period during which the plant in the cultivation space is irradiated with the artificial light output from the artificial light source; and relatively moving the housing and the artificial light source, to create a period during which the plant in the cultivation space is not irradiated with the artificial light output from the artificial light source. Effect of the Invention

[0009] According to an aspect of the present invention, a plant cultivation space is defined by a housing. An artificial light source is disposed outside the cultivation space, and the cultivation space is thermally isolated from the artificial light source by the housing, and is less susceptible to the heat. In other words, the housing prevents the cultivation space from overheating. Therefore, the energy required to control the air temperature in the plant cultivation space can be reduced, and the cultivation space can be easily controlled to an environment suitable for the plant to be cultivated. Then, the movement control device moves the artificial light source relative to the housing, thereby creating a period during which the plant in the cultivation space is irradiated with artificial light (a period corresponding to daytime) and a period during which the plant is not irradiated (a period corresponding to nighttime). [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a front cross-sectional view showing a schematic configuration example of a plant growing device according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a front view of a light source panel of the plant growing device of FIG. [Diagram 3] 3 is a vertical cross-sectional view of the light source panel of FIG. 2. [Figure 4] FIG. 11 is a vertical cross-sectional view of a light source panel according to a modified example. [Diagram 5] FIG. 2 is a plan cross-sectional view of the plant cultivation device of FIG. 1. [Figure 6] 6 is a plan cross-sectional view of the plant growing device of FIG. 5 in which a pair of light source panels have been moved. [Figure 7] FIG. 13 is a plan cross-sectional view of a modified plant growing device in which a plurality of growing spaces are moved. [Figure 8] FIG. 4 is a plan cross-sectional view of a plant growing device according to a modified example of the first embodiment. [Figure 9] FIG. 9 is a plan cross-sectional view of the plant growing device of FIG. 8 in which the pair of light source panels have been moved. [Figure 10] FIG. 11 is a plan cross-sectional view of a plant growing device according to another modified example of the first embodiment. [Figure 11] FIG. 11 is a plan cross-sectional view of a plant growing device according to still another modified example of the first embodiment. [Figure 12] FIG. 12 is a plan cross-sectional view of the plant growing device of FIG. 11 in which a pair of light source panels have been moved. [Figure 13] FIG. 12 is a plan cross-sectional view of the plant growing device of FIG. 11 in which two pairs of light source panels have been moved. [Figure 14] FIG. 11 is a plan cross-sectional view of a plant growing device according to still another modified example of the first embodiment. [Figure 15] FIG. 15 is a plan cross-sectional view of the plant growing device of FIG. 14 in which a pair of light source panels have been moved. [Figure 16] FIG. 15 is a plan cross-sectional view of the plant growing device of FIG. 14 in which two pairs of light source panels have been moved. [Figure 17] FIG. 6 is a front cross-sectional view showing a schematic configuration example of a plant growing device according to a second embodiment of the present invention. [Figure 18] FIG. 18 is a side cross-sectional view of the plant growing device of FIG. 17. [Figure 19] FIG. 11 is a plan view of a plant growing device according to a third embodiment of the present invention. [Figure 20] FIG. 20 is a front cross-sectional view of the plant growing device of FIG. 19. [Figure 21] FIG. 20 is an exploded cross-sectional view of the plant growing device of FIG. 19. [Figure 22] FIG. 20 is a cross-sectional front view of the plant growing device of FIG. 19 immediately after assembly. [Diagram 23] FIG. 20 is a front cross-sectional view of the plant growing device of FIG. 19 disassembled for removal of a mature plant. [Figure 24] FIG. 20 is a front cross-sectional view showing the air flow in the plant growing device of FIG. 19. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Various embodiments of the present invention will now be described with reference to the accompanying drawings, in which the drawings are not necessarily drawn to scale and some features may be exaggerated or omitted.

[0012] As shown in Fig. 1, a plant growing device 1 according to a first embodiment has a cultivation device 2 for growing a large number of plants. The plant growing device 1 is arranged in a plant factory. The plant 3 grown in the plant growing device 1 is, for example, an agricultural crop such as beans, but may be other plants that perform photosynthesis. The plant growing device 1 according to the first embodiment is preferably used for plants that grow long trunks and have many leaves that overlap vertically. A large number of plants 3 are arranged in a row in a direction perpendicular to the plane of the paper in FIG. 1 (see FIGS. 5 and 6).

[0013] The cultivation device 2 has an upper part 2A and a lower part 2B arranged below the upper part 2A. A plurality of liquid fertilizer tanks 4A, 4B are arranged in the lower portion 2B. The plurality of liquid fertilizer tanks 4A, 4B are arranged in a direction perpendicular to the plane of FIG. 1 (see FIG. 5 and FIG. 6). The roots (including the main root and lateral roots) of the plant 3 are placed inside each of the liquid fertilizer tanks 4A and 4B, and the roots grow here. The liquid fertilizer tanks 4A and 4B are containers that hold a nutrient solution 41 (also called liquid fertilizer or liquid fertilizer) that contains fertilizer to be given to the roots of the plant 3.

[0014] A plant support panel 5 is attached to the upper part of each of the liquid fertilizer tanks 4A and 4B. The trunks of a plurality of plants 3 pass through the plant support panel 5, and the plant support panel 5 supports these plants 3. The plant support panel 5 may be breathable. For example, the plant support panel 5 may be porous, or the plant support panel 5 may have a large number of through-holes.

[0015] The plant growing device 1 further has a nutrient solution supplying system 10. The nutrient solution supplying system 10 is connected to the liquid fertilizer tanks 4A, 4B via a liquid fertilizer pipeline 11, and supplies liquid fertilizer 41 to the liquid fertilizer tanks 4A, 4B.

[0016] The cultivation apparatus 2 further includes a housing 6. The housing 6 extends vertically from the lower portion 2B to the upper portion 2A of the cultivation apparatus 2. In this embodiment, a plurality of housings 6 are provided, and the plurality of housings 6 are arranged in a direction perpendicular to the paper surface of FIG. 1 (see FIG. 5 and FIG. 6). A lower space 2D in which a liquid fertilizer tank 4A or 4B is disposed is provided in the lower part of each housing 6. The liquid fertilizer tanks 4A and 4B are disposed inside these housings 6, respectively.

[0017] Two cultivation spaces 8A and 8B are arranged in the upper portion 2A of the cultivation device 2. The cultivation spaces 8A and 8B are spaces above the liquid fertilizer tanks 4A and 4B, respectively, and are spaces inside the housing 6. The cultivation spaces 8A and 8B are arranged close to each other in the direction perpendicular to the plane of FIG. 1 (see FIGS. 5 and 6). In this embodiment, in each of the cultivation spaces 8A and 8B, the above-ground parts (i.e., stems and leaves) of multiple plants 3 grow (are cultivated). However, the above-ground part of only one plant 3 may grow in each of the cultivation spaces 8A and 8B. Each housing 6 defines an enclosed growing space 8A or 8B.

[0018] Further, a pair of light source panels (artificial light source) 7 are disposed on the upper portion 2A of the cultivation device 2. The growth spaces 8A and 8B are interposed between these light source panels 7. In other words, each light source panel 7 is disposed near the growth spaces 8A and 8B. The pair of light source panels 7 are oriented vertically, arranged parallel to each other, and facing each other.

[0019] Each light source panel 7 emits artificial light L for growing the plants 3. The light source panels 7 are arranged on both sides of the growth spaces 8A, 8B, and supply artificial light L from the sides to the plants 3 in the growth spaces 8A, 8B. Therefore, the artificial light L can be applied as evenly as possible to both the upper and lower leaves of the plant 3 in the growth stage where the stem is long and has many leaves overlapping vertically.

[0020] In this embodiment, a pair of light source panels 7 are arranged on both sides of the growing spaces 8A, 8B, but one light source panel 7 may be arranged on one side of the growing spaces 8A, 8B. A pair of light source panels 7 are used in common for the multiple cultivation spaces 8A, 8B to supply artificial light L to the cultivation spaces 8A, 8B. However, the cultivation spaces 8A, 8B use these light source panels 7 in a time-division manner (i.e., during different periods).

[0021] The housing 6 that defines the cultivation spaces 8A and 8B is made of a light-transmitting material, such as glass or a transparent resin. Examples of the transparent resin that can be used include, but are not limited to, acrylic, polyethylene terephthalate, polycarbonate, and polyvinyl chloride. Each housing 6 has a wall 6a interposed between the cultivation space 8A or 8B and the light source panel 7. The wall 6a is formed flat, and the walls 6a of the pair of housings 6 are disposed parallel to each other. Each housing 6 suppresses or inhibits heat radiation and heat conduction from light source panel 7, which is a heat source, and prevents overheating of cultivation spaces 8A, 8B. In this embodiment, each housing 6 surrounds the entire growing space 8A or 8B. However, each housing 6 does not necessarily have to surround the entire growing space 8A or 8B. For example, the upper and lower walls of each housing 6 may be omitted, or the upper and lower walls may not be transparent. The portion of each housing 6 that is present in the lower part 2B and surrounds the liquid fertilizer tank 4A or 4B may not be transparent.

[0022] In order to prevent each light source panel 7 from overheating, a blower (not shown) may be used to generate airflow around each light source panel 7, thereby cooling each light source panel 7 with air. Instead of or in addition to the blower, a refrigerant pipe or refrigerant chamber (not shown) for lowering the temperature of each light source panel 7 may be arranged near each light source panel 7 (for example, so as to be in contact with each light source panel 7). The refrigerant may be, for example, a gas such as air or hydrofluorocarbon, or a liquid such as water or ammonia. The refrigerant pipe or refrigerant chamber is preferably provided on the side opposite to the light-emitting surface of each light source panel 7. A fin (not shown) for improving cooling efficiency may be provided on the wall opposite to the light emitting surface of each light source panel 7.

[0023] The distance between a pair of walls 6a of the housing 6 in FIG. 1 is set to a size that allows artificial light L to be applied substantially evenly and sufficiently to each leaf of the plant 3 that has grown to a certain extent. However, it is preferable that the interval between the walls 6a is set so as to restrict excessive lateral growth of the plant 3. In other words, it is preferable that the position of the wall 6a with respect to the plant 3 is determined so as to restrict lateral growth of the leaves of the plant 3 cultivated inside the cultivation spaces 8A, 8B. Specifically, it is preferable that the horizontal distance from the base of the plant 3 to the wall 6a is set smaller than the maximum horizontal distance from the base of the plant 3 that is predicted to be reached by the tip of a leaf that has grown to its maximum extent, assuming that the housing 6 does not exist. In this case, since the wall 6a restricts excessive growth of the leaves of the plant 3, the plant 3 can be cultivated in a small space (small width).

[0024] The plant growing device 1 further includes an air conditioning system 12 , a light emission control device 18 , an environmental control device 20 and a movement control device 30 . The air conditioning system 12 adjusts the environment of the cultivation apparatus 2 in which the plants are grown to temperature, humidity, and carbon dioxide (CO2) concentration suitable for growing the plants. The air conditioning system 12 is connected to the housing 6 via an air pipe 14 and communicates with the lower space 2D inside the housing 6. The air conditioning system 12 is also connected to the housing 6 via an air pipe 16 and communicates with the growth spaces 8A and 8B inside the housing 6. The air conditioning system 12 supplies conditioned air to the cultivation apparatus 2 through the air pipe 14 or 16, and takes in air inside the cultivation apparatus 2 through the air pipe 16 or 14. In the lower part 2B of the cultivation apparatus 2, there are a plurality of ventilation gaps 40 between the housing 6 and the liquid fertilizer tank 4A or 4B, and the air conditioned by the air conditioning system 12 can flow through the ventilation gaps 40 from the upper part 2A (growth spaces 8A, 8B) of the cultivation apparatus 2 to the lower part 2B (lower space 2D) or from the lower part 2B to the upper part 2A.

[0025] The light emission control device 18 controls the light emission of the light source panel 7. For example, the light emission control device 18 turns the light source panel 7 on and off. The environmental control device 20 is a computer processor. The environmental control device 20 controls the environment inside the cultivation apparatus 2. As described below, the environmental control device 20 issues commands to the nutrient solution supply system 10 and the air conditioning system 12, and alternately controls the cultivation spaces 8A, 8B to an environment that promotes photosynthesis of plants and an environment that suppresses photosynthesis. The movement controller 30 is also a computer processor. The movement controller 30 may be a separate processor from the environmental controller 20 or may be the same processor as the environmental controller 20. The movement control device 30 controls a movement mechanism (not shown) to move the light source panel 7 relative to the housing 6 (i.e., to move the light source panel 7 relative to the cultivation spaces 8A, 8B) as described below. The cultivation device 2 has a movement mechanism that moves the light source panel 7 relative to the cultivation spaces 8A, 8B. The movement mechanism may be, for example, wheels driven by a motor, a belt conveyor mechanism, a caterpillar mechanism, or a rack and pinion mechanism.

[0026] As shown in FIG. 2, the light source panel 7 has a height X that is greater than the upper limit of the growth height of the plants 3, and a width Y that allows artificial light L to be applied almost evenly and sufficiently to multiple plants 3 planted at intervals from each other. The light source of the light source panel 7 may be, for example, a plurality of OLED (organic light-emitting diode) elements, but in this embodiment, a plurality of LED (light-emitting diode) chips that generate less heat are used. As shown in Figures 2 and 3, the light source panel 7 has a flat substrate 32 serving as a support, and a number of LED chips 33 arranged on the substrate 32. These LED chips 33 are of the same type and emit white visible light. Therefore, when the same current and voltage are applied, these LED chips 33 emit artificial light L with the same photon flux density. The LED chips 33 are regularly arranged (specifically, in a matrix) at equal intervals vertically and horizontally. However, LED chips 33 that emit red wavelength light more strongly than other wavelengths and LED chips 33 that emit blue wavelength light more strongly than other wavelengths may be arranged on the substrate 32. In addition, LED chips 33 that emit green wavelength light more strongly than other wavelengths may be arranged on the substrate 32. The LED chip 33 is mounted in a light emitting area of ​​the light source panel 7, the area having a height X1 and a width Y1.

[0027] The substrate 32 is provided with wiring (not shown) for lighting these LED chips 33. A light emission control device 18 (see FIG. 1) for controlling the light emission of these LED chips 33 is provided outside the light source panel 7, and the wiring is electrically connected to the light emission control device 18. In order to increase the efficiency of use of the artificial light L in the cultivation spaces 8A and 8B, it is preferable that the surface of the substrate 32 on the side of the LED chip 33 has a high light reflectance. The substrate 32 is preferably made of a light-reflecting material (e.g., a metal with a smooth surface). The surface of the substrate 32 on the side of the LED chip 33 may be coated with a light-reflecting paint. 2 and 3 are merely examples. The size, number and spacing of the LED chips 33 are not limited to those shown in the figures. In this embodiment, the substrate 32 of the light source panel 7 is a flat plate, but as shown in Fig. 4, the substrate 32 may be a corrugated plate. Fig. 4 is a vertical cross-sectional view of the light source panel 7 as seen in the same manner as in Fig. 3.

[0028] In this embodiment, a light source panel 7 having a plurality of LED chips 33 that generate little heat is used as the artificial light source. However, the artificial light source may also be at least one fluorescent lamp, at least one cold cathode fluorescent tube, or other light sources.

[0029] As shown in the planar cross-sectional views of Figures 5 and 6, the liquid fertilizer tanks 4A and 4B are long containers, and multiple plants 3 are lined up along the longitudinal direction of each liquid fertilizer tank. The light source panel 7 and the cultivation spaces 8A and 8B extend along the longitudinal direction of the liquid fertilizer tanks 4A and 4B. In this embodiment, as shown in Fig. 5 and Fig. 6, each light source panel 7 is realized in a state facing the growing space 8A and a state facing the growing space 8B. In this manner, the stroke of the light source panel 7 during movement is set so that the light source panel 7 can face a plurality of growing spaces 8A.

[0030] A light-shielding wall 50 is interposed between the housings 6 surrounding the cultivation spaces 8A and 8B. In order to increase the efficiency of using the artificial light L in the cultivation spaces 8A and 8B, it is preferable that both sides of the light-shielding wall 50 have a high light reflectance. It is preferable that the light-shielding wall 50 is formed from a material that reflects light (for example, a metal having smooth surfaces). Both sides of the light-shielding wall 50 may be coated with a light-reflecting paint.

[0031] In this embodiment, the housing 6, the fertilizer tanks 4A, 4B, and the growing spaces 8A, 8B are fixed. The growing spaces 8A, 8B above the liquid fertilizer tank 4 are stationary (ie, fixed) in fixed positions. As described above, the movement control device 30 controls a movement mechanism (not shown) so as to move the light source panel 7 relatively to the housing 6 and therefore to the cultivation spaces 8A and 8B. The movement control device 30 reciprocates each light source panel 7 along the longitudinal direction of the housing 6 (the longitudinal direction of the growth spaces 8A, 8B). In other words, the movement control device 30 moves the light source panels 7 while keeping the growth spaces 8A, 8B stationary. The movement control device 30 moves the pair of light source panels 7 synchronously.

[0032] FIG. 5 shows a state where a pair of light source panels 7 are positioned on the cultivation space 8A side and irradiate artificial light to the plant 3 in the cultivation space 8A. In this state, artificial light is not irradiated to the plant 3 in the cultivation space 8B. In other words, the cultivation space 8A is in a daytime state, and the cultivation space 8B is in a nighttime state. The light-shielding wall 50 prevents the artificial light from traveling from the cultivation space 8A to the cultivation space 8B. Therefore, a state where the plant in the cultivation space 8A is irradiated with the artificial light output from the light source panel 7 and a state where the plant in the cultivation space 8B is not irradiated with the artificial light output from the light source panel 7 are simultaneously created. On the other hand, FIG. 6 shows a state where a pair of light source panels 7 are positioned on the cultivation space 8B side and irradiate artificial light to the plant 3 in the cultivation space 8B. In this state, artificial light is not irradiated to the plant 3 in the cultivation space 8A. In other words, the cultivation space 8B is in a daytime state, and the cultivation space 8A is in a nighttime state. The light-shielding wall 50 prevents the artificial light from traveling from the cultivation space 8B to the cultivation space 8A. Therefore, a state where the plant in the cultivation space 8B is irradiated with the artificial light output from the light source panel 7 and a state where the plant in the cultivation space 8A is not irradiated with the artificial light output from the light source panel 7 are simultaneously created.

[0033] The movement control device 30 may move the light source panel 7 from the vicinity of one of the cultivation spaces 8A, 8B to the vicinity of the other in a 12-hour cycle, for example. In this case, in each of the cultivation spaces 8A, 8B, 12 hours of the day are daytime and the other 12 hours are nighttime. However, the movement control device 30 may move the light source panel 7 from one of the growing spaces 8A, 8B to the other in other cycles. For example, the light source panel 7 may be moved from one of the growing spaces 8A, 8B to the other in a 6-hour cycle, a 4-hour cycle, or a 3-hour cycle. In any case, in each of the growing spaces 8A, 8B, a total of 12 hours are daytime and a total of 12 hours are nighttime. In this way, by the movement control device 30 moving the light source panel 7 relative to the housing 6, it is possible to alternately create periods in which the plants in the cultivation space 8A are irradiated with artificial light (periods corresponding to daytime) and periods in which they are not irradiated (periods corresponding to nighttime). Also, it is possible to alternately create periods in which the plants in the cultivation space 8B are irradiated with artificial light (periods corresponding to daytime) and periods in which they are not irradiated (periods corresponding to nighttime).

[0034] According to this embodiment, the housing 6 thermally separates the growing spaces 8A, 8B from the light source panel 7, and the growing spaces 8A, 8B are less susceptible to the effects of heat. In other words, the housing 6 prevents the growing spaces 8A, 8B from overheating. This allows the air conditioning system 12 to reduce the energy required to control the air temperature in the plant growing spaces 8A, 8B, and makes it easy to control the growing spaces 8A, 8B to an environment suitable for the plants to be cultivated.

[0035] Moreover, by moving the light source panel 7 relative to the cultivation spaces 8A, 8B with the movement control device 30, it is possible to simultaneously create a state in which plants in one of the cultivation spaces 8A, 8B are irradiated with artificial light (a state corresponding to daytime) and a state in which plants in the other of the cultivation spaces 8A, 8B are not irradiated (a state corresponding to nighttime). Furthermore, the movement control device 30 moves the light source panel 7 relatively to the plurality of cultivation spaces 8a, 8b so that the artificial light output from the light source panel 7 is supplied to the different cultivation spaces 8a, 8b for different periods. Therefore, it is possible to change the cultivation spaces irradiated with artificial light and the cultivation spaces not irradiated with artificial light. In other words, by multiple cultivation spaces 8A, 8B sharing the light source panel 7 and using the light source panel 7 in a time-division manner (i.e., at different periods), it is possible to simultaneously place one of the cultivation spaces 8A, 8B in an environment irradiated with artificial light and the other cultivation space 8A, 8B in an environment that is not irradiated with artificial light, and by switching between the cultivation spaces that are irradiated with artificial light and the cultivation spaces that are not, it is possible to alternate between periods when the plants in each cultivation space are irradiated with artificial light and periods when they are not. Since the multiple growing spaces 8A, 8B share the light source panel 7, the number of light source panels 7 does not need to correspond to the number of growing spaces 8A, 8B. In this embodiment, the light source panels 7 are arranged on both sides of the two growing spaces 8A, 8B, so that there is no need to provide two light source panels 7 corresponding to the two growing spaces 8A, 8B. Therefore, an increase in the number of light source panels 7 can be prevented.

[0036] In addition, since the multiple cultivation spaces 8A, 8B use the light source panel 7 in a time-division manner, the light source panel 7 can be driven continuously. This reduces the number of times the light source panel 7 is switched on and off, thereby shortening the period during which the light source panel 7 is not in use. In addition, when the artificial light source is a fluorescent lamp or a cold cathode fluorescent tube, it is possible to reduce failures caused by switching on and off, and save power consumption. However, the light source panel 7 does not need to be driven permanently. Many types of plants flower when they sense changes in day length. Therefore, even if the light source panel 7 is moved from the vicinity of one of the cultivation spaces 8A and 8B to the vicinity of the other in a 12-hour cycle, for example, an off time during which the light source panel 7 does not emit light may be provided to bring about a change in day length.

[0037] The movement control device 30 moves the light source panel 7 along the longitudinal direction of the growth spaces 8A, 8B relative to the fixed growth spaces 8A, 8B. However, as in a modified example shown in FIG. 7, the movement control device 30 may move the housing 6 surrounding the liquid fertilizer tanks 4A, 4B together with the cultivation spaces 8A, 8B along the longitudinal direction of the cultivation spaces 8A, 8B without moving the light source panel 7. In this modified example, the state of FIG. 5 in which the light source panel 7 is located on the cultivation space 8A side can be transitioned to the state of FIG. 7 in which the light source panel 7 is located on the cultivation space 8B side and artificial light is irradiated to the plant 3 in the cultivation space 8B. The state of FIG. 7 is equivalent to the state of FIG. 6, in which the cultivation space 8B is in a daytime state and the cultivation space 8A is in a nighttime state. In this modified example, it is preferable that the liquid fertilizer pipe 11 and the air pipes 14, 16 are extendable and bendable. In any case, the movement control device 30 moves the light source panel 7 relative to the housing 6.

[0038] In this embodiment, one housing 6 encloses the liquid fertilizer tank 4A and the growing space 8A, and the other housing 6 encloses the liquid fertilizer tank 4B and the growing space 8B. The environments within these housings 6 are isolated from each other and can be considered as independent cultivation units. Therefore, the environmental control device 20 (see FIG. 1) can easily place the combination of the growing space 6A and the liquid fertilizer tank 4A and the combination of the growing space 6B and the liquid fertilizer tank 4B in different environments.

[0039] The environmental control device 20 controls the cultivation space 8A or 8B to which the light source panel 7 irradiates visible light to an environment that promotes photosynthesis of the plant 3, and controls the cultivation space 8A or 8B to which the light source panel 7 does not irradiate visible light to an environment that suppresses photosynthesis of the plant 3. That is, during a period in which artificial light is supplied from the light source panel 7 to the cultivation space 8A shown in FIG. 5 and artificial light is not supplied to the cultivation space 8B, the combination of the cultivation space 8A and the liquid fertilizer tank 4A is controlled to an environment that promotes photosynthesis of the plant 3, and the combination of the cultivation space 8B and the liquid fertilizer tank 4B is controlled to an environment that suppresses photosynthesis of the plant 3. Conversely, during a period in which artificial light is supplied from the light source panel 7 to the cultivation space 8B shown in FIG. 6 or FIG. 7 and artificial light is not supplied to the cultivation space 8A, the combination of the cultivation space 8B and the liquid fertilizer tank 4B is controlled to an environment that promotes photosynthesis of the plant 3, and the combination of the cultivation space 8A and the liquid fertilizer tank 4A is controlled to an environment that suppresses photosynthesis of the plant 3. In other words, photosynthesis is promoted in the cultivation space 8A or 8B corresponding to the daytime and the liquid fertilizer tank 4A or 4B corresponding to that cultivation space, and photosynthesis is suppressed in the cultivation space 8A or 8B corresponding to the nighttime and the liquid fertilizer tank 4A or 4B corresponding to that cultivation space.

[0040] Specifically, the environmental control device 20 executes at least one of the following environmental control examples. In one example of environmental control, the environmental control device 20 controls the air conditioning system 12 to raise the temperature of the cultivation space 8A or 8B corresponding to the daytime and the liquid fertilizer tank 4A or 4B corresponding to the cultivation space, and to lower the temperature of the cultivation space 8A or 8B corresponding to the nighttime and the liquid fertilizer tank 4A or 4B corresponding to the cultivation space. This reduces the operating cost of the cultivation unit corresponding to the nighttime. Also, it suppresses the metabolism of the plant 3 in the cultivation unit corresponding to the nighttime. In another example of the environmental control, the environmental control device 20 controls the air conditioning system 12 to increase the concentration of CO2 in the air of the cultivation space 8A or 8B corresponding to the daytime and to decrease the concentration of CO2 in the air of the cultivation space 8A or 8B corresponding to the nighttime. Therefore, the operating cost of the cultivation unit corresponding to the nighttime can be reduced.

[0041] In another example of environmental control, the environmental control device 20 may control the air conditioning system 12 to appropriately control the humidity in the cultivation space 8A or 8B corresponding to the daytime, eliminating the need to control the humidity in the cultivation space 8A or 8B corresponding to the nighttime. When humidity is high, a lot of water vapor passes through the stomata of plant leaves, making it difficult for plants to absorb CO2 and suppressing photosynthesis. In particular, when water droplets are on the leaves, the stomata are closed and plants cannot absorb CO2. Also, when humidity is high, transpiration from the stomata of the leaves becomes inactive, inhibiting plant growth. On the other hand, if humidity is too low, plants' photosynthetic ability decreases due to dry stress, so there is an optimum range for daytime humidity. When the external environment of the cultivation apparatus 2 is highly humid, humidity control only needs to be performed in the cultivation units corresponding to the daytime, so that the operating costs of the cultivation units corresponding to the nighttime can be reduced.

[0042] In another example of environmental control, the environmental control device 20 controls the nutrient solution supply system 10 to increase the amount of top dressing (specifically, the concentration of fertilizer) supplied to the liquid fertilizer tank 4A or 4B corresponding to the cultivation space 8A or 8B corresponding to the daytime, and to decrease the amount of top dressing supplied to the liquid fertilizer tank 4A or 4B corresponding to the cultivation space 8A or 8B corresponding to the nighttime. This reduces the operating cost of the cultivation unit corresponding to the nighttime.

[0043] 8 and 9 are plan sectional views of a plant cultivation device 1A according to another modified example of the first embodiment. In this modified example, the cultivation device 2 has only a single housing 6 that surrounds the liquid fertilizer tank 4A and the cultivation space 8A. However, the horizontal length of the cultivation device 2 in the figure is the same as that of the cultivation device 2 of the first embodiment, and the cultivation device 2 is provided with a light-shielding wall 50. In this plant cultivation device 1A, the movement control device 30 moves the light source panel 7 relative to the housing 6 to create a period during which the plants in the cultivation space 8a are illuminated with artificial light output from the light source panel 7 (the state shown in Figure 8) and a period during which the plants in the cultivation space 8a are not illuminated with artificial light output from the light source panel 7 (the state shown in Figure 9). In this plant growing device 1A, one end of the cultivation device 2 (the right end in the figure) is used as a standby position 2F for the light source panel 7. The standby position 2F is a position where the light source panel 7 cannot irradiate artificial light into the growing space 8A. During the nighttime period in the growing space 8A shown in FIG. 9, the movement control device 30 stops the light source panel 7 at the standby position 2F.

[0044] In this modified example, the above-ground portions of a plurality of plants 3 grow (are cultivated) in the cultivation space 8A. However, the above-ground portion of only one plant 3 may grow in the cultivation space 8A.

[0045] In the above embodiment and modified examples, the cultivation apparatus 2 has a pair of light source panels 7. However, the cultivation apparatus 2 may have a plurality of pairs of light source panels 7. For example, in a modified plant growing device 1B shown in Fig. 10, the cultivation device 2 has two pairs of light source panels 7. The pairs of light source panels 7 are arranged along the longitudinal direction of the growing spaces 8A, 8B. The upper part 2A of the cultivation device 2 has four cultivation spaces 8A, 8B arranged along one direction. Specifically, in the cultivation device 2, two cultivation spaces 8A and two cultivation spaces 8B are arranged alternately. The interval between the two pairs of light source panels 7 corresponds to the interval between the two cultivation spaces with the same reference numerals. In the lower part 2B of the cultivation device 2, four liquid fertilizer tanks 4A, 4B corresponding to the four cultivation spaces 8A, 8B are arranged. Each housing 6 surrounds the liquid fertilizer tank 4A or 4B and the cultivation space 8A or 8B.

[0046] The movement control device 30 synchronously moves the four light source panels 7. Alternatively, the movement control device 30 may move the four housings 6 along the longitudinal direction of the cultivation spaces 8A, 8B without moving the light source panels 7. 10, a state in which the plants in the two cultivation spaces 8A are irradiated with the artificial light output from the two pairs of light source panels 7 and a state in which the plants in the two cultivation spaces 8B are not irradiated with the artificial light output from the light source panel 7 are simultaneously created. Although not shown, by relative movement of the light source panel 7 and the housing 6, a state in which the plants in the two cultivation spaces 8B are irradiated with the artificial light output from the two pairs of light source panels 7 and a state in which the plants in the two cultivation spaces 8A are not irradiated with the artificial light output from the light source panel 7 are simultaneously created.

[0047] 11 to 13 are plan cross-sectional views of a plant growing device 1C according to yet another modified example of the first embodiment. In the plant growing device 1C, an upper portion 2A of a cultivation device 2 has three growing spaces 8A, 8B, and 8C arranged adjacent to one another along one direction. Three liquid fertilizer tanks 4A, 4B, and 4C corresponding to the three growing spaces 8A, 8B, and 8C are arranged in a lower portion 2B of the cultivation device 2. The liquid fertilizer tanks 4A, 4B, and 4C and the growing spaces 8A, 8B, and 8C are respectively arranged inside separate housings 6 arranged adjacent to one another. The cultivation device 2 has two pairs of light source panels (a pair of first light source panels 71 and a pair of second light source panels 72). The first light source panel 71 and the second light source panel 72 are arranged along the longitudinal direction of the cultivation spaces 8A, 8B, and 8C, but are arranged on different planes. The plane on which the first light source panel 71 is arranged is parallel to the plane on which the second light source panel 72 is arranged. Therefore, as shown in FIGS. 11 to 13, the first light source panel 71 and the second light source panel 72 can move along the longitudinal direction of the cultivation spaces 8A, 8B, and 8C without colliding with each other. As described later, the first light source panel 71 and the second light source panel 72 emit artificial light L having wavelength spectra different from each other.

[0048] The first light source panel 71 and the second light source panel 72 are used in common for the three cultivation spaces 8A, 8B, and 8C. The movement control device 30 moves the first light source panel 71 and the second light source panel 72 relatively to the cultivation spaces 8A, 8B, and 8C. For example, the movement control device 30 synchronously moves the pair of first light source panels 71, and also synchronously moves the pair of second light source panels 72. As a result, the movement control device 30 simultaneously creates a state in which the plant 3 inside one of the cultivation spaces 8A, 8B, 8C is illuminated with artificial light L output from the first light source panel 71, a state in which the plant 3 inside another of the cultivation spaces 8A, 8B, 8C is illuminated with artificial light L output from the second light source panel 72, and a state in which the plant 3 inside yet another of the cultivation spaces 8A, 8B, 8C is not illuminated with artificial light L.

[0049] In this modified example, the three cultivation spaces 8A, 8B, 8C share the first light source panel 71 and the second light source panel 72, and by using the first light source panel 71 and the second light source panel 72 in a time-division manner, it is possible to simultaneously place one of the cultivation spaces 8A, 8B, 8C in an environment irradiated with artificial light L from the first light source panel 71, place another of the cultivation spaces 8A, 8B, 8C in an environment irradiated with artificial light L from the second light source panel 72 having a different wavelength spectrum, and place yet another of the cultivation spaces 8A, 8B, 8C in an environment that is not irradiated with artificial light L.

[0050] Furthermore, by sharing the first light source panel 71 and the second light source panel 72 among the three cultivation spaces 8A, 8B, and 8C and using the first light source panel 71 and the second light source panel 72 in a time-division manner, it is possible to change the cultivation space between one irradiated with artificial light from the first light source panel 71, one irradiated with artificial light from the second light source panel 72, and one not irradiated with artificial light. Therefore, for the plants inside each cultivation space, it is possible to provide a period in which they are irradiated with artificial light from the first light source panel 71, a period in which they are irradiated with artificial light from the second light source panel 72 having a different wavelength spectrum, and a period in which they are not irradiated with artificial light.

[0051] Figure 11 shows a state in which a plant 3 inside the cultivation space 8A is illuminated with artificial light L output from a first light source panel 71, a state in which a plant 3 inside the cultivation space 8B is illuminated with artificial light L output from a second light source panel 72, and a state in which a plant 3 inside the cultivation space 8C is not illuminated with artificial light L. Figure 12 shows a state in which a plant 3 inside the cultivation space 8A is not illuminated with artificial light L, a state in which a plant 3 inside the cultivation space 8B is illuminated with artificial light L output from a second light source panel 72, and a state in which a plant 3 inside the cultivation space 8C is illuminated with artificial light L output from a first light source panel 71. Figure 13 shows a state in which a plant 3 inside the cultivation space 8A is illuminated with artificial light L output from the second light source panel 72, a state in which a plant 3 inside the cultivation space 8B is illuminated with artificial light L output from the first light source panel 71, and a state in which a plant 3 inside the cultivation space 8C is not illuminated with artificial light L. 11 to 13 are examples of how to use the plant cultivation device 1C, and other arrangements of the two pairs of light source panels 71, 72 for the three cultivation spaces 8A, 8B, 8C are also possible.

[0052] The first light source panel 71 and the second light source panel 72 emit artificial light L having different wavelength spectra. Specifically, the first light source panel 71 emits visible light, and the second light source panel 72 emits at least ultraviolet light. That is, the first light source panel 71 may be the same as the above-mentioned light source panel 7, and the second light source panel 72 may emit only ultraviolet light, particularly UV-A with a wavelength of 315 to 400 nm, or may emit both visible light and UV-A. When a light source panel using the LED chips 33 shown in Figures 2 to 4 is used for the second light source panel 72, all of the LED chips 33 may emit UV-A, or some of the LED chips 33 may emit visible light and some other LED chips 33 may emit UV-A. The material and thickness of the housing 6 are preferably designed so as to have high transmittance for not only visible light but also UV-A. Even when an artificial light source other than an LED panel is used, the cultivation apparatus 2 is provided with a first artificial light source that emits visible light and a second artificial light source that emits at least ultraviolet light.

[0053] Plants receive visible light and grow by photosynthesis. Visible light is essential for the growth of plants that perform photosynthesis. On the other hand, when plants receive UV-A, which has a wavelength of 315 to 400 nm, it can promote the formation of flower buds and produce beneficial substances. An example of a beneficial substance is an antioxidant, and it is known that plants exposed to ultraviolet light produce antioxidants as a defense against ultraviolet light. For example, legumes exposed to ultraviolet light produce a lot of isoflavones, and lettuce, cabbage, broccoli, etc. produced by ultraviolet light produce a lot of anthocyanins. However, if the amount of antioxidants contained in a plant is too high, the taste and aroma of the plant may be impaired. Also, if the plant spends too much energy producing antioxidants, it is considered that growth through photosynthesis will be insufficient. By sharing the first light source panel 71 that emits visible light and the second light source panel 72 that emits at least ultraviolet light in a time-sharing manner among the three cultivation spaces 8A, 8B, and 8C and appropriately setting the irradiation period of UV-A to the plants 3 in the cultivation spaces 8A, 8B, and 8C, the plants in each cultivation space can appropriately perform photosynthesis and appropriately produce beneficial substances.

[0054] 14 to 16 are plan cross-sectional views of a plant growing device 1D according to yet another modified example of the first embodiment. In the plant growing device 1D, an upper portion 2A of a cultivation device 2 has two growing spaces 8A, 8B arranged adjacent to each other along one direction. Two liquid fertilizer tanks 4A, 4B corresponding to the two growing spaces 8A, 8B are arranged in a lower portion 2B of the cultivation device 2. The combination of the cultivation space 8A and the liquid fertilizer tank 4A, and the combination of the cultivation space 8B and the liquid fertilizer tank 4B are respectively arranged inside separate housings 6 arranged adjacent to each other. The cultivation device 2 has two pairs of light source panels (a pair of first light source panels 73 and a pair of second light source panels 74). The first light source panel 73 and the second light source panel 74 are arranged along the longitudinal direction of the cultivation spaces 8A and 8B, but are arranged on different planes. The plane on which the first light source panel 73 is arranged is parallel to the plane on which the second light source panel 74 is arranged. Therefore, as shown in Figs. 14 to 16, the first light source panel 73 and the second light source panel 74 can move along the longitudinal direction of the cultivation spaces 8A and 8B without colliding with each other.

[0055] In the plant cultivation device 1D, a first light source panel 73 or a second light source panel 74 is used depending on the growth stage of the plant 3. The horizontal length of the cultivation device 2 in the figure is the same as the length of the cultivation device 2 in Figures 11 to 13 and is greater than the length of the three cultivation spaces. One end of the cultivation device 2 (the right end in the figure) is used as a standby position 2F for the light source panel 73 or 74 that is not used to irradiate the cultivation spaces 8A and 8B with artificial light.

[0056] The first light source panel 73 and the second light source panel 74 emit visible light having different wavelength spectra. Specifically, the first light source panel 73 emits visible light, and the second light source panel 74 emits visible light with fewer blue wavelength components than the visible light emitted by the first light source panel 73. For example, the first light source panel 73 may have an LED chip 33 that emits red wavelength light more strongly than other wavelengths, and an LED chip 33 that emits blue wavelength light more strongly than other wavelengths, and the second light source panel 74 may only have an LED chip 33 that emits red wavelength light more strongly than other wavelengths. Even when an artificial light source other than an LED panel is used, a first artificial light source that emits visible light and a second artificial light source that emits visible light with fewer blue wavelength components than the visible light emitted by the first artificial light source are provided in the cultivation device 2.

[0057] The two cultivation spaces 8A, 8B share the first light source panel 73 and the second light source panel 74, and by using the first light source panel 73 and the second light source panel 74 in a time-division manner, it is possible to change the cultivation space irradiated with artificial light from the first light source panel 73, the cultivation space irradiated with artificial light from the second light source panel 74, and the cultivation space not irradiated with artificial light. Therefore, for the plants inside each cultivation space, it is possible to provide a period in which they are irradiated with artificial light from the first light source panel 73, a period in which they are irradiated with artificial light from the second light source panel 74 having a different wavelength spectrum, and a period in which they are not irradiated with artificial light.

[0058] The movement control device 30 executes a step of stopping the second light source panel 74 at a standby position 2F where artificial light cannot be irradiated to either of the cultivation spaces 8A, 8B and moving the first light source panel 73 relatively to the cultivation spaces 8A, 8B, and a step of stopping the first light source panel 73 at the standby position 2F where artificial light cannot be irradiated to either of the cultivation spaces 8A, 8B and moving the second light source panel 74 to the cultivation spaces 8A, 8B.

[0059] 14 and 15 show a stage where the second light source panel 74 is stopped at the standby position 2F and the first light source panel 73 is moved relatively to the growing spaces 8A and 8B. In FIG. 14, the growing space 8A is set to a daytime state by the first light source panel 73, and the growing space 8B is set to a nighttime state. In FIG. 15, the growing space 8B is set to a daytime state by the first light source panel 73, and the growing space 8A is set to a nighttime state. Fig. 16 shows a stage where the first light source panel 73 is stopped at the standby position 2F and the second light source panel 74 is moved relatively to the growing spaces 8A and 8B. In Fig. 16, the growing space 8A is brought to a daytime state by the second light source panel 74, and the growing space 8B is brought to a nighttime state. Although not shown, when the second light source panel 74 moves relatively, the growing space 8B is brought to a daytime state by the second light source panel 74, and the growing space 8A is brought to a nighttime state. The light source panel stopped at the standby position 2F is turned off by the light emission control device 18.

[0060] There are three known types of photoreceptors in plants: phytochrome, cryptochrome, and phototropin. Phytochrome mainly performs photosynthesis in response to red light and far-red light, while cryptochrome and phototropin mainly perform photosynthesis in response to blue light. When a plant has fully grown, it no longer needs to grow thick branches and leaves, and the rate of photosynthesis slows down, so the amount of light required for growth decreases. Therefore, from an economic point of view, it is preferable to change the growing environment of the plant to one that suppresses the photosynthesis of the plant. A light source device (e.g., LED chip 33) that emits artificial light with a short wavelength (e.g., blue wavelength) consumes a lot of power, while a light source device that emits artificial light with a long wavelength (e.g., red wavelength) consumes less power. This is because, for the same number of photons, light with a short wavelength has a high amount of energy and light with a long wavelength has a low amount of energy. The first light source panel 73 and the second light source panel 74, which emit visible light having different wavelength spectra, are shared by the three cultivation spaces 8A and 8B in a time-division manner, so that each cultivation space can easily be made into an environment suitable for the growth stage. That is, before the plants have fully grown, the first light source panel 73, which emits visible light with a wide wavelength component, is moved relatively to the cultivation spaces 8A and 8B to switch between daytime and nighttime in the cultivation spaces 8A and 8B, and when the plants have fully grown, the second light source panel 74, which emits artificial light with a small blue wavelength component, is moved relatively to the cultivation spaces 8A and 8B to switch between daytime and nighttime in the cultivation spaces 8A and 8B. This allows the use of light source panels according to the growth stage of the plants. Before the plants are fully grown, the second light source panel 74 is turned off, and after the plants are fully grown, the first light source panel 73 is turned off. However, switching between daytime and nighttime in each cultivation space is achieved by the relative movement of one of the light source panels, thereby reducing the number of times the light source panels are switched on and off.

[0061] Since multiple cultivation spaces 8A, 8B share the first light source panel 73 and the second light source panel 74, the number of light source panels of the same type does not need to correspond to the number of cultivation spaces 8A, 8B. In this embodiment, a pair of first light source panels 73 and a pair of second light source panels 74 are arranged on both sides of the two cultivation spaces 8A, 8B, but it is not necessary to provide two first light source panels 73 corresponding to the two cultivation spaces 8A, 8B, and it is also not necessary to provide two second light source panels 74. Therefore, it is possible to prevent an increase in the number of light source panels.

[0062] In any of the above modified examples, the environmental control device 20 may control the cultivation space where the artificial light source irradiates visible light (corresponding to daytime) to an environment that promotes plant photosynthesis, and may control the cultivation space where the artificial light source does not irradiate visible light (corresponding to nighttime) to an environment that suppresses plant photosynthesis. 14 to 16, the environmental control device 20 may control the cultivation spaces 8A, 8B to an environment that promotes photosynthesis of plants when the movement control device 30 moves the first light source panel 73 relatively to the cultivation spaces 8A, 8B. Then, the environmental control device 20 may control the cultivation spaces 8A, 8B to an environment that suppresses photosynthesis of plants when the movement control device 30 moves the second light source panel 74 relatively to the cultivation spaces 8A, 8B. In this case, at the stage where the first light source panel 73 emitting visible light with a wide wavelength component switches the cultivation spaces 8A, 8B between daytime and nighttime, which corresponds to the stage before the plants are fully grown, the cultivation spaces 8A, 8B are controlled to an environment that promotes photosynthesis of plants. On the other hand, at the stage where the second light source panel 74 emitting artificial light with a small blue wavelength component switches the cultivation spaces 8A, 8B between daytime and nighttime, which corresponds to the stage where the plants are fully grown, the cultivation spaces 8A, 8B are controlled to an environment that suppresses photosynthesis of plants. As described above, an environment that suppresses photosynthesis of plants usually requires low operating costs, so that the operating costs at the stage where the plants are fully grown can be reduced.

[0063] Figures 17 and 18 show a plant growing device 100 according to a second embodiment of the present invention. In Figures 17 and 18, the same reference numerals are used to indicate components common to the first embodiment, and these components will not be described in detail. The plant growing device 100 has a cultivation device 102 for growing a large number of plants. The cultivation device 102 has an upper part 2A and a lower part 2B disposed below the upper part 2A. In plant cultivation device 100, a single light source panel (artificial light source) 77 is disposed above cultivation spaces 8A, 8B arranged closely to each other. In other words, light source panel 77 is disposed in the vicinity of cultivation spaces 8A, 8B.

[0064] Two liquid fertilizer tanks 4A, 4B corresponding to the two cultivation spaces 8A, 8B are arranged in the lower part 2B of the cultivation device 102. The combination of the cultivation space 8A and the liquid fertilizer tank 4A, and the combination of the cultivation space 8B and the liquid fertilizer tank 4B are arranged in separate housings 6 arranged close to each other. In this embodiment, in each of the cultivation spaces 8A, 8B, the above-ground parts (i.e., stems and leaves) of multiple plants 3 grow (are cultivated). However, the above-ground part of only one plant 3 may grow in each of the cultivation spaces 8A, 8B.

[0065] As in the first embodiment, each housing 6 defines a closed cultivation space 8 A or 8 B. The housing 6 is made of a light-transmitting material, such as glass or a transparent resin. Each housing 6 has an upper wall 6b interposed between the cultivation space 8A or 8B and the light source panel 77. The upper wall 6b is formed flat and is disposed horizontally so as to be parallel to the light source panel 77.

[0066] The light source panel 77 emits artificial light L for growing the plants 3. The light source panel 77 is disposed above the growth spaces 8A, 8B, and supplies artificial light L from above to the plants 3 in the growth spaces 8A, 8B. The plant growth device 100, which irradiates artificial light L from above downward in this manner, is suitable for applying artificial light L to plants 3 at a growth stage having leaves that spread out widely in horizontal or diagonal directions compared to their height. The light source panel 77 is used in common to the multiple cultivation spaces 8A, 8B, and supplies artificial light L to the cultivation spaces 8A, 8B. However, the cultivation spaces 8A, 8B use these light source panels 77 in a time-division manner (i.e., during different periods).

[0067] The housing 6, particularly the upper wall 6b, suppresses or inhibits heat radiation and heat conduction from the light source panel 77, which is a heat source, and prevents overheating of the cultivation spaces 8A, 8B. In this embodiment, each housing 6 surrounds the entirety of the growing space 8A or 8B. However, each housing 6 does not necessarily have to surround the entirety of the growing space 8A or 8B. For example, the end walls of each housing 6 may be omitted, and the side walls may not be transparent. The portion of each housing 6 that is present in the lower portion 2B and surrounds the liquid fertilizer tank 4A or 4B may not be transparent.

[0068] As in the first embodiment, in order to prevent each light source panel 77 from overheating, any one of a blower (not shown), a refrigerant pipe or refrigerant chamber (not shown), and fins (not shown) may be provided.

[0069] The height from the plant support panel 5 to the upper wall 6b of the housing 6 is set to a size that allows artificial light L to be applied almost evenly and sufficiently to each leaf of the plant 3 that has grown to a certain extent. However, it is preferable that the height of the upper wall 6b is set so as to restrict excessive growth of the plant 3 in the vertical direction. In other words, it is preferable that the position of the upper wall 6b with respect to the plant 3 is determined so as to restrict the vertical growth of the leaves of the plant 3 cultivated inside the cultivation spaces 8A, 8B. Specifically, it is preferable that the height of the upper wall 6b is set smaller than the maximum height that the leaves of the plant 3 are predicted to reach when they grow to their maximum extent, assuming that the housing 6 does not exist. In this case, since the upper wall 6b restricts the excessive growth of the leaves of the plant 3, the plant 3 can be grown in a small space (small height).

[0070] The movement control device 30 controls a movement mechanism (not shown) to move the light source panel 7 relative to the housing 6 (i.e., to move the light source panel 7 relative to the cultivation spaces 8A and 8B). The light source panel 77 is used in common for the two cultivation spaces 8A and 8B. The movement control device 30 moves the light source panel 77 relative to the housing 6 and thus the cultivation spaces 8A and 8B so as to alternately create a period in which the plant 3 in one of the cultivation spaces 8A and 8B is irradiated with the artificial light L output from the light source panel 77 and a period in which the plant 3 in the other of the cultivation spaces 8A and 8B is not irradiated with the artificial light L. In addition, the cultivation spaces irradiated with artificial light and those not irradiated with artificial light can be alternately changed. By sharing the light source panel 77 between the two cultivation spaces 8A and 8B and using the light source panel 77 in a time-division manner, it is possible to simultaneously place one of the cultivation spaces 8A and 8B in an environment irradiated with artificial light L from the light source panel 77 and place the other of the cultivation spaces 8A and 8B in an environment not irradiated with artificial light L. FIG. 18 shows a state in which the plant 3 in the cultivation space 8A is irradiated with artificial light L output from the light source panel 77 and the plant 3 in the cultivation space 8B is not irradiated with artificial light L. Although not shown, it is also possible to conversely irradiate the plant 3 in the cultivation space 8B with artificial light L output from the light source panel 77 and not irradiate the plant 3 in the cultivation space 8A with artificial light L. In this way, it is possible to alternate between periods in which the plants in each cultivation space are irradiated with artificial light and periods in which they are not irradiated with artificial light.

[0071] The movement control device 30 may move the light source panel 77 from the vicinity of one of the cultivation spaces 8A, 8B to the vicinity of the other in a 12-hour cycle, for example. In this case, in each of the cultivation spaces 8A, 8B, 12 hours of the day are daytime and the other 12 hours are nighttime. However, the movement control device 30 may move the light source panel 77 from one of the growing spaces 8A, 8B to the other in other cycles. For example, even if the light source panel 77 is moved from one of the growing spaces 8A, 8B to the other in a 6-hour cycle, a 4-hour cycle, or a 3-hour cycle, in each of the growing spaces 8A, 8B, a total of 12 hours are daytime and a total of 12 hours are nighttime.

[0072] According to this embodiment, the housing 6 thermally separates the growing spaces 8A, 8B from the light source panel 77, and the growing spaces 8A, 8B are less susceptible to the heat. In other words, the housing 6 prevents the growing spaces 8A, 8B from overheating. This allows the air conditioning system 12 to reduce the energy required to control the air temperature in the growing spaces 8A, 8B, and makes it easy to control the growing spaces 8A, 8B to an environment suitable for the plants to be cultivated.

[0073] In addition, by moving the light source panel 77 relative to the cultivation spaces 8A and 8B by the movement control device 30, it is possible to simultaneously create a state in which plants in one of the cultivation spaces 8A and 8B are irradiated with artificial light (a state corresponding to daytime) and a state in which plants in the other of the cultivation spaces 8A and 8B are not irradiated (a state corresponding to nighttime). That is, by sharing the light source panel 77 between the multiple cultivation spaces 8A and 8B and using the light source panel 77 in a time-division manner (i.e., during different periods), it is possible to simultaneously place one of the cultivation spaces 8A and 8B in an environment irradiated with artificial light and place the other of the cultivation spaces 8A and 8B in an environment not irradiated with artificial light. In addition, by changing the cultivation spaces irradiated with artificial light and the cultivation spaces not irradiated with artificial light, it is possible to alternate periods in which the plants in each cultivation space are irradiated with artificial light and periods in which they are not irradiated with artificial light. The number of light source panels 77 does not need to correspond to the number of the growing spaces 8A, 8B. In this embodiment, a single light source panel 77 can be used to simultaneously realize a daytime state in one of the two growing spaces 8A, 8B and a nighttime state in the other of the two growing spaces 8A, 8B. Therefore, an increase in the number of light source panels 77 can be prevented.

[0074] In addition, since the multiple cultivation spaces 8A, 8B use the light source panel 77 in a time-division manner, the light source panel 77 can be continuously driven. This reduces the number of times the light source panel 77 is switched on and off, thereby shortening the period during which the light source panel 77 is not in use. In addition, when the artificial light source is a fluorescent lamp or a cold cathode fluorescent tube, it is possible to reduce failures caused by switching on and off, and to save power consumption. However, it is not necessary to drive the light source panel 77 permanently. Many types of plants flower when they sense a change in day length. Therefore, even if the light source panel 77 is moved from the vicinity of one of the cultivation spaces 8A, 8B to the vicinity of the other in a 12-hour cycle, for example, an off time during which the light source panel 77 does not emit light may be provided to bring about a change in day length.

[0075] The movement control device 30 moves the light source panel 77 along the longitudinal direction of the growth spaces 8A, 8B relative to the fixed growth spaces 8A, 8B. However, the movement control device 30 may not move the light source panel 77, but may move the housing 6 surrounding the liquid fertilizer tanks 4A, 4B together with the cultivation spaces 8A, 8B along the longitudinal direction of the cultivation spaces 8A, 8B. In any case, the movement control device 30 moves the light source panel 7 relative to the housing 6. The variations described above regarding the first embodiment may also be applied to this embodiment.

[0076] Next, a plant growing device according to a third embodiment of the present invention will be described with reference to Figures 19 to 24. In Figures 19 to 24, the same reference numerals are used to indicate components common to the first embodiment, and these components will not be described in detail. As shown in Fig. 19, the plant cultivation device 200 according to the third embodiment has a plurality of cultivation units 202A, 202B. The cultivation units 202A, 202B are arranged alternately. Each of the cultivation units 202A, 202B has a housing unit 60, a plant support panel 5, and a liquid fertilizer tank unit 90. 19 and 20 , the plant cultivation device 200 has a light source support unit 80, a plurality of housing units 60, a plant support panel 5, a plurality of liquid fertilizer tank units 90, and a lower housing 95. In FIG. 19 , the light source support unit 80 is shown by an imaginary line, and the outline of the light source support unit 80 matches the lower housing 95.

[0077] The light source support unit 80 is used in common by the multiple cultivation units 202A, 202B and covers the multiple housing units 60 in the cultivation units 202A, 202B. The lower housing 95 is also used in common by the multiple cultivation units 202A, 202B and covers the multiple liquid fertilizer tank units 90 in the cultivation units 202A, 202B. Inside the lower housing 95, a lower space 2D in which the multiple liquid fertilizer tank units 90 are arranged is provided. The multiple housing units 60 and the multiple liquid fertilizer tank units 90 are arranged in a direction perpendicular to the plane of the paper in FIG. The plant support panels 5 are provided in each of the cultivation units 202A, 202B, and are arranged in a vertical direction in the plane of the page in Fig. 20. The plant support panels 5 are interposed between one liquid fertilizer tank unit 90 and one housing unit 60, and extend horizontally. The plant support panels 5 are not shown in Fig. 19.

[0078] Please refer to the exploded cross-sectional view of FIG. The light source support unit 80 is formed from a rigid material and has an upper wall 81, a side wall 82, a partition wall 83, and an end wall 84. The side walls 82 are arranged parallel to each other on both sides of the light source support unit 80, extend in the vertical direction, and are connected to the upper wall 81. The partition wall 83 is arranged parallel to the side wall 82, extends in the vertical direction, and is connected to the upper wall 81. The end wall 84 is arranged perpendicular to the side wall 82 and the partition wall 83, extends in the vertical direction, and is connected to the upper wall 81. A space 85 is provided between the side wall 82 and the partition wall 83 , and a space 85 is also provided between the pair of partition walls 83 . A pair of light source panels 7 are arranged in each space 85. One light source panel 7 is supported on the inner surface of the side wall 82, and a light source panel 7 is supported on each of both sides of the partition wall 83. The light source panel 7 is movable in the direction perpendicular to the paper surface of Figures 20 and 21 (the vertical direction in Figure 19) by a moving mechanism (not shown). In this embodiment, the light source panel 7 is supported by a side wall 82 and a partition wall 83. However, the light source panel 7 may be supported movably on the lower surface of the upper wall 81, i.e., on the ceiling surface 86 of each space 85.

[0079] Each housing unit 60 has a plurality of housings 61 corresponding to the housings 6 in the first and second embodiments. Each housing 61 is made of a light-transmitting material, such as glass or transparent resin. A cultivation space 62 is defined inside each housing 61. In each cultivation space 62, the above-ground portions of a plurality of plants 3 grow (are cultivated). However, in each cultivation space 62, the above-ground portion of only one plant 3 may grow. Each housing 61 has a pair of side walls 63, a top wall 65, and an end wall 66, which define a growing space 62. The side walls 63 are arranged parallel to each other, extend in the vertical direction, and are connected to the top wall 65. The end wall 66 is arranged perpendicular to the side walls 62, extends in the vertical direction, and is connected to the top wall 65. The lower ends of adjacent housings 61 are connected by a horizontal connecting wall 67.

[0080] The trunks of multiple plants 3 pass through each plant support panel 5 , and each plant support panel 5 supports these plants 3 .

[0081] The liquid fertilizer tank unit 90 has a plurality of liquid fertilizer tanks 91 and pipes 92 connecting these liquid fertilizer tanks 91. Liquid fertilizer can circulate between the plurality of liquid fertilizer tanks 91 through the pipes 92. Inside each liquid fertilizer tank 91, the roots of one plant 3 are placed, and the roots grow here.

[0082] The plant cultivation device 200 is assembled from the disassembled state shown in Fig. 21 as shown in Fig. 22. During assembly, the seedlings of the plants 3 are inserted into the holes in the plant support panel 5, and the roots of the seedlings of the plants 3 are placed in the liquid fertilizer tank 91 of the liquid fertilizer tank unit 90. The liquid fertilizer tank unit 90 is placed in the lower space 2D inside the lower housing 95. During assembly, the above-ground portion of the seedling of the plant 3 is placed in the growing space 62 inside each housing 61 of the housing unit 60. Each housing 61 is placed in the space 85 of the light source support unit 80, and the light source panels 7 are placed on both sides of each housing 61.

[0083] After the stage shown in Fig. 22, the plant 3 is grown in the plant growing device 200. As shown in Fig. 20, when the plant 3 grows, the light source support unit 80 is removed. Then, as shown in Fig. 23, the housing unit 60 is moved upward. In this way, harvesting is possible.

[0084] As shown in FIG. 19, a plant growing device 200 includes a nutrient solution supplying system 10, an air conditioning system 12, a light emission control device 18, and a movement control device 30.

[0085] In Fig. 19, the open arrows indicate the flow of liquid fertilizer supplied from the nutrient solution supply system 10 and collected into the nutrient solution supply system 10. The liquid fertilizer first flows from the nutrient solution supply system 10 into the liquid fertilizer tank unit 90 of the cultivation unit 202A that is closest to the nutrient solution supply system 10. In the liquid fertilizer tank unit 90, the liquid fertilizer tanks 91 are connected by pipes 92, so that the liquid fertilizer is distributed throughout all of the liquid fertilizer tanks 91. In the cultivation unit 202A, the liquid fertilizer flows from left to right in Fig. 19. Next, the liquid fertilizer flows from the liquid fertilizer tank unit 90 of the cultivation unit 202A into the liquid fertilizer tank unit 90 of the adjacent cultivation unit 202B. Here too, the liquid fertilizer spreads throughout all of the liquid fertilizer tanks 91. In the cultivation unit 202B, the liquid fertilizer flows from right to left in FIG. Next, the liquid fertilizer flows from the liquid fertilizer tank unit 90 of the cultivation unit 202B into the liquid fertilizer tank unit 90 of the adjacent cultivation unit 202A. Here too, the liquid fertilizer spreads throughout all of the liquid fertilizer tanks 91. In the cultivation unit 202A, the liquid fertilizer flows from left to right in FIG.

[0086] Next, the liquid fertilizer flows from the liquid fertilizer tank unit 90 of the cultivation unit 202A into the liquid fertilizer tank unit 90 of the cultivation unit 202B, which is the farthest from the liquid fertilizer tank unit 90. Here too, the liquid fertilizer spreads throughout all of the liquid fertilizer tanks 91. In the cultivation unit 202B, the liquid fertilizer flows from right to left in FIG. Finally, the liquid fertilizer is collected from the liquid fertilizer tank unit 90 of the cultivation unit 202B, which is the farthest from the liquid fertilizer tank unit 90, to the nutrient solution supply system 10. In this manner, the liquid fertilizer flows through the liquid fertilizer tanks 91 in all of the cultivation units 202A and 202B.

[0087] As described above, in each liquid fertilizer tank unit 90, the liquid fertilizer tanks 91 are connected by the pipes 92, so that liquid fertilizer is distributed throughout all of the liquid fertilizer tanks 91. Therefore, each liquid fertilizer tank unit 90 can be regarded as one liquid fertilizer tank in which liquid fertilizer is stored and the roots of multiple plants 3 are placed. The nutrient solution supply system (liquid fertilizer control system) 10 controls at least one of the concentration and temperature of the liquid fertilizer inside the liquid fertilizer tank unit 90. The liquid fertilizer tank unit 90 and the liquid fertilizer tank unit 90 are used in common for multiple cultivation spaces 62 corresponding to multiple housings 61. Therefore, the control of the liquid fertilizer can be simplified compared to the case where a liquid fertilizer tank is provided for each of the multiple cultivation spaces 62 and the concentration or temperature of the liquid fertilizer inside these liquid fertilizer tanks is controlled.

[0088] 19 and 20, the black arrows indicate the flow of air supplied from the air conditioning system 12 and collected by the air conditioning system 12. The air first flows from the air conditioning system 12 into the lower space 2D of the lower housing 95. The plant support panel 5 is breathable, and there are gaps around the liquid fertilizer tank 91 that allow ventilation. Therefore, as shown in FIG. 24, the air can flow from the lower space 2D into the growth spaces 62 inside each housing 61, and also flow out from the growth spaces 62 inside each housing 61 into the lower space 2D. The air that has circulated through the multiple growth spaces 62 in this manner is collected by the air conditioning system 12.

[0089] The light emission control device 18 controls the light emission of the light source panel 7. For example, the light emission control device 18 turns the light source panel 7 on and off.

[0090] The movement control device 30 controls a movement mechanism (not shown) to synchronously move the plurality of light source panels 7 back and forth in the vertical direction of Fig. 19. As shown in Fig. 19, the period during which the light source panel 7 stops at the cultivation unit 202A and irradiates the cultivation space 62 inside the housing 61 in the cultivation unit 202A is a daytime period for the plants 3 in these cultivation spaces 62. This period is a nighttime period for the plants 3 in these cultivation spaces 62 because the cultivation space inside the housing 61 in the cultivation unit 202B is not irradiated. Although not shown, the period during which the moved light source panel 7 stops at the cultivation unit 202B and irradiates the cultivation space 62 inside the housing 61 in the cultivation unit 202B is a daytime period for the plants 3 in these cultivation spaces 62. This period is a nighttime period for the plants 3 in these cultivation spaces 62 because the cultivation space inside the housing 61 in the cultivation unit 202A is not irradiated. In this way, it is possible to create a period during which the plants in each cultivation space 62 are irradiated with artificial light (period corresponding to daytime) and a period during which they are not irradiated (period corresponding to nighttime). In addition, by sharing the light-emitting panel 7 among the multiple cultivation spaces 62 of the cultivation units 202A and 202B and using the light-emitting panel 7 in a time-division manner (i.e., during different periods), it is possible to simultaneously place the cultivation space 62 of the cultivation unit 202A or 202B in an environment irradiated with artificial light and place the cultivation space 62 of the cultivation unit 202B or 202A in an environment not irradiated with artificial light.

[0091] In this embodiment, the air conditioning system 12 circulates air to all of the cultivation spaces 62 of the cultivation units 202A and 202B, and the nutrient solution supply system 10 circulates liquid fertilizer to all of the liquid fertilizer tanks 91 of the cultivation units 202A and 202B. However, the air conditioning system 12 may separately control the air conditioning of the cultivation space 62 of the cultivation unit 202A and the cultivation space 62 of the cultivation unit 202B. Also, the nutrient solution supply system 10 may separately control the concentration of liquid fertilizer in the liquid fertilizer tank unit 90 of the cultivation unit 202A and the concentration of liquid fertilizer in the liquid fertilizer tank unit 90 of the cultivation unit 202B. In this case, it is possible to perform the environmental control adapted to the daytime and nighttime periods described above. It is also possible to perform the environmental control adapted to the growth stage of the plant 3 described above.

[0092] Although the present invention has been shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that changes may be made in form and detail without departing from the scope of the invention as set forth in the appended claims. Such changes, modifications and alterations are intended to be embraced within the scope of the invention.

[0093] The movement control device 30 and the environment control device 20 are not limited to a computer processor. All or a part of them may be executed by hardware instead of a processor, or may be executed by a programmable logic device such as an FPGA (Field Programmable Gate Array) or a DSP (Digital Signal Processor).

[0094] The above embodiments and modifications may be combined as long as they are not inconsistent. Aspects of the invention are also described in the following numbered clauses. Article 1. A plant growing device for growing plants, At least one housing formed from a light-transmitting material and defining an enclosed growing space in which an above-ground portion of at least one plant is grown; at least one artificial light source disposed near the housing and emitting artificial light for growing the plant; a movement control device that moves the artificial light source relative to the housing so as to create a period during which the plants in the cultivation space are irradiated with the artificial light output from the artificial light source and a period during which the plants in the cultivation space are not irradiated with the artificial light output from the artificial light source; A plant growing device comprising: Clause 2. The movement control device moves the artificial light source. 2. A plant growing device according to claim 1, characterized in that Clause 3. The movement control device moves the housing. 2. A plant growing device according to claim 1, characterized in that

[0095] Clause 4. A plurality of enclosures arranged adjacent to each other, each defining a growing space; The at least one artificial light source is used in common for a plurality of growing spaces corresponding to the plurality of housings; The movement control device moves the artificial light source relative to the plurality of cultivation spaces so that the artificial light output from the at least one artificial light source is supplied to the different cultivation spaces for different periods of time. 4. A plant growing device according to any one of claims 1 to 3, characterized in that In this case, by using the artificial light source in a time-sharing manner (i.e., for different periods), one cultivation space can be placed in an environment irradiated with artificial light and another cultivation space can be placed in an environment not irradiated with artificial light at the same time. In addition, by changing the cultivation space irradiated with artificial light and the cultivation space not irradiated with artificial light, it is possible to provide a period in which artificial light is irradiated and a period in which artificial light is not irradiated for plants in each cultivation space. By sharing at least one artificial light source among multiple cultivation spaces, the number of artificial light sources does not need to correspond to the number of cultivation spaces. For example, a daytime state of one cultivation space and a nighttime state of another cultivation space can be simultaneously realized using one artificial light source. Therefore, an increase in the number of artificial light sources can be prevented. In addition, since the multiple cultivation spaces use the artificial light source in a time-sharing manner, the artificial light source can be operated continuously. Therefore, the number of times the artificial light source is switched on and off can be reduced, and the period during which the artificial light source is not used can be reduced, and depending on the type of light source, it is possible to reduce breakdowns caused by switching on and off and save power consumption.

[0096] Clause 5. The at least one artificial light source comprises a first artificial light source and a second artificial light source, the first artificial light source and the second artificial light source emitting artificial light having different wavelength spectra from each other; The first artificial light source and the second artificial light source are used in common for a plurality of cultivation spaces corresponding to the plurality of enclosures; The movement control device moves the first artificial light source and the second artificial light source relatively to the plurality of cultivation spaces so as to create, for the plants in each cultivation space, a period in which the plants are irradiated with the artificial light output from the first artificial light source, a period in which the plants are irradiated with the artificial light output from the second artificial light source, and a period in which the plants are not irradiated with the artificial light. 5. A plant growing device according to claim 4, characterized in that In this case, by sharing the first artificial light source and the second artificial light source among multiple cultivation spaces and using the first artificial light source and the second artificial light source in a time-division manner, it is possible to provide each cultivation space with a period irradiated with artificial light from the first artificial light source, a period irradiated with artificial light from the second artificial light source having a different wavelength spectrum, and a period not irradiated with artificial light. It is also possible to change the cultivation space irradiated with artificial light from the first artificial light source, the cultivation space irradiated with artificial light from the second artificial light source, and the cultivation space not irradiated with artificial light.

[0097] Clause 6. The first artificial light source emits visible light and the second artificial light source emits at least ultraviolet light. 6. A plant growing device according to claim 5, characterized in that Visible light is essential for the growth of plants that perform photosynthesis. On the other hand, when plants receive UV-A, which has a wavelength of 315 to 400 nm among ultraviolet rays, the formation of flower buds may be promoted and useful substances (e.g., antioxidants) may be produced. By sharing a first artificial light source that emits visible light and a second artificial light source that emits at least ultraviolet light in a time-sharing manner among multiple cultivation spaces and appropriately setting the irradiation period of ultraviolet light to plants in the cultivation spaces, it becomes possible for plants in each cultivation space to properly perform photosynthesis and properly produce useful substances. Here, the second artificial light source may emit not only ultraviolet light but also visible light.

[0098] Clause 7. The first artificial light source emits visible light, and the second artificial light source emits visible light having less blue wavelength components than the visible light emitted by the first artificial light source; The movement control device executes a step of stopping the second artificial light source at a position where artificial light cannot be irradiated to any of the plurality of cultivation spaces and moving the first artificial light source relatively to the plurality of cultivation spaces, and a step of stopping the first artificial light source at a position where artificial light cannot be irradiated to any of the plurality of cultivation spaces and moving the second artificial light source relatively to the plurality of cultivation spaces. 6. A plant growing device according to claim 5, characterized in that At a stage where the plant has fully grown, the amount of light required for growth is reduced because the plant no longer needs to grow lushly and the rate of photosynthesis slows down. Therefore, it is preferable from an economical point of view to change the plant growth environment to one that suppresses the plant's photosynthesis. A light source device that emits artificial light of a short wavelength (e.g., blue wavelength) consumes a large amount of power, while a light source device that emits artificial light of a long wavelength (e.g., red wavelength) consumes a small amount of power. Therefore, at a stage before the plant has fully grown, a first artificial light source that emits visible light with a wide wavelength component can be moved relatively to the multiple growth spaces to switch between daytime and nighttime in each growth space, and at a stage when the plant has fully grown, a second artificial light source that emits artificial light with a small amount of blue wavelength component can be moved relatively to the multiple growth spaces to switch between daytime and nighttime in each growth space. This allows the use of light sources according to the growth stage of the plant. Before the plants are fully grown, the second artificial light source is turned off, and after the plants are fully grown, the first artificial light source is turned off. However, switching between daytime and nighttime in each cultivation space is achieved by the relative movement of one of the artificial light sources, thereby reducing the number of times the artificial light sources are switched on and off.

[0099] Clause 8. The cultivation space where the artificial light source irradiates visible light is controlled to an environment that promotes photosynthesis of plants, and the cultivation space where the artificial light source does not irradiate visible light is controlled to an environment that suppresses photosynthesis of plants. 8. A plant growing device according to any one of clauses 1 to 7, characterized in that In this case, during the period corresponding to daytime when the cultivation space receives visible light, the cultivation space is controlled to an environment that promotes plant photosynthesis. On the other hand, during the period corresponding to nighttime when the cultivation space does not receive visible light, the cultivation space is controlled to an environment that suppresses plant photosynthesis. Since an environment that suppresses plant photosynthesis usually requires low operating costs, nighttime operating costs can be reduced.

[0100] Clause 9. The present invention further includes an environmental control device that controls the environments of the multiple cultivation spaces to promote photosynthesis of plants in a stage where the movement control device moves the first artificial light source relatively to the multiple cultivation spaces, and controls the environments of the multiple cultivation spaces to suppress photosynthesis of plants in a stage where the movement control device moves the second artificial light source relatively to the multiple cultivation spaces. 8. A plant growing device according to claim 7, characterized in that In this case, at a stage before the plants are fully grown, in which the first artificial light source emitting visible light with a wide wavelength component switches between day and night in the multiple cultivation spaces, the cultivation spaces are controlled to an environment that promotes plant photosynthesis. On the other hand, at a stage when the second artificial light source emitting artificial light with a small blue wavelength component switches between day and night in the multiple cultivation spaces, in which the plants are fully grown, the cultivation spaces are controlled to an environment that suppresses plant photosynthesis. Since an environment that suppresses plant photosynthesis usually requires low operating costs, it is possible to reduce operating costs at the stage when the plants are fully grown.

[0101] Clause 10. The artificial light source irradiates the plants in the growing space with artificial light from the side. 10. A plant growing device according to any one of clauses 1 to 9, characterized in that In this case, since the artificial light source irradiates the plant from the side, the artificial light can be applied as evenly as possible to both the upper and lower leaves of a plant at a growth stage having many leaves overlapping vertically.

[0102] Article 11. A liquid fertilizer tank in which liquid fertilizer is stored and in which the roots of a plurality of plants are placed; A liquid fertilizer control system is provided for controlling at least one of the concentration and temperature of the liquid fertilizer in the liquid fertilizer tank, The liquid fertilizer tank and the liquid fertilizer control system are used in common for the plurality of growing spaces corresponding to the plurality of housings. 10. A plant growing device according to any one of clauses 4 to 7 and 9, characterized in that In this case, the liquid fertilizer tank and the liquid fertilizer control system are used in common for a plurality of cultivation spaces, thereby simplifying the control of the liquid fertilizer.

[0103] Article 12. A method for cultivating a plant, comprising: Relatively moving at least one housing formed of a light-transmitting material and defining an enclosed cultivation space in which an above-ground portion of at least one plant is cultivated, and at least one artificial light source emitting artificial light for growing the plant, to create a period during which the plant in the cultivation space is irradiated with the artificial light output from the artificial light source; moving the housing and the artificial light source relative to one another to create a period during which the plants in the cultivation space are not irradiated with the artificial light output from the artificial light source; A plant growing method comprising: [Explanation of symbols]

[0104] L... artificial light, 1, 1A, 1B, 1C, 1D, 100, 200... plant cultivation device, 2, 102... cultivation device, 3... plant, 4A, 4B, 4C... liquid fertilizer tank, 6... housing, 7, 77... light source panel (artificial light source), 8A, 8B, 8C... cultivation space, 10... nutrient solution supply system (liquid fertilizer control system), 20... environment control device, 30... movement control device, 71, 73... first light source panel, 72, 74... second light source panel, 77... light source panel, 202A, 202B... cultivation unit, 60... housing unit, 61... housing, 90... liquid fertilizer tank unit (liquid fertilizer tank), 62... cultivation space

Claims

1. A plant growing device for growing plants, At least one housing formed from a light-transmitting material and defining an enclosed growing space in which an above-ground portion of at least one plant is grown; at least one artificial light source disposed near the housing and emitting artificial light for growing the plant; a movement control device that moves the artificial light source relative to the housing so as to create a period during which the plants in the cultivation space are irradiated with the artificial light output from the artificial light source and a period during which the plants in the cultivation space are not irradiated with the artificial light output from the artificial light source; A plant growing device comprising:

2. The movement control device moves the artificial light source.

2. The plant growing device according to claim 1 .

3. The movement control device moves the housing.

2. The plant growing device according to claim 1 .

4. A plurality of housings arranged adjacent to each other, each housing defining a growing space; The at least one artificial light source is used in common for a plurality of growing spaces corresponding to the plurality of housings; The movement control device moves the artificial light source relative to the plurality of cultivation spaces so that the artificial light output from the at least one artificial light source is supplied to the different cultivation spaces for different periods of time.

4. The plant growing device according to claim 1, wherein the plant growing device is a device for growing a plant.

5. the at least one artificial light source comprises a first artificial light source and a second artificial light source, the first artificial light source and the second artificial light source emitting artificial light having different wavelength spectra from each other; The first artificial light source and the second artificial light source are used in common for a plurality of cultivation spaces corresponding to the plurality of enclosures; The movement control device moves the first artificial light source and the second artificial light source relatively to the plurality of cultivation spaces so as to create, for the plants in each cultivation space, a period in which the plants are irradiated with the artificial light output from the first artificial light source, a period in which the plants are irradiated with the artificial light output from the second artificial light source, and a period in which the plants are not irradiated with the artificial light.

5. The plant growing device according to claim 4.

6. The first artificial light source emits visible light and the second artificial light source emits at least ultraviolet light.

6. The plant growing device according to claim 5.

7. The first artificial light source emits visible light, and the second artificial light source emits visible light having fewer blue wavelength components than the visible light emitted by the first artificial light source, The movement control device executes a step of stopping the second artificial light source at a position where artificial light cannot be irradiated to any of the plurality of cultivation spaces and moving the first artificial light source relatively to the plurality of cultivation spaces, and a step of stopping the first artificial light source at a position where artificial light cannot be irradiated to any of the plurality of cultivation spaces and moving the second artificial light source relatively to the plurality of cultivation spaces.

6. The plant growing device according to claim 5.

8. The cultivation space where the artificial light source irradiates visible light is controlled to an environment that promotes photosynthesis of plants, and the cultivation space where the artificial light source does not irradiate visible light is controlled to an environment that suppresses photosynthesis of plants.

4. The plant growing device according to claim 1, wherein the plant growing device is a device for growing a plant.

9. The device further includes an environmental control device that controls the plurality of cultivation spaces to have an environment that promotes photosynthesis of plants in a stage where the movement control device moves the first artificial light source relatively to the plurality of cultivation spaces, and controls the plurality of cultivation spaces to have an environment that suppresses photosynthesis of plants in a stage where the movement control device moves the second artificial light source relatively to the plurality of cultivation spaces.

8. The plant growing device according to claim 7.

10. The artificial light source irradiates the plants in the growing space with artificial light from a side.

4. The plant growing device according to claim 1, wherein the plant growing device is a device for growing a plant.

11. a liquid fertilizer tank that contains liquid fertilizer and in which the roots of a plurality of plants are placed; A liquid fertilizer control system is provided for controlling at least one of the concentration and temperature of the liquid fertilizer in the liquid fertilizer tank, The liquid fertilizer tank and the liquid fertilizer control system are used in common for the plurality of growing spaces corresponding to the plurality of housings.

5. The plant-growing device according to claim 4.

12. A method for cultivating a plant, comprising: Relatively moving at least one housing formed of a light-transmitting material and defining an enclosed cultivation space in which an above-ground portion of at least one plant is cultivated, and at least one artificial light source emitting artificial light for growing the plant, to create a period during which the plant in the cultivation space is irradiated with the artificial light output from the artificial light source; moving the housing and the artificial light source relative to one another to create a period during which the plants in the cultivation space are not irradiated with the artificial light output from the artificial light source; A plant growing method comprising:

Images