JP6974740B2 - Light emitting device, lighting device and plant cultivation method - Google Patents

Description

The present invention relates to a light emitting device, a lighting device and a plant cultivation method.

In the midst of environmental changes caused by climate change and human-made environmental destruction, it is desired to stably supply plants such as vegetables and improve the production efficiency of plants. For example, a plant factory that can be artificially managed is expected as a next-generation industry because it can stably supply clean and safe vegetables to the market. In a plant factory, a light emitting device using a light emitting diode (hereinafter referred to as "LED") is adopted in order to reduce power consumption and grow plants efficiently.

The reaction of plants to light is divided into photosynthesis and photomorphogenesis, and photosynthesis is a reaction that uses light energy to synthesize organic substances. Photomorphogenesis is a morphological reaction that uses light as a signal to perform seed germination, differentiation (germination formation, leaf formation, etc.), movement (stomata opening / closing, chloroplast movement), phototropism, etc. It is a reaction. There are multiple photoreceptors (pigments) in plants, and chlorophyll and carotenoids photosynthesize.

For example, Patent Document 1 discloses a light emitting device that combines a red LED having an emission peak wavelength in the wavelength range of 630 nm to 680 nm and two LEDs having different emission peak wavelengths in the wavelength range of 380 nm to 480 nm. Has been done. Further, a blue LED chip that generates light having an emission peak wavelength within the wavelength range of 400 nm to 480 nm corresponding to the blue region absorption peak of chlorophyll and a red region absorption peak of chlorophyll that absorbs the light of this blue LED chip. Disclosed is a light emitting device in which a red phosphor that emits light having a emission peak wavelength in the wavelength range of 620 nm to 700 nm corresponding to the above is combined.

In plants, in addition to chlorophyll and carotenoids, as photoreceptors (pigments), phytochrome, which is a photoreceptor for red light and far-red light, blue light, and crypto, which is a photoreceptor for near-ultraviolet light (UV-A). Chromium and phototropin are present. For example, phytochrome absorbs red and far-red light and promotes photomorphogenesis of plants such as induction of seed germination, cotyledon development, stem elongation, and phototropism.

Plants use photoreceptors to sense the light environment and undergo photosynthetic and photomorphogenic reactions. The wavelength range (300 nm or more and 800 nm or less) that plants can use for photosynthesis and photomorphogenesis is almost the same as the wavelength range of visible light (380 nm or more and 780 nm or less). In the field of plants, radiation in the wavelength range that can be used for photosynthetically active reactions and photomorphogenic reactions is called Physiologically Active Radiation, and among them, wavelengths of 400 nm or more and 700 nm or less, which are energy sources for plant growth. Radiation in the region is called Photosynthetically Active Radiation. Further, in the field of plants, the wavelength range generally includes a wavelength range of about 400 nm to about 500 nm, for example B, a wavelength range of about 500 nm to about 600 nm, for example G, and a wavelength range of about 600 nm to about 700 nm, for example R, about 700 nm. The wavelength range from about 800 nm may be represented by, for example, Fr. Further, an index of the amount of light effective for photosynthesis and photomorphogenesis of a plant is expressed not by a radiant flux but by a photon flux or a photon flux density. The spectral distribution of the light source that affects the growth of plants, for example, will be described in detail later, but depends on the ratio R / B or ratio R / Fr of the photon flux in another specific wavelength region to the photon flux in a specific wavelength region. .. For example, Non-Patent Document 1 discloses that, as shown in FIG. 11, the difference in the spectral distribution of the light source affects, for example, the plant height of romaine lettuce, and the smaller the R / Fr, the higher the plant height of romaine lettuce. There is.

International Publication No. 2012/070435

Hanana Shirai et al., Plant growing effect of white LEDs with different spectral distributions, Proceedings of the 2016 Kanazawa Convention of the Japanese Society of Agricultural Engineering, Japan, p. 40, 41

As disclosed in Patent Document 1, together with a light source that irradiates an emission peak wavelength that is easily absorbed by chlorophyll involved in the photosynthetic reaction, an emission peak that is easily absorbed by photoreceivers other than chlorophyll as the plant grows. If the wavelength can be irradiated, the photomorphogenesis of plants can be promoted.
Therefore, one aspect of the present invention is to provide a light emitting device, a lighting device, and a plant cultivation method capable of promoting the growth of plants.

The present invention includes the following aspects.
The first aspect of the present invention is a light emitting device having a emission peak wavelength in the wavelength range of 380 nm or more and 490 nm or less.
A first phosphor that is excited by light from the light emitting device and emits light having at least one emission peak wavelength within a wavelength range of 580 nm or more and less than 680 nm.
A second phosphor that is excited by light from the light emitting element and emits light having at least one emission peak wavelength within a wavelength range of 680 nm or more and 800 nm or less is provided.
The ratio R / B of the photon bundle R of red light in the wavelength range of 620 nm or more and less than 700 nm to the photon bundle B of blue light in the wavelength range of 400 nm or more and 490 nm is more than 4 and 50 or less.
The ratio R / Fr of the photon bundle R to the photon bundle Fr of far-red light in the wavelength range of 700 nm or more and 780 nm or less is 0.1 or more and 10 or less.
The second element Ln contains at least one element selected from the group consisting of Al, a first phosphorate phosphor having a composition containing Cr, and a rare earth element excluding Ce. It has a composition containing Al, a second element M containing at least one element selected from the group consisting of Ga and In, if necessary, Ce, and Cr, and is the total of Al and the second element M. When the molar composition ratio is 5, the molar composition ratio of Ce is the product of the variables x and 3, the molar composition ratio of Cr is the product of the variables y and 3, and the variable x exceeds 0.0002. Includes at least one phosphor selected from the group consisting of second aluminate phosphors having a number less than 0.50 and having the variable y greater than 0.0001 and less than 0.05. It is a light emitting device.

A second aspect of the present invention is a lighting device in which the light emitting device and a light source that emits light energy different from the light emitting device are combined.

A third aspect of the present invention is a plant cultivation method in which a plant is irradiated with light emitted from the light emitting device.

According to the present invention, it is possible to provide a light emitting device, a lighting device and a plant cultivation method capable of promoting the growth of plants.

FIG. 1 is a schematic cross-sectional view showing an example of a light emitting device. FIG. 2 shows the wavelengths of the light emitting devices according to Examples 1 to 5 and Comparative Example 1 and the spectra of the relative photon flux. FIG. 3 shows the wavelengths of the light emitting devices according to Examples 6 to 10 and Comparative Example 2 and the spectra of the relative photon flux. FIG. 4 shows the wavelengths of the light emitting devices according to Examples 11 to 15 and Comparative Example 3 and the spectra of the relative photon flux. FIG. 5 shows the wavelengths of the light emitting devices according to Examples 16 to 20 and Comparative Example 3 and the spectra of the relative photon flux. FIG. 6 shows the wavelengths of the light emitting devices according to Examples 21 to 23 and Comparative Example 3 and the spectra of the relative photon flux. FIG. 7 shows the wavelengths of the light emitting devices according to Examples 24 to 26 and Comparative Example 3 and the spectra of the relative photon flux. FIG. 8 shows the relationship between the content of the second phosphor in the light emitting devices according to Examples 1 to 26 and the ratio R / Fr of the photon bundle R of red light to the photon bundle Fr of far red light. It is a graph which shows. FIG. 9 shows the wavelength and the spectrum of the relative photon flux of the light source for emitting white light and the light source for plant cultivation using the light emitting device of the example or the comparative example in combination. _{FIG. 10 is a graph showing the relationship between the temperature and peak wavelength of CaAlSiN 3} : Eu (660CASN), which is the first phosphor, and a red LED having an emission peak wavelength in the vicinity of 660 nm. FIG. 11 is a graph showing the relationship between the plant height (Plant Height (cm)) of romaine lettuce described in Non-Patent Document 1 and the ratio R / Fr.

Hereinafter, an embodiment of a light emitting device, a lighting device, and a plant cultivation method according to the present invention will be described. However, one aspect of the implementation shown below is an example for embodying the technical idea of the present invention, and the present invention is not limited to the following light emitting device, lighting device and plant cultivation method. The relationship between the color name and the chromaticity coordinate, the relationship between the wavelength range of light and the color name of monochromatic light, etc., follow JIS Z8110.

Light emitting device The first embodiment of the present invention comprises a light emitting element having a light emitting peak wavelength within a wavelength range of 380 nm or more and 490 nm or less (hereinafter, may be referred to as “near-ultraviolet to blue region”), and the light emitting element. A first phosphor that is excited by light from and emits light having at least one emission peak wavelength within a wavelength range of 580 nm or more and less than 680 nm, and a wavelength range of 680 nm or more and 800 nm or less that is excited by light from the light emitting element. A second phosphor that emits light having at least one emission peak wavelength is provided therein, and an optical quantum bundle B of blue light in a wavelength range of 400 nm or more and 490 nm or less (hereinafter, an optical quantum bundle of blue light in a wavelength range of 400 nm or more and 490 nm or less). B is also referred to as "blue light quantum bundle B"), and red light optical quantum bundle R in a wavelength range of 620 nm or more and less than 700 nm (hereinafter, red light optical quantum bundle R in a wavelength range of 620 nm or more and less than 700 nm is "red light". The ratio R / B of (also referred to as "photon flux R") is more than 4 and 50 or less, and the photon flux Fr of far-red light in the wavelength range of 700 nm or more and 780 nm or less (hereinafter, 700 nm or more and 780 nm or less) The ratio R / Fr of the photon flux R of red light to the photon flux Fr of far-red light is also referred to as "photon flux Fr of far-red light"), and the second phosphor is 1. The first element Ln and Al containing at least one element selected from the group consisting of Al, a first aluminate phosphor having a composition containing Cr, and a rare earth element excluding Ce, and Al, if necessary. It has a composition containing a second element M containing at least one element selected from the group consisting of Ga and In, Ce, and Cr, and the total molar composition ratio of Al and the second element M is set to 5. Sometimes, the molar composition ratio of Ce is the product of the variables x and 3, the molar composition ratio of Cr is the product of the variables y and 3, and the variable x is more than 0.0002 and less than 0.50. A light emitting device, which is at least one type of phosphor selected from the group consisting of a second aluminate phosphor whose variable y is greater than 0.0001 and less than 0.05. As used herein, the "molar composition ratio" represents the molar ratio of each element in 1 molar chemical composition representing a phosphor.

An example of the light emitting device according to the first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing a light emitting device 100 which is an example of a light emitting device according to the first embodiment of the present invention.

Light emitting device As shown in FIG. 1, the light emitting device 100 includes, for example, a molded body 40, a light emitting element 10, and a fluorescent member 50 as a support. The molded body 40 is formed by integrally molding a first lead 20 and a second lead 30 and a resin portion 42 containing a thermoplastic resin or a thermosetting resin. The molded body 40 forms a recess having a bottom surface and a side surface, and a light emitting element 10 is arranged on the bottom surface of the recess. The light emitting element 10 has a pair of positive and negative electrodes, and the pair of positive and negative electrodes are electrically connected to the first lead 20 and the second lead 30, respectively, via a wire 60. The light emitting element 10 is covered with a fluorescent member 50. The fluorescent member 50 includes, for example, a phosphor 70 for wavelength-converting the light from the light emitting element 10 and a resin. The phosphor 70 includes a first phosphor 71 and a second phosphor 72. A part of the first lead 20 and the second lead 30 connected to the pair of positive and negative electrodes of the light emitting element 10 is exposed to the outside of the package constituting the light emitting device 100. Through these first leads 20 and second leads 30, electric power can be supplied from the outside to cause the light emitting device 100 to emit light.

The light emitting device 100 has a light emitting element 10 having an emission peak wavelength in the wavelength range of 380 nm or more and 490 nm, and at least one emission peak wavelength in the wavelength range of 580 nm or more and less than 680 nm excited by the light from the light emitting element 10. It includes a first phosphor 71 that emits the light having the light, and a second phosphor 72 that is excited by the light from the light emitting element 10 and emits light having at least one emission peak wavelength within a wavelength range of 680 nm or more and 800 nm or less.

In plants, the photoreceptors (chlorophyll a and chlorophyll b) present in the chloroplast absorb light, take in carbon dioxide gas and water, and convert them into carbohydrates (sugars) by photosynthesis. grow up. Chlorophyll a and chlorophyll b used for promoting plant growth have absorption peaks particularly in the red region of 625 nm or more and 675 nm or less and in the blue region of 425 nm or more and 475 nm or less. Photosynthesis by chlorophyll in plants occurs mainly in the wavelength range of 400 nm or more and 700 nm or less, but further, chlorophyll a and chlorophyll b have local absorption peaks even in the region of 700 nm or more and 800 nm or less. For example, when light having a wavelength longer than the absorption peak (around 680 nm) in the red region of chlorophyll a is applied, a phenomenon called red drop occurs in which the activity of photosynthesis suddenly decreases. However, it is known that when light including a far red region of 700 nm or more is irradiated together with light in the red region, photosynthesis is activated by the synergistic effect of these two types of light. This phenomenon is called the Emerson effect.

In addition, plants have phytochrome, which is a photoreceptor for red light and far-red light, as a photoreceptor (pigment). Among phytochromes, there are red light absorption type (Pr type) phytochrome that absorbs red light having an emission peak wavelength near 660 nm and far red light absorption type (Pfr type) phytochrome having an emission peak wavelength near 730 nm. do. Red light absorption type (Pr type) phytochrome is inactive type, and far red light absorption type (Pfr type) phytochrome is active type. Light reversibly transforms molecular function, triggering various photoresponses and promoting photomorphogenesis in various plants such as seed germination induction, leaflet development, and stalk elongation.

As mentioned above, the index of energy radiated from a light source for plant cultivation is represented by a photon Flux. In addition, the index of the amount of light irradiated to the plant is expressed by the photon Flux Density. The photon flux density (μmol · m ^-2 · s ^-1 ) is the number of photons that reach a unit area per unit time. The magnitude of red and far-red light acting on plant photomorphogenesis depends on the number of photons. The amount of energy of a photon changes in inverse proportion to its wavelength. Assuming that Planck's constant (6.63 × 10 ⁻³⁴ Js) is h, the speed of light is c (3 × 10 ⁸ m / s), and the wavelength is λ (m), the photon energy e is expressed by the equation e = hc / λ. Will be done.

In the light emitting device, the ratio R / B of the photon bundle R of red light to the photon bundle B of blue light is more than 4 and 50 or less, and the ratio R / B of the photon bundle R of red light to the photon bundle Fr of far red light. Fr is 0.1 or more and 10 or less. When the range of the ratio R / B and the range of the ratio R / Fr of the light emitted from the light emitting device are within the above range, the light emitted from the light emitting device causes the red light absorption type contained in the plant. Red light and far-red light are absorbed by two photoreceptors, (Pr type) phytochrome and far-red light absorption type (Pfr) phytochrome, and a photoresponse is triggered. Then, the light emitted from the light emitting device promotes the reaction of photomorphogenesis of the plant irradiated with the light, and promotes the growth of the plant. Further, since the ratio R / Fr of the light emitted from the light emitting device is in the above range, the plant irradiated with the light from the light emitting device contains the light in the red region and the light containing a far red region of 700 nm or more. Is irradiated. In plants irradiated with light from the light emitting device, photosynthesis is activated and plant growth is promoted by a synergistic effect (Emmerson effect) of two types of light, light in the red region and light in the near infrared region.

The ratio R / B of the light emitted from the light emitting device is preferably 5 or more and 48 or less, more preferably 6 or more and 45 or less, still more preferably 7 or more and 40 or less, and further preferably more than 8. 38 or less, and particularly preferably more than 10 and 38 or less. The ratio R / B is the ratio of the photon bundle R of red light to the photon bundle B of blue light of the light emitted from the light emitting device. When the ratio R / B of the light emitted from the light emitting device is within the above range, the light emitted from the light emitting device is efficiently absorbed by the photoreceptors of the plant forming the photomorphogenesis. The ratio R / Fr of the light emitted from the light emitting device is preferably 0.2 or more and 8 or less, more preferably 0.3 or more and 7 or less, still more preferably 0.4 or more and 6 or less, and more. It is more preferably 0.5 or more and 5 or less, still more preferably 1.5 or more and 4.2 or less, still more preferably 1.5 or more and 4.12 or less, and particularly preferably 1.5 or more and 4 or less. It is less than or equal to 0.0. The ratio R / Fr is the ratio of the photon bundle R of red light to the photon bundle Fr of far-red light of the light emitted from the light emitting device. When the ratio R / Fr of the light emitted from the light emitting device is within the above range, the light from the light emitting device is efficiently absorbed by the photoreceptors of the plant that form the photomorphogenesis.

The photon flux (μmol · s ^-1 or mol · s ^-1 ) can be converted from the radiant flux (W). The relationship between the radiant flux and the photon flux is expressed by the following equation (1).
Radiant flux (W) = Photon flux (mol · s ^-1 ) x Avogadro's number (mol ^-1 ) x Planck's constant (Js) x Speed of light (m · s ^-1 ) ÷ Wavelength (m) (1)
The radiant flux (W) obtained from the light emitting device is converted into a photon flux based on the above equation (1). The photon bundle B of blue light can be calculated by integrating the photon bundles in the wavelength range of 400 nm or more and 490 nm or less. Further, the photon bundle R of red light can be calculated by integrating the photon bundles in the wavelength range of 620 nm or more and less than 700 nm obtained from the light emitting device. Further, the photon bundle Fr of far-red light can be calculated by integrating the photon bundles in the wavelength range of 700 nm or more and 780 nm or less obtained from the light emitting device.

Light emitting element The light emitting element is used as an excitation light source and is a light emitting element that emits light having a emission peak wavelength within a wavelength range of 380 nm or more and 490 nm or less.
The emission peak wavelength of the light emitting device is more preferably 390 nm or more and 480 nm or less, further preferably 420 nm or more and 470 nm or less, still more preferably 440 nm or more and 460 nm or less, and particularly preferably 445 nm or more and 455 nm or less. As such a light emitting device, it is preferable to use a light emitting device containing a nitride semiconductor (In _X Al _Y Ga _1-XY N, 0 ≦ X, 0 ≦ Y, X + Y ≦ 1). The half width of the emission spectrum of the light emitting element can be, for example, 30 nm or less.

The light emitting device is excited by the first phosphor that is excited by the light from the light emitting element and emits light having at least one light emission peak wavelength within the wavelength range of 580 nm or more and less than 680 nm, and is excited by the light from the light emitting element. A second phosphor that emits light having at least one emission peak wavelength within a wavelength range of 680 nm or more and 800 nm or less is provided. The following description will be given in the order of the second fluorescent substance and the first fluorescent substance for convenience.

Second Fluorescent Material The second phosphor is excited by light from a light emitting element and emits light having at least one emission peak wavelength within a wavelength range of 680 nm or more and 800 nm or less.
The second phosphor is the first element Ln containing at least one element selected from the group consisting of Al, a first aluminate phosphor having a composition containing Cr, and a rare earth element excluding Ce, and Al. And, if necessary, has a composition containing a second element M containing at least one element selected from the group consisting of Ga and In, Ce, and Cr, and the total molar amount of Al and the second element M. When the composition ratio is 5, the molar composition ratio of Ce is the product of the variables x and 3, the molar composition ratio of Cr is the product of the variables y and 3, and the variable x exceeds 0.0002 and is 0. Includes at least one element selected from the group consisting of second aluminate phosphors having a number less than .50 and having the variable y greater than 0.0001 and less than 0.05.
In the first aluminate phosphor, Cr is an activating element. In the second aluminate phosphor, Ce and Cr are activating elements. In the composition of the second aluminate phosphor, when the total molar composition ratio of Al and the second element M is 5, the molar composition ratio of Ce is represented by the product of the variables x and 3, and the molar of Cr. When the composition ratio is represented by the product of the variables y and 3, the variable x is a number that exceeds 0.0002 and satisfies less than 0.50 (0.0002 <x <0.50), and the variable y is 0. When the number is more than 0001 and less than 0.05 (0.0001 <y <0.05), the amount of activation of Ce, which is the emission center contained in the crystal structure of the second aluminate phosphor, is activated. And Cr activation amount is in the optimum range, and it is possible to suppress the decrease in emission intensity due to the decrease in the number of emission centers, and conversely, the decrease in emission intensity due to concentration extinction caused by the increase in activation amount is suppressed. The emission intensity can be increased.

The second phosphor is a group consisting of a first aluminate phosphor having a composition represented by the following formula (I) and a second aluminate phosphor having a composition represented by the following formula (II). It is preferable to contain at least one fluorescent substance selected from the above.
(Al _1-w Cr _w ) ₂ O ₃ (I)
(In formula (I), w is a number satisfying 0 <w <1.)
_{(Ln 1-x-y Ce} x Cr y) 3 (Al 1-z M z) 5 O 12 (II)
(In formula (II), Ln is at least one rare earth element selected from the group consisting of rare earth elements excluding Ce, and M is at least one element selected from the group consisting of Ga and In. x, y and z are numbers that satisfy 0.0002 <x <0.50, 0.0001 <y <0.05, 0≤z≤0.8).

The second phosphor contains at least one kind of aluminate phosphor, and may contain two or more kinds of aluminate phosphors. Cr contained in the first aluminate phosphor having the composition represented by the formula (I) is an activating element. In the formula (I), the product of the variables w and 2 is the molar composition ratio of the activating element Cr in the composition represented by the formula (I). The variable w is preferably 0 <w <1, more preferably 0.00005 ≦ w ≦ 0.25, still more preferably 0.0005 ≦ w ≦ 0.15, still more preferably 0.001 ≦ w ≦ 0. It is 07. When the variable w exceeds 0 and is less than 1, Cr, which is an activating element that is the center of emission, is contained, and the emission intensity can be increased.

Ce and Cr in the formula (II) are activating elements of the second aluminate fluorophore having the composition represented by the formula (II). In the formula (II), the product of the variables x and 3 is the molar composition ratio of the activating element Ce in the composition represented by the formula (II). The variable x is preferably 0.0002 <x <0.50, more preferably 0.001 ≦ x ≦ 0.35, and even more preferably 0.0015 ≦ x ≦ 0.30. In the formula (II), the product of the variables y and 3 is the molar composition ratio of the activating element Cr in the composition represented by the formula (II). The variable y is preferably 0.0001 <y <0.05, more preferably 0.0005 ≦ y ≦ 0.04, and even more preferably 0.001 ≦ y ≦ 0.026.

In the formula (II), Ln is at least one kind of rare earth element selected from the group consisting of rare earth elements other than Ce, and more preferably selected from the group consisting of Y, Gd, Lu, La, Tb and Pr. At least one selected from the group consisting of Y, Gd and Lu.

In the formula (II), M is preferably at least one element selected from the group consisting of Ga and In, and M is preferably contained in Ga. In the formula (II), the product of the variables z and 5 is the molar composition ratio of the element M that replaces Al in the formula (II). In the formula (II), the variable z is preferably 0 ≦ z ≦ 0.8, more preferably 0.001 ≦ z ≦ 0.6, and further preferably 0.01 ≦ z ≦ 0.4. Is.

At least one kind of aluminate phosphor contained in the second phosphor has a composition constituting a garnet structure, and is therefore resistant to heat, light and moisture. At least one kind of aluminate phosphor contained in the second phosphor has an absorption peak wavelength of 420 nm or more and around 470 nm in the excitation absorption spectrum, and sufficiently absorbs the light from the light emitting element to emit light of the second phosphor. The strength can be increased. Specifically, the at least one kind of aluminate phosphor contained in the second phosphor is, for example, (Al _0.09 Cr _0.01 ) ₂ O ₃ , (Al _0.9943 Cr _0.0057 ) ₂ O. ₃ , (Y _0.977 Ce _0.009 Cr _0.014 ) ₃ Al ₅ O ₁₂ , (Lu _0.983 Ce _0.009 Cr _0.008 ) ₃ Al ₅ O ₁₂ , (Lu _0.9725 Ce _{0. 0175} Cr _0.01 ) ₃ Al ₅ O ₁₂ , (Y _0.9735 Ce _0.0125 Cr _0.014 ) ₃ (Al _0.8 Ga _0.2 ) ₅ O ₁₂ , (Y _0.7836 Gd _0.1959) Ce _0.0125 Cr _0.008 ) ₃ Al ₅ O ₁₂ , (Gd _0.9675 Ce _0.0125 Cr _0.02 ) ₃ Al ₅ O _{12 and the} like can be mentioned.

Method for Producing Second Fluorescent Material As an example of the method for producing at least one kind of aluminate phosphor contained in the second phosphor, the following method can be mentioned.
It contains at least one compound containing the rare earth element Ln selected from the group consisting of rare earth elements excluding Ce, a compound containing Al, and at least one element M selected from the group consisting of Ga and In, if necessary. When the compound, the compound containing Ce, and the compound containing Cr are based on the total molar composition ratio of Al and the element M of 5, the total molar composition ratio of the rare earth elements Ln, Ce, and Cr is 3. , The molar composition ratio of Ce is the product of variables x and 3, and when the molar composition ratio of Cr is the product of variables y and 3, the variable x is a number greater than 0.0002 and less than 0.50. , Each raw material is weighed so that the variable y is a number of more than 0.0001 and less than 0.05. When the molar composition ratio of the element M is the product of the variable z and 5, it is preferable to weigh the compound containing the element M so that the variable z is 0 or more and 0.8 or less. Each of the above raw materials is mixed to obtain a raw material mixture. This raw material mixture is heat-treated, and then, if necessary, post-treatment steps such as solid-liquid separation by a method such as washing and filtration, drying by a method such as vacuum drying, and classification by a dry sieve are performed, and a second aluminon is performed. A hydrochloride phosphor is obtained. As a method for producing the second aluminate phosphor, Japanese Patent Application No. 2014-260421, which the applicant has previously applied for a patent, may be referred to.

Examples of the compound as a raw material include oxides, hydroxides, nitrides, oxynitrides, fluorides, chlorides and the like. These compounds may be hydrates. Compared with other materials, each of the above compounds does not contain any other element other than the desired composition, and it is easy to obtain a phosphor having the desired composition, so that it is preferably an oxide. Specifically, Y ₂ O ₃ , Gd ₂ O ₃ , Lu ₂ O _3, La ₂ O ₃ , Tb ₄ O ₇ , Pr ₆ O ₁₁ , Al ₂ O ₃ , Ga ₂ O ₃ , In ₂ O ₃ , Examples thereof include _{CeO 2} and Cr ₂ O _3. The raw material mixture may contain a flux such as a halide, if necessary. By containing the flux in the raw material mixture, the reaction between the raw materials is promoted, and the solid phase reaction is likely to proceed more uniformly. Specific examples of the flux include BaF ₂ , CaF _{2, and the} like. BaF ₂ is preferred. This is because the garnet crystal structure is stabilized by using barium fluoride as the flux, and the garnet crystal structure is likely to be formed.
The temperature for heat treatment is preferably 1000 ° C. or higher and 2100 ° C. or lower from the viewpoint of the stability of the crystal structure. The heat treatment time varies depending on the rate of temperature rise, the heat treatment atmosphere, and the like, and is preferably 1 hour or more and 20 hours or less after reaching the heat treatment temperature. The atmosphere for heat-treating the raw material mixture can be an inert atmosphere such as argon or nitrogen, a reducing atmosphere containing hydrogen or the like, or an oxidizing atmosphere such as in the atmosphere.

First Fluorescent Material The first phosphor is a phosphor that is excited by light from a light emitting element and emits light having at least one emission peak wavelength within a wavelength range of 580 nm or more and less than 680 nm.
The first fluorophore is at least selected from the group consisting of ^{Eu 2 +} activated nitride phosphor, Mn ^{4 +} activated fluorogermanate phosphor, Eu 2 ⁺ activated alkaline earth sulfide phosphor, and Mn ^{4 + activated halide phosphor.} It preferably contains a kind of first phosphor. As the first fluorescent substance, one kind of fluorescent substance may be used alone, or two or more kinds of fluorescent substances may be combined. The first fluorescent substance preferably contains, for example, at least one fluorescent substance selected from the group consisting of fluorescent substances having any composition represented by the following formulas (III) to (VIII).

The first phosphor preferably contains a nitride phosphor having a composition containing at least one element selected from Sr and Ca, Eu, Al, and Si. For example, as the first phosphor, a nitride phosphor represented by _{(Sr, Ca) AlSiN 3: Eu can be mentioned as a composition formula.} In the present specification, the plurality of elements described separated by commas (,) in the composition formula means that at least one element among these plurality of elements is contained in the composition. The plurality of elements described separated by commas (,) in the composition formula include at least one element selected from the plurality of elements separated by commas in the composition, and two of the plurality of elements. The above may be included in combination.

The first phosphor preferably contains a nitride phosphor having a composition represented by the following formula (III).
(Ca _1-p-q Sr _p Eu _q ) AlSiN ₃ (III)
(In formula (III), p and q are numbers satisfying 0 ≦ p ≦ 1.0, 0 <q <0.5, 0 <p + q ≦ 1.0).

In the above formula (III), Eu is an activating element of the nitride phosphor. In the formula (III), the variable q is the molar composition ratio of the activating element Eu in the composition represented by the formula (III). The variable q is preferably 0.0001 ≦ q ≦ 0.4, more preferably 0.001 ≦ q ≦ 0.3, and even more preferably 0.0015 ≦ q ≦ 0.2. In the formula (III), the variable p is the molar composition ratio of Sr in the composition represented by the formula (III). The variable p is preferably 0.001 ≦ p <0.9, more preferably 0.002 ≦ p ≦ 0.8, and even more preferably 0.003 ≦ p ≦ 0.76.

^{The first fluorescent substance may contain an Eu 2+} activated nitride fluorescent substance different from the nitride fluorescent substance having the composition represented by the above formula (III).
The Eu ²⁺ activated nitride phosphor is a group consisting of an alkaline earth metal element in addition to a nitride phosphor having a composition containing at least one element selected from Sr and Ca, Eu, Al, and Si. Examples thereof include a phosphor having an at least one element selected from the above elements and at least one element selected from the group consisting of alkali metal elements in a composition and containing an aluminum nitride activated by ^{Eu 2+.}
Halide phosphor activated with Mn ⁴⁺ is at least a one element or ion, the group consisting of Group IV and Group 14 element selected from the group consisting of alkali metal elements and ammonium ion (NH 4 ^₊₎ It is preferable that the phosphor has at least one element selected from the above ^{and contains a fluoride activated by Mn 4+.}

The first fluorescent substance may contain at least one kind of fluorescent substance selected from the group consisting of fluorescent substances having any composition represented by the following formulas (IV) to (VIII).

(I-j) MgO · (j / 2) Sc ₂ O ₃ · kmgF ₂ · mCaF ₂ · (1-n) GeO ₂ · (n / 2) M ¹ O ₃ : vMn ⁴⁺ (IV)
In formula (IV), M ¹ is at least one selected from the group consisting of Al, Ga and In, and i, j, k, m, n and v are 2≤i≤4 and 0≤j <, respectively. It is a number that satisfies 0.5, 0 <k <1.5, 0 ≦ m <1.5, 0 <n <0.5, and 0 <v <0.05.

M ² _d M ³ _e M ⁴ _f Al _3-g Si _g N _h (V)
In formula (V), M ² is at least one element selected from the group consisting of Ca, Sr, Ba and Mg, and M ³ is at least one selected from the group consisting of Li, Na and K. It is an element, M ⁴ is at least one element selected from the group consisting of Eu, Ce, Tb and Mn, and d, e, f, g and h are 0.80 ≦ d ≦ 1.05, respectively. , 0.80 ≦ e ≦ 1.05, 0.001 <f ≦ 0.1, 0 ≦ g ≦ 0.5, 3.0 ≦ h ≦ 5.0.

(Ca _1-r-s-t Sr _r Ba _s Eu _t ) ₂ Si ₅ N ₈ (VI)
In equation (VI), r, s and t are numbers satisfying 0 ≦ r ≦ 1.0, 0 ≦ s ≦ 1.0, 0 <t <1.0 and r + s + t ≦ 1.0.

(Ca, Sr) S: Eu (VII)

A ₂ [M ⁵ _1-u Mn ^{4 +} _u F ₆ ] (VIII)
Wherein (VIII), A is K, Li, is at least one Na, Rb, are chosen from Cs, and the group consisting of _NH ^{4 +, M 5} is the group consisting of Group IV and Group 14 elements It is at least one element selected from, and u is a number satisfying 0 <u <0.2.

Mass ratio of first phosphor and second phosphor The mass ratio of the second phosphor to the total amount of 100 mass% of the first phosphor and the second phosphor is the ratio R / B of the light emitted from the light emitting device. The amount is more than 4 and 50 or less, and the ratio R / Fr of the light emitted from the light emitting device is 0.1 or more and 10 or less. The light emitted from the light emitting device is a mixture of light emitted from the first phosphor and the second phosphor excited by the light from the light emitting element and light from the light emitting element. The ratio R / B of the light emitted from the light emitting device is the ratio of the photon bundle R of red light to the photon bundle B of blue light. The ratio R / Fr of the light emitted from the light emitting device is the ratio of the photon bundle R of the red light to the photon bundle Fr of the far red light. The mass ratio of the second phosphor to 100% by mass of the total amount of the first phosphor and the second phosphor is preferably in the range of 0.5% by mass or more and 99.5% by mass or less, and more preferably 1. It is in the range of mass% or more and 99% by mass or less, more preferably 1% by mass or more and 90% by mass or less, still more preferably 2% by mass or more and 80% by mass or less, and further preferably 5 It is in the range of mass% or more and 78% by mass or less, and particularly preferably in the range of more than 10% by mass and 75% by mass or less. When the mass ratio of the second phosphor to 100% by mass of the total amount of the first phosphor and the second phosphor is within the above range, the light from the light emitting element having the emission peak wavelength within the wavelength range of 380 nm or more and 490 nm or less. At the same time, the ratio R / B is more than 4 and 50 or less, and the ratio R / Fr is 0.1 or more and 10 or less due to the light emitted from the first phosphor and the second phosphor excited by the light from the light emitting element. The mixed color light can be controlled so as to irradiate the light of. When the mass ratio of the second phosphor to 100% by mass of the total amount of the first phosphor and the second phosphor is in the range of 2% by mass or more and 80% by mass or less, the ratio R / B exceeds 10 and 38. It can be as follows, the ratio R / Fr can be 1.5 or more and 4.12 or less, and it is a light emitting device that irradiates light that is more easily absorbed by the photoreceptors of plants and easily promotes the formation of light morphology. Can be provided. When the mass ratio of the second phosphor to 100% by mass of the total amount of the first phosphor and the second phosphor is in the range of more than 10% by mass and 75% by mass or less, the ratio R / B exceeds 10 and 38. The light emission can be as follows, the ratio R / Fr can be 1.5 or more and 4.0 or less, the light acceptor of the plant is more easily absorbed, and the photomorphogenesis is more easily promoted. Equipment can be provided.

Fluorescent member The fluorescent member includes a fluorescent substance containing a first fluorescent substance and a second fluorescent substance, and a resin. As shown in FIG. 1, the fluorescent member 50 not only converts the wavelength of the light emitted by the light emitting element 10 into wavelength, but also functions as a member for protecting the light emitting element 10 from the external environment. The fluorescent substance 70 in the fluorescent member 50 includes a first fluorescent substance 71 and a second fluorescent substance 72.
The fluorescent member 50 containing the fluorescent substance 70 is formed so as to cover the light emitting element 10 placed in the recess of the molded body 40. Considering the ease of manufacture, a modified silicone resin such as a silicone resin, an epoxy resin, or an epoxy-modified silicone resin can be used as the resin contained in the fluorescent member 50. In FIG. 1, the fluorescent substance 70 exists in the fluorescent member 50 in a state where the first fluorescent substance 71 and the second fluorescent substance 72 are mixed, and the composition for the fluorescent member is arranged so as to cover the light emitting element 10. , Form a fluorescent member. As a result, the light from the light emitting element 10 can be efficiently wavelength-converted by the phosphor 70, and a light emitting device having excellent light emitting efficiency can be provided. As shown in FIG. 1, the arrangement of the fluorescent member 50 including the phosphor 70 and the light emitting element 10 is not limited to the mode in which the fluorescent body 70 is arranged close to the light emitting element 10, and is generated from the light emitting element 10. In consideration of the influence of the heat generated, the phosphor 70 may be arranged by providing a gap with the light emitting element 10 in the fluorescent member 50. Further, by arranging the phosphors 70 substantially evenly in the fluorescent member 50, it is possible to emit light with suppressed color unevenness from the light emitting device 100. In FIG. 1, in the fluorescent substance 70, the first fluorescent substance 71 and the second fluorescent substance 72 are arranged in a mixed manner. For example, the fluorescent member 50 is divided into a plurality of portions, and the first fluorescent substance 71 is mainly used. A site mainly containing the second phosphor 72 may be arranged on the site containing the second phosphor 72, and the order may be reversed.

The fluorescent member preferably contains a total amount of the first fluorescent substance and the second fluorescent substance in an amount of 5 parts by mass or more and 150 parts by mass or less with respect to 100 parts by mass of the resin. When the total amount of the first phosphor and the second phosphor with respect to the resin in the fluorescent member is within the above range, the light emitted from the light emitting element is efficiently wavelength-converted to cause the formation of the light form of the plant. Absorption-type (Pr-type) phytochrome and far-red light Absorption-type (Pfr-type) phytochrome can irradiate red light and far-red light in a wavelength range easily absorbed by the photoreceiver from the light emitting device.
The total amount of the first fluorescent substance and the second fluorescent substance in the fluorescent member is more preferably 10 parts by mass or more and 140 parts by mass or less, still more preferably 15 parts by mass, based on 100 parts by mass of the resin contained in the fluorescent member. It is 120 parts by mass or less, more preferably 20 parts by mass or more and 100 parts by mass or less.

The fluorescent member preferably contains 0.5 parts by mass or more and 100 parts by mass or less of the second phosphor with respect to 100 parts by mass of the resin. When the fluorescent member contains 0.5 parts by mass or more and 100 parts by mass or less of the second phosphor with respect to 100 parts by mass of the resin, the light emitted from the light emitting device provided with the fluorescent member is blue light. The ratio R / B of the photon bundle R of red light to the photon bundle B of is more than 4 and 50 or less, and the ratio R / Fr of the photon bundle R of red light to the photon bundle Fr of far-red light is 0.1 or more. It can be 10 or less. When the content of the second phosphor with respect to the resin in the fluorescent member is within the above range, the ratio R / B is more than 4 and 50 or less, and the ratio R / Fr is 0.1 or more and 10 or less. , Light that promotes photomorphogenesis of plants can be emitted from the light emitting device.
The content of the second phosphor in the fluorescent member is more preferably 1 part by mass or more and 95 parts by mass or less, still more preferably 2 parts by mass or more and 90 parts by mass or less, based on 100 parts by mass of the resin in the fluorescent member. More preferably, it is 3 parts by mass or more and 80 parts by mass or less.

The content of the first phosphor in the fluorescent member is such that the ratio R / B of the photon bundle R of red light to the photon bundle B of blue light of light emitted from a light emitting device provided with the fluorescent member exceeds 4 and is 50 or less. The amount is not particularly limited as long as the ratio R / Fr of the photon bundle R of red light to the photon bundle Fr of far-red light is 0.1 or more and 10 or less. The content of the first phosphor in the fluorescent member is, for example, 1 part by mass or more, preferably 5 parts by mass or more, more preferably 10 parts by mass or more, still more preferably 10 parts by mass or more, based on 100 parts by mass of the resin in the fluorescent member. Is 15 parts by mass or more, preferably 149 parts by mass or less, more preferably 140 parts by mass or less, and further preferably 100 parts by mass or less. When the content of the first phosphor in the fluorescent member is within the above range, the light emitted from the light emitting element can be efficiently wavelength-converted by the first phosphor, and the light that promotes the photomorphogenesis of the plant is promoted. Can be emitted from the light emitting device.

In addition to the first fluorescent substance, the second fluorescent substance, and the resin, the fluorescent member may contain other components such as a filler, a light stabilizer, and a colorant. Examples of the filler include silica, barium titanate, titanium oxide, aluminum oxide and the like. The other components contained in the fluorescent member are preferably 0.01 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the resin contained in the fluorescent member.

In other phosphor fluorescent members, the ratio R / B of the light quantum bundle R of red light to the light quantum bundle B of blue light is more than 4 and 50 or less, and the photon of far-red light is emitted from the light emitting device. As long as the ratio R / Fr of the photon flux R of red light to the bundle Fr is 0.1 or more and 10 or less, other types of phosphors may be contained in addition to the first phosphor and the second phosphor.
Other types of phosphors include a green phosphor that absorbs a part of the light emitted from the light emitting element and emits green light, a yellow fluorescent substance that emits yellow light, and an emission peak wavelength in a wavelength range exceeding 680 nm. Examples thereof include a fluorescent substance having the above.

Specific examples of the green phosphor include a fluorescent substance having any composition represented by the following formulas (i) to (iii).
M ¹¹ ₈ MgSi ₄ O ₁₆ X ¹¹ : Eu (i)
In formula (i), M ¹¹ is at least one selected from the group consisting of Ca, Sr, Ba and Zn, and X ¹¹ is at least one selected from the group consisting of F, Cl, Br and I.

Si _6-a Al _a O _a N _8-a : Eu (ii)
In equation (ii), a satisfies 0 <a <4.2.

M ¹³ Ga ₂ S ₄ : Eu (iii)
In formula (iii), M ¹³ is at least one selected from the group consisting of Mg, Ca, Sr and Ba.

Specific examples of the yellow fluorescent substance include a fluorescent substance having any composition represented by the following formulas (iv) to (v).
M ¹⁴ _{b / c} Si _{12- (b + c)} Al _{(b + c)} O _c N _(16-c) : Eu (iv)
In formula (iv), M ¹⁴ is at least one selected from the group consisting of Sr, Ca, Li and Y. b is 0.5 to 5, c is 0 to 2.5, and c is the charge of ^{M 14.}

M ¹⁵ ₃ Al ₅ O ₁₂ : Ce (v)
In formula (v), M ¹⁵ is at least one selected from the group consisting of Y, Lu, Tb and Gd. A part of Al may be replaced with Ga.

Specific examples of the phosphor having an emission peak wavelength in the wavelength range exceeding 680 nm include a fluorescent substance having any composition represented by the following formulas (vi) to (ix).
(Ca, Sr, Ba) (Y, Gd, La) (Al, Ga) _1-a1 Mg _a1 O ₄ : Mn (0≤a1≤0.2) (vi)
Li (Al, Ga) O ₂ : Fe (vii)
CdS: Fe (viii)
(Gd, Y, La, Tb) (Al, Sc, Ga) O ₃ : Cr (ix)

Composition for Fluorescent Member The composition contains 5 parts by mass or more and 150 parts by mass or less of the total of the first fluorescent substance and the second fluorescent substance with respect to 100 parts by mass of the resin. In the above composition, the mass ratio of the second phosphor to the total amount of the first phosphor and the second phosphor is the light emitted from the first and second phosphors excited by the light from the light emitting element and the light emitted. The ratio R / B of the optical quantum bundle R of red light to the optical quantum bundle B of blue light mixed with the light from the element is an amount exceeding 4 and 50 or less, and the red light with respect to the optical quantum bundle Fr of far-red light. The ratio R / Fr of the photon flux R is 0.1 or more and 10 or less. The mass ratio of the second phosphor to 100% by mass of the total amount of the first phosphor and the second phosphor contained in the composition is preferably in the range of 0.5% by mass or more and 99.5% by mass or less. It is more preferably 1% by mass or more and 99% by mass or less, further preferably 1% by mass or more and 90% by mass or less, and further preferably 2% by mass or more and 80% by mass or less. It is more preferably in the range of 5% by mass or more and 78% by mass or less, and particularly preferably in the range of more than 10% by mass and 75% by mass or less. When the mass ratio of the second phosphor to the total amount of the first phosphor and the second phosphor contained in the composition is within the above range, a light emitting element having an emission peak wavelength within the wavelength range of 380 nm or more and 490 nm or less. The ratio R / B of the light quantum bundle R of red light to the light quantum bundle B of blue light is 4 due to the light emitted from the first phosphor and the second phosphor excited by the light from the light emitting element together with the light from. The mixed color light can be controlled so that the ratio R / Fr of the light quantum bundle R of the red light to the light quantum bundle Fr of the far red light is 0.1 or more and 10 or less. When the mass ratio of the second phosphor to 100% by mass of the total amount of the first phosphor and the second phosphor is in the range of 2% by mass or more and 80% by mass or less, the red light with respect to the photon bundle B of the blue light The ratio R / B of the photon bundle R can be more than 10 and 38 or less, and the ratio R / Fr of the photon bundle R of red light to the photon bundle Fr of far red light can be 1.5 or more and 4.12 or less. It is possible to manufacture a light emitting device that irradiates light that is more easily absorbed by plant photons and promotes light morphology formation. Further, when the mass ratio of the second phosphor to 100% by mass of the total amount of the first phosphor and the second phosphor is in the range of more than 10% by mass and 75% by mass or less, the red color of the blue light with respect to the photon bundle B is red. The ratio R / B of the photon bundle R of light can be more than 10 and 38 or less, and the ratio R / Fr of the photon bundle R of red light to the photon bundle Fr of far red light is 1.5 or more and 4.0. It is possible to provide a light emitting device that irradiates light which is more easily absorbed by a plant photon and more easily promotes light morphology formation.

When such a light emitting device is used, the light emitted from the light emitting device is easily absorbed by the photoreceiver of the plant that forms the photomorphogenesis, the photomorphogenesis of the plant is promoted, and the growth of the plant is promoted. be able to. The light emitting device is preferably used in combination with a light source that emits white light. White light is easily absorbed by photoreceptors of plants that perform photosynthesis such as chlorophyll of plants. For example, by using a light source that emits white light in combination with a light emitting device, photosynthesis of plants can be activated, photomorphogenesis of plants can be further promoted, and plant growth can be further promoted. Can be done. Examples of the white light include sunlight and light emitted from various lamps. As the light source that emits white light, for example, at least one light source selected from the sun, fluorescent lamps, incandescent lamps, metal halide lamps, high-pressure sodium lamps, and LED lamps can be used.

The light emitting device can be used as a light emitting device for supplementary light that promotes the growth of plants by using it in combination with a light source that emits white light. When used in combination with a light emitting device and a light source that emits white light, the photon of red light with respect to the photon bundle B of blue light that is a mixture of the light emitted from the light emitting device and the white light emitted from the light source. The ratio R / B of the bundle R may be preferably 1.0 or more and 10 or less, more preferably 1.5 or more and 8 or less, and further preferably 2.0 or more and 6 or less. Further, the ratio R / Fr of the photon bundle R of red light to the photon bundle Fr of far-red light of the light obtained by mixing the light emitted from the light emitting device and the white light emitted from the light source is preferably 0.1 or more. It may be 10 or less, more preferably 0.2 or more and 8 or less, still more preferably 0.3 or more and 7 or less, still more preferably 0.4 or more and 6 or less, and particularly preferably 0.5 or more and 5 or less.

Lighting device The light emitting device may be a lighting device combined with a light source that emits light energy different from this light emitting device. The light source that emits light energy different from that of the light emitting device may be a light source that emits white light. Further, the light source may be a light source that emits light other than white light, and examples thereof include a light source that emits blue light. A lighting device that combines a light emitting device and a light source that emits light energy different from the light emitting device can irradiate a plant with optimum light energy according to the degree of growth of the plant.

Plant cultivation method The plant cultivation method according to the embodiment of the present invention is a method of cultivating a plant by irradiating the plant with light emitted from a light emitting device. In the plant cultivation method, the light from the light emitting device 100 can be applied to the plant in a plant factory that is isolated from the external environment and can be artificially controlled. Further, for a plant cultivated in a house that uses sunlight, a light emitting device can be used to supplement the sunlight, and the light from the light emitting device can be applied to the plant. The type of plant is not particularly limited, but the light emitting device can activate the photosynthesis of the plant and emit light that is easily absorbed by the photoreceptor of the plant that forms photomorphogenesis, and can produce stems, leaves, roots, fruits, etc. Since it is possible to promote the growth of plants so as to have a good form or weight, it is preferable to apply it to the cultivation of vegetables, flowers and the like. Vegetables include leaf lettuce, garden lettuce, curl lettuce, lamb's lettuce, romaine lettuce, endive, lororossa, ruccola lettuce, frill lettuce, green leaf, lettuce such as sanchu, Asteraceae vegetables such as spring chrysanthemum, and Asagao vegetables such as spinach. , Vegetables of the family Asteraceae such as lettuce, and flowers such as lettuce, gerbera, lettuce, and lettuce.

Hereinafter, the present invention will be specifically described with reference to Examples. The present invention is not limited to these examples.

Examples 1 to 5 and Comparative Example 1
_{First Fluorescent Material As the first phosphor, it may be described as CaAlSiN 3} : Eu (hereinafter, “670CASN”) which is excited by light from a light emitting element having an emission peak wavelength at 450 nm and has an emission peak wavelength at 670 nm. ) Was used.

Second Fluorescent As the second fluorescent material, a fluorescent material obtained by the following production method was used.
As raw materials, Y ₂ O ₃ , CeO ₂ , Cr ₂ O ₃ , and Al ₂ O ₃ were used and weighed so as to have a desired charged composition ratio, with respect to 100 parts by mass of the total amount of each raw material containing no flux. , 5 parts by mass of BaF ₂ was added as a flux, and the mixture was dry-mixed by a ball mill for 1 hour to obtain a raw material mixture. The obtained raw material mixture was filled in an alumina crucible, covered, H ₂ is 3 vol%, a reducing atmosphere of N ₂ 97 vol%, 1500 ° C., by heat treatment for 10 hours to obtain a fired product .. This fired product was passed through a dry sieve to obtain a second phosphor. The obtained second phosphor was subjected to composition analysis by an ICP-AES emission spectrometry method using an inductively coupled plasma emission spectrometer (manufactured by Perkin Elmer). The composition of the obtained second phosphor was (Y _0.977 Ce _0.009 Cr _0.014 ) ₃ Al ₅ O ₁₂ (hereinafter, may be referred to as “YAG: Ce, Cr”). rice field. This second phosphor is excited by light from a light emitting device having an emission peak wavelength of 450 nm and has an emission peak wavelength of 707 nm.

Light emitting device A light emitting device was manufactured in the same manner as the light emitting device shown in FIG.
The light emitting device 100 uses a nitride semiconductor having a light emitting peak wavelength of 450 nm as the light emitting element 10.
A silicone resin is used as the resin constituting the fluorescent member 50, and the first fluorescent substance 71 or the second fluorescent substance 72 is added to 100 parts by mass of the silicone resin at the blending ratio (parts by mass) shown in Table 1, and then mixed and dispersed. , A resin composition constituting a fluorescent member was obtained by defoaming. In each of the resin compositions of Examples 1 to 5, as shown in Table 1, the compounding ratio (part by mass) of the first fluorescent substance 71 and the second fluorescent substance 72 was adjusted. This resin composition is injected onto the light emitting element 10 of the concave portion of the molded body 40, filled in the concave portion, and further heated at 150 ° C. for 4 hours to cure the resin composition to form the fluorescent member 50. A light emitting device 100 as shown in FIG. 1 was manufactured for each of Examples 1 to 5. In Comparative Example 1, a light emitting device was manufactured by using a resin composition containing only the first fluorescent substance 71 in the fluorescent member 50 without using the second fluorescent substance. In the obtained light emitting device, the mass ratio (mass%) of the first phosphor 71 and the mass ratio (mass%) of the second phosphor 72 to the total amount of 100% by mass of the first phosphor 71 and the second phosphor 72. ) Is shown in Table 1.

Examples 6 to 10 and Comparative Example 2
_{In Examples 6 to 10 and Comparative Example 2, CaAlSiN 3} : Eu (hereinafter, “660CASN”), which is excited by light from a light emitting device having an emission peak wavelength at 450 nm and has an emission peak wavelength at 660 nm, is used as the first phosphor. May be described.) Was used. In Examples 6 to 10, the same as in Example 1 except that the first fluorescent substance and the same second fluorescent substance as in Example 1 were used in the compounding ratio (part by mass) shown in Table 2. , Manufactured a light emitting device. In Comparative Example 2, a light emitting device was manufactured in the same manner as in Example 1 except that the resin composition containing only the first fluorescent substance was used without using the second fluorescent substance. In Table 2, in each of the resin compositions of Examples 6 to 10 and Comparative Example 2, the total amount (parts by mass) of the first fluorescent substance and the second fluorescent substance and the compounding of the first fluorescent substance with respect to 100 parts by mass of the resin. The ratio (part by mass) and the compounding ratio (part by mass) of the second phosphor are shown. Further, Table 2 shows the mass ratio (mass%) of the first phosphor to 100% by mass of the total amount of the first phosphor and the second phosphor in the light emitting devices of Examples 6 to 10 and Comparative Example 2. The mass ratio (mass%) of the second phosphor is shown.

Examples 11 to 15 and Comparative Example 3
_{Examples 11 to 15 and Comparative Example 3 have (Sr, Ca) AlSiN 3} : Eu (Sr, Ca) as the first phosphor, which is excited by light from a light emitting element having a emission peak wavelength of 450 nm and has an emission peak wavelength of 640 nm. Hereinafter, it may be described as “640SCASN”). In Examples 11 to 15, the same as in Example 1 except that the first fluorescent substance and the same second fluorescent substance as in Example 1 were used in the compounding ratio (part by mass) shown in Table 3. , Manufactured a light emitting device. In Comparative Example 3, a light emitting device was manufactured in the same manner as in Example 1 except that the resin composition containing only the first fluorescent substance was used without using the second fluorescent substance. In Table 3, in each of the resin compositions of Examples 11 to 15 and Comparative Example 3, the total amount (parts by mass) of the first fluorescent substance and the second fluorescent substance with respect to 100 parts by mass of the resin and the compounding ratio of the first fluorescent substance are shown. (Mass part) and the compounding ratio of the second phosphor (part by mass) are shown. Further, Table 3 shows the mass ratio (mass%) of the first phosphor to 100% by mass of the total amount of the first phosphor and the second phosphor in the light emitting devices of Examples 11 to 15 and Comparative Example 3. The mass ratio (mass%) of the phosphor is shown.

Examples 16 to 20
_{Examples 16 to 20 use (Sr, Ca) AlSiN 3} : Eu, which is excited by light from a light emitting element having a emission peak wavelength at 450 nm and has an emission peak wavelength at 640 nm, as the first phosphor. _{As the phosphor, 2} O _{3 (Al 0.9943} Cr _0.0057 ), which is excited by light from a light emitting element having an emission peak wavelength at 450 nm and has an emission peak wavelength at 692 nm, was used. A light emitting device is manufactured in the same manner as in Example 1 except that the first fluorescent substance and the second fluorescent substance are used in the compounding ratio (part by mass) shown in Table 4 in Examples 16 to 20. bottom. In Table 4, in each of the resin compositions of Examples 16 to 20, the total amount of the first fluorescent substance and the second fluorescent substance (parts by mass) and the compounding ratio of the first fluorescent substance (parts by mass) with respect to 100 parts by mass of the resin are shown. ) And the compounding ratio (parts by mass) of the second phosphor. Further, Table 4 shows the mass ratio (%) of the first fluorescent substance to 100% by mass of the total amount of the first fluorescent substance and the second fluorescent substance in the light emitting devices of Examples 16 to 20, and the mass ratio (%) of the second fluorescent substance. The mass ratio (%) is shown. Table 4 also shows the compounding ratio (mass part) of each fluorescent substance to 100 parts by mass of the resin in the resin composition of Comparative Example 3 and the mass ratio (mass%) of each fluorescent substance in the light emitting device of Comparative Example 3. bottom.

Examples 21 to 23
_{First Fluorescent As the first phosphor, AlSiN 3} : Eu, which is excited by light from a light emitting element having a emission peak wavelength at 450 nm and has an emission peak wavelength at 640 nm, was used.

Second Fluorescent As the second fluorescent material, a fluorescent material obtained by the following production method was used.
First, Lu ₂ O ₃ , CeO ₂ , Cr ₂ O ₃ , and Al ₂ O ₃ are used as raw materials, weighed so as to have a desired charged composition ratio, and the total amount of each raw material containing no flux is 100 mass. 5 parts by mass of BaF ₂ was added to each part as a flux, and the mixture was dry-mixed with a ball mill for 1 hour to obtain a raw material mixture. The obtained raw material mixture was filled in an alumina crucible, covered, H ₂ is 3 vol%, a reducing atmosphere of N ₂ 97 vol%, 1500 ° C., by heat treatment for 10 hours to obtain a fired product .. This fired product was passed through a dry sieve to obtain a second phosphor. The obtained second phosphor was subjected to composition analysis by an ICP-AES emission spectrometry method using an inductively coupled plasma emission spectrometer (manufactured by Perkin Elmer). The composition of the obtained second phosphor was (Lu _0.9725 Ce _0.0175 Cr _0.01 ) ₃ Al ₅ O ₁₂ (hereinafter, may be referred to as “LAG: Ce, Cr”). rice field. This second phosphor is excited by light from a light emitting device having an emission peak wavelength of 450 nm and has an emission peak wavelength of 687 nm.

_{Light emitting devices Examples 21 to 23 use (Sr, Ca) AlSiN 3} : Eu as the first phosphor, which is excited by light from a light emitting element having a light emitting peak wavelength at 450 nm and has a light emitting peak wavelength at 640 nm. As the second phosphor, LAG: Ce, Cr, which was excited by light from a light emitting element having an emission peak wavelength at 450 nm and had an emission peak wavelength at 687 nm, was used. In Examples 21 to 23, a light emitting device is manufactured in the same manner as in Example 1 except that the first fluorescent substance and the second fluorescent substance are used in the compounding ratio (part by mass) shown in Table 5. bottom. In Table 5, in each of the resin compositions of Examples 21 to 23, the total amount (parts by mass) of the first fluorescent substance and the second fluorescent substance and the compounding ratio of the first fluorescent substance (parts by mass) with respect to 100 parts by mass of the resin are shown. ) And the compounding ratio (parts by mass) of the second phosphor. Further, Table 5 shows the mass ratio (mass%) of the first phosphor to 100% by mass of the total of the first phosphor 71 and the second phosphor 72 in the light emitting devices of Examples 21 to 23, and the second fluorescence. Shows the mass ratio (mass%) of the body. Table 5 also shows the compounding ratio (mass part) of each fluorescent substance to 100 parts by mass of the resin in the resin composition of Comparative Example 3 and the mass ratio (mass%) of each fluorescent substance in the light emitting device of Comparative Example 3. bottom.

Examples 24 to 26
_{First Fluorescent As the first phosphor, AlSiN 3} : Eu, which is excited by light from a light emitting element having a emission peak wavelength at 450 nm and has an emission peak wavelength at 640 nm, was used.

Second Fluorescent As the second fluorescent material, a fluorescent material obtained by the following production method was used.
First, Gd ₂ O ₃ , CeO ₂ , Cr ₂ O ₃ , and Al ₂ O ₃ are used as raw materials, weighed so as to have a desired charged composition ratio, and the total amount of each raw material not containing flux is 100 mass. 5 parts by mass of BaF ₂ was added to each part as a flux, and the mixture was dry-mixed with a ball mill for 1 hour to obtain a raw material mixture. The obtained raw material mixture was filled in an alumina crucible, covered, H ₂ is 3 vol%, a reducing atmosphere of N ₂ 97 vol%, 1500 ° C., by heat treatment for 10 hours to obtain a fired product .. This fired product was passed through a dry sieve to obtain a second phosphor. The obtained second phosphor was subjected to composition analysis by an ICP-AES emission spectrometry method using an inductively coupled plasma emission spectrometer (manufactured by Perkin Elmer). The composition of the obtained second phosphor is (Gd _0.9675 Ce _0.0125 Cr _0.02 ) ₃ Al ₅ O ₁₂ (hereinafter, may be referred to as “GAG: Ce, Cr”). rice field. This second phosphor is excited by light from a light emitting device having an emission peak wavelength of 450 nm and has an emission peak wavelength of 727 nm.

_{Light emitting devices Examples 24 to 26 use (Sr, Ca) AlSiN 3} : Eu as the first phosphor, which is excited by light from a light emitting element having a light emitting peak wavelength at 450 nm and has a light emitting peak wavelength at 640 nm. As the second phosphor, GAG: Ce, Cr, which was excited by light from a light emitting element having an emission peak wavelength at 450 nm and had an emission peak wavelength at 727 nm, was used. In Examples 24 to 26, a light emitting device is manufactured in the same manner as in Example 1 except that the first fluorescent substance and the second fluorescent substance are used in the compounding ratio (part by mass) shown in Table 6. bottom. In Table 6, in each of the resin compositions of Examples 24 to 26, the total amount of the first fluorescent substance and the second fluorescent substance (parts by mass) and the compounding ratio of the first fluorescent substance (parts by mass) with respect to 100 parts by mass of the resin are shown. ) And the compounding ratio (parts by mass) of the second phosphor. Further, Table 6 shows the mass ratio (mass%) of the first phosphor and the mass ratio (mass%) of the second phosphor to the total amount of 100% by mass of the first phosphor and the second phosphor in the light emitting device. Is shown. Table 6 also shows the compounding ratio (mass part) of each fluorescent substance to 100 parts by mass of the resin in the resin composition of Comparative Example 3 and the mass ratio (mass%) of each fluorescent substance in the light emitting device of Comparative Example 3. bottom.

Relative photon flux The light emitted from the light emitting device according to each example and each comparative example was measured using a spectroscope (PMA-11, manufactured by Hamamatsu Photonics Co., Ltd.). The obtained radiant flux (W) was converted into a photon flux based on the following equation (1), and a spectrum of the photon flux was created. FIG. 2 shows the light emitting devices of Examples 1 to 5 and Comparative Example 1 as relative photon bundles with respect to the wavelength, with the spectrum of the photon flux at the wavelength of 670 nm of each light emitting device as 1. Further, FIG. 3 shows the light emitting devices of Examples 6 to 10 and Comparative Example 2 as relative photon bundles with respect to the wavelength, with the spectrum of the photon flux at the wavelength of 660 nm of each light emitting device as 1. Further, FIG. 4 shows the light emitting devices of Examples 11 to 15 and Comparative Example 3 as relative photon bundles with respect to the wavelength, with the spectrum of the photon flux at the wavelength of 640 nm of each light emitting device as 1. FIG. 5 shows the light emitting devices of Examples 16 to 20 and Comparative Example 3 as relative photon bundles with respect to the wavelength, with the spectrum of the photon flux at the wavelength of 640 nm of each light emitting device as 1. FIG. 6 shows the light emitting devices of Examples 21 to 23 and Comparative Example 3 as relative photon bundles with respect to the wavelength, with the spectrum of the photon flux at the wavelength of 640 nm of each light emitting device as 1. FIG. 7 shows the light emitting devices of Examples 24 to 26 and Comparative Example 3 as relative photon bundles with respect to the wavelength, with the spectrum of the photon flux at the wavelength of 640 nm of each light emitting device as 1.
Radiant flux (W) = Photon flux (mol · s ^-1 ) x Avogadro's number (mol ^-1 ) x Planck's constant (Js) x Speed of light (m · s ^-1 ) ÷ Wavelength (m) (1)

Photon flux For each example and comparative example, the photon flux in each wavelength range was calculated using the spectrum of the photon flux of the light emitting device obtained from the above equation (1). The photon bundle B of blue light was calculated by integrating the photon bundles in the wavelength range of 400 nm or more and 490 nm or less. Further, the photon bundle R of red light was calculated by integrating the photon bundles in the wavelength range of 620 nm or more and less than 700 nm. Further, the photon bundle Fr of far-red light was calculated by integrating the photon bundles in the wavelength range of 700 nm or more and 780 nm or less. From the photon bundles B, R, and F obtained for the light emitting devices of each Example and Comparative Example, the ratio R / B of the photon bundle R to the photon bundle B and the ratio R / Fr of the photon bundle R to the photon bundle Fr were obtained. The results are shown in Tables 1 to 6.

8 shows Examples 1 to 5, Comparative Example 1, Examples 6 to 10, Comparative Example 2, Examples 11 to 15, Comparative Example 3, Examples 16 to 20, Comparative Example 3, and Examples 21 to 23. The ratio R / Fr of the content of the second phosphor in the fluorescent member provided in each of the light emitting devices of Comparative Examples 3, 24 to 26 and Comparative Example 3 and the photon bundle R to the photon bundle Fr of each light emitting device. It is a graph which shows the relationship.

As shown in Tables 1 to 6, in the light emitting devices of Examples 1 to 26, the ratio R / B of the photon bundle of red light to the photon bundle B of blue light is more than 10 and 12 or less, and is of far red light. The ratio R / Fr of the photon bundle R of red light to the photon bundle Fr was 1.59 or more and 4.12 or less.
As shown in FIGS. 2 to 7, the light emitting device including the first phosphor and the second phosphor is excited by the emission peak wavelength of the light emitting element at 450 nm and the light from the light emitting element and has a wavelength of 580 nm or more and less than 680 nm. It has at least one emission peak wavelength of the first phosphor within the wavelength range, and is excited by the light from the light emitting element to have at least one emission peak wavelength of the second phosphor within the wavelength range of 680 nm or more and 800 nm or less. It was confirmed that it had.

As shown in Tables 1 to 6, the light emitting devices of Comparative Examples 1 to 3 had a ratio R / B of the photon bundle R to the photon bundle B of 10 or more, but the light emitting devices of Comparative Examples 1 to 3 had. Since the fluorescent member containing the second phosphor is not provided, the ratio R / Fr of the light emitting device of Comparative Example 1 is larger than the ratio R / Fr of each light emitting device of Examples 1 to 5, and the ratio R / Fr of Comparative Example 2 The ratio R / Fr of the light emitting device is larger than the ratio R / Fr of each light emitting device of Examples 6 to 10, and the ratio R / Fr of the light emitting device of Comparative Example 3 is the ratio R / Fr of each light emitting device of Examples 11 to 26. It is difficult to control the mixed-color light having a smaller ratio R / Fr, which is larger than the ratio R / Fr and is easily absorbed by the photon receptors of the plant and promotes the formation of light morphology of the plant. rice field.

Further, as shown in FIGS. 2 to 7, since each of the light emitting devices of Comparative Examples 1 to 3 does not include a fluorescent member including a second phosphor, it is excited by light from a light emitting element having a light emitting peak wavelength of 450 nm. However, the presence of at least one emission peak wavelength was not observed in the wavelength range of 680 nm or more and 800 nm or less.

As shown in FIG. 8, in the light emitting devices of Examples 1 to 26, the ratio R / Fr of the photon bundle R of red light to the photon bundle Fr of far red light is adjusted by the amount of the second phosphor contained in the fluorescent member. I was able to confirm that it was possible. As described in Non-Patent Document 1 shown in FIG. 11, it is shown that the difference in the spectral distribution of the light source affects, for example, the plant height of romaine lettuce, and that the plant height of romaine lettuce decreases when the ratio R / Fr is small. There is. As shown in FIG. 8, as in the light emitting devices of Examples 1 to 26, the ratio R / B of the optical quantum bundle R of red light to the optical quantum bundle B of blue light and the ratio of the optical quantum bundle R to the optical quantum bundle Fr. When the plant can be irradiated with mixed-color light with controlled R / Fr, the photoreceptors of the plant that form the light morphology, such as red light absorption type (Pr type) phytochrome and far red light absorption type (Pfr) phytochrome, It is possible to irradiate the two photoreceivers with light that is easily absorbed, promote the light formation morphology of the plant, and irradiate the light that further promotes the growth of the plant.

Next, a light emitting device used as a light source for plant cultivation was manufactured by combining the light emitting device of the above-mentioned Example or Comparative Example with a white LED which is a light source for emitting white light. Hereinafter, the light emitting device in which the light emitting device of the example or the comparative example and the white LED are combined is referred to as a light source for plant cultivation.

Light source for plant cultivation A
A light source A for plant cultivation was manufactured by combining the light emitting device of Comparative Example 2 and the white LED.

Light source for plant cultivation B
The light source B for plant cultivation was manufactured by combining the light emitting device of Example 8 and the white LED.

Light source for plant cultivation C
The light source C for plant cultivation was manufactured by combining the light emitting device of Example 9 and the white LED.

Light source for plant cultivation D
The light source D for plant cultivation was manufactured by combining the light emitting device of Example 10 and the white LED.

Photon bundle The spectrum of the photon bundle of light emitted from light sources A to D for plant cultivation was measured using a spectroscopic radiation illuminance meter (CL-500A, manufactured by Konica Minolta Co., Ltd.), and the photon bundle in the wavelength range of 400 nm or more and 490 nm or less. The optical quantum bundle B of blue light integrated with, the optical quantum bundle R of red light integrated with the optical quantum bundle in the wavelength range of 620 nm or more and less than 700 nm, and the optical quantum of far-red light integrated with the optical quantum bundle of the wavelength range of 700 nm or more and 780 nm or less. The bundle Fr was calculated, and the ratio R / B of the optical quantum bundle R of red light to the optical quantum bundle B of blue light and the ratio R / Fr of the optical quantum bundle R of red light to the optical quantum bundle Fr of far-red light were obtained. The results are shown in Table 7. FIG. 9 shows the spectrum of the photon flux with respect to the wavelengths of the light sources A to D for plant cultivation. In FIG. 9, the emission peak wavelength in the wavelength range of 380 nm or more and 490 nm or less of the light sources A to D for plant cultivation is set as 1, and is represented as a spectrum of photon flux relative to the wavelength.

Plant cultivation test Lettuce was used as a plant for cultivation.
Seeding Plant seeds were sown on a urethane sponge (manufactured by Tokuyama Seisakusho Co., Ltd., a flat type general-purpose product) and irradiated with light from a white LED (manufactured by Nichia Corporation) to germinate and raise seedlings.
The plant was used for 7 days under the conditions of room temperature of 25 ° C., humidity of 60%, CO ₂ concentration of 800 to 1100 ppm, photon flux density of white LED of 80 μmol · m- ² · s ^{-1, and day length of 16 hours / day.} Cultivated.
The size of the third leaf of lettuce was measured 7 days after planting and sowing, and a plant of the same size was used for the test. The reason for using lettuce with the same size of the third leaf is to suppress the variation due to seeds as much as possible and to clarify the difference in plant growth due to the influence of the light emitted from the light source, which is the original purpose. be.
The plants selected for the test were irradiated with the light of the light sources A to D for plant cultivation, and the plants were hydroponically cultivated. Room temperature is 25 ° C, humidity is 60%, CO ₂ concentration is 800 to 1100 ppm, photon flux density of cultivation light sources A to D is 310 μmol · m ^-2 · s ^-1 , and day length is 16 hours / day for 25 days. , Cultivated plants. The nutrient solution is a mixture of NS1 (manufactured by OAT Agrio Co., Ltd.) and NS2 (manufactured by OAT Agrio Co., Ltd.) at a mass ratio (NS1: NS2) of 2: 3 dissolved in water. used. The conductivity of the nutrient solution was 2.0 mS · cm ^-1 . The ratio R / B of the photon bundle of red light to the photon bundle B of blue light of the light sources A to D for cultivation and the ratio R / Fr of the photon bundle R of red light to the photon bundle Fr of far-red light are the planting period. Did not change through.

Measurement of fresh weight (edible part) The plant after cultivation was harvested, the roots were removed from the harvested plant, and the wet weight of the above-ground part of the plant was measured. Light from light sources A to D for plant cultivation is applied to 6 plants for hydroponics, and the wet weight of the above-ground part of each hydroponically cultivated plant is fresh weight (edible part) (g). Measured as. The average value of the fresh weight (edible portion) (g) of the six plants is shown in Table 7.

Measurement of plant height Each of the 6 plants is irradiated with light from light sources A to D for hydroponics, hydroponically cultivated, each plant is harvested, and the longest leaf from the root of each harvested plant. The length up to the tip was measured as the plant height (cm). The average value of plant height (cm) of 6 plants is shown in Table 7.

As shown in Table 7, the light sources B to D for plant cultivation using the light emitting devices of Examples 8, 9 and 10 and the white LED are the light source A for plant cultivation using the light emitting device of Comparative Example 2 and the white LED. In comparison, the fresh weight (edible part) increased and the plant height also increased. From this result, the light emitting device according to the first embodiment of the present invention can be used in combination with a light source that emits white light to photosynthesize plants, extend stems, expand leaves, and the like. It was confirmed that light that is easily absorbed by the photoreceptors of plants that form photomorphogenesis can be emitted and that the growth of plants can be promoted.

As shown in FIG. 9, in the light sources B to D for plant cultivation using the light emitting device of Examples 8, 9 or 10 and the white LED, the ratio R / of the photosynthetic bundle R of red light to the photosynthetic bundle Fr of far red light. The Fr is smaller than the light source A for plant cultivation using the light emitting device of Comparative Example 2 and the white LED, and the Fr component is increased, so that the synergistic effect (Emmerson effect) of the two types of light, far-red light and red light, is achieved. ) Also, it is presumed that photosynthesis was activated and the growth of plants was promoted.

Next, as a reference example, CaAlSiN having an emission peak wavelength at 660 nm excited by light from a light emitting element having an emission peak wavelength at 450 nm used as the first phosphor in Comparative Example 2 and Examples 8 to 10 described above. ₃ : The relationship between Eu (660CASN) and the temperature and peak wavelength of a red LED having an emission peak wavelength near 660 nm was measured. Specifically, at 25 ° C., 105 ° C., and 140 ° C., the 660CASN phosphor is irradiated with light from a light emitting element having an emission peak wavelength of 450 nm, and the spectrum of the light emitted from the 660CASN phosphor is obtained by using a spectroscope. The measurement was performed, and the peak wavelength of the emission spectrum at each temperature was determined. Further, the spectrum of the light emitted from the red LED was measured at 25 ° C., 85 ° C., and 120 ° C. using the spectroscope, and the peak wavelength of the spectrum at each temperature was determined. The results are shown in Table 8 and FIG.

As shown in Table 8 and FIG. 10, the 660CASN used as the first phosphor in the light emitting devices of Examples 6 to 10 has a peak wavelength even when used at a high temperature of about 25 ° C to 140 ° C, which is about room temperature. The fluctuation is small. When the red LED was used at 25 ° C. and at a high temperature of 120 ° C., the peak wavelength fluctuated greatly toward the long wavelength side as it was used at a higher temperature. From this result, in the red LED, the peak wavelength changes depending on the temperature, and it is difficult to adjust the optical quantum bundle of red light. Even when the ratio R / Fr of the photon flux R of red light to Fr is adjusted, the ratio R / B and the ratio R / Fr may fluctuate depending on the temperature, and the growth of the plant may become unstable. It turned out that there was.

The light emitting device of one aspect of the present invention can emit light that is easily absorbed by the photoreceptors of plants that form photomorphogenesis, promote the formation of photomorphogenesis of plants, and further promote the growth of plants for plant cultivation. It can be used as a light emitting device or a lighting device. The light emitting device of one aspect of the present invention is used as a light emitting device for supplementary light that promotes the growth of plants by using it in combination with a light source that emits white light or a light source that emits light energy different from the light emitting device. be able to.

10: light emitting element, 40: molded body, 50: fluorescent member, 71: first fluorescent body, 72: second fluorescent body, 100: light emitting device.

Claims (10)

A light emitting device having a emission peak wavelength within the wavelength range of 380 nm or more and 490 nm or less,
A first phosphor that is excited by light from the light emitting device and emits light having at least one emission peak wavelength within a wavelength range of 580 nm or more and less than 680 nm.
A second phosphor that is excited by light from the light emitting element and emits light having at least one emission peak wavelength within a wavelength range of 680 nm or more and 800 nm or less is provided.
The ratio R / B of the photon bundle R of red light in the wavelength range of 620 nm or more and less than 700 nm to the photon bundle B of blue light in the wavelength range of 400 nm or more and 490 nm is more than 10 and 38 or less.
The ratio R / Fr of the photon bundle R to the photon bundle Fr of far-red light in the wavelength range of 700 nm or more and 780 nm or less is 1.5 or more and 2.61 or less.
The mass ratio of the second phosphor to the total amount of the first phosphor and the second phosphor is 2% by mass or more and 75% by mass or less.
The second phosphor comprises a first aluminate phosphor having a composition represented by the following formula (I) and a second aluminate phosphor having a composition represented by the following formula (II). A light emitting device for growing lettuce containing at least one fluorescent substance selected from the group and containing santu.
(Al _1-w Cr _w ) ₂ O ₃ (I)
(In formula (I), w is a number satisfying 0 <w <1.)
_{(Ln 1-x-y Ce} x Cr y) 3 (Al 1-z M z) 5 O 12 (II)
(In formula (II), Ln is at least one rare earth element selected from the group consisting of rare earth elements excluding Ce, and M is at least one element selected from the group consisting of Ga and In. x, y and z are numbers that satisfy 0.0002 <x <0.50, 0.0001 <y <0.05, 0≤z≤0.8). The light emitting device according to claim 1, wherein the first phosphor comprises a nitride phosphor having a composition containing at least one element selected from Sr and Ca, Eu, Al, and Si. The light emitting device according to claim 2, wherein the first phosphor contains a nitride phosphor having a composition represented by the following formula (III).
(Ca _1-p-q Sr _p Eu _q ) AlSiN ₃ (III)
(In formula (III), p and q are numbers satisfying 0 ≦ p ≦ 1.0, 0 <q <0.5, 0 <p + q ≦ 1.0). ^{Eu 2+} activated aluminum nitride having a composition of at least one element selected from the group consisting of alkaline earth metal elements and at least one element selected from the group consisting of alkaline metal elements. phosphor, Mn ⁴⁺ activated fluoro jar money preparative phosphor, Eu ²⁺ activated alkaline earth sulfide phosphors, and further comprising at least one first phosphor is selected from the group consisting of Mn ⁴⁺ activated fluoride phosphor, the light emitting device according to any one of claims 1 or et 3. First phosphor further comprises at least one phosphor selected from the group consisting of a phosphor having any composition represented by the following formula (IV) to (VIII), according to claim 1 or et 4 The light emitting device according to any one of the following items.
(I-j) MgO · (j / 2) Sc ₂ O ₃ · kmgF ₂ · mCaF ₂ · (1-n) GeO ₂ · (n / 2) M ¹ O ₃ : vMn ⁴⁺ (IV)
(In formula (IV), M ¹ is at least one selected from the group consisting of Al, Ga and In, and i, j, k, m, n and v are 2 ≦ i ≦ 4, 0 ≦ j, respectively. <0.5, 0 <k <1.5, 0 ≦ m <1.5, 0 <n <0.5, and 0 <v <0.05.)
M ² _d M ³ _e M ⁴ _f Al _3-g Si _g N _h (V)
(In formula (V), M ² is at least one element selected from the group consisting of Ca, Sr, Ba and Mg, and M ³ is at least one selected from the group consisting of Li, Na and K. M ⁴ is at least one element selected from the group consisting of Eu, Ce, Tb and Mn, and d, e, f, g and h are 0.80 ≦ d ≦ 1. 05, 0.80 ≦ e ≦ 1.05, 0.001 <f ≦ 0.1, 0 ≦ g ≦ 0.5, 3.0 ≦ h ≦ 5.0.)
(Ca _1-r-s-t Sr _r Ba _s Eu _t ) ₂ Si ₅ N ₈ (VI)
(In the formula (VI), r, s and t are numbers satisfying 0 ≦ r ≦ 1.0, 0 ≦ s ≦ 1.0, 0 <t <1.0 and r + s + t ≦ 1.0).
(Ca, Sr) S: Eu (VII)
A ₂ [M ⁵ _1-u Mn ^{4 +} _u F ₆ ] (VIII)
(In the formula (VIII), A is, K, is at least one Li, Na, Rb, are chosen from Cs, and the group consisting of _NH ^{4 +, M 5} consists of an element of Group 4 and Group 14 elements It is at least one element selected from the group, and u is a number satisfying 0 <u <0.2.) A fluorescent member containing the first fluorescent substance, the second fluorescent substance, and a resin is provided, and the fluorescent member comprises 0.5 parts by mass or more of the second fluorescent substance with respect to 100 parts by mass of the resin. parts by weight formed by containing the following, the light emitting device according to any one of claims 1, 4, and 5. A fluorescent member containing the first fluorescent substance, the second fluorescent substance, and a resin is provided, and the fluorescent member comprises 0.5 parts by mass or more of the second fluorescent substance with respect to 100 parts by mass of the resin. parts by weight formed by containing the following, the light emitting device according to any one of claims 1, 4, and 5. The sixth or seventh aspect of the present invention, wherein the fluorescent member contains 5 parts by mass or more and 150 parts by mass or less of the total amount of the first fluorescent substance and the second fluorescent substance with respect to 100 parts by mass of the resin. Light emitting device. The light emitting device according to claim 7, wherein the fluorescent member contains 5 parts by mass or more and 83 parts by mass or less of the total amount of the first fluorescent substance and the second fluorescent substance with respect to 100 parts by mass of the resin. .. CO 2 _and, in the presence of humidity or water, irradiated with light emitted from the light emitting device according to any one of claims 1 9 in lettuce containing lettuce, plant cultivation method.

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