LED lighting sheet for growing plants and animals, LED lighting module for growing plants and animals, shelf board for growing shelves for growing plants and animals, growing shelves for growing plants and animals, and plant and animal growing factories

Abstract

To provide an LED lighting sheet for growing animals and plants which enables increase of the light volume from the LED lighting sheet for growing animals and plants to obtain animals or plates with a high yield, and to provide an LED lighting module for growing animals and plants, a shelf board for a growing shelf for animals and plants, a growing shelf for animals and plants, and a factory for growing animals and plants.SOLUTION: An LED lighting sheet 20 for growing animals and plants includes: a substrate film 31; a metal wiring part 32 formed on a surface of the substrate film 31; and an LED chip 21 mounted on the metal wiring part 32 and having a light emitting part 21d; and a protection part 35A which covers at least a part of the light emitting part 21d of the LED chip 21 and protects the LED chip 21. A refraction index of the protection part 35A is set between a refraction index of air and a refraction index of the light emitting part 21d of the LED chip 21.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to an LED lighting sheet for growing animals and plants, an LED lighting module for growing animals and plants, a shelf board for a shelf for growing animals and plants, a shelf for growing animals and plants, and an animal and plant growing factory. [Background technology]

[0002] In recent years, there has been growing demand for lighting devices that use low-power LEDs as light sources, replacing conventional fluorescent lamps and high-pressure sodium lamps, as lighting devices used in animal and plant cultivation factories.

[0003] One example of an animal and plant cultivation factory that uses lighting devices with LEDs as light sources is a plant cultivation device in which multiple straight-tube plant cultivation lights with LEDs as light sources are arranged on the shelves of a plant cultivation shelf (see, for example, Patent Document 1).

[0004] An LED lighting device for growing animals and plants has also been proposed, in which a planar light source is formed by arranging multiple LED chips on a flexible circuit board (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-118957 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-251230 Summary of the Invention [Problem to be solved by the invention]

[0006] The present disclosure provides an LED lighting sheet for cultivating animals and plants, an LED lighting module for cultivating animals and plants, a shelf for cultivating shelves for cultivating animals and plants, an animal and plant cultivating shelf, and an animal and plant cultivating factory, which increase the amount of light from the LED lighting sheet for cultivating animals and plants and enable good yields of animals and plants to be obtained. [Means for solving the problem]

[0007] The LED lighting sheet for cultivating animals and plants according to this embodiment is an LED lighting sheet for cultivating animals and plants, and comprises a substrate film, a metal wiring section formed on the surface of the substrate film, an LED chip mounted on the metal wiring section, and a protective section that covers at least a portion of the light-emitting section of the LED chip and protects the LED chip, and the refractive index of the protective section is between the refractive index of air and the refractive index of the light-emitting section of the LED chip.

[0008] In the LED illumination sheet for growing animals and plants according to this embodiment, the refractive index of the protective portion may be 1.39 or more and 1.60 or less.

[0009] In the LED illumination sheet for growing animals and plants according to this embodiment, the contact angle of the protective portion with respect to water may be greater than 20°.

[0010] In the LED illumination sheet for growing animals and plants according to this embodiment, the protective portion may have a contact angle with water of 50° or more.

[0011] In the LED illumination sheet for growing animals and plants according to this embodiment, the protective portion may have a contact angle with water of 80° or more.

[0012] In the LED illumination sheet for growing animals and plants according to this embodiment, the LED chip is mounted on the metal wiring part via a solder part, and the solder part extends from the back surface to the side surface of the LED chip, and the protective part may cover the solder part located on the side of the LED chip.

[0013] In the LED illumination sheet for cultivating plants and animals according to this embodiment, the protective portion may include a central portion covering at least a portion of the surface of the LED chip, a curved portion covering at least a portion of the side surface of the LED chip, and a flat portion formed adjacent to the curved portion.

[0014] The LED illumination sheet for cultivating plants and animals according to this embodiment may further include a light-reflective insulating protective film arranged to cover the metal wiring portion, and the protective portion may cover the light-reflective insulating protective film.

[0015] In the LED lighting sheet for cultivating animals and plants according to this embodiment, in a cross section perpendicular to the light-emitting surface of the LED lighting sheet for cultivating animals and plants, the curved portion may have a concave shape that is recessed from the light-emitting surface side of the LED lighting sheet for cultivating animals and plants toward the surface opposite the light-emitting surface.

[0016] In the LED lighting sheet for growing animals and plants according to this embodiment, in a cross section perpendicular to the light-emitting surface of the LED lighting sheet for growing animals and plants, the thickest part of the solder portion does not have to be in contact with the side of the LED chip.

[0017] In the LED lighting sheet for cultivating animals and plants according to this embodiment, when viewed from the light-emitting surface side of the LED lighting sheet for cultivating animals and plants, the portion of the solder part located on the side of the LED chip may be formed so as to surround part of the side surface of the LED chip.

[0018] The LED lighting module for cultivating animals and plants according to this embodiment is an LED lighting module for cultivating animals and plants, and comprises an LED lighting sheet for cultivating animals and plants according to this embodiment, and a control unit electrically connected to the LED lighting sheet for cultivating animals and plants, and the control unit is externally connected to the LED lighting sheet for cultivating animals and plants.

[0019] In the LED lighting module for growing animals and plants according to this embodiment, a constant voltage may be applied from the control unit to the LED lighting sheet for growing animals and plants.

[0020] In the LED lighting module for growing animals and plants according to this embodiment, the control unit may be capable of controlling dimming of the LED chips.

[0021] The shelf board for a shelf for growing animals and plants according to this embodiment is a shelf board for a shelf for growing animals and plants, and comprises a base plate and an LED lighting sheet for growing animals and plants according to this embodiment or an LED lighting module for growing animals and plants according to this embodiment attached to the base plate.

[0022] In the plant and animal growing shelf according to this embodiment, the LED illumination sheet for growing plants and animals may be further arranged on the side surface of the shelf board.

[0023] The animal and plant cultivation shelf according to this embodiment is a shelf for cultivating animals and plants, and comprises a shelf board, and the shelf board comprises an LED lighting sheet for cultivating animals and plants according to this embodiment or an LED lighting module for cultivating animals and plants according to this embodiment attached to the underside of a substrate.

[0024] The animal and plant growing factory according to this embodiment includes a building and a plant and animal growing shelf according to this embodiment arranged inside the building. [Effects of the Invention]

[0025] According to this embodiment, the amount of light from the LED illumination sheet for growing plants and animals can be increased, and plants and animals can be grown in good yields. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 1 is a schematic diagram illustrating an LED lighting module according to one embodiment. [Figure 2] FIG. 2 is a plan view showing an LED illumination sheet according to one embodiment. [Figure 3] 3(a) and 3(b) are plan views showing modified examples of the LED illumination sheet. [Figure 4] Figure 4(a) is a graph showing the relationship between time and voltage when a constant voltage is applied to the LED lighting sheet from the control unit, and Figure 4(b) is a graph showing the relationship between time and voltage when a pulse is applied to the LED lighting sheet as a comparative example. [Figure 5]FIG. 5 is a cross-sectional view (cross-sectional view taken along line VA-VA in FIG. 2) showing an LED illumination sheet according to one embodiment. [Figure 6] FIG. 6 is an enlarged view showing a protective portion of the LED illumination sheet according to one embodiment (an enlarged view corresponding to portion VI in FIG. 5). [Figure 7] FIG. 7 is a plan view (view taken in the direction of arrow VII in FIG. 5) showing LED chips of an LED illumination sheet according to one embodiment. [Figure 8] FIG. 8 is a schematic diagram showing the refraction of light emitted from an LED chip. [Figure 9] FIG. 9 is a graph showing the change in the reflectance (vertical axis) of light throughout the entire range from the LED chip to the air when the refractive index (horizontal axis) of the transparent protective film is changed. [Figure 10] FIG. 10 is a graph showing the directional characteristics of an LED chip. [Figure 11] FIG. 11 is a diagram showing the illumination range of light from the LED chip. [Figure 12] 12(a)-(i) are cross-sectional views showing a manufacturing method of an LED illumination sheet according to one embodiment. [Figure 13] FIG. 13 is a schematic perspective view showing a plant cultivation factory according to one embodiment. [Figure 14] FIG. 14 is a schematic perspective view of a plant growing shelf according to one embodiment. [Figure 15] 15(a)-(b) are diagrams showing modified examples of plant growing shelves. DETAILED DESCRIPTION OF THE INVENTION

[0027] The LED lighting sheet for growing animals and plants according to this embodiment comprises a substrate film, a metal wiring portion formed on the surface of the substrate film, an LED chip having a light-emitting portion mounted on the metal wiring portion, and a protective portion that covers at least a portion of the light-emitting portion of the LED chip to protect the LED chip. The refractive index of the protective portion is between the refractive index of air and the refractive index of the light-emitting portion of the LED chip.

[0028] Because the LED lighting sheet for growing animals and plants according to this embodiment is a sheet-shaped LED lighting device, its overall thickness can be thinner than that of an LED bar light with an array of multiple straight-tube LEDs. This allows for narrower vertical spacing between shelves in the animal and plant growing racks, improving yield per unit floor area of ​​the plant and animal growing factory. Furthermore, the thickness of the LED chips is smaller than that of straight-tube LEDs. Therefore, the height difference between areas where LED chips are located and areas where LED chips are not located can be smaller than the height difference between areas where straight-tube LEDs are located and areas where straight-tube LEDs are not located. This reduces the occurrence of shadows on the sides of the LED chips. This reduces the variation in light irradiated to animals and plants, even when the animals and plants grow close to the LED lighting sheet. In an LED lighting device for growing animals and plants, reducing the variation in light irradiated to animals and plants is important because it ensures that the size and quality of the plants being grown meet certain specifications and reduces non-conforming products. In the cultivation of plants and animals, it is important to control the light and heat irradiated to the plants and animals during the later stages of growth when photosynthesis becomes more active. The LED lighting sheet for cultivating plants and animals according to this embodiment can suppress variations in the relatively strong light irradiated to plants and animals when they are placed close to the LED lighting sheet.

[0029] Furthermore, in the LED illumination sheet for cultivating animals and plants according to this embodiment, the protective portion covers at least a portion of the light-emitting portion of the LED chip, protecting the LED chip. This prevents the LED chip from peeling off from the LED illumination sheet even if a worker or other person in the animal or plant cultivating factory touches the LED chip. This prevents the LED chip from falling onto the animals or plants being cultivated, and prevents the light-emitting portion of the LED chip from coming into contact with the animals or plants. This allows the hygienic condition of the cultivated animals and plants to be maintained in good condition.

[0030] Furthermore, in the LED illumination sheet for cultivating animals and plants according to this embodiment, the refractive index of the protective portion is between the refractive index of air and the refractive index of the light-emitting portion of the LED chip. Generally, the light source used in animal and plant cultivation factories lacks sufficient light output, and there is a demand for even greater light output. By setting the refractive index of the protective portion between the refractive index of air and the refractive index of the light-emitting portion of the LED chip, the following relationship is established: refractive index of the light-emitting portion of the LED chip > refractive index of the protective portion > refractive index of the air. This allows the refractive index of light to gradually change from the light-emitting portion of the LED chip to the air. This reduces the overall light reflectance from the light-emitting portion of the LED chip to the air, improving the transmittance of light from the LED chip and increasing the light output. In this way, increasing the light output from the LED illumination sheet improves the cultivation efficiency of animals and plants. As a result, the amount of cultivated animals and plants can be increased while suppressing a decrease in yield, resulting in a good yield of animals and plants.

[0031] In addition, the LED lighting module for growing animals and plants according to this embodiment comprises an LED lighting sheet for growing animals and plants and a control unit electrically connected to the LED lighting sheet, and the control unit is externally connected to the LED lighting sheet.

[0032] The LED lighting module for cultivating plants and animals according to this embodiment has an external control unit, which allows for increased growth of the plants and animals while minimizing a decrease in yield, resulting in a good yield of plants and animals. Heat generated locally near the control unit has a strong effect on plants and animals grown close to the control unit and little effect on plants and animals grown far from the control unit. This can lead to variations in the state of growth of plants and animals, resulting in an increase in non-conforming products and a decrease in yield. The greater the light output of the LED lighting sheet, the greater the heat generated by the control unit. With an LED lighting module with an external control unit connected to the LED lighting sheet, the control unit can be installed anywhere, minimizing variation and achieving a good yield.

[0033] The shelf boards for animal and plant cultivation shelves, the animal and plant cultivation shelves, and the animal and plant cultivation factory according to this embodiment are equipped with the LED lighting sheets or modules for animal and plant cultivation according to the above-mentioned embodiment, so that good yields of animals and plants can be obtained.

[0034] An embodiment of the present invention will be described in detail below with reference to the drawings. The figures shown below are schematic illustrations. Therefore, the size and shape of each part are appropriately exaggerated for ease of understanding. Furthermore, appropriate modifications can be made without departing from the spirit and scope of the present invention. In the figures shown below, identical parts are designated by the same reference numerals, and some detailed descriptions may be omitted. Furthermore, the numerical values, such as dimensions, and material names of each component described in this specification are merely examples of an embodiment and are not limited to these. They may be selected and used as appropriate. In this specification, terms specifying shapes or geometric conditions, such as parallel, orthogonal, and perpendicular, are intended to include not only their strict meanings but also substantially the same states. In this specification, the term "animals and plants" refers to animals and / or plants. For convenience, the following description will be given using an LED lighting module to grow (cultivate) plants. However, the present specification can also be applied to growing animals within the scope of consistent understanding.

[0035] (LED lighting module for plant growth) An LED lighting module 10 for plant cultivation (hereinafter also referred to as LED lighting module 10) according to this embodiment shown in Fig. 1 is installed in a plant cultivation factory 90 (Fig. 13) that uses artificial light, as will be described later, to cultivate plants. Such an LED lighting module 10 includes an LED lighting sheet 20 for plant cultivation (hereinafter also referred to as LED lighting sheet 20) and a control unit 40 electrically connected to the LED lighting sheet 20.

[0036] As shown in FIG. 2, the LED lighting sheet 20 has multiple LED chips 21 arranged on the light-emitting surface 20a side of the sheet (the side facing the plants during use). By using such a direct-type LED lighting sheet 20, the light emitted from the LED chips 21 passes directly through the light-emitting surface 20a and reaches the plants directly below, thereby increasing the amount of light and promoting plant growth. Furthermore, the overall thickness of the sheet can be reduced, making it less likely for shadows to form on the sides of the LED chips 21. The LED lighting sheet 20 in FIG. 2 includes a flexible wiring substrate 30 and multiple LED chips 21 regularly arranged on the flexible wiring substrate 30. Using such a flexible wiring substrate 30 allows for the creation of an LED lighting sheet 20 with a relatively large sheet surface area. Generally, multiple LED lighting sheets 20 are arranged in a plant cultivation factory or on plant cultivation shelves. However, if the positions of adjacent LED lighting sheets 20 are not aligned evenly, variations in the amount of light can occur, potentially resulting in reduced plant yield. The LED lighting sheet 20, which has a relatively large sheet surface area, can reduce the number of LED lighting sheets 20 used, thereby suppressing variations in the amount of light due to the arrangement of multiple LED lighting sheets 20. Note that while FIG. 2 shows an example of an LED lighting sheet 20 equipped with a flexible wiring substrate 30, this is not limiting and an LED lighting sheet equipped with a rigid wiring substrate may also be used. LED lighting sheets equipped with a rigid wiring substrate have high resistance to stress and are less likely to break. Note that FIG. 2 does not show the light-reflective insulating protective film 34 and transparent protective film 35, which will be described later.

[0037] In this case, the LED chips 21 are arranged in a lattice pattern in a plan view within the flexible wiring substrate 30. That is, the LED chips 21 are arranged in multiple rows and columns in a matrix, and N rows R of M LED chips 21 are arranged, each row being a series of LED chips 21. For example, in FIG. 2, 14 LED chips 21 (M=14) are connected in series along the first arrangement direction (X direction) of the LED chips 21. Furthermore, these rows R, each having 14 LED chips 21, are arranged in parallel in 10 rows (N=10) along the second arrangement direction (Y direction) of the LED chips 21. Note that the number of LED chips 21 arranged is not limited to this. Specifically, it is preferable to arrange 10 to 14 LED chips 21 in series in the first arrangement direction (X direction) (14≧M≧10), and to arrange these rows R in parallel in 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 LED chips 21 can be arranged at short intervals along the first arrangement direction (X direction), reducing in-plane variations in the illuminance of the LED illumination sheet 20 and the variation in the light irradiated onto plants. By arranging 14 or fewer LED chips 21 in series, power consumption can be reduced, thereby lowering running costs such as utility bills in the plant cultivation factory 90. Furthermore, by arranging the LED chips 21 in four or more parallel rows in the second arrangement direction (Y direction) of the LED chips 21, even if a specific LED chip 21 is damaged, the damage does not spread to the LED chips 21 in other rows, preventing a drastic decrease in the illuminance of the entire LED illumination sheet 20. Furthermore, by limiting the area where the illuminance of the LED illumination sheet 20 is reduced, the area where non-conforming products may be produced can be limited, thereby preventing a decrease in yield. Furthermore, when the LED illumination sheet 20 is a direct-illumination type, there is a high risk of the LED chips 21 being damaged by accidentally touching them too hard during installation or cleaning. Therefore, it is important from a risk management perspective to take measures against damage. Furthermore, by arranging the LED chips 21 in parallel in 10 or fewer rows, it is possible to reduce power consumption and running costs such as utility costs in the plant cultivation factory 90.

[0038] The LED lighting sheet 20 has a plurality of metal wiring portions 22, which are arranged in a first arrangement direction (X direction). The plurality of metal wiring portions 22 arranged in the first arrangement direction (X direction) correspond to respective rows 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. Furthermore, each terminal (not shown) of the LED chip 21 is electrically connected to each pair of metal wiring portions 22. The plurality of metal wiring portions 22 constitute a power supply portion for the LED chips 21, and when power is supplied to the plurality of metal wiring portions 22, all of the LED chips 21 arranged in the corresponding row R are illuminated. The plurality of metal wiring portions 22 constitute a part of a metal wiring portion 32, which will be described later.

[0039] The interval Px between the LED chips 21 in the first arrangement direction (X direction) is preferably 37 mm or more and 50 mm or less. The interval Py between the LED chips 21 in the second arrangement direction (Y direction) is preferably 37 mm or more and 100 mm or less. By setting the intervals between the LED chips 21 within the above range, the brightness of the LED illumination sheet 20 can be made uniform across the surface, reducing variations in the light irradiated onto plants and reducing the power consumption of the LED illumination sheet 20.

[0040] The thickness of the thickest part of the LED illumination sheet 20 is preferably 5 mm or less. By reducing the thickness of the LED illumination sheet 20 in this way, the vertical spacing between the substrates 81 (FIG. 14) on which the LED illumination sheets 20 are installed can be narrowed, thereby increasing the number of substrates 81 per plant cultivation shelf 80 (FIG. 14). As a result, the plant yield per unit area can be increased. In addition, the variation in the relatively strong light irradiated on the plants when the plants and the LED illumination sheet 20 are close to each other can be further reduced.

[0041] The arrangement of the LED chips 21 is not limited to a lattice-like arrangement in a plan view, but may be a staggered arrangement in a plan view as shown in FIG. 3( a). The LED chips 21 do not need to be uniformly arranged across the surface of the LED illumination sheet 20. For example, the density of the LED chips 21 may be increased at the periphery of the LED illumination sheet 20. Specifically, as shown in FIG. 3( b), the LED chips 21 may be arranged in a lattice-like arrangement in the center of the LED illumination sheet 20 (the lower part of FIG. 3( b)) and in a staggered arrangement at the periphery of the LED illumination sheet 20 (the upper part of FIG. 3( b)). This arrangement prevents a decrease in brightness of the LED illumination sheet 20 at the periphery of the LED illumination sheet 20, uniforms the brightness of the LED illumination sheet 20 across the surface, and reduces variations in the light irradiated to plants.

[0042] The overall shape of the LED lighting sheet 20 is rectangular in a plan view, but there are no particular limitations on the size or planar shape of the LED lighting sheet 20. The LED lighting sheet 20 has a high degree of freedom in processing the size and shape, so it can flexibly meet various demands in this regard. Furthermore, by taking advantage of its flexibility, it can be attached to installation surfaces of various shapes, not just flat installation surfaces.

[0043] In FIG. 2, the length Lx of the LED illumination sheet 20 in the first arrangement direction (X direction) is preferably 500 mm to 700 mm, more preferably 550 mm to 650 mm. The length Ly of the LED illumination sheet 20 in the second arrangement direction (Y direction) is preferably 300 mm to 500 mm, more preferably 350 mm to 450 mm. By keeping the size of the LED illumination sheet 20 within the above range, the LED illumination sheet 20 can be fitted to a general plant cultivation substrate 81 ( FIG. 14 ), reducing dead space on the substrate 81. Furthermore, by not allowing the size of each LED illumination sheet 20 to be excessively large, damage to other LED chips 21 can be minimized. This prevents a significant decrease in the illuminance of the entire plant cultivation shelf 83 ( FIG. 14 ) and limits the extent of the illuminance decrease.

[0044] Next, the control unit 40 will be described. As shown in FIG. 1, the control unit 40 supplies power to the LED illumination sheet 20 and controls the light emission and other aspects of the LED illumination sheet 20. The control unit 40 is detachably connected to the LED illumination sheet 20 via a first connector 44A provided on the LED illumination sheet 20. In other words, the control unit 40 is configured separately from the LED illumination sheet 20 and is externally connected to the LED illumination sheet 20. In other words, the control unit 40 is not integrated with the LED illumination sheet 20. This allows the control unit 40, which serves as a heat source, to be separated from the LED illumination sheet 20, preventing the heat from the control unit 40 from affecting plant growth.

[0045] The control unit 40 also has a power input unit 41, an AC / DC converter (driver) 42, and a PWM control unit 43. An AC voltage of any voltage, for example, between 100V and 240V, is supplied to the power input unit 41. The AC / DC converter 42 converts the AC voltage of 100V to 240V into a constant DC voltage (for example, 44V). The PWM control unit 43 adjusts the pulse width of the constant voltage waveform from the AC / DC converter 42 to adjust the brightness of the LED chips 21 of the LED illumination sheet 20. In other words, the PWM control unit 43 also functions as a dimming control unit that controls the brightness of the LED illumination sheet 20. The constant voltage output from the PWM control unit 43 is applied to the LED illumination sheet 20 via the first connector 44A.

[0046] Applying a constant voltage from the PWM control unit 43 of the control unit 40 to the LED illumination sheet 20 makes it possible to adjust the brightness of the LED chips 21, unlike when a rectified pulse voltage is applied directly to the LED illumination sheet 20. That is, the PWM control unit 43 can arbitrarily control the illuminance of the LED chips 21 by appropriately changing the duty ratio of the DC voltage from the AC / DC converter 42. For example, as shown in FIG. 4(a), the PWM control unit 43 can reduce the illuminance of the LED chips 21 by reducing the duty ratio of the constant voltage from the AC / DC converter 42 from 100% (solid line) to 50% (dotted line).

[0047] By appropriately adjusting the illuminance of the LED chips 21 in this way, the illuminance of the LED illumination sheet 20 can be adjusted according to the growth stage of the plant, thereby adjusting the degree of plant growth. For example, the illuminance of the LED illumination sheet 20 may be lowered in the early growth stage when the plant's leaves are small, and increased in the later growth stage when the plant's leaves are large. Alternatively, the illuminance of the LED illumination sheet 20 may be increased in the early growth stage when the plant is short and the distance between the plant and the LED chips 21 is large, and decreased in the later growth stage when the plant is tall and the distance between the plant and the LED chips 21 is small. As another example of adjusting the illuminance of the LED illumination sheet 20, the illuminance may be increased for plants that require high illuminance and decreased for plants that can grow even in low illuminance. The illuminance may be increased when earlier shipping is desired, and decreased when later shipping is desired.

[0048] Furthermore, by applying a constant voltage to the LED illumination sheet 20 from the PWM control unit 43, the integrated light amount per unit time from the LED illumination sheet 20 can be increased. That is, for example, the integrated light amount when a constant voltage is applied to the LED illumination sheet 20 (the area of ​​the shaded portion in FIG. 4(a)) can be made larger than the integrated light amount when a voltage is applied in pulses as a comparative example (the area of ​​the shaded portion in FIG. 4(b)). This increases the luminous efficiency of the light from the LED illumination sheet 20 and improves plant growth efficiency.

[0049] Referring back to FIG. 1 , the LED illumination sheet 20 is provided with regulators 45. In this case, a regulator 45 is provided for each row of LED chips 21. Specifically, ten regulators 45 are provided corresponding to the ten rows of LED chips 21. These regulators 45 serve to maintain a constant current flowing through the LED chips 21 in each row. This prevents excessive current from flowing through the LED chips 21 in other rows, even if one LED chip 21 is damaged, thereby preventing damage to the LED chips 21 in the other rows. As a result, the illuminance of the entire LED illumination sheet 20 is prevented from decreasing drastically, and variations in the light irradiated to plants are reduced. Furthermore, the regulators 45 can control the amount of current controlled for each row by connecting resistors. For example, by changing the control resistor values ​​for the first and last rows, it is possible to increase the output of only the peripheral rows. Normally, the aim is to ensure uniformity by laying the LED lighting sheets 20 close together without any gaps, but even if the LED lighting sheets 20 are spaced 5 to 10 cm apart from each other from the standpoint of cost or ensuring breathability, the effect of eliminating the seams can be expected.

[0050] Furthermore, the LED illumination sheet 20 is provided with a power supply line 46 branching off from the first connector 44A. A second connector 44B is also provided on the LED illumination sheet 20. The power supply line 46 is not electrically connected to the LED chips 21 of the LED illumination sheet 20, but is electrically connected to the wiring of another LED illumination sheet 200 having the same configuration as the LED illumination sheet 20. That is, the power supply line 46 is detachably connected to the wiring of the LED illumination sheet 200 via the second connector 44B and another first connector 44A provided on the other LED illumination sheet 200. Current from the power supply line 46 is supplied to the other LED illumination sheet 200 via the second connector 44B and the other first connector 44A. This allows the two LED illumination sheets 20, 200 to be connected together and controlled simultaneously by a single control unit 40. By being able to control multiple LED lighting sheets 20 simultaneously with one control unit 40, the number of control units 40, which are sources of heat, can be reduced, making it less likely that variations in plant growth due to heat from the control units 40 will occur, and reducing yield declines.

[0051] (Each component of the LED lighting sheet) Next, we will explain each component that makes up the LED illumination sheet 20. As shown in Fig. 5, the LED illumination sheet 20 includes a flexible wiring board 30 and a plurality of LED chips 21 arranged on the flexible wiring board 30. The flexible wiring board 30 includes a flexible substrate film 31 and a metal wiring section 32 formed on the surface of the substrate film 31 (the surface on the light-emitting surface 20a side). The metal wiring section 32 is laminated on the substrate film 31 via an adhesive layer 33.

[0052] Each LED chip 21 is mounted in a manner that allows electrical continuity with the metal wiring portion 32. In this LED illumination sheet 20, the LED chips 21 are mounted on the flexible wiring substrate 30, so that the multiple LED chips 21 can be arranged at a desired high density.

[0053] A light-reflective insulating protective film 34 is formed on the LED lighting sheet 20, covering the entire area except for the areas where the LED chips 21, regulators 45, and connectors 44 are provided and the surrounding area. This light-reflective insulating protective film 34 is disposed so as to cover the metal wiring section 32. The light-reflective insulating protective film 34 is a layer that combines an insulating function that contributes to improving the migration resistance of the LED lighting sheet 20 and a light-reflecting function that contributes to improving the lighting environment created by the LED lighting sheet 20. This layer is formed from an insulating resin composition containing a white pigment. If the migration resistance and light-reflecting function can be obtained with only the metal wiring section 32 and the transparent protective film 35 described below, a structure without the light-reflective insulating protective film 34 is also possible.

[0054] Also provided is a protective portion 35A that covers the light-reflective insulating protective film 34 and the LED chips 21 to protect the LED chips 21. The protective portion 35A has a transparent protective film 35. This transparent protective film 35 is a resin film that is formed on the outermost surface (the surface closest to the light-emitting surface 20a) of the LED lighting sheet 20 mainly to ensure waterproofing of the LED lighting sheet 20. The transparent protective film 35 according to this embodiment may be formed by, for example, a method of spraying a transparent resin composition by spraying (hereinafter referred to as a "spray coating method") or a method of forming by a curtain coating method.

[0055] A solder portion 36 is provided on the metal wiring portion 32. Each LED chip 21 is electrically connected to the metal wiring portion 32 via the solder portion 36. Note that each LED chip 21 may be mounted on the metal wiring portion 32 via a conductive resin.

[0056] (substrate film) A flexible resin film can be used for the substrate film 31 shown in Fig. 5. In this specification, "flexible" means "capable of being bent to a radius of curvature of at least 1 m or less, preferably 50 cm, more preferably 30 cm, even more preferably 10 cm, and particularly preferably 5 cm."

[0057] The substrate film 31 may be made of a thermoplastic resin with high heat resistance and insulating properties. Examples of such resins include polyimide resin (PI) and polyethylene naphthalate (PEN), which have excellent heat resistance, dimensional stability when heated, mechanical strength, and durability. Among these, polyethylene naphthalate (PEN) whose heat resistance and dimensional stability have been improved by undergoing a heat resistance improvement treatment such as annealing treatment can be preferably used. Polyethylene terephthalate (PET) whose flame retardancy has been improved by adding a flame-retardant inorganic filler or the like can also be used.

[0058] The thickness of the substrate film 31 is not particularly limited, but is preferably from about 10 μm to 500 μm, more preferably from 50 μm to 250 μm, from the viewpoints of not becoming a bottleneck in the heat dissipation path, of having heat resistance and insulating properties, and of balancing production costs. Furthermore, the thickness is preferably within the above range from the viewpoint of maintaining good productivity when manufacturing using a roll-to-roll method.

[0059] (adhesive layer) Any known resin adhesive can be used as the adhesive for forming the adhesive layer 33. Among these resin adhesives, urethane-based, polycarbonate-based, silicone-based, acrylic-based, or epoxy-based adhesives can be particularly preferably used.

[0060] (Metal wiring part) The metal wiring portion 32 is a wiring pattern formed on the surface (the surface on the light-emitting surface 20a side) of the substrate film 31 using a conductive base material such as metal foil. The metal wiring portion 32 is preferably formed on the surface of the substrate film 31 via an adhesive layer 33 by a dry lamination method. The metal wiring portion 32 includes the above-described plurality of metal wiring portions 22. The plurality of metal wiring portions 22 include a first metal wiring portion 22A and a second metal wiring portion 22B disposed spaced apart from the first metal wiring portion 22A. The first metal wiring portion 22A and the second metal wiring portion 22B are mounted with an LED chip 21, 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 configured to light up when power is supplied to the first metal wiring portion 22A and the second metal wiring portion 22B.

[0061] The metal wiring portion 32 preferably has both high levels of heat dissipation and electrical conductivity, and copper foil, for example, can be used. In this case, heat dissipation from the LED chips 21 is stabilized and an increase in electrical resistance is prevented, thereby reducing variations in light emission between the LED chips 21 and enabling stable light emission. This also extends the life of the LED chips 21. Furthermore, deterioration of peripheral components such as the substrate film 31 due to heat can be prevented, thereby extending the product life of the LED illumination sheet 20. Examples of metals that can form the metal wiring portion 32 include copper, as mentioned above, as well as aluminum, gold, silver, etc.

[0062] The thickness of the metal wiring portion 32 may be set appropriately depending on the magnitude of the withstand current required for the flexible wiring substrate 30. However, in order to suppress warping due to thermal contraction of the substrate film 31 during soldering processing such as reflow soldering, the thickness of the metal wiring portion 32 is preferably 10 μm or more. On the other hand, the thickness of the metal wiring portion 32 is preferably 50 μm or less, which allows the flexible wiring substrate 30 to maintain sufficient flexibility and also prevents deterioration of handleability due to increased weight.

[0063] (solder part) The solder portion 36 joins the metal wiring portion 32 and the LED chip 21. This solder joining can be performed by a reflow method. As shown in FIG. 6, the solder portion 36 according to this embodiment extends from the back surface 21c to the side surface 21b of the LED chip 21. In addition, in a cross section perpendicular to the light-emitting surface 20a of the LED illumination sheet 20, the portions of the solder portion 36 located on the sides of the LED chip 21 have a curved shape that rises toward the light-emitting surface 20a. In this embodiment, the portions of the solder portion 36 located on the sides of the LED chip 21 are formed in a substantially semicircular shape in a cross section perpendicular to the light-emitting surface 20a of the LED illumination sheet 20. In this specification, the term "cross section perpendicular to the light-emitting surface of the LED illumination sheet" refers to a cross section along the direction (Z direction) perpendicular to the first arrangement direction (X direction) and the second arrangement direction (Y direction).

[0064] 5 and 6, in a cross section perpendicular to the light-emitting surface 20a of the LED illumination sheet 20, the thickest portion A of the solder portion 36 does not contact the side surface 21b of the LED chip 21. As a result, as shown in FIG. 6, the transparent protective film 35 is interposed between the side surface 21b of the LED chip 21 and the solder portion 36. This improves adhesion between the transparent protective film 35 and the LED chip 21. As a result, the transparent protective film 35 can effectively protect the LED chip 21. Furthermore, because the transparent protective film 35 is interposed between the side surface 21b of the LED chip 21 and the solder portion 36, even if an operator touches the LED chip 21, the transparent protective film 35 can absorb the force applied to the LED chip 21, effectively preventing the LED chip 21 from peeling off from the LED illumination sheet 20.

[0065] 7, when viewed from the light-emitting surface 20a side, the portion of the solder portion 36 located on the side of the LED chip 21 is formed so as to surround part of the side surface 21b of the LED chip 21. This improves the bonding strength between the LED chip 21 and the solder portion 36. This makes it possible to prevent the LED chip 21 from peeling off from the solder portion 36.

[0066] On the other hand, as shown in FIG. 6 , the portion of the solder portion 36 located on the back surface 21c of the LED chip 21 extends continuously onto the metal wiring portion 32. As will be described later, this shape of the solder portion 36 is formed by pressing and crushing the solder 36a (see FIGS. 12(g)-(h)) against the LED chip 21 when forming the solder portion 36 by a reflow method. Although not shown, the portion of the solder portion 36 located on the back surface 21c of the LED chip 21 may be composed of multiple portions spaced apart from each other. That is, there may be an area on the back surface 21c of the LED chip 21 where the solder portion 36 is not formed. As described above, when forming the solder portion 36, the solder 36a is pressed and crushed by the LED chip 21. As a result, the solder 36a is pushed out from the back surface 21c of the LED chip 21, and an area on the back surface 21c of the LED chip 21 where the solder portion 36 is not formed may be formed. The soldering may be performed by a laser method.

[0067] (LED chip) The LED chip 21 is a light-emitting element that utilizes light emitted at a 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 top and bottom surfaces of the element, respectively, or a structure in which both a P-type electrode and an N-type electrode are provided on one surface of the element.

[0068] The LED chip 21 has a front surface 21a (the surface facing the light-emitting surface 20a), a side surface 21b (a surface perpendicular to the front surface 21a), and a back surface 21c (the surface opposite the light-emitting surface 20a). A light-emitting portion (phosphor) 21d is disposed on the front surface 21a of the LED chip 21. The light-emitting portion 21d transmits light from a light-emitting element (not shown) embedded in the LED chip 21 to the outside and protects the light-emitting element. The light-emitting portion 21d may be located over the entire front surface 21a of the LED chip 21 or in a portion of the front surface 21a (e.g., the center). The light-emitting portion 21d is preferably made of a resin or glass (refractive index: approximately 1.51) with a high optical transmittance and refractive index at the wavelength of light emitted by the LED chip 21. Examples of such resins include polycarbonate resin (refractive index: approximately 1.60), epoxy resin (refractive index: approximately 1.60), and silicone resin (refractive index: approximately 1.40). Furthermore, a phosphor may be dispersed in these resins to adjust the emission wavelength. The LED chip 21 may be provided with the above-mentioned light-emitting element, connection terminal, reflector, etc. in addition to the light-emitting portion 21d.

[0069] Furthermore, it is preferable to select LED chips 21 with high luminous efficiency. Specifically, it is preferable to use LED chips 21 with a luminous efficiency of 150 lm / W or more, and more preferably with a luminous efficiency of 180 lm / W or more. By increasing the luminous efficiency of the LED chips 21 to 150 lm / W or more, it is possible to reduce the number (density) of mounted LED chips 21 and reduce heat generated by Joule heat from the LED chips 21, which makes it less likely for variations in plant growth due to heat from the LED chips 21 to occur, thereby suppressing a decrease in yield.

[0070] As described above, the LED lighting sheet 20 has the LED chips 21 directly mounted on the metal wiring section 32, which has high heat dissipation properties. As a result, even when the LED chips 21 are arranged at high density, excess heat generated when the LED chips 21 are lit can be quickly diffused through the metal wiring section 32 and sufficiently dissipated to the outside of the LED lighting sheet 20 via the substrate film 31. This makes it less likely that variations in plant growth due to heat from the LED chips 21 will occur, and reduces yield declines.

[0071] (Light-reflective insulating protective film) The light-reflective insulating protective film 34 is a layer formed in an area excluding the area where the LED chip 21 is provided and the surrounding area. The light-reflective insulating protective film 34 is a so-called resist layer that has sufficient insulation properties to improve the migration resistance of the flexible wiring board 30, and is also a light-reflecting layer that has light reflectivity that contributes to improving the luminance of the light environment created by the LED illumination sheet 20.

[0072] The light-reflective insulating protective film 34 can be formed from various resin compositions containing a urethane-based resin or the like as a base resin and further containing a white pigment made of an inorganic filler such as titanium oxide. The base resin of the resin composition used to form the light-reflective insulating protective film 34 can be, in addition to a urethane-based resin, an acrylic polyurethane resin, a polyester resin, a phenolic resin, or the like. It is more preferable that the base resin of the resin composition forming the light-reflective insulating protective film 34 be the same or a similar resin as the resin composition forming the transparent protective film 35. As described below, it is preferable that the transparent protective film 35 be primarily made of an acrylic polyurethane resin. Therefore, when the base resin of the resin composition forming the transparent protective film 35 is an acrylic polyurethane resin, it is more preferable that the base resin of the resin composition forming the light-reflective insulating protective film 34 be a urethane-based resin or an acrylic polyurethane resin.

[0073] The inorganic filler to be contained as a white pigment in the resin composition that forms the light-reflective insulating protective film 34 may be at least one selected from titanium oxide, alumina, barium sulfate, magnesia, aluminum nitride, boron nitride, barium titanate, kaolin, talc, calcium carbonate, zinc oxide, silica, mica powder, powdered glass, powdered nickel, and powdered aluminum.

[0074] The thickness of the light-reflective insulating protective film 34 is 5 μm or more and 50 μm or less, and more preferably 7 μm or more and 20 μm or less. If the thickness of the light-reflective insulating protective film 34 is less than 5 μm, the light-reflective insulating protective film will be thin, particularly at the edge portions of the metal wiring portion 32, and if the metal wiring is not covered and is exposed, there is a high risk that the insulation properties will not be maintained. On the other hand, from the viewpoint of protecting the light-reflective insulating protective film 34 from bending of the substrate during handling, transportation, etc., the thickness of the light-reflective insulating protective film 34 is preferably 50 μm or less.

[0075] Furthermore, the light-reflective insulating protective film 34 preferably has an average light reflectance of 65% or more in the wavelength range of 400 nm or more and 780 nm or less, more preferably 70% or more, and even more preferably 80% or more. For example, by incorporating 20 parts by mass or more of titanium oxide per 100 parts by mass of a urethane-based or acrylic polyurethane base resin, the LED lighting sheet 20 can achieve the light reflectance of the light-reflective insulating protective film 34 of 75% or more when the thickness of the film is 8 μm.

[0076] (Transparent protective film) The transparent protective film 35 is formed on the outermost surface of the LED lighting sheet 20 so as to cover the LED chips 21. In this case, the transparent protective film 35 collectively covers the multiple LED chips 21 and extends continuously between adjacent LED chips 21. The transparent protective film 35 is waterproof and transparent. The waterproof property of the transparent protective film 35 prevents water from entering the LED lighting sheet 20 when it is used as a light source for plant growth. The transparent protective film 35 also prevents the LED chips 21 from peeling off from the LED lighting sheet 20.

[0077] The transparent protective film 35 can be formed from various resin compositions having an acrylic polyurethane resin or the like as a base resin. For example, the transparent protective film 35 may be formed from a two-component curing acrylic polyurethane resin containing fluorine. Furthermore, as the base resin of the resin composition used to form the transparent protective film 35, in addition to an acrylic polyurethane resin, a urethane resin, a polyester resin, a phenolic resin, or the like can be appropriately used. It is more preferable that the base resin of the resin composition forming the transparent protective film 35 is the same as or similar to the resin composition forming the light-reflective insulating protective film 34. A preferred specific combination is one in which the base resin of the resin composition forming the light-reflective insulating protective film 34 is a urethane resin, and the base resin of the resin composition forming the transparent protective film 35 is an acrylic polyurethane resin.

[0078] Next, the transparent protective film 35 according to this embodiment will be described in more detail with reference to FIG. 6. As shown in FIG. 6, the transparent protective film 35 according to this embodiment covers the entire surface 21a (the surface on the light-emitting surface 20a side) and side surfaces 21b of the LED chip 21, including the light-emitting portion 21d. In this case, the transparent protective film 35 includes a central portion 35a, a curved portion 35b, and a flat portion 35c. Of these, the central portion 35a covers the surface 21a, including the light-emitting portion 21d of the LED chip 21. The curved portion 35b is formed around the central portion 35a and covers the side surfaces 21b of the LED chip 21. The flat portion 35c is formed adjacent to the curved portion 35b and extends continuously to the curved portion 35b that covers the adjacent LED chip 21. In this embodiment, the central portion 35a covers the entire surface 21a of the LED chip 21. This protects the light-emitting portion 21d arranged on the surface 21a of the LED chip 21 from moisture that splashes during plant growth. Furthermore, because the central portion 35a covers the entire surface 21a of the LED chips 21, when the LED illumination sheet 20 is used in a plant cultivation factory, it is possible to prevent grown plants from coming into contact with the light-emitting portions 21d. Furthermore, because the central portion 35a covers the entire surface 21a of the LED chips 21, it is possible to prevent the light-emitting portions 21d of the LED chips 21 from falling onto the plants being grown, and it is possible to prevent the light-emitting portions 21d from coming into contact with the plants. This makes it possible to maintain the sanitary condition of the plants being grown in good condition.

[0079] Furthermore, the thickness of the central portion 35a may be formed so as to gradually increase toward the center of the LED chip 21 on the surface 21a of the LED chip 21. This allows the thickness of the portion of the central portion 35a that covers the light-emitting portion 21d that may be located approximately in the center of the surface 21a of the LED chip 21 to be increased. This makes it possible to more reliably protect the light-emitting portion 21d that may be located approximately in the center of the surface 21a of the LED chip 21 from moisture that scatters during plant growth.

[0080] Furthermore, the thickness of the thickest portion of the central portion 35a of the transparent protective film 35 is 5 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 making the thickness of the thickest portion of the central portion 35a 40 μm or less, the LED illumination sheet 20 can effectively maintain good flexibility, thinness, and lightness, as well as good optical properties required for plant cultivation applications. Furthermore, by making the thickness of the thickest portion of the central portion 35a 10 μm or more, the LED illumination sheet 20 can be provided with sufficient waterproofing required for plant cultivation applications.

[0081] The curved portion 35b of the transparent protective film 35 covers the entire side surface 21b of the LED chip 21. This prevents the LED chip 21 from peeling off from the solder portion 36 even if an operator touches the LED chip 21.

[0082] Furthermore, the thickness of the curved portion 35b may be formed to gradually increase as it approaches the LED chip 21. This makes it possible to prevent a large force from being locally applied to the joint between the LED chip 21 and the solder portion 36 even if an operator touches the LED chip 21, and more effectively prevent the LED chip 21 from peeling off from the solder portion 36.

[0083] Furthermore, the curved portion 35b has a concave shape that is recessed from the light-emitting surface 20a side toward the surface opposite to the light-emitting surface 20a in a cross section perpendicular to the light-emitting surface 20a of the LED illumination sheet 20. This effectively prevents the transparent protective film 35 from being damaged by force applied to the LED chips 21, even if an operator comes into contact with the LED chips 21. In this case, the radius of curvature r of the concave shape may be, for example, approximately 200 μm or more and 5000 μm or less.

[0084] Furthermore, the curved portion 35b covers the solder portion 36 located on the side of the LED chip 21. This protects the solder portion 36 from moisture that splashes during plant growth. Covering the solder portion 36 with the curved portion 35b of the transparent protective film 35 also prevents the grown plant from coming into contact with the solder portion 36. Covering the solder portion 36 with the curved portion 35b also prevents the solder portion 36 from peeling off from the LED chip 21. In particular, in this embodiment, the portion of the solder portion 36 located on the side of the LED chip 21 is formed in a substantially semicircular shape. This may reduce the bonding area between the portion of the solder portion 36 located on the side of the LED chip 21 and the side surface 21b of the LED chip 21. This may reduce the bonding strength between the portion of the solder portion 36 located on the side of the LED chip 21 and the side surface 21b of the LED chip 21. In this embodiment, the solder portion 36 is covered with the curved portion 35b of the transparent protective film 35, so that even if the portion of the solder portion 36 located on the side of the LED chip 21 is formed in a substantially semicircular shape, the solder portion 36 can be effectively prevented from peeling off from the LED chip 21. This prevents the solder from coming into contact with the plant, thereby maintaining good sanitary conditions for the plant being grown.

[0085] The flat portion 35c of the transparent protective film 35 has a substantially constant thickness. The thickness of the flat portion 35c is 5 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 making the thickness of the flat portion 35c 40 μm or less, the LED illumination sheet 20 can effectively maintain good flexibility, thinness, and lightness. Furthermore, by making the thickness of the flat portion 35c 5 μm or more, the LED illumination sheet 20 can be provided with sufficient waterproofing required for plant cultivation applications.

[0086] In this embodiment, the refractive index of the transparent protective film 35 constituting the protective portion 35A is a value between the refractive index of air (approximately 1.0) and the refractive index of the light-emitting portion 21d of the LED chip 21. That is, the refractive index of the transparent protective film 35 is greater than the refractive index of air but less than the refractive index of the light-emitting portion 21d. By setting the refractive index of the transparent protective film 35 between the refractive index of air and the refractive index of the light-emitting portion 21d, the refractive index can be gradually changed from the light-emitting portion 21d to the air. That is, as shown in FIG. 8 , light emitted from the light-emitting portion 21d of the LED chip 21 is partially reflected at the interface S1 between the light-emitting portion 21d and the transparent protective film 35, and further partially reflected at the interface S2 between the transparent protective film 35 and the air. In this case, by interposing the transparent protective film 35 between the light-emitting portion 21d and the air and setting the refractive index of the transparent protective film 35 to a value between the refractive index of air and the refractive index of the light-emitting portion 21d, the overall light reflectance can be reduced compared to a case where the transparent protective film 35 is not provided. This increases the transmittance of light from the LED chips 21, and the amount of light from the LED illumination sheet 20 can be increased.

[0087] Fig. 9 is a graph showing the change in light reflectance (vertical axis) from the light-emitting portion 21d of the LED chip 21 to the air when the refractive index (horizontal axis) of the transparent protective film 35 is changed. Fig. 9 shows the case where polycarbonate (refractive index: 1.60) is used as the material for the light-emitting portion 21d. As is clear from Fig. 9, the overall reflectance is lowest when the refractive index of the transparent protective film 35 is about 1.30, and the overall reflectance increases as the refractive index of the transparent protective film 35 increases from 1.30 to 1.60.

[0088] The refractive index of the transparent protective film 35 may be 1.60 or less, 1.58 or less, 1.56 or less, 1.50 or less, 1.45 or less, or 1.40 or less. When the upper limit of the refractive index of the transparent protective film 35 is set within the above range, the refractive index can be gradually changed from the light-emitting section 21d to the air. This reduces the overall light reflectance from the light-emitting section 21d to the air. As a result, the transmittance of light from the LED chips 21 is increased, and the amount of light from the LED lighting sheet 20 can be increased.

[0089] Fig. 10 is a graph showing the directivity characteristics of the LED chip 21. As is clear from Fig. 10, when the radiation angle from the LED chip 21 is within 30 degrees (π / 6), the illuminance of the light from the LED chip 21 is 85% or more.

[0090] Furthermore, as shown in FIG. 8, when the refractive index of air is N1, the refractive index of transparent protective film 35 is N2, the incident angle of light from transparent protective film 35 to air is θ1, and the incident angle of light from light emitting section 21d to transparent protective film 35 (the radiation angle of light from LED chip 21) is θ2, according to Snell's law, N1sinθ1=N2sinθ2 (1) where N1=1.0. As described above, if the radiation angle of light from the LED chip 21 is set to within 30 degrees (θ2=π / 6), then sinθ1=1 / 2(N2) (2) holds true.

[0091] Furthermore, as shown in FIG. 11, in order to reduce the dead space Sd (shaded area) between adjacent LED chips 21 where no light reaches, it is preferable that θ1 be approximately 45 degrees or greater. Therefore, according to the above formula (2), when θ1 = 45 degrees, the refractive index (N2) of the transparent protective film 35 is 1.414... Furthermore, as N2 increases, θ1 increases. Therefore, when N2 > 1.41, θ1 = 45 degrees or greater. For θ1 to be approximately 45 degrees or greater, N2 must at least be 1.39. Therefore, N2 may be 1.39 or greater, preferably 1.40 or greater, and even better still, 1.41 or greater.

[0092] The upper and lower limits of the refractive index of the transparent protective film 35 can be any combination of the above values. The refractive index of the transparent protective film 35 can be adjusted by changing the mixing ratio of the multiple types of resins that make up the transparent protective film 35.

[0093] The transparent protective film 35 preferably has good waterproof properties, and its surface may be hydrophilic or water-repellent. If the transparent protective film 35 is hydrophilic, when water adheres to the transparent protective film 35, the adhered water spreads along the surface of the transparent protective film 35. This prevents the adhered water from forming droplets and accumulating at positions on the surface 21a of the LED chip 21 corresponding to the light-emitting portions 21d. As a result, good optical properties of the LED lighting sheet 20 can be effectively maintained. However, while the hydrophilic property tends to lose its effectiveness due to the adhesion of dirt and other contaminants, if the transparent protective film 35 is water-repellent, the effect is more likely to be maintained, and good waterproof properties can be maintained for a long period of time.

[0094] The contact angle of the transparent protective film 35 constituting the protective part 35A with water may be greater than 20°, more preferably greater than 50°, and even more preferably greater than 80°. By setting the contact angle of the transparent protective film 35 with water within the above range, the water repellency of the transparent protective film 35 is improved, and water adhering to the surface of the transparent protective film 35 can be quickly removed. The contact angle of the transparent protective film 35 can be measured by dropping pure water on the sample surface and then measuring with a contact angle meter (manufactured by Kyowa Interface Science Co., Ltd., model number DROPMASTER500).

[0095] As an example, when an acrylic polyurethane resin was used as the material for transparent protective film 35 and the contact angle of transparent protective film 35 was measured using the contact angle meter described above, the following data was obtained. When this was calculated at ±4σ, the contact angle of transparent protective film 35 was 97.0°±8.5°.

[0096] [Table 1]

[0097] Furthermore, the water resistance of the LED lighting sheet 20 provided by the transparent protective film 35 is not particularly limited, as long as it is sufficient to prevent deterioration of the LED chips 21 when water for plant growth is sprayed onto the LED lighting sheet 20. Such water resistance preferably meets the waterproof and dustproof protection standard IPX4 or higher established by the IEC (International Electrotechnical Commission). Water resistance of IPX4 or higher is sufficient to prevent harmful effects on the LED chips 21 from water splashes from any direction. Specifically, this level of water resistance is sufficient to prevent harmful effects on the LED chips 21 when water is sprayed from a watering nozzle at a rate of 10 L / min over an entire range of ±180° from the normal direction of the LED lighting sheet 20 for 5 minutes.

[0098] (LED lighting sheet manufacturing method) Next, a method for manufacturing the LED illumination sheet 20 according to this embodiment will be described with reference to FIGS. 12(a) to 12(h).

[0099] First, a substrate film 31 is prepared (FIG. 12(a)). Next, a metal foil 32A such as copper foil, which will be the material for the metal wiring portion 32, is laminated on the surface of the substrate film 31 (FIG. 12(b)). The metal foil 32A is adhered to the surface of the substrate film 31 with an adhesive layer 33 such as a urethane adhesive. Alternatively, the metal foil 32A may be formed directly on the surface of the substrate film 31 by electroplating or a vapor-phase film-forming method (sputtering, ion plating, electron beam evaporation, vacuum evaporation, chemical vapor deposition, etc.). Alternatively, the metal foil 32A may be formed by directly welding the substrate film 31 to the metal foil 32A.

[0100] Next, an etching mask 37 patterned into the shape required for the metal wiring portion 32 is formed on the surface of the metal foil 32A (FIG. 12(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, and 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 by a printing technique such as an inkjet printer.

[0101] Next, the metal foil 32A located in the area not covered by the etching mask 37 is removed using an immersion liquid (FIG. 12(d)). As a result, the parts of the metal foil 32A other than the areas that will become the metal wiring portion 32 are removed.

[0102] Thereafter, the etching mask 37 is removed using an alkaline remover, thereby removing the etching mask 37 from the surface of the metal wiring portion 32 (FIG. 12(e)).

[0103] Next, a light-reflective insulating protective film 34 is formed on the metal wiring portion 32 (FIG. 12(f)). The method for forming the light-reflective insulating protective film 34 is not particularly limited as long as it is possible to uniformly apply the material resin composition that constitutes 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 applying a photosensitive insulating protective film material to the entire surface, exposing only the necessary areas to light through a photomask, and then developing the applied material.

[0104] Next, the LED chip 21, the regulator 45 components, and the connector 44 are mounted on the metal wiring portion 32 (FIGS. 12(g)-(h)). Note that in FIG. 12(h) and FIG. 12(i), the regulator 45 components are omitted for clarity. In this case, the LED chip 21 is joined to the metal wiring portion 32 by soldering via the solder portion 36. First, the solder 36a is stacked on the metal wiring portion 32 (FIG. 12(g)). Next, the LED chip 21 is placed on the solder 36a (FIG. 12(h)). As a result, the solder 36a is pressed against the LED chip 21 and is crushed, so that the solder 36a extends from the back surface 21c to the side surface 21b of the LED chip 21. Next, the solder 36a is heated in a reflow furnace (not shown), thereby mounting the LED chip 21 on the metal wiring portion 32 via the solder portion 36. In this case, the solder portion 36 is formed into a substantially semicircular shape at a portion located on the side of the LED chip 21. Note that this joining by soldering may be performed by a laser method or by joining with a conductive resin.

[0105] Next, a transparent protective film 35 is formed to cover the light-reflective insulating protective film 34, the LED chip 21, the regulator 45 components, and the connector 44 ( FIG. 12(i) ). The transparent protective film 35 is preferably formed by a spray coating method or a curtain coating method. The transparent protective film 35 can be formed by spraying a coating liquid for spray coating containing an acrylic polyurethane resin onto a desired region on the flexible wiring substrate 30 using a spray coater to form a coating film. The transparent protective film 35 can be formed by curtain coating, for example, dropping a coating liquid for curtain coating containing an acrylic polyurethane resin onto a desired region on the flexible wiring substrate 30 using a curtain coater to form a coating film. In these cases, the thickness of the transparent protective film 35 can be maintained within a predetermined range, and the shape of the transparent protective film 35 can easily conform to the shape of the LED chip 21. At this time, by appropriately adjusting the conditions for the spray coating method or curtain coating method, a transparent protective film 35 including a central portion 35a, curved portions 35b, and flat portions 35c is formed (see FIG. 6).

[0106] The LED illumination sheet 20 according to this embodiment can be manufactured not only by the method described above, but also by a known method for manufacturing a conventionally known flexible wiring substrate for LED chips or various LED modules in which LED chips are mounted on the substrate.

[0107] (Plant cultivation factories and plant cultivation shelves) 13 is a diagram showing a schematic configuration of a plant cultivation factory 90 using the LED illumination sheet 20 according to this embodiment. The plant cultivation factory 90 includes a building 91 and cultivation shelves 80 for a plurality of plants arranged inside the building 91.

[0108] As shown in FIG. 14 , the plant cultivation shelf 80 has multiple (four) support posts 82 and multiple boards 81 arranged at intervals along the support posts 82 in the vertical direction. A culture medium area for cultivating plants PL is provided on the upper surface of each board 81 except for the top board 81. The lower surface of each board 81 except for the bottom board 81 forms a ceiling surface relative to the board 81 located below it, and an LED illumination sheet 20 is arranged in parallel. In this case, the control unit 40 is located sufficiently far from the LED illumination sheet 20. This reduces the risk of variations in growth due to heat from the control unit 40 between plants PL located close to the control unit 40 and plants PL located far from it. Furthermore, the boards 81 and the LED illumination sheet 20 attached to the underside of the boards 81 form a shelf board 83 for the plant cultivation shelf. Alternatively, the boards 81 and the LED illumination modules 10 attached to the underside of the boards 81 form a shelf board 83 for the plant cultivation shelf. In this embodiment, there are also provided a shelf board 83 for such a plant growing shelf (FIG. 14), a plant growing shelf 80 (FIG. 14), and a plant growing factory 90 (FIG. 13) equipped with the plant growing shelf 80.

[0109] Because the LED illumination sheet 20 according to this embodiment is flexible and lightweight, it can be attached to the underside of each substrate 81 more easily than with conventional straight-tube lighting devices. Furthermore, because the LED illumination sheet 20 is flexible, it can be attached to ceiling surfaces of various sizes and shapes. As a result, the LED illumination sheet 20 according to this embodiment can be applied to various plant cultivation shelves 80 and plant cultivation factories 90.

[0110] Furthermore, the LED lighting sheet 20 is thinner than conventional straight-tube lighting devices. This allows the spacing between the substrates 81 in the vertical direction to be narrowed, and the number of substrates 81 included in each plant cultivation shelf 80 to be increased. As a result, the yield of plants PL per unit area can be increased.

[0111] As shown in FIGS. 15(a) and 15(b), the LED illumination sheet 20 may be disposed not only on the underside of the substrate 81 but also on the side of the substrate 81. The side LED illumination sheet 20 hangs down from the upper substrate 81 toward the lower substrate 81. In this case, as shown in FIG. 15(a), the LED illumination sheet 20 may reach the lower substrate 81. Alternatively, as shown in FIG. 15(b), the LED illumination sheet 20 may cover only the upper side of the space between the upper and lower substrates 81 without reaching the lower substrate 81. In this way, by disposing the LED illumination sheet 20 on the side of the substrate 81, the amount of light at the periphery of the substrate 81, where illuminance tends to be weak, can be compensated for, thereby making the brightness of the LED illumination sheet 20 uniform across the surface. As a result, plant growth can be made uniform across the surface, improving the yield of the plants being grown.

[0112] As described above, according to this embodiment, the LED illumination sheet 20 includes the protective portion 35A that covers the light-emitting portions 21d of the LED chips 21 and protects the LED chips 21. This prevents the LED chips 21 from peeling off from the LED illumination sheet 20 even if a worker or the like touches the LED chips 21 inside the plant cultivation factory 90. This prevents the LED chips 21 from falling onto the plants being grown, and prevents the light-emitting portions 21d of the LED chips 21 from coming into contact with the plants. This allows the plants being grown to be kept in good sanitary condition.

[0113] Furthermore, according to this embodiment, the refractive index of the protective portion 35A is between the refractive index of air and the refractive index of the light-emitting portion 21d of the LED chip 21. In particular, the refractive index of the protective portion 35A is preferably 1.39 or more and 1.60 or less. This allows the refractive index of light to gradually change from the light-emitting portion 21d of the LED chip 21 to the air. This reduces the overall light reflectance from the light-emitting portion 21d of the LED chip 21 to the air, improving the transmittance of light from the LED chip 21 and increasing the amount of light. In this way, increasing the amount of light from the LED illumination sheet 20 improves plant growth efficiency. As a result, the amount of plants grown can be increased while suppressing a decrease in the yield of the plants grown, resulting in a good yield of plants.

[0114] Furthermore, according to this embodiment, the contact angle of the protective portion 35A with respect to water is greater than 20°, and preferably equal to or greater than 80°. This improves the water repellency of the transparent protective film 35, and allows water adhering to the surface of the transparent protective film 35 to be quickly removed. As a result, the LED lighting sheet 20 can effectively maintain good optical properties.

[0115] According to the present embodiment, the protective portion 35A covers the solder portion 36 located on the side of the LED chip 21. This protects the solder portion 36 from moisture that scatters during plant growth and prevents the solder portion 36 from being short-circuited by moisture. Covering the solder portion 36 with the protective portion 35A also prevents the grown plant from coming into contact with the solder portion 36. Covering the solder portion 36 with the protective portion 35A also prevents the solder portion 36 from peeling off from the LED chip 21. In particular, in this embodiment, the portion of the solder portion 36 located on the side of the LED chip 21 is formed in a substantially semicircular shape. This may reduce the bonding strength between the portion of the solder portion 36 located on the side of the LED chip 21 and the side surface 21b of the LED chip 21. In this embodiment, the solder portion 36 is covered with the transparent protective film 35, which effectively prevents the solder portion 36 from peeling off from the LED chip 21, even if the portion of the solder portion 36 located on the side of the LED chip 21 is formed in a substantially semicircular shape. This prevents the solder from coming into contact with the plant. This allows the plant to be kept in good sanitary condition.

[0116] Furthermore, according to this embodiment, the central portion 35a covers the entire surface 21a of the LED chip 21. This ensures that the light-emitting portion 21d, which may be located approximately in the center of the surface 21a of the LED chip 21, is protected from moisture that may scatter during plant growth. Furthermore, because the central portion 35a covers the entire surface 21a of the LED chip 21, grown plants are prevented from coming into contact with the light-emitting portion 21d when the LED illumination sheet 20 is used in a plant growth factory. Furthermore, because the central portion 35a covers the entire surface 21a of the LED chip 21, the light-emitting portion 21d of the LED chip 21 is prevented from falling onto the plants being grown, preventing the light-emitting portion 21d from coming into contact with the plants. This ensures that the plants being grown are kept in good sanitary condition.

[0117] Furthermore, according to this embodiment, the thickness of the central portion 35a is formed to gradually increase toward the center of the LED chip 21. This allows the thickness of the portion of the central portion 35a that covers the light-emitting portion 21d that may be located approximately in the center of the surface 21a of the LED chip 21 to be increased. This makes it possible to more reliably protect the light-emitting portion 21d that may be located approximately in the center of the surface 21a of the LED chip 21 from moisture that is dispersed during plant growth.

[0118] Furthermore, according to this embodiment, the curved portion 35b of the transparent protective film 35 covers the entire side surface 21b of the LED chip 21. This prevents the LED chip 21 from peeling off from the solder portion 36 even if an operator touches the LED chip 21.

[0119] Furthermore, according to this embodiment, the thickness of the curved portion 35b is formed to gradually increase as it approaches the LED chip 21. As a result, even if an operator touches the LED chip 21, it is possible to prevent a large force from being locally applied to the joint between the LED chip 21 and the solder portion 36, and it is possible to more effectively prevent the LED chip 21 from peeling off from the solder portion 36.

[0120] Furthermore, according to this embodiment, the curved portion 35b has a concave shape that is recessed from the light-emitting surface 20a side toward the surface opposite to the light-emitting surface 20a in a cross section perpendicular to the light-emitting surface 20a of the LED illumination sheet 20. This effectively prevents the transparent protective film 35 from being damaged by a force applied to the LED chips 21, even if an operator touches the LED chips 21.

[0121] Furthermore, according to this embodiment, the curved portion 35b covers the solder portion 36 located on the side of the LED chip 21. This makes it possible to protect the solder portion 36 from moisture that splashes when a plant is being grown. Furthermore, because the solder portion 36 is covered by the curved portion 35b, it is possible to prevent the grown plant from coming into contact with the solder portion 36. Furthermore, because the solder portion 36 is covered by the curved portion 35b, it is possible to prevent the solder portion 36 from peeling off from the LED chip 21. This makes it possible to prevent the solder from coming into contact with the plant, and to maintain good hygiene for the plant being grown.

[0122] Furthermore, according to this embodiment, in a cross section perpendicular to the light-emitting surface 20a of the LED illumination sheet 20, the thickest portion A of the solder portion 36 does not contact the side surface 21b of the LED chip 21. This allows the transparent protective film 35 to be interposed between the side surface 21b of the LED chip 21 and the solder portion 36, thereby improving adhesion between the transparent protective film 35 and the LED chip 21. As a result, the transparent protective film 35 can effectively protect the LED chip 21. Furthermore, because the transparent protective film 35 is interposed between the side surface 21b of the LED chip 21 and the solder portion 36, even if an operator touches the LED chip 21, the transparent protective film 35 can absorb the force applied to the LED chip 21, effectively preventing the LED chip 21 from peeling off from the LED illumination sheet 20.

[0123] Furthermore, according to this embodiment, when viewed from the light-emitting surface 20a side, the portion of the solder portion 36 located to the side of the LED chip 21 is formed so as to surround part of the side surface 21b of the LED chip 21. This improves the bonding strength between the LED chip 21 and the solder portion 36. This makes it possible to prevent the LED chip 21 from peeling off from the solder portion 36.

[0124] Furthermore, according to this embodiment, the transparent protective film 35 covers the light-reflective insulating protective film 34. This allows the transparent protective film 35 to protect the light-reflective insulating protective film 34.

[0125] Furthermore, according to this embodiment, the protective portion 35A covers the entire surface 21a and side surfaces 21b of the LED chip 21. This ensures that the LED chip 21 is protected from moisture that may scatter during plant growth. Furthermore, since the protective portion 35A covers the entire surface 21a of the LED chip 21, the sanitary condition of the plant being grown can be maintained even better.

[0126] Furthermore, according to this embodiment, ten or more LED chips 21 are arranged in series, and four or more rows of the LED chips 21 are arranged in parallel. This allows the LED chips 21 to be arranged uniformly within the plane, and the LED chips 21 to be arranged in parallel, thereby dispersing the risk of damage to the LED chips 21.

[0127] Furthermore, according to this embodiment, the thickness of the LED lighting sheet 20 at its thickest point is 5 mm or less, so by reducing the distance between the upper and lower substrates 81 of the plant cultivation shelf 80 and increasing the number of substrates 81, it is possible to increase the plant yield per unit area.

[0128] Furthermore, according to this embodiment, the control unit 40 is externally connected to the LED illumination sheet 20, so that the control unit 40 can be separated from the LED illumination sheet 20 to prevent the heat from the control unit 40 from affecting the plants.

[0129] Furthermore, according to this embodiment, a constant voltage is applied to the LED illumination sheet 20 from the control unit 40, which increases the integrated amount of light per unit time from the LED chips 21 and promotes plant growth.

[0130] Furthermore, according to this embodiment, the control unit 40 is capable of controlling the dimming of the LED chip 21, and therefore the intensity of the light from the LED chip 21 can be adjusted according to the growth stage of the plant.

[0131] In the above-described embodiment, the transparent protective film 35 is formed by spray coating or curtain coating, but the present invention is not limited to this. For example, the transparent protective film 35 may be formed by attaching a resin film to the LED chip 21 or the light-reflective insulating protective film 34. In this case, the resin film may be made of a vinyl chloride-based or fluorine-based resin, or a general resin such as polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), polyethylene naphthalate (PEN), or polyimide (PI). In this way, the above-described effects can be obtained even when the transparent protective film 35 is made of a resin film.

[0132] It is also possible to combine the multiple components disclosed in the above-described embodiments and modifications as needed, or to delete some of the components disclosed in the above-described embodiments and modifications. [Explanation of symbols]

[0133] 10 LED lighting modules 20 LED lighting sheets 20a Light-emitting surface 21 LED chips 21a surface 21b Side 21c back side 21d Light-emitting part 22 Metal wiring section 30 Flexible wiring board 31 Substrate film 32 Metal wiring section 33 Adhesive layer 34 Light-reflective insulating protective film 35 Transparent protective film 36 Soldering part 40 Control Unit 41 Power input section 42 AC / DC converter 43 PWM control unit 44A 1st Connector 44B 2nd connector 45 Regulator 46 Power Supply Line 80 Plant Growing Shelf 81 Circuit Board 82 Pillars 83 Shelf for plant growing shelf 90 Plant Growing Factory 91 Building

Claims

1. An LED lighting sheet for growing plants and animals, A substrate; a metal wiring portion formed on the surface of the substrate; an LED chip having a light-emitting portion mounted on the metal wiring portion; a protective portion that covers at least a portion of the light-emitting portion of the LED chip and protects the LED chip; the refractive index of the protective portion is between the refractive index of air and the refractive index of the light-emitting portion of the LED chip; the LED chip is mounted on the metal wiring portion via an electrical connection portion, the electrical connection portion extending from a rear surface to a side surface of the LED chip, and the protective portion covering the electrical connection portion located on a side surface of the LED chip; An LED lighting sheet for growing animals and plants, wherein the thickest part of the electrical connection part does not contact the side surface of the LED chip, and the protective part is interposed between the side surface of the LED chip and the electrical connection part.

2. 2. The LED illumination sheet for growing animals and plants according to claim 1, wherein the refractive index of the protective portion is 1.39 or more and 1.60 or less.

3. 3. The LED illumination sheet for growing animals and plants according to claim 1, wherein the protective portion has a contact angle with water of more than 20 degrees.

4. 4. The LED illumination sheet for growing animals and plants according to claim 3, wherein the contact angle of the protective portion with respect to water is 50 degrees or more.

5. 5. The LED illumination sheet for growing animals and plants according to claim 3, wherein the contact angle of the protective portion with respect to water is 80 degrees or more.

6. 6. The LED illumination sheet for growing animals and plants according to claim 1, wherein the protective portion includes a central portion covering at least a portion of the surface of the LED chip, a curved portion covering at least a portion of the side surface of the LED chip, and a flat portion formed adjacent to the curved portion.

7. further comprising a light-reflective insulating protective film disposed so as to cover the metal wiring portion; The LED illumination sheet for growing animals and plants according to claim 1 , wherein the protective portion covers the light-reflective insulating protective film.

8. An LED lighting module for growing plants and animals, The LED illumination sheet for growing animals and plants according to any one of claims 1 to 7; a control unit electrically connected to the LED illumination sheet for growing animals and plants, The control unit is an LED lighting module for growing animals and plants that is externally connected to the LED lighting sheet for growing animals and plants.

9. A shelf board for growing plants and animals, A substrate; A shelf board for growing animals and plants, comprising an LED lighting sheet for growing animals and plants described in any one of claims 1 to 7 or an LED lighting module for growing animals and plants described in claim 8 attached to the substrate.

10. A growing shelf for plants and animals, Equipped with shelves, The shelf board is provided with an LED lighting sheet for growing animals and plants as described in any one of claims 1 to 7 or an LED lighting module for growing animals and plants as described in claim 8 attached to the underside of a substrate, the shelf board being an animal and plant growing shelf.

11. Buildings and An animal or plant growing factory comprising: a growing shelf for growing animals or plants according to claim 10 arranged inside the building.

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