LED line light source unit for photosynthetic organism artificial culturing device and photosynthetic organism artificial culturing device using same

Abstract

[Problem] To provide an LED line light source unit for a photosynthetic organism artificial culturing device, the LED line light source unit increasing the cultivation yield of photosynthetic organisms while suppressing the cost of electricity. [Solution] The arrangement of LED elements in an LED line light source unit 100 for a photosynthetic organism artificial culturing device includes a red LED element 110 of 640-690 nm, a blue LED element 120 of 400-470 nm, and a far infrared LED element 130 of 710-740 nm. The number of red LED elements 110 accounts for approximately 70%, the number of blue LED elements 120 accounts for approximately 15%, and the number of far infrared LED elements 130 accounts for approximately 15%. The LED line light source unit is dispersed and arranged in a one-dimensional one-row arrangement, a two-dimensional three-row arrangement, and a three-dimensional three-row arrangement. The arrangement of the blue LED elements 120 and the far infrared LED elements 130 is alternately switched. A constant current control circuit 140 is provided, and driving is carried out at a constant current of a value that is lower than the value of the rated current of each LED element, that is, at a constant current value in a range of 1 / 4 to 3 / 4 the value of the rated current.

Description

LED line light source unit for photosynthetic organism artificial culture device and photosynthetic organism artificial culture device using the same

[0001] The present invention relates to an LED line light source unit for use in an artificial photosynthetic organism culture device and an artificial photosynthetic organism culture device using the same. The photosynthetic organisms are not particularly limited, and can be a wide range of organisms, including agricultural crops, fruit and vegetable crops, herbaceous plants, carbohydrate-producing organisms, and biofuel-producing organisms.

[0002] In recent years, artificial plant cultivation techniques that use artificial lighting indoors, rather than traditional farming methods that use natural light from the outside, have been gaining attention. In artificial cultivation, it has become possible to control plant flowering and promote growth by irradiating plants with light of wavelengths appropriate for the plant species, such as blue, red, or far-red. As a light source for artificial lighting, the development of high-power LED elements (light-emitting diode elements) has progressed in recent years, and so-called LED lighting fixtures have begun to be used in place of traditional white light bulbs and fluorescent lamps. In particular, white LED elements are capable of emitting light of multiple wavelengths, making them suitable for artificial lighting in artificial plant cultivation devices. Furthermore, their compact size, energy-saving, and long lifespan have also given them momentum for widespread use. Furthermore, because LED elements emit light of a relatively uniform wavelength and generate relatively little heat, artificial lighting devices incorporating an array of multiple LED elements have been proposed for use as lighting fixtures for artificial cultivation.

[0003] Prior art has proposed an artificial cultivation device using an LED lighting device with a large number of LED elements. The plant cultivation device disclosed in Patent Document 1 (JP 2013-17397 A) includes a cultivation rack 3 with a mounting shelf 4 on which a cultivation tank 2 is placed, and an LED lighting device 5 arranged at intervals above the mounting shelf 4, as shown in FIG. 11 . The cultivation rack 3 is constructed by arranging multiple vertical supports 8, connecting the vertical supports 8 with horizontal members 9 to form a single vertical frame 7, and connecting a pair of left and right vertical frames 7A, 7B with connecting members 18 to form the cultivation rack 3. Multiple support members 6 protrude from the sides of the vertical supports 8 of the vertical frame 7, and LED lighting devices 5 are attached to these support members 6. As described in paragraph 0028 of the same publication, the LED lighting device 5 is fixed to the vertical supports 8 by screws, rivets, or the like, to the receiving portions 32 of the support members 6.

[0004] Furthermore, Patent Document 2 (JP 2015-006165 A) discloses a plant cultivation device in which, as shown in Fig. 12, an LED lighting device 5 is arranged on a cultivation rack. The LED lighting device 5 includes a picture frame-like frame 15, a plurality of LED lighting devices 16 detachably attached to the frame 15, and a plate-like reflecting member 17 detachably attached to the frame 15 above the LED lighting devices 16 and with its reflective surface facing downward. The left and right ends of the LED lighting device 16 are fitted into notches 23 in lighting device receiving portions 21 of left and right frame members 18 of the horizontal frame 15, and the LED lighting device 16 is fixed by a pressing member 25 detachably attached to the horizontal frame 15. The left and right ends of the LED lighting device 16 are screwed from above by the pressing member 25 via an elastic member 29, thereby fixing the LED lighting device 16.

[0005] In this way, in both Patent Document 1 and Patent Document 2, a structure called a cultivation rack is assembled, and the ends of the LED lighting fixtures are placed in predetermined positions on the cultivation rack, and then fixed with screws, rivets, etc., thereby arranging them in the predetermined positions and creating a stable state.

[0006] JP 2013-017397 A JP 2015-006165 A

[0007] The first problem with using conventional LED lighting devices as light sources in plant factories is the low photosynthetic energy efficiency relative to the electrical energy supplied. The LEDs used in conventional technology consisted of a large number of inexpensive LEDs widely used for general lighting, arrayed together to emit white light. White LEDs, which contain all wavelengths, are suitable for a wide range of applications, including indoor lighting, office lighting, and factory lighting. To reduce the cost of LED elements, white LEDs have been mass-produced and used for a variety of purposes. As part of this trend, white LEDs have also become widely used as light sources for the artificial cultivation of photosynthetic organisms, such as plants. However, because white light is synthesized by converting blue wavelength light emitted by blue LEDs using phosphors, the wavelengths required for photosynthesis are actually limited, resulting in low cost but low photosynthetic energy efficiency. This, in turn, leads to high running costs. The proportion of nuclear power in the energy mix has declined due to the recommendation of zero-carbon power generation to prevent global warming, as well as the impact of the Great East Japan Earthquake. Furthermore, global conflicts such as the war in Ukraine have led to higher crude oil prices, and the weak yen has added to the problem, causing the cost of thermal power generation to rise. As a result, electricity prices have risen and the burden of electricity costs has become relatively greater.

[0008] The second problem with using conventional LED lighting equipment as a light source in plant factories is the issue of plant growth. White light uses phosphors to convert blue light into green and red light with longer wavelengths, but the 660nm and 730nm red components necessary for plant growth are severely lacking, causing problems with plant growth. This is a drawback of phosphor-based lighting equipment. While it is possible to convert the wavelength of the irradiated light using phosphors, this method results in even greater electrical energy loss, making it unsuitable for an era of high-cost electricity.

[0009] A third problem with using conventional LED lighting devices as light sources in plant factories is that they are driven at rated current and voltage, which reduces the efficiency of each LED in emitting light at wavelengths suitable for photosynthesis. Because LED elements are expensive, the focus in applying them to various devices has been on how to efficiently drive white LED elements. As a result, white light irradiation has been the focus, and driving them at rated current and voltage as recommended by white LED element manufacturers has been considered the most efficient way to generate power, making rated drive the standard. Driving white LED elements at rated drive is designed to increase the light output of the light-emitting diode and achieve high illuminance and light intensity, which can be considered a rational operation in some sense. However, rated drive of white LED elements increases the light output across the entire wavelength range of the white LED, i.e., the total light output across the entire visible light spectrum. Meanwhile, it is known that the light wavelengths required for growth by photosynthetic organisms are not the entire visible light spectrum, but three specific wavelength ranges. In other words, when driving an LED lighting device, it is necessary to consider driving that increases the amount of light emitted in these three wavelength bands in the specific region.

[0010] In view of the above problems, the present invention aims, first, to improve the energy efficiency used for photosynthesis relative to the electrical energy supplied, second, to suppress wavelength unevenness in the irradiated light to make the wavelengths necessary for photosynthesis as uniform as possible, and to provide irradiated light with little wavelength unevenness, and third, to provide advantageous driving to obtain light with wavelengths effective for photosynthesis without being bound by rated current and rated voltage values, and to provide an LED line light source unit for a photosynthetic organism artificial culture device that increases the yield from the cultivation of photosynthetic organisms, and a photosynthetic organism artificial culture device using the same.

[0011] In order to achieve the above object, the LED line light source unit for a photosynthetic organism artificial culture device of the present invention is an LED line light source unit for a photosynthetic organism artificial culture device in which a large number of LED elements are arranged for use in an apparatus for artificially culturing photosynthetic organisms, wherein the LED elements are LED elements using power semiconductors, the rated current value of the LED elements is 350 mA or more, and the arrangement of the LED elements in the LED line light source unit for a photosynthetic organism artificial culture device is a distributed arrangement configuration in which red LED elements that emit light in the red wavelength band of 640 to 690 nm, blue LED elements that emit light in the blue wavelength band of 400 to 470 nm, and far-infrared LED elements that emit light in the far-infrared wavelength band of 710 to 740 nm are distributed.

[0012] According to the LED line light source unit for a photosynthetic organism artificial culture device of the present invention, the LED elements within the unit emit light with wavelengths effective for photosynthesis in photosynthetic organisms, i.e., the red wavelength band of 640-690 nm, the blue wavelength band of 400-470 nm, and the far-infrared wavelength band of 710-740 nm, so that the input electrical energy is effectively utilized for photosynthesis in photosynthetic organisms, improving electrical energy efficiency and photosynthetic efficiency. Furthermore, by using power semiconductors in the blue, red, and far-infrared wavelength bands, it is possible to effectively emit light in these specified wavelength bands, without the need to emit light of all wavelengths as with conventional white LEDs.

[0013] Next, the ratio of the number of red LED elements, blue LED elements, and far-infrared LED elements in the distributed arrangement of the LED elements in the LED line light source unit for the photosynthetic organism artificial culture device of the present invention is preferably in the range of 6:4 to 8:2, where the ratio of the number of red LED elements to the total number of blue LED elements and far-infrared LED elements is 6:4 to 8:2. For example, the ratio of the number of red LED elements to the total number of blue LED elements and far-infrared LED elements is 7:3. To make it easier to understand, an example of the number of red LED elements, blue LED elements, and far-infrared LED elements, when the ratio is 6:4, could be 60% red LED elements, 20% blue elements, and 20% far-infrared LED elements. Furthermore, when the ratio is 7:3, could be 70% red LED elements, 15% blue elements, and 15% far-infrared LED elements. In addition, as an example of a case where the ratio is 8:2, the ratio could be 80% red LED elements, 10% blue elements, and 10% far-infrared LED elements. With the above configuration, light irradiation of the necessary and effective light wavelengths for photosynthetic organisms can be appropriately distributed, allowing for even growth.

[0014] Next, we will discuss the arrangement of the LED elements in the distributed arrangement of the LED line light source unit for the photosynthetic organism artificial culture device of the present invention. In the distributed arrangement, in the longitudinal direction, which is the arrangement direction of the LED elements, it is preferable that the arrangement of the LED elements in at least a portion of the longitudinal direction is such that one to several red LED elements are arranged, followed by one to several blue LED elements, one to several red LED elements, and then one to several far-infrared LED elements. In other words, even if the ratio of the number of LED elements is, as described above, for example, 70% red LED elements, 15% blue elements, and 15% far-infrared LED elements, if the red elements are arranged continuously in a certain range and neither blue elements nor far-infrared elements are arranged in that range, the balance of the irradiated light will be poor. Therefore, a moderate distribution of the LED elements is preferable. Assuming that the proportion of red LED elements is high, a preferable arrangement is one in which the ratio of red LED elements to blue LED elements is high, alternating with each other while maintaining a high proportion of red LED elements, such as a small-scale arrangement of several red LED elements, a small-scale arrangement of several blue LED elements, a small-scale arrangement of several red LED elements, and a small-scale arrangement of several far-infrared LED elements.With the above configuration, light irradiation of the necessary and effective wavelengths for photosynthetic organisms can be appropriately distributed, allowing for even growth.

[0015] Next, the arrangement of the LED elements in the distributed LED element arrangement can be not only a one-dimensional single-row arrangement, but also a two-dimensional three-row arrangement. In this case, if one row of the three rows is entirely red LED elements, the other row is entirely blue LED elements, and the remaining row is entirely far-infrared LED elements, the irradiated light will inevitably be biased directly below the LED line light source unit for the photosynthetic organism artificial culture device. Even in a two-dimensional three-row arrangement, an arrangement that alleviates the bias of the irradiated light and makes it easier to distribute it is preferable. Therefore, in the arrangement of the LED elements in the longitudinal direction, which is the direction of arrangement, there are three parallel rows of LED elements along the longitudinal direction, and from the end, each row is composed of a first row of LED elements, a second row of LED elements, and a third row of LED elements. The second row of LED elements in the center is the row containing red LED elements, and blue LED elements and far-infrared LED elements are arranged in the first row of LED elements and the third row of LED elements, respectively, and it is preferable that they are arranged alternately on either side of the second row of LED elements.

[0016] That is, if a blue LED element is arranged in the first LED element row, a far-infrared LED element is arranged next to it, and a blue LED element is arranged next to it. In this way, blue LED elements and far-infrared LED elements are arranged alternately in the first LED element row. On the other hand, the third LED element row is arranged in the opposite way to the above, that is, if a far-infrared LED element is arranged in the third LED element row, a blue LED element is arranged next to it, and a far-infrared LED element is arranged next to it. In this way, far-infrared LED elements and blue LED elements are arranged alternately in the third LED element row. Red LED elements are arranged consecutively in the second central LED element row. This relationship is as if blue LED elements and far-infrared LED elements are arranged alternately in the first LED element row and the third LED element row, sandwiched between the second central LED element row containing red LED elements. With the above arrangement, the macro ratio of the red LED elements, blue LED elements, and far-infrared LED elements is in the range of 6:4 to 8:2, and light irradiation is possible that promotes good photosynthesis with the irradiated light being appropriately dispersed.

[0017] Next, we will discuss the driving of the LED elements in the LED line light source unit for a photosynthetic organism artificial culture device of the present invention. In the LED element package containing the blue LED element, the red LED element, and the far-infrared LED element, it is preferable that the substrate on which each LED element is mounted is made of a ceramic or metallic material and satisfies the following conditions 1 and 2. (Condition 1) The thermal conductivity of the LED element package is 20 W / m·k or higher (W is a unit representing the power of heat transfer, m is the thickness in the direction of heat conduction, and k is the thermal conductivity). (Condition 2) The current supplied to the LED element package is in the range of 1 / 4 to 3 / 4 (25% to 75%) of the rated current value of each LED element. The LED line light source unit for a photosynthetic organism artificial culture device of the present invention is configured to include a constant current control circuit for current control. The red LED element, blue LED element, and far-infrared LED element in the distributed configuration are each driven by a constant current supplied from the constant current control circuit. Each LED element is driven at a constant current within a range of 1 / 4 to 3 / 4 of the rated current, that is, within a range of (25% to 75%) of the rated current.

[0018] These innovations aim to improve luminous efficiency while suppressing temperature rise of the LED chips within the light source unit. To reduce the power costs of LED light sources, LED packages with high luminous efficiency and driving them to further enhance luminous efficiency are used. Here, a package with high luminous efficiency means that the substrate on which the LED chips are mounted has high thermal conductivity (ceramic or metal). This is because it is important to quickly transfer heat from each LED element out of the system and suppress heat buildup within the LED package. Furthermore, the lower the current, the more the LED chip temperature rise can be suppressed, improving luminous efficiency. However, LED packages made of the above materials have a certain resistance component due to the element's material composition, so there is a limit to how much luminous efficiency can be improved. In prior art, LED chips used in plant factories have often been white light sources for illumination, using low-cost materials such as epoxy resin as heat diffusion materials in the packaging. However, in terms of luminous efficiency, alumina substrates have high thermal conductivity, which reduces temperature rise within the LED chip and improves luminous efficiency.

[0019] The above-described LED element driving method can be applied to the above-described one-dimensional, single-row distributed arrangement of LED elements, as well as the above-described two-dimensional, three-row distributed arrangement of LED elements. By implementing the above-described driving method, the life of the LED line light source unit can be extended. Since LED elements deteriorate more rapidly as the applied voltage and current increase, driving them at low voltages and currents is advantageous when prioritizing the life of the LED elements. However, when the applied voltage and current are lower than the rated voltage and current, the amount of light emitted by the LED elements decreases, resulting in reduced light intensity. To solve this problem, the LED elements can be driven at a driving voltage and current lower than the rated voltage and current, while increasing the number of LED elements to compensate for the reduced light intensity. While increasing the number of LED elements installed in an LED line light source unit increases costs, this disadvantage is offset by the benefit of extending the life of the LED elements.

[0020] Next, the LED line light source unit for a photosynthetic organism artificial culture device of the present invention can be applied to a photosynthetic organism artificial culture device. In the above configuration, the LED line light source unit for a photosynthetic organism artificial culture device is preferably used on each shelf of a vertically multi-tiered configuration, with each tier preferably being 100 cm or less in height, and the LED elements using the power semiconductors are preferably spaced apart from the leafy plants at a short distance of 10 cm to 100 cm, so that light from the LED elements using the power semiconductors is irradiated at this short distance. The photosynthetic organism artificial culture device of the present invention can be configured to include an LED line light source unit for a photosynthetic organism artificial culture device, a light source support structure that supports the LED line light source unit for a photosynthetic organism artificial culture device in a predetermined position and orientation, and a photosynthetic organism support structure that supports the photosynthetic organism facing the LED line light source unit for a photosynthetic organism artificial culture device. In addition, the driving configuration of the LED elements in the LED line light source unit for the photosynthetic organism artificial culture device applied to the photosynthetic organism artificial culture device can be applied to the above-mentioned one-dimensional, single-row distributed arrangement configuration of the LED elements, and can also be applied to the above-mentioned two-dimensional, three-row distributed arrangement configuration of the LED elements.

[0021] The first promising industry for applying the photosynthetic organism artificial culture device of the present invention is agriculture. The inventor, Sosuke Naito, has conducted extensive research into low-cost, operational agriculture that uses artificial lighting from LED elements instead of sunlight, and is convinced that agriculture is a promising industry for applying the photosynthetic organism artificial culture device of the present invention. The second promising industry for applying the photosynthetic organism artificial culture device of the present invention is the production of plant-derived biofuel. The production of plant-derived biofuel is considered a new energy source that can replace conventional fossil fuels. The inventor, Sosuke Naito, has conducted extensive research into low-cost, operational production of plant-derived biofuel that uses artificial lighting from LED elements, and is convinced that the production of plant-derived biofuel is a promising industry for applying the photosynthetic organism artificial culture device of the present invention.

[0022] According to the LED line light source unit for a photosynthetic organism artificial culture device of the present invention, the LED elements within the unit emit light with wavelengths effective for photosynthesis in photosynthetic organisms, i.e., the red wavelength band of 640 to 690 nm, the blue wavelength band of 400 to 470 nm, and the far-infrared wavelength band of 710 to 740 nm. This allows the input electrical energy to be effectively utilized for photosynthesis in photosynthetic organisms, resulting in increased electrical energy efficiency and improved photosynthetic efficiency. This allows for excellent light irradiation for photosynthetic organism cultivation, resulting in increased yields. Furthermore, light irradiation with the necessary and effective wavelengths for photosynthetic organisms can be appropriately distributed to ensure even cultivation. Furthermore, the photosynthetic organism artificial culture device of the present invention can reduce electricity costs and increase yields from the cultivation of photosynthetic organisms. It can be applied to agriculture and the production of plant-derived biofuels.

[0023] 1 is a diagram showing an LED line light source unit 100a for a photosynthetic organism artificial culture device, which is an example of a configuration in which LED elements are arranged in a one-dimensional single row and a distributed configuration. 2 is a diagram showing an LED line light source unit 100b for a photosynthetic organism artificial culture device, which is an example of a configuration in which LED elements are arranged in a two-dimensional three-row configuration and a distributed configuration. 3 is a diagram showing an LED line light source unit 100c for a photosynthetic organism artificial culture device, which is an example of a configuration in which LED elements are arranged in a three-dimensional three-row configuration and a distributed configuration. 4 is a diagram showing a simplified example of driving each LED element using a constant current control circuit 140. 5 is a diagram showing a simplified example of the configuration of a photosynthetic organism artificial culture device 200 of Example 2. 6 is a photograph of the exterior of a prototype LED line light source unit 100 for a photosynthetic organism artificial culture device. 7 is a diagram comparing the energy distribution of the wavelength of the irradiation light of the LED line light source unit 100 for a photosynthetic organism artificial culture device according to the present invention and a general white LED line light source unit. 8 is a diagram showing a demonstration system of an assembled photosynthetic organism artificial culture device 200. 1 is a diagram showing a comparison of yields of plants grown for three weeks from planting on April 18, 2024 until harvest on May 7, as a growth period. 2 is a diagram showing a comparison of yields of plants grown for three weeks from planting on May 2, 2024 until harvest on May 23, as a growth period. 3 is a diagram showing a comparison of yields of plants grown for three weeks from planting on May 2, 2024 until harvest on May 23. 4 is a diagram showing a conventional plant cultivation device disclosed in Patent Document 1 (JP 2013-17397 A). 5 is a diagram showing a conventional plant cultivation device disclosed in Patent Document 2 (JP 2015-006165 A).

[0024] Hereinafter, with reference to the drawings, examples of the LED line light source unit for a photosynthetic organism artificial culture device and the photosynthetic organism artificial culture device of the present invention will be described. It goes without saying that the scope of the present invention is not limited to the specific applications, shapes, numbers, etc. shown in the following examples. As Example 1, an LED line light source unit 100 for a photosynthetic organism artificial culture device will be described. As Example 2, an example configuration of a photosynthetic organism artificial culture device 200 incorporating an LED line light source unit 100 for a photosynthetic organism artificial culture device as a light source will be shown.

[0025] An example of the basic configuration of the LED line light source unit 100 for a photosynthetic organism artificial culture device according to Example 1 of the present invention is shown. Examples of the arrangement of LED elements in the LED line light source unit 100 for a photosynthetic organism artificial culture device include a one-dimensional single-row arrangement, a two-dimensional three-row arrangement, and a three-dimensional three-row arrangement in the longitudinal direction, which is the arrangement direction of the LED elements. FIG. 1 is a diagram showing an LED line light source unit 100a for a photosynthetic organism artificial culture device, which is an example of a configuration in which the LED elements are arranged in a one-dimensional single row and in a distributed configuration. FIG. 2 is a diagram showing an LED line light source unit 100b for a photosynthetic organism artificial culture device, which is an example of a configuration in which the LED elements are arranged in a two-dimensional three-row arrangement and in a distributed configuration. FIG. 3 is a diagram showing an LED line light source unit 100c for a photosynthetic organism artificial culture device, which is an example of a configuration in which the LED elements are arranged in a three-dimensional three-row arrangement and in a distributed configuration.

[0026] Figures 1, 2, and 3 each show a simplified diagram of the LED line light source unit 100 for a photosynthetic organism artificial culture device. Figure 1(a) is a front view showing the LED elements from the front, and Figure 1(b) is an enlarged view of a portion of the LED elements to clearly show their arrangement. Figure 1(c) is a vertical cross-sectional view enlarged from the A-A line cross-section. Figure 1(d) is a vertical cross-sectional view enlarged from the B-B line cross-section. Figure 2(a) is a front view showing the LED elements from the front, and Figure 2(b) is an enlarged view of a portion of the B-B line cross-section to clearly show their arrangement in three two-dimensional rows. Figure 2(c) is a vertical cross-sectional view enlarged from the C-C line cross-section, and Figure 2(d) is a cross-sectional view along 102b1. Figure 2(e) is a horizontal cross-sectional view enlarged from the D-D line cross-section. Figure 2(f) is a cross-sectional view showing the cross-section of the next LED element adjacent to the D-D line. Figure 3(a) is a front view of the LED elements, and Figure 3(b) is an enlarged view of a portion of the LED elements in the three three-dimensional rows to make the arrangement easier to understand. Figure 3(c) is an enlarged longitudinal cross-sectional view taken along line E-E, and Figure 3(d) is a cross-sectional view taken along line 102b1. Figure 3(e) is an enlarged transverse cross-sectional view taken along line F-F. Figure 3(f) is a cross-sectional view showing the cross-section of the LED element in the next row adjacent to line F-F. In the cross-sectional view, adjacent LED elements are superimposed on each cross-section to make it easier to understand the positional relationship and light irradiation range of each LED element.

[0027] First, we will explain the LED line light source unit 100a for photosynthetic organism artificial culture devices, which is an example of a configuration in which the LED elements are arranged in a one-dimensional array and a distributed configuration, as shown in Figure 1. As shown in Figure 1(a), a large number of LED elements are arranged in a one-dimensional array. This one-dimensional array of LED elements is numbered 101a. The LED element array 101a of the LED line light source unit 100a for photosynthetic organism artificial culture devices has a distributed configuration in which a large number of red LED elements 110 emitting light in the red wavelength band of 640 to 690 nm, blue LED elements 120 emitting light in the blue wavelength band of 400 to 470 nm, and far-infrared LED elements 130 emitting light in the far-infrared wavelength band of 710 to 740 nm are arranged in a one-dimensional array.

[0028] The LED element array 101a is a line of many LED elements arranged along an electronic substrate 150. The electronic substrate 150 is not shown with electrical wiring or electronic circuits, but is generally assumed to have a configuration for driving the LED elements. Each LED element (110, 120, 130) has an LED element light-emitting surface on the front side and an electrode surface on the back side. In this example, the LED elements are surface-mounted (SMD) LED elements.

[0029] Here, the electronic substrate 150 forms an LED element package that includes a moderate number of blue LED elements 110, red LED elements 120, and far-infrared LED elements 130. The material of the LED element package substrate on which each LED element is mounted may be a ceramic material or a metal material. The electronic substrate 150 of the present invention satisfies the following conditions 1 and 2. <Condition 1> The thermal conductivity of the electronic substrate 150 is 20 W / m·k or more (W is a unit representing the power of heat transfer, m is the thickness in the direction of heat conduction, and k is the thermal conductivity). <Condition 2> The current supplied to the electronic substrate 150 is in the range of 1 / 4 to 3 / 4 of the rated current value of each LED element.

[0030] These conditions are necessary to increase the luminous efficiency while suppressing the temperature rise of the LED elements 110, 120, and 130. Effective measures to reduce the power costs of each LED element include, first, using LED packages with high luminous efficiency for each LED element rather than general LED packages. Here, a package with high luminous efficiency means that the substrate on which the LED element is mounted is made of a material with high thermal conductivity (ceramic or metal). This allows generated heat to be quickly transferred outside the system, thereby suppressing the rise in temperature within the LED package. Second, adopting a driving method that increases luminous efficiency. Reducing the driving current suppresses the temperature rise of the LED elements, thereby improving luminous efficiency. This means that the unit power consumption can be reduced. However, since the LED package has a certain resistance component due to the material components of the element, there is a lower limit to how much driving current can be reduced. The LED elements used in conventional plant factories use low-cost materials such as epoxy resin as the packaging substrate material, but this is not the best choice in terms of luminous efficiency, and due to changes in the business environment such as rising electricity costs, inventor Sosuke Naito has found the above <Condition 1> and <Condition 2> to be the conditions required for an artificial light source for plant factories that is suitable for the new business environment.

[0031] The emission wavelength of the LED element can be selected according to the intended use, and a variety of wavelengths are possible. An LED element with an emission wavelength that includes many wavelengths effective for photosynthesis in photosynthetic organisms is preferable. While this depends on the type of photosynthetic organism and the type of chloroplasts it possesses, wavelengths that are generally easily absorbed by chlorophyll a, chlorophyll b, and beta-carotene and related to photosynthesis and growth are considered to be efficiently utilized for photosynthesis in the ranges of 400-470 nm (blue wavelength), 640-690 nm (red wavelength), and 710-740 nm (far-infrared wavelength). Therefore, an LED element that primarily emits wavelengths of 400-470 nm (blue wavelength), 640-690 nm (red wavelength), and 710-740 nm (far-infrared wavelength), or a combination of these, is preferable.

[0032] Furthermore, the LED line light source unit 100 for photosynthetic organism artificial cultivation devices shown in Figures 1 to 3 is used under special conditions, unlike general lighting applications. This is the distance from the photosynthetic organisms. For general lighting applications, the ceiling height is approximately 3 meters in offices and 20 meters in factories, and white light must be widely diffused. However, the LED line light source unit 100 for photosynthetic organism artificial cultivation devices of the present invention is used in a different way. First, to improve the yield per unit area of ​​the plant factory, the photosynthetic organism artificial cultivation device is configured in a vertically multi-tiered configuration, and the LED line light source unit 100 for photosynthetic organism artificial cultivation devices is installed on each shelf. The height of each tier is, for example, 100 cm or less. Second, the distance from the photosynthetic organisms is also controlled to be small, and the distance between each LED element (blue LED element 110, red LED element 120, far-infrared LED element 130) using power semiconductors and the leafy plants (photosynthetic organisms) is expected to be 10 cm to 100 cm, a short distance. The light emitted from each LED element using a power semiconductor is emitted at a close distance. In order to suppress wavelength unevenness when emitting light at such a close distance, the arrangement of each LED element using a power semiconductor (blue LED element 110, red LED element 120, far-infrared LED element 130) is dispersed as much as possible to appropriately mix blue wavelength light, red wavelength light, and far-infrared wavelength light and suppress wavelength unevenness.

[0033] 1(a) does not allow detailed illustration of the arrangement of the LED elements, but it is assumed that the ratio of (number of red LED elements 110): (number of blue LED elements 120 + number of far-infrared LED elements 130) in the LED element row 101a is 7:3. Note that this ratio is just an example, and the ratio of (number of red LED elements): (number of blue LED elements + number of far-infrared LED elements) in the LED element row 101a may be in the range of 6:4 to 8:2.

[0034] Next, FIG. 1(b) is an enlarged view of a portion of FIG. 1(a). In the example shown in FIG. 1(b), the arrangement of the LED elements in the dispersed one-dimensional single row LED element array 101a is such that, in at least a portion of the area, two red LED elements 110 are lined up, then one blue LED element 120, then two red LED elements 110, then one far-infrared LED element 120, then three red LED elements 110, then one blue LED element 120, then two red LED elements 110, then one far-infrared LED element 130, then two red LED elements 110, then one blue LED element 120, then three red LED elements 110, then one far-infrared LED element 130. If the arrangement of the LED elements in the one-dimensional row of LED elements 101a is a repeat of the pattern shown in Figure 1(b), the ratio of (number of red LED elements 110):(number of blue LED elements 120 + number of far-infrared LED elements 130) will be 7:3.

[0035] Next, Figure 1(c) is a vertical cross-sectional view enlarged from the A-A line cross-section of Figure 1(b). As shown in Figure 1(c), the red LED elements 110 irradiate a wide area evenly, and the blue LED elements 120 and far-infrared LED elements 130 are also arranged in a scattered manner, but are relatively uniformly distributed. In other words, in the LED line light source unit 100a for photosynthetic organism artificial culture devices according to the configuration of Figure 1, the ratio of the number of LED elements (number of red LED elements 110):(number of blue LED elements 120 + number of far-infrared LED elements 130) is 7:3. As a result, the ratio of wavelength components of the light irradiation is approximately 70% light in the red wavelength band of 640-690 nm, approximately 15% light in the blue wavelength band of 400-470 nm, and approximately 15% light in the far-infrared wavelength band of 710-740 nm. Figure 1(d) is a cross-sectional view taken along line B-B. As shown in FIG. 1( c), the proportion of red LED elements 110 is high at 70%, but 15% of blue LED elements 120 and 15% of far-infrared LED elements 130 are also included, although they are arranged discontinuously. As shown in the cross-sectional view of line B-B, although there is only one LED element, when the light emitted from each LED element adjacent to the depth direction of the drawing is shown overlapping and collected on each cross section, it becomes an appropriate mixture of red wavelength light, blue wavelength light, and far-infrared light.

[0036] Next, we will explain the LED line light source unit 100b for photosynthetic organism artificial culture devices, which is an example of a configuration in which the LED elements are arranged in a two-dimensional, three-row configuration with a distributed configuration, as shown in Figure 2. As shown in Figure 2(a), a large number of LED elements are arranged in three two-dimensional rows, each consisting of a first LED element row 101b1, a second LED element row 101b2, and a third LED element row 101b3. The LED line light source unit 100b for photosynthetic organism artificial culture devices has a distributed configuration in which a large number of red LED elements 110 emitting light in the red wavelength band of 640 to 690 nm, blue LED elements 120 emitting light in the blue wavelength band of 400 to 470 nm, and far-infrared LED elements 130 emitting light in the far-infrared wavelength band of 710 to 740 nm are distributed in three two-dimensional rows. Note that each LED element may be similar to that described in Figure 1. 2(a) does not allow detailed illustration of the arrangement of the LED elements, but the overall two-dimensional three-row configuration of the first LED element row 101b1, the second LED element row 101b2, and the third LED element row 101b3 is assumed to have an example in which the ratio of (number of red LED elements 110):(number of blue LED elements 120 + number of far-infrared LED elements 130) is 7:3. The ratio may be in the range of 6:4 to 8:2.

[0037] 2(b) is an enlarged view of a portion of FIG. 2(a), and in the example shown in FIG. 2(b), in at least a portion of the dispersed two-dimensional three-row arrangement, the central second LED element row 101b2 has 14 red LED elements 110 arranged in rows, the first LED element row 101b1 at the top of the figure has wider spacing between LED elements than the first LED element row 101b but has one blue LED element 120 and one far-infrared LED element 130 arranged alternately, and the third LED element row 101b3 at the bottom of the figure has one far-infrared LED element 130 and one blue LED element 120 arranged alternately. The total number of elements in the first element row 101b1 and the third element row 101b3 is smaller than the number in the second element row 101b2. If the arrangement of the LED elements in the LED line light source unit 100b for the photosynthetic organism artificial culture device is a repeat of the pattern shown in Figure 2(b), the ratio of (number of red LED elements 110): (number of blue LED elements 120 + number of far-infrared LED elements 130) will be 7:3.

[0038] Next, Figure 2(c) is an enlarged longitudinal cross-sectional view taken along line CC in Figure 2(b). Figure 2(d) is an enlarged horizontal cross-sectional view taken along the first LED element row 101b1. As shown in Figure 2(c), the cross-section taken along line B-B is a cut through the second LED element row 101b2, so the red LED elements 110 illuminate a wide area evenly. Figure 2(d) is a cross-sectional view taken along the first LED element row 101b1. As shown in Figure 2(d), the blue LED elements 120 and far-infrared LED elements 130 are also arranged in a discontinuous manner in the first LED element row 101b1, but they are relatively uniformly distributed along the longitudinal axis. Figure 2(e) is an enlarged longitudinal cross-sectional view taken along line D-D in Figure 2(b). Figure 2(f) is an enlarged horizontal cross-sectional view taken along line D-D of the next LED element row. In Figures 2(e) and 2(f), the LED elements are shown superimposed on a vertical cross section to make it easier to understand the relative positions of the LED elements and the light irradiation range. As shown in Figure 2(e), the red LED element 110 is located in the center and irradiates a wide area evenly. The blue LED elements 120 and far-infrared LED elements 130 are also located on the left and right, but are also relatively evenly distributed in the minor axis direction perpendicular to the major axis. Similarly, as shown in Figure 2(f), the arrangement of the blue LED elements 120 and far-infrared LED elements 130 on the left and right of the LED elements in the next row adjacent to line D-D is swapped.

[0039] In other words, in the LED line light source unit 100b for photosynthetic organism artificial culture device having the configuration of Figure 2, the ratio of the number of LED elements (number of red LED elements 110): (number of blue LED elements 120 + number of far-infrared LED elements 130) is 7:3, and as a result, the ratio of the wavelength components of the light irradiation is also composed of approximately 70% light in the red wavelength band of 640 to 690 nm, approximately 15% light in the blue wavelength band of 400 to 470 nm, and approximately 15% light in the far-infrared wavelength band of 710 to 740 nm.

[0040] Next, we will describe the LED line light source unit 100c for photosynthetic organism artificial culture devices. As shown in Figure 3, the LED elements are arranged in a three-dimensional configuration in three rows, with each row having a slightly different height and a different irradiation angle. As shown in Figure 3(a), a large number of LED elements are arranged in three three-dimensional rows, each designated as a first LED element row 101c1, a second LED element row 101c2, and a third LED element row 101c3. The LED line light source unit 100c for photosynthetic organism artificial culture devices has a distributed configuration in which a large number of red LED elements 110 emitting light in the red wavelength band of 640 to 690 nm, blue LED elements 120 emitting light in the blue wavelength band of 400 to 470 nm, and far-infrared LED elements 130 emitting light in the far-infrared wavelength band of 710 to 740 nm are distributed in three three-dimensional rows. Each LED element may be the same as that described with reference to FIG.

[0041] 3(a) does not allow detailed illustration of the arrangement of the LED elements, but the overall three-dimensional configuration of the first LED element row 101c1, the second LED element row 101c2, and the third LED element row 101c3 is assumed to have an example in which the ratio of (number of red LED elements 110):(number of blue LED elements 120 + number of far-infrared LED elements 130) is 7:3. The ratio may be in the range of 6:4 to 8:2.

[0042] Next, Figure 3(b) is an enlarged view of a portion of Figure 3(a). In the example shown in Figure 3(b), in at least a portion of the dispersed three-row three-dimensional arrangement, the central second LED element row 101c2 has 14 red LED elements 110 arranged in a row, and the first LED element row 101c1 at the top of the figure has one blue LED element 120 and one far-infrared LED element 130 arranged alternately. The third LED element row 101c3 at the bottom of the figure has one far-infrared LED element 130 and one blue LED element 120 arranged alternately. The total number of elements in the first element row 101c1 and the third element row 101c3 is smaller than the number in the second element row 101c2. If the arrangement of the LED elements in the LED line light source unit 100c for the photosynthetic organism artificial culture device is a repeat of the pattern shown in Figure 3(b), the ratio of (number of red LED elements 110):(number of blue LED elements 120 + number of far-infrared LED elements 130) will be 7:3.

[0043] Next, Figure 3(c) is an enlarged longitudinal cross-sectional view taken along line E-E in Figure 3(b). Figure 3(d) is an enlarged transverse cross-sectional view taken along the first LED element row 101b1. As shown in Figure 3(c), the red LED elements 110 are irradiated directly downward, irradiating a wide area evenly. Also, as shown in Figure 3(d), the blue LED elements 120 and far-infrared LED elements 130 are also arranged in a discontinuous manner, but are relatively evenly distributed along the longitudinal axis. Figure 3(e) is an enlarged transverse cross-sectional view taken along line F-F. Figure 3(f) is an enlarged transverse cross-sectional view of the next LED element adjacent to line F-F. In Figures 3(e) and 3(f), the LED elements are superimposed on the longitudinal cross-section to clearly show the relative positions and light irradiation ranges of each LED element. As shown in Figures 3(e) and 3(f), the irradiation angles of the blue LED elements 120 and far-infrared LED elements 130 arranged in the first element row 101c1 and the third element row 101c3 are slightly tilted toward the second element row 101c2 in the center, and are adjusted so that the irradiated light is irradiated directly downward rather than being diffused to the left and right.

[0044] 3(e) and 3(f), the illumination angle of the second LED element row 101c2 in the center is set directly downward, but the first LED element row 101c1 on the upper side of the figure is slightly taller than the second LED element row 101c2, its illumination angle is positioned slightly closer to the center, and each blue LED element 120 and each far-infrared LED element 130 are arranged alternately. The third LED element row 101c3 on the lower side of the figure is slightly taller than the second LED element row 101c2, its illumination angle is positioned slightly closer to the center, and each far-infrared LED element 130 and each blue LED element 120 are arranged alternately. This can be said to be a three-dimensional, three-row arrangement of LED elements.

[0045] Thus, in the LED line light source unit 100c for photosynthetic organism artificial culture devices with a three-dimensional three-row distributed arrangement in Figure 3, the ratio of the number of LED elements (number of red LED elements 110): (number of blue LED elements 120 + number of far-infrared LED elements 130) is 7:3. As a result, the ratio of the wavelength components of the light irradiation is approximately 70% light in the red wavelength band of 640 to 690 nm, approximately 15% light in the blue wavelength band of 400 to 470 nm, and approximately 15% light in the far-infrared wavelength band of 710 to 740 nm. In addition, the light irradiation angle and irradiation range are designed to be more uniform compared to the configuration of Figure 2.

[0046] Next, we will describe the innovations in the drive control of the LED elements in LED line light source unit 100 for a photosynthetic organism artificial culture device. LED line light source unit 100 for a photosynthetic organism artificial culture device of the present invention is equipped with a constant current control circuit 140, which controls the drive of the LED elements as shown below. This constant current control circuit 140 can be applied to the one-dimensional single-row LED element array configuration shown in Figure 1, the two-dimensional three-row LED element array configuration shown in Figure 2, and the three-dimensional three-row LED element array configuration shown in Figure 3.

[0047] The constant current control circuit 140 is a circuit that supplies a constant current to each of the red LED elements 110, blue LED elements 120, and far-infrared LED elements 130 in the distributed arrangement, and drives the LED elements to emit light by constant current drive. Here, the value of the constant current supplied from the constant current control circuit 140 is lower than the rated current value, that is, in the range of 1 / 4 to 3 / 4 of the rated current value of each of the red LED elements 110, blue LED elements 120, and far-infrared LED elements 130. Each LED element is driven by supplying this low constant current.

[0048] FIG. 4 is a simplified diagram illustrating an example of driving each LED element using the constant current control circuit 140. The driving principles are the same for the red LED element 110, blue LED element 120, and far-infrared LED element 130, so the example will be described using the red LED element 110 as an example. As shown in FIG. 4, the driving current of the red LED element 110 is I·2 / 3 (amperes), which is lower than the rated current I (amperes). If the resistance of the red LED element 110 is R, the power consumption W (watts) is R·I2 when driven at the rated current. However, since the red LED element 110 is driven at a low current of I·2 / 3 (amperes), the power consumption W becomes W = R·(I·2 / 3)2 = 4 / 9 (RI2), resulting in 4 / 9 of the power consumption. Clearly, a power consumption of 4 / 9 dramatically reduces the power energy consumed. However, in conventional technology, it was common knowledge not to drive LED elements at such a low constant current. This is because LED element manufacturers design LED elements so that they achieve the highest light-emitting efficiency when driven at the rated current I specified for the element. At first glance, it may seem that driving at the rated current is the most rational method of driving, since the conversion efficiency of the amount of light emitted into electrical energy is high, but this is because mass-produced LED elements are expected to be used in homes, offices, factories, etc. as replacements for conventional light sources for lighting purposes, emitting a sufficient amount of light with high efficiency.

[0049] However, the present invention is intended to be used exclusively for artificial lighting in plant factories. Due to the special circumstances of growing photosynthetic organisms directly below and at a short distance, the LED elements do not need to emit as much light. However, in conventional technology, LED elements widely used for general-purpose applications in homes, offices, factories, etc., have been used in consideration of the availability of LED elements on the market, and have been driven at a rated current to maintain high luminous efficiency. However, in the present invention, the LED line light source unit 100 for photosynthetic organism artificial cultivation devices is intended to be used exclusively for artificial lighting in plant factories. Due to the special circumstances of growing photosynthetic organisms directly below and at a short distance, the LED elements are driven at a constant current lower than the rated current.

[0050] In addition, there is a concern that the amount of light emitted by LED elements will decrease if the voltage and current applied to them are lower than the rated voltage and current. Therefore, a solution to this problem is to drive the LED elements at a drive voltage and drive current lower than the rated voltage and current, and increase the number of LED elements to compensate for the decrease in light amount. In other words, in the configurations shown in Figures 1, 2, and 3, the number of LED elements per unit area can be adjusted by adjusting the spacing between the LED elements in the long axis direction in the repeating pattern of the LED element arrangement shown in Figure 1(b), the repeating pattern of the LED element arrangement shown in Figure 2(b), and the repeating pattern of the LED element arrangement shown in Figure 3(b).

[0051] Furthermore, by implementing the above-mentioned constant current drive at a low current, the lifespan of the LED line light source unit can be extended. Since the LED elements deteriorate more as the applied voltage and current become larger, if the lifespan of the LED elements is important, it is more advantageous to drive them at a low voltage and current.

[0052] As described above, if the LED elements are driven at a drive voltage and drive current lower than the rated voltage and rated current, and the number of LED elements is increased to compensate for the resulting decrease in light output, this will result in a disadvantage in that the cost of the LED elements will increase, but in return, this will result in an advantage in that the lifespan of the LED elements will be longer, which can offset the disadvantage.

[0053] Next, as Example 2, a configuration example of a photosynthetic organism artificial culture device 200 incorporating the LED line light source unit 100 for photosynthetic organism artificial culture device as a light source is shown. Figure 5 is a diagram simply showing a configuration example of the photosynthetic organism artificial culture device 200 according to Example 2. The configuration example in Figure 5 is just one example, and many variations are possible.

[0054] As shown in Figure 5, photosynthetic organism artificial culture device 200 according to Example 2 is configured to include LED line light source unit 100 for photosynthetic organism artificial culture device, light source support structure 210, and photosynthetic organism support structure 220. LED line light source unit 100 for photosynthetic organism artificial culture device may be any one of LED line light source units 100a, 100b, and 100c for photosynthetic organism artificial culture device shown in Figures 1, 2, and 3 of Example 1, or a combination thereof.

[0055] The light source support structure 210 is a structure that supports the LED line light source unit for the photosynthetic organism artificial culture device in a predetermined position and orientation. The photosynthetic organism support structure 220 is a structure that supports the photosynthetic organism so that it faces the LED line light source unit for the photosynthetic organism artificial culture device 100. The photosynthetic organisms 300 can be agricultural plants (especially leafy vegetables such as lettuce), ornamental plants, algae, phytoplankton, euglena, chloroplast-containing bacteria, chloroplast-containing microorganisms, chloroplast-containing bacteria, or a combination thereof. The LED elements are mounted so that they emit light of a predetermined wavelength at a predetermined irradiation angle from their placement location. A detailed description of the LED voltage control circuit is omitted; it receives an externally supplied voltage and controls the required current to each LED element.

[0056] The separation distance (H) between the LED line light source unit 100 for a photosynthetic organism artificial culture device supported by the light source support structure 210 shown in Figure 5 and the photosynthetic organisms, such as agricultural plants, supported by the photosynthetic organism support structure 220 can be freely adjusted, but generally a short distance of about several tens of centimeters to 1 meter is sufficient. In other words, a separation distance of about 3 to 5 meters, as required for general indoor or office lighting, is not necessary, and a separation distance of about 5 to 20 meters, as required for general factory lighting, is not necessary. Therefore, the illumination intensity of the LED line light source unit 100 for a photosynthetic organism artificial culture device in the photosynthetic organism artificial culture device 200 may be relatively smaller than the illumination intensity required for such general lighting.

[0057] Next, we will discuss the efficiency of photosynthetic organism cultivation using a photosynthetic organism artificial cultivation device 200 incorporating the LED line light source unit 100 for photosynthetic organism artificial cultivation device of the present invention as a light source. Figure 6(a) is a photograph of the exterior of a prototype LED line light source unit 100 for photosynthetic organism artificial cultivation device. The LED elements are arranged in a one-dimensional row, as shown in Figure 1. Figure 6(b) is a photograph showing the LED line light source unit 100 for photosynthetic organism artificial cultivation device of Figure 6(a) when turned on. Because the ratio of red LED elements is 70%, the overall illumination light has a reddish tint, although this is difficult to see in a monochrome image.

[0058] Figure 7 is a graph comparing the energy distribution of the wavelength of the light irradiated by the prototype LED line light source unit 100 for a photosynthetic organism artificial culture device according to the present invention with the energy distribution of the wavelength of the light irradiated by a general white LED line light source unit used as a control.

[0059] Figure 7(a) shows the spectral distribution of the energy of the irradiated light from the prototype LED line light source unit 100 for a photosynthetic organism artificial culture device according to the present invention. As shown in Figure 7(a), since the red LED elements 110 account for 70% of the total, there is a large energy peak in the red wavelength band of 640 to 690 nm. There are also small energy peaks in the blue wavelength band of 400 to 470 nm from the blue LED elements 120, and small energy peaks in the far-infrared wavelength band of 710 to 740 nm from the far-infrared LED elements 130. In order to prevent the spectral distribution of the energy of such irradiated light from being concentrated in certain areas, the LED elements are dispersed as shown in Figure 1 of Example 1, and the light is irradiated uniformly.

[0060] On the other hand, Figure 7(b) shows the spectral distribution of the energy of the light emitted by a general pseudo-white LED line light source unit used as a control. As shown in Figure 7(b), the general pseudo-white LED line light source unit has some energy peaks, but it can be seen that it gently covers all wavelength bands from around 400 nm to around 740 nm.

[0061] Figure 8 shows the assembled demonstration system of the photosynthetic organism artificial culture device 200. Figure 8(a) shows an example of the configuration of the demonstration system of the photosynthetic organism artificial culture device 200 incorporating the prototype LED line light source unit 100 for the photosynthetic organism artificial culture device of the present invention as a light source. A similar demonstration system configuration to that of Figure 8(a) was also constructed using a general pseudo-white LED line light source unit as a control. Figure 8(b) shows the side-on fixed-point observation of the demonstration system of the photosynthetic organism artificial culture device 200 of the present invention shown in Figure 8(a). As with Figure 7(a), red LED elements 110 account for 70% of the light source, so the overall illumination light is reddish, although this is difficult to see in the monochrome image. Figure 8(c) shows the side-on fixed-point observation of the demonstration system of the pseudo-white LED line light source unit assembled as a control.

[0062] Here, a constant current was supplied to the control (Figure 8(c)) demonstrating a pseudo-white LED line light source unit, with a power supply energy of 23 (W). On the other hand, a constant current lower than the control was supplied to the demonstration system of the photosynthetic organism artificial culture device 200 of the present invention (Figure 8(b)), with a power supply energy of 16 (W / h). In other words, the power supply energy was approximately 70% of the power supplied to the control.

[0063] Figure 9 shows a comparison of the yields of plants grown for a three-week period, from planting on April 18, 2024, to harvest on May 7. The plant species grown was leaf lettuce. Figure 9(a) shows leaf lettuce grown in a demonstration system for the photosynthetic organism artificial culture device 200 of the present invention and its yield (weight). The yield (weight) was 146 g. Figure 9(b) shows leaf lettuce grown in a demonstration system for a pseudo-white LED line light source unit as a control and its yield (weight). The yield (weight) was 116 g.

[0064] Comparing the two, the yield was approximately 25% higher in the demonstration system for the photosynthetic organism artificial cultivation device 200 of the present invention than in the demonstration system for the pseudo-white LED line light source unit used as a control. Furthermore, when the energy conversion yield was calculated and compared taking into account the difference in the power energy supplied as a constant current, it can be estimated that the yield was approximately 80% higher in the demonstration system for the photosynthetic organism artificial cultivation device 200 of the present invention than in the demonstration system for the pseudo-white LED line light source unit used as a control.

[0065] To improve the accuracy of the verification, similar experiments were repeated. Figure 10 shows a comparison of the yields of plants grown for three weeks, from planting on May 2, 2024, until harvest on May 23. The plant species grown was also leaf lettuce. Figure 10(a) shows leaf lettuce grown in a demonstration system for the photosynthetic organism artificial culture device 200 of the present invention and its yield (weight). The yield (weight) was 129 g. Figure 10(b) shows leaf lettuce grown in a demonstration system using a pseudo-white LED line light source unit as a control and its yield (weight). The yield (weight) was 97 g.

[0066] Comparing the two, the yield was approximately 32% higher in the demonstration system for the photosynthetic organism artificial cultivation device 200 of the present invention than in the demonstration system for the pseudo-white LED line light source unit used as a control. Furthermore, when the energy conversion yield was calculated and compared taking into account the difference in the power energy supplied as a constant current, it can be evaluated that the yield was approximately 90% higher in the demonstration system for the photosynthetic organism artificial cultivation device 200 of the present invention than in the demonstration system for the pseudo-white LED line light source unit used as a control.

[0067] The above demonstration experiment was an experiment using the one-dimensional single-row LED line light source unit 100a for photosynthetic organism artificial culture device of the present invention shown in FIG. 1. However, if the two-dimensional three-row LED line light source unit 100b for photosynthetic organism artificial culture device of the present invention shown in FIG. 2 or the two-dimensional three-row LED line light source unit 100c for photosynthetic organism artificial culture device of the present invention shown in FIG. 3 is used, the three wavelength bands of light necessary for photosynthesis, that is, irradiation light in the red wavelength band of 640 to 690 nm, irradiation light in the blue wavelength band of 400 to 470 nm, and irradiation light in the far-infrared wavelength band of 710 to 740 nm, are supplied more uniformly, further improving the energy conversion yield of photosynthetic plants.

[0068] As described above, the LED line light source unit 100 for a photosynthetic organism artificial culture device of the present invention and the photosynthetic organism artificial culture device 200 using the same of the present invention can achieve a large energy conversion yield of photosynthetic plants.

[0069] The above has illustrated and explained preferred embodiments of the present invention, but the photosynthetic organisms of the present invention are not particularly limited, and the present invention can be widely applied to artificial cultivation devices for photosynthetic organisms such as agricultural crops, fruit vegetables, herbs, carbohydrate-producing organisms, and biofuel-producing organisms, as well as artificial lighting devices for such organisms.

[0070] 100 LED line light source unit for photosynthetic organism artificial culture device 110 Red LED element 120 Blue LED element 130 Far-infrared LED element 140 Constant current control circuit 200 Photosynthetic organism artificial culture device

Claims

1. An LED line light source unit for a photosynthetic organism artificial cultivation device, which is arranged with a large number of LED elements for use in a device for artificially culturing photosynthetic organisms, wherein the LED elements are LED elements using power semiconductors, the rated current value of the LED elements is 350 mA or more, and the arrangement of the LED elements in the LED line light source unit for a photosynthetic organism artificial cultivation device is a dispersed arrangement in which red LED elements that emit light in the red wavelength band of 640 to 690 nm, blue LED elements that emit light in the blue wavelength band of 400 to 470 nm, and far-infrared LED elements that emit light in the far-infrared wavelength band of 710 to 740 nm are dispersed.

2. The LED line light source unit for a photosynthetic organism artificial culture device described in claim 1, characterized in that the photosynthetic organism is a leafy plant, the LED line light source unit for the photosynthetic organism artificial culture device is used on each shelf of a vertically multi-tiered configuration, each tier having a height of 100 cm or less, the distance between the LED element using the power semiconductor and the leafy plant is a short distance of 0 cm to 100 cm, and the light emitted from the LED element using the power semiconductor is irradiated at the short distance.

3. The LED line light source unit for a photosynthetic organism artificial culture device according to claim 2, characterized in that in the dispersed arrangement of the LED elements of the LED line light source unit for a photosynthetic organism artificial culture device, the following conditions 1 and 2 are satisfied: Condition 1 (the illuminance of the red LED elements):(the illuminance of the blue LED elements) ratio is in the range of 6:4 to 8:2, and Condition 2 (the illuminance of the red LED elements):(the illuminance of the far-infrared LED elements) ratio is in the range of 6:4 to 8:

2. Note that the unit of illuminance is PDF (μmol / m2s).

4. An LED line light source unit for a photosynthetic organism artificial culture device as described in any one of claims 1 to 3, characterized in that the distributed arrangement is a one-dimensional row in the longitudinal direction, which is the arrangement direction of the LED elements in the LED line light source unit for a photosynthetic organism artificial culture device, and at least a part of it is arranged in such a way that one to several red LED elements are lined up, then one to several blue LED elements are lined up, then one to several red LED elements are lined up, then one to several far-infrared LED elements are lined up.

5. An LED line light source unit for a photosynthetic organism artificial culture device as described in any one of claims 1 to 3, characterized in that the dispersed arrangement is two-dimensional and three rows in the longitudinal direction, which is the arrangement direction of the LED elements in the LED line light source unit for a photosynthetic organism artificial culture device, with a first row of LED elements, a second row of LED elements, and a third row of LED elements along the longitudinal direction, the second row of LED elements being the row in which the red LED elements are arranged, and the blue LED elements and the far-infrared LED elements being arranged in the first row of LED elements and the third row of LED elements, respectively, and being arranged alternately on either side of the second row of LED elements.

6. An LED line light source unit for a photosynthetic organism artificial culture device as described in any one of claims 1 to 3, characterized in that the dispersed arrangement is a three-dimensional arrangement in three rows in the long axis direction, which is the arrangement direction of the LED elements in the LED line light source unit for a photosynthetic organism artificial culture device, with a first row of LED elements, a second row of LED elements, and a third row of LED elements along the long axis direction, the first row of LED elements, the second row of LED elements, and the third row of LED elements each have different heights and orientation angles, the second row of LED elements is the row in which the red LED elements are arranged, the blue LED elements and the far-infrared LED elements are arranged in the first row of LED elements and the third row of LED elements, respectively, and are arranged alternately on either side of the second row of LED elements.

7. The LED line light source unit for a photosynthetic organism artificial culture device according to claim 4, wherein in the LED element package containing the blue LED element, the red LED element, and the far-infrared LED element, the material of the substrate on which each of the LED elements is mounted is a ceramic-based material or a metallic material, and the following conditions 1 and 2 are satisfied: Condition 1: The thermal conductivity of the LED element package is 20 W / m·k or more (W is a unit expressing the power of heat transfer, m is the thickness in the direction of heat conduction, and k is the thermal conductivity); and Condition 2: The current supplied to the LED element package is in the range of 1 / 4 to 3 / 4 of the rated current value of each of the LED elements.

8. The LED line light source unit for a photosynthetic organism artificial culture device according to claim 5, wherein in the LED element package containing the blue LED element, the red LED element, and the far-infrared LED element, the material of the substrate on which each of the LED elements is mounted is a ceramic-based material or a metallic material, and the following conditions 1 and 2 are satisfied: Condition 1: The thermal conductivity of the LED element package is 20 W / m·k or more (W is a unit expressing the power of heat transfer, m is the thickness in the direction of heat conduction, and k is the thermal conductivity); and Condition 2: The current supplied to the LED element package is in the range of 1 / 4 to 3 / 4 of the rated current value of each of the LED elements.

9. The LED line light source unit for a photosynthetic organism artificial culture device according to claim 6, wherein in the LED element package containing the blue LED element, the red LED element, and the far-infrared LED element, the material of the substrate on which each of the LED elements is mounted is a ceramic-based material or a metallic material, and the following conditions 1 and 2 are satisfied: Condition 1: The thermal conductivity of the LED element package is 20 W / m·k or more (W is a unit representing the power of heat transfer, m is the thickness in the direction of heat conduction, and k is the thermal conductivity); and Condition 2: The current supplied to the LED element package is in the range of 1 / 4 to 3 / 4 of the rated current value of each of the LED elements.

10. A photosynthetic organism artificial culture device comprising: an LED line light source unit for a photosynthetic organism artificial culture device as described in claim 7; a light source support structure that supports the LED line light source unit for a photosynthetic organism artificial culture device in a predetermined position and a predetermined posture; and a photosynthetic organism support structure that supports the photosynthetic organism so that it faces the LED line light source unit for a photosynthetic organism artificial culture device.

11. A photosynthetic organism artificial culture device comprising: an LED line light source unit for a photosynthetic organism artificial culture device as described in claim 8; a light source support structure that supports the LED line light source unit for a photosynthetic organism artificial culture device in a predetermined position and a predetermined posture; and a photosynthetic organism support structure that supports the photosynthetic organism so that it faces the LED line light source unit for a photosynthetic organism artificial culture device.

12. A photosynthetic organism artificial culture device comprising: an LED line light source unit for a photosynthetic organism artificial culture device as described in claim 9; a light source support structure that supports the LED line light source unit for a photosynthetic organism artificial culture device in a predetermined position and a predetermined posture; and a photosynthetic organism support structure that supports the photosynthetic organism so that it faces the LED line light source unit for a photosynthetic organism artificial culture device.

Images