JP2001086860A - Semiconductor light-emitting illuminating device for culturing plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor light-emitting illuminating device capable of performing a good quality plant culture by operating the light intensity ratio and delivered light distribution of its red and blue colors so as to become an optimal for a photosynthesis and photo shape formation of a plant. SOLUTION: This semiconductor light-emitting illuminating device is provided by being equipped with a red color LED 2 as a red colored light source necessary for a photosynthesis of a plant and a blue color LED 3 as a blue color light source necessary for a photo shape formation of the plant, making approximately as (8:1)-(12:1) relative light intensity ratio of the red color to the blue color by reducing the distribution number of the blue color-generating LED 3 than that of the red color-generating LED 2, and widening the delivered light distribution of the blue color LED 3 than that of the red color LED 2 for making the light intensity ratio of the red and blue lights per unit area of a soil as approximately uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor light emitting lighting system for plant cultivation using a semiconductor light emitting element which can be suitably used for growing plants in a plant factory or the like.

[0002]

2. Description of the Related Art In the field of cultivation of leafy vegetables such as leaf lettuce and other vegetables for prepared dishes and other plants, hydroponic cultivation uses artificial light without being influenced by seasons and weather. Fully controlled plant factories that can operate efficiently are rapidly spreading.

A high-pressure sodium lamp has been conventionally known as a light source for photosynthesis and photomorphogenesis used in a completely controlled plant factory. High pressure sodium lamp
Red (640-690n) important for photosynthesis and photomorphogenesis
m) and blue (420 to 470 nm) wavelength components, so that it was used as a light source for plant factories.

However, looking at the spectral distribution of a high-pressure sodium lamp, there are fewer blue components than red,
Although the efficiency of red photosynthesis of plants is high,
One of the drawbacks is that the blue is not sufficient in terms of photomorphogenesis of plants. And, because of the large amount of heat radiation accompanying the light emission, the air conditioning load on the cultivation booth of the plant factory increases, and the distance between the lamp and the cultivated plant needs to be increased to suppress the heat effect. Tends to be.

[0005] As described above, when the high-pressure sodium lamp is used as a light source, the blue light-emitting component is inferior in light intensity ratio to the red light-emitting component, which is not preferable in terms of healthy plant growth and cultivation efficiency. In addition, production costs are affected due to the inability to cope with downsizing of equipment and the air conditioning equipment and its operating costs.

Therefore, in order to solve the above problems, a semiconductor light emitting device using a semiconductor light emitting element (LED), which can be made much smaller than a high pressure sodium lamp and has no heat radiation, has been introduced. became. LE
The development of D has progressed rapidly in recent years, and a red light-emitting LED using a GaAlAs-based compound semiconductor has a center wavelength of about 660 nm. LED is 45
One having a center wavelength of about 0 nm is obtained. And since the spectrum of these red and blue emission wavelengths is almost the same as the peak of photosynthesis of a plant, it is optimal as a light source for plant cultivation. In addition, as described above, LEDs are small and emit little heat, so not only is a significant improvement in facilities expected, but also because pulse emission and low-voltage driving that greatly promote photosynthesis are possible. It is also possible to improve productivity and reduce costs.

[0007]

A light source for plant cultivation using such an LED has already been developed. For example, "Basic and actual plant factories" (by Masaki Takatsuji)
The basic principle is shown in FIGS. 4 and 9 on page 96 of Shokabo Publishing. This is a simple one in which a booth is set up on a cultivation tray containing cultivated soil, and a large number of red and blue light emitting LEDs are arranged on the ceiling of this booth. It has not been.

When such red and blue light emitting LEDs are arranged, the light intensity ratio between red light necessary for photosynthesis and blue light for forming light morphology may be about 10: 1. It is as described in. Therefore, if simply considered, the number of red light and blue light should just correspond to this light intensity ratio. In particular, if the light emission luminance of the red and blue LEDs is the same, the light intensity ratio should be close to 10: 1. Seems to be able to.

However, when the light intensity ratio is based on this concept, blue light emitting LEDs are scattered in a distribution in which the number of red LEDs is large. Such L
In the ED distribution, red light emission is distributed evenly to all the cultivated plants, but blue light emission is concentrated only on the portion near the LED, so that the cultivated plants at a distance are not sufficiently irradiated. Therefore, although there is no problem with photosynthesis of cultivated plants, photomorphogenesis due to blue light emission cannot be uniformed in all parts of the plant. As a result, the morphological quality of the cultivated plant varies, which reduces the added value of the product and greatly affects productivity.

As described above, when the red and blue LEDs are used as a light source for plant cultivation, the facility can be mainly improved, but the arrangement pattern of the red and blue LEDs is not appropriate, so that high-quality plant cultivation can be achieved. There is an obstacle in deployment.

[0011] The present invention provides a semiconductor light-emitting lighting system for plant cultivation that can cultivate high-quality plants by manipulating the light intensity ratio and light distribution of red and blue light so as to be optimal for photosynthesis and photomorphogenesis of plants. The purpose is to provide.

[0012]

According to the present invention, there is provided a semiconductor light emitting lighting system for cultivating a plant, which is disposed at a position facing a tray containing cultivated soil, and which promotes photosynthesis of a plant rooted in the cultivated soil. And a plurality of blue light-emitting diodes for promoting light morphology and a plurality of semiconductor light-emitting lighting equipment arranged on substantially the same plane, wherein the distribution number of the blue light-emitting diodes is smaller than the distribution number of the red light-emitting diodes. And, the light distribution of the blue light emitting diode is wider than the light distribution of the red light emitting diode, and the ratio of the light intensity of red and blue light per unit area of the soil is substantially uniform. I do.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 is arranged at a position facing a tray in which soil is put, and promotes photosynthesis of a plant rooted in the soil and red light-emitting diodes and light morphogenesis. A semiconductor light-emitting lighting apparatus in which a plurality of blue light-emitting diodes are arranged on a substantially same plane, wherein the number of distributions of the blue light-emitting diodes is smaller than the number of distributions of the red light-emitting diodes, and A semiconductor for plant cultivation, characterized in that the light distribution of the light emitting diode is wider than the light distribution of the red light emitting diode and the ratio of light intensity of red and blue is almost uniform per unit area of the soil. It is a luminous lighting facility, and has the effect that healthy growth of plants can be achieved by red and blue illumination light distribution that satisfies the conditions necessary for both photosynthesis and photomorphogenesis of plants.

According to a second aspect of the present invention, each of the red light emitting diode and the blue light emitting diode has a light distribution characteristic of a circle which distributes and diffuses light uniformly in all directions of the light source. The semiconductor light-emitting lighting equipment for plant cultivation according to claim 1, which has an effect that red and blue light-emitting diodes can be dealt with, for example, by a simple lattice-like pattern in which vertical and horizontal arrangement pitches are equal.

According to a third aspect of the present invention, the red light emitting diode has a light distribution distribution characteristic of a circle for uniformly distributing and diffusing light in all directions of the light emitting source, and the blue light emitting diode is substantially elliptical from the light emitting source. The semiconductor light-emitting lighting equipment for plant cultivation according to claim 1, wherein the light-distribution characteristics of an ellipse that disperses and diffuses light in a shape are parallel to each other. If the arrangement is such that the number of blue light emitting diodes per unit area of the soil can be reduced, it is possible to cope with such an arrangement.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic vertical sectional view of a plant cultivation apparatus provided with a semiconductor light emitting facility for plant cultivation according to the present invention.

As shown in FIG. 1, a plant cultivation apparatus includes a tray 51 containing soil and a booth 5 partitioning a space above the tray.
And a panel-shaped semiconductor light-emitting facility 1 provided on the ceiling of the booth 52. The semiconductor light emitting equipment 1 has a red LED 2 and a blue LED 3 on a flat base 1a.
FIG. 2A is a schematic side view of the arrangement of the LEDs 2 and 3 and the pattern of the light emission range, and FIG.
3 is a schematic plan view showing a planar array pattern and a light distribution.

As shown in FIG. 2A, red LEDs 2 and blue LEDs 3 are arranged at the same level in a plane substantially parallel to the surface of the soil 51a in the tray 51. Red LE
Each of the D2 and the blue LED 3 is a so-called shell type in which a semiconductor light emitting element is mounted and mounted on a lead frame and sealed with an epoxy resin package. In the example of FIG. 2, the cross section of the package is a circle, and the light distribution characteristic is a half-value of the half-value of the on-axis luminance. Is substantially a circle as shown in FIG.

The outline of the square shown in FIG. 2B has a side of 25 cm, which is 25 cm × 25 cm.
84 red LEDs 2 and 16 blue LEs in the area
D3 is arranged. For simplicity,
The red LED 2 is shown by a white circle and the blue LED 3 is shown by a black circle. These red and blue LEDs2,3
Is determined by the fact that the light intensity ratio per unit area suitable for plant cultivation is approximately 10: 1 for red and blue as described in the section of the prior art. And red LED
2 and the arrangement pattern of the blue LEDs 3 is, as is clear from FIG. 2B, the arrangement pitches in the vertical and horizontal directions are all equal, and a total of eight red LEDs 2 are arranged around the blue LED 3.
Is a surrounding relationship.

Here, the necessary conditions for satisfying both the photosynthesis and the light morphogenesis by the red LED 2 and the blue LED 3 are as follows. Distribution. Such an illumination distribution can be obtained by setting the respective light distribution characteristics of the red LED 2 and the blue LED 3. In other words, if the light distribution according to the light distribution characteristics of the red LED 2 is a small circle area range shown by a dotted line in FIG. 2B, the light distribution distribution areas of the red LEDs 2 vertically and horizontally adjacent to each other overlap. Then, the entire surface of the cultivation soil 51a has uniform illuminance. On the other hand, the number of the blue LEDs 3 is extremely smaller than that of the red LEDs 2 due to the relationship of the light intensity ratio.
For example, if the light distribution is a small circle like the red LED 2, a portion that does not reach the surface of the soil 51a is formed. On the other hand, the light distribution of the blue LED 3 is broadened and is shown in FIG.
In the case of, the entire surface of the cultivated soil 51a can be included in the irradiation area by making the area range of a large circle indicated by a solid line.

In the example shown in FIG. 2, the half-value light distribution angle of the red LED 2 is about 14 °, and the half-value light distribution angle of the blue LED 3 is about 21 °.

As described above, even if only a small number of blue LEDs 3 can be arranged in comparison with the red LEDs 2 to have a light intensity ratio necessary for photosynthesis and light morphology formation,
The plant can be irradiated with red and blue light at appropriate light intensity ratios by performing an operation of expanding the light distribution range from 3 to the light distribution range of the red LED 2. Therefore, photosynthesis and photomorphogenesis of the plant can be uniformly promoted, and high-quality plants can be cultivated.

FIG. 3 shows another embodiment of the semiconductor light emitting equipment according to the present invention, in which (a) is a schematic side view of an arrangement of red and blue LEDs 2 and 3 and a pattern of a light emitting range up to a half value of on-axis luminance. (B) is a schematic plan view of a light distribution showing a plane arrangement pattern of red and blue LEDs 2 and 3 and a locus of half-value of on-axis luminance. The surface area of the cultivated soil 51a in the tray 51 shown as a square outline in FIG. 3B has a size of 25 cm × 25 cm as in the previous example.

In this example, the red LED 2 has a circular light distribution area in all directions, as in the example of FIG. 2, and its light distribution half value angle is about 14 °. The blue LED 3 has an elliptical light distribution. FIG. 4 shows the shape of the package and FIG. 5 shows the light distribution characteristics in the major axis direction and the minor axis direction.

As shown in FIG. 4, in the blue LED 3, a light emitting element (not shown) is conductively mounted at the tip of a forked lead frame 3a, and this light emitting element is resin-sealed by a shell type package 3b made of epoxy resin. Things. The tip of the package 3b is formed in a spherical shape, and has a substantially elliptical cross-sectional shape as shown in FIG. Due to such an elliptical cross-sectional shape of the package 3b, the light distribution characteristics in the major axis direction and the minor axis direction of the elliptical cross section are patterns shown in FIGS. 5A and 5B, respectively. 5A and 5B, the horizontal axis represents the angle of the resin lens of the package 3b from the optical axis, and the vertical axis represents the relative luminous intensity (%) with respect to the luminous intensity on the optical axis. . As can be seen from the characteristic diagram of the light distribution, the relative light emission intensity is 50% or more in the range of about 37 ° with respect to the optical axis in the long axis direction, and the light distribution is more effective in the short axis direction than in the long axis direction. The distribution angle is small. Therefore, package 3
The light distribution from b has a relationship substantially similar to the ellipse of the cross-sectional shape.

In the example shown in FIG. 3, the half-value light distribution angle of the red LED 2 is about 14 ° as described above, and the blue LE
D3 has a light distribution angle of about 14 ° in the short axis direction and about 37 ° in the long axis direction. This light distribution angle is an angle of 0 ° (package 3 in the light distribution characteristic diagram shown in FIG. 5).
(corresponds to the optical axis of b) in the minor axis and major axis directions. If the light distribution angle in the major axis direction is 37 °, the relative luminous intensity (%) in that angle range is 50 or more. Indicates that

As shown in FIG. 3B, the number of arrays of the blue LEDs 3 in the package 3b having an elliptical cross section is smaller than that of the previous example, and the blue LED 3 has a square area obtained by dividing a 25 cm × 25 cm area into four parts. Two or three are respectively included. The blue LEDs 3 arranged in two rows in the vertical direction on the left and right are vertically shifted by one pitch of the grid-like arrangement pitch including the red LEDs 2. With such an array pattern of the blue LEDs 3, an elliptical light distribution as shown in the figure is obtained, and almost the entire area of 25 cm × 25 cm can be illuminated with a relative light emission intensity of 50% or more.

On the other hand, in the arrangement pattern of the red LEDs 2, as in the example of FIG. Is to be obtained.

Even when the blue LED 3 forms an elliptical light distribution, red by the red LED 2 required for photosynthesis and blue by the blue LED 3 required for light morphology formation are cultivated 51a.
Can be uniformly irradiated on all surfaces. The number of the blue LEDs 3 is smaller than that of the example of FIG. 2, and the setting of the light intensity ratio of red and blue necessary for photosynthesis and light morphology can be further optimized. Therefore, at present, the cost of a blue light emitting LED using a GaN-based compound semiconductor is high, but it is also possible to reduce the equipment cost by reducing the required number.

[0031]

According to the present invention, the light intensity ratio of red and blue luminescence necessary for photosynthesis and photomorphogenesis of plants is 8: 1 to 12: 1.
In order to satisfy the condition of preferably about 10: 1, the number of blue light emitting diodes per unit area of the soil must be smaller than that of red, but the light distribution of the blue light emitting diodes is wider than that of red. As a result, the light intensity ratio between red and blue can be made uniform, an illumination mode that sufficiently satisfies the above conditions can be obtained, and high-quality plants can be cultivated.

Further, since the light emitting diode can perform pulsed light emission and low voltage driving and generate little heat, the light emission can further promote photosynthesis by the pulsed light emission, and the light source can be arranged close to the plant, so that the size of the device can be reduced. In addition, the cost for equipment and operation including air conditioning can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a plant cultivation apparatus provided with a semiconductor light emitting facility for plant cultivation of the present invention.

2A is a schematic side view of an arrangement of red and blue light emitting LEDs and a pattern of a light emitting range. FIG. 2B is a schematic plan view showing a planar array pattern and light distribution of red and blue light emitting LEDs.

FIG. 3 is an example in which a blue LED has an elliptical light distribution,
(A) is a schematic side view of an arrangement of red and blue light emitting LEDs and a pattern of a light emitting range up to half the on-axis luminance half value. (B) shows a planar arrangement pattern of red and blue light emitting LEDs and a locus of an on-axis semicircle. Schematic plan view of light distribution

4 (a) is a front view of a lead frame and a package part, and FIG. 4 (b) is a right side view of FIG. 3 (a). ) Is a plan view of the package

5A and 5B are light distribution characteristics diagrams of the blue light emitting LED of FIG. 4, wherein FIG. 5A is a characteristic diagram of a relative light emission intensity in a major axis direction of an elliptical cross-section package, and FIG. Characteristic diagram of relative emission intensity in each direction

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor light emitting equipment 2 Red LED 3 Blue LED 3a Lead frame 3b Package 51 Tray 51a Cultivation 52 Booth

Claims (3)

[Claims] 1. A red light-emitting diode for promoting photosynthesis of a plant rooted in the soil and a blue light-emitting diode for promoting light morphogenesis, which are arranged at a position facing the tray containing the soil and are substantially coplanar with each other. A plurality of semiconductor light-emitting lighting equipment, wherein the number of distributions of the blue light-emitting diodes is smaller than the number of distributions of the red light-emitting diodes, and the light distribution of the blue light-emitting diodes is changed to the red light emission. A semiconductor light emitting lighting system for plant cultivation, characterized in that the light distribution is wider than the light distribution of the diode and the ratio of light intensity of red and blue is almost uniform per unit area of the soil. 2. The light-emitting diode according to claim 1, wherein each of the red light-emitting diode and the blue light-emitting diode has a light distribution characteristic of a circle that distributes and diffuses light uniformly in all directions of the light-emitting source. Semiconductor lighting equipment for plant cultivation. 3. An ellipse, wherein the red light emitting diode has a light distribution characteristic of a circle for uniformly distributing and diffusing light in all directions of the light emitting source, and the blue light emitting diode is substantially elliptical from the light emitting source for light distribution and diffusion. The semiconductor light-emitting lighting equipment for plant cultivation according to claim 1, wherein the light distribution characteristics are as follows.