Culture system

Abstract

To provide culture systems that can increase the efficiency of light utilization.SOLUTION: Provided is a culture system 1 comprising a culture tube 10 for culturing algae and an LED lighting device 20A (an LED sheet 20) which is adhered to the culture tube with an adhesive member 50, the LED sheet covering the outer surface of the culture tube and having a flexible substrate film, a metal wiring portion on the substrate film, and a plurality of LED chips implemented on the metal wiring portion.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This disclosure relates to a culture system. [Background technology]

[0002] In recent years, algal biofuels have attracted attention as a renewable energy resource. There are two main methods for cultivating algae: the so-called open pond system and the so-called closed photobioreactor system. Of these, the closed photobioreactor system can suppress contamination of the culture medium compared to the open pond system. Furthermore, because the closed photobioreactor system can be used indoors year-round, it offers superior algal productivity. As a technology for cultivating algae using such a photobioreactor, for example, a technology has been disclosed in which light from a light-emitting diode is guided into the culture tank through an optical waveguide (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2012-183002 [Overview of the project] [Problems that the invention aims to solve]

[0004] This disclosure provides a culture system capable of increasing the efficiency of light utilization. [Means for solving the problem]

[0005] The culture system according to this embodiment is a culture system comprising a culture tube for culturing algae and an LED lighting device that covers the outer surface of the culture tube.

[0006] In the culture system according to this embodiment, the LED lighting device may be an LED sheet.

[0007] In the culture system according to the present embodiment, the LED sheet may include a flexible substrate film, a metal wiring portion on the substrate film, and a plurality of LED chips mounted on the metal wiring portion.

[0008] In the culture system according to the present embodiment, the surface of the substrate film may face the culture tube and be colored white.

[0009] In the culture system according to the present embodiment, a display unit for displaying the ON state and the OFF state of the LED chip may be provided on the LED sheet.

[0010] In the culture system according to the present embodiment, the LED lighting device includes an LED bar light including a plurality of LED chips and a reflection sheet attached to the LED bar light, and the LED bar light may be provided between the culture tube and the reflection sheet.

[0011] In the culture system according to the present embodiment, the LED sheet may be adhered to the culture tube by an adhesive member.

[0012] In the culture system according to the present embodiment, the peel strength between the LED sheet and the culture tube may be 3 N / 15 mm or more and 30 N / 15 mm or less.

[0013] In the culture system according to the present embodiment, the reflection sheet may be adhered to the culture tube by an adhesive member.

[0014] In the culture system according to the present embodiment, the refractive index of the adhesive member may be 1.48 or more and 1.60 or less.

[0015] In the culture system according to the present embodiment, the surface of the adhesive member faces the culture tube, and recesses formed in a mesh pattern may be formed on the surface of the adhesive member.

[0016] In the culture system according to the present embodiment, the adhesive member may contain ethylene vinyl acetate or polyvinyl butyral.

[0017] In the culture system according to the present embodiment, when the molar absorption coefficient of the culture solution in the culture tube is ε (L·cm

[0018] , [Figure 7] ·g -1 ), the molar concentration of the culture solution is C (g·L -1 ), and the inner diameter or inner width of the culture tube is D (cm), the photosynthetic photon flux density I0 of the LED lighting device is 250 / 10 (-εCD / 2) ≦I0≦250 / 10 (-εCD) and may satisfy the relationship.

Advantages of the Invention

[0018] According to the present embodiment, the utilization efficiency of light can be improved.

Brief Description of the Drawings

[0019] [Figure 1] FIG. 1 is a perspective view showing a culture system according to an embodiment. <​​​​​​​​​​​​​​​Figure 7 is a cross-sectional view (cross-sectional view along line VII-VII in Figure 4) showing the LED sheet of a culture system according to one embodiment. [Figure 8] Figure 8 is a plan view showing the adhesive member of a culture system according to one embodiment. [Figure 9] Figures 9(a)-(h) are cross-sectional views showing a method for manufacturing an LED sheet in a culture system according to one embodiment. [Figure 10] Figure 10 is a schematic perspective view showing an example of the use of a culture system according to one embodiment. [Figure 11] Figure 11 is a schematic perspective view showing an example of the use of a culture system according to one embodiment. [Figure 12] Figure 12 is a perspective view showing a first modified example of a culture system according to one embodiment. [Figure 13] Figure 13 is a cross-sectional view (cross-sectional view along line XIII-XIII in Figure 12) showing a first modified example of the culture system according to one embodiment. [Figure 14] Figure 14 is a perspective view showing a second modified example of a culture system according to one embodiment. [Figure 15] Figure 15 is a perspective view showing a third modified example of a culture system according to one embodiment. [Modes for carrying out the invention]

[0020] The culture system according to this embodiment includes culture tubes for culturing algae and an LED sheet wrapped around the culture tubes. By wrapping the LED sheet around the culture tubes, it is possible to suppress the leakage of light irradiated from the LED sheet onto the culture tubes to the outside of the culture tubes.

[0021] The LED sheet in the culture system according to this embodiment is a sheet-shaped LED lighting device equipped with a flexible substrate film. Therefore, the weight of the culture system can be reduced. Furthermore, the LED sheet in the culture system according to this embodiment can be thinner overall than a straight-tube type LED bar light with multiple LEDs arranged in a single array. This reduces the bulkiness of the culture system when the LED sheet is wrapped around the culture tube, thereby reducing the installation space required for the culture system.

[0022] Furthermore, because the LED sheet is a sheet-shaped LED lighting device equipped with a flexible substrate film, the LED sheet can be easily attached to culture tubes of various shapes.

[0023] Hereinafter, one embodiment will be described in detail with reference to the drawings. The following figures are schematic representations. Therefore, the size and shape of each part are exaggerated as appropriate to facilitate understanding. Furthermore, it is possible to modify and implement the design as appropriate without departing from the technical concept. In the following figures, the same parts are denoted by the same reference numerals, and some detailed explanations may be omitted. In addition, the numerical values ​​such as dimensions and material names of each component described in this specification are examples of embodiments and are not limited to these; they can be selected and used as appropriate. In this specification, terms that specify shapes and geometric conditions, such as parallel, orthogonal, and perpendicular, will be interpreted to include not only their strict meaning but also substantially the same state. In this specification, "upper" and "lower" refer to the upper and lower parts, respectively, when the culture tube is in an upright position (Figures 1 and 2).

[0024] (Culture system) As shown in Figures 1 and 2, the culture system 1 comprises a culture tube 10 for culturing algae and an LED lighting device 20A covering the outer surface of the culture tube 10. In this embodiment, the LED lighting device 20A is an LED sheet 20. A control unit 40 is electrically connected to the LED sheet 20.

[0025] The culture tube 10 comprises a hollow body portion 11, a bottom portion 12 located below the body portion 11, and a lid portion 13 located above the body portion 11. The body portion 11 has a cylindrical shape. However, the body portion 11 may also have a polygonal cylindrical shape, such as a square or octagonal shape.

[0026] The base portion 12 is circular in plan view and is connected to the lower end of the body portion 11. The base portion 12 may be molded integrally with the body portion 11, or it may be detachably attached to the body portion 11. The planar shape of the base portion 12 may be elliptical, quadrilateral, or other polygonal shapes.

[0027] The lid portion 13 is circular in plan view and is connected to the upper end of the body portion 11. This lid portion 13 may be detachably attached to the body portion 11. The planar shape of the bottom portion 12 may be elliptical or polygonal, such as a quadrilateral.

[0028] The culture tube 10 is filled with culture medium CS. The materials used to construct the culture tube 10 may include, for example, glass (refractive index: approximately 1.55), polycarbonate (refractive index: approximately 1.58), or resin materials such as acrylic.

[0029] The LED sheet 20 is wrapped around the culture tube 10 so that its light-emitting surface 20a faces the culture tube 10. The LED sheet 20 covers the body 11 of the culture tube 10. Preferably, the LED sheet 20 covers the entire body 11 of the culture tube 10 in the circumferential direction. This allows light to be irradiated into the culture tube 10 from all sides of the body 11. This can increase the efficiency of algae growth. Furthermore, preferably, the LED sheet 20 covers the entire body 11 of the culture tube 10 in the longitudinal direction. This can further increase the efficiency of light utilization.

[0030] In this configuration, the LED sheet 20 may be provided with a display unit 25 that displays the ON state and the OFF state of the LED chip 21, which will be described later. This makes it easy to check the ON and OFF states of the LED chip 21 even when the LED sheet 20 is wrapped around the culture tube 10. In this embodiment, the display unit 25 is a through-hole that penetrates the LED sheet 20. In this case, when the LED chip 21 is lit, a small amount of light leaks from the display unit 25. On the other hand, when the LED chip 21 is not lit, no light leaks from the display unit 25. In this way, the ON and OFF states of the LED chip 21 can be easily checked.

[0031] In the illustrated example, 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. Furthermore, multiple through-holes may be formed. For example, one through-hole may be formed near each LED chip 21. This makes it easy to identify damaged LED chips 21.

[0032] Next, the LED sheet 20 will be described in detail. As shown in Figures 3 and 4, the LED sheet 20 is a so-called single-sided light-emitting, planar light source sheet. Multiple LED chips 21 are arranged on the light-emitting surface 20a side of this LED sheet 20. By using such a direct-lit LED sheet 20, the light emitted from the LED chips 21 passes directly through the light-emitting surface 20a. This allows for a stronger light intensity, promoting the cultivation of algae. Furthermore, since the LED sheet 20 can be made thinner overall than an LED bar light, the occurrence of shadows on the sides of the LED chips 21 can be suppressed.

[0033] The LED sheet 20 in Figure 4 comprises a flexible wiring board 30 and a plurality of LED chips 21 regularly arranged on the flexible wiring board 30. By using such a flexible wiring board 30, an LED sheet 20 with a relatively large surface area can be obtained. An LED sheet 20 with a relatively large surface area can reduce the number of LED sheets 20 used, thereby suppressing variations in light intensity that may occur when arranging multiple LED sheets 20. Note that in Figure 4, the light-reflective insulating protective film 34 and the transparent protective film 35, which will be described later, are not shown.

[0034] In this case, the LED chips 21 are arranged in a grid pattern in a plan view within the flexible wiring board 30. That is, the LED chips 21 are arranged in a matrix with multiple rows and columns, and there are N columns R of M LED chips 21 connected in series.

[0035] For example, in Figure 4, 14 LED chips (M=14) are connected in series along the first arrangement direction (X direction) of the LED chips 21. Furthermore, 10 rows (N=10) of this row R, each containing 14 LED chips 21, are arranged in parallel along the second arrangement direction (Y direction) of the LED chips 21. Note that the number of LED chips 21 is not limited to this. Specifically, it is preferable that 10 to 14 LED chips 21 (14≧M≧10) are arranged in series along the first arrangement direction (X direction), and that this row R is arranged in parallel with 4 to 10 rows (10≧N≧4) along the second arrangement direction (Y direction) of the LED chips 21. By arranging 10 or more LED chips 21 in series, the spacing between LED chips 21 in the first arrangement direction (X direction) can be shortened. This suppresses in-plane variation in the illuminance of the LED sheet 20. Therefore, it is possible to suppress variations in the light irradiated onto the culture tube 10. Furthermore, power consumption can be reduced by arranging 14 or fewer LED chips 21 in series. Also, by arranging 4 or more rows of LED chips 21 in parallel in the second arrangement direction (Y direction) of the LED chips 21, damage to a specific LED chip 21 can be prevented from spreading to LED chips 21 in other rows. This prevents an extreme decrease in the overall illumination of the LED sheet 20. However, in the case of a direct-lit LED sheet 20, there is a higher possibility that workers will come into contact with the LED chips 21 when installing or removing the LED sheet 20. If a worker accidentally comes into strong contact with an LED chip 21, there is a higher risk of damage to the LED chip 21. Therefore, taking measures to deal with damage to the LED chips 21 is important from a risk management perspective. Furthermore, power consumption can be reduced by arranging 10 or fewer rows of LED chips 21 in parallel.

[0036] The LED sheet 20 has multiple metal wiring sections 22, which are arranged along a first arrangement direction (X direction). Each of the multiple metal wiring sections 22 arranged along the first arrangement direction (X direction) corresponds to each row R of the LED chip 21. Each LED chip 21 is positioned so as to straddle a pair of adjacent metal wiring sections 22 in the X direction. In addition, each terminal of the LED chip 21 (not shown) is electrically connected to a pair of metal wiring sections 22. The multiple metal wiring sections 22 constitute a power supply section for the LED chip 21, and when power is supplied to the multiple metal wiring sections 22, all the LED chips 21 arranged in the row R light up. The multiple metal wiring sections 22 also constitute a part of the metal wiring section 32, which will be described later.

[0037] The spacing Px between LED chips 21 in the first arrangement direction (X direction) is preferably 37 mm or more and 50 mm or less. Furthermore, the spacing Py between LED chips 21 in the second arrangement direction (Y direction) is preferably 37 mm or more and 100 mm or less. By setting the spacing between LED chips 21 within the above ranges, the brightness of the LED sheet 20 can be made uniform across the surface. This suppresses variations in the light illuminating the space and reduces the power consumption of the LED sheet 20.

[0038] The thickness of the thickest part of the LED sheet 20 is preferably 5 mm or less. By making the LED sheet 20 thinner in this way, it is possible to suppress the bulkiness of the LED sheet 20 when it is attached to the culture tube 10. This makes it possible to easily attach the LED sheet 20 to the culture tube 10 even in a limited space.

[0039] The arrangement of the LED chips 21 is not limited to a grid pattern in plan view, but may also be arranged in a staggered pattern in plan view, as shown in Figure 5(a). Furthermore, the LED chips 21 do not need to be uniformly arranged within the plane of the LED sheet 20. For example, the density of LED chips 21 may be higher at the periphery of the LED sheet 20. Specifically, as shown in Figure 5(b), the LED chips 21 may be arranged in a grid pattern in the central part of the LED sheet 20 (lower part of Figure 5(b)) and in a staggered pattern at the periphery of the LED sheet 20 (upper part of Figure 5(b)). This suppresses the decrease in brightness of the LED sheet 20 at the periphery, makes the brightness of the LED sheet 20 uniform within the plane, and suppresses the variation in light illuminating space.

[0040] The overall shape of the LED sheet 20 is rectangular in plan view, but there are no particular limitations on the size or planar shape of the LED sheet 20. Because the LED sheet 20 offers a high degree of freedom in size and shape processing, it can flexibly respond to various needs in this regard. Furthermore, because the LED sheet 20 is flexible, it can be installed not only on flat mounting surfaces but also on mounting surfaces of various shapes.

[0041] In Figure 4, the length Lx of the LED sheet 20 in the first arrangement direction (X direction) is preferably 500 mm or more and 700 mm or less, and more preferably 550 mm or more and 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 and 500 mm or less, and more preferably 350 mm or more and 450 mm or less. By ensuring that the size of each LED sheet 20 is not excessively small, the amount of light emitted from the LED sheet 20 can be increased. Also, by ensuring that the size of each LED sheet 20 is not excessively large, the impact on other LED chips 21 when a particular LED chip 21 is damaged can be minimized. Therefore, it is possible to prevent an extreme decrease in the overall illuminance of the LED sheet 20 and to limit the range in which the illuminance decreases.

[0042] Next, the control unit 40 will be described. As shown in Figure 3, the control unit 40 supplies power to the LED sheet 20 and controls the illumination of the LED sheet 20. The control unit 40 is detachably connected to the LED sheet 20 via a first connector 44A provided on the LED sheet 20. In other words, the control unit 40 is configured separately from the LED sheet 20 and is connected to the LED sheet 20 externally. To put it another way, the control unit 40 is not integrated with the LED sheet 20. This allows the control unit 40 to be separated from the LED sheet 20 and installed in any location. Therefore, the LED sheet 20 can be easily attached to the culture tube 10 even in a limited space.

[0043] 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 100V and 240V. The AC / DC converter 42 converts the AC voltage of 100V to 240V into a constant voltage (for example, 44V) DC voltage. The PWM control unit 43 adjusts the brightness of the LED chips 21 of the LED sheet 20 by arbitrarily changing 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 via the first connector 44A.

[0044] In this embodiment, a constant DC voltage is applied to the LED sheet 20 from the PWM control unit 43 of the control unit 40. This makes it possible to dim the LED chip 21, unlike when a rectified pulse voltage is applied directly to the LED sheet 20. That is, the PWM control unit 43 can arbitrarily control the illuminance of the LED chip 21 by appropriately changing the duty cycle of the DC voltage from the AC / DC converter 42. For example, as shown in Figure 6(a), the PWM control unit 43 can reduce the illuminance of the LED chip 21 by reducing the duty cycle of the constant voltage from the AC / DC converter 42 from 100% (solid line) to 50% (dotted line).

[0045] When adjusting the illuminance of the LED chip 21 in this way, for example, the illuminance of the LED sheet 20 may be adjusted according to the growth stage of the algae. This allows for adjustment of the algal growth rate. For example, in the early stages of growth when the algae are small, the illuminance of the LED sheet 20 may be lowered, and in the later stages of growth when the algae are larger and growing profusely in the culture tube 10, the illuminance of the LED sheet 20 may be increased. Another example of adjusting the illuminance of the LED sheet 20 is to increase the illuminance for types of algae that require high illuminance, and to lower the illuminance for types of algae that can be grown at low illuminance. Also, the illuminance may be increased to expedite the shipping period, and decreased to delay the shipping period.

[0046] Furthermore, by applying a constant DC voltage to the LED sheet 20 from the PWM control unit 43, the integrated light output per unit time from the LED sheet 20 can be increased. That is, for example, the integrated light output when a constant DC voltage is applied to the LED sheet 20 (area of ​​the shaded portion in Figure 6(a)) can be made larger than the integrated light output when a pulsed voltage is applied (area of ​​the shaded portion in Figure 6(b)), as a comparative example. This increases the luminescence efficiency of the light from the LED sheet 20 and improves the efficiency of algae growth.

[0047] Referring again to Figure 3, the LED sheet 20 is equipped with regulators 45. In this case, a regulator 45 is provided for each row of LED chips 21, specifically, 10 regulators 45 are provided for each of the 10 rows of LED chips 21. These regulators 45 play the role of maintaining a constant current flowing through the multiple LED chips 21 in each row. This prevents excessive current from flowing to the LED chips 21 in other rows even if one LED chip 21 is damaged, thus preventing damage to the LED chips 21 in other rows. As a result, it is possible to prevent an extreme decrease in the overall illuminance of the LED sheet 20 and suppress variations in the light illuminating the space.

[0048] Furthermore, the LED sheet 20 is provided with a power supply line 46 branching from the first connector 44A. A second connector 44B is also provided on the LED sheet 20. The power supply line 46 is not electrically connected to the LED chips 21 of the LED sheet 20, but is electrically connected to the wiring of another LED sheet 200 having the same configuration as the LED sheet 20. That is, the power supply line 46 is detachably connected to the wiring of the LED sheet 200 via the second connector 44B and another first connector 44A provided on the other LED sheet 200. Current from the power supply line 46 is supplied to the other LED sheet 200 via the second connector 44B and the other first connector 44A. This allows two LED sheets 20, 200 to be linked and simultaneously controlled by a single control unit 40. By enabling the simultaneous control of multiple LED sheets 20, 200 by a single control unit 40, the number of control units 40 can be reduced, thus preventing the culture system 1 from becoming bulky. Therefore, the culture system 1 can be easily installed even in a limited space.

[0049] (Each component of the LED sheet) Next, the components constituting the LED sheet 20 will be described. As shown in Figure 7, the LED sheet 20 comprises a flexible wiring board 30 and a plurality of LED chips 21 arranged on the flexible wiring board 30. The flexible wiring board 30 has a flexible substrate film 31 and a metal wiring portion 32 on the substrate film 31. The metal wiring portion 32 is laminated to the substrate film 31 via an adhesive layer 33.

[0050] Each LED chip 21 is mounted in a manner that allows it to conduct electricity to the metal wiring section 32. In this LED sheet 20, since the LED chips 21 are mounted on the flexible wiring board 30, it is possible to arrange multiple LED chips 21 at a desired high density.

[0051] 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 area of ​​the LED sheet 20 where the LED chip 21, regulator 45, first connector 44A, or second connector 44B are provided. Furthermore, the light-reflective insulating protective film 34 is not formed in the peripheral area of ​​the area where the LED chip 21, regulator 45, first connector 44A, or second connector 44B are provided. The light-reflective insulating protective film 34 is a layer that combines an insulating function that contributes to improving the migration resistance characteristics of the LED sheet 20 and a light-reflecting function that contributes to improving the light environment created by the LED sheet 20. This layer is formed from an insulating resin composition containing a white pigment. If the aforementioned metal wiring portion 32 and the transparent protective film 35 described later provide the necessary migration resistance and light-reflecting functions, the light-reflective insulating protective film 34 does not need to be formed on the metal wiring portion 32.

[0052] Furthermore, 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 resinous film formed on the outermost surface (the surface closest to the light-emitting surface 20a) of the LED sheet 20, primarily to ensure the waterproofness of the LED sheet 20.

[0053] Furthermore, a solder joint 36 is provided on the metal wiring section 32. Each LED chip 21 is electrically connected to the metal wiring section 32 via the solder joint 36.

[0054] (Substrate film) The substrate film 31 can be a flexible resin film. In this specification, "flexible" means "having a radius of curvature of at least 1 m, preferably 50 cm, more preferably 30 cm, even more preferably 10 cm, and particularly preferably 5 cm when bent."

[0055] As the material for the substrate film 31, a thermoplastic resin with high heat resistance and insulation properties may be used. As such a resin, polyimide resin (PI) or polyethylene naphthalate (PEN), which has excellent heat resistance, dimensional stability when heated, mechanical strength, and durability, can be used. Among these, polyethylene naphthalate (PEN) whose heat resistance and dimensional stability have been improved by heat resistance improvement treatment such as annealing is preferably used. Alternatively, polyethylene terephthalate (PET) whose flame retardancy has been improved by adding flame-retardant inorganic fillers may also be used.

[0056] The surface 31a of the substrate film 31 faces the culture tube 10. Preferably, this surface 31a is colored white. This effectively reflects light leaking out from the culture tube 10, further improving the efficiency of light utilization.

[0057] The thickness of the substrate film 31 is not particularly limited. From the viewpoint of not becoming a bottleneck in the heat dissipation path, having heat resistance and insulation properties, and balancing manufacturing costs, the thickness of the substrate film 31 is preferably between 10 μm and 500 μm, more preferably between 50 μm and 250 μm. Furthermore, from the viewpoint of maintaining good productivity when manufacturing by a roll-to-roll method, it is also preferable that the thickness of the substrate film 31 be within the above thickness range.

[0058] (adhesive layer) The adhesive forming the adhesive layer 33 may be any known resin-based adhesive. Among these resin adhesives, urethane-based, polycarbonate-based, silicone-based, ester-based, or epoxy-based adhesives are particularly preferred.

[0059] (Metal wiring part) The metal wiring section 32 is a wiring pattern formed on the surface 31a (the surface on the light-emitting surface 20a side) of the substrate film 31 using a conductive substrate such as metal foil. Preferably, the metal wiring section 32 is formed on the surface 31a of the substrate film 31 via an adhesive layer 33 by a dry lamination method. The metal wiring section 32 includes a plurality of metal wiring sections 22 as described above. The plurality of metal wiring sections 22 include a first metal wiring section 22A and a second metal wiring section 22B spaced apart from the first metal wiring section 22A. LED chips 21 are mounted on the first metal wiring section 22A and the second metal wiring section 22B, and the LED chips 21 are electrically connected to the first metal wiring section 22A and the second metal wiring section 22B. The LED chips 21 light up when power is supplied to the first metal wiring section 22A and the second metal wiring section 22B.

[0060] The metal wiring section 32 preferably achieves a high level of both heat dissipation and electrical conductivity, and for example, copper foil can be used. In this case, heat dissipation from the LED chip 21 is stable and an increase in electrical resistance is prevented, so the variation in light emission between LED chips 21 is reduced and stable light emission is possible. The lifespan of the LED chip 21 is also extended. Furthermore, deterioration of surrounding materials such as the substrate film 31 due to heat is prevented, so the product lifespan of the LED sheet 20 can also be extended. Examples of metals that can form the metal wiring section 32 include, in addition to the above-mentioned copper, aluminum, gold, silver, and other metals.

[0061] The thickness of the metal wiring section 32 can be appropriately set according to the current resistance required for the flexible wiring board 30. However, in order to suppress warping due to thermal shrinkage of the substrate film 31 during soldering by reflow soldering, etc., it is preferable that the thickness of the metal wiring section 32 be 10 μm or more. On the other hand, it is preferable that the thickness of the metal wiring section 32 be 50 μm or less, which allows for sufficient flexibility of the flexible wiring board 30 and prevents a decrease in handling performance due to increased weight.

[0062] (Soldering section) The solder joint 36 connects the metal wiring section 32 to the LED chip 21. This soldering can be performed using either a reflow soldering method or a laser soldering method.

[0063] (LED chip) The LED chip 21 is a light-emitting element that utilizes light emission at the PN junction where a P-type semiconductor and an N-type semiconductor are joined. 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 it may have a structure in which both a P-type electrode and an N-type electrode are provided on one side of the element.

[0064] Furthermore, it is preferable to select an LED chip 21 with high luminous efficiency. Specifically, it is preferable to use an LED chip 21 with a luminous efficiency of 150 lm / W or more, and even more preferable to use one with a luminous efficiency of 180 lm / W or more. By increasing the luminous efficiency of the LED chip 21 to 150 lm / W or more, the number (density) of LED chips 21 to be mounted can be reduced, the heat generated by Joule heating from the LED chip 21 can be reduced, and the deterioration of surrounding materials such as the substrate film 31 due to heat from the LED chip 21 can be prevented.

[0065] As described above, the LED sheet 20 directly mounts the LED chips 21 onto a metal wiring section 32 that exhibits high heat dissipation. This allows excess heat generated when the LED chips 21 are lit to be quickly dissipated through the metal wiring section 32, even when the LED chips 21 are arranged at high density. As a result, sufficient heat can be dissipated to the outside of the LED sheet 20 via the substrate film 31, preventing deterioration of the substrate film 31 and other surrounding components due to heat from the LED chips 21.

[0066] (Light-reflective insulating protective film) As shown in Figure 7, the light-reflective insulating protective film 34 is a layer formed in the region excluding the area where the LED chip 21 is provided and its surrounding area. This light-reflective insulating protective film 34 is a so-called resist layer that improves the migration resistance characteristics of the flexible wiring substrate 30 by having sufficient insulating properties, and is also a light-reflective layer that contributes to improving the luminous brightness of the light environment created by the LED sheet 20.

[0067] The light-reflective insulating protective film 34 can be formed from various resin compositions that use a urethane-based resin or the like as a base resin and further contain a white pigment made of an inorganic filler such as titanium dioxide. As the base resin of the resin composition used to form the light-reflective insulating protective film 34, in addition to urethane-based resins, acrylic polyurethane resins, polyester resins, phenolic resins, etc. can be used as appropriate. It is more preferable that the base resin of the resin composition for forming the light-reflective insulating protective film 34 be the same as or of the same type as the resin used for forming the transparent protective film 35. As will be described later, it is preferable to use an acrylic polyurethane resin as the main material resin for the transparent protective film 35. Therefore, if the base resin of the resin composition for forming the transparent protective film 35 is an acrylic polyurethane resin, it is more preferable that the base resin of the resin composition for forming the light-reflective insulating protective film 34 be a urethane-based resin or an acrylic polyurethane resin.

[0068] As an inorganic filler to be included as a white pigment in the resin composition that forms the light-reflective insulating protective film 34, in addition to titanium dioxide, at least one selected from alumina, barium sulfate, magnesia, 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.

[0069] The thickness of the light-reflective insulating protective film 34 is 5 μm or more and 50 μm or less, more preferably 7 μm or more and 20 μm or less. By having a thickness of 5 μm or more of the light-reflective insulating protective film 34, it is possible to suppress the thinning of the light-reflective insulating protective film 34, especially at the edges of the metal wiring portion 32. Therefore, it is possible to suppress the exposure of the metal wiring portion 32. Furthermore, by having a thickness of 50 μm or less of the light-reflective insulating protective film 34, it is possible to suppress the peeling of the light-reflective insulating protective film 34 from, for example, the metal wiring portion 32, even if the flexible wiring substrate 30 is bent during transport or the like.

[0070] Furthermore, the light-reflective insulating protective film 34 preferably has a light reflectance of 65% or more, more preferably 70% or more, and even more preferably 80% or more at wavelengths of 400 nm to 780 nm. The LED sheet 20 can be made to have a light reflectance of 75% or more when the thickness of the light-reflective insulating protective film 34 is 8 μm by, for example, including 20 parts by mass or more of titanium dioxide per 100 parts by mass of a urethane-based or acrylic-based polyurethane base resin.

[0071] (Transparent protective film) The transparent protective film 35 is formed on the outermost surface of the LED sheet 20 so as to cover the LED chip 21. The transparent protective film 35 is waterproof and transparent. The waterproof nature of the transparent protective film 35 prevents water from entering the inside of the LED sheet 20. If a high-luminosity LED chip 21 is selected, for example, one with a luminous efficiency of 150 lm / W or more, the impact on the LED sheet 20 will be greater if a specific LED chip 21 is damaged. Therefore, it is important from a risk management perspective to make the LED chip 21 as undamaged as possible.

[0072] The transparent protective film 35 can be formed from various resin compositions using acrylic polyurethane resin or the like as the base resin. As the base resin for the resin composition used to form the transparent protective film 35, in addition to acrylic polyurethane resin, urethane resin, polyester resin, phenolic resin, etc., can be used as appropriate. It is more preferable that the base resin for the resin composition forming the transparent protective film 35 be the same as or of the same type as the resin used for the resin composition forming the light-reflective insulating protective film 34. A preferred specific combination is one in which the base resin for the resin composition forming the light-reflective insulating protective film 34 is a urethane resin, and the resin forming the transparent protective film 35 is an acrylic polyurethane resin.

[0073] The thickness of the transparent protective film 35 is 10 μm or more and 40 μm or less, preferably 15 μm or more and 30 μm or less, and more preferably 20 μm or more and 25 μm or less. By setting the thickness of the transparent protective film 35 within the above range, the good flexibility, thinness, lightness, and good optical properties required in emergencies of the LED sheet 20 can be maintained. In addition, sufficient waterproofing required in emergencies can be provided to the LED sheet 20.

[0074] The water resistance of the LED sheet 20 with the transparent protective film 35 is not particularly limited, as long as it is sufficient to suppress the degradation of the LED chips 21 when water is sprayed onto the LED sheet 20. Such water resistance is preferably IPX4 or higher according to the waterproof and dustproof protection standards set by the IEC (International Electrotechnical Commission). IPX4 or higher waterproofing means that the LED chips 21 are not adversely affected by water splashes from any direction. Specifically, this means that when water is sprayed from a spray nozzle at a rate of 10 L / min over the entire range of ±180° relative to the normal direction of the LED sheet 20 for 5 minutes, the LED chips 21 are not adversely affected.

[0075] Incidentally, as shown in Figures 1 and 2, in this embodiment, the LED sheet 20 is attached to the culture tube 10 by an adhesive member 50. This prevents the interposition of an air layer between the LED sheet 20 and the culture tube 10. If an air layer is interposed between the LED sheet 20 and the culture tube 10, the light from the LED chip 21 is reflected off the outer surface of the culture tube 10 due to the difference in refractive index between the air and the culture tube 10. As a result, the light reflectivity increases, which may reduce the light utilization efficiency in the culture system 1. In contrast, in this embodiment, the interposition of an air layer between the LED sheet 20 and the culture tube 10 can be prevented. Therefore, the reflection of light from the LED chip 21 off the outer surface of the culture tube 10 can be prevented. As a result, the light utilization efficiency can be further increased. In this embodiment, the adhesive member 50 is provided so as to cover the entire light-emitting surface 20a of the LED sheet 20.

[0076] The adhesive member 50 preferably contains ethylene vinyl acetate or polyvinyl butyral. The adhesive member 50 may also contain an adhesive. This adhesive is not particularly limited and can include, for example, natural rubber-based adhesives, butyl rubber, polyisoprene, polyisobutylene, polychloroprene, styrene-based polymers, silicone-based resins, acrylic-based resins, polyvinyl acetate, vinyl acetate-based resins such as ethylene-vinyl acetate copolymers, urethane-based resins, acrylonitrile, hydrocarbon resins, alkylphenol resins, rosin, rosin triglycerides, and rosin-based resins such as hydrogenated rosin. The adhesive member 50 may also be a commercially available double-sided adhesive film.

[0077] The refractive index of the adhesive member 50 may be between 1.48 and 1.60, between 1.50 and 1.58, or between 1.51 and 1.56. As mentioned above, the culture tube 10 is made of, for example, glass (refractive index: approximately 1.55) or polycarbonate (refractive index: approximately 1.58). Therefore, by setting the refractive index of the adhesive member 50 to between 1.48 and 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. This suppresses the reflection of light from the LED chip 21 on the outer surface of the culture tube 10. As a result, the efficiency of light utilization can be further increased. The refractive indices of the adhesive member 50 and the culture tube 10 can be measured, for example, by a refractometer (Abbe refractometer, DR-A1 (product name) manufactured by Atago Co., Ltd.).

[0078] As shown in Figure 2, the surface 51 of the adhesive member 50 faces the culture tube 10. Also, as shown in Figure 8, a mesh-like structure of recesses 52 is formed on this surface 51. These recesses 52 serve as an air venting mechanism to remove air interposed between the adhesive member 50 and the culture tube 10.

[0079] 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 described above. In the illustrated example, the spacing between the first portions 52a is equal. The first portions 52a may extend in a direction inclined with respect to the X direction. The spacing between the first portions 52a may also be different.

[0080] Each second portion 52b extends along the second arrangement direction (Y direction) of the LED chip 21 described above. In the illustrated example, the spacing between the second portions 52b is equal. The second portions 52b may extend in a direction inclined with respect to the Y direction. The spacing between the second portions 52b may also be different.

[0081] The peel strength between the LED sheet 20 and the culture tube 10 is preferably 3N / 15mm or more and 30N / 15mm or less, more preferably 4N / 15mm or more and 20N / 15mm or less, and even more preferably 5N / 15mm or more and 15N / 15mm or less. A peel strength of 3N / 15mm or more between the LED sheet 20 and the culture tube 10 prevents the LED sheet 20 from peeling off the culture tube 10 during use. Furthermore, a peel strength of 30N / 15mm or less prevents, for example, a part of the adhesive member 50 from adhering to the culture tube 10 when the LED sheet 20 is peeled off the culture tube 10. In addition, a peel strength of 30N / 15mm or less between the LED sheet 20 and the culture tube 10 makes it easier to peel the LED sheet 20 off 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, for example, using a material testing machine (Tensilon Universal Material Tester RTF-2325 (product name) manufactured by A&D Company, Limited).

[0082] In addition, the photosynthetic photon flux density (PPFD) I0 of the LED sheet 20 should be 250 μmol / m -2 ·s -1 or more in any region within the culture tube 10. When the photosynthetic photon flux density I0 of the LED sheet 20 is 250 μmol / m -2 ·s -1 or more, the growth efficiency of algae can be improved. Note that the PPFD can be measured by a measuring device such as a quantum meter (e.g., the quantum sensor LI-190R and the light meter LI-250A manufactured by LI-COR, USA).

[0083] Here, when 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 C (g·L -1 ), and the inner diameter d1 of the culture tube 10 (see Fig. 1) is D (cm), the photosynthetic photon flux density I0 of the LED sheet 20 is 250 / 10 (-εCD / 2) ≦I0≦250 / 10 (-εCD) preferably satisfying the relationship. This can improve the growth efficiency of algae and reduce power consumption.

[0084] By the way, when the absorbance is A and the transmittance is T, according to the Lambert-Beer law, the following formula (1) holds. A = -log 10 T = εCD ··· formula (1) In addition, when the photosynthetic photon flux density transmitted through the culture solution CS is I, the transmittance T can be expressed by the following formula (2). T = I / I0 ··· formula (2) Therefore, from formulas (1) and (2), the photosynthetic photon flux density I0 can be expressed by the following formula (3). I0 = I / 10 -εCD ··· formula (3)

[0085] As described above, the photosynthetic photon flux density I0 of the LED sheet 20 is 250 μmol / m² in any region within the culture tube 10. -2 ·s -1 It is preferable that the above conditions are met. Furthermore, it is considered that the position where the photosynthetic photon flux density I0 of the LED sheet 20 is lowest within the culture tube 10 is the radial center of the culture tube 10. For this reason, the photosynthetic photon flux density I0 of the LED sheet 20 is 250 μmol / m² at the radial center of the culture tube 10. -2 ·s -1 It is preferable that the above conditions are met. In this case, 250 / 10 (-εCD / 2) ≤I0 By satisfying this relationship, the photosynthetic photon flux density I0 of the LED sheet 20 is set to 250 μmol / m² in the radial center of the culture tube 10. -2 ·s -1 It can be set to the above. Therefore, 250 / 10 (-εCD / 2) By satisfying the relationship ≤ I0, the efficiency of algae growth can be improved. Also, I0 ≤ 250 / 10 (-εCD) By satisfying this relationship, power consumption can be reduced.

[0086] (How to manufacture LED sheets) Next, the method for manufacturing the LED sheet 20 according to this embodiment will be described with reference to Figures 9(a)-(h).

[0087] First, a substrate film 31 is prepared (Figure 9(a)). Next, a metal foil 32A, such as copper foil, which will be the material for the metal wiring portion 32, is laminated onto the surface 31a of the substrate film 31 (see Figure 7) (Figure 9(b)). The metal foil 32A is bonded to the surface 31a of the substrate film 31 by an adhesive layer 33, such as a urethane-based adhesive. Alternatively, the metal foil 32A may be directly formed on the surface 31a of the substrate film 31 by an electrolytic plating method or a vapor deposition method (sputtering, ion plating, electron beam deposition, vacuum deposition, chemical deposition, etc.). Alternatively, the substrate film 31 may be directly welded to the metal foil 32A.

[0088] Next, an etching mask 37 patterned to the shape required for the metal wiring portion 32 is formed on the surface of the metal foil 32A (Figure 9(c)). This etching mask 37 is provided so that the portion of the metal foil 32A corresponding to the wiring pattern that 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, it may be formed by exposing a photoresist or dry film to light through a photomask and then developing it, or the etching mask may be formed on the surface of the metal foil 32A using printing technology such as an inkjet printer.

[0089] Next, the metal foil 32A located in areas not covered by the etching mask 37 is removed by immersion (Figure 9(d)). This removes the parts of the metal foil 32A other than those that will become the metal wiring section 32.

[0090] Subsequently, the etching mask 37 is removed using an alkaline stripping solution. This removes the etching mask 37 from the surface of the metal wiring section 32 (Figure 9(e)).

[0091] Next, a light-reflective insulating protective film 34 is laminated onto the metal wiring portion 32 (Figure 9(f)). The formation of the light-reflective insulating protective film 34 is not particularly limited as long as a coating means is capable of uniformly coating the material resin composition constituting the light-reflective insulating protective film 34, and methods such as screen printing, offset printing, dip coating, and brush coating can be used. Alternatively, the light-reflective insulating protective film 34 may be formed by coating the entire surface with a photosensitive insulating protective film material, exposing only the necessary areas to light through a photomask, and then developing the material.

[0092] Next, the LED chip 21, regulator 45, and connectors 44A and 44B are mounted on the metal wiring section 32 (Figure 9(g)). Note that in Figure 9(g) and Figure 9(h), which will be described later, the regulator 45 and other components are omitted from the illustration for clarity. In this case, the LED chip 21 is joined to the metal wiring section 32 by soldering via the solder section 36. This soldering can be done by reflow soldering, laser soldering, or by bonding with conductive resin.

[0093] Next, a transparent protective film 35 is formed to cover the light-reflective insulating protective film 34, the LED chip 21, the regulator 45, and the connectors 44A and 44B (Figure 9(h)). This transparent protective film 35 is preferably formed by a method of spraying a transparent resin composition (hereinafter referred to as the "spray coating method") or by a curtain coating method. The transparent protective film 35 can be formed by the spray coating method, for example, by spraying a coating liquid for spray coating containing an acrylic polyurethane resin onto a desired area on the flexible wiring board 30 using a spray coating machine to form a coating film. The transparent protective film 35 can be formed by the curtain coating method, for example, by dropping a coating liquid for curtain coating containing an acrylic polyurethane resin onto a desired area on the flexible wiring board 30 using a curtain coating machine to form a coating film.

[0094] Furthermore, the LED sheet 20 according to this embodiment is not limited to the method described above, but can also be manufactured using conventionally known flexible wiring boards for LED chips, or known methods for manufacturing various LED sheets on which LED chips are mounted.

[0095] (culture factory) Figure 10 is a schematic diagram showing the configuration of a culture factory 90 using the culture system 1 according to this embodiment. The culture factory 90 comprises a building 91 and a plurality of culture shelves 80 arranged inside the building 91.

[0096] As shown in Figure 11, the culture shelf 80 has a plurality (four) of support columns 82 and a pair of substrates 81 arranged vertically at intervals along the support columns 82. A plurality of culture systems 1 are arranged between the pairs of substrates 81. In the illustrated example, the culture systems 1 are arranged so that the longitudinal direction of the culture tubes 10 is parallel to the vertical direction. Although not shown in the illustration, the culture systems 1 may also be arranged so that the longitudinal direction of the culture tubes 10 is parallel to the horizontal direction.

[0097] Here, the control unit 40 is positioned at a sufficient distance from the culture tubes 10. Therefore, there is less risk of variations in algal growth due to heat from the control unit 40 between culture tubes 10 located close to the control unit 40 and those located far away.

[0098] The LED sheet 20 according to this embodiment is thinner compared to conventional straight-tube lighting devices. This allows for a narrower spacing between culture systems 1, and increases the number of culture systems 1 placed between pairs of substrates 81. As a result, the amount of algae grown per unit area can be increased.

[0099] As described above, according to this embodiment, the culture system 1 comprises a culture tube 10 for cultivating algae and an LED lighting device 20A that covers the outer surface of the culture tube 10. This prevents light irradiated from the LED sheet 20 onto the culture tube 10 from leaking to the outside of the culture tube 10. Therefore, the efficiency of light utilization can be increased. In addition, 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 body 11. Therefore, the efficiency of algae growth can be increased.

[0100] Furthermore, according to this embodiment, the LED sheet 20 has a flexible substrate film 31, a metal wiring section 32 on the substrate film 31, and a plurality of LED chips 21 mounted on the metal wiring section 32. In this way, because the LED sheet 20 is a sheet-shaped LED lighting device having a flexible substrate film 31, the weight of the culture system 1 can be reduced. In addition, the LED sheet 20 of the culture system 1 according to this embodiment can be made thinner overall than a straight-tube type LED bar light in which a plurality of LEDs are arranged. Therefore, when the LED sheet 20 is wrapped around the culture tube 10, the bulkiness of the culture system 1 can be suppressed. This reduces the installation space required for the culture system 1. Furthermore, because the LED sheet 20 is a sheet-shaped LED lighting device having a flexible substrate film 31, the LED sheet 20 can be easily attached to culture tubes 10 of various shapes.

[0101] Furthermore, according to this embodiment, the surface 31a of the substrate film 31 faces the culture tube 10 and is colored white. This effectively reflects light leaking out from the culture tube 10, further improving the efficiency of light utilization.

[0102] 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. This makes it easy to check the ON and OFF states of the LED chip 21 even when the LED sheet 20 is wrapped around the culture tube 10.

[0103] Furthermore, according to this embodiment, the LED sheet 20 is attached to the culture tube 10 by an adhesive member 50. This prevents an air layer from being interposed between the LED sheet 20 and the culture tube 10. As a result, reflection of light from the LED chip 21 on the outer surface of the culture tube 10 can be suppressed. This further improves the efficiency of light utilization.

[0104] Furthermore, according to this embodiment, the surface 51 of the adhesive member 50 faces the culture tube 10, and a mesh-like recess 52 is formed on the surface 51 of the adhesive member 50. This allows air interposed between the adhesive member 50 and the culture tube 10 to be released through the recess 52 when attaching the adhesive member 50 to the culture tube 10. As a result, the reflection of light from the LED chip 21 on the outer surface of the culture tube 10 can be suppressed even more effectively.

[0105] [Differentiation] Next, a modified example of the culture system 1 according to this embodiment will be described with reference to Figures 12 to 15. In Figures 12 to 15, the same reference numerals are used for parts that are the same as those in Figures 1 to 11, and detailed descriptions are omitted.

[0106] (First variation) In Figures 12 and 13, the body 11 of the culture tube 10 has a rectangular cylindrical shape. That is, the body 11 includes a pair of first side portions 11a and a pair of second side portions 11b provided between the pair of first side portions 11a. The outer surface area of ​​the first side portions 11a is larger than the outer surface area of ​​the second side portions 11b. The LED sheet 20 covers the entire body 11 of the culture tube 10 in the circumferential direction. The LED sheet 20 also covers the entire body 11 of the culture tube 10 in the longitudinal direction.

[0107] In this modified example, the molar extinction coefficient of the culture medium CS in the culture tube 10 is ε(L·cm). -1 ·g -1 Let ) be the molar concentration of the culture medium CS be C(g·L). -1 ) and when the inner width d2 of the culture tube 10 is D (cm), The photosynthetic photon flux density I0 of LED sheet 20 is 250 / 10 (-εCD / 2) ≤I0 ≤ 250 / 10 (-εCD) It is preferable to satisfy the following relationship. 250 / 10 (-εCD / 2)By satisfying the relationship ≤ I0, the efficiency of algae growth can be improved. Also, I0 ≤ 250 / 10 (-εCD) By satisfying this relationship, power consumption can be reduced. In this specification, the inner width d2 of the culture tube 10 means the distance between the inner surfaces of the pair of first side portions 11a.

[0108] In this modified example, the light irradiated from the LED sheet 20 onto the culture tube 10 can be prevented from leaking outside the culture tube 10. This improves the efficiency of light utilization. Furthermore, light can be irradiated into the culture tube 10 from the entire circumference of the body 11, improving the efficiency of algae growth.

[0109] (Second variation) In Figure 14, the LED sheet 20 covers only the outer surface of the first side portion 11a of the body portion 11. That is, the LED sheet 20 does not cover the outer surface of the second side portion 11b of the body portion 11. In this modified example as well, it is possible to suppress the leakage of light irradiated from the LED sheet 20 onto the culture tube 10 to the outside of the culture tube 10. Therefore, the efficiency of light utilization can be increased.

[0110] (Third variation) In Figure 15, the LED lighting device 20A includes an LED bar light 16 containing multiple LED chips 21 and a reflective sheet 15 attached to the LED bar light 16. The LED bar light 16 is a straight tube type with multiple LEDs 21 arranged in a row, and the LED bar light 16 is installed between the culture tube 10 and the reflective sheet 15.

[0111] The reflective sheet 15 plays the role of reflecting the light emitted from the LEDs of the LED bar light 16. Preferably, the reflective sheet 15 covers the entire area of ​​the culture tube 10 in the longitudinal direction of the culture tube 10. The reflective sheet 15 is attached to the culture tube 10 by an adhesive member 50. Such a reflective sheet 15 may be composed of, for example, a metal plate, a sheet made by laminating a resin film onto a metal plate, a resin sheet, or a nonwoven fabric. Here, the resin sheet has good diffuse reflectivity. For this reason, the reflective sheet 15 is preferably a sheet that includes at least a resin sheet, and more preferably a sheet that includes at least a porous resin sheet. The reflective sheet 15 may also be composed only of a porous resin sheet, or it may further include other sheets in addition to the porous resin sheet. Examples of other sheets include a reinforcing sheet. The porous resin sheet and the reinforcing sheet may be laminated together via an adhesive layer, or they may be laminated together without an adhesive layer. In addition, other multilayer films with titanium dioxide added may be used as the reflective sheet 15. The resin used in the resin sheet may be a thermoplastic resin or a thermosetting resin, but a thermoplastic resin is preferred. Examples of thermoplastic resins include polyolefin resins, acrylic resins, styrene resins, vinyl fluoride resins, amide resins, or saturated ester resins. Of these, polyolefin resins have excellent heat resistance, water resistance, chemical resistance, and cost. For this reason, polyolefin resins are preferred as thermoplastic resins for resin sheets.

[0112] According to this modified example, it is possible to suppress the leakage of light irradiated from the LED bar light 16 onto the culture tube 10 to the outside of the culture tube 10. Therefore, the efficiency of light utilization can be increased.

[0113] The multiple components disclosed in the above embodiments and each of the variations can be combined as needed. Alternatively, some components may be removed from all the components shown in the above embodiments and each of the variations. [Explanation of symbols]

[0114] 1. Culture System 10 culture tubes 15 Reflective sheet 16 LED bar lights 20 LED sheets 20A LED lighting device 21 LED chips 22 Metal wiring section 25 Display section 31 Substrate film 31a surface 32 Metal wiring section 50 Adhesive material 51 Surface 52 recess CS culture solution

Claims

1. Culture tubes for culturing algae, The system includes an LED lighting device that covers the outer surface of the culture tube, The aforementioned LED lighting device is an LED sheet, A culture system in which the LED sheet is attached to the culture tube by an adhesive member.

2. The culture system according to claim 1, wherein the LED sheet comprises a flexible substrate film, a metal wiring portion on the substrate film, and a plurality of LED chips mounted on the metal wiring portion.

3. The culture system according to claim 2, wherein the surface of the substrate film faces the culture tube and is colored white.

4. The culture system according to claim 2 or 3, wherein the LED sheet is provided with a display unit that displays the ON state of the LED chip and the OFF state of the LED chip.

5. The culture system according to any one of claims 1 to 4, wherein the peel strength between the LED sheet and the culture tube is 3 N / 15 mm or more and 30 N / 15 mm or less.

6. Culture tubes for culturing algae, The system includes an LED lighting device that covers the outer surface of the culture tube, The LED lighting device comprises an LED bar light containing a plurality of LED chips and a reflective sheet attached to the LED bar light. The LED bar light is provided between the culture tube and the reflective sheet. A culture system in which the reflective sheet is attached to the culture tube by an adhesive member.

7. The culture system according to any one of claims 1 to 6, wherein the refractive index of the adhesive member is 1.48 or more and 1.60 or less.

8. The culture system according to any one of claims 1 to 7, wherein the surface of the adhesive member faces the culture tube, and a mesh-like recess is formed on the surface of the adhesive member.

9. The culture system according to any one of claims 1 to 8, wherein the adhesive member comprises ethylene vinyl acetate or polyvinyl butyral.

10. The molar extinction coefficient of the culture medium in the culture tube is ε(L·cm) －１ ・g －１ ) and the molar concentration of the culture medium is set to C (g·L). －１ ) and when the inner diameter or inner width of the culture tube is D (cm), The photosynthetic photon flux density I of the LED lighting device ０ teeth, 250 / 10 （－εＣＤ／２） ≦I ０ ≦250 / 10 （－εＣＤ） A culture system according to any one of claims 1 to 9 that satisfies the following relationship.

11. The culture tube has a hollow body, The culture system according to any one of claims 1 to 10, wherein the body portion has a rectangular cylindrical shape.

Images