Plant growing device and method

Abstract

The present invention is for preventing damage to a plant due to light having a specific wavelength component included in sunlight.　This plant growing device comprises: a sunlight guide mechanism for guiding sunlight to a plant 3; a control mechanism 8 for controlling wavelength components of sunlight SL to remove a specific wavelength component from the sunlight SL before irradiation of the plant 3; and a light source unit 7 capable of irradiating the plant 3 with artificial light for growing the plant 3.

Description

Plant cultivation device and method

[0001] The present invention relates to a plant cultivation device and method for cultivating plants using both sunlight and artificial light.

[0002] Conventionally, as an apparatus for growing plants using a combination of sunlight and artificial light, for example, a plant growing apparatus is disclosed in Patent Document 1. This plant growing apparatus allows sunlight to enter during the day to promote photosynthesis in plants, and when the amount of sunlight entering the apparatus is insufficient for photosynthesis, such as on cloudy or rainy days, a supplementary light device is used to make up for the shortage.

[0003] Japanese Unexamined Patent Publication No. 1-160435

[0004] However, the plant growing device of Patent Document 1 is configured to allow sunlight to directly strike the plants, resulting in light containing specific wavelength components such as ultraviolet and infrared rays being incident on the plants. Ultraviolet rays, which have short wavelengths in particular, are harmful to plant cells, and infrared rays can overheat plants and cause damage from heat. The present invention was made in light of the above, and aims to prevent damage to plants caused by light containing specific wavelength components in sunlight.

[0005] To solve the above problems, one aspect of the plant growing device according to the present invention is a plant growing device that grows plants using artificial light, comprising: a sunlight guiding mechanism that guides sunlight to the plant; a control mechanism that controls wavelength components of the sunlight to remove specific wavelength components from the sunlight before it is irradiated onto the plant; and an artificial light source that can irradiate the plant with artificial light for growing the plant. The plant growing device may also be configured to include an irradiance measurement unit that measures the amount of sunlight irradiated onto the plant after the control mechanism has removed the wavelength components; and a control unit that, when the irradiance measured by the irradiance measurement unit is less than the amount of irradiation required for growing the plant, controls the irradiation of the artificial light from the artificial light source onto the plant so as to reach the required amount of irradiation. In the plant growing device, the control mechanism may remove infrared wavelength components from the sunlight. In the plant growing device, the control mechanism may remove ultraviolet wavelength components from the sunlight.

[0006] The above-mentioned plant growing device may further include a plurality of growing spaces, each of which grows at least one portion of the plant above the roots; a moving mechanism which moves each of the growing spaces to a predetermined position within the sunlight irradiation range; and a moving control unit which controls the moving mechanism, wherein the irradiation amount measuring unit measures the amount of sunlight irradiated onto the plant grown in each of the growing spaces from which the specific wavelength component has been removed, and the moving control unit acquires the amount of irradiation onto the plant grown in each of the growing spaces from the irradiation amount measuring unit at predetermined time intervals, and controls the moving mechanism based on the difference in the irradiation amounts among the plurality of growing spaces to replace a growing space with a relatively small difference with another growing space with a relatively large difference.

[0007] Furthermore, the above-mentioned plant growing device may include a plurality of growing spaces arranged adjacent to each other, each growing space being configured to grow a portion of at least one plant above the roots, the artificial light source being shared by the plurality of growing spaces, a movement mechanism that moves the artificial light source relatively to the plurality of growing spaces, and a movement control unit that controls the movement mechanism, wherein the irradiance measurement unit measures the irradiance of the plant grown in each of the growing spaces, and when the irradiance measured by the irradiance measurement unit is less than the irradiance required for growing the plant, the movement control unit controls the movement mechanism so that the artificial light source moves relatively to an irradiation position of the artificial light source for a growing space that grows a plant with less irradiance than the measured irradiance.

[0008] Furthermore, the above-mentioned plant growing device may include a plurality of housings, each defining a closed growing space in which at least one plant above its roots is grown, the artificial light source being shared by the plurality of housings, a movement mechanism for moving each of the housings relative to the artificial light source, and a movement control unit for controlling the movement mechanism, wherein the irradiance measurement unit measures the irradiance of a plant grown in each of the growing spaces, and when the irradiance measured by the irradiance measurement unit is less than the irradiance required for growing the plant, the movement control unit controls the movement mechanism to move the housing having the growing space in which the plant is grown with less irradiance to a position irradiated by the artificial light source.

[0009] Furthermore, in the above-described plant growing device, the control mechanism may have a first filter that removes the ultraviolet wavelength component from the sunlight and a second filter that removes the infrared wavelength component, and be configured to be able to switch between irradiating the plant with at least sunlight filtered through the first and second filters and sunlight filtered only through the first filter, and may also include a growth space for growing at least one portion of the plant above its roots, a temperature sensor that measures the temperature of the growth space, and a sunlight irradiation control unit that controls the control mechanism to irradiate the plant with sunlight filtered only through the first filter when the temperature measured by the temperature sensor is equal to or higher than a predetermined temperature.

[0010] On the other hand, one aspect of the plant cultivation method according to the present invention is a plant cultivation method for cultivating a plant using artificial light, and includes a sunlight guiding step of guiding sunlight to the plant, and a control step of controlling the wavelength components of the sunlight so as to remove specific wavelength components from the sunlight before it is irradiated onto the plant.

[0011] The present invention can prevent plants from being harmed by light of specific wavelength components contained in sunlight.

[0012] 17 is a front cross-sectional view showing an example of the schematic configuration of a plant growing device according to the first embodiment. FIG. 18 is a diagram showing an example of a sunlight irradiation state of the plant growing device according to the first embodiment. FIG. 19 is a front cross-sectional view of the light source panel of the plant growing device of FIG. 1. FIG. 20 is a longitudinal cross-sectional view of the light source panel of FIG. 2. FIG. 21 is a longitudinal cross-sectional view of a light source panel according to a modified example. FIG. 22 is a flowchart showing a sunlight irradiation process according to the first embodiment. FIG. 23 is a plan cross-sectional view of the plant growing device of FIG. 1. FIG. 24 is a flowchart showing an artificial light irradiation process according to the first embodiment. FIG. 25 is a plan cross-sectional view of the plant growing device of FIG. 7 in which the pair of light source panels have been moved. FIG. 26 is a plan cross-sectional view of the plant growing device of FIG. 7 in which the pair of light source panels have been moved to other positions. FIG. 27 is a plan cross-sectional view of a plant growing device according to a second embodiment. FIG. 28 is a plan cross-sectional view of the plant growing device of FIG. 11 in which the plurality of growth spaces have been moved. FIG. 29 is a plan cross-sectional view of the plant growing device of FIG. 11 in which the plurality of growth spaces have been moved to other positions. FIG. 29 is a plan cross-sectional view of a plant growing device according to a third embodiment. FIG. 29 is a plan cross-sectional view of the plant growing device of FIG. 14 in which the pair of light source panels have been moved. FIG. 21 is a plan cross-sectional view of the plant growing device of FIG. 14 in which the pair of light source panels have been moved to other positions. FIG. 29 is a front cross-sectional view showing an example of the schematic configuration of a plant growing device according to a fourth embodiment. FIG. 29 is a plan cross-sectional view of the plant growing device of FIG. 17. 22(a) and 22(b) are diagrams schematically illustrating the operation of exchanging the positions of a plurality of cultivation devices. FIG. 22(a) is a front cross-sectional view showing a schematic configuration example of a plant cultivation device according to a fifth embodiment. FIG. 22(b) is a side cross-sectional view of a plant cultivation device according to a fifth embodiment. FIG. 22(c) is a side cross-sectional view of the plant cultivation device of FIG. 21 in which the light source panel has been moved to another position.

[0013] Various embodiments for carrying out the present invention will be described in detail below with reference to the accompanying drawings. Note that the embodiments described below are examples of means for realizing the present invention, and should be appropriately modified or changed depending on the configuration of the device to which the present invention is applied and various conditions, and the present invention is not limited to the following embodiments.

[0014] In addition, in the following description of the drawings, the same or similar parts are designated by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the vertical and horizontal dimensions and scales of the components or parts may differ from those of the actual parts. Therefore, the specific dimensions and scales should be determined by taking into consideration the following explanation. Furthermore, it goes without saying that the drawings may include parts whose dimensional relationships and ratios differ from one another.

[0015] [First Embodiment] [Configuration] A first embodiment of the present invention will be described below with reference to the accompanying drawings. FIGS. 1 to 10 are diagrams illustrating the first embodiment. FIG. 1 is a front cross-sectional view showing a schematic configuration example of a plant growing device 1 according to the first embodiment. As shown in FIG. 1, the plant growing device 1 according to the first embodiment includes a cultivation device 2 for growing multiple plants. The plant growing device 1 is installed in a building 50 that constitutes a plant factory. The plants 3 grown in the plant growing device 1 are, for example, agricultural crops such as beans, but may also be other plants that perform photosynthesis. The plant growing device 1 according to the first embodiment is preferably used for plants that grow long stems and have many leaves that overlap vertically as they grow. The multiple plants 3 are arranged in a direction perpendicular to the plane of FIG. 1 (see FIGS. 8 to 10). The cultivation device 2 includes an upper portion 2A and a lower portion 2B disposed below the upper portion 2A. A lower housing 2C is provided in the lower portion 2B. The lower housing 2C has a peripheral wall and a bottom wall that define a lower space 2D, and its top is open. At least one liquid fertilizer tank 4 is disposed inside the lower housing 2C. When multiple liquid fertilizer tanks 4 are provided, they are arranged in a direction perpendicular to the plane of FIG. 1 (see liquid fertilizer tanks 4A and 4B in FIG. 17). The roots of plants 3 (including the main root and lateral roots) are disposed inside the liquid fertilizer tank 4, where the roots grow. The liquid fertilizer tank 4 is a container that contains a nutrient solution 41 (also called liquid fertilizer or liquid fertilizer) containing fertilizer to be applied to the roots of the plants 3. A plant support panel 5 is attached to the top of the liquid fertilizer tank 4. The trunks of multiple plants 3 penetrate 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 have numerous through-holes. The plant cultivation device 1 further includes a nutrient solution supply system 10. A nutrient solution supply system 10 is connected to the liquid fertilizer tank 4 via a liquid fertilizer pipeline 11 , and the nutrient solution supply system 10 supplies nutrient solution 41 to the liquid fertilizer tank 4 .

[0016] Two growing spaces 6A and 6B are arranged in the upper portion 2A. The growing spaces 6A and 6B are spaces above the liquid fertilizer tank 4. The growing spaces 6A and 6B are arranged adjacent to each other in a direction perpendicular to the plane of FIG. 1 (see FIGS. 5 and 6). In each of the growing spaces 6A and 6B, the portion above the roots of at least one plant 3 (i.e., the stems and leaves) grows (is cultivated). In the first embodiment, the portions above the roots of multiple plants 3 (portions above the liquid fertilizer tank 4) grow in each of the growing spaces 6A and 6B. Hereinafter, the portions above the roots of the plants 3 are referred to as "above-tank portions." In addition, a pair of light source units 7 are arranged in the upper portion 2A. The growing spaces 6A and 6B are interposed between these light source units 7. In other words, each light source unit 7 is arranged near the growing spaces 6A and 6B. Each light source unit 7 has a light source panel (artificial light source) 7a and a transparent heat-shielding case (heat-shielding partition) 7b surrounding the light source panel 7a. The pair of light source panels 7a are oriented vertically and arranged parallel to each other, facing each other. The pair of heat-shielding cases 7b surrounding the light source panels 7a are also oriented vertically and arranged parallel to each other.

[0017] Each light source panel 7a emits artificial light L for growing the plants 3. The light source units 7 are arranged on both sides of the growing spaces 6A, 6B, and the light source panels 7a supply the artificial light L from the sides to the plants 3 in the growing spaces 6A, 6B. Therefore, the artificial light L can be applied as evenly as possible to both the upper and lower leaves of the plants 3 in the growing stage, where the stems are long and many leaves overlap vertically. In the first embodiment, a pair of light source units 7 are arranged on both sides of the growing spaces 6A, 6B, but one light source unit 7 may be arranged on one side of the growing spaces 6A, 6B. The pair of light source panels 7a are shared by multiple growing spaces 6A, 6B and supply the artificial light L to the growing spaces 6A, 6B. Each heat-shielding case 7b is formed from a light-transmitting material, such as glass or a transparent resin. Examples of usable transparent resins include, but are not limited to, acrylic, polyethylene terephthalate, polycarbonate, and polyvinyl chloride. Each heat-shielding case 7b has a wall 7c interposed between the growing spaces 6A, 6B and the light source panel 7a. The wall 7c is formed flat, and the walls 7c of a pair of heat-shielding cases 7b are arranged parallel to each other. Each heat-shielding case 7b suppresses or inhibits heat radiation and heat conduction from the light source panel 7a, which is a heat source, to prevent overheating of the growing spaces 6A, 6B.

[0018] In the first embodiment, each heat-shielding case 7b entirely surrounds the light source panel 7a. However, the heat-shielding case 7b does not necessarily have to entirely surround the light source panel 7a. For example, the upper and lower walls of the heat-shielding case 7b may be omitted, or the outer wall opposite the wall 7c may be omitted. Furthermore, the heat-shielding case 7b does not have to be transparent except for the wall 7c, which is interposed between the light source panel 7a and the growing spaces 6A and 6B and allows artificial light L to enter the growing spaces 6A and 6B. To prevent overheating of each heat-shielding case 7b and the light source panels 7a therein, a blower (not shown) may be used to generate airflow inside the heat-shielding case 7b, thereby cooling the heat-shielding case 7b with air.

[0019] Instead of or in addition to the air blower, a refrigerant pipe or refrigerant chamber (not shown) for lowering the temperature of each heat-shielding case 7b may be arranged near each heat-shielding case 7b (e.g., in contact with each heat-shielding case 7b). The refrigerant may be a gas such as air or a hydrofluorocarbon, or a liquid such as water or ammonia. The refrigerant pipe or refrigerant chamber is preferably located on the side opposite the wall 7c of each heat-shielding case 7b. Fins may be provided on the wall opposite the wall 7c of each heat-shielding case 7b to enhance cooling efficiency. The interior of each heat-shielding case 7b may be evacuated to efficiently suppress heat conduction from the light source panel 7a. In this case, the refrigerant pipe or refrigerant chamber and / or fins are preferably provided. The distance Z between a pair of light source units 7 (i.e., the distance between the walls 7c of a pair of heat-shielding cases 7b) is set to a size that allows artificial light L to be applied evenly and sufficiently to each leaf of a plant 3 that has grown to a certain extent.

[0020] However, it is preferable that the spacing Z between the light source units 7 be set so as to restrict excessive lateral growth of the plants 3. That is, it is preferable that the heat-shielding case 7b be positioned relative to the plants 3 (disposed relative to the growth spaces 6A and 6B) so as to restrict lateral growth of the leaves of the plants 3 cultivated within the growth spaces 6A and 6B. Specifically, it is preferable that the horizontal distance from the base of the plants 3 to the heat-shielding case 7b be set shorter than the maximum horizontal distance from the base of the plants 3 that the tips of the leaves at their maximum growth are expected to reach if the heat-shielding case 7b were not present. In this case, the heat-shielding case 7b restricts excessive leaf growth of the plants 3, allowing the plants 3 to be grown in a small space (small width). The plant growing device 1 further includes a sunlight guide mechanism, a control mechanism 8, an air-conditioning system 12, a light-emitting control device 18, an irradiance measurement device 19, an environmental control device 20, and a movement control device 30. FIG. 2 is a diagram showing an example of the state of sunlight irradiation of the plant growing device 1 according to the first embodiment.

[0021] 1 and 2 , the side walls 52 and ceiling wall 54 of the building 50 housing the plant growing device 1 are substantially entirely made of sunlight entrance windows (not shown) made of a light-transmitting material, allowing sunlight SL to enter the building 50. The light-transmitting material is formed, for example, from glass or a transparent resin. Usable transparent resins include, but are not limited to, acrylic, polyethylene terephthalate, polycarbonate, and polyvinyl chloride. In other words, the sunlight entrance windows in the side walls 52 and ceiling wall 54 are configured to guide sunlight SL to the plants 3 inside the building, and the side walls 52 and ceiling wall 54 form a sunlight guide mechanism.

[0022] In addition, when the building 50 is cubic, substantially the entire surfaces of the four side walls 52 may be configured with sunlight entrance windows, but this configuration is not limited thereto. For example, substantially the entire surfaces of some of the four side walls 52, such as two opposing side walls 52, onto which sunlight SL is desired to be incident may be configured with sunlight entrance windows. Furthermore, if sunlight SL incident through the side walls 52 is sufficient, the ceiling wall 54 does not need to be configured with sunlight entrance windows on substantially the entire surface. Meanwhile, a control mechanism 8 that controls the wavelength components of sunlight SL to remove specific wavelength components from sunlight SL is provided on the inside of the side walls 52 and ceiling wall 54 of the building 50. The control mechanism 8 includes filter units 8a and 8b that include removal filters that remove ultraviolet and infrared wavelength components from sunlight SL incident through the sunlight entrance windows that form the ceiling wall 54 and side walls 52, and light-blocking filters that block the incidence of sunlight SL.

[0023] That is, the control mechanism 8 allows sunlight SL', from which ultraviolet and infrared wavelength components have been removed by the removal filter, to be irradiated onto the plants 3 from sunlight SL incident through the sunlight entrance windows in the side walls 52 and the ceiling wall 54. This makes it possible to remove ultraviolet wavelength components that are harmful to the cells of the plants 3 and to prevent temperature increases due to infrared rays. Furthermore, the light-shielding filter can block sunlight SL' from being irradiated onto the plants 3 outside of the required irradiation time.

[0024] The filter units 8a and 8b are configured so that at least the removal filter can be switched and applied to the inside of the incident surface of the sunlight entrance window. For example, a retractable removal filter can be unrolled and applied to the incident surface by an electric roller device or the like. The light-shielding filter can also be configured in a similar manner.

[0025] The light-shielding filter may be, for example, a filter that is permanently attached to the sunlight entrance window, that is black when not energized and exhibits light-shielding performance, and that is transparent when energized and exhibits light transmission. In this case, the elimination filter may be, for example, a film-like, permanently attached type or a thin, fixed type. Furthermore, if sunlight SL' can continue to be irradiated during the day, only the elimination filter is required, and the light-shielding filter can be eliminated. In the following first embodiment, a light-shielding filter that can be switched by energizing is used, and a permanently attached type elimination filter is also used.

[0026] The air conditioning system 12 adjusts the environment of the cultivation device 2 in which the plants are grown to a temperature, humidity, and carbon dioxide (CO ) suitable for plant growth. ２ The air conditioning system 12 is connected to the lower housing 2C via an air pipe 14 and communicates with the lower space 2D inside the lower housing 2C. The air conditioning system 12 also communicates with the growing spaces 6A and 6B via an air pipe 16.

[0027] The air conditioning system 12 supplies conditioned air to the cultivation apparatus 2 through the air duct 14 or 16 and takes in air from the interior of the cultivation apparatus 2 through the air duct 16 or 14. There are multiple ventilation gaps 40 between the lower housing 2C of the lower part 2B of the cultivation apparatus 2 and the liquid fertilizer tank 4, and the air conditioned by the air conditioning system 12 can flow through the ventilation gaps 40 from the upper part 2A (growth spaces 6A, 6B) of the cultivation apparatus 2 to the lower part 2B (lower space 2D) or from the lower part 2B to the upper part 2A. The light emission control device 18 controls the light emission of the light source panel 7a of the light source unit 7 in response to a command from the environmental control device 20. For example, the light emission control device 18 turns the light source panel 7a on and off. The irradiance measuring device 19 includes an illuminance sensor 19a capable of detecting the illuminance of sunlight, a rod-shaped support portion 19b that supports the illuminance sensor 19a, and an irradiance calculation portion 19c that calculates the irradiance of sunlight SL' on the plant 3 based on the illuminance detected by the illuminance sensor 19a. While one illuminance sensor 19a is provided for each of the growth spaces 6A and 6B (see FIGS. 1 and 7, etc.), this configuration is not limiting and multiple illuminance sensors 19a may be provided for each growth space. For example, one sensor may be provided for each plant 3. Furthermore, while a sensor that detects the illuminance of sunlight is used as the illuminance sensor 19a, this configuration is not limiting and a sensor that detects the photon flux density of light with a wavelength effective for photosynthesis (400 nm to 700 nm) may also be used.

[0028] The irradiance calculation unit 19c includes a processor, a timer for measuring time, and a read-only memory (ROM) for storing control programs, setting data, and the like, all of which are not shown. It also includes a random access memory (RAM) for storing data read from the ROM and calculation results required for the processor's calculation process, and an interface (I / F) for data input and output to and from external devices. These components are interconnected via a bus, which is a signal line for transferring data, allowing data exchange between them. In response to a command from the environmental control device 20, the irradiance calculation unit 19c calculates the irradiance of sunlight SL′, with an illuminance equal to or greater than the illuminance required for photosynthesis during the set irradiation time, on the plants 3 in the growth spaces 6A and 6B. The calculated irradiance is then output to the environmental control device 20. The environmental control device 20 includes a processor, a timer, a ROM, a RAM, and an I / F, all of which are interconnected via a bus, which is a signal line for transferring data, allowing data exchange between them. The environmental control device 20 is electrically connected to the nutrient solution supply system 10, the air conditioning system 12, the light emission control device 18, the irradiation amount calculation unit 19c, and the movement control device 30 via an I / F, and controls the operations of these devices.

[0029] As described below, the environmental control device 20 issues commands to the nutrient solution supply system 10 and the air conditioning system 12 to control the growth environment of the plants 3 in the growth spaces 6A and 6B. Additionally, the environmental control device 20 issues commands to the control mechanism 8 to control the irradiation and blocking of sunlight SL′ onto the plants 3 in the growth spaces 6A and 6B. Furthermore, the environmental control device 20 controls the operation of the movement control device 30 and the light-emitting control device 18 based on the irradiation amount from the irradiation amount calculation unit 19c, and controls the irradiation of artificial light L into the growth spaces where the irradiation amount is insufficient with sunlight alone. That is, in the first embodiment, if irradiation with sunlight SL′ alone can irradiate light with an amount of light sufficient for photosynthesis, the light source unit 7 does not irradiate artificial light L. However, if irradiation with the amount of light required for photosynthesis is not irradiated, the deficiency is compensated for by irradiating artificial light L. Although not shown, the light source unit 7 is provided with a position sensor that detects the position of the light source panel 7a, and the environmental control device 20 is able to determine the position of the light source panel 7a from the detection result of the position sensor.

[0030] The movement control device 30 controls a movement mechanism (not shown) to move the light source panel 7a relative to the growth spaces 6A and 6B in response to a command from the environmental control device 20. That is, the cultivation device 2 has a movement mechanism that moves the light source panel 7a relative to the growth spaces 6A and 6B. The movement mechanism may be, for example, a motor-driven wheel, a belt conveyor mechanism, a track mechanism, or a rack-and-pinion mechanism. FIG. 3 is a front view of the light source panel of the plant cultivation device of FIG. 1 , and FIG. 4 is a longitudinal cross-sectional view of the light source panel of FIG. 3 . Also, FIG. 5 is a longitudinal cross-sectional view of a light source panel according to a modified example. As shown in FIG. 3 , the light source panel 7a 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 substantially evenly and sufficiently to multiple plants 3 planted at intervals from one another.

[0031] The light source of the light source panel 7a 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.

[0032] 3 and 4, the light source panel 7a has a flat substrate 32 serving as a support, and a plurality 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 arranged regularly (specifically, in a matrix) at equal intervals both vertically and horizontally.

[0033] However, LED chips 33 that emit red wavelength light more strongly than light of other wavelengths and LED chips 33 that emit blue wavelength light more strongly than light of other wavelengths may be arranged on substrate 32. In addition, LED chips 33 that emit green wavelength light more strongly than light of other wavelengths may be arranged on substrate 32. LED chips 33 are mounted in a light-emitting region of light source panel 7a, which has a height X1 and a width Y1.

[0034] The substrate 32 is provided with wiring (not shown) for lighting these LED chips 33. A light-emitting control device 18 (see FIG. 1) for controlling the light emission of these LED chips 33 is provided outside the light source panel 7a, and the wiring is electrically connected to the light-emitting control device 18.

[0035] To increase the efficiency of utilizing the artificial light L within the cultivation spaces 6A and 6B, the surface of the substrate 32 facing the LED chips 33 preferably has high light reflectivity. The substrate 32 is preferably formed from a light-reflecting material (e.g., a metal with a smooth surface). The surface of the substrate 32 facing the LED chips 33 may be coated with a light-reflecting paint. The light source panel 7a shown in Figures 3 and 4 is merely an example. The size, number, and spacing of the LED chips 33 are not limited to those shown. In the first embodiment, the substrate 32 of the light source panel 7a is a flat plate, but as shown in Figure 5, the substrate 32 may also be a corrugated plate. In the first embodiment, the light source panel 7a includes multiple LED chips 33 that generate little heat. However, the artificial light source may also be at least one fluorescent lamp, at least one cold-cathode fluorescent tube, or other light source.

[0036] [Sunlight Irradiation Control Process] Next, the sunlight irradiation control process executed by the environmental control device 20 will be described. Fig. 6 is a flowchart showing the sunlight irradiation control process according to the first embodiment. The processor of the environmental control device 20 starts a control program stored in a predetermined area of ​​the ROM, and executes the sunlight irradiation control process shown in the flowchart of Fig. 6 in accordance with the program. When the sunlight irradiation control process is executed by the processor, as shown in Fig. 6, the process first proceeds to step S100.

[0037] In step S100, it is determined whether or not it is time to start irradiating sunlight. If it is determined that it is time to start irradiating sunlight (Yes), the process proceeds to step S102. If it is determined that it is not time to start irradiating sunlight (No), the process repeats the determination process until it is time to start irradiating sunlight.

[0038] Here, the irradiation start timing of sunlight SL' occurs during the daytime when the sun is up, and this timing changes depending on the season. That is, in Japan, for example, the time of sunrise, the time of sunset, and the irradiation intensity change depending on the season (spring, summer, autumn, winter), so an appropriate timing is set in accordance with these. For example, the start time of a period when the daytime illuminance is relatively high is set as the irradiation start timing. When proceeding to step S102, a command is given to the control mechanism 8 to control the operation of the filter units 8a and 8b, and sunlight SL' that has passed through the removal filter is irradiated onto the cultivation spaces 6A, 6B. Then, proceeding to step S104.

[0039] That is, by passing electricity through the light-shielding filters of the filter sections 8a and 8b to make them transparent, sunlight SL can pass through the sunlight entrance window and the removal filter. As a result, for example, on a sunny day, sunlight SL' is irradiated onto the cultivation spaces 6A and 6B from above and diagonally to the side through the removal filter (see FIG. 2). FIG. 7 is a plan cross-sectional view of the plant cultivation device of FIG. 1. As shown in FIG. 7, the liquid fertilizer tank 4 is a long container, and multiple plants 3 are lined up along the longitudinal direction of the liquid fertilizer tank 4. The light source unit 7 and cultivation spaces 6A and 6B extend along the longitudinal direction of the liquid fertilizer tank 4.

[0040] 7, in the first embodiment, the heat shielding case 7b of each light source unit 7 has a length equal to or greater than the combined length of the growing spaces 6A, 6B. Therefore, in the first embodiment, the growing spaces 6A, 6B are spaces disposed above the single liquid fertilizer tank 4 and the single lower housing 2C, and are spaces interposed between the pair of light source units 7.

[0041] A light-shielding wall 9 is interposed between the growing spaces 6A and 6B. In other words, the light-shielding wall 9 divides the growing spaces 6A and 6B. In the first embodiment, a pair of heat-shielding cases 7b and the light-shielding wall 9 define the growing spaces 6A and 6B. To increase the efficiency of use of artificial light L within the growing spaces 6A and 6B, both surfaces of the light-shielding wall 9 preferably have high light reflectivity. The light-shielding wall 9 is preferably formed from a light-reflecting material (e.g., a metal with smooth surfaces). Both surfaces of the light-shielding wall 9 may be coated with a light-reflective paint. In the first embodiment, the lower housing 2C, the liquid fertilizer tank 4, and the heat-shielding case 7b are fixed. The growing spaces 6A and 6B above the liquid fertilizer tank 4 are stationary (i.e., fixed) in a fixed position. As described above, the movement control device 30 controls a movement mechanism (not shown) to move the light source panel 7a relative to the growing spaces 6A and 6B in response to a command from the environmental control device 20.

[0042] The movement control device 30 reciprocates the light source panels 7a of each light source unit 7 along the longitudinal direction of the liquid fertilizer tank 4 (the longitudinal direction of the cultivation spaces 6A, 6B). In other words, the movement control device 30 moves the light source panels 7a inside the heat-shielding case 7b while keeping the heat-shielding case 7b stationary relative to the cultivation spaces 6A, 6B. The movement control device 30 synchronously moves the light source panels 7a of the pair of light source units 7. Furthermore, the heat-shielding case 7b of the first embodiment is provided with an evacuation area 7d for retracting the pair of light source panels 7a to a position that does not face either of the cultivation spaces 6A, 6B so that the pair of light source panels 7a do not interfere with the irradiation of sunlight SL' onto the cultivation spaces 6A, 6B.

[0043] That is, when sunlight SL' is irradiated onto the growth spaces 6A and 6B, the light source panel 7a is retracted to the evacuation area 7d in advance, as shown in FIG. 7 . In the first embodiment, the light source panel 7a is always retracted before the start time of the sunlight SL' irradiation period. Specifically, a position sensor (not shown) detects the position of the light source panel 7a. If the light source panel 7a is not in the evacuation area 7d, the movement control device 30 controls the light source panel 7a to move to the evacuation area 7d in advance. As a result, sunlight SL' is irradiated onto the growth spaces 6A and 6B, as shown in FIG. 7 . Returning to FIG. 6 , in step S104, the irradiation amount calculation unit 19c issues a command to measure the irradiation amount of sunlight SL' irradiated onto each growth space. Then, the process proceeds to step S106. Based on the detection result of the illuminance sensor 19a, the irradiation amount calculation unit 19c uses a timer to measure the irradiation time of sunlight SL' at an illuminance equal to or greater than the illuminance required for photosynthesis. Then, the process proceeds to step S106.

[0044] Here, the irradiation amount calculation unit 19c is configured to measure the irradiation time of sunlight SL' at an illuminance equal to or greater than the illuminance required for photosynthesis, calculate the irradiation amount from the measured irradiation time and illuminance, sequentially integrate the calculated irradiation amounts, and store them in RAM. For example, in a case where the weather is sunny with occasional clouds and there are multiple time periods with sufficient illuminance and multiple time periods with insufficient illuminance, the irradiation amount during the time periods with sufficient illuminance is integrated. In step S106, it is determined whether the irradiation end time of sunlight SL' has arrived, and if it is determined that the end time has arrived (Yes), the process proceeds to step S108. On the other hand, if it is determined that the end time has not arrived (No), the process proceeds to step S104.

[0045] Here, when the environmental control device 20 determines that the end time has arrived, it issues a command to the control mechanism 8 to turn off the power to the light-blocking filters of the filter units 8 a and 8 b, blocking sunlight SL from passing through the sunlight entrance window and the removal filter. At this time, by turning off all the electric lights in the building 50, it is possible to create a state in which no light is irradiated on the plants 3 (night state).

[0046] Since a nighttime environment may be necessary for growing the plants 3, depending on the type of plant 3 being grown, it may be necessary to provide a nighttime period during which neither sunlight SL' nor artificial light L (including other lighting) is irradiated. In the first embodiment, the nighttime period is defined as a period during which sunlight SL' is not irradiated and supplementary irradiation by artificial light L is not performed. If the process proceeds to step S108, the accumulated result of the irradiation amount of sunlight SL' with the illuminance required for photosynthesis for each growth space (hereinafter referred to as "total irradiation amount") is obtained from the irradiation amount calculation unit 19c, and the process proceeds to step S110.

[0047] In step S110, it is determined whether the total irradiation amount obtained in step S108 is less than the predetermined irradiation amount required for photosynthesis in one day (hereinafter referred to as the "first required irradiation amount"). If it is determined that there is any growth space where the irradiation amount is less than the first required irradiation amount (Yes), the process proceeds to step S112, and if it is determined that there is not (No), the process ends. If the process proceeds to step S112, the process executes an irradiation amount supplementary control process for the growth space determined to be less than the first required irradiation amount, and the process ends.

[0048] Here, the irradiation amount complementary control process is a process of controlling the light-emission control device 18 and the movement control device 30 to complement (make up) the shortage of the irradiation amount from sunlight SL' relative to the first required irradiation amount when the weather is rainy or cloudy, for example, by irradiating artificial light L from the light source unit 7. Specifically, this process controls the light emission of the light source panel 7a so that the total irradiation amount by irradiating the plants 3 with artificial light L from the light source panel 7a reaches the first required irradiation amount. [Irradiation Amount Complementary Control Process] Next, the irradiation amount complementary control process executed by the environmental control device 20 will be described.

[0049] FIG. 8 is a flowchart showing the irradiation amount supplement control process according to the first embodiment, and FIG. 9 is a plan cross-sectional view of the plant growing device of FIG. 7 in which the pair of light source panels has been moved. Also, FIG. 10 is a plan cross-sectional view of the plant growing device of FIG. 7 in which the pair of light source panels has been moved to another position. When the irradiation amount supplement control process is executed in step S112, as shown in FIG. 8 , the process first proceeds to step S200. In step S200, the irradiation time of artificial light L required to supplement the shortage (hereinafter referred to as "artificial light irradiation time") is calculated, and the process proceeds to step S202. In step S202, a command is issued to the movement control device 30 to move the pair of light source panels 7a to the irradiation position of the artificial light L in the growth space to be supplemented. Then, the process proceeds to step S204.

[0050] As a result, the movement control device 30 controls the movement mechanism, and the pair of light source panels 7a move to positions where they can irradiate the target cultivation space with artificial light L. For example, when the target cultivation space 6A is the cultivation space to be complemented, as shown in Fig. 9, the pair of light source panels 7a move from the retreat area 7d shown in Fig. 7 to a position where the artificial light L is irradiated onto the cultivation space 6A.

[0051] 8, in step S204, a command is given to the light source unit 7 to irradiate the growth space to be complemented with artificial light L, and measurement of the irradiation time is started using a timer, and the process proceeds to step S206. As a result, artificial light L with a photon flux density effective for photosynthesis is irradiated from the pair of light source panels 7a onto the growth space to be complemented, and the irradiation time is measured.

[0052] The example in Fig. 9 shows a state in which a pair of light source panels 7a are positioned on the cultivation space 6A side and irradiate artificial light L onto the plants 3 in the cultivation space 6A. In this state, the artificial light L is not irradiated onto the plants 3 in the cultivation space 6B. The light-shielding wall 9 blocks the artificial light L from traveling from the cultivation space 6A to the cultivation space 6B. Therefore, a state in which the plants in the cultivation space 6A are irradiated with the artificial light L output from the light source panels 7a and a state in which the plants in the cultivation space 6B are not irradiated with the artificial light L output from the light source panels 7a are simultaneously created.

[0053] Returning to FIG. 8 , in step S206, it is determined whether or not the artificial light irradiation time has elapsed based on the time measured by the timer. If it is determined that the artificial light irradiation time has elapsed (Yes), the process proceeds to step S208. If it is determined that the artificial light irradiation time has not elapsed (No), the determination process is repeated until the artificial light irradiation time has elapsed.

[0054] If the process proceeds to step S208, it is determined whether the complementation process using artificial light L has been completed for all complementation targets. If it is determined that the complementation process has been completed (Yes), the process ends and returns to the original process. If it is determined that the complementation process has not been completed (No), the process proceeds to step S202.

[0055] For example, if the irradiation amount needs to be supplemented for the cultivation space 6B as well, it is determined that the irradiation process of the artificial light L has not been completed for all of the targets to be supplemented. In this case, the movement control device 30 controls the movement mechanism, and as shown in Fig. 10, the pair of light source panels 7a move from the irradiation positions shown in Fig. 9 to irradiation positions near the cultivation space 6B.

[0056] 10 shows a state in which a pair of light source panels 7a are positioned on the cultivation space 6B side and irradiate the plants 3 in the cultivation space 6B with artificial light L. Therefore, a state in which the plants 3 in the cultivation space 6B are irradiated with the artificial light L output from the light source panels 7a and a state in which the plants 3 in the cultivation space 6A are not irradiated with the artificial light L output from the light source panels 7a are simultaneously created.

[0057] In the first embodiment, a time period for irradiating sunlight SL' is set during the day, and the insufficiency of the amount of sunlight SL' irradiated in this set time period to meet the first required irradiation amount is compensated for by irradiating artificial light L from the light source unit 7, but the present invention is not limited to this configuration. For example, if it is known in advance from rain cloud radar or the like that the weather conditions will make it difficult to irradiate sunlight SL' in the set time period, irradiation of sunlight SL' on that day may be stopped and switched to irradiation with only artificial light L from the light source unit 7.

[0058] In this case, the movement control device 30 controls the movement mechanism to move the light source panel 7a from the vicinity of one of the growing spaces 6A, 6B to the vicinity of the other in a 12-hour cycle, for example. This makes it possible to create daytime and nighttime conditions in the growing spaces 6A, 6B in a 12-hour cycle. That is, in each of the growing spaces 6A, 6B, 12 hours of the day are daytime and the other 12 hours are nighttime.

[0059] The light source panel 7a may be moved from one of the growth spaces 6A, 6B to the other at other intervals, without being limited to this time cycle. For example, the light source panel 7a may be moved from one of the growth spaces 6A, 6B to the other at six-hour, four-hour, or three-hour intervals. In any case, in each of the growth spaces 6A, 6B, a total of 12 hours of daylight and 12 hours of nighttime are present. Furthermore, rather than being limited to 12 hours of daylight and 12 hours of nighttime, either one of the periods may be increased or decreased. Furthermore, other combinations may be used, such as 16 hours of daylight and 8 hours of nighttime, or 8 hours of daylight and 16 hours of nighttime, as long as they are favorable or do not pose a problem for the growth of the plants 3. In the first embodiment, the control mechanism 8 is configured to use a filter to remove ultraviolet and infrared wavelength components (invisible light components) from the sunlight SL. However, this configuration is not limited to this. For example, a configuration may be used to remove some wavelength components of visible light, such as red light and blue light. For example, red light contributes to plant growth, and blue light contributes to the color of plants, so by properly controlling their removal, it is possible to prevent harm such as overgrowth and deterioration of color caused by excessive exposure to these wavelength components.

[0060] According to the first embodiment, the control mechanism 8 can irradiate the cultivation spaces 6A, 6B with sunlight SL', which has been obtained by removing ultraviolet and infrared wavelength components from sunlight SL incident via the sunlight guiding mechanism. In addition, any deficiency in the amount of illumination obtained by irradiating sunlight SL' alone can be compensated for by irradiating artificial light L from the light source unit 7. This allows the plants 3 to be grown using a combination of sunlight and artificial light, thereby reducing the power consumption of the light source unit 7 and the electricity costs required for growing the plants 3.

[0061] Furthermore, since the plant 3 can be grown by irradiating it with sunlight SL' from which the ultraviolet and infrared wavelength components have been removed, it is possible to prevent harm to the plant 3 from ultraviolet and infrared rays. For example, if the plant 3 is a legume, ultraviolet irradiation may cause harm by excessive production of isoflavones. If the isoflavone content is too high, there is a risk of the plant 3 becoming tasteless. On the other hand, infrared irradiation may cause harm to the plant 3 by increasing the temperature of the cultivation spaces 6A and 6B that are the target of irradiation, which may cause heat damage to the plant 3.

[0062] In addition to removing infrared rays, the heat-shielding case 7b thermally isolates the growing spaces 6A, 6B from the light source panel 7a, making them less susceptible to the effects of heat. In other words, the heat-shielding case 7b prevents the growing spaces 6A, 6B from overheating. This reduces the energy required by the air-conditioning system 12 to control the air temperature in the growing spaces 6A, 6B, making it easier to maintain the growing spaces 6A, 6B in an environment suitable for the plants being grown.

[0063] Furthermore, by moving the light source panel 7a relative to the growing spaces 6A, 6B using the movement control device 30, the multiple growing spaces 6A, 6B can share the light source panel 7a and use the light source panel 7a in a time-division manner (i.e., at different periods). In other words, by sharing the light source panel 7a between the multiple growing spaces 6A, 6B, the number of light source panels 7a does not need to correspond to the number of growing spaces 6A, 6B. In the first embodiment, the light source units 7 are arranged on both sides of the two growing spaces 6A, 6B, but each light source unit 7 has a single light source panel 7a. It is not necessary for each light source unit 7 to have two light source panels 7a corresponding to the two growing spaces 6A, 6B. Therefore, an increase in the number of light source panels 7a can be prevented. This reduces the number of light source units 7 and reduces costs.

[0064] Second Embodiment [Configuration] Next, a second embodiment of the present invention will be described with reference to the drawings. FIGS. 11 to 13 are diagrams illustrating the second embodiment. The second embodiment differs from the first embodiment in that, when irradiating artificial light L, the growth spaces 6A and 6B are moved to the irradiation positions of a pair of fixed light source panels 7a. Below, differences from the first embodiment will be described in detail, and overlapping portions will be omitted as appropriate. FIG. 11 is a plan cross-sectional view of a plant growing device according to the second embodiment. FIG. 12 is a plan cross-sectional view of the plant growing device of FIG. 11 in which the plurality of growth spaces have been moved. FIG. 13 is a plan cross-sectional view of the plant growing device of FIG. 11 in which the plurality of growth spaces have been moved to other positions. As shown in FIG. 11 , the plant growing device 1A according to the second embodiment has a light source unit 7 fixed in a predetermined position, and the growth spaces 6A and 6B can be moved in a direction along the longitudinal direction of the light source unit 7 by a movement mechanism (not shown).

[0065] That is, the movement control device 30 of the second embodiment controls a movement mechanism (not shown) to move the growing spaces 6A, 6B relative to the light source panel 7a in response to a command from the environmental control device 20. That is, the cultivation device 2 has a movement mechanism that moves the growing spaces 6A, 6B relative to the light source panel 7a. Note that the movement mechanism that moves the pair of light source panels 7a may be included as is or may be removed. Therefore, in the second embodiment, as shown in FIG. 11 , when sunlight SL′ is irradiated onto the growing spaces 6A, 6B, the growing spaces 6A, 6B are moved to positions (retracted positions) where sunlight SL′ is not blocked by the light source unit 7.

[0066] If, for example, the amount of irradiation with sunlight SL' is insufficient for the cultivation space 6B after irradiation with sunlight SL' during the set time period, the cultivation spaces 6A, 6B are moved from the retracted positions shown in Fig. 11 so that the cultivation space 6B is positioned at a position where the artificial light L is irradiated from the pair of light source panels 7a, as shown in Fig. 12. This allows the state shown in Fig. 12 to be transitioned to in which the artificial light L is irradiated to the plants 3 in the cultivation space 6B.

[0067] Furthermore, for example, in the case where the amount of irradiation of the growth space 6A by sunlight SL' alone is insufficient, as shown in FIG. 13 , the growth spaces 6A, 6B are moved from the position shown in FIG. 12 so that the growth space 6A is positioned at the irradiation position of a pair of light source panels 7a. This allows the state shown in FIG. 13 to be transitioned to where artificial light L is irradiated to the plants 3 in the growth space 6A. In the second embodiment, the liquid fertilizer pipe 11 and the air pipes 14, 16 are preferably extendable and bendable. Furthermore, in the second embodiment, the heat-shielding case 7b has a length equal to or greater than the length of the movement range of the growth spaces 6A, 6B because it serves to suppress the growth of the plants 3. In the second embodiment, the growth spaces 6A, 6B can be moved, which makes it possible to reduce the number of light source units 7 shared by multiple growth spaces. Furthermore, in the second embodiment, the heat-shielding case 7b is positioned relative to the plants 3 so as to restrict the lateral growth of the leaves of the plants 3 cultivated in the growth spaces 6A, 6B. This allows the plants 3 to be grown in a small space (small width).

[0068] Third Embodiment Configuration A third embodiment of the present invention will now be described with reference to the drawings. FIGS. 14 to 16 are diagrams illustrating the third embodiment. The third embodiment differs from the first and second embodiments in that the light source panel 7a is moved together with the heat-shielding case 7b. Below, differences from the first and second embodiments will be described in detail, and overlapping portions will be omitted where appropriate. FIG. 14 is a plan cross-sectional view of a plant growing device according to the third embodiment, FIG. 15 is a plan cross-sectional view of the plant growing device of FIG. 14 in which a pair of light source panels has been moved, and FIG. 16 is a plan cross-sectional view of the plant growing device of FIG. 14 in which a pair of light source panels has been moved to another position.

[0069] As shown in Figure 14, the plant cultivation device 1B of the third embodiment is configured so that the movement control device 30 moves a pair of light source panels 7a and a pair of heat-shielding cases 7b together along the longitudinal direction of the fixed cultivation spaces 6A, 6B.

[0070] 7 and 11 of the first and second embodiments, and the light source panel 7a is fixed inside the heat-shielding case 7b. The movement control device 30 synchronously moves a pair of light source units 7, each including a light source panel 7a and a heat-shielding case 7b, in response to a command from the environmental control device 20. In the third embodiment, as shown in FIG. 14, when sunlight SL′ is irradiated onto the cultivation spaces 6A and 6B, the pair of light source units 7 are moved to positions (retracted positions) where irradiation of sunlight SL′ onto the cultivation spaces 6A and 6B is not obstructed.

[0071] If, for example, after irradiation with sunlight SL' during the set time period, the amount of irradiation with sunlight SL' alone is insufficient for the cultivation space 6A, as shown in Fig. 15, the pair of light source units 7 are moved from the retracted position shown in Fig. 14 so that the cultivation space 6A is positioned at a position where the artificial light L is irradiated by the pair of light source panels 7a. This allows the cultivation space 6A to transition to the state shown in Fig. 15, in which the artificial light L is irradiated onto the plants 3 in the cultivation space 6A. In this state, the artificial light L is not irradiated onto the plants 3 in the cultivation space 6B. In other words, the cultivation space 6A can be in a daytime state, and the cultivation space 6B can be in a nighttime state.

[0072] Furthermore, for example, in the case where irradiation of sunlight SL' alone is insufficient for the cultivation space 6B, as shown in FIG. 16 , the pair of light source units 7 are moved from the position shown in FIG. 15 so that the cultivation space 6B is positioned at a position irradiated with artificial light L from the pair of light source panels 7a. This allows the state shown in FIG. 16 to be transitioned to in which artificial light L is irradiated to the plants 3 in the cultivation space 6B. In this state, artificial light is not irradiated to the plants 3 in the cultivation space 6A. In other words, the cultivation space 6B can be in a daytime state, and the cultivation space 6A can be in a nighttime state. Although not shown, as in the second embodiment, the movement control device 30 may move the cultivation spaces 6A and 6B without moving the light source panels 7a and the heat-shielding case 7b.

[0073] In the third embodiment, the heat-shielding case 7b does not need to have a length equivalent to the total length of the plurality of growing spaces 6A, 6B. Therefore, the heat-shielding case 7b can be made smaller. Furthermore, since the heat-shielding case 7b and the light source panel 7a are moved together, if the heat-shielding case 7b has a configuration in which it surrounds the light source panel 7a, the structure of the movement mechanism can be simplified.

[0074] [Fourth Embodiment] [Configuration] Next, a fourth embodiment of the present invention will be described with reference to the drawings. FIGS. 17 to 19 are diagrams illustrating the fourth embodiment. The fourth embodiment differs from the first to third embodiments in that multiple growing spaces are each enclosed by a housing, allowing for independent control of the growing environment. Additionally, the fourth embodiment differs from the first to third embodiments in that movement control is performed to replace growing spaces located in positions with high illuminance with growing spaces located in positions with low illuminance during the irradiation period of sunlight SL'. Below, differences from the first to third embodiments will be described in detail, and overlapping portions will be omitted where appropriate. FIG. 17 is a front cross-sectional view showing a schematic configuration example of a plant growing device according to the fourth embodiment, and FIG. 18 is a plan cross-sectional view of the plant growing device of FIG. 17.

[0075] As shown in FIG. 17 , the plant growing device 1C of the fourth embodiment is configured such that the cultivation device 2 in the plant growing device 1 of the first embodiment is replaced with cultivation devices 2X and 2Y. The cultivation devices 2X and 2Y are arranged in a direction perpendicular to the plane of FIG. 17 (see FIG. 18 ). Each of the cultivation devices 2X and 2Y has an upper portion 2A' and a lower portion 2B' disposed below the upper portion 2A'. A liquid fertilizer tank 4A is disposed in the lower portion 2B' of the cultivation device 2X, and a liquid fertilizer tank 4B is disposed in the lower portion 2B' of the cultivation device 2Y. The cultivation devices 2X and 2Y further have a housing 13. The housing 13 extends vertically from the lower portion 2B' to the upper portion 2A' of each of the cultivation devices 2X and 2Y. A lower space 2D in which the liquid fertilizer tank 4A or 4B is disposed is provided below each housing 13. The liquid fertilizer tanks 4A and 4B are disposed inside the housings 13, respectively.

[0076] A growing space 6A is disposed in the upper portion 2A' of the cultivation device 2X, and a growing space 6B is disposed in the upper portion 2A' of the cultivation device 2Y. The growing spaces 6A and 6B are spaces above the liquid fertilizer tanks 4A and 4B, respectively, and are spaces inside the housing 13. The growing spaces 6A and 6B are arranged adjacent to each other in a direction perpendicular to the plane of the page in FIG. 17 (see FIG. 18). In the fourth embodiment, the above-tank portions of multiple plants 3 grow in each of the growing spaces 6A and 6B. However, the above-tank portion of only one plant 3 may grow in each of the growing spaces 6A and 6B. Each housing 13 defines a closed growing space 6A or 6B.

[0077] Furthermore, a pair of light source units (artificial light sources) 7 are disposed on the upper portion 2A' of the cultivation devices 2X and 2Y, with their lower portions supported by a pair of support members 7e. The cultivation spaces 6A and 6B can be interposed between these light source units 7. In other words, each light source unit 7 is positioned so as to be located near the cultivation spaces 6A and 6B. The pair of light source units 7 are oriented vertically, arranged parallel to each other, and facing each other. In the fourth embodiment, the pair of support members 7e form a movement path for the light source units 7, and the light source units 7 can be moved along the support members 7e to the vicinity of the cultivation space 6A or the vicinity of the cultivation space 6B by a movement mechanism (not shown). Furthermore, in the fourth embodiment, the cultivation devices 2X and 2Y are configured to be independently movable in a direction along the movement path of the light source units 7 on the support members 7e by a movement mechanism (not shown).

[0078] That is, the movement control device 30 of the fourth embodiment controls a movement mechanism (not shown) to move the cultivation devices 2X and 2Y independently in response to a command from the environmental control device 20. That is, the plant growing device 1C has a movement mechanism that moves the cultivation devices 2X and 2Y independently.

[0079] The housings 13 defining the growth spaces 6A and 6B are formed from a light-transmitting material, such as glass or a transparent resin. Examples of usable transparent resins include, but are not limited to, acrylic, polyethylene terephthalate, polycarbonate, and polyvinyl chloride. Each housing 13 has a wall 13a interposed between the growth space 6A or 6B and the light source unit 7. The wall 13a is flat, and the walls 13a of the pair of housings 13 are arranged parallel to each other. Each housing 13, together with the heat-shielding case 7b, suppresses or inhibits heat radiation and heat conduction from the light source panel 7a, which is a heat source, thereby preventing overheating of the growth spaces 6A and 6B.

[0080] In the fourth embodiment, each housing 13 surrounds the entire growing space 6A or 6B. However, each housing 13 does not necessarily have to surround the entire growing space 6A or 6B. For example, the upper and lower walls of each housing 13 may be omitted, or the upper and lower walls may not be transparent. The portion of each housing 13 that is present in the lower part 2B' and surrounds the liquid fertilizer tank 4A or 4B also does not have to be transparent. The distance between the pair of walls 13a of the housing 13 in Figure 17 is set to a size that allows artificial light L to be applied almost evenly and sufficiently to each leaf of a plant 3 that has grown to a certain extent.

[0081] However, it is preferable that the spacing between the walls 13a be set so as to restrict excessive lateral growth of the plants 3. In other words, it is preferable that the position of the walls 13a relative to the plants 3 be determined so as to restrict the lateral growth of the leaves of the plants 3 cultivated inside the cultivation spaces 6A, 6B. Specifically, it is preferable that the horizontal distance from the base of the plants 3 to the walls 13a be set shorter than the maximum horizontal distance from the base of the plants 3 that is predicted to be reached by the tips of the leaves at their maximum growth, assuming that the housing 13 is not present. In this case, the walls 13a restrict excessive leaf growth of the plants 3, allowing the plants 3 to be grown in a small space (small width).

[0082] The air conditioning system 12 adjusts the environment of the cultivation devices 2X and 2Y in which the plants are grown to a temperature, humidity, and carbon dioxide (CO ) suitable for plant growth. ２The air conditioning system 12 is connected to the housing 13 via an air pipe 14 and communicates with a lower space 2D inside the housing 13. The air conditioning system 12 is also connected to the housing 13 via an air pipe 16 and communicates with the growing spaces 6A and 6B inside the housing 13.

[0083] The air conditioning system 12 supplies conditioned air to the cultivation devices 2X, 2Y through the air pipes 14 or 16, and takes in air from the interior of the cultivation devices 2X, 2Y through the air pipes 16 or 14. In the lower part 2B' of the cultivation devices 2X, 2Y, there are a plurality of ventilation gaps 40 between the housing 13 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' (cultivation spaces 6A, 6B) of the cultivation devices 2X, 2Y to the lower part 2B' (lower space 2D) or from the lower part 2B' to the upper part 2A'.

[0084] The environmental control device 20 controls the internal environment of the cultivation devices 2X and 2Y. As described below, the environmental control device 20 issues commands to the nutrient solution supply system 10 and the air conditioning system 12 to independently control the cultivation spaces 6A and 6B to create environments that promote plant photosynthesis and environments that suppress photosynthesis. Specifically, during the daytime when photosynthesis is occurring, the environmental control device controls, for example, the irradiation of sunlight SL′, the irradiation of artificial light L as needed, the temperature, humidity, carbon dioxide concentration, and the concentration of liquid fertilizer. On the other hand, during the nighttime when photosynthesis is not occurring, the environmental control device controls, for example, only the temperature (e.g., adjusted to a lower temperature than during the daytime), without humidity control, or the supply or addition of carbon dioxide or liquid fertilizer. Figures 19(a) and 19(b) are schematic diagrams illustrating the operation of swapping the positions of multiple cultivation devices.

[0085] In the fourth embodiment, the environmental control device 20 acquires the integrated value of the irradiation amount of the illuminance required for photosynthesis of the sunlight SL′ in the cultivation devices 2X and 2Y from the irradiation amount calculation unit 19c every time a predetermined time elapses during the set irradiation period from the irradiation start time of the sunlight SL′ to the irradiation end time.

[0086] Then, when there is a cultivation device whose integrated value is equal to or greater than a predetermined threshold and a cultivation device whose integrated value is less than the first required irradiation amount, movement control is performed to swap their positions. Here, the predetermined threshold may be, for example, the first required irradiation amount or a value less than the first required irradiation amount. For example, it is set to a value that can be expected to provide irradiation of the sunlight SL' with more than the first required irradiation amount after the position swap. Specifically, as shown in FIG. 19(a), it is assumed that the illuminance of sunlight SL' on the housing 13 of the cultivation device 2X is weaker than the illuminance of sunlight SL' on the housing 13 of the cultivation device 2Y, and the irradiation amount on the housing 13 of the cultivation device 2X exceeds the predetermined threshold first.

[0087] In this case, the environmental control device 20 controls the movement control device 30 to move the cultivation device 2X to another position (a position with relatively weak illumination) as shown in Fig. 19(b), and move the cultivation device 2Y to the position with relatively strong illumination where the cultivation device 2X was previously located. According to the fourth embodiment, the cultivation devices in the positions where the illuminance of sunlight SL' is relatively strong can be swapped with the cultivation devices in the positions where the illuminance of sunlight SL' is relatively weak. This reduces the number of cultivation devices with insufficient illumination.

[0088] Furthermore, the housing 13, together with the heat-shielding case 7b, thermally isolates the growing spaces 6A, 6B from the light source panel 7a, making them less susceptible to the effects of heat. In other words, the heat-shielding case 7b and the housing 13 prevent the growing spaces 6A, 6B from overheating. This reduces the energy required by the air-conditioning system 12 to control the air temperature in the growing spaces 6A, 6B, making it easier to control the growing spaces 6A, 6B to an environment suitable for the plants being cultivated. Furthermore, because the housing 13 defines the growing spaces 6A, 6B as enclosed spaces, the environment can be individually controlled for each growing space, allowing for appropriate environmental control depending on, for example, the growing conditions of the plants 3. In the fourth embodiment, the housing 13 thermally isolates the growing spaces 6A, 6B from the light source panel 7a, so the heat-shielding case 7b may be omitted.

[0089] In the fourth embodiment, the positions of the growing spaces 6A and 6B are swapped when the irradiation amount of one of the growing spaces 6A and 6B first exceeds a predetermined threshold, but the present invention is not limited to this configuration. For example, when there are three or more growing spaces, the difference between the irradiation amount of each growing space and a predetermined threshold (e.g., a first required irradiation amount) is calculated every time a predetermined time elapses, and the growing space with the smallest difference is swapped to the position of the growing space with the largest difference.

[0090] Fifth Embodiment [Configuration] Next, a fifth embodiment of the present invention will be described with reference to the drawings. FIGS. 20 to 22 are diagrams illustrating the fifth embodiment. The fifth embodiment differs from the first to fourth embodiments in that sunlight and artificial light are irradiated only from above the cultivation space. Additionally, the control mechanism 8 includes a first removal filter that removes ultraviolet wavelength components from sunlight SL, a second removal filter that removes only infrared wavelength components from sunlight SL, and a light-blocking filter, and is configured to be switchable between these. Furthermore, the fifth embodiment differs from the first to fourth embodiments in that it measures the temperature of each cultivation space and controls the use and non-use of the second removal filter based on the measured temperature. Below, differences from the first to fourth embodiments will be described in detail, and overlapping portions will be omitted where appropriate.

[0091] FIG. 20 is a front cross-sectional view showing a schematic configuration example of a plant growing device 100 according to a fifth embodiment of the present invention, and FIG. 21 is a side cross-sectional view of the plant growing device 100 according to the fifth embodiment. FIG. 22 is a side cross-sectional view of the plant growing device of FIG. 26 in which the light source panel 77a has been moved to another position. As shown in FIGS. 25 to 27, the plant growing device 100 has a single light source unit 77 disposed above the growing spaces 6A, 6B, and 6C arranged closely to one another. In other words, the light source unit 77 is disposed near the growing spaces 6A, 6B, and 6C. The light source unit 77 includes a light source panel 77a and a transparent heat-shielding case (heat-shielding partition) 77b surrounding the light source panel 77a. The light source panel 77a is oriented horizontally, and the heat-shielding case 77b surrounding the light source panel 77a is also oriented horizontally.

[0092] Because light source unit 77 is disposed above cultivation spaces 6A, 6B, and 6C, light source panel 77a supplies artificial light L and L' from above to plants 3 in cultivation spaces 6A, 6B, and 6C. Plant cultivation 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 in which the plants have leaves that spread widely in horizontal or diagonal directions compared to their height.

[0093] The light source panel 77a is used in common for the multiple cultivation spaces 6A, 6B, and 6C, and supplies artificial light L to the cultivation spaces 6A, 6B, and 6C. However, the cultivation spaces 6A, 6B, and 6C use the light source panel 77a in a time-division manner (i.e., at different periods).

[0094] Like the heat-shielding case 7b of the fourth embodiment, the heat-shielding case 77b is made of a light-transmitting material, such as glass or transparent resin. The heat-shielding case 77b has a wall 77c interposed between the growing spaces 6A, 6B, and 6C and the light source panel 77a. The wall 77c is flat and horizontally oriented. The heat-shielding case 77b suppresses or inhibits heat radiation and heat conduction from the light source panel 77a, which is a heat source, to prevent overheating of the growing spaces 6A, 6B, and 6C.

[0095] In the fifth embodiment, the heat-shielding case 77b surrounds the entire light source panel 77a. However, the heat-shielding case 77b does not necessarily have to surround the entire light source panel 77a. For example, the top wall and side walls of the heat-shielding case 77b may be omitted. Furthermore, the portions of the heat-shielding case 77b other than the wall 77c between the light source panel 77a and the growing spaces 6A, 6B, and 6C do not have to be transparent.

[0096] As in the first embodiment, a blower (not shown), a refrigerant pipe or chamber (not shown), and / or fins may be provided to prevent overheating of the heat-shielding case 77b and the light source panel 77a. The interior of the heat-shielding case 77b may be evacuated to efficiently suppress heat conduction from the light source panel 77a. The height H from the plant support panel 5 to the wall 77c of the light source unit 77 is set to a size that allows artificial light L to be applied evenly and sufficiently to each leaf of a plant 3 that has grown to a certain extent.

[0097] However, the height H of the wall 77c of the light source unit 77 is preferably set to restrict excessive vertical growth of the plant 3. That is, the heat-shielding case 77b is preferably positioned relative to the plant 3 (disposed relative to the plant support panel 5) so as to restrict the longitudinal growth of the leaves of the plant 3 cultivated within the growing spaces 6A, 6B, and 6C. Specifically, the height H of the wall 77c of the heat-shielding case 77b is preferably set smaller than the maximum height that the upper ends of the leaves of the plant 3 are expected to reach if the heat-shielding case 77b were not present. In this case, the heat-shielding case 77b restricts excessive leaf growth of the plant 3, allowing the plant 3 to be grown in a small space (small height). In the fifth embodiment, the heat-shielding case 77b of the light source unit 77 has a length equal to or greater than the combined length of the growing spaces 6A, 6B, and 6C. The growing spaces 6A, 6B, and 6C are the spaces above the liquid fertilizer tanks 4A, 4B, and 4C, respectively.

[0098] The movement control device 30 controls a movement mechanism (not shown) to move the light source panel 77a of the light source unit 77 relative to the growing spaces 6A, 6B, and 6C. The light source panel 77a is used in common for the three growing spaces 6A, 6B, and 6C.

[0099] On the other hand, as shown in Figure 25, in the building 50A housing the plant growing device 100, only the ceiling wall 54 in the building 50 of the first embodiment is configured with a sunlight entrance window (not shown) made of a light-transmitting material over substantially the entire surface. The side walls 55 of the building 50A are configured with a light-impermeable wall material such as concrete. That is, the building 50A is capable of taking sunlight SL into the interior through the sunlight entrance window in the ceiling wall 54. This allows sunlight SL to be guided to the plants 3 inside the building by the sunlight entrance window in the ceiling wall 54. That is, the light entrance window in the ceiling wall 54 constitutes a sunlight guide mechanism. Meanwhile, a control mechanism 8 that removes specific wavelength components from sunlight SL is provided inside the ceiling wall 54 of the building 50A.

[0100] The control mechanism 8 of the fifth embodiment includes a first elimination filter that removes ultraviolet wavelength components from sunlight SL entering through a sunlight entrance window that constitutes the ceiling wall 54, a second elimination filter that removes infrared wavelength components from sunlight SL, and a light-shielding filter that blocks the entry of sunlight SL. The first elimination filter and the second elimination filter are, for example, roll-up filters that cover the sunlight entrance window when deployed and are positioned facing each other vertically. The control mechanism 8 is configured to be able to switch between using the first elimination filter and the second elimination filter simultaneously, using only the first elimination filter, and not using either filter. Specifically, using the first elimination filter and the second elimination filter simultaneously can remove ultraviolet and infrared wavelength components from sunlight SL. Furthermore, using the first elimination filter and not using the second elimination filter can remove only ultraviolet wavelength components from sunlight SL.

[0101] That is, the control mechanism 8 can irradiate the plant 3 with sunlight SL', from which ultraviolet and infrared wavelength components have been removed by the first and second elimination filters from sunlight SL incident through the sunlight entrance window in the ceiling wall 54. In addition, by using only the first elimination filter, sunlight SL'' from which only ultraviolet wavelength components have been removed can be irradiated to the plant 3. In other words, sunlight SL'' containing infrared wavelength components can be irradiated to the plant 3. Furthermore, the light-shielding filter used in the first embodiment can be switched between a light-transmitting state and a light-shielding state by applying and de-energizing it. This allows the sunlight SL to be blocked by de-energizing the light-shielding filter. Furthermore, although not shown, the plant growing device 100 also includes a temperature sensor 60 that measures the temperature of the growth spaces 6A, 6B, and 6C, and a sunlight irradiation control unit 62.

[0102] The sunlight irradiation control unit 62 controls the switching operation of the removal filter of the control mechanism 8 via the environmental control device 20 based on the temperatures of the growth spaces 6A, 6B, 6C obtained from the temperature sensor 60, thereby controlling the irradiation of sunlight SL' and sunlight SL" into the growth spaces 6A, 6B, 6C. Although not shown, the sunlight irradiation control unit 62 includes a processor and a ROM that stores control programs, setting data, etc. In addition, it includes a RAM for storing data read from the ROM and calculation results required in the processor's calculation process, and an I / F that mediates data input and output to and from external devices. These are connected to each other so that data can be exchanged by a bus, which is a signal line for transferring data.

[0103] Specifically, the sunlight irradiation control unit 62 acquires the temperatures of the growth spaces 6A, 6B, and 6C from the temperature sensor 60 before starting the irradiation process of sunlight SL' for photosynthesis of the plants 3. Then, the sunlight irradiation control unit 62 determines whether a judgment temperature (e.g., average temperature, maximum temperature, etc.) based on the acquired temperature is equal to or lower than a predetermined temperature, and if it is determined that the judgment temperature is not equal to or lower than the predetermined temperature, for example, the control unit 62 issues a control command to the environmental control device 20 so that the control mechanism 8 deploys the first and second removal filters. In response to the control command from the sunlight irradiation control unit 62, the environmental control device 20 issues a command to the control mechanism 8 to deploy the first and second removal filters. In this way, the growth spaces 6A, 6B, and 6C are irradiated with sunlight SL' from which ultraviolet and infrared wavelength components have been removed. Thereafter, during irradiation of the sunlight SL′, the sunlight irradiation control unit 62 acquires the temperatures of the growth spaces 6A, 6B, and 6C from the temperature sensor 60 at predetermined time intervals, and when it determines that the judgment temperature based on the acquired temperatures is, for example, equal to or lower than a predetermined temperature, issues a control command to the environmental control device 20 so that the control mechanism 8 retracts the second elimination filter and deploys only the first elimination filter. In response to the control command from the sunlight irradiation control unit 62, the environmental control device 20 issues a command to the control mechanism 8 to retract the second elimination filter and deploy only the first elimination filter. This results in irradiation of the growth spaces 6A, 6B, and 6C with sunlight SL″ that contains infrared wavelength components and has ultraviolet wavelength components removed. In other words, when the temperatures of the growth spaces 6A, 6B, and 6C are relatively low, infrared irradiation is actively performed, and when the temperatures of the growth spaces 6A, 6B, and 6C are relatively high, infrared irradiation is stopped.

[0104] In the fifth embodiment, the determination process is performed at predetermined time intervals during the sunlight SL′ irradiation process, and the removal filter is switched accordingly. However, this configuration is not limited to this. For example, the temperature may be acquired from the temperature sensor 60 immediately before the start time of the sunlight irradiation process for photosynthesis. If the temperature is higher than a predetermined temperature, the first and second removal filters are deployed, and if the temperature is equal to or lower than the predetermined temperature, only the first removal filter is deployed. Thereafter, the removal filter is not switched. In the fifth embodiment, the sunlight irradiation control unit 62 controls the control mechanism 8 via the environmental control device 20. However, this configuration is not limited to this, and the sunlight irradiation control unit 62 may directly control the control mechanism 8. The movement control device 30 of the fifth embodiment moves the light source panel 77a in the heat-shielding case 77b along the longitudinal direction of the fixed growth spaces 6A, 6B, and 6C without moving the heat-shielding case 77b.

[0105] The movement control device 30 can also create a state in which the plants 3 in any one of the cultivation spaces 6A, 6B, and 6C are irradiated with the artificial light L output from the light source panel 77a. Also, the movement control device 30 can create a state in which the plants 3 in any of the cultivation spaces 6A, 6B, and 6C are not irradiated with the artificial light L from the light source panel 77a.

[0106] On the other hand, in the example shown in Figure 22, the amount of sunlight SL' or SL'' irradiated into the growth space 6A is insufficient, and the plants 3 inside the growth space 6A are irradiated with artificial light L output from the light source panel 77a. This compensates for the insufficient amount of visible light irradiated into the growth space 6A. The movement control device 30 moves the light source panel 77a inside the heat-shielding case 77b along the longitudinal direction of the growth spaces 6A, 6B, and 6C relative to the fixed growth spaces 6A, 6B, and 6C without moving the heat-shielding case 77b.

[0107] Furthermore, the sunlight irradiation control unit 62 can issue a command to the control mechanism 8 via the environmental control device 20 based on the temperature of the cultivation space obtained from the temperature sensor 60, and switch between irradiating the plants 3 with sunlight SL' from which ultraviolet and infrared wavelength components have been removed, and sunlight SL" from which only the ultraviolet wavelength component has been removed. For example, when the temperature is low in winter, the plants 3 can be actively irradiated with sunlight SL" that includes infrared rays, and when the temperature is high in summer, the plants 3 can be irradiated with sunlight SL' that does not include infrared wavelength components. This can reduce the energy required by the air conditioning system 12 to control the air temperature in the plant cultivation spaces 6A, 6B, and 6C.

[0108] Furthermore, the heat-shielding case 77b thermally isolates the growing spaces 6A, 6B, and 6C from the first and second light source panels 77v and 77u, making them less susceptible to the heat. In other words, the heat-shielding case 77b prevents the growing spaces 6A, 6B, and 6C from overheating. This reduces the energy required by the air-conditioning system 12 to control the air temperature in the growing spaces 6A, 6B, and 6C, making it easier to maintain the growing spaces 6A, 6B, and 6C in an environment suitable for the plants being grown.

[0109] Furthermore, the number of light source panels 77a does not need to correspond to the number of growing spaces 6A, 6B, and 6C. In this embodiment, a single light source panel 77a can be used in common for the growing spaces 6A, 6B, and 6C. This prevents an increase in the number of light source panels 77a. The configurations of the second to fourth embodiments may be applied to the fifth embodiment if applicable.

[0110] 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 included within the scope of the invention.

[0111] L, L'...artificial light, SL, SL', SL''...sunlight, 1, 1A, 1B, 1C, 1D, 100...plant cultivation device, 2, 2X, 2Y...cultivation device, 3...plant, 4, 4A, 4B, 4C...liquid fertilizer tank, 6A, 6B, 6C...cultivation space, 7, 77...light source unit, 7a, 77a...light source panel (artificial light source), 7b, 77b...heat-shielding case (heat-shielding partition), 8...control mechanism, 8a, 8b...filter section, 13...housing, 19...irradiation amount measuring device (irradiation amount measuring section, ultraviolet irradiation amount measuring section), 20...environmental control device, 30...movement control device (movement control section), 50, 50A...building, 52, 55...side wall, 54...ceiling wall, 60...temperature sensor, 62...sunlight irradiation control section

Claims

1. A plant growing device that grows plants using artificial light, comprising: a sunlight guiding mechanism that guides sunlight to the plant; a control mechanism that controls the wavelength components of the sunlight so as to remove specific wavelength components from the sunlight before it is irradiated to the plant; and an artificial light source that can irradiate the plant with artificial light for growing the plant.

2. A plant growing device as claimed in claim 1, comprising: an irradiance measuring unit that measures the amount of irradiance of sunlight on the plant after the wavelength components have been removed by the control mechanism; and a control unit that, when the amount of irradiance measured by the irradiance measuring unit is less than the amount of irradiance required for growing the plant, controls the irradiation of the artificial light from the artificial light source on the plant so as to reach the required amount of irradiance.

3. The plant growing device according to claim 1, wherein the control mechanism removes infrared wavelength components from the sunlight.

4. The plant growing device according to claim 1, wherein the control mechanism removes ultraviolet wavelength components from the sunlight.

5. A plant growing device as claimed in claim 2, comprising: a plurality of growth spaces, each of which grows at least one portion of the plant above the roots; a movement mechanism which moves each of the growth spaces to a predetermined position within the sunlight irradiation range; and a movement control unit which controls the movement mechanism, wherein the irradiation amount measuring unit measures, for each growth space, the amount of sunlight irradiated from the specific wavelength component removed onto the plant grown in that growth space, and the movement control unit acquires from the irradiation amount measuring unit the amount of irradiation onto the plant grown in each of the growth spaces at predetermined time intervals, and controls the movement mechanism based on the difference in the amounts of irradiation among the plurality of growth spaces to replace a growth space in which the difference is relatively small with another growth space in which the difference is relatively large.

6. A plant growing device as claimed in claim 2, comprising a plurality of growing spaces arranged in close proximity to each other, with at least one plant being grown in each growing space for a portion above the roots; the artificial light source being used in common for the plurality of growing spaces; a movement mechanism for moving the artificial light source relatively to the plurality of growing spaces; and a movement control unit for controlling the movement mechanism, wherein the irradiation amount measuring unit measures the irradiation amount of a plant grown in each of the growing spaces, and when the irradiation amount measured by the irradiation amount measuring unit is less than the irradiation amount necessary for growing the plant, the movement control unit controls the movement mechanism so that the artificial light source moves relatively to an irradiation position of the artificial light source for a growth space in which a plant is grown with less irradiation amount.

7. A plant growing device as claimed in claim 2, comprising a plurality of housings each defining a closed growth space in which at least one portion above the roots of a plant is grown, the artificial light source being shared by the plurality of housings, a movement mechanism for moving each of the housings relative to the artificial light source, and a movement control unit for controlling the movement mechanism, wherein the irradiation amount measuring unit measures the irradiation amount of a plant grown in each of the growth spaces, and when the irradiation amount measured by the irradiation amount measuring unit is less than the irradiation amount necessary for growing the plant, the movement control unit controls the movement mechanism to move the housing having the growth space in which a plant is grown with less than that irradiation amount to a position irradiated by the artificial light source.

8. A plant growing device as claimed in claim 1, characterized in that the control mechanism has a first filter which removes the ultraviolet wavelength components from the sunlight and a second filter which removes the infrared wavelength components, and is configured to be able to switch between at least sunlight to which the first and second filters have been applied and sunlight to which only the first filter has been applied, and further comprising: a growing space for growing at least one portion of the plant above the roots; a temperature sensor which measures the temperature of the growing space; and a sunlight irradiation control unit which controls the control mechanism so that the plant is irradiated with sunlight to which only the first filter has been applied when the temperature measured by the temperature sensor is equal to or higher than a predetermined temperature.

9. A plant cultivation method for cultivating a plant using artificial light, comprising: a sunlight guiding step of guiding sunlight to the plant; and a control step of controlling the wavelength components of the sunlight so as to remove specific wavelength components from the sunlight before it is irradiated to the plant.

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