LED sheet, LED sheet assembly, and culture system

Abstract

An LED sheet (20) is provided with: a substrate (31) having a first surface (31a) and a second surface (31b) positioned on the opposite side of the first surface (31a); a metal wiring part (32) located on the first surface (31a) of the substrate (31); a plurality of LED chips (21) mounted on the metal wiring part (32); a power receiving terminal (61) that is connected to the metal wiring section (32) and receives power when connected to another LED sheet (20); and a power supply terminal (62) that is connected to the metal wiring section (32) and that supplies power when connected to another LED sheet (20).

Description

Technical Field

[0001] The present disclosure relates to an LED sheet, an LED sheet assembly, and a cultivation system. Background Art

[0002] In recent years, algal biofuels have attracted attention as a renewable energy resource. Algae cultivation methods include open tanks (so-called open systems) and closed photobioreactors (so-called closed systems). Compared to open tanks, closed photobioreactors can minimize contamination of the culture fluid. Furthermore, closed photobioreactors can be operated indoors year-round, resulting in superior algae productivity. Technologies related to algae cultivation using such photobioreactors include, for example, a technique for guiding light from light-emitting diodes to culture tanks using optical waveguides (see, for example, Patent Document 1).

[0003] Furthermore, in recent years, demand has been growing for lighting devices that use low-power LEDs as light sources, replacing conventional fluorescent lamps and high-pressure sodium lamps. An example of a lighting device using LEDs as a light source is an LED lighting device for animal and plant cultivation that utilizes a planar light source formed by arranging multiple LED chips on a flexible circuit board (see, for example, Patent Document 2).

[0004] However, in algae cultivation systems or animal and plant cultivation plants, such LED lighting devices can be used in a connected state by connecting the circuit boards of multiple LED lighting devices. As a technique for connecting circuit boards, a technique is known in which a flexible circuit, which is electrically connected by contacting a connection pad with a connector terminal, is insulated from the terminal end inserted into the connector (for example, see Patent Document 3).

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2012-183002

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 2013-251230

[0009] Patent Document 3: Japanese Patent Application Laid-Open No. 6-6003

[0010] The present disclosure provides an LED sheet, an LED sheet assembly, and a cultivation system that can easily connect LED sheets to each other. Summary of the Invention

[0011] The first embodiment of the present invention is an LED sheet comprising: a substrate having a first surface and a second surface located on the opposite side of the first surface; a metal wiring portion located on the first surface of the substrate; a plurality of LED chips mounted on the metal wiring portion; a power receiving terminal connected to the metal wiring portion and used for receiving power when connected to other LED sheets; and a power supply terminal connected to the metal wiring portion and used for supplying power when connected to other LED sheets.

[0012] Regarding a second aspect of the present disclosure, in the LED sheet of the first aspect, the LED sheet may further include power supply wiring that connects the metal wiring portion to the power receiving terminal and the power supply terminal.

[0013] Regarding a third aspect of the present disclosure, in the LED sheet of the second aspect, the thickness of the power supply wiring may be 18 μm to 100 μm, and the line width of the power supply wiring may be 5 mm to 30 mm.

[0014] Regarding a fourth aspect of the present disclosure, in the LED sheet of each of the first to third aspects, the power receiving terminals and the power supply terminals may be conductors, and at least a portion of the power receiving terminals and at least a portion of the power supply terminals may be exposed.

[0015] According to a fifth aspect of the present disclosure, in the LED sheet according to any of the first to fourth aspects, the power receiving terminals and the power supply terminals can be folded back toward the first surface side or the second surface side.

[0016] Regarding a sixth aspect of the present disclosure, in the LED sheet according to each of the first to fifth aspects, the substrate may include a protrusion protruding outward, and at least one of the power receiving terminal and the power supply terminal may be formed on the protrusion.

[0017] Regarding the seventh aspect of the present disclosure, in each of the LED sheets of the first to sixth aspects, the LED sheet may be provided with a display portion that displays an ON state and an OFF state of the LED chip.

[0018] According to an eighth aspect of the present disclosure, in the LED sheet according to each of the first to seventh aspects, the substrate may be flexible.

[0019] Regarding the ninth embodiment of the present disclosure, in each of the LED sheets of the first embodiment to the eighth embodiment, the planar shape of the substrate can be a k-gon, wherein k is a natural number greater than 3, and the power supply terminals can be provided in plurality, or the power supply terminals can be provided at positions corresponding to at least two of the k sides of the k-gon.

[0020] Regarding the tenth aspect of the present disclosure, in the LED sheet of the ninth aspect, the number of power supply terminals may be k-1 or less, and each of the power supply terminals may be provided at a position corresponding to a different side among the k sides of the k-gon.

[0021] The eleventh embodiment of the present disclosure is an LED sheet assembly, which comprises: a first LED sheet; and a second LED sheet connected to the first LED sheet, the first LED sheet and the second LED sheet being LED sheets of any one of the first to tenth embodiments, respectively, and the power supply terminal of the first LED sheet being connected to the power receiving terminal of the second LED sheet.

[0022] Regarding a twelfth aspect of the present disclosure, in the LED sheet assembly of the eleventh aspect, the power supply terminals of the first LED sheet and the power receiving terminals of the second LED sheet are connected in parallel.

[0023] Regarding the thirteenth embodiment of the present disclosure, in the LED sheet assembly of the above-mentioned eleventh embodiment or the above-mentioned twelfth embodiment, it can also be that the LED sheet assembly further has a connecting component installed on the first LED sheet and the second LED sheet, and the power supply terminal of the first LED sheet and the power receiving terminal of the second LED sheet are connected to each other by means of the connecting component.

[0024] Regarding the fourteenth embodiment of the present disclosure, in each of the LED sheet assemblies of the eleventh embodiment to the thirteenth embodiment, the LED sheet assembly may further include a connecting component installed on the first LED sheet and the second LED sheet, and the second LED sheet may be connected to the first LED sheet by means of the connecting component.

[0025] A fifteenth aspect of the present disclosure is the LED sheet assembly according to each of the eleventh to fourteenth aspects, wherein the LED sheet assembly is foldable.

[0026] Regarding a sixteenth aspect of the present disclosure, in the LED sheet assembly according to each of the eleventh to fifteenth aspects, the power receiving terminal and the power supply terminal are covered with an insulator.

[0027] A seventeenth aspect of the present disclosure is a cultivation system comprising: a culture tube for cultivating algae; and the LED sheet assembly according to any one of the eleventh to sixteenth aspects, which covers an outer surface of the culture tube.

[0028] According to this embodiment, the LED sheets can be easily connected to each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a perspective view showing a culture system according to one embodiment.

[0030] Figure 2 This is a vertical cross-sectional view showing a culture system according to one embodiment.

[0031] Figure 3 This is a schematic diagram showing an LED sheet assembly of a culture system according to one embodiment.

[0032] Figure 4 This is a plan view showing an LED sheet of a culture system according to one embodiment.

[0033] Figure 5A This is a plan view showing a modified example of the LED sheet of the culture system.

[0034] Figure 5B This is a plan view showing a modified example of the LED sheet of the culture system.

[0035] Figure 6A This is a graph showing the relationship between time and voltage when a DC constant voltage is applied to the LED sheet from the control unit.

[0036] Figure 6B This is a graph showing the relationship between time and voltage when a pulse is applied to an LED sheet as a comparative example.

[0037] Figure 7 This is a cross-sectional view showing an LED sheet of a culture system according to one embodiment ( Figure 4 VII-VII line cross-sectional view).

[0038] Figure 8 This is a cross-sectional view showing an LED sheet of a culture system according to one embodiment ( Figure 3 VIII-VIII line sectional view).

[0039] Figure 9 This is a development view showing an LED sheet assembly according to one embodiment.

[0040] Figure 10 This is a cross-sectional view showing an LED sheet assembly according to one embodiment ( Figure 9XX line cross-sectional view).

[0041] Figure 11 This is a cross-sectional view showing an LED sheet assembly according to one embodiment (with Figure 10 corresponding cross-sectional view).

[0042] Figure 12 This is a plan view showing an adhesive member of a culture system according to one embodiment.

[0043] Figure 13A This is a cross-sectional view illustrating a method for manufacturing an LED sheet in a culture system according to one embodiment.

[0044] Figure 13B This is a cross-sectional view illustrating a method for manufacturing an LED sheet in a culture system according to one embodiment.

[0045] Figure 13C This is a cross-sectional view illustrating a method for manufacturing an LED sheet in a culture system according to one embodiment.

[0046] Figure 13D This is a cross-sectional view illustrating a method for manufacturing an LED sheet in a culture system according to one embodiment.

[0047] Figure 13E This is a cross-sectional view illustrating a method for manufacturing an LED sheet in a culture system according to one embodiment.

[0048] Figure 13F This is a cross-sectional view illustrating a method for manufacturing an LED sheet in a culture system according to one embodiment.

[0049] Figure 13G This is a cross-sectional view illustrating a method for manufacturing an LED sheet in a culture system according to one embodiment.

[0050] Figure 13H This is a cross-sectional view illustrating a method for manufacturing an LED sheet in a culture system according to one embodiment.

[0051] Figure 14 This is a schematic perspective view showing an example of use of the culture system according to one embodiment.

[0052] Figure 15 This is a schematic perspective view showing an example of use of the culture system according to one embodiment.

[0053] Figure 16 This is a schematic diagram showing a first modified example of the LED sheet assembly according to one embodiment.

[0054] Figure 17 This is a schematic diagram showing a second modified example of the LED sheet assembly according to one embodiment.

[0055] Figure 18 is a cross-sectional view showing a second modified example of the LED sheet assembly according to one embodiment ( Figure 17 (sectional view along line XVIII-XVIII).

[0056] Figure 19 This is a schematic development view showing a third modified example of the LED sheet assembly according to one embodiment.

[0057] Figure 20A This is a schematic perspective view showing another example of the third modified example of the LED sheet assembly according to one embodiment.

[0058] Figure 20B This is a schematic perspective view showing another example of the third modified example of the LED sheet assembly according to one embodiment.

[0059] Figure 20C This is a schematic perspective view showing another example of the third modified example of the LED sheet assembly according to one embodiment.

[0060] Figure 20D This is a schematic perspective view showing another example of the third modified example of the LED sheet assembly according to one embodiment.

[0061] Figure 20E This is a schematic perspective view showing another example of the third modified example of the LED sheet assembly according to one embodiment.

[0062] Figure 20F This is a schematic perspective view showing another example of the third modified example of the LED sheet assembly according to one embodiment.

[0063] Figure 21 This is a schematic diagram showing another example of the third modified example of the LED sheet assembly according to one embodiment.

[0064] Figure 22 This is a schematic diagram showing another example of the third modified example of the LED sheet assembly according to one embodiment.

[0065] Figure 23 1 is a cross-sectional view showing a fourth modified example of the LED sheet assembly according to one embodiment (with Figure 18 corresponding cross-sectional view).

[0066] Figure 24 This is a perspective view showing a culture system including a fifth modified example of the LED sheet assembly according to one embodiment.

[0067] Figure 25A Schematic perspective views showing a method of folding an LED sheet assembly according to one embodiment and various modifications.

[0068] Figure 25B This is a schematic perspective view showing another example of a folding method of the LED sheet assembly according to one embodiment and each modified example.

[0069] Figure 25C This is a schematic perspective view showing another example of a folding method of the LED sheet assembly according to one embodiment and each modified example.

[0070] Figure 25D This is a schematic perspective view showing another example of a folding method of the LED sheet assembly according to one embodiment and each modified example.

[0071] Figure 25E This is a schematic perspective view showing another example of a folding method of the LED sheet assembly according to one embodiment and each modified example.

[0072] Figure 25F This is a schematic perspective view showing another example of a folding method of the LED sheet assembly according to one embodiment and each modified example. DETAILED DESCRIPTION

[0073] Hereinafter, an embodiment will be described in detail with reference to the accompanying drawings. The figures shown below are schematically shown. Therefore, for ease of understanding, the size and shape of each part are appropriately exaggerated. In addition, it can be implemented with appropriate changes within the scope of the technical idea. In addition, in the figures shown below, the same parts are marked with the same reference numerals, and sometimes a detailed description of a part is omitted. In addition, the numerical values and material names of the dimensions and other components described in this specification are examples of implementation, and are not limited to this, and can be appropriately selected for use. In this specification, terms for determining shape or geometric conditions, such as parallel, orthogonal, vertical, etc., in addition to the strict meaning, are also interpreted to include substantially the same state. It should be noted that in this specification, "upper" and "lower" refer to the state in which the culture tube is upright ( Figure 1 and Figure 2 ) above and below.

[0074] (Cultivation System)

[0075] like Figure 1 and Figure 2 As shown, the cultivation system 1 includes a culture tube 10 for cultivating algae and an LED sheet assembly 20A covering the outer surface of the culture tube 10. The LED sheet assembly 20A includes a plurality of LED sheets 20. A control unit 40 is electrically connected to one of the plurality of LED sheets 20.

[0076] The culture tube 10 includes a hollow main body 11, a bottom 12 provided below the main body 11, and a lid 13 provided above the main body 11. The main body 11 has a cylindrical shape. Alternatively, the main body 11 may have a polygonal cylindrical shape, such as a quadrilateral or octagonal cylindrical shape.

[0077] The bottom portion 12 is circular in plan view and is connected to the lower end of the main body 11. The bottom portion 12 may be integrally formed with the main body 11 or may be detachably mounted to the main body 11. The bottom portion 12 may also have a polygonal shape such as an elliptical or quadrilateral shape in plan view.

[0078] The cover 13 is circular in plan view and is connected to the upper end of the main body 11. The cover 13 can be detachably mounted on the main body 11. The planar shape of the cover 13 can also be a polygonal shape such as an ellipse or a quadrilateral.

[0079] The culture tube 10 is filled with a culture solution CS. As a material constituting the culture tube 10, for example, glass (refractive index: about 1.55), polycarbonate (refractive index: about 1.58), or a resin material such as acrylic acid can be used.

[0080] Next, the LED chip assembly 20A will be described in detail. As described above, the LED chip assembly 20A includes a plurality of LED chips 20. In the example shown in the figure, the LED chip assembly 20A includes a first LED chip 201, a second LED chip 202, and a third LED chip 203 (see FIG. 2 ). Figure 1 and Figure 2 ). The second LED chip 202 is connected to the first LED chip 201. In addition, the third LED chip 203 is connected to the second LED chip 202. In this embodiment, the plurality of LED chips 20 (the first LED chip 201, the second LED chip 202 and the third LED chip 203) are arranged along the first arrangement direction of the LED chips 21 (X direction, refer to Figure 3 and Figure 9 ) configuration. The LED sheet assembly 20A can also be folded as described later. In this specification, the first LED sheet 201, the second LED sheet 202, or the third LED sheet 203 is also referred to as the LED sheet 20. Furthermore, the LED sheet assembly 20A may include four or more LED sheets 20.

[0081] In addition, the LED chip assembly 20A also has a connecting component 26. In the example shown in the figure, the LED chip assembly 20A has a plurality of (two) connecting components 26. In addition, the number of connecting components 26 is not limited to this. For example, although not shown in the figure, the LED chip assembly 20A may also have only one connecting component 26, or the LED chip assembly 20A may also have three or more connecting components 26. In this embodiment, one of the two connecting components 26 is detachably mounted on the first LED chip 201 and the second LED chip 202. Furthermore, the second LED chip 202 is connected to the first LED chip 201 via the connecting component 26. In addition, the other connecting component 26 is detachably mounted on the second LED chip 202 and the third LED chip 203. Furthermore, the third LED chip 203 is connected to the second LED chip 202 via the connecting component 26. In addition, the connecting component 26 may also be mounted on the first LED chip 201, etc. in a non-detachable manner.

[0082] The connecting component 26 may be, for example, a double-sided tape or a tape such as Velcro, an adhesive, or a rivet. In addition, the connecting component 26 may also be a rope-shaped component such as an insulating lock. In the case where the connecting component 26 is a rope-shaped component, for example, a through hole (not shown) that passes through the LED sheet 20 may be formed in the LED sheet 20, and the connecting component 26 may be passed through the through hole, thereby connecting the LED sheets 20 to each other. In this case, a metal ring (not shown) may also be used to protect the periphery of the through hole. In addition, in the example shown in the figure, the connecting component 26 connects the LED sheets 20 to each other from the side of the LED sheet 20 opposite to the light-emitting surface 20a, but is not limited to this. The connecting component 26 may also connect the LED sheets 20 to each other from the light-emitting surface 20a side of the LED sheet 20, or may connect the LED sheets 20 to each other from the light-emitting surface 20a side of the LED sheet 20 and the side opposite to the light-emitting surface 20a.

[0083] The LED sheet assembly 20A is wound around the culture tube 10 in such a manner that the light-emitting surface 20a of each LED sheet 20 faces the culture tube 10. The LED sheet 20 covers the main body 11 of the culture tube 10. The LED sheet 20 preferably covers the entire area of the main body 11 of the culture tube 10 in the circumferential direction of the main body 11. Thus, light can be irradiated into the culture tube 10 from the entire circumference of the main body 11. Therefore, the cultivation efficiency of algae can be improved. In addition, the LED sheet 20 preferably covers the entire area of the main body 11 of the culture tube 10 in the longitudinal direction. Thus, the utilization efficiency of light can be further improved.

[0084] Here, a display portion 25 may also be provided on the LED sheet 20, wherein the display portion 25 displays the ON (on) state of the LED chip 21 and the OFF (off) state of the LED chip 21 described later. Thus, even when the LED sheet 20 is wound around the culture tube 10, the ON state and the OFF state of the LED chip 21 can be easily confirmed. In the present embodiment, the display portion 25 is a through hole that passes through the LED sheet 20. In this case, when the LED chip 21 is lit, light leaks slightly from the display portion 25. On the other hand, when the LED chip 21 is not lit, light does not leak from the display portion 25. In this way, the ON state and the OFF state of the LED chip 21 can be easily confirmed.

[0085] Furthermore, when forming the display portion 25, it is also possible not to form a through hole in the LED sheet 20, but to leave only the substrate 31 described later. In this case, since the substrate 31 is transparent, the ON and OFF states of the LED chip 21 can also be easily confirmed. In addition, in the example shown in the figure, the shape of the through hole is rectangular when viewed from the front, but the size and shape of the through hole are not particularly limited. In addition, a plurality of through holes can also be formed. For example, a through hole can be formed near each LED chip 21. In this way, it is easy to identify the LED chip 21 that has been damaged.

[0086] like Figure 3 and Figure 4 As shown, the LED sheet 20 is a planar light source sheet with so-called single-sided light emission. Multiple LED chips 21 are arranged on the light-emitting surface 20a of the LED sheet 20. By using this direct-lit LED sheet 20, the light from the LED chips 21 passes directly through the light-emitting surface 20a. This increases the amount of light emitted, thereby promoting algae cultivation. Furthermore, compared to LED strip lights, the LED sheet 20 can be made thinner overall, thus preventing shadows from forming on the sides of the LED chips 21.

[0087] Figure 4 The LED sheet 20 includes a flexible wiring substrate 30, a plurality of LED chips 21 mounted on a metal wiring portion 32 described later of the flexible wiring substrate 30, a power receiving terminal 61, and a power supply terminal 62. By using such a flexible wiring substrate 30, an LED sheet 20 having a relatively large sheet surface area can be obtained. An LED sheet 20 having a relatively large sheet surface area can reduce the number of LED sheets 20 used, thereby suppressing deviations in light intensity that may occur due to the configuration of multiple LED sheets 20. The LED sheet 20 having a relatively large sheet surface area can also be, for example, about 600 mm × 500 mm in size. In addition, in Figure 4In the figure, the light-reflective insulating protective film 34 and the transparent protective film 35 described later are omitted.

[0088] In this case, the LED chips 21 are regularly arranged on the flexible wiring substrate 30. Specifically, when viewed from above, the LED chips 21 are arranged in a lattice pattern within the flexible wiring substrate 30. That is, the LED chips 21 are arranged in a matrix in multiple stages and columns, with N columns of M LED chips 21 connected in series.

[0089] For example, Figure 4 , 14 (M=14) LED chips 21 are connected in series along the first arrangement direction (X direction) of the LED chips 21. Furthermore, the column R having the 14 LED chips 21 is arranged in 10 columns (N=10) in parallel along the second arrangement direction (Y direction) of the LED chips 21. In addition, the number of LED chips 21 to be arranged is not limited to this. Specifically, with respect to the LED chips 21, more than 6 (M≥6) LED chips 21 can be arranged in series in the first arrangement direction (X direction), or more than 10 (M≥10) LED chips 21 can be arranged in series. In addition, less than 14 (14≥M) LED chips 21 can be arranged in series in the first arrangement direction (X direction), or less than 12 (12≥M) LED chips 21 can be arranged in series. In addition, the column R can also be arranged in 4 or more columns (N≥4) in parallel in the second arrangement direction (Y direction) of the LED chips 21, preferably 6 or more (N≥6) LED chips can be arranged in parallel. Furthermore, the column R can also be arranged in parallel in 10 or less columns (10 ≥ N) in the second arrangement direction (Y direction) of the LED chips 21, preferably in 8 or less columns (8 ≥ N). By arranging more than 10 LED chips 21 in series, the intervals between the LED chips 21 in the first arrangement direction (X direction) can be shortened. Thus, the in-plane deviation of the illumination of the LED sheet 20 can be suppressed. Therefore, the deviation of the light irradiated to the culture tube 10 can be suppressed. In addition, by arranging 14 or less LED chips 21 in series, power consumption can be reduced. In addition, for the columns of LED chips 21, more than 4 columns are arranged in parallel in the second arrangement direction (Y direction) of the LED chips 21. Thus, even if a specific LED chip 21 is damaged, it can not affect the LED chips 21 in other columns. Thus, the extreme reduction of the illumination of the entire LED sheet 20 can be suppressed. However, in the case where the LED sheet 20 is a direct-down type, the possibility of the operator coming into contact with the LED chip 21 when setting or removing the LED sheet 20 increases. Furthermore, if a worker accidentally touches an LED chip 21 with force, the likelihood of damage increases. Therefore, it is important from a risk management perspective to implement measures to prevent damage to the LED chip 21. Furthermore, by arranging the rows of LED chips 21 in a row of 10 or fewer, power consumption can be reduced.

[0090] The LED sheet 20 includes a plurality of metal wiring portions 22. The plurality of metal wiring portions 22 are arranged along a first arrangement direction (X direction). The plurality of metal wiring portions 22 arranged along the first arrangement direction (X direction) correspond to respective columns R of the LED chips 21. The LED chips 21 are arranged so as to straddle a pair of metal wiring portions 22 adjacent to each other in the X direction. In addition, each terminal (not shown) of the LED chip 21 is electrically connected to a pair of metal wiring portions 22. The plurality of metal wiring portions 22 constitute a power supply portion for supplying power to the LED chips 21. By supplying power to the plurality of metal wiring portions 22, all the LED chips 21 arranged in the column R are lit. In addition, the plurality of metal wiring portions 22 constitute a part of the metal wiring portion 32 described later.

[0091] The spacing Px between the LED chips 21 in the first arrangement direction (X direction) can be greater than 15 mm, and is preferably set to greater than 25 mm. In addition, the spacing Px between the LED chips 21 can be less than 100 mm, and is preferably less than 60 mm. In addition, the spacing Py between the LED chips 21 in the second arrangement direction (Y direction) can be greater than 15 mm, and is preferably greater than 25 mm. In addition, the spacing Py between the LED chips 21 can be less than 100 mm, and is preferably less than 75 mm. By setting the spacing between the LED chips 21 to the above range, the brightness of the LED sheet 20 can be made uniform within the surface. Therefore, the deviation of the light irradiated into the space can be suppressed, and the power consumption of the LED sheet 20 can be suppressed.

[0092] The thickest portion of the LED sheet 20 is preferably 5 mm or less. By reducing the thickness of the LED sheet 20 in this manner, the increase in volume of the LED sheet 20 can be suppressed when the LED sheet 20 is installed in the culture tube 10. This makes it easy to install the LED sheet 20 in the culture tube 10 even in limited space.

[0093] The arrangement of the LED chips 21 is not limited to the lattice point shape when viewed from above, such as Figure 5A As shown, the LED chips 21 may be arranged in a staggered pattern when viewed from above. In addition, the LED chips 21 may not be arranged uniformly within the surface of the LED sheet 20. For example, the density of the LED chips 21 may be further increased at the periphery of the LED sheet 20. Specifically, as shown in FIG. Figure 5B As shown, it is also possible to have the LED sheet 20 have a central portion ( Figure 5B The LED chips 21 are arranged in a grid pattern, and the peripheral portion of the LED sheet 20 ( Figure 5BThe LED chips 21 are arranged in a staggered pattern. This can suppress the reduction in brightness of the LED sheet 20 at the peripheral portion of the LED sheet 20, make the brightness of the LED sheet 20 uniform within the surface, and suppress the deviation of the light irradiated into the space.

[0094] The overall shape of the LED sheet 20 is rectangular when viewed from above, but the size and planar shape of the LED sheet 20 are not particularly limited. The high degree of freedom in manipulating the size and shape of the LED sheet 20 allows for flexible response to various requirements. Furthermore, the LED sheet 20 is flexible, so it is not limited to flat installation surfaces; it can be installed on surfaces of various shapes.

[0095] exist Figure 4 In the embodiment, the length Lx of the LED sheet 20 in the first arrangement direction (X direction) is preferably 500 mm or more, more preferably 550 mm or more. In addition, the length Lx of the LED sheet 20 in the first arrangement direction (X direction) is preferably 750 mm or less, more preferably 650 mm or less. The length Ly of the LED sheet 20 in the second arrangement direction (Y direction) is preferably 300 mm or more, more preferably 350 mm or more. In addition, the length Ly of the LED sheet 20 in the second arrangement direction (Y direction) is preferably 500 mm or less, more preferably 450 mm or less. By making the size of each LED sheet 20 not too small, the amount of light from the LED sheet 20 can be increased. In addition, by making the size of each LED sheet 20 not too large, in the event that a specific LED chip 21 is damaged, the impact on other LED chips 21 can be minimized. Therefore, it is possible to prevent the overall illumination of the LED sheet 20 from being extremely reduced, and the range of the illumination reduction can be limited.

[0096] Next, the control unit 40 will be described. Figure 3 As shown, the control unit 40 supplies power to the LED sheet 20 and controls the light emission of the LED sheet 20. The control unit 40 is detachably connected to the LED sheet 20 via a connector (not shown) provided on the LED sheet 20. That is, the control unit 40 is separate from the LED sheet 20 and is connected externally to the LED sheet 20. In other words, the control unit 40 is not integrated with the LED sheet 20. Thus, the control unit 40 can be separated from the LED sheet 20 and can be set at any location. Therefore, even in a limited space, the LED sheet 20 can be easily installed in the culture tube 10.

[0097] The control unit 40 also includes a power input unit 41, an AC / DC converter (driver) 42, and a PWM control unit 43. The power input unit 41 is supplied with an AC voltage having any voltage, for example, between 100 V and 240 V. The AC / DC converter 42 converts the 100 V to 240 V AC voltage into a constant DC voltage (for example, 44 V). The PWM control unit 43 dims the LED chips 21 of the LED sheet 20 by arbitrarily varying the pulse width of the constant voltage waveform from the AC / DC converter 42. In other words, the PWM control unit 43 also functions as a dimming control unit that controls the dimming of the LED sheet 20. The constant voltage output from the PWM control unit 43 is applied to the LED sheet 20.

[0098] In this embodiment, a constant DC voltage is applied to the LED chips 20 from the PWM control unit 43 of the control unit 40. This allows dimming of the LED chips 21, unlike when a rectified pulse voltage is directly applied to the LED chips 20. That is, the PWM control unit 43 can arbitrarily control the illumination of the LED chips 21 by appropriately changing the duty cycle of the DC voltage from the AC / DC converter 42. For example, Figure 6A As shown, the PWM control unit 43 can reduce the illuminance of the LED chip 21 by suppressing the duty ratio of the constant voltage from the AC / DC converter 42 from 100% (solid line) to 50% (dashed line).

[0099] While adjusting the illumination of the LED chip 21 in this manner, the illumination of the LED sheet 20 can also be adjusted according to, for example, the growth rate of the algae. This allows the algae's growth rate to be adjusted. For example, the illumination of the LED sheet 20 can be lowered in the early stages of growth when the algae are relatively small, and increased in the later stages of growth when the algae are larger and growing vigorously within the culture tube 10. Another example of adjusting the illumination of the LED sheet 20 is to increase the illumination for algae that require high illumination and to decrease the illumination for algae that can be cultivated even with low illumination. Furthermore, the illumination can be increased when the shipping date is desired to be advanced, and decreased when the shipping date is desired to be delayed.

[0100] In addition, by applying a DC constant voltage to the LED sheet 20 from the PWM control unit 43, the integrated light quantity per unit time of the light from the LED sheet 20 can be increased. That is, for example, the integrated light quantity ( Figure 6A The area of the shaded portion) is greater than the cumulative light intensity ( Figure 6A Thus, the luminous efficiency of the light from the LED sheet 20 can be improved, thereby improving the cultivation efficiency of algae.

[0101] Refer again Figure 3 , a regulator 45 is provided on the LED sheet 20. In this case, the regulator 45 is provided corresponding to each column of the LED chips 21. Specifically, ten regulators 45 are provided corresponding to ten columns of LED chips 21. The regulator 45 plays the role of keeping the current flowing through the multiple LED chips 21 in each column constant. Thus, even if one LED chip 21 is damaged, it is possible to suppress excessive current from flowing through the LED chips 21 in other columns, and the LED chips 21 in other columns will not be damaged. As a result, it is possible to prevent the overall illumination of the LED sheet 20 from being extremely reduced, and it is possible to suppress the deviation of the light irradiated into the space.

[0102] As described above, the LED chip 20 includes power receiving terminals 61 and power supply terminals 62. The power receiving terminals 61 and power supply terminals 62 are each located on the front surface 31a of the substrate 31 and are connected to the metal wiring portion 32, described later. The power receiving terminals 61 and power supply terminals 62 are used to connect the LED chip 20 to other LED chips 20. Specifically, the power receiving terminals 61 are used to receive power from the control unit 40 or other LED chips 20. The power supply terminals 62 are used to supply power to other LED chips 20. Details of the power receiving terminals 61 and power supply terminals 62 will be described later.

[0103] (Components of LED Sheet)

[0104] Next, each component constituting the LED sheet 20 will be described. Figure 7 As shown, the LED sheet 20 includes a flexible wiring substrate 30 and a plurality of LED chips 21 arranged on the flexible wiring substrate 30. The flexible wiring substrate 30 includes a substrate 31 and a metal wiring portion 32 on the substrate 31. The metal wiring portion 32 is laminated on the substrate 31 via an adhesive layer 33. The substrate 31 has a front surface (first surface) 31a, which is the surface facing the light-emitting surface 20a, and a back surface (second surface) 31b located opposite the front surface 31a.

[0105] Each LED chip 21 is mounted so as to be electrically connected to the metal wiring portion 32. In the LED sheet 20, by mounting the LED chips 21 on the flexible wiring substrate 30, a plurality of LED chips 21 can be arranged at a desired high density.

[0106] The metal wiring portion 32 is located on the front surface 31a of the substrate 31. A light-reflective insulating protective film 34 is formed on the metal wiring portion 32. This light-reflective insulating protective film 34 is not formed in the areas of the LED sheet 20 where the LED chips 21, the regulator 45, the power receiving terminals 61, or the power supply terminals 62 are located. Furthermore, this light-reflective insulating protective film 34 is not formed in the areas surrounding the areas where the LED chips 21, the regulator 45, the power receiving terminals 61, or the power supply terminals 62 are located. The light-reflective insulating protective film 34 is a layer that combines an insulating function, which helps improve the migration resistance of the LED sheet 20, with a light-reflecting function, which helps improve the light environment created by the LED sheet 20. This layer is formed from an insulating resin composition containing white pigment. If both migration resistance and light-reflecting function can be achieved by the aforementioned metal wiring portion 32 and the transparent protective film 35 described below, the light-reflective insulating protective film 34 need not be formed on the metal wiring portion 32.

[0107] A transparent protective film 35 is formed to cover the light-reflective insulating protective film 34 and the LED chip 21. The transparent protective film 35 is a resin film formed on the outermost surface (the surface closest to the light-emitting surface 20a) of the LED sheet 20 mainly to ensure waterproofness.

[0108] Furthermore, the metal wiring portion 32 is provided with a soldering portion 36 . Each LED chip 21 is electrically connected to the metal wiring portion 32 via the soldering portion 36 .

[0109] Refer again Figure 3 The LED sheet 20 further includes power supply wiring 63 that connects the metal wiring portion 32 to the power receiving terminals 61 and the power supply terminals 62. The power supply wiring 63 branches from the power receiving terminals 61. Furthermore, the power supply wiring 63 is arranged on the front surface 31a of the substrate 31, outside the LED chips 21, surrounding the rows R of ten LED chips. The power supply wiring 63 is electrically connected to the power supply wiring 63 of other LED sheets 20 having the same structure as the LED sheet 20. Specifically, the power supply wiring 63 is detachably connected to the power supply wiring 63 of the LED sheet 20 via the power supply terminals 62 and the other power receiving terminals 61 of the other LED sheet 20. Current from the power supply wiring 63 is supplied to the other LED sheet 20 via the power supply terminals 62 and the power receiving terminals 61 of the other LED sheet 20. This allows two LED sheets 20 to be connected and simultaneously controlled by a single control unit 40. Since a plurality of LED sheets 20 can be controlled simultaneously by one control unit 40, the number of control units 40 can be reduced, thereby suppressing an increase in the size of the culture system 1. Therefore, the culture system 1 can be easily installed even in a limited space.

[0110] (Substrate)

[0111] In this embodiment, substrate 31 is flexible. A flexible resin film can be used for substrate 31. It should be noted that, in this specification, "flexible" means "having a curvature radius of at least 1 meter when bent, preferably 50 cm, more preferably 30 cm, further preferably 10 cm, and particularly preferably 5 cm."

[0112] In this embodiment, the substrate 31 includes a protruding portion 31c protruding outward. The power supply terminal 62 is formed on the protruding portion 31c.

[0113] The planar shape of the substrate 31 may be substantially the same as the overall planar shape of the LED sheet 20, or may be a quadrilateral (rectangular) (see FIG. Figure 3 ). However, the planar shape of the substrate 31 is not particularly limited. The planar shape of the substrate 31 can be, for example, a k-gon (k is a natural number greater than or equal to 3). Furthermore, the upper limit of k is not particularly limited and can be, for example, less than or equal to 8 or less than or equal to 6. In this specification, the planar shape of the substrate 31 refers to the planar shape of the area of the substrate 31 excluding the protrusion 31c on which the power receiving terminal 61 or the power supply terminal 62 is formed.

[0114] As the material of the substrate 31, a thermoplastic resin with high heat resistance and insulation properties can also be used. As such resins, polyimide resin (PI) and polyethylene naphthalate (PEN) that are excellent in heat resistance, dimensional stability when heated, mechanical strength, and durability can be used. Among them, polyethylene naphthalate (PEN) that has been improved in heat resistance and dimensional stability by performing heat resistance-improving treatments such as annealing is preferably used. In addition, polyethylene terephthalate (PET) that has been improved in flame retardancy by adding flame retardant inorganic fillers can also be used.

[0115] The front surface 31a of the substrate 31 faces the culture tube 10. The front surface 31a is preferably colored white. This effectively reflects light leaking from the culture tube 10 to the outside, thereby further improving light utilization efficiency.

[0116] The thickness of substrate 31 is not particularly limited. To ensure that the substrate 31 serves as a heat dissipation path without becoming a bottleneck, to ensure a balance between heat resistance and insulation properties, and to maintain manufacturing costs, the thickness of substrate 31 is preferably approximately 10 μm or greater, and more preferably 50 μm or greater. Furthermore, the thickness of substrate 31 is preferably 500 μm or less, and more preferably 250 μm or less. Furthermore, to maintain good productivity during roll-to-roll manufacturing, the thickness of substrate 31 is preferably within the above-mentioned thickness range.

[0117] (Adhesive layer)

[0118] A known resin adhesive can be used as the adhesive forming the adhesive layer 33. Among these resin adhesives, urethane-based, polycarbonate-based, silicone-based, ester-based, or epoxy-based adhesives are particularly preferably used.

[0119] (Metal wiring part)

[0120] The metal wiring portion 32 is a wiring pattern formed by a conductive base material such as metal foil on the front surface 31a of the substrate 31 (the surface on the light-emitting surface 20a side). The metal wiring portion 32 is preferably formed on the front surface 31a of the substrate 31 by a dry lamination method via an adhesive layer 33. The metal wiring portion 32 includes the above-mentioned multiple metal wiring portions 22. The multiple metal wiring portions 22 include a first metal wiring portion 22A and a second metal wiring portion 22B arranged separately from the first metal wiring portion 22A. The LED chip 21 is mounted on the first metal wiring portion 22A and the second metal wiring portion 22B, and the LED chip 21 is electrically connected to the first metal wiring portion 22A and the second metal wiring portion 22B. The LED chip 21 is lit by the power supplied to the first metal wiring portion 22A and the second metal wiring portion 22B.

[0121] The metal wiring portion 32 preferably has both high heat dissipation and electrical conductivity. For example, copper foil can be used. In this case, heat dissipation from the LED chips 21 is stabilized, preventing an increase in resistance. Consequently, variations in light emission between the LED chips 21 are minimized, enabling stable light emission. This also extends the life of the LED chips 21. Furthermore, thermal degradation of peripheral components such as the substrate 31 can be prevented, thereby extending the product life of the LED sheet 20. Examples of metals that can form the metal wiring portion 32 include, in addition to the aforementioned copper, aluminum, gold, silver, and other metals.

[0122] The thickness of the metal wiring portion 32 can be appropriately set based on the current withstand capability required of the flexible wiring substrate 30. However, to prevent warping of the substrate 31 due to thermal contraction during soldering processes such as reflow, the thickness of the metal wiring portion 32 is preferably 10 μm or greater. On the other hand, the thickness of the metal wiring portion 32 is preferably 50 μm or less. This maintains sufficient flexibility of the flexible wiring substrate 30 and prevents degradation of operability due to increased weight.

[0123] (Welding Department)

[0124] The soldering portion 36 performs bonding between the metal wiring portion 32 and the LED chip 21. This bonding using solder can be performed using either a reflow method or a laser method.

[0125] (LED chip)

[0126] The LED chip 21 is a light-emitting element that utilizes the PN junction formed by the bonding of a P-type semiconductor and an N-type semiconductor. The LED chip 21 may have a structure in which a P-type electrode and an N-type electrode are provided on the upper and lower surfaces of the element, respectively, or a structure in which both a P-type electrode and an N-type electrode are provided on a single surface of the element.

[0127] Furthermore, it is preferred to select an LED chip 21 with high luminous efficiency. Specifically, it is preferred to use an LED chip 21 with a luminous efficiency of 150 lm / W or higher, and more preferably, a chip with a luminous efficiency of 180 lm / W or higher. By increasing the luminous efficiency of the LED chip 21 to 150 lm / W or higher, the number (density) of LED chips 21 installed can be reduced, reducing heat generation caused by Joule heat from the LED chip 21. This can prevent degradation of peripheral components such as the substrate 31 caused by heat from the LED chip 21.

[0128] As described above, the LED sheet 20 is constructed by directly mounting the LED chips 21 on the metal wiring portion 32, which exhibits high heat dissipation properties. This allows the excess heat generated when the LED chips 21 are lit to be rapidly dissipated through the metal wiring portion 32, even when the LED chips 21 are arranged at a high density. Consequently, heat can be sufficiently dissipated to the exterior of the LED sheet 20 via the substrate 31, preventing deterioration of the substrate 31 and other surrounding components caused by heat from the LED chips 21.

[0129] (Light-reflective insulating protective film)

[0130] like Figure 7 As shown, the light-reflective insulating protective film 34 is formed in areas other than the area where the LED chip 21 is located and its surrounding areas. This light-reflective insulating protective film 34 is a so-called resist layer that improves the migration resistance of the flexible wiring substrate 30 by providing sufficient insulation. Furthermore, the light-reflective insulating protective film 34 is a light-reflecting layer that has light reflectivity that contributes to increasing the luminance of light emitted in the light environment created by the LED sheet 20.

[0131] The light-reflective insulating protective film 34 can be formed from various resin compositions having a carbamate resin as a base resin and further containing a white pigment composed of an inorganic filler such as titanium oxide. As the base resin of the resin composition for forming the light-reflective insulating protective film 34, in addition to the carbamate resin, an acrylic polyurethane resin, a polyester resin, a phenolic resin, etc. can also be used as appropriate. As the base resin of the resin composition forming the light-reflective insulating protective film 34, it is more preferable to use a resin that is the same as or of the same series as the resin composition forming the transparent protective film 35 as the base resin. As described later, for the transparent protective film 35, it is preferable to use an acrylic polyurethane resin as the main material resin. Therefore, in the case where the base resin of the resin composition forming the transparent protective film 35 is an acrylic polyurethane resin, the base resin of the resin composition for forming the light-reflective insulating protective film 34 is more preferably a carbamate resin or an acrylic polyurethane resin.

[0132] As an inorganic filler contained as a white pigment in the resin composition forming the light-reflective insulating protective film 34, in addition to titanium oxide, at least one selected from aluminum oxide, barium sulfate, magnesium oxide, aluminum nitride, boron nitride, barium titanate, kaolin, talc, calcium carbonate, zinc oxide, silica, mica powder, glass powder, nickel powder and aluminum powder can be used.

[0133] The thickness of the light-reflective insulating protective film 34 is 5 μm or greater, more preferably 7 μm or greater. Furthermore, the thickness of the light-reflective insulating protective film 34 is 50 μm or less, more preferably 20 μm or less. By setting the thickness of the light-reflective insulating protective film 34 to 5 μm or greater, it is possible to prevent the light-reflective insulating protective film 34 from becoming thinner, particularly at the edges of the metal wiring portion 32. This prevents the metal wiring portion 32 from being exposed. Furthermore, by setting the thickness of the light-reflective insulating protective film 34 to 50 μm or less, it is possible to prevent the light-reflective insulating protective film 34 from peeling off from the metal wiring portion 32, even if the flexible wiring substrate 30 is bent during transportation, for example.

[0134] Furthermore, the light reflectivity of the light-reflective insulating protective film 34 at wavelengths between 400 nm and 780 nm is preferably 65% or higher, more preferably 70% or higher, and even more preferably 80% or higher. In this case, the LED sheet 20 may contain, for example, 20 parts by mass or higher of titanium oxide per 100 parts by mass of a urethane or acrylic polyurethane base resin. This allows the light reflectivity of the light-reflective insulating protective film 34 to be 75% or higher in the same layer when the thickness is 8 μm.

[0135] (Transparent protective film)

[0136] A transparent protective film 35 is formed on the outermost surface of the LED sheet 20, covering the LED chips 21. The transparent protective film 35 is both waterproof and transparent. The waterproof nature of the transparent protective film 35 prevents water from entering the interior of the LED sheet 20. For example, if a high-efficiency LED chip, such as one with a luminous efficiency of 150 lm / W or greater, is selected as the LED chip 21, the impact of damage to a specific LED chip 21 in the LED sheet 20 becomes significant. Therefore, from a risk management perspective, it is important to make the LED chip 21 as difficult to damage as possible.

[0137] The transparent protective film 35 can be formed from various resin compositions based on an acrylic polyurethane resin or the like. In addition to acrylic polyurethane resins, urethane resins, polyester resins, phenolic resins, and the like can also be used as the base resin for the resin composition forming the transparent protective film 35. The base resin for the resin composition forming the transparent protective film 35 is preferably the same as or a similar resin to that used to form the light-reflective insulating protective film 34. A preferred specific combination includes a urethane resin as the base resin for the resin composition forming the light-reflective insulating protective film 34 and an acrylic polyurethane resin as the base resin for the transparent protective film 35.

[0138] The thickness of the transparent protective film 35 is 10 μm or greater, preferably 15 μm or greater, and more preferably 20 μm or greater. Alternatively, the thickness of the transparent protective film 35 is 40 μm or less, preferably 30 μm or less, and more preferably 25 μm or less. By setting the thickness of the transparent protective film 35 within the above range, the LED sheet 20 can maintain its excellent flexibility, thinness, and lightness, as well as the excellent optical properties required in emergency situations. Furthermore, the LED sheet 20 can be provided with sufficient waterproofing required in emergency situations.

[0139] The water resistance of the LED sheet 20 achieved by the transparent protective film 35 is not particularly limited as long as it is a degree that can suppress the degradation of the LED chip 21 when water is spread on the LED sheet 20. As such water resistance, it is preferred to show IPX4 or above in the waterproof / dustproof protection standard specified by IEC (International Electrotechnical Commission). Waterproofness above IPX4 is a degree that does not cause harmful effects on the LED chip 21 due to water droplets from all directions. Specifically, it is to such an extent that when water is sprayed from a sprinkler nozzle at a rate of 10 L / min for 5 minutes within the entire range of ±180° relative to the normal direction of the LED sheet 20, no harmful effects are caused to the LED chip 21.

[0140] (Power supply wiring)

[0141] like Figure 8 As shown, the power supply wiring 63 is formed on the front surface 31a of the substrate 31 (the surface facing the light-emitting surface 20a). The power supply wiring 63 is a wiring pattern formed on the front surface 31a of the substrate 31 using a conductive base material such as metal foil. The power supply wiring 63 can also be formed using the same materials and methods as the metal wiring portion 32. For example, the power supply wiring 63 can also be formed from copper foil.

[0142] The thickness of the power supply wiring 63 may be appropriately set according to the current withstand capability required of the flexible wiring substrate 30. The thickness T1 of the power supply wiring 63 (see Figure 8 ) can be 18 μm or more, preferably 35 μm or more. In addition, the thickness T1 of the power supply wiring 63 can be 100 μm or less, preferably 75 μm or less. In addition, the line width W1 of the power supply wiring 63 (see Figure 8 ) can be 5 mm or more, preferably 10 mm or more. Furthermore, the line width W1 of the power supply wiring 63 can also be 30 mm or less, preferably 20 mm or less. By making the thickness T1 of the power supply wiring 63 more than 18 μm and the line width W1 of the power supply wiring 63 more than 5 mm, the cross-sectional area of the power supply wiring 63 can be increased in the cross section perpendicular to the longitudinal direction of the power supply wiring 63. Thus, the voltage drop can be reduced. In addition, by making the thickness T1 of the power supply wiring 63 less than 100 μm and the line width W1 of the power supply wiring 63 less than 30 mm, the sufficient flexibility of the LED sheet 20 can be maintained, and the reduction in operability caused by the increase in weight can also be suppressed.

[0143] However, as described above, the LED sheet 20 includes a power receiving terminal 61 and a power supply terminal 62. The power receiving terminal 61 and the power supply terminal 62 are respectively connected to the metal wiring portion 32. The power receiving terminal 61 and the power supply terminal 62 are conductors. That is, the power receiving terminal 61 and the power supply terminal 62 are terminals formed of a conductive base material such as metal foil. The power receiving terminal 61 and the power supply terminal 62 can also be formed of the same material and method as the metal wiring portion 32. For example, the power receiving terminal 61 and the power supply terminal 62 can also be made of copper foil. In this embodiment, the power receiving terminal 61 and the power supply terminal 62 are formed integrally with the metal wiring portion 32. In addition, the power receiving terminal 61 and the power supply terminal 62 can also be formed separately from the metal wiring portion 32.

[0144] The thickness T2 of the power receiving terminal 61 (see Figure 10 ) and the thickness T3 of the power supply terminal 62 (refer to Figure 10) can be 18 μm or more, preferably 35 μm or more. In addition, the thickness T2 of the power receiving terminal 61 and the thickness T3 of the power supply terminal 62 can be 100 μm or less, preferably 75 μm or less. By making the thickness T2 of the power receiving terminal 61 and the thickness T3 of the power supply terminal 62 less than 100 μm, respectively, it is possible to suppress the formation of large bumps on the light-emitting surface 20a. In addition, by making the thickness T2 of the power receiving terminal 61 and the thickness T3 of the power supply terminal 62 less than 75 μm, respectively, it is possible to more effectively suppress the formation of large bumps on the light-emitting surface 20a. Therefore, the LED sheet assembly 20A can be easily wound on the culture tube 10. In addition, as Figure 9 As shown, in this embodiment, the power supply terminal 62 is formed on the protruding portion 31c.

[0145] Here, as described above, the LED chip assembly 20A includes the first LED chip 201, the second LED chip 202, and the third LED chip 203. The power receiving terminal 61 of the first LED chip 201 is connected to the control unit 40 (see Figure 3 ). In addition, Figure 9 As shown, the power supply terminals 62 of the first LED chip 201 are connected to the power receiving terminals 61 of the second LED chip 202. Furthermore, the power supply terminals 62 of the second LED chip 202 are connected to the power receiving terminals 61 of the third LED chip 203. In this case, the power supply terminals 62 of the first LED chip 201 and the power receiving terminals 61 of the second LED chip 202 are connected in parallel. Furthermore, the power supply terminals 62 of the second LED chip 202 and the power receiving terminals 61 of the third LED chip 203 are connected in parallel.

[0146] At least a portion of the power receiving terminal 61 and at least a portion of the power supply terminal 62 are exposed. In other words, the power receiving terminal 61 and the power supply terminal 62 each have an area not covered by the insulator. Furthermore, the power receiving terminal 61 and the power supply terminal 62 may be connected to each other by bringing the exposed portion of the power receiving terminal 61 into contact with the exposed portion of the power supply terminal 62. As an example, the power supply terminal 62 of the first LED sheet 201 may be connected to the power receiving terminal 61 of the second LED sheet 202 as follows. For example, first, as Figure 10As shown, in the first LED sheet 201, a part of the protrusion 31c of the substrate 31 and a part of the adhesive layer 33 are removed, thereby exposing the power supply terminal 62. In the example shown in the figure, the surface of the power supply terminal 62 on the side opposite to the light-emitting surface 20a is exposed. In addition, in the second LED sheet 202, a part of the transparent protective film 35 and a part of the light-reflective insulating protective film 34 are removed, thereby exposing the power receiving terminal 61. In the example shown in the figure, the surface of the power receiving terminal 61 on the side of the light-emitting surface 20a is exposed. Moreover, the power supply terminal 62 of the first LED sheet 201 and the power receiving terminal 61 of the second LED sheet 202 may be connected to each other by bringing them into contact. In addition, the LED sheet 20 may be manufactured in advance in such a manner that the power receiving terminal 61 and the power supply terminal 62 are exposed. In addition, the power supply terminal 62 may be capable of being folded back toward the back surface 31b side of the substrate 31. In this case, for example, first, as Figure 11 As shown, in the first LED chip 201, the power supply terminal 62 may be exposed from a portion of the transparent protective film 35 and a portion of the light-reflective insulating protective film 34. In the illustrated example, the surface of the power supply terminal 62 on the light-emitting surface 20a side is exposed. Furthermore, the power supply terminal 62 of the first LED chip 201 may be brought into contact with the power receiving terminal 61 of the second LED chip 202 by bending the protruding portion 31c of the first LED chip 201. In these cases, the power receiving terminal 61 and the power supply terminal 62 may be joined to each other using, for example, solder, conductive paste, or crimping. Furthermore, although not illustrated, the surface of the power receiving terminal 61 on the side opposite to the light-emitting surface 20a may be exposed.

[0147] In the LED chip assembly 20A, the power receiving terminal 61 and the power supply terminal 62 may be covered by an insulator (eg, substrate 31, light reflective insulating protective film 34 or transparent protective film 35). Figure 10 and Figure 11 As shown, the power receiving terminal 61 and the power supply terminal 62 may be brought into contact with each other and then covered with an insulator. Although not shown, after the power receiving terminal 61 and the power supply terminal 62 are connected to each other, the power receiving terminal 61 and the power supply terminal 62 may be covered with an insulator such as an insulating adhesive tape.

[0148] In addition, if Figure 1 and Figure 2As shown, in the present embodiment, the LED sheet 20 is bonded to the culture tube 10 by means of an adhesive component 50. Thus, the presence of an air layer between the LED sheet 20 and the culture tube 10 can be suppressed. Here, if an air layer is present between the LED sheet 20 and the culture tube 10, the light from the LED chip 21 will be reflected on the outer surface of the culture tube 10 due to the difference between the refractive index of the air and the refractive index of the culture tube 10. Moreover, since the reflectivity of the light increases, the efficiency of light utilization in the culture system 1 may decrease. In contrast, in the present embodiment, the presence of an air layer between the LED sheet 20 and the culture tube 10 can be suppressed. Therefore, the reflection of the light from the LED chip 21 on the outer surface of the culture tube 10 can be suppressed. As a result, the efficiency of light utilization can be further improved. In the present embodiment, the adhesive component 50 is provided so as to cover the entire light-emitting surface 20a of the LED sheet 20.

[0149] The adhesive component 50 preferably comprises ethylene vinyl acetate or polyvinyl butyral. Alternatively, the adhesive component 50 may comprise an adhesive. The adhesive is not particularly limited. Examples of adhesives include natural rubber, butyl rubber, polyisoprene, polyisobutylene, polychloroprene, styrene polymers, silicone resins, acrylic resins, polyvinyl acetate, ethylene-vinyl acetate copolymers, and other vinyl acetate resins; urethane resins; acrylonitrile; hydrocarbon resins; alkylphenol resins; rosin; rosin triglyceride; and hydrogenated rosin. Alternatively, the adhesive component 50 may be a commercially available double-sided adhesive film.

[0150] The refractive index of the adhesive member 50 can be greater than 1.48, greater than 1.50, or greater than 1.51. In addition, the refractive index of the adhesive member 50 can be less than 1.60, less than 1.58, or less than 1.56. Here, as described above, for the culture tube 10, for example, glass (refractive index: about 1.55) or polycarbonate (refractive index: about 1.58) is used. Therefore, by making the refractive index of the adhesive member 50 greater than 1.48 and less than 1.60, the difference between the refractive index of the adhesive member 50 and the refractive index of the culture tube 10 can be reduced. Thereby, it is possible to suppress the reflection of light from the LED chip 21 on the outer surface of the culture tube 10. Therefore, the utilization efficiency of light can be further improved. It should be noted that the refractive index of the adhesive member 50 and the culture tube 10 can be measured, for example, using a refractometer (manufactured by ATAGO Co., Ltd., Abbe refractometer, DR-A1 (product name)).

[0151] like Figure 2 As shown, the surface 51 of the adhesive member 50 faces the culture tube 10. Figure 12As shown, a mesh-shaped recess 52 is formed on the surface 51. The recess 52 functions as an exhaust mechanism for exhausting the air between the adhesive member 50 and the culture tube 10.

[0152] In this embodiment, the recess 52 includes a plurality of first portions 52a and a plurality of second portions 52b. Each first portion 52a extends along the first arrangement direction (X direction) of the LED chips 21. In the illustrated example, the first portions 52a are spaced evenly apart. Alternatively, the first portions 52a may extend in a direction oblique to the X direction. Furthermore, the spacing between the first portions 52a may vary.

[0153] Each second portion 52b extends along the second arrangement direction (Y direction) of the LED chips 21. In the illustrated example, the second portions 52b are spaced equally apart. Alternatively, the second portions 52b may extend in a direction oblique to the Y direction. Furthermore, the spacing between the second portions 52b may vary.

[0154] The peel strength between the LED sheet 20 and the culture tube 10 is preferably 3N / 15mm or more, more preferably 4N / 15mm or more, and even more preferably 5N / 15mm or more. In addition, the peel strength between the LED sheet 20 and the culture tube 10 is preferably 30N / 15mm or less, more preferably 20N / 15mm or less, and even more preferably 15N / 15mm or less. By setting the peel strength between the LED sheet 20 and the culture tube 10 to 3N / 15mm or more, it is possible to prevent the LED sheet 20 from peeling off from the culture tube 10 during use. In addition, by setting the peel strength between the LED sheet 20 and the culture tube 10 to 30N / 15mm or less, it is possible to prevent, for example, a portion of the adhesive component 50 from adhering to the culture tube 10 when the LED sheet 20 is peeled off from the culture tube 10. In addition, by setting the peel strength between the LED sheet 20 and the culture tube 10 to 30N / 15mm or less, it is possible to easily peel the LED sheet 20 from the culture tube 10 when replacing the LED sheet 20, etc. The peel strength between the LED sheet 20 and the culture tube 10 can be measured using, for example, a material testing machine (Tensilon Universal Material Testing Machine RTF-2325 (product name), manufactured by A&D Corporation).

[0155] In addition, the photosynthetic photon flux density (PPFD (photosynthetic photon flux density)) I0 of the LED sheet 20 is preferably 250 μmol / m -2 ·s -1By setting the photosynthetic photon flux density I0 of the LED sheet 20 to 250 μmol / m -2 ·s -1 The above can improve the algae cultivation efficiency. It should be noted that PPFD can be measured by a measuring device such as a photon meter (for example, the photon sensor LI-190R and the photometer LI-250A manufactured by LI-COR Corporation of the United States).

[0156] Here, the molar absorption coefficient of the culture solution CS in the culture tube 10 is ε (L·cm -1 ·g -1 ), the molar concentration of the culture solution CS is set to C (g·L -1 ), the inner diameter d1 of the culture tube 10 (refer to Figure 1 ) is set to D (cm),

[0157] The photosynthetic photon flux density I0 of the LED sheet 20 preferably satisfies the following relationship:

[0158] 250 / 10 (-εCD / 2) ≤I0≤250 / 10 (-εCD)

[0159] This can improve the efficiency of algae cultivation and reduce power consumption.

[0160] In addition, when the absorbance is represented by A and the transmittance is represented by T, the following equation (1) holds true according to the Lambert-Beer law.

[0161] A=-log 10 T=εCD……Formula (1)

[0162] In addition, when the photosynthetic photon flux density transmitted through the culture solution CS is defined as I, the transmittance T can be expressed by the following formula (2).

[0163] T=I / I0……Formula (2)

[0164] Therefore, based on equations (1) and (2), the photosynthetic photon flux density I0 can be expressed by the following equation (3).

[0165] I0=I / 10 -εCD ...Formula (3)

[0166] As described above, the photosynthetic photon flux density I0 of the LED sheet 20 is preferably 250 μmol / m -2 ·s -1In addition, in the culture tube 10, the position where the photosynthetic photon flux density I0 of the LED sheet 20 is the lowest is considered to be the radial center of the culture tube 10. Therefore, in the radial center of the culture tube 10, the photosynthetic photon flux density I0 of the LED sheet 20 is preferably 250 μmol / m -2 ·s -1 In this case, by satisfying

[0167] 250 / 10 (-εCD / 2) ≤I0

[0168] This relationship enables the photosynthetic photon flux density I0 of the LED sheet 20 to be 250 μmol / m -2 ·s -1 Therefore, by meeting 250 / 10 (-εCD / 2) ≤I0, the cultivation efficiency of algae can be improved. In addition, by satisfying I0≤250 / 10 (-εCD) This relationship can reduce power consumption.

[0169] (Method for Manufacturing LED Sheet)

[0170] Next, refer to 13A to 13H A method for manufacturing the LED sheet 20 of this embodiment will be described.

[0171] First, prepare the substrate 31 ( Figure 13A Next, on the front surface 31a of the substrate 31 (see Figure 7 ) is laminated to form a metal foil 32A such as copper foil, which is a material of the metal wiring portion 32, the power receiving terminal 61, the power supply terminal 62, and the power supply wiring 63 (hereinafter also referred to as the metal wiring portion 32, etc.). Figure 13B The metal foil 32A is bonded to the front surface 31a of the substrate 31 via an adhesive layer 33 such as a urethane adhesive. Alternatively, the metal foil 32A may be formed directly on the front surface 31a of the substrate 31 by electroplating or vapor deposition (sputtering, ion plating, electron beam evaporation, vacuum evaporation, chemical evaporation, etc.). Alternatively, the metal foil 32A may be formed by directly welding the substrate 31 onto the metal foil 32A.

[0172] Next, an etching mask 37 ( ) patterned into a desired shape such as the metal wiring portion 32 is formed on the surface of the metal foil 32A. Figure 13CThe etching mask 37 is provided so that the portion corresponding to the wiring pattern of the metal foil 32A, which will become the metal wiring portion 32, is not corroded by the etching solution. The method for forming the etching mask 37 is not particularly limited. For example, the etching mask 37 can be formed by exposing a photoresist or dry film to light through a photomask and then developing the film. Alternatively, the etching mask 37 can be formed on the surface of the metal foil 32A using a printing technique such as an inkjet printer.

[0173] Next, the metal foil 32A located in the portion not covered by the etching mask 37 is removed using the immersion liquid ( Figure 13D ) As a result, portions of the metal foil 32A other than the portions to be used as the metal wiring portion 32 and the like are removed.

[0174] Thereafter, the etching mask 37 is removed using an alkaline stripping solution. Thus, the etching mask 37 is removed from the surface of the metal wiring portion 32 and the like ( Figure 13E ).

[0175] Next, a light-reflective insulating protective film 34 ( Figure 13F The formation of the light-reflective insulating protective film 34 is not particularly limited as long as the coating method can evenly apply the resin composition constituting the light-reflective insulating protective film 34. For example, methods such as screen printing, offset printing, dip coating, and brush coating can be used. Alternatively, the entire surface may be coated with a photosensitive insulating protective film material, and only the necessary areas may be exposed to light through a photomask, and then developed to form the light-reflective insulating protective film 34. In addition, the light-reflective insulating protective film 34 does not need to be formed on the power supply terminals 62 and the power supply wiring 63.

[0176] Next, the LED chip 21 is mounted on the metal wiring portion 32 ( Figure 13G ). In addition, Figure 13G and the following Figure 13H In order to make the drawing clear, the adjuster 45 and the like are omitted. In this case, the LED chip 21 is bonded to the metal wiring portion 32 by soldering via the soldering portion 36. The soldering process can be performed by a reflow method or a laser method, or can be performed by a conductive resin.

[0177] Next, a transparent protective film 35 ( Figure 13H). The transparent protective film 35 is preferably formed by the following methods: a method of forming by spraying a transparent resin composition using a spray coating process (hereinafter referred to as the "spray coating method"); or a method of forming by a curtain coating method. Regarding the formation of the transparent protective film 35 based on the spray coating method, it can be carried out, for example, in the following manner: using a spray coater, a coating liquid for spray coating containing an acrylic polyurethane resin is sprayed onto a desired area on the flexible wiring substrate 30 to form a coating film. Regarding the formation of the transparent protective film 35 based on the curtain coating method, it can be carried out, for example, in the following manner: using a curtain coater, a coating liquid for curtain coating containing an acrylic polyurethane resin is dropped onto a desired area on the flexible wiring substrate 30 to form a coating film.

[0178] The LED sheet 20 of this embodiment is not limited to the above-described method, and can be manufactured by a conventionally known method for manufacturing various LED sheets including flexible wiring boards for LED chips or LED chips mounted thereon.

[0179] (Cultivation Factory)

[0180] Figure 14 1 is a diagram schematically showing the structure of a culture factory 90 using the culture system 1 of this embodiment. The culture factory 90 includes a building 91 and a plurality of culture racks 80 arranged inside the building 91.

[0181] like Figure 15 As shown, the culture rack 80 includes a plurality of (four) pillars 82 and a pair of rack base plates 81 arranged at intervals in the vertical direction along the pillars 82. Furthermore, a plurality of culture systems 1 are arranged between the pair of rack base plates 81. In the example shown, the culture systems 1 are arranged so that the longitudinal direction of the culture tubes 10 is parallel to the vertical direction (vertical direction). Although not shown, the culture systems 1 may also be arranged so that the longitudinal direction of the culture tubes 10 is parallel to the horizontal direction.

[0182] Here, the control unit 40 is disposed sufficiently away from the culture tube 10. Therefore, there is less concern that the algae cultivation may vary due to heat from the control unit 40 between the culture tube 10 located near the control unit 40 and the culture tube 10 located far from the control unit 40.

[0183] The LED sheet 20 of this embodiment is thinner than conventional straight-tube lighting devices. This allows for narrower spacing between cultivation systems 1, increasing the number of cultivation systems 1 that can be placed between a pair of rack substrates 81. Consequently, the amount of algae cultivated per unit area can be increased.

[0184] Thus, according to this embodiment, the LED sheet 20 includes: a substrate 31; a metal wiring portion 32; a plurality of LED chips 21 mounted on the metal wiring portion 32; a power receiving terminal 61 connected to the metal wiring portion 32 for receiving power when connected to another LED sheet 20; and a power supply terminal 62 connected to the metal wiring portion 32 for supplying power when connected to another LED sheet 20. This makes it easy to connect LED sheets 20 to each other.

[0185] Here, the LED sheet 20 has a size of approximately 600 mm x 500 mm, for example. Therefore, assembling multiple LED sheets 20 in the cultivation factory 90 may be difficult. In contrast, in this embodiment, the LED sheets 20 can be easily connected. Therefore, multiple LED sheets 20 can be easily assembled in the cultivation factory 90. Furthermore, the LED sheet assembly 20A, formed by connecting the LED sheets 20, can be easily delivered to the cultivation factory 90.

[0186] Furthermore, since the LED sheets 20 can be easily connected to each other, it is easy to replace the LED sheets 20. In this case, if the LED chip 21 in a specific LED sheet 20 is damaged, only the LED sheet 20 can be easily replaced, so the LED sheet assembly 20A can be easily repaired.

[0187] According to this embodiment, the substrate 31 includes the protruding portion 31 c protruding outward. Furthermore, the power supply terminals 62 are formed on the protruding portion 31 c. This allows the power supply terminals 62 to be easily connected to the power receiving terminals 61 of other LED sheets 20.

[0188] Furthermore, according to this embodiment, the LED sheet 20 is provided with a display unit 25 that displays the ON state and the OFF state of the LED chip 21. Thus, even when the LED sheet 20 is wound around the culture tube 10, the ON state and the OFF state of the LED chip 21 can be easily confirmed.

[0189] In addition, according to this embodiment, the substrate 31 is flexible. Thus, the LED sheet 20 is a sheet-shaped LED lighting device having a flexible substrate 31, thereby enabling lightweighting of the LED sheet assembly 20A and the culture system 1. In addition, regarding the LED sheet 20 of the culture system 1 of this embodiment, the overall thickness can be made thinner compared to a straight-tube LED strip light in which a plurality of LEDs are arranged. Therefore, when the LED sheet 20 is wound around the culture tube 10, the increase in the volume of the culture system 1 can be suppressed. Thus, the installation space of the culture system 1 can be reduced. Furthermore, since the LED sheet 20 is a sheet-shaped LED lighting device having a flexible substrate 31, the LED sheet 20 can be easily installed on culture tubes 10 of various shapes.

[0190] Furthermore, according to this embodiment, in the LED chip assembly 20A, the power supply terminals 62 of the first LED chip 201 are connected in parallel with the power receiving terminals 61 of the second LED chip 202. Even if one LED chip 20 is damaged, damage to the other LED chips 20 is prevented. This prevents an extreme decrease in the overall illumination of the LED chip assembly 20A.

[0191] Furthermore, according to this embodiment, the LED chip assembly 20A further includes a connecting member 26 attached to the first LED chip 201 and the second LED chip 202. Furthermore, the second LED chip 202 is connected to the first LED chip 201 via the connecting member 26. This makes it easier to connect the LED chips 20 and prevents the second LED chip 202 from being accidentally removed from the first LED chip 201.

[0192] Furthermore, according to this embodiment, the cultivation system 1 includes a culture tube 10 for cultivating algae and an LED sheet assembly 20A covering the outer surface of the culture tube 10. This prevents light irradiated from the LED sheet 20 into the culture tube 10 from leaking outside the culture tube 10, thereby improving light utilization efficiency. Furthermore, since the LED sheet 20 covers the outer surface of the culture tube 10, light can be irradiated into the culture tube 10 from the entire circumference of the main body 11. Consequently, algae cultivation efficiency can be improved.

[0193] [Modification]

[0194] Then, according to Figures 16 to 24 , a modification of the LED sheet assembly 20A and the culture system 1 of this embodiment will be described. Figures 16 to 24 In, with Figures 1 to 15 The same parts are denoted by the same reference numerals and detailed descriptions are omitted.

[0195] (First Modification)

[0196] exist Figure 16 In the embodiment shown, the power receiving terminals 61 of the second LED chip 202 are formed on the protrusion 31c of the second LED chip 202. Furthermore, in the illustrated example, the protrusion 31c is not formed on the first LED chip 201, and the power supply terminals 62 of the first LED chip 201 are not formed on the protrusion 31c. However, this is not limiting; the protrusion 31c may be formed on the first LED chip 201, or the power supply terminals 62 of the first LED chip 201 may be formed on the protrusion 31c of the first LED chip 201. In this variation, since the power receiving terminals 61 are also formed on the protrusion 31c, the power receiving terminals 61 can be easily connected to the power supply terminals 62 of other LED chips 20.

[0197] (Second Modification)

[0198] exist Figure 17 In the example shown, the LED chip assembly 20A further includes a connecting member 27. In the illustrated example, the connecting member 27 is detachably attached to the first LED chip 201 and the second LED chip 202. Furthermore, the power supply terminals 62 of the first LED chip 201 and the power receiving terminals 61 of the second LED chip 202 are connected to each other via the connecting member 27. Although not illustrated, the LED chip assembly 20A may include multiple connecting members 27, and the connecting members 27 may be detachably attached to the second LED chip 202 and the third LED chip 203. Furthermore, the power supply terminals 62 of the second LED chip 202 and the power receiving terminals 61 of the third LED chip 203 may be connected to each other via the connecting member 27. Alternatively, the connecting member 27 may be non-detachably attached to the first LED chip 201, etc. In this case, the connecting member 27 may be attached to the first LED chip 201, etc., using solder, adhesive, or the like.

[0199] like Figure 18 As shown, the connecting component 27 has an insulating layer 27a and a metal layer 27b. The insulating layer 27a can also be formed by the same material and method as the light-reflective insulating protective film 34. The metal layer 27b can also be formed by the same material and method as the metal wiring portion 32. For example, the metal layer 27b can also be composed of copper foil. The thickness T4 of the metal layer 27b can be greater than 18μm, preferably greater than 35μm. In addition, the thickness T4 of the metal layer 27b can be less than 100μm, preferably less than 75μm. In addition, the width W2 of the metal layer 27b (the length in the Y direction, refer to Figure 17) can be 5 mm or more, preferably 10 mm or more. Furthermore, the width W2 of the metal layer 27b can be 30 mm or less, preferably 20 mm or less. By making the thickness T4 of the metal layer 27b 18 μm or more and the width W2 of the metal layer 27b 5 mm or more, the cross-sectional area of the metal layer 27b can be increased in the cross section perpendicular to the longitudinal direction (X direction) of the metal layer 27b. As a result, the voltage drop can be reduced. In addition, by making the thickness T4 of the metal layer 27b 100 μm or less and the width W2 of the metal layer 27b 30 mm or less, the sufficient flexibility of the LED sheet assembly 20A can be maintained, and the reduction in operability caused by the increase in weight can be suppressed.

[0200] In the illustrated example, the connecting member 27 connects the power receiving terminals 61 and the power supply terminals 62 from the light emitting surface 20a side of the LED chip 20, but the present invention is not limited thereto. The connecting member 27 may also connect the power receiving terminals 61 and the power supply terminals 62 from the side of the LED chip 20 opposite to the light emitting surface 20a.

[0201] According to this variation, the LED chip assembly 20A further includes a connecting member 27 that is detachably attached to the first LED chip 201 and the second LED chip 202. Furthermore, the power supply terminals 62 of the first LED chip 201 and the power receiving terminals 61 of the second LED chip 202 are connected to each other via the connecting member 27. In this case, the power supply terminals 62 can also be easily connected to the power receiving terminals 61 of other LED chips 20. Therefore, the LED chips 20 can be easily connected to each other.

[0202] (Third Modification)

[0203] exist Figure 19 In the embodiment, the plurality of LED sheets 20 are arranged along the first arrangement direction (X direction) and the second arrangement direction (Y direction) of the LED chips 21. Specifically, the LED sheets 20 are arranged in multiple stages and multiple columns in a plan view.

[0204] For example, Figure 19 In the embodiment, four LED sheets 20 are arranged along the first arrangement direction (X direction) of the LED chips 21. Furthermore, five rows of these four LED sheets are arranged along the second arrangement direction (Y direction) of the LED chips 21. The number of LED sheets 20 arranged is not limited to this.

[0205] Here, when multiple LED chips 20 are arranged along the first arrangement direction (X direction) and the second arrangement direction (Y direction) of the LED chips 21, one LED chip 20 may also include multiple power supply terminals 62. In other words, one LED chip 20 can supply power to other LED chips 20 adjacent to it in the X direction, and also supply power to other LED chips 20 adjacent to it in the Y direction.

[0206] In this case, when the planar shape of the substrate 31 is a k-gon (k is a natural number greater than or equal to 3), a plurality of power supply terminals 62 may be provided in the predetermined LED sheet 20. Furthermore, in the predetermined LED sheet 20, power supply terminals 62 may be provided at positions corresponding to at least two of the k sides of the k-gon. For example, Figure 19 In the example shown, in the LED sheet 204, power supply terminals 62 are provided at positions corresponding to two of the four sides of the quadrilateral. That is, in the LED sheet 204, power supply terminals 62 are provided at positions corresponding to side s1 and side s2 of the four sides. In addition, in the LED sheet 205, power supply terminals 62 are provided at positions corresponding to three of the four sides of the quadrilateral. That is, in the LED sheet 205, power supply terminals 62 are provided at positions corresponding to side s3, side s4, and side s5 of the four sides. In addition, for example, Figure 19 In the embodiment, when the LED chip 204 supplies power to the LED chip 205 adjacent in the Y direction, the terminal Te of the LED chip 204, which is located near the LED chip 205, can be set as the power supply terminal 62. On the other hand, when the LED chip 204 supplies power to the LED chip 205 adjacent in the Y direction, the terminal Te of the LED chip 204 can be set as the power supply terminal 62.

[0207] In addition, for example, in a given LED sheet 20, the number of power supply terminals 62 may be k-1 or less. Furthermore, each power supply terminal 62 may be provided at a position corresponding to a different side among the k sides of the k-gon. Figure 19 In the example shown, two power supply terminals 62 are provided on the LED sheet 204. Furthermore, each power supply terminal 62 is located at a position corresponding to a different side s1 or s2 of the four sides of the quadrilateral. Furthermore, three power supply terminals 62 are provided on the LED sheet 205. Furthermore, each power supply terminal 62 is located at a position corresponding to a different side s3, s4, and s5 of the four sides of the quadrilateral. Although not shown, multiple power supply terminals 62 may be provided at positions corresponding to a single side.

[0208] According to this modification, power supply terminals 62 are provided at positions corresponding to at least two of the k sides of the k-gon. This makes it possible to easily connect a plurality of LED sheets 20 and increase the size of the LED sheet assembly 20A.

[0209] Furthermore, according to this modified example, the number of power supply terminals 62 provided is k-1 or less, and each power supply terminal 62 is provided at a position corresponding to a different one of the k sides of the k-gon. In this case, multiple LED sheets 20 can be easily connected, enabling a larger LED sheet assembly 20A.

[0210] Furthermore, as described above, when the planar shape of the substrate 31 is a k-gon, the number of power supply terminals 62 may be k-1 or less in each LED sheet 20. For example, in this case, Figure 20A As shown, when the planar shape of the substrate 31 is a quadrilateral, two power supply terminals 62 may be provided in a given LED chip 20. In this case, a plurality of LED chips 20 may be connected to each other so that the LED chip assembly 20A has a cylindrical shape as a whole.

[0211] In addition, if Figure 20B As shown, when the planar shape of the substrate 31 is triangular, two power supply terminals 62 may be provided in a given LED chip 20. In this case, a plurality of LED chips 20 may be connected to form the LED chip assembly 20A as a whole into an octahedron.

[0212] In addition, if Figure 20C As shown, when the planar shape of the substrate 31 is a quadrilateral, three power supply terminals 62 may be provided in a given LED chip 20. In this case, a plurality of LED chips 20 may be connected to each other so that the LED chip assembly 20A is configured as a hexahedron as a whole.

[0213] In addition, if Figure 20D As shown, when the planar shape of the substrate 31 is a pentagon, four power supply terminals 62 may be provided in a given LED chip 20. In this case, a plurality of LED chips 20 may be connected to each other so that the LED chip assembly 20A is configured as a dodecahedron as a whole.

[0214] In addition, if Figure 20E As shown, when the planar shape of the substrate 31 is triangular, two power supply terminals 62 may be provided in a given LED chip 20. In this case, a plurality of LED chips 20 may be connected to form the LED chip assembly 20A as a whole into an icosahedron.

[0215] Furthermore, if Figure 20F As shown, when the planar shape of the substrate 31 is hexagonal or pentagonal, five power supply terminals 62 may be provided in a given LED chip 20 having a hexagonal planar shape of the substrate 31. In this case, a plurality of LED chips 20 may be connected to each other so that the LED chip assembly 20A as a whole forms a truncated icosahedron.

[0216] In addition, if Figure 21 As shown, when one LED chip 20 supplies power to other LED chips 20 adjacent in the X direction and to other LED chips 20 adjacent in the Y direction, power supply terminals 62 may be provided near all sides of the substrate 31. In this case, protrusions 31c may be provided on all sides of the substrate 31. Alternatively, the protrusions 31c may be formed by, for example, forming a U-shaped cutout or the like in the substrate 31 and folding back the power supply wiring 63 along with the substrate 31. In the illustrated example, the power supply terminals 62a of the power supply terminals 62 are formed on the protrusions 31c formed by folding back the substrate 31. In this case, the power supply terminals 62a may be folded back toward the front surface 31a of the substrate 31 or toward the back surface 31b of the substrate 31. In this manner, the power supply terminals 62 (and the power receiving terminals 61) may be folded back toward either the front surface 31a or the back surface 31b of the substrate 31.

[0217] In addition, Figure 21 In the example shown, only the positive (or negative) power supply terminal 62 is formed on the protrusion 31c formed by folding back the substrate 31, but the present invention is not limited thereto. Figure 22 As shown, the positive-side power supply terminal 62 and the negative-side power supply terminal 62 may be formed on a protruding portion 31 c formed by folding back the substrate 31 .

[0218] (Fourth Modification)

[0219] exist Figure 23 In the embodiment, the power receiving terminal 61 and the power supply terminal 62 can also be folded back toward the back surface 31b of the substrate 31. Figure 23In the example shown, the power receiving terminal 61 and the power supply terminal 62 are connectors. In this case, it is also possible to form a cutout portion on the substrate 31 and fold back the power receiving terminal 61 or the power supply terminal 62 together with the substrate 31. Thus, even when the power receiving terminal 61 and the power supply terminal 62 are constituted by relatively thick members such as connectors, it is possible to suppress the formation of large irregularities on the light emitting surface 20a. Therefore, it is possible to easily wind the LED sheet assembly 20A around the culture tube 10. In addition, in this case, the power receiving terminal 61 and the power supply terminal 62 may also be able to be folded back toward the front surface 31a side of the substrate 31. Thus, even when the power receiving terminal 61 and the power supply terminal 62 are constituted by relatively thick members such as connectors, it is possible to suppress the formation of large irregularities on the surface opposite to the light emitting surface 20a.

[0220] (Fifth modification example)

[0221] In Figure 24 , the display portion 25 is configured to be able to open and close. That is, the display portion 25 may be formed such that a U-shaped cutout portion is formed on the LED sheet 20 and the portion where the cutout portion is formed is bent to be exposed. Thus, usually the display portion 25 is covered by the LED sheet 20, so that it is possible to suppress light leakage from the LED sheet 20 to the outside of the culture tube 10 when irradiated to the culture tube 10. Therefore, it is possible to improve the light utilization efficiency. In addition, the shape of the cutout portion is not limited to a U shape, and may be a U shape, an L shape, a V shape, or the like.

[0222] In addition, as described above, the LED sheet assembly 20A disclosed in the above-described embodiment and each modification example can be folded. At this time, for example, as Figure 25A shown, the LED sheet assembly 20A may be folded in a so-called Z shape. In addition, as Figure 25B shown, the LED sheet assembly 20A may be folded in a so-called winding four-fold. In addition, as Figure 25C shown, the LED sheet assembly 20A may be folded in a so-called outer four-fold (W-fold). In addition, as Figure 25D shown, the LED sheet assembly 20A may be folded in a so-called winding three-fold. In addition, as Figure 25E shown, the LED sheet assembly 20A may be folded in a so-called cross-fold. Moreover, as Figure 25F shown, the LED sheet assembly 20A may be folded by a so-called Miura fold (registered trademark) that folds along a zigzag mountain fold portion (refer to the solid line) and valley fold portion (refer to the dotted line). In addition, the LED sheet assembly 20A may be folded along the connection portion between the LED sheets 20, or may be folded in such a manner that creases are formed at portions other than the connection portion between the LED sheets 20.

[0223] In the above embodiment, the LED sheet assembly 20A is described as being used in the cultivation system 1 for cultivating algae, but the present invention is not limited thereto. For example, although not shown, the LED sheet assembly 20A may also be used in an animal and plant cultivation factory for cultivating animals and plants using artificial light.

[0224] It is also possible to appropriately combine a plurality of components disclosed in the above embodiment and each modified example as needed. Alternatively, it is also possible to delete some components from all the components disclosed in the above embodiment and each modified example.

Claims

1. An LED sheet, wherein: The LED sheet has: a substrate having a first surface and a second surface located on an opposite side of the first surface; a metal wiring portion located on the first surface of the substrate; a plurality of LED chips mounted on the metal wiring portion; a power receiving terminal connected to the metal wiring portion and used for receiving power when connected to other LED sheets; as well as The power supply terminal is connected to the metal wiring portion and is used to supply power when connecting to other LED sheets.

2. The LED sheet according to claim 1, wherein: The LED sheet further includes power supply wiring that connects the metal wiring portion to the power receiving terminal and the power supply terminal.

3. The LED sheet according to claim 2, wherein: The power supply wiring has a thickness of 18 μm or more and 100 μm or less, and a line width of 5 mm or more and 30 mm or less.

4. The LED sheet according to claim 1, wherein: The power receiving terminal and the power feeding terminal are conductive bodies, and at least a portion of the power receiving terminal and at least a portion of the power feeding terminal are exposed.

5. The LED sheet according to claim 1, wherein: The power receiving terminal and the power feeding terminal can be folded back toward the first surface side or the second surface side.

6. The LED sheet according to claim 1, wherein: The substrate includes a protruding portion protruding outward, and at least one of the power receiving terminal and the power feeding terminal is formed on the protruding portion.

7. The LED sheet according to claim 1, wherein: The LED sheet is provided with a display portion that displays an on state and an off state of the LED chip.

8. The LED sheet according to claim 1, wherein: The substrate is flexible.

9. The LED sheet according to claim 1, wherein: The planar shape of the substrate is a k-gon, where k is a natural number greater than 3. There are multiple power supply terminals. The power supply terminals are provided at positions corresponding to at least two of the k sides of the k-gon.

10. The LED sheet according to claim 9, wherein: The number of power supply terminals is k-1 or less. The power supply terminals are provided at positions corresponding to different sides among the k sides of the k-gon.

11. An LED sheet assembly, wherein: The LED sheet assembly comprises: a first LED sheet; and a second LED sheet connected to the first LED sheet, The first LED sheet and the second LED sheet are respectively the LED sheets according to any one of claims 1 to 10, The power supply terminals of the first LED sheet are connected to the power receiving terminals of the second LED sheet.

12. The LED sheet assembly according to claim 11, wherein: The power supply terminals of the first LED sheet and the power receiving terminals of the second LED sheet are connected in parallel.

13. The LED sheet assembly according to claim 11, wherein: The LED sheet assembly further includes a connecting member mounted on the first LED sheet and the second LED sheet. The power supply terminals of the first LED sheet and the power receiving terminals of the second LED sheet are connected to each other via the connection member.

14. The LED sheet assembly according to claim 11, wherein: The LED chip assembly further includes a connecting member mounted on the first LED chip and the second LED chip. The second LED sheet is connected to the first LED sheet via the connecting member.

15. The LED sheet assembly according to claim 11, wherein: The LED sheet assembly is foldable.

16. The LED sheet assembly according to claim 11, wherein: The power receiving terminal and the power feeding terminal are covered with an insulator.

17. A culture system, wherein: The culture system comprises: Culture tubes for culturing algae; and The LED sheet assembly according to claim 11, which covers the outer surface of the culture tube.

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