JP5597003B2 - Plant growth lighting device and plant growth device using the same - Google Patents

Description

  The present invention relates to an illuminating device used in a plant seedling growing apparatus for plants such as flowers and vegetables.

  Conventionally, lighting such as fluorescent lamps has been used as an illumination device for plant culture and seedling growth. However, there are problems with leaf burning due to heat generated by the illumination device as seedlings grow, However, there is a problem that the increase in the number of steps is limited by the thickness of the lighting device. In order to solve these problems, in recent years, an illumination device using a surface light source having a small thickness and excellent uniformity has been put into practical use (Patent Documents 1 and 2). The surface light source is composed of a light guide plate having a light source disposed at the end, and a technology developed as an illumination device for a liquid crystal display (LCD) or the like, for example, a technology combining a reflector, a diffusion sheet, and the like is applied.

  However, LCDs, etc. emphasize the characteristics such as high brightness and wide viewing angle, while lighting devices used in plant growing devices are necessary for growing seedlings for plants arranged at a predetermined interval from the lighting device. It is important that a sufficient amount of light is irradiated and the light amount distribution is uniform. In patent document 1, in order to make illumination intensity uniform, it has been proposed to dispose a light diffusion sheet as a light control unit on the lower side of the light guide plate of the lighting device. However, when the light is diffused and uniformed, it is difficult to keep the same amount of light around the light guide plate as inside. For this reason, the plant culture apparatus using the illumination device described in Patent Document 1 has a bottom surface area on which the culture vessel is placed, which is less than the area of the ceiling opening where the illumination device is installed, and the end of the illumination device that is difficult for light to reach. Plants are not placed directly underneath.

  In Patent Literature 2, in the lighting device of the plant seedling storage shelf, printing is performed on the back surface of the light guide plate so as to achieve substantially the same illuminance on the surface on which the seedling box is placed, and the center portion It has been proposed that the brightness be increased concentrically from the periphery to the periphery.

JP 2004-49211 A JP 2001-28946 A

  In the plant seedling growing device, the shelves on which seedlings are placed are multi-staged in order to use the space efficiently, but in order to achieve further efficiency, the space utilization rate on the plane of the shelf is increased and the number of stages is increased. There is a request. Further, in the plant seedling growing apparatus, not only the surface on which the seedling is placed (medium surface) but also the uniformity of the amount of light in the plane parallel to the medium surface is required over the range of the length at which the seedling grows.

  In the lighting device that improves the uniformity by utilizing the diffusion of light as described in Patent Document 1, a highly uniform illuminance is obtained in the vicinity of the lighting device, but the distance between the illuminated plant and the lighting device is small. When separated, the difference in illuminance increases near the center and the periphery. For this reason, the amount of light is reduced just below the periphery of the lighting device compared to the inner part, and in order to maintain the uniformity of the entire seedling container, it is necessary to adopt a seedling container whose bottom area is smaller than the area of the lighting device There is a limit to the space utilization rate in the plane direction.

  In the technique described in Patent Document 2, the amount of light can be made uniform to some extent on the surface on which the seedling is placed, but since the luminance at the center is lower than that at the periphery, the amount of light is near the surface near the lighting device. The uniformity of is reduced. Accordingly, when the seedling grows up and approaches the lighting device, the uniformity of the light quantity cannot be maintained. That is, in the techniques described in Patent Document 1 and Patent Document 2, there is a problem that there is a difference in the light uniformity depending on the distance from the lighting device, and the light uniformity cannot be maintained as the seedling grows. Moreover, in the technique described in Patent Document 2, it is necessary to place a certain distance between the lighting device and the seedling in order to maintain the uniformity of the amount of light, and there is a limit to the increase in the number of stages when the number of stages is increased. .

  The present invention provides an illuminating device that improves the uniformity of the amount of light in a plane parallel to the medium surface over a range of lengths of seedlings to grow, and has little variation in seedling growth and at the time of seedling growth. An object of the present invention is to provide a plant growing apparatus capable of increasing the space utilization rate of the plant.

  In order to solve the above-described problems, according to the present invention, the following plant growth lighting device and plant growth device are provided.

  That is, the illuminating device of the present invention has a light guide plate and a light source disposed at least at one end of the light guide plate, and the light from the light guide plate is provided in a partial region of the light emitting surface along the edge of the light guide plate. The light control means which controls this in the direction orthogonal to the light-projection surface of a light-guide plate is arrange | positioned. Or the illuminating device of this invention arrange | positions the lighting unit which has a light-guide plate and the light source arrange | positioned at least at one end of the light-guide plate in the surface direction of a light-guide plate, and is comprised with a some illumination unit A light control means for controlling light from the light guide plate in a direction orthogonal to the light output surface of the light guide plate is disposed in a partial region along the edge of the output surface.

  In the plant growing lighting device of the present invention, for example, the light control means is a prism sheet. The prism sheet has, for example, a prism surface in which a plurality of triangular prisms are arranged in parallel, and is arranged on the light emitting surface so that the triangular prisms are parallel to the edge.

  In the plant growth lighting device of the present invention, for example, the light exit surface has a polygonal shape, and is arranged along one side at a corner where one side and a side adjacent thereto intersect. The first prism sheet and the second prism sheet arranged along the adjacent sides are arranged so as to cross each other.

  In the plant growth lighting device of the present invention, for example, the light source is an LED.

  The plant growing device of the present invention includes a frame including a plurality of support columns, a lighting device fixed to the upper portion of the frame, and a seedling shelf installed at the lower portion of the frame. The illumination device of the present invention is provided. Alternatively, the plant growing device of the present invention is fixed to the upper part of each of a frame including a plurality of support columns, a plurality of seedling shelves arranged at intervals in the vertical direction within the frame, and a plurality of seedling shelves. The illumination device of the present invention described above is provided as the illumination device.

  In the plant growing device of the present invention, preferably, the seedling rack and the light emitting surface of the lighting device have substantially the same area.

  According to the plant growth lighting device of the present invention, by controlling the light distribution only in the peripheral portion of the light guide plate, the light is guided between the lighting device and the irradiated plant without reducing the light amount of the entire lighting device. The uniformity of the amount of light in a plane parallel to the optical plate can be improved. Therefore, the amount of light necessary for growth can be given to all plants under the lighting device until they grow from the time of seedling and approach the lighting device, and variations in growth, particularly poor growth in the peripheral portion, can be eliminated. . In addition, when a plurality of seed beds are laid down to form a large-area plant growing device, the filling rate of the seed beds arranged in the same plane can be increased.

  In addition, since the uniformity of the in-plane light quantity can be achieved over a relatively long range from the lighting device, the distance between the lighting device and the nursery can be minimized according to the growth of the plant, More stages can be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows 1st Embodiment of the illuminating device of this invention, (a) is a top view, (b) is a partial sectional side view. The perspective view which shows the prism sheet used for the illuminating device of FIG. It is a figure explaining the breadth of the light of the illuminating device of FIG. 1, (a) is a breadth of a horizontal direction, (b) is a figure which shows the breadth of a perpendicular direction. (A), (b) is a figure which respectively shows the breadth of light of an illuminating device using the light-guide plate which does not arrange | position a prism sheet, and illumination intensity distribution. The figure which shows illuminance distribution when a prism sheet is arranged on the entire surface of the light guide plate (A), (b) is a figure which respectively shows 2nd Embodiment of the illuminating device of this invention, and is the figure seen from the light-projection surface of the illuminating device. The figure which shows embodiment of the plant growing apparatus of this invention It is a figure explaining the measuring method of the photon flux density in an Example, (a) is a figure which shows arrangement | positioning of a photon sensor, (b) is a figure which shows a photon measurement point. The graph which shows the illumination intensity distribution in the surface of distance 200mm from the illuminating device in Example 1 and Comparative Examples 1 and 2. The graph which shows the illumination intensity average value according to the distance from the illuminating device in Examples 1-3. The graph which shows the dispersion | variation in the illumination distribution according to the distance from the illuminating device in Examples 1-3.

<Lighting device>
An embodiment of a plant-growing lighting device of the present invention will be described with reference to the drawings.

<First embodiment>
1A and 1B are diagrams showing a first embodiment of a plant-growing lighting device of the present invention, in which FIG. 1A is a view seen from the light emitting surface side of the lighting device, and FIG. The illuminating device 10 mainly includes a housing 11 having a large opening on a light emission surface (lower side in the drawing), a light source unit 20 fixed to an end portion of the housing 11, and an end portion of the housing 11. The light guide plate unit 30 is fixed to the inner bottom surface, and the waterproof glass 13 covers the light guide plate unit 30.

  The housing 11 includes a main body part 11a to which the light source unit 20 and the light guide plate unit 30 are fixed, and a lid part 11b that covers the periphery of the light emitting surface side of the main body part 11a. The lid portion 11 b is formed with an opening that is substantially the same size as the light guide plate unit 30, and the end portion on the opening side is fixed to the outer surface end portion of the waterproof glass 13 via the waterproof packing 15. With this structure, water does not enter from the outside into the internal space formed by the casing 11 (main body and lid) and the waterproof glass 13, that is, the space where the light guide plate unit 30 and the light source unit 20 are arranged. It has become.

  In this embodiment, the light source unit 20 includes an LED 21, a substrate 22 for connecting the LED 21 to an external power source (not shown), and a heat radiating plate 23 for radiating heat generated from the LED 21. Are arranged so as to be positioned closest to the end of the light guide plate unit 30. The LED 21 having a predetermined wavelength is selected according to the growth time and characteristics of the plant irradiated with light from the lighting device. In FIG. 1B, which is a side sectional view, only one LED element is shown, but a linear light source in which a plurality of LED elements are arranged in a line along one side of the light guide plate is used.

  The light guide plate unit 30 includes a light guide plate 31, a reflection sheet 33 attached to one surface thereof, and a prism sheet 35 attached to the other surface. The reflection sheet 33 returns light emitted from the light guide plate 31 to the light guide plate 31 side, and is made of a highly reflective material such as a white resin sheet or a metal foil film such as Al. The surface opposite to the surface of the light guide plate to which the reflection sheet 33 is attached is the light exit surface. The light guide plate 31 is made of a material having excellent translucency such as glass or acrylic resin, and a light output surface on which a pattern such as a dot is printed can be used. Also, depending on the arrangement of the light source unit 20, for example, depending on whether the light source unit 20 is arranged on all four sides of the light guide plate 31 or on one side to three sides, the thickness depends on the distance from the light source unit. It is possible to use one having an inclination or one having a printed pattern formed thereon. In the embodiment shown in FIG. 1, the light source unit 20 is arranged on four sides of the light guide plate 31, and a flat light guide plate 31 having no change in thickness is used.

  As shown in FIG. 2, the prism sheet 35 is a sheet having a prism surface having a shape in which a plurality of parallel cross-sectional V-shaped grooves are formed on one surface and a plurality of triangular prisms are arranged in parallel. Is attached to the light guide plate 31 so as to face downward. The apex angle formed by the adjacent V-shaped grooves of the prism sheet 35 is 70 ° to 120 °, which refracts light in various directions incident from the side opposite to the prism surface (that is, the light guide plate side). In particular, light having a component in a direction perpendicular to the groove is emitted in a direction (vertical direction) perpendicular to the prism surface.

  The prism sheet 35 having such a structure is attached with a predetermined width along the four sides of the rectangular light guide plate 31 as shown in FIG. At this time, the side and the V-shaped groove are arranged in parallel. The prism sheet 35 attached along one side and the prism sheet 35 attached along the side adjacent to the side are arranged so as to intersect each other at a corner where both sides intersect. The width of the prism sheet 35, that is, the width from the edge of the region where the prism sheet of the light guide plate 31 is attached, is preferably 6% or more (the width of both sides) with respect to the width of the light guide plate 31 (the width of the light emitting surface). The total of the regions is 12% or more), more preferably 10% or more (the total of the regions on both sides is 20% or more). Further, it is preferably 30% or less (60% or less in total of the regions on both sides), more preferably 25% or less (50% or less in total of the regions on both sides).

  The spread of light when the prism sheet is arranged in this way will be described with reference to FIG. 3A shows the spread of light in the horizontal direction, and FIG. 3B shows the spread of light in the vertical direction. For reference, the light spread and illuminance distribution when no prism sheet is used are shown in FIGS. 4A and 4B, and the two prism sheets are arranged on the entire surface of the light guide plate with the directions of the prisms orthogonal to each other. The illuminance distribution is shown in FIG.

In the state without the prism sheet, as shown in FIG. 4A, the light emitted from the light guide plate 31 is uniformly diffused from the center to the periphery of the light guide plate, and is guided at a predetermined distance from the light guide plate. As shown in FIG. 4B, the illuminance on the plane parallel to the light plate is the highest at the center of the light guide plate, and shows a distribution in which the illuminance decreases at the peripheral part (particularly at the four corners).
On the other hand, when the prism sheet is arranged on the entire surface, the direction of the light diffused by the prism sheet can be refracted in the vertical direction, so that the uneven illuminance distribution in the central portion and its periphery can be eliminated. Originally, the amount of light that should reach the peripheral portion is reduced by the diffusion of light, and the illuminance is reduced in the peripheral portion as shown in FIG.

  On the other hand, when the prism sheet is disposed along the periphery of the light guide plate (zones A and B), as shown in FIGS. 3A and 3B, in the portion where the prism sheet is not disposed, The light emitted from the light guide plate 31 is uniformly diffused from the center C toward the periphery (zones A and B), but in the zone B where the prism sheet is disposed, the component in the direction orthogonal to the prism is caused by the prism sheet. Refracted vertically. That is, the light travels directly downward in FIG. In the zone B, the component in the direction parallel to the prism is directed to both ends of the prism sheet along the direction, but is perpendicular to the prism sheet disposed in the four corners (zone A) and orthogonal to the direction. Refracted. As a result, most of the diffused light is directed in the vertical direction in the peripheral portions (zones A and B), there is little leakage of light from the peripheral portions to the outside, and uniform illuminance is obtained as a whole. In particular, as shown in FIG. 4B, the illuminance can be increased at four corners where the illuminance is significantly reduced.

  According to the present embodiment, by arranging the prism sheet 35 in a partial region along the end of the light exit surface of the light guide plate, the uniformity of the light quantity distribution on the surface relatively far from the illumination device is improved. In addition, it is possible to reduce the decrease in the amount of light as compared with the case where it is arranged over the entire surface. Moreover, the amount of prism sheet used is small.

  Further, since the amount of light spreading outward from the periphery of the light guide plate unit 30 can be reduced, a uniform light quantity distribution is achieved over a relatively long range from the vicinity of the light guide plate unit 30 including the prism sheet 35 to a position away from it. be able to.

<Second embodiment>
As a second embodiment of the illumination device of the present invention, an embodiment in which the present invention is applied to an illumination device in which a plurality of surface light source units are connected will be described with reference to FIG.
FIG. 6 is a view of the illumination device of the present embodiment as viewed from the light emitting surface side, where (a) is an illumination device in which four illumination units 10 ′ are connected, and (b) is in connection with two light source units 10 ′. The lighting device. However, the number of units to be connected is not limited to that shown in the figure, but is arbitrary.

  In the first embodiment, prism sheets are arranged along the four sides of a single light guide plate. However, in this embodiment, the shape of the entire lighting device is arranged along the periphery of the shape. Place a prism sheet. Also in this case, for example, when the shape is a quadrangle, the prism orientation of the prism sheet is arranged along each side, and the corners are arranged so as to intersect each other at the corners. In the four-unit illumination device shown in (a), each unit has a prism sheet arranged only on two sides that are the periphery of the illumination device, and the two prism sheets are overlapped at the corners. . In the two-unit illumination device shown in (b), prism sheets are respectively arranged on three sides that are the periphery of the illumination device. Except for the arrangement of the prism sheet, the structure of the illumination unit 10 'is the same as that of the illumination device shown in FIG.

  Also in the illumination device of this embodiment, similarly to the illumination device of the first embodiment, the light emitted from the light guide plate and diffused in the peripheral direction of the illumination device is refracted in the vertical direction by the prism sheet. A uniform light amount distribution can be obtained in a plane parallel to the light guide plate over a long range from the immediate vicinity of the lighting device (light guide plate) without reducing the light amount directly below.

  In addition, although the case where LED was used as a light source was demonstrated in the above embodiment, a light source is not limited to LED, It is also possible to use well-known light sources, such as a fluorescent lamp and a cold cathode fluorescent lamp. Even in such a case, the light source part is located at a position off the surface on which the plant is placed, so that the problem of leaf scalding can be avoided, and it does not hinder multi-stage due to the thickness of the light source.

<Plant growing device>
Next, the plant growing apparatus of the present invention will be described. The plant growing device of the present invention uses the above-described lighting device of the present invention as a lighting device, and, depending on the scale and size, a lighting device composed of a single light guide plate unit or a plurality of lighting units Or a lighting device in which they are appropriately combined can be used. Hereinafter, an embodiment in which the present invention is applied to a hydroponic cultivation apparatus will be described.

  FIG. 7 is a diagram showing a partial outline of a plant cultivation apparatus for hydroponics. This plant cultivation apparatus 70 includes a plurality of shelf boards 71, and columns 73 that support the shelf boards 71 at predetermined intervals. A hydroponic water tank 75 installed on each shelf 71 and a lighting device 77 fixed to the lower portion of the shelf 71 are provided.

  The illuminating device 77 has a structure in which a light source (LED) is fixed to an end portion of one light guide plate and a prism sheet is attached to the peripheral portion of the light guide plate as shown in FIG. A plurality of horizontal plates 74 are fixed to the column 73 in parallel with the shelf plate 73, and the column 73 of the plant growing device 70 is configured by the column 73 and the horizontal plate 74. The lighting device 77 is fixed to the shelf plate 73 by fitting into a groove formed between the horizontal plate 74 and the shelf plate 73. In this state, the portion of the heat sink included in the light source unit is located in the groove, and the heat generated from the light source is released from the heat sink through the support column 73. Therefore, even if the distance from the lighting device 77 becomes closer as the plant 50 grows, the plant 50 can be prevented from causing leaves or burns due to heat generated from the lighting device 77.

  The light is emitted from the illumination device 77 in a distribution as shown in FIG. 3, and as a result, a surface having the same area as that of the light guide plate unit from the shelf plate 73 surface to the light guide plate unit surface of the illumination device 77. The amount of light necessary for plant growth can be ensured and a highly uniform illuminance distribution can be obtained. Therefore, the plant 50 planted in the water tank 75 placed on the shelf board 74 can grow almost uniformly from the initial stage of growth until it grows to a predetermined length.

  According to such a plant growing apparatus of this embodiment, since the size of the lighting device and the area where the plant can grow without variation in growth can be matched, waste of the plant arrangement space in the plane can be eliminated. . In addition, even in the vertical direction, the illuminance distribution in the horizontal plane can be made uniform over a relatively long distance. Therefore, compared to the conventional plant growing apparatus in which the illuminance distribution in the horizontal plane is not uniform in the vertical direction, the shelf board. Can be shortened, and the number of stages can be increased.

Examples of the present invention will be described below.
<Example 1, Comparative Examples 1 and 2>
On the other side of the light guide plate (acrylic plate) with a reflection sheet laminated on one side, a prism film (brightness enhancement film, product name: BEF2 manufactured by 3M USA) was pasted along the four sides of the light guide plate. In the part, two prism films were overlapped. Using this light guide plate with a prism film, an illumination device (size: 600 mm × 600 mm) having the structure shown in FIG. 1 was produced. As the light source, 400 surface mount type LEDs were used. The size of the light emitting surface (light emitting surface) of this lighting device is 559 mm × 559 mm.

  The photon flux density in a plane parallel to the light emitting surface was measured at a distance of 0 mm, 50 mm, 100 mm, and 200 mm from the light emitting surface of the illumination device. For the measurement, as shown in FIG. 8A, a measuring tool 80 in which a photon sensor 83 (LI-COR, LI-190SA) movable along a frame is installed under a frame 81 having a width of 3 cm is used. The illuminating device 10 was installed so that the light emitting surface thereof faced upward, and the photon flux density at a plurality of points was measured while changing the position of the photon sensor 83 with respect to the illuminating device 10. As shown in FIG. 8B, the measurement points were 36 points on a matrix arranged at 100 mm intervals in the vertical and horizontal directions on a measurement surface of 600 mm × 600 mm.

  A lighting device manufactured in the same manner as in Example 1 except that no prism film is used is referred to as Comparative Example 1, and two prism films are adhered to the entire surface of the same light guide plate as in Example 1 so that the directions of the prisms are orthogonal to each other. Except for the above, the illumination device produced in the same manner as in Example 1 was used as Comparative Example 2, and the in-plane photon flux density at different distances from the light exit surface was measured in the same manner as in Example 1.

  The results are shown in Table 1 and FIG. In Table 1, the average value of the photon flux density at 36 points is indicated as “AVE”, the maximum value as “MAX”, and the minimum value as “MIN” (hereinafter the same). Further, FIG. 9 is a surface having a distance of 200 mm from the light emitting surface, and the photon flux density at points on two diagonals out of the 36 points shown in FIG. 8B is extracted and averaged from each end. It is a graph.

From these results, it can be seen that in the lighting device of Example 1, the photon density at the end is higher than that of Comparative Examples 1 and 2, and the uniformity is improved. In Example 1, it was confirmed that a photon density of 100 μmol / m ² / s or more required for plant growth could be secured even at a position 200 mm away from the lighting device.

<Examples 2 and 3>
The illumination devices of Examples 2 and 3 were manufactured in the same manner as in Example 1 except that the widths of the prism films adhered to the light guide plate were changed to 17.5 mm and 70 mm, respectively. For these manufacturing apparatuses, as in Example 1, the photon densities on four surfaces with different distances from the light emitting surface were measured. The results are shown in Table 2, FIG. 10 and FIG. FIG. 10 is a graph showing average illuminance at each distance in Examples 1 to 3, and FIG. 11 is a graph showing variation in illuminance distribution at each distance in Examples 1-3.

From these results, even when the width of the film is varied, the uniformity is improved as compared with Comparative Examples 1 and 2, and as shown in FIG. 10, even when the distance from the illumination device is 200 mm, 100 μmol / m ^2. It was confirmed that the amount of light above / s could be secured. As shown in FIG. 11, the variation coefficient of the illuminance distribution (light quantity distribution) tends to increase as the distance from the illumination device increases. In Example 1, the distance is long (200 mm). Also showed a relatively small value. In order to suppress the variation in plant growth, the smaller the variation coefficient, the better. Therefore, in Example 1, it was shown that the effect of suppressing the variation in growth was the highest in the early stage of plant growth.

  ADVANTAGE OF THE INVENTION According to this invention, the illuminating device which improved the in-plane uniformity of illumination intensity over the comparatively long distance range directly under the illuminating device can be provided. In addition, by using this lighting device as a lighting device for a plant growing device, it is possible to suppress variations in plant growth and increase the space utilization efficiency in both the horizontal direction and the vertical direction while ensuring the amount of light necessary for plant growing. Can do.

DESCRIPTION OF SYMBOLS 10 ... Illuminating device, 11 ... Housing | casing, 20 ... Light source part, 21 ... LED, 30 ... Light guide plate unit, 31 ... Light guide plate, 33 ... Reflective sheet, 35 ... Prism sheet, 50 ... plant, 70 ... plant growing device, 73 ... post, 75 ... shelf, 77 ... lighting device.

Claims (9)

A light guide plate having a light output surface and having four sides around the light output surface; and a light source that is disposed at at least one end of the light guide plate and receives light from a side surface of the light guide plate ;
A plant-growing illuminating device comprising a light control means for controlling light from the light guide plate in a direction orthogonal to the light output surface of the light guide plate along the four sides of the light output surface. . A plurality of illumination units each having a light output surface, a light guide plate having a plurality of sides around the light output surface, and a light source that is disposed at least at one end of the light guide plate and receives light from a side surface of the light guide plate pieces and the light emission surface a plant growing illumination device formed by placed on the surface direction of the light guide plate in the same direction,
The overall shape of the plurality of light exit surfaces constituted by the plurality of illumination units is a quadrangle having four sides around the overall shape,
Light control means for controlling the light from the light guide plate in a direction perpendicular to the light output surface of the light guide plate is disposed along a portion of the entire area of the square light output surface along the four sides . An illumination device for plant growth characterized by the above. The plant growing lighting device according to claim 1 or 2,
The plant growth lighting device, wherein the light control means is a prism sheet. The plant growing lighting device according to claim 3,
The plant-growing lighting device, wherein the prism sheet has a prism surface in which a plurality of triangular prisms are arranged in parallel, and is arranged on a light emitting surface so that the triangular prism is parallel to the edge. The plant growing lighting device according to claim 4,
The light exit surface has a polygonal shape, and at a corner where one side and an adjacent side intersect, a first prism sheet disposed along the one side and the adjacent side A plant growing lighting device, wherein the lighting device is arranged so as to intersect with a second prism sheet arranged along the line. A lighting device for plant cultivation according to any one of claims 1 to 5,
The plant growing lighting device, wherein the light source is an LED. A plant growing device comprising a frame including a plurality of support columns, a lighting device fixed to an upper portion of the frame, and a seedling shelf installed in a stock of the frame,
A plant growing device comprising the lighting device according to any one of claims 1 to 6 as the lighting device. A plant comprising a frame including a plurality of support posts, a plurality of seedling shelves arranged at intervals in the vertical direction within the frame, and a lighting device fixed to each upper part of the plurality of seedling shelves A training device,
A plant growing device comprising the lighting device according to any one of claims 1 to 6 as the lighting device.   The plant growing device according to claim 7 or 8, wherein the seedling shelf and the light emitting surface of the lighting device have substantially the same area.

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