WO2019211956A1

WO2019211956A1 - Led illuminating device for plant cultivation and method for illuminating said led

Info

Publication number: WO2019211956A1
Application number: PCT/JP2019/012866
Authority: WO
Inventors: 裕司大畠
Original assignee: 株式会社芝川製作所
Priority date: 2018-05-01
Filing date: 2019-03-26
Publication date: 2019-11-07
Also published as: JP2021119743A

Abstract

Provided is an LED illumination technology for plant cultivation, said technology allowing easy optimization of an emission spectrum in order to efficiently enhance the growth effect. An LED illuminating device (10) is provided with: white LEDs (11) having an emission spectrum in which the wavelength range is continuous from at least 450 nm to 700 nm; monochrome LEDs (12) having at least one peak in the emission spectrum; and a circuit board on which the plurality of white LEDs (11) are arranged, and the monochrome LEDs (12) are uniformly arranged in the group of white LEDs (11).

Description

LED lighting device for plant cultivation and LED lighting method thereof

The present invention relates to an illumination technique for plant cultivation having an LED (light emitting diode) as a light source.

In a lighting device installed in a plant factory, it has been studied to replace a light source with an LED from a fluorescent lamp which has been mainstream until now. The reason is that if the LED is replaced, the disadvantage of the fluorescent lamp, that is, the large power consumption and heat generation, is eliminated, and the lifetime is short, and the production cost in the plant factory can be expected to be improved.

Commercialization of LED lighting devices for plant cultivation began with the combination of two types of light sources, a blue LED that emits monochromatic light near a wavelength of 450 nm and a red LED that emits monochromatic light near a wavelength of 620 nm. After that, a light source having a white LED that emits light in a continuous wavelength range from 400 nm to 700 nm was introduced. At the time of filing, white LEDs that have a lower color temperature than conventional white LEDs, emit light with high color rendering, and emit light in a continuous broadband from wavelengths of 400 nm to 780 nm are attracting attention as light sources for plant cultivation. .

JP 2016-202072 A Japanese Unexamined Patent Publication No. 2016-007185

As a result of adopting fluorescent lamps as a light source for a long time, the results of cultivated plants by plant factories have reached a certain level of satisfaction. However, as a result of replacing the light source with the LED, there have been reported cases in which the degree of satisfaction is reduced with respect to the result of the cultivated plant.

Specifically, in the cultivation of leafy vegetables such as lettuce, although LED light sources have achieved practical results, they have been evaluated as inferior to the results of fluorescent light sources. Further, in the cultivation of fruit and vegetables such as strawberries and tomatoes, satisfactory results have not been obtained with LED light sources with regard to coloring of fruits that are not pointed out with fluorescent light sources.

As a reason for this, when comparing the emission spectrum of the light source, the R / B ratio (red / blue ratio) and the R / FR ratio (red / far red ratio) are greatly different between the LED and the fluorescent lamp. It is mentioned. For this reason, if the R / B ratio and R / FR ratio of a light source are optimized, it can be expected to further improve the cultivation and cultivation effect of plants.

By the way, if the light source is composed of only white LEDs and the emission spectrum is to be optimized, a phosphor that easily deteriorates is used, and the optimized emission spectrum may change inappropriately over time. It becomes a problem. In addition, white LEDs with low color temperature and high color rendering, which are increasing in demand as light sources for plant cultivation, also have a problem that light emission efficiency is low as compared with white LEDs and single color LEDs for general illumination.

The present invention has been made in consideration of such circumstances, and provides an LED lighting technique for plant cultivation that can easily optimize the emission spectrum in order to efficiently improve the growth effect. Objective.

In the LED illuminating device for plant cultivation according to the present invention, a white LED having an emission spectrum having a wavelength range of at least 450 nm to 700 nm, a monochromatic LED having at least one peak in the emission spectrum, and a plurality of the white LEDs. And a circuit board on which the monochromatic LEDs are uniformly arranged in the group of white LEDs.

The present invention provides an LED illumination technique for plant cultivation that can easily optimize the emission spectrum in order to improve the growth effect efficiently.

(A) Whole circuit diagram which shows LED illuminating device for plant cultivation concerning 1st Embodiment of this invention, (B) The partial circuit diagram which shows LED illuminating device of another example. (A) The graph which overlaid the single emission spectrum of white LED and red LED applied to the LED illuminating device for plant cultivation which concerns on 2nd Embodiment, (B) The emission spectrum of white LED and red LED is synthesize | combined. Chart. (A) The graph which overlaid the single light emission spectrum of white LED, red LED, and far-red LED applied to the LED lighting apparatus for plant cultivation which concerns on 3rd Embodiment, (B) White LED, red LED, and The graph which synthesize | combined the emission spectrum of far-red LED. (A) The graph which overlaid the emission spectrum of the single unit of white LED and ultraviolet LED applied to the LED lighting apparatus for plant cultivation concerning 4th Embodiment, (B) The synthesis | combination of the emission spectrum of white LED and ultraviolet LED Chart. (A) The graph which overlaid the single light emission spectrum of white LED, red LED, and ultraviolet LED applied to the LED lighting apparatus for plant cultivation which concerns on 5th Embodiment, (B) White LED, red LED, and ultraviolet-ray The graph which synthesize | combined the emission spectrum of LED. (A) A graph in which a single LED emission spectrum of white LED, red LED, far-red LED and ultraviolet LED is applied to the LED lighting device for plant cultivation according to the sixth embodiment, (B) white LED, The graph which synthesize | combined the emission spectrum of red LED, far-red LED, and ultraviolet LED. The table which shows the effect of the LED lighting method for plant cultivation concerning each embodiment.

(First embodiment)
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1A is a circuit diagram showing an LED illumination device 10A for plant cultivation according to the first embodiment of the present invention, and FIG. 1B is a partial circuit diagram showing an LED illumination device 10B of another example. is there.

As shown in FIG. 1A, an LED illumination device 10A includes a white LED 11 having a continuous emission spectrum in a wavelength range of at least 450 nm to 700 nm, a monochromatic LED 12 having at least one peak in the emission spectrum, and a plurality of white LEDs. And a circuit board (not shown) on which the monochromatic LEDs 12 are uniformly arranged in the group of the white LEDs 11.

The white LED 11 is for general illumination with excellent luminous efficiency. As described above, for the purpose of improving the growth effect, the white LED for plant cultivation that emits light with higher color rendering than the white LED for general illumination (color rendering value Ra = 90, color temperature around 3000K) ) Is commercially available. However, this white LED for plant cultivation does not need to be positively adopted because the light emission efficiency of the chip is poor and the amount of light is small.

Examples of the single color LED 12 include a red LED 12a, a far red LED 12b, and an ultraviolet LED 12c described later, but are not particularly limited. These single color LEDs 12 may be arranged in one type or may be arranged in combination of two or more types.

As shown in FIG. 1 (B), in the LED lighting device 10B, a switch 16 for individually turning on / off energization of at least one single-color LED 12 is provided on a circuit board (not shown).

In the LED illumination device 10B of FIG. 1B, the white LED 11 and the single color LED 12 are connected in series with each other and connected to the constant current circuit 15a. In the LED lighting device 10A of FIG. 1A, a group of white LEDs 11 and single color LEDs 12 connected in series with each other is further connected in parallel (three rows in the figure) and connected to the constant current circuit 15a. Has been.

Here, the arrangement of the white LED 11 and the single color LED 12 in the LED lighting device 10 is arranged so that one of them is not unevenly distributed as a whole so that each light emission is uniformly mixed with the irradiation surface. In the illustration of FIG. 1 (A), one single-color LED 12 is regularly arranged every two white LEDs 11, but it is not particularly necessary to have regularity in this arrangement. In FIG. 1A, each of the three exemplified columns has the same arrangement, but may have a different arrangement.

The LED lighting device 10 is structurally compatible with a conventional straight tube fluorescent lamp by accommodating a circuit board on which a white LED 11 and a single color LED 12 are mounted in a transparent cylinder and aligning the base shape and length. be able to. The LED lighting device 10 is structurally compatible with a conventional incandescent bulb by accommodating a circuit board on which a white LED 11 and a single color LED 12 are mounted in a transparent hemisphere and aligning the base shape and size. Can be given. In order to provide compatibility with an incandescent bulb, the white LED 11 and the single color LED 12 are arranged in a planar shape on a circular circuit board.

As shown in FIG. 1B, when the switch 16 is connected in parallel to the single color LED 12 to be energized, the single color LED 12 is lit when the switch 16 is open, and the single color LED is closed. The LED 12 is turned off.

Note that the switch 16 does not have to be provided for all the single color LEDs 12, and may be provided according to the adjustment amount of the monochromatic light to be combined with the light emission of the white LED 11. Further, the switch 16 specifically short-circuits or conducts each other by inserting or removing a conductor from a printed pattern of wiring that is not electrically connected on a circuit board (not shown). This is realized with a jumper or the like. Alternatively, the switch 16 may be a mechanical type that performs ON / OFF reversibly.

In this way, by configuring the LED lighting device 10 with the white LED 11 and the single color LED 12, adjusting the arrangement number ratio thereof, the R / B ratio (red / blue ratio) and R / FR ratio of the emission spectrum ( Red / far red ratio) and the like can be optimized, and the cultivation and cultivation effect of the plant can be improved.

Further, by providing the switch 16, the number of monochromatic LEDs 12 to be lit can be easily changed without changing the wiring pattern of a circuit board (not shown), and the R / B ratio and R / B of the emission spectrum can be changed. The FR ratio and the like can be optimized. This means that if the optimum conditions such as the R / B ratio and R / FR ratio differ depending on the type of plant and the stage of cultivation, the optimum conditions can be set only by setting the switch 16 without significantly changing the design specifications of the product. Can be set. Alternatively, the emission spectrum distribution can be easily changed even in an experiment for searching for the optimum condition of the cultivated plant.

The LED illumination method for plant cultivation according to the first embodiment is not limited to using the LED illumination device 10 described above. That is, monochromatic LEDs are uniformly arranged in a group of white LEDs arranged in plural, and the white LED emits a continuous emission spectrum having a wavelength range of at least 450 nm to 700 nm, and at least one peak is emitted from the monochromatic LED. By emitting in the emission spectrum.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 2 (A) is a graph in which single emission spectra of the white LED 11 and the red LED 12a (monochromatic LED 12) applied to the plant lighting LED illumination device 10 according to the second embodiment are overwritten, and FIG. B) is a graph in which the emission spectra of the white LED 11 and the red LED 12a are synthesized. 2 that are related to FIG. 1 are denoted by the same reference numerals, and redundant description is omitted.

For the circuit board of the LED lighting device 10 according to the second embodiment, a chip having a color rendering value Ra of approximately 80 for general illumination and a color temperature of 5000 K is selected as the white LED 11, and the single color LED 12 is centered in the wavelength range of 600 nm to 700 nm. The chip of the red LED 12a having a peak with a wavelength of 660 nm is selected.

In the synthetic emission spectrum shown in FIG. 2B, the peak top derived from the red LED 12a existing in the red wavelength range of 600 nm to 700 nm, and the peak top derived from the white LED 11 existing in the blue wavelength range of 415 nm to 500 nm The number of lighting of the red LED 12a is adjusted so that the R / B ratio of.

7 shows the effect of the LED lighting method for plant cultivation according to the second embodiment in the column of Example 2 of the table of FIG. As Comparative Example 1, a 40-type fluorescent lamp was used, and the cultivation evaluation performed on lettuce, tomato seedlings, and strawberries was represented by a reference value of 100 points.

In addition, lettuce was performed with leaf lettuce, tomato was performed with self-rooted tomato seedlings, and growth judgment materials were comprehensively judged with a sense of volume, stock width, leaf size, color, and the like. The leaf lettuce was determined 20 days after planting, and the tomato seedlings were determined 19 days after sowing. In addition, for 6 strawberries “Tochiotome”, the growth judgment materials were comprehensively judged on petiole length, number of fruits, fruit weight, etc., and judged in the first month after planting.

As a result, the evaluation of the second embodiment (Example 2) was 120 points for lettuce, 40 points for tomato, and 120 points for strawberry. In Example 2, the peak top R / B ratio was 2.5. However, the peak top R / B ratio is not limited to this value, and the peak top R / B ratio is 2.0 to 3.0. It is desirable to be included in the range. In the Example which remove | excluded this range, compared with the comparative example which uses a fluorescent lamp, the growth effect of the plant outstanding was not implement | achieved.

In addition, the specification of the emission spectrum with which the excellent plant-growing effect can be obtained can be defined by the ratio of the integral value of the wavelength range of the emission spectrum. Specifically, the R / B ratio between the integrated value in the red wavelength range of 600 nm to 700 nm and the integrated value in the blue wavelength range of 415 nm to 500 nm may be specified in the range of 1.6 to 4.3. Further, the R / G ratio between the integrated value in the red wavelength range of 600 nm to 700 nm and the integrated value in the green wavelength range of 500 nm to 600 nm may be specified in the range of 1.2 to 2.5.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 3 (A) was overwritten with a single emission spectrum of white LED 11, red LED 12a (single color LED 12) and far red LED 12b (single color LED 12) applied to the LED lighting device for plant cultivation according to the third embodiment. FIG. 3B is a graph in which emission spectra of the white LED 11, the red LED 12a, and the far red LED 12b are synthesized. In FIG. 3, the same reference numerals are used to refer to those in FIG. 1 and FIG.

The circuit board of the LED lighting device 10 according to the third embodiment includes a white LED 11, a red LED 12a as the single color LED 12, and a far red LED 12b having a peak with a center wavelength of 735 nm in the wavelength range of 700 nm to 800 nm as the single color LED 12. Is arranged.

In the synthetic emission spectrum shown in FIG. 3 (B), the R / B ratio (= 2.5) maintains the state of FIG. 2 (B), while the peak top derived from the

red LED

12a and 700 nm to 800 nm. The number of lighting of the far red LED 12b is adjusted so that the R / FR ratio with the peak top derived from the far red LED 12b existing in the far red wavelength range approaches 5.

7 shows the effect of the LED lighting method for plant cultivation according to the third embodiment in the column of Example 3 in the table of FIG. As a result, evaluation of 3rd Embodiment (Example 3) was 150 points for lettuce, 50 points for tomatoes, and 130 points for strawberries.

In Example 3, the peak top R / FR ratio was 5. However, the peak top R / FR ratio is in the range of 4.0 to 6.0 without being limited to this value. It is desirable to be included in. In the Example which remove | excluded this range, compared with the comparative example which uses a fluorescent lamp, the growth effect of the plant outstanding was not implement | achieved.

In addition, the specification of the emission spectrum with which the excellent plant-growing effect can be obtained can be defined by the ratio of the integral value of the wavelength range of the emission spectrum. Specifically, the R / FR ratio between the integrated value in the red wavelength range of 600 nm to 700 nm and the integrated value in the far red wavelength range of 700 nm to 800 nm may be specified in the range of 2.6 to 7.3.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIGS. FIG. 4 (A) is a graph in which the single light emission spectra of the white LED 11 and the ultraviolet LED 12c (monochromatic LED 12) applied to the plant lighting LED illumination device 10 according to the fourth embodiment are overwritten, and FIG. B) is a graph in which the emission spectra of the white LED 11 and the ultraviolet LED 12c are synthesized. 4 that are related to FIGS. 1 to 3 are denoted by the same reference numerals, and redundant description is omitted.

On the circuit board of the LED lighting device 10 according to the fourth embodiment, a white LED 11 and an ultraviolet LED 12c having a peak with a central wavelength of 395 nm in a wavelength range of 350 nm to 425 nm as a monochromatic LED 12 are arranged.

In the synthetic emission spectrum shown in FIG. 4B, the UVA / peak of the peak top derived from the ultraviolet LED 12c in the ultraviolet wavelength range of 350 nm to 425 nm and the peak top derived from the white LED 11 existing in the blue wavelength range of 415 nm to 500 nm. The lighting number of the ultraviolet LED 12c is adjusted so that the B ratio approaches 1.

7 shows the effect of the LED lighting method for plant cultivation according to the fourth embodiment in the column of Example 4 in the table of FIG. As a result, evaluation of 4th Embodiment (Example 4) was 100 points for lettuce, 100 points for tomato seedlings, and 150 points for strawberries.

In Example 4, the peak top UVA / B ratio is 1 but is not limited to this value. The peak top UVA / B ratio is in the range of 0.5 to 1.5. It is desirable to be included in. In the Example which remove | excluded this range, compared with the comparative example which uses a fluorescent lamp, the growth effect of the plant outstanding was not implement | achieved.

In addition, the specification of the emission spectrum with which the excellent plant-growing effect can be obtained can be defined by the ratio of the integral value of the wavelength range of the emission spectrum. Specifically, the UVA / B ratio between the integrated value in the ultraviolet wavelength range of 350 nm to 425 nm and the integrated value in the far red wavelength range of 415 nm to 500 nm may be specified in the range of 0.5 to 1.5.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described with reference to FIGS. FIG. 5 (A) was overwritten with a single emission spectrum of white LED 11, red LED 12a (single color LED 12) and ultraviolet LED 12c (single color LED 12) applied to the LED lighting device 10 for plant cultivation according to the fifth embodiment. FIG. 5B is a graph in which the emission spectra of the white LED 11, the red LED 12a, and the ultraviolet LED 12c are synthesized. 5 that are related to FIGS. 1 to 4 are denoted by the same reference numerals, and redundant description is omitted.

The white LED 11 and the red LED 12a and the ultraviolet LED 12c as the single color LED 12 are arranged on the circuit board of the LED lighting device 10 according to the fifth embodiment.

In the synthetic emission spectrum shown in FIG. 5B, the R / B ratio (= 2.5) is the same as in FIG. 2B, and the UVA / B ratio (= 1) is the same as that in FIG. The number of lighting of the red LED 12a and the ultraviolet LED 12c is adjusted so as to be in the same state.

7 shows the effect of the LED lighting method for plant cultivation according to the fifth embodiment in the column of Example 5 of the table of FIG. As a result, evaluation of 5th Embodiment (Example 5) was lettuce 120 points, a tomato seedling 110 points, and a strawberry 170 points.

In Example 5, the peak top R / B ratio was 2.5 and the UVA / B ratio was 1. However, the present invention is not limited to this value. It is desirable to be included in the range. In the Example which remove | excluded this range, compared with the comparative example which uses a fluorescent lamp, the growth effect of the plant outstanding was not implement | achieved. In addition, as described above, the specification of the emission spectrum that provides an excellent plant-growing effect can be defined by the ratio of the integrated value in the wavelength range of the emission spectrum.

(Sixth embodiment)
Next, a sixth embodiment of the present invention will be described with reference to FIGS. FIG. 6A shows a white LED 11, a red LED 12a (single color LED 12), a far red LED 12b (single color LED 12), and an ultraviolet LED 12c (single color LED 12) applied to the LED lighting device 10 for plant cultivation according to the sixth embodiment. FIG. 6B is a graph obtained by combining the emission spectra of the white LED 11, the red LED 12a, the far red LED 12b, and the ultraviolet LED 12c. 6 that are related to FIGS. 1 to 5 are denoted by the same reference numerals, and redundant description is omitted.

On the circuit board of the LED lighting device 10 according to the sixth embodiment, a white LED 11 and a red LED 12a, a far red LED 12b, and an ultraviolet LED 12c as a single color LED 12 are arranged.

In the synthetic emission spectrum shown in FIG. 6B, the R / B ratio (= 2.5) is the same as in FIG. 2B, and the R / FR ratio (= 5) is the same as FIG. 3B. The number of lighting of the red LED 12a, the far red LED 12b, and the ultraviolet LED 12c is adjusted so that the same state and the UVA / B ratio (= 1) are the same as those in FIG. 4B.

7 shows the effect of the LED lighting method for plant cultivation according to the sixth embodiment in the column of Example 6 of the table of FIG. As a result, the evaluation of the sixth embodiment (Example 6) was 150 points for lettuce, 130 points for tomato seedlings, and 200 points for strawberries.

In Example 6, the peak top R / B ratio was 2.5, the R / FR ratio was 5, and the UVA / B ratio was 1. However, the present invention is not limited to this value. Each ratio is preferably included in the above-described range. In the Example which remove | excluded this range, compared with the comparative example which uses a fluorescent lamp, the growth effect of the plant outstanding was not implement | achieved. In addition, as described above, the specification of the emission spectrum that provides an excellent plant-growing effect can be defined by the ratio of the integrated value in the wavelength range of the emission spectrum.

As described above, the effectiveness of the effect on leaf vegetables such as lettuce and fruit vegetables such as tomato and strawberry was confirmed using the LED lighting device for plant cultivation according to each embodiment. In addition, the effectiveness of the effect for electric cultivation such as chrysanthemums, perillas, and rhododendrons has been confirmed.

10 (10A, 10B) ... LED lighting device, 11 ... white LED, 12 ... single color LED, 12a ... red LED, 12b ... far red LED, 12c ... ultraviolet LED, 15a ... constant current circuit, 16 ... switch.

Claims

A white LED having an emission spectrum having a wavelength range of at least 450 nm to 700 nm, and
A monochromatic LED having at least one peak in the emission spectrum;
An LED lighting device for plant cultivation, comprising: a plurality of white LEDs, and a circuit board that uniformly arranges the monochromatic LEDs in the group of white LEDs.
In the LED lighting device for plant cultivation according to claim 1,
The LED lighting device for plant cultivation, wherein the monochromatic LED is a red LED having the peak in a wavelength range of 600 nm to 700 nm.
In the LED lighting device for plant cultivation according to claim 2,
An LED lighting apparatus for plant cultivation, wherein the monochromatic LED is further provided with a far-red LED having the peak in a wavelength range of 700 nm to 800 nm.
In the LED lighting device for plant cultivation according to claim 1,
The LED lighting apparatus for plant cultivation, wherein the monochromatic LED is an ultraviolet LED having the peak in a wavelength range of 350 nm to 425 nm.
In the LED lighting device for plant cultivation according to claim 2,
An LED lighting device for plant cultivation, wherein the monochromatic LED is further provided with an ultraviolet LED having the peak in a wavelength range of 350 nm to 425 nm.
In the LED lighting device for plant cultivation according to claim 3,
An LED lighting device for plant cultivation, wherein the monochromatic LED is further provided with an ultraviolet LED having the peak in a wavelength range of 350 nm to 425 nm.
In the LED lighting device for plant cultivation according to any one of claims 1 to 6,
An LED lighting device for plant cultivation, wherein the circuit board is provided with a switch for individually turning on / off energization of at least one of the monochromatic LEDs.
In the LED lighting device for plant cultivation according to any one of claims 2, 3, 5, and 6,
The wavelength range of 600 nm to 700 nm and the wavelength range of 415 nm to 500 nm obtained by synthesizing the emission spectra of the white LED and the monochromatic LED are as follows:
Whether the R / B ratio of each peak top is included in the range of 2.0 to 3.0,
Alternatively, the R / B ratio of the integrated value is included in the range of 1.6 to 4.3, and the R / G ratio of the integrated value is included in the range of 1.2 to 2.5. LED lighting device.
In the LED lighting device for plant cultivation according to claim 3 or claim 6,
The wavelength range of 600 nm to 700 nm and the wavelength range of 700 nm to 800 nm obtained by synthesizing the emission spectra of the white LED and the monochromatic LED are as follows:
The R / FR ratio of each peak top is included in the range of 4.0 to 6.0,
Alternatively, the LED lighting device for plant cultivation, wherein the integrated value R / FR ratio is included in the range of 2.6 to 7.3.
In the LED lighting device for plant cultivation according to claim 4 or claim 6,
The wavelength range of 350 nm to 425 nm and the wavelength range of 415 nm to 500 nm, in which the emission spectra of the white LED and the monochromatic LED are synthesized,
Whether the UVA / B ratio of each peak top is in the range of 0.5 to 1.5,
Alternatively, the LED lighting device for plant cultivation, wherein the integrated value UVA / B ratio is included in the range of 0.5 to 1.5.
Emitting a white LED having an emission spectrum having a continuous wavelength range from at least 450 nm to 700 nm;
Emitting a monochromatic LED having at least one peak in the emission spectrum,
An LED illumination method for plant cultivation, wherein the single color LEDs are uniformly arranged in a group of the white LEDs in which a plurality are arranged.