Light emitting device and plant cultivation method

Abstract

The present invention provides a light-emitting device and a plant cultivation method capable of promoting plant growth. A light-emitting device comprises: a light-emitting element having a peak emission wavelength in the range of 380 nm to 490 nm; and a red phosphor that is excited by light from the light-emitting element and emits light having at least one peak emission wavelength in the range of 580 nm to 680 nm, wherein the ratio (R / B) of the photon flux R of red light in the range of 620 nm to 700 nm to the photon flux B of blue light in the range of 400 nm to 490 nm is greater than 20 and less than 200.

Description

Technical Field

[0001] The invention relates to a light emitting device and a plant cultivation method. Background Art

[0002] Amid environmental changes caused by climate change / human environmental destruction, it is expected to provide a stable supply of plants such as vegetables and improve plant production efficiency. For example, a plant factory that can be managed manually can stably supply clean and safe vegetables to the market, and is therefore highly anticipated as a next-generation industry. In plant factories, in order to reduce power consumption and effectively cultivate plants, light-emitting diodes (Light Emitting Diode: hereinafter referred to as "LED") are used. LEDs can control the combination and intensity of light wavelengths and can irradiate light that matches the growth rate and morphogenesis of plants. Therefore, they are highly anticipated as a light source for promoting plant growth and for cultivating plants with rich functional nutrients and high added value.

[0003] The reaction of plants to light can be divided into photosynthesis and photomorphogenesis. Photosynthesis is a reaction that uses light energy to decompose water, generate oxygen and fix carbon dioxide to organic matter. As a result of photosynthesis, the carbohydrates generated become the raw materials for building plant cells and become the energy source for plant growth. Photomorphogenesis is a morphological reaction that uses light as a signal to carry out seed germination, differentiation (germination formation, leaf formation, etc.), movement (stomatal opening and closing, chloroplast movement), light refraction, etc. There are multiple light receptors (pigments) in plants that recognize light. In the case of photosynthesis, chlorophyll a, chlorophyll b, and carotenoids capture light in the form of energy. In the case of photomorphogenesis, plant phytochromes, cryptochromes, and phototropins receive light in the form of signals.

[0004] The wavelength range of light that plants can use photoreceptors for photosynthesis and photomorphogenesis is 300 nm to 800 nm. The radiation in this wavelength range is called physiologically active radiation, and the radiation in the wavelength range of 400 nm to 700 nm, which is the energy source for plant cultivation, is called photosynthetically active radiation. The light intensity necessary for photosynthesis of plants is sometimes expressed as photosynthetic photon flux density or photosynthetic photon flux (Photosynthetic Photon Flux, hereinafter sometimes also expressed as "PPF").

[0005] The intensity of light irradiating plants and the like is expressed as photon flux density or photon flux (hereinafter sometimes referred to as "PF"). Photon flux density (μmol·m -2 ·s -1 ) refers to the number of photons reaching a unit area per unit time. Photon flux (μmol·s -1 ) refers to the number of photons per unit time. The ratio (R / B) of the photon flux B in the blue region recognized by the photoreceptor to the photon flux R in the red region needs to be controlled according to the growth of the plant. Therefore, a light-emitting device combining a blue-light-emitting LED chip and a phosphor that absorbs the blue light emitted by the LED chip and emits light that is more red than blue has been proposed (see Patent Document 1). In addition, a method of supplementing red light by combining a red-light-emitting phosphor with an existing light source that emits white light has also been proposed (see Patent Document 2).

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2013-099254

[0009] Patent Document 2: Japanese Patent Application Publication No. 2008-181771 Summary of the invention

[0010] Problems to be solved by the invention

[0011] However, in the light-emitting device disclosed in Patent Document 1, when it is combined with an existing light source that emits white light and used for fill light purposes, as described in detail later, there is a tendency that the spectral balance of the light emitted by the existing light source is destroyed, and in the spectrum of the light emitted by the existing light source, the green light in the range of greater than 490nm and less than 570nm and the yellow to orange light in the range of greater than 570nm and less than 620nm are reduced.

[0012] Therefore, an object of one aspect of the present invention is to provide a light emitting device and a plant cultivation method that can supplement red light without destroying the spectral balance of light emitted by the existing light source when used together with the existing light source.

[0013] Methods for solving problems

[0014] Means for solving the above-mentioned problems are as follows, and the present invention includes the following means.

[0015] A first aspect of the present invention is a light emitting device comprising:

[0016] A light-emitting element having a peak emission wavelength in the range of 380 nm to 490 nm; and

[0017] a red phosphor that is excited by the light from the light emitting element and emits light having at least one emission peak wavelength in the range of 580 nm to 680 nm,

[0018] The ratio (R / B) of the photon flux R of red light in the range of greater than 620nm and less than 700nm to the photon flux B of blue light in the range of greater than 400nm and less than 490nm (hereinafter, the ratio of the photon flux R of red light in the range of greater than 620nm and less than 700nm to the photon flux B of blue light in the range of greater than 400nm and less than 490nm is sometimes referred to as the "R / B ratio") is greater than 20 and is less than 200.

[0019] A second aspect of the present invention is a lighting device that combines the above-mentioned light-emitting device with a light source that emits light energy different from that of the light-emitting device.

[0020] A third aspect of the present invention is a plant cultivation method, wherein the light emitted from the light emitting device is irradiated onto the plant.

[0021] Effects of the Invention

[0022] According to the present invention, a light emitting device and a plant cultivation method can be provided which can supplement red light without destroying the spectral balance of light emitted by the existing light source and can promote plant growth when used together with the existing light source. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic cross-sectional view showing an example of a light emitting device.

[0024] Figure 2 It is a graph showing the relationship between the photon flux B (Blue PF) of blue light, the photon flux R (Red PF) of red light, and the photosynthetic photon flux PPF with respect to the R / B ratio of the light-emitting device for red fill light of each embodiment and comparative example.

[0025] Figure 3 It is a graph showing the relationship between the photosynthetic photon flux PPF of mixed light obtained by combining the white LED light-emitting device 1 with the red fill light light-emitting device of each embodiment and comparative example, and the number ratio (%) of the white LED light-emitting device 1 when the white LED light-emitting device is combined with the red fill light light-emitting device of each embodiment and comparative example.

[0026] Figure 4The spectrum represents the relative photon flux of light emitted by the white LED light-emitting device 1 alone, the spectrum of the relative photon flux of mixed light obtained by combining the white LED light-emitting device 1 with the red fill light light-emitting device of Example 1, and the spectrum of the relative photon flux of mixed light obtained by combining the white LED light-emitting device 1 with the red fill light light-emitting device of Comparative Example 2.

[0027] Figure 5 The spectrum represents the relative photon flux of light emitted by the white LED light-emitting device 1 alone, the spectrum of the relative photon flux of mixed light obtained by combining the white LED light-emitting device 1 with the red fill light light-emitting device of Example 2, and the spectrum of the relative photon flux of mixed light obtained by combining the white LED light-emitting device 1 with the red fill light light-emitting device of Comparative Example 2. DETAILED DESCRIPTION

[0028] Hereinafter, an embodiment of the light-emitting device and the plant cultivation method according to the present application will be described. Among them, the embodiment shown below is an illustration for describing the technical idea of ​​the present invention in detail, and the present invention is not limited to the following light-emitting device and plant cultivation method. It should be noted that the relationship between the color name and the chromaticity coordinate, the relationship between the wavelength range of light and the color name of a single light, etc. are based on JIS Z8110. In addition, regarding the content of each component in the composition, when there are multiple substances that meet the requirements of each component in the composition, unless otherwise specified, it refers to the total amount of the multiple substances present in the composition.

[0029] Light-emitting device

[0030] One embodiment of the present invention is a light-emitting device comprising: a light-emitting element having a peak emission wavelength in a range of 380 nm to 490 nm (hereinafter sometimes referred to as a "near ultraviolet to blue region"); and a red phosphor that is excited by light from the light-emitting element and emits light having at least one peak emission wavelength in a range of 580 nm to 680 nm, wherein the ratio R / B of a photon flux R of red light in a range of 620 nm to 700 nm relative to a photon flux B of blue light in a range of 400 nm to 490 nm is greater than 20 and less than 200. In this specification, the photon flux B of blue light in a range of 400 nm to 490 nm may be referred to as "photon flux B of blue light". In addition, in this specification, the photon flux R of red light in a range of 620 nm to 700 nm may be referred to as "photon flux R of red light".

[0031] An example of a light emitting device according to an embodiment of the present invention will be described with reference to the drawings. Figure 1 1 is a schematic cross-sectional view showing a light emitting device 100 according to an embodiment of the present invention.

[0032] The light emitting device 100 is as follows Figure 1 As shown, the light-emitting device 100 comprises: a light-emitting element 10 having a peak emission wavelength in the range of 380 nm to 490 nm; and a red phosphor 70 which is excited by light from the light-emitting element and emits light having at least one peak emission wavelength in the range of 580 nm to 680 nm.

[0033] The light emitting device 100 includes, for example, a molded body 40, a light emitting element 10, and a fluorescent component 50. The molded body 40 is formed integrally with a resin portion 42 including a first lead 20 and a second lead 30 and a thermoplastic resin or a thermosetting resin. The molded body 40 forms a recess having a bottom surface and a side surface, and the light emitting element 10 is placed 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 via a lead 60, respectively. The light emitting element 10 is covered by the fluorescent component 50. The fluorescent component 50 includes, for example, a fluorescent body 70 for converting the wavelength of light from the light emitting element 10 and a sealing material. The fluorescent body 70 is a red fluorescent body 70 that emits red light due to the light from the light emitting element 10 having a peak emission wavelength in the range of 380 nm to 490 nm emitted by the light emitting element 10. The first lead 20 and the second lead 30 connected to the positive and negative electrodes of the light emitting element 10 are partially exposed to the outside of the package constituting the light emitting device 100. Through these first lead 20 and the second lead 30, the light emitting device 100 can receive power from the outside to emit light.

[0034] The fluorescent member 50 not only converts the wavelength of light emitted by the light emitting element 10, but also functions as a member for protecting the light emitting element 10 from the external environment. Figure 1 In the embodiment, the red phosphor 70 is present in the fluorescent component 50 and is arranged close to the light emitting element 10. Thus, the red phosphor 70 can be used to efficiently convert the wavelength of light from the light emitting element 10, and a light emitting device with excellent light emitting efficiency can be provided. The arrangement of the fluorescent component 50 including the red phosphor 70 and the light emitting element 10 is not limited to Figure 1 In addition to the arrangement of the red phosphor 70 close to the light emitting element 10 as shown, the red phosphor 70 may be arranged in the fluorescent member 50 with a gap between it and the light emitting element 10, taking into account the influence of heat generated by the light emitting element 10. In addition, by arranging the red phosphor 70 substantially evenly in the fluorescent member 50, light with suppressed color unevenness can be emitted from the light emitting device 100.

[0035] Plants absorb light through the pigments (chlorophyll a, chlorophyll b and carotenoids) present in their chloroplasts, obtain carbon dioxide and water, and use photosynthesis to convert them into carbohydrates (sugars) for growth. Chlorophyll a and chlorophyll b used to promote plant cultivation have absorption peaks for light in the red region above 625nm and below 675nm and absorption peaks for light in the blue region above 425nm and below 475nm. Among the photoreceptors of plants, chlorophyll a captures light energy in the blue region above 400nm and below 450nm and light energy in the red region above 660nm and below 700nm for photosynthesis. Chlorophyll b captures light energy in the blue region above 430nm and below 500nm and light energy in the red region above 640nm and below 670nm for photosynthesis. Carotenoids capture light energy in the blue to green region above 400nm and below 530nm for photosynthesis. In addition, among the photoreceptors that perform photomorphogenesis, for example, phytochrome A uses light in the blue region of 360 nm to 480 nm as a signal to induce seed germination. In addition, phytochrome B uses light in the red region of 540 nm to 690 nm as a signal to induce seed germination, etc.

[0036] During their growth stage, plants not only perform photosynthesis, but also perform photomorphogenesis such as induction of germination from seeds, elongation of hypocotyls, formation of flower buds, and light refraction. Depending on the type and growth stage of the plant, it is effective to supplement not only white light represented by sunlight but also red light to promote plant growth and enhance the functional nutrients of the plant. It can be further known that green light exceeding 490nm and below 570nm, which was previously said to have little effect on plant growth, helps promote plant growth and enhance the functional nutrients of the plant depending on the type of plant, and affects the opening and closing of stomata and the elongation of hypocotyls of etiolated growth. In addition, as a working environment for people, light containing green light components in the range of exceeding 490nm and below 570nm and yellow to orange luminescent components in the range of exceeding 570nm and less than 620nm is also required. When supplementing red light, if the balance of the spectrum in the blue region and the spectrum in the green, yellow and orange regions of the existing light source, such as white light, is not significantly disrupted, a small number of light-emitting devices can be used to effectively supplement the red light. This can reduce power consumption and equipment investment costs, and effectively promote plant growth and cultivate plants rich in functional nutrients.

[0037] In the light-emitting device of one embodiment of the present invention, the R / B ratio of the photon flux R of red light in the range of 620 nm to 700 nm to the photon flux B of blue light in the range of 400 nm to 490 nm is greater than 20 and less than 200. If the R / B ratio of the photon flux R of red light to the photon flux B of blue light in the light-emitting device of one embodiment of the present invention is greater than 20 and less than 200, the range of the R / B ratio can be appropriately selected according to the type of plant or the growth stage of the plant. In the light-emitting device of one embodiment of the present invention, the R / B ratio of the photon flux R of red light to the photon flux B of blue light is preferably greater than 30 and less than 180, more preferably greater than 35 and less than 150, still more preferably greater than 40 and less than 140, greater than 50 and less than 120, or greater than 80 and less than 120. In a light-emitting device of one embodiment of the present invention, if the R / B ratio of the photon flux R of red light relative to the photon flux B of blue light is greater than 20 and less than 200, it is possible to utilize an existing white light source and, with the aid of a small number of light-emitting devices capable of supplementing red light, to effectively supplement red light according to the type of plant or the growth stage of the plant without disrupting the spectral balance of the existing light source, such as white light.

[0038] In a light-emitting device having a light-emitting element having a peak emission wavelength in the near-ultraviolet to blue region and a red phosphor, if the R / B ratio of the photon flux R of red light to the photon flux B of blue light is 20 or less, the excitation light emitted from the light-emitting element is not wavelength-converted by the red phosphor, and the blue light component that passes through the light-emitting device increases, and it is sometimes difficult to effectively supplement the desired red light. In addition, in the above-mentioned light-emitting device, if the R / B ratio of the photon flux R of red light to the photon flux B of blue light is 20 or less, the blue light that is the excitation light from the light-emitting element passes through, and the blue light component is supplied together with the red light. Therefore, when an existing light source that emits white light, for example, is used in combination with a light-emitting device that supplements red light, in the spectrum of light emitted by the existing light source, the green to yellow light components are relatively reduced due to the addition of the blue light component that passes through the light-emitting device for supplementing red light, and the spectral balance of the light emitted from the existing light source is destroyed, and it is sometimes impossible to supplement the red light purely. In addition, in the above-mentioned light-emitting device, if the R / B ratio of the red light photon flux R to the blue light photon flux B exceeds 200, the amount of red phosphor contained in the above-mentioned light-emitting device becomes excessive, and sometimes the red light is attenuated due to self-absorption of the phosphor.

[0039] The light emitting device of one embodiment of the present invention preferably has at least one luminescence peak in the range of 580 nm to 680 nm in the spectrum of light emitted from the light emitting device, and the half-value width of the luminescence peak is 40 nm or more. With respect to the light emitting device, in the spectrum of light emitted from the light emitting device, the half-value width of the luminescence peak in the range of 580 nm to 680 nm is more preferably 40 nm to 120 nm, further preferably 50 nm to 120 nm, and further preferably 60 nm to 110 nm. With respect to the light emitting device, in the spectrum of light emitted from the light emitting device, the half-value width of the luminescence peak in the red region of 580 nm to 680 nm is preferably 40 nm or more and has a relatively flat shape. In the spectrum of light emitted from the light emitting device, if the half-value width of the luminescence peak in the red region of 580 nm to 680 nm is wider, the photoreceptors of more plants can absorb the supplementary red light in the form of light energy, or can perceive it as a light signal. Regarding a light-emitting device according to an embodiment of the present invention, in the spectrum of light emitted from the above-mentioned light-emitting device, red light having a light-emitting peak with a relatively flat shape can be supplied, and a plurality of photoreceptors can easily absorb or sense the red light emitted from the above-mentioned light-emitting device, thereby promoting the growth of plants in a stable state, and enhancing the functional nutrients of plants in a stable state. The half-value width of a light-emitting device refers to: the full width at half maximum (Full Width at HalfMaximum: FWHM) of the light-emitting peak in the spectrum of light emitted by the light-emitting device. The half-value width of a light-emitting device refers to: in the spectrum of light emitted by the light-emitting device, the wavelength width of the light-emitting peak representing 50% of the maximum value of the light-emitting peak existing in the range above 580nm and below 680nm.

[0040] For example, in the case of a light-emitting device having a red-emitting LED chip, the half-value width of the emission peak existing in the range of 580 nm to 680 nm is usually less than 30 nm, and is usually 15 nm to 25 nm. In the spectrum of light emitted from a light-emitting device having a red-emitting LED chip, if the half-value width of the emission peak existing in the red region of 580 nm to 680 nm is less than 30 nm and presents a sharp shape, then depending on the above-mentioned light-emitting device, the types of photoreceptors of plants that absorb or sense the supplemented red light are limited, and sometimes the growth of the plants is unstable.

[0041] The light intensity that affects photosynthesis or photomorphogenesis in plants depends on the number of photons. The energy of a photon varies inversely with its wavelength. If Planck's constant (6.63×10 -34 Js) is denoted as h, and the speed of light is denoted as c(3×10 8 m·s-1 ), let the wavelength be λ(m), then the photon energy e is expressed by the formula e=hc / λ. The wavelength dependence of activating photosynthesis varies depending on the type of light receptors such as photosynthetic pigments.

[0042] Photon flux (μmol·s -1 ) can be converted from the radiant flux (W) of the irradiated light. The relationship between the radiant flux and the photon flux is expressed by the following formula (1).

[0043] Radiant flux (W) = photon flux (μmol·s -1 )×Avogadro constant (mol -1 )×Planck constant h(Js)×speed of light(m·s -1 )÷wavelengthλ(m) (1)

[0044] Based on the above formula (1), the radiation flux (W) obtained by the light emitting device can be converted into a photon flux. After conversion, the photon fluxes in the range of 400 nm to 490 nm are accumulated to calculate the photon flux B of blue light. Similarly, the photon fluxes in the range of 620 nm to 700 nm are accumulated to calculate the photon flux R of red light.

[0045] Light-emitting components

[0046] The light emitting element 10 is used as an excitation light source, and is a light emitting element that emits light having a peak wavelength in the range of 380 nm to 490 nm. Thus, a light emitting device with high efficiency, high linearity of output power relative to input power, strong mechanical impact resistance and stability can be obtained. The range of the peak wavelength of the light emitting element is more preferably 390 nm to 480 nm, more preferably 420 nm to 470 nm, more preferably 440 nm to 460 nm, and particularly preferably 445 nm to 455 nm. As such a light emitting element, it is preferred to use a nitride semiconductor (In X Al Y Ga 1-X-Y The light emitting element has a light emitting spectrum of 30 nm or less and a half value width of 30 nm or less.

[0047] Fluorescent components

[0048] The fluorescent component 50 used in the light-emitting device 100 preferably includes a red phosphor 70 and a sealing material. The sealing material can use a resin selected from a thermoplastic resin and a thermosetting resin. If the ease of manufacturing is taken into consideration, the resin used as the sealing material can be, for example, a silicone resin and an epoxy resin. In addition to the red phosphor and the sealing material, the fluorescent component can also contain other components such as fillers, light stabilizers, and colorants. As fillers, for example, silicon dioxide, barium titanate, titanium oxide, aluminum oxide, etc. can be listed. The content of other components in the fluorescent component except the red phosphor and the sealing material is preferably 0.01 parts by mass or more and 20 parts by mass or less relative to 100 parts by mass of the sealing material. In the composition for the fluorescent component constituting the fluorescent component, the content of substances that become other components except the red phosphor and the resin that becomes the sealing material is preferably 0.01 parts by mass or more and 20 parts by mass or less relative to 100 parts by mass of the resin that becomes the sealing material.

[0049] The content of the red phosphor 70 in the fluorescent component is not particularly limited as long as the R / B ratio of the photon flux R of red light in the range of 620 nm to 700 nm to the photon flux B of blue light in the range of 400 nm to 490 nm is greater than 20 and is within the range of 200 or less. The content of the red phosphor in the fluorescent component 50 can be set to, for example, 5 parts by mass to 150 parts by mass, preferably 8 parts by mass to 130 parts by mass, more preferably 10 parts by mass to 120 parts by mass, and further preferably 12 parts by mass to 100 parts by mass, relative to 100 parts by mass of the sealing material. If the content of the red phosphor 70 in the fluorescent component 50 is within the above range, the wavelength of the light emitted by the light-emitting element 10 can be efficiently converted by the red phosphor, and the blue light as the excitation light from the light-emitting element will not be transmitted, so that the red light can be supplemented. In addition, if the content of the red phosphor 70 in the fluorescent component 50 is within the above range, the red light will not be attenuated due to the self-absorption of the red phosphor, and the red light can be supplemented. Furthermore, if the content of the red phosphor 70 in the fluorescent component 50 is within the above range, when the above-mentioned light-emitting device for supplementing red light is combined with an existing light source for emitting white light, the red light can be supplemented effectively without destroying the spectral balance of the light emitted from the existing light source for emitting white light.

[0050] Red phosphor

[0051] The red phosphor 70 is a phosphor that is excited by the light from the light emitting element 10 and emits light having one or more emission peak wavelengths in the range of 580 nm to 680 nm. Examples of the red phosphor include Eu 2+ Activated nitride phosphor, Mn 4+ Activated fluorogermanate phosphor, Eu2+ Activated alkaline earth sulfide phosphor and Mn 4+ activated halide phosphors, etc. As the red phosphor, one selected from these phosphors may be used alone, or two or more may be used in combination.

[0052] The red phosphor preferably includes: a red phosphor having at least one element selected from Sr and Ca and Al in its composition, and containing Eu 2+ The red phosphor preferably includes at least one phosphor selected from the following phosphors: a phosphor containing at least one element selected from alkaline earth metal elements and at least one element selected from alkali metal elements, and containing Eu 2+ Activated aluminum nitride phosphor; 4+ Activated fluorogermanate phosphor; containing Eu 2+ An activated calcium sulfide or strontium sulfide phosphor; and a phosphor having an alkali metal element and an ammonium ion (NH4 + ) and at least one element selected from Group 4 elements and Group 14 elements, and including Mn 4+ Activated fluoride phosphor.

[0053] Specifically, the red phosphor 70 includes phosphors having any composition shown in the following formulas (I) to (VI). Among them, the red phosphor preferably includes a phosphor containing silicon nitride having a composition shown in the following formula (I). The phosphor having any composition shown in the following formulas (I) to (VI) emits red light due to the excitation light from the light-emitting element. In the light-emitting spectrum of the light-emitting device, the half-value width of the light-emitting peak existing in the range of 580 nm to 680 nm is greater than 40 nm, and the light-emitting peak is a relatively flat shape. The light-emitting peak existing in the range of 580 nm to 680 nm of the red phosphor 70 has a relatively flat shape because its half-value width is greater than 40 nm. Therefore, the light receptors of more types of plants can absorb the supplemented red light in the form of light energy, or perceive the supplemented red light as a light signal, which can stably promote plant growth or enhance the functional nutrients of plants, and can supply red light.

[0054] (Ca 1-s-t Sr s Eu t ) x Al u Si v N w (I)

[0055] (In formula (I), s, t, u, v, w and x are numbers satisfying 0≤s≤1, 0<t<1.0, 0<s+t<1.0, 0.8≤x≤1.0, 0.8≤u≤1.2, 0.8≤v≤1.2, 1.9≤u+v≤2.1, 2.5≤w≤3.5, respectively). The phosphor containing the composition represented by formula (I) is sometimes also represented as CaAlSiN3:Eu phosphor or (Sr, Ca)AlSiN3:Eu phosphor. In the above formula (I), the variable t is the molar ratio of the activating element Eu in the composition represented by the above formula (I). The variable t is preferably 0.0001≤t≤0.2, more preferably 0.0001≤t≤0.1, and further preferably 0.0002≤t≤0.05. In the above formula (I), the variable s is the molar ratio of Sr in the composition represented by the above formula (I). The variable s is preferably 0≤s≤0.98, more preferably 0≤s≤0.95, and even more preferably 0≤s≤0.9.

[0056] (Ca 1-p-q-r Sr p Ba q Eu r )2Si5N8 (II)

[0057] In formula (II), p, q and r are numbers satisfying 0≤p≤1.0, 0≤q≤1.0, 0<r<1.0 and p+q+r≤1.0.

[0058] (Ca a Sr 1-a-c-d Ba d Eu c ) f Li b Al3N e (III)

[0059] In formula (III), a, b, c, d, e and f are numbers satisfying 0≤a<1.0, 0.8≤b≤1.05, 0.001<c≤0.1, 0≤d≤0.2, 3.0≤e≤5.0, and 0.8≤f≤1.05, respectively.

[0060] (ij)MgO·(j / 2)Sc2O3·kMgF2·mCaF2·(1-n)GeO2·(n / 2)M 5 2O3:zMn 4+ (IV)

[0061] In formula (IV), M 5 is at least one selected from Al, Ga and In; i, j, k, m, n and z are numbers satisfying 2≤i≤4, 0≤j<0.5, 0<k<1.5, 0≤m<1.5, 0<n<0.5 and 0<z<0.05 respectively.

[0062] (Ca,Sr)S:Eu (V)

[0063] In this specification, in the formula representing the composition of the phosphor, the multiple elements separated by commas (,) refer to at least one element among these multiple elements contained in the composition. Regarding the multiple elements separated by commas (,) in the composition formula, at least one element selected from the multiple elements separated by commas can be included in the composition, and two or more elements can be combined from the above multiple elements. In addition, in this specification, in the formula representing the composition of the phosphor, the element before the colon (:) represents the mother crystal, and the element after the colon (:) represents the activation element.

[0064] A2[M 1 1-g Mn 4+ g F6] (VI)

[0065] In formula (VI), A is selected from K, Li, Na, Rb, Cs and NH4 + At least one of M 1 is at least one element selected from Group 4 elements and Group 14 elements, and g is a number satisfying 0<g<0.2.

[0066] Phosphors other than red phosphors

[0067] As long as the R / B ratio of the photon flux R of red light in the range of 620 nm to 700 nm to the photon flux B of blue light in the range of 400 nm to 490 nm is greater than 20 and less than 200, the light emitting device 100 may include other types of phosphors that emit light in a wavelength range other than the red light wavelength range in addition to the red phosphor 70. Examples of other types of phosphors include a green phosphor that absorbs a portion of light emitted from the light emitting element 10 and emits green light, a yellow phosphor that emits yellow light, and a far-infrared phosphor having a peak emission wavelength in the range of more than 680 nm.

[0068] Specific examples of green phosphors include phosphors having any of the compositions represented by the following formulae (i) and (iii).

[0069] M 11 8MgSi4O 16 X 11 2: Eu (i)

[0070] In formula (i), M 11 is at least one selected from Ca, Sr, Ba and Zn, X 11 It is at least one selected from the group consisting of F, Cl, Br and I.

[0071] Si 6-b Al b O b N 8-b :Eu (ii)

[0072] In the formula (ii), b satisfies 0<b<4.2.

[0073] M 13 Ga2S4:Eu (iii)

[0074] In formula (iii), M 13 It is at least one selected from the group consisting of Mg, Ca, Sr and Ba.

[0075] Furthermore, examples of green phosphors include (Ca, Sr, Ba)2SiO4:Eu, Ca3Sc2Si3O 12 : Silicate phosphors such as Ce.

[0076] Specific examples of the yellow phosphor include phosphors having any of the compositions represented by the following formulae (iv) to (v).

[0077] M 14 c / e Si 12-(c+d) Al c+d O d N 16-d :Eu (iv)

[0078] In formula (iv), M 14 is at least one selected from Sr, Ca, Li and Y. c is 0.5 to 5, d is 0 to 2.5, e is M 14 of charge.

[0079] M 15 3(Al,Ga)5O 12 :Ce (v)

[0080] In formula (v), M 15 It is Y or at least one selected from Lu, Gd, and Tb.

[0081] Specific examples of the far-infrared phosphor having a peak emission wavelength in a range exceeding 680 nm include phosphors having any of the compositions represented by the following formulae (vi) to (xi).

[0082] (Al 1-f Cr f )2O3 (vi)

[0083] In formula (vi), f is a number satisfying 0<f<1.

[0084] (Ln1-x-y Ce x Cr y )3(Al 1-z M 16 z )5O 12 (vii)

[0085] In formula (vii), Ln is at least one rare earth element selected from rare earth elements other than Ce, and M 16 is at least one element selected from Ga and In, and x, y and z are numbers satisfying 0.0002<x<0.50, 0.0001<y<0.05, and 0≤z≤0.8.

[0086] CaYAlO4:Mn (viii)

[0087] LiAlO2:Fe(ix)

[0088] CdS:Ag(x)

[0089] GdAlO3:Cr(xi)

[0090] White light source

[0091] The light-emitting device of the first embodiment of the present invention can be used in combination with an existing light source. The light-emitting device of the first embodiment of the present invention is preferably used in combination with a light source that emits white light. Even when the above-mentioned light-emitting device is used in combination with an existing light source such as a light source that emits white light, the spectral balance of the light emitted from the existing light source will not be destroyed, and a smaller number of light-emitting devices can be used compared to the existing light source to efficiently supplement the required red light according to the type of plant and the growth stage of the plant. Examples of white light include sunlight and light irradiated by various lamps. As a light source that emits white light, for example, at least one light source selected from the sun, a fluorescent lamp, an incandescent lamp, a metal halide lamp, a high-pressure sodium lamp, and an LED lamp can be used.

[0092] The light-emitting device of the first embodiment of the present invention can be used as a red light supplementary light-emitting device for promoting plant growth or enhancing functional nutrients of plants by being used in combination with a light source that emits white light.

[0093] The light-emitting device of the first embodiment of the present invention can supplement the red light required by plants, thereby activating photosynthesis of plants and promoting plant growth, and can enhance the functional nutrients of plants. The light-emitting device of the first embodiment of the present invention can be used as a light-emitting device for plant cultivation.

[0094] lighting fixtures

[0095] The light emitting device of the first embodiment of the present invention can be combined with a light source that emits light energy different from that of the light emitting device to form a lighting device. The light source that emits light energy different from that of the light emitting device is not limited to a light source that emits white light, and can include, for example, a light source that emits blue light. The lighting device formed by combining the light emitting device of the first embodiment of the present invention with a light source that emits light energy different from that of the light emitting device can irradiate the most suitable light energy to the plant according to the type of plant or the growth stage of the plant, and can transmit the most suitable light signal to the plant.

[0096] Plant cultivation methods

[0097] A plant cultivation method according to an embodiment of the present invention is a method for cultivating plants by irradiating plants with light emitted from a light emitting device 100. In the plant cultivation method, for example, in a plant factory where light irradiation can be artificially controlled, light emitted from the light emitting device 100 can be irradiated onto plants. The type of plant is not particularly limited, and the cultivation of plants can be promoted in a manner such that photosynthesis of the plant is activated, the stems, leaves, roots, or fruits of the plant have a good shape or weight, and the functional nutrients of the plant are enhanced.

[0098] Example

[0099] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples.

[0100] Examples 1 to 2 and Comparative Examples 1 to 5

[0101] Red phosphor

[0102] As the red phosphor, a CaAlSiN 3 :Eu phosphor having a peak emission wavelength of 660 nm that is excited by light from a light emitting element having a peak emission wavelength of 450 nm was used.

[0103] Light-emitting device

[0104] In the light emitting device 100 , a nitride semiconductor having a light emission peak wavelength of 450 nm is used as the light emitting element 10 .

[0105] Silicone resin is used as a sealing material constituting the fluorescent component 50. Red phosphor 70 is added to 100 parts by mass of silicone resin in the blending ratio (parts by mass) shown in Table 1, mixed and dispersed, and then degassed to obtain a composition for a fluorescent component constituting the fluorescent component. In the resin composition for a fluorescent component used in the light-emitting devices of Examples 1 to 2 and Comparative Examples 1 to 5, as shown in Table 1, the red phosphor is blended in such a way that the photon flux B of blue light in the range of 400 nm to 490 nm, the photon flux R of red light in the range of 620 nm to 700 nm, and the R / B ratio of the photon flux R of red light to the photon flux B of blue light respectively reach the values ​​shown in Table 1. These compositions for a fluorescent component are injected onto the light-emitting element 10 in the recess of the molded body 40 and filled into the recess, and further heated at 150° C. for 3 hours to cure the composition for a fluorescent component to form a fluorescent component 50. For Examples 1 to 2 and Comparative Examples 1 to 5, Figure 1 Hereinafter, the light emitting devices 100 of Examples 1 to 2 and Comparative Examples 1 to 5 are also referred to as light emitting devices for red fill light.

[0106] Photon Flux

[0107] The light emitted from the light emitting devices of Examples 1 to 2 and Comparative Examples 1 to 5 was measured using a spectrometer (PMA-12 manufactured by Hamamatsu Photonics KK). The obtained radiant flux (W) was converted into photon flux based on the following formula (1), and a spectrum of photon flux relative to wavelength was prepared to calculate the photon flux B of blue light obtained by summing the photon flux in the range of 400 nm to 490 nm, the photon flux R of red light obtained by summing the photon flux in the range of 620 nm to 700 nm, and the photosynthetic photon flux PPF obtained by summing the photon flux in the range of 400 nm to 700 nm. The results are shown in Table 1. In addition, Figure 2 The photon flux B of blue light in the range of 400nm to 490nm, the photon flux R of red light in the range of 620nm to 700nm, and the photosynthetic photon flux PPF in the range of 400nm to 700nm of the light emitted from the light emitting devices of each embodiment and comparative example are shown. Figure 2 In FIG. 1 , the horizontal axis represents the R / B ratio of the red fill light emitting device of each embodiment and comparative example. Figure 2 , for each of the light-emitting devices of Comparative Example 1, the light-emitting device of Comparative Example 2, the light-emitting device of Example 1, the light-emitting device of Example 2, the light-emitting device of Comparative Example 3, the light-emitting device of Comparative Example 4, and the light-emitting device of Comparative Example 5, from the left side, the blue light photon flux B (Blue PF), the red light photon flux R (Red PF), and the photosynthetic photon flux PPF are shown in sequence from the bottom.

[0108] Radiant flux (W) = photon flux (μmol·s -1 )×Avogadro constant (mol -1 )×Planck constant(Js)×speed of light(m·s -1 )÷wavelength(m) (1)

[0109] Half value width

[0110] From the spectrum of the photon flux relative to the wavelength of the light emitted from the light emitting device of each embodiment and comparative example, the half-value width (FWHM) of the light emitting peak existing in the range of 580nm to 680nm was obtained. The half-value width of the light emitting device of each embodiment and comparative example is the wavelength width of the light emitting peak that represents 50% of the maximum photon flux of the light emitting peak existing in the range of 580nm to 680nm in the light emitting spectrum. The results are shown in Table 1.

[0111] [Table 1]

[0112]

[0113] As shown in Table 1 and Figure 2 As shown, if the R / B ratio of the light emitted from the red fill light emitting device becomes larger, there is a tendency for the photosynthetic photon flux PPF to decrease. As shown in the red fill light emitting devices of Examples 1 and 2, if the R / B ratio exceeds 20 and is less than 200, the decrease in the photosynthetic photon flux PPF can be suppressed and the photon flux R of the red light can be increased, and the red light can be effectively supplemented according to the type of plant or the growth stage of the plant. In addition, as shown in the red fill light emitting devices of Examples 1 and 2, if the R / B ratio exceeds 20 and is less than 200, the photon flux B of the blue light is also small, the excitation light of the light emitting element will not be converted in wavelength due to the red phosphor, and the transmission of the blue light emitted from the light emitting device is suppressed. For example, when combined with an existing white light source, the red light can also be effectively supplemented without destroying the spectral balance of the light emitted from the existing light source.

[0114] As shown in Table 1 and Figure 2As shown, the value of photosynthetic photon flux PPF in the light-emitting devices of Comparative Examples 1 and 2 is greater than that of the light-emitting devices of Examples 1 and 2, but the value of photon flux B of blue light is also greater than that of the light-emitting devices of Examples 1 and 2. The excitation light of the light-emitting element is not converted by wavelength due to the red phosphor, but is released from the light-emitting device, causing blue light to leak out. In the light-emitting devices of Comparative Examples 1 and 2, for example, when used in combination with a light source that emits white light, in the spectrum of light emitted from the above light source, the green to yellow light components are relatively reduced due to the addition of blue light components, and the spectral balance of the white light emitted from the above light source is destroyed, and only red light cannot be effectively supplemented. In addition, the value of photosynthetic photon flux PPF in the light-emitting devices of Comparative Examples 3 to 5 becomes smaller than that of the light-emitting devices of Examples 1 and 2, and the photon flux R of red light also becomes smaller. The amount of red phosphor contained in the above light-emitting devices becomes too much, and the red light is attenuated due to self-absorption, and the red light cannot be effectively supplemented.

[0115] Combination of white LED light emitting device 1 and red fill light light emitting device

[0116] As a light source for emitting white light, a white LED light emitting device 1 (hereinafter sometimes referred to as "white LED 1") including a light emitting element having a peak emission wavelength in the range of 380 nm to 490 nm, a yellow phosphor, and a red phosphor was used. The light emitted from the white LED light emitting device 1 was measured using the above-mentioned spectrometer (PMA-12 manufactured by Hamamatsu Photonics KK). In the white LED light emitting device 1, when the photon flux B of blue light obtained by summing the photon flux in the range of 400 nm to 490 nm was set to 1, the photon flux G of green light obtained by summing the photon flux in the range of more than 490 nm and less than 570 nm was 1.7.

[0117] The spectrometer was used to measure the spectrum of the white LED light emitting device 1 and the spectrum of the red fill light emitting device of Examples 1 to 2 and Comparative Examples 1 to 5. Based on the spectrum of the white LED light emitting device 1 and the spectrum of the red fill light emitting device of each Example and Comparative Example, the photon flux B of blue light in the range of 400 nm to 490 nm of the mixed light of the light emitted from the white LED light emitting device 1 and the light emitted from the red fill light emitting device of each Example and Comparative Example was calculated. mix and the photon flux R of red light in the range of 620 nm to 700 nm mix . Taking the photon flux of red light in the mixed light R mix Relative to the photon flux of blue light in the mixed light B mix The ratio R mix / B mixIn order to achieve 3.5, the white LED light emitting device 1 is combined with the red fill light emitting device of each embodiment and comparative example. Below, the photon flux of blue light in the range of 400 nm to 490 nm of the mixed light obtained by combining the white light emitted from the light source and the light emitted from the red fill light emitting device is calculated based on the spectrum of the light emitted from the white light source and the spectrum of the light emitted from the red fill light emitting device, and is shown as B mix , the photon flux of red light in the range of 620nm to 700nm of the mixed light is represented as R mix .

[0118] Combination of white LED light emitting device 2 and red fill light light emitting device

[0119] As a light source for emitting white light, a white LED light emitting device 2 (hereinafter sometimes referred to as "white LED 2") including a light emitting element having a peak emission wavelength in the range of 380 nm to 490 nm, a green phosphor, a yellow phosphor, and a red phosphor was used. The light emitted from the white LED light emitting device 2 was measured using the above-mentioned spectrometer. In the white LED light emitting device 2, when the photon flux B of blue light obtained by summing the photon flux in the range of 400 nm to 490 nm was set to 1, the photon flux G of green light obtained by summing the photon flux in the range of more than 490 nm and less than 570 nm was 1.7.

[0120] The spectra of the white LED light emitting device 2 and the spectra of the red fill light emitting devices of Examples 1 to 2 and Comparative Examples 1 to 5 were measured using the spectrometer. Based on the spectra of the white LED light emitting device 2 and the spectra of the red fill light emitting devices of the Examples and Comparative Examples, the photon flux B of blue light in the range of 400 nm to 490 nm of the mixed light of the light emitted from the white LED light emitting device 2 and the light emitted from the red fill light emitting devices of the Examples and Comparative Examples was calculated. mix and the photon flux R of red light in the range of 620 nm to 700 nm mix . Taking the photon flux of red light in the mixed light R mix Relative to the photon flux of blue light in the mixed light B mix The ratio R mix / B mix In order to achieve 3.5, the white LED light emitting device 2 is combined with the red fill light light emitting device of each embodiment and comparative example.

[0121] Photon Flux

[0122] The above-mentioned spectrometer (PMA-12 manufactured by Hamamatsu Photonics KK) is used to measure the light emitted from the white LED light-emitting device 1 or 2 and the light emitted from the red fill light-emitting device of each embodiment and comparative example. By combining the obtained spectrum or radiant flux data, the spectrum or radiant flux of the mixed light obtained by combining the white LED light-emitting device 1 or 2 and the red fill light-emitting device of each embodiment and comparative example is obtained. Based on the above formula (1), they are converted into photon fluxes, and a spectrum of photon flux is prepared. The photon fluxes in the range of more than 400nm and less than 700nm are accumulated to calculate the photosynthetic photon flux PPF. The results are shown in Tables 2, 3 and Figure 3 . Figure 4 In the figure, the photon flux of the peak wavelength of light emission at 450nm is set to 1, and the spectrum of the relative photon flux of light emitted from the white LED light-emitting device 1 alone, the spectrum of the relative photon flux of the mixed light of the light emitted from the white LED light-emitting device 1 and the light emitted from the red fill light light-emitting device of Example 1, and the spectrum of the relative photon flux of the mixed light of the light emitted from the white LED light-emitting device 1 and the light emitted from the red fill light light-emitting device of Comparative Example 2 are shown. Figure 5 In the figure, the photon flux of the peak wavelength of light emission at 450nm is set to 1, and the spectrum of the relative photon flux of light emitted from the white LED light-emitting device 1 alone, the spectrum of the relative photon flux of the mixed light of the light emitted from the white LED light-emitting device 1 and the light emitted from the red fill light light-emitting device of Example 2, and the spectrum of the relative photon flux of the mixed light of the light emitted from the white LED light-emitting device 1 and the light emitted from the red fill light light-emitting device of Comparative Example 2 are shown.

[0123] G / B maintenance rate

[0124] The photon flux B of blue light in the range of 400 nm to 490 nm and the photon flux G of green light in the range of more than 490 nm to 570 nm of the light emitted from the white LED light emitting device 1 or 2 alone are calculated in the same manner as the above-mentioned photon flux. As described above, when the photon flux B of blue light in the range of 400 nm to 490 nm of the light emitted from the white LED light emitting device 1 or 2 alone is 1, the photon flux G of green light in the range of more than 490 nm to 570 nm is 1.7 (ratio G / B=1.7 / 1).

[0125] In addition, the red light photon flux R mix Photon flux relative to blue light B rmix The ratio R mix / B mmixThe white LED light emitting device 1 is obtained by combining the light emitted from the white LED light emitting device 1 in such a way that the wavelength is 3.5. The photon flux B of blue light in the range of 400 nm to 490 nm and the photon flux G of green light in the range of more than 490 nm to 570 nm of the mixed light emitted from the white LED light emitting device 1 and the light emitted from the red fill light emitting device of each embodiment and comparative example is calculated in the same manner as the above-mentioned photon flux. The ratio G / B of the light emitted from the white LED light emitting device 1 or 2 alone is set to 100%, and the ratio of the ratio G / B of each mixed light obtained by combining the white LED light emitting device 1 or 2 with the red fill light emitting device of each embodiment and comparative example to the ratio G / B of the light emitted from the white LED light emitting device 1 or 2 alone is expressed as the G / B maintenance rate (%). The closer the value of the G / B maintenance rate is to 100, it means that even when the red light of the red fill light emitting device is filled, the green light component is not reduced, and the spectral balance of the light emitted from the white LED light emitting device alone is maintained.

[0126] Number ratio of white LED light-emitting devices (%)

[0127] The red light photon flux R mix Photon flux relative to blue light B mix The ratio R mix / B mix The total number of light-emitting devices obtained by combining the white LED light-emitting device 1 or 2 with the red fill light light-emitting device of each embodiment and comparative example is set to 100% in a manner to achieve 3.5, and the number ratio (%) is used to represent the ratio of the number of white LED light-emitting devices to the total number of white LED light-emitting devices 1 or 2 and the red fill light light-emitting devices of each embodiment and comparative example. The results are shown in Tables 2 and 3 and Figure 3 For example, with a ratio R mix / B mix When the white LED light emitting device and the light emitting device of Comparative Example 1 are combined in such a way as to reach 3.5, the number ratio of the white LED light emitting device is less than 10%, and the number ratio of the light emitting device of Comparative Example 1 is more than 90%. mix / B mix The method of achieving a light mixing ratio of 3.5 is to combine the white LED light emitting device 1 or 2 with the red fill light light emitting device of Comparative Example 1. For each white LED light emitting device 1 or 2, nine red fill light light emitting devices of Comparative Example 1 are required.

[0128] [Table 2]

[0129]

[0130] [Table 3]

[0131]

[0132] As shown in Table 2 and Figure 3 As shown in FIG. 1 , when the red fill light emitting device of Example 1 with an R / B ratio of 36 and Example 2 with an R / B ratio of 101 are combined with the white LED emitting device 1, the number ratio of the white LED emitting device 1 is close to 50%. mix Photon flux relative to blue light B mix The ratio R mix / B mix The white LED light-emitting device 1 is combined with the red fill-light light-emitting device of Example 1 or 2 in a manner to achieve 3.5, and the number ratio of the white LED light-emitting device 1 to the red fill-light light-emitting device of Example 1 or 2 reaches about 1:1 (50%:50%). From this result, it can be confirmed that: compared with the existing white light source, a smaller number of red fill-light light-emitting devices can be used to effectively fill in red light. In addition, it can be seen that: the red fill-light light-emitting devices of Examples 1 and 2 can suppress the reduction of photosynthetic photon flux PPF, and effectively fill in red light according to the type of plant or the growth stage of the plant. In particular, it can be seen that: compared with the red fill-light device of Example 1, the red fill-light light-emitting device of Example 2 can suppress the reduction of photosynthetic photon flux PPF and more effectively fill in red light due to the high number ratio of the white LED light-emitting devices 1.

[0133] In addition, as shown in Table 3, when the red fill light emitting devices of Examples 1 and 2 are combined with the white LED emitting devices 2, the number ratio of the white LED emitting devices 2 is close to 60%. mix Photon flux relative to blue light B mix The ratio R mix / B mix The white LED light-emitting device 2 is combined with the red fill-light light-emitting device of Example 1 or 2 in a manner to achieve 3.5, and the number ratio of the white LED light-emitting device 2 to the red fill-light light-emitting device of Example 1 or 2 reaches about 6:4 (60%:40%). From this result, it can be confirmed that compared with the existing white light source, a smaller number of red fill-light light-emitting devices can be used to more effectively fill the red light. It can be seen that compared with the red fill-light device of Example 1, the red fill-light light-emitting device of Example 2 can suppress the reduction of photosynthetic photon flux PPF and fill the red light more effectively because of the high number ratio of the white LED light-emitting devices 2 and the high G / B maintenance rate.

[0134] As shown in Tables 2 and 3, it can be confirmed that when the red fill light emitting device of Examples 1 and 2 is combined with the white LED light emitting device 1 or 2, the G / B maintenance rate is as high as more than 90%, and the green-yellow light components are not reduced in the spectrum of the light emitted by the white LED light emitting device 1 or 2, and the spectrum balance of the light emitted by the white LED light emitting device 1 or 2 can be maintained, and the red light can be effectively filled in. In particular, when the red fill light emitting device of Example 2 is combined with the white LED light emitting device 1 and the white LED light emitting device 2, the G / B maintenance rate is larger than that of the red fill light emitting device of Example 1, and the red light can be filled in more effectively.

[0135] like Figure 4 As shown, it can be confirmed that: in the spectrum of the photon flux of the mixed light obtained by combining the white LED light-emitting device 1 with the red fill light light-emitting device of Example 1, the spectrum in the range of greater than 490nm and less than 570nm shows a shape similar to the spectrum in the range of greater than 490nm and less than 570nm of the white LED light-emitting device 1 alone, which can maintain the spectral balance of the light emitted by the white LED light-emitting device 1 and effectively fill in the red light in the range of greater than 620nm and less than 700nm.

[0136] like Figure 5 As shown, in the spectrum of the photon flux of the mixed light obtained by combining the white LED light-emitting device 1 with the red fill light light-emitting device of Example 2, the spectrum in the range of more than 490nm and less than 570nm shows a shape that is more similar to the spectrum in the range of more than 490nm and less than 570nm of the white LED light-emitting device 1 alone, and roughly overlaps with the spectrum in the range of more than 490nm and less than 570nm of the white LED light-emitting device 1 alone. Figure 5 The spectrum of the photon flux of the mixed light obtained by combining the white LED with the red fill light light-emitting device of Example 2 can confirm that when the red fill light light-emitting device of Example 2 is combined with the white LED light-emitting device 1, it can more effectively maintain the spectral balance of the light emitted by the white LED light-emitting device 1, and can more effectively fill in the red light in the range of above 620nm and below 700nm, compared with the case of being combined with the red fill light light-emitting device of Example 1.

[0137] As shown in Table 2, Figure 4 and Figure 5As shown, in the spectrum of the photon flux of the mixed light obtained by combining the white LED light emitting device 1 with the light emitting device of comparative example 2, the spectrum in the range of more than 490nm and less than 570nm is less than the spectrum in the range of more than 490nm and less than 570nm of the white LED light emitting device 1 alone. In the light emitting device of comparative example 2, since the R / B ratio of the photon flux R of red light to the photon flux B of blue light is as small as 10, the excitation light of the light emitting element is not wavelength-converted by the red phosphor, and the blue light emitted from the light emitting element of the light emitting device is transmitted, and the green to yellow light components are relatively reduced due to the addition of the blue light component, and the spectral balance of the light emitted by the existing light source is destroyed, and only the red light is not effectively supplemented.

[0138] As shown in Tables 2 and 3, when the light emitting device of Comparative Example 1 having an R / B ratio of 4 is combined with the white LED light emitting device 1 or 2, the number ratio of the white LED light emitting device 1 or 2 is less than 10%. mix Photon flux relative to blue light B mix The ratio R mix / B mix In order to achieve 3.5, the white LED light-emitting device 1 or 2 is combined with the red light-filling light-emitting device of the comparative example 1. For each white LED light-emitting device 1, nine light-emitting devices of the comparative example 1 are required. That is, it can be seen that the ratio of the number of white LED light-emitting devices to the number of red light-filling light-emitting devices of the comparative example 1 is about 1:9 (10%:90%). In order to fill in the red light, it is necessary to combine more light-emitting devices of the comparative example 1 than the white LED light-emitting device 1 or 2. When the light-emitting device of the comparative example 1 with an R / B ratio of 4 is combined with the white LED light-emitting device 1 or 2, the G / B maintenance rate is as low as 9.9 or 11.5. The blue light emitted from the light-emitting element of the light-emitting device of the comparative example 1 is transmitted, and the green to yellow light components are relatively reduced due to the addition of the blue light component. The spectral balance of the light emitted by the white LED light-emitting device 1 or 2 is destroyed, and only the red light is not effectively filled. When the light-emitting device of comparison example 2 with an R / B ratio of 10 is combined with the white LED light-emitting device 1 or 2, the G / B maintenance rate is also as low as 72.3 or 76.4. The blue light emitted from the light-emitting element of the light-emitting device of comparison example 2 is transmitted, and the green light to yellow light components are relatively reduced due to the addition of the blue light component. The spectral balance of the light emitted from the white LED light-emitting device 1 or 2 is destroyed, and the red light alone is not effectively supplemented.

[0139] As shown in Table 2 and Figure 3As shown, when the light-emitting devices of Comparative Examples 3 to 5 in which the R / B ratio exceeds 200 are combined with the white LED light-emitting device 1 or 2, the photosynthetic photon flux PPF in the range of above 400nm and below 700nm is smaller than the photosynthetic photon flux PPF when the white LED light-emitting device 1 or 2 is combined with the red fill light light-emitting device of Example 1 or 2, and the red light cannot be effectively fill-in.

[0140] Industrial Applicability

[0141] The light-emitting device of one embodiment of the present invention can efficiently supplement red light without destroying the spectral balance of light emitted by the existing light source, such as white light, depending on the type and growth stage of the plant, and can be used as a light-emitting device and lighting device for plant cultivation that can promote plant growth and enhance the functional nutrients of the plant. In addition, the plant cultivation method of irradiating plants with light emitted by the light-emitting device of one embodiment of the present invention can effectively supplement red light that is not compensated by light emitted by the existing light source, such as white light, to cultivate plants, and can be used in a plant factory.

[0142] Description of Reference Numerals

[0143] 10: light emitting element, 40: molded body, 50: fluorescent component, 70: red phosphor, 100: light emitting device.

Claims

1. A light emitting device comprising: A light-emitting element having a peak emission wavelength in the range of 380 nm to 490 nm; and a red phosphor that is excited by the light from the light emitting element and emits light having at least one emission peak wavelength in the range of 580 nm to 680 nm, A ratio R / B of a photon flux R of red light in a range of 620 nm to 700 nm inclusive to a photon flux B of blue light in a range of 400 nm to 490 nm inclusive is 80 to 200 inclusive.

2. The light emitting device according to claim 1, wherein: A ratio R / B of a photon flux R of red light in the range of 620 nm to 700 nm to a photon flux B of blue light in the range of 400 nm to 490 nm is greater than or equal to 80 and less than or equal to 120.

3. The light emitting device according to claim 1, wherein: The light-emitting device has at least one light-emitting peak in a light-emitting spectrum within a range of 580 nm to 680 nm, and a half-value width of the light-emitting peak is 40 nm to 120 nm.

4. The light emitting device according to claim 1, wherein: The light emitting device has at least one light emitting peak in a range of 580 nm to 680 nm in a light emitting spectrum, and a half-value width of the light emitting peak is 60 nm to 110 nm.

5. The light emitting device according to claim 1, wherein: The red phosphor comprises: a red phosphor containing at least one element selected from Sr and Ca and Al, and containing Eu 2+ Activated silicon nitride phosphor.

6. The light emitting device according to claim 1, wherein: The red phosphor comprises at least one phosphor selected from the following phosphors: The composition contains at least one element selected from alkaline earth metal elements and at least one element selected from alkali metal elements, and contains Eu 2+ Activated aluminum nitride phosphor; Mn 4+ activated fluorogermanate phosphor; Contains Eu 2+ An activated calcium sulfide or strontium sulfide phosphor; as well as In the composition, there is an alkali metal element and an ammonium ion NH4 + and at least one element selected from Group 4 elements or Group 14 elements, and including Mn 4+ Activated fluoride phosphor.

7. The light emitting device according to claim 5, wherein: The red phosphor comprises at least one phosphor selected from the following phosphors: The composition contains at least one element selected from alkaline earth metal elements and at least one element selected from alkali metal elements, and contains Eu 2+ Activated aluminum nitride phosphor; Mn 4+ activated fluorogermanate phosphor; Contains Eu 2+ An activated calcium sulfide or strontium sulfide phosphor; as well as In the composition, there is an alkali metal element and an ammonium ion NH4 + and at least one element selected from Group 4 elements or Group 14 elements, and including Mn 4+ Activated fluoride phosphor.

8. The light emitting device according to claim 1, wherein: The red phosphor includes a phosphor having a composition represented by the following formula (I): (That 1-s-t Sr. s I t ) x the u And v N w (I) In formula (I), s, t, u, v, w and x are numbers satisfying 0≤s≤1, 0<t<1.0, 0<s+t<1.0, 0.8≤x≤1.0, 0.8≤u≤1.2, 0.8≤v≤1.2, 1.9≤u+v≤2.1, and 2.5≤w≤3.5, respectively.

9. The light emitting device according to claim 1, wherein: The red phosphor includes a phosphor having any one of the following compositions represented by formulas (I) to (VI), (That 1-s-t Sr. s I t ) x the u And v N w (I) In formula (I), s, t, u, v, w and x are numbers satisfying 0≤s≤1, 0<t<1.0, 0<s+t<1.0, 0.8≤x≤1.0, 0.8≤u≤1.2, 0.8≤v≤1.2, 1.9≤u+v≤2.1, 2.5≤w≤3.5 respectively; (That 1-p-q-r Sr. p nay q I r )2Si5N8(II) In formula (II), p, q and r are numbers satisfying 0≤p≤1.0, 0≤q≤1.0, 0<r<1.0 and p+q+r≤1.0; (Ca a Sr 1-a-c-d Ba d Me c ) f Li b Al3N e (III) In formula (III), a, b, c, d, e and f are numbers satisfying 0≤a<1.0, 0.8≤b≤1.05, 0.001<c≤0.1, 0≤d≤0.2, 3.0≤e≤5.0, 0.8≤f≤1.05 respectively; (i-j)MgO·(j / 2)Sc2O3·kMgF2·mCaF2·(1-n)GeO2·(n / 2)M 5 2O3:zMn 4+ (IV) In formula (IV), M 5 is at least one selected from Al, Ga and In; i, j, k, m, n and z are numbers satisfying 2≤i≤4, 0≤j<0.5, 0<k<1.5, 0≤m<1.5, 0<n<0.5 and 0<z<0.05 respectively; (Ca,Sr)S:Eu (V); <h2 style=";text-align:left;direction:ltr">A2[M<h2 style=";text-align:left;direction:ltr"> 1 <h2 style=";text-align:left;direction:ltr"> 1-g <h2 style=";text-align:left;direction:ltr"> Mn<h2 style=";text-align:left;direction:ltr"> 4+ <h2 style=";text-align:left;direction:ltr"> g <h2 style=";text-align:left;direction:ltr"> F6] (VI) In formula (VI), A is selected from K, Li, Na, Rb, Cs and NH4 + At least one of M 1 is at least one element selected from Group 4 elements and Group 14 elements, and g is a number satisfying 0<g<0.

2.

10. The light-emitting device according to claim 1, comprising a phosphor having a composition represented by any one of the following formulae (i) to (iii): M 11 8MgSi4O 16 X 11 2:Eu (i) In formula (i), M 11 is at least one selected from Ca, Sr, Ba and Zn, X 11 is at least one selected from F, Cl, Br and I; And 6-b the b A b N 8-b :I (ii) In formula (ii), b satisfies 0<b<4.2; M 13 Ga2S4:Iu (iii) In formula (iii), M 13 It is at least one selected from the group consisting of Mg, Ca, Sr and Ba.

11. The light emitting device according to claim 1, comprising a silicate phosphor (Ca, Sr, Ba)2SiO4:Eu or Ca3Sc2Si3O 12 :Ce.

12. The light-emitting device according to claim 1, comprising a phosphor having any one of the compositions represented by the following formulae (iv) to (v): M 14 c / e And 12-（c+d） the c+d A d N 16-d :I (iv) In formula (iv), M 14 is at least one selected from Sr, Ca, Li and Y, c is 0.5 to 5, d is 0 to 2.5, e is M 14 The charge of M 15 3(Al,Ga)5O 12 :What (v) In formula (v), M 15 It is Y or at least one selected from Lu, Gd, and Tb.

13. The light-emitting device according to claim 1, comprising a phosphor having a composition represented by any one of the following formulas (vi) to (xi): (To the 1-f Cr f )2O3 (vi) In formula (vi), f is a number satisfying 0<f<1; (Inside) 1-x-y What x -R y )3(Al 1-z M 16 z )5O 12 (live) In formula (vii), Ln is at least one rare earth element selected from rare earth elements other than Ce, and M 16 is at least one element selected from Ga and In, and x, y and z are numbers satisfying 0.0002<x<0.50, 0.0001<y<0.05, 0≤z≤0.8; CaYAlO4:Mn (viii) LiAlO2:Fe (ix) CdS:Ag (x) GdAlO3:Cr (xi). The light emitting device according to claim 1 , used in combination with a light source emitting white light.

15. The light emitting device according to claim 14, wherein: The light source is selected from at least one of the sun, a fluorescent lamp, an incandescent lamp, a metal halide lamp, a high pressure sodium lamp and an LED lamp.

16. The light emitting device according to claim 1, which is used for plant cultivation.

17. The light emitting device according to claim 14, which is used for plant cultivation.

18. The light-emitting device according to claim 1, comprising a fluorescent component including the red phosphor and a sealing material, wherein a content of the red phosphor in the fluorescent component is in a range of 5 parts by mass or more and 150 parts by mass or less relative to 100 parts by mass of the sealing material.

19. A lighting device comprising a combination of the light emitting device according to any one of claims 1 to 18 and a light source that emits light energy different from that of the light emitting device.

20. A method for growing plants, wherein: The plant is irradiated with light emitted from the light emitting device according to any one of claims 1 to 18.

21. A method for growing plants, wherein: The light emitted from the light emitting device according to claim 1 and the light emitted from the light source emitting white light are irradiated onto the plant.

22. A plant cultivation method, comprising combining the light emitting device according to claim 1 and a first white LED light emitting device to irradiate light to plants, The light-emitting device described in claim 1 is a light-emitting device for red fill light. The first white LED light emitting device includes a light emitting element having a peak emission wavelength in the range of 380 nm to 490 nm, a yellow phosphor, and a red phosphor.

23. The plant cultivation method according to claim 22, wherein: In the first white LED light-emitting device, when the photon flux B of blue light obtained by adding the photon fluxes in the range of greater than 400nm and less than 490nm is set to 1, the photon flux G of green light obtained by adding the photon fluxes in the range of greater than 490nm and less than 570nm is 1.

7.

24. The plant cultivation method according to claim 22, wherein: The photon flux R of red light in the range of 620 nm to 700 nm in the mixed light of the light emitted from the first white LED light emitting device and the light emitted from the red fill light light emitting device mix Photon flux B relative to blue light in the range of 400nm to 490nm mix The ratio R mix / B mix is 3.

5.

25. The plant cultivation method according to claim 24, wherein: With respect to the total number of the first white LED light emitting devices and the red fill light light emitting devices being 100%, the number ratio of the first white LED light emitting devices is 50%.

26. The plant cultivation method according to claim 22, wherein: The ratio G / B of the photon flux B of blue light in the range of 400nm to 490nm to the photon flux G of green light in the range of more than 490nm to 570nm of the mixed light emitted from the combination of the first white LED light emitting device and the red fill light light emitting device is Relative to The ratio G / B of the photon flux B of blue light in the range of 400 nm to 490 nm to the photon flux G of green light in the range of more than 490 nm to 570 nm emitted from the first white LED light emitting device alone is The ratio, i.e. the G / B maintenance rate, exceeds 90%.

27. A plant cultivation method, comprising combining the light emitting device according to claim 1 and a second white LED light emitting device to irradiate light to plants, The light-emitting device described in claim 1 is a light-emitting device for red fill light. The second white LED light emitting device includes a light emitting element having a light emission peak wavelength in the range of 380 nm to 490 nm, a green phosphor, a yellow phosphor, and a red phosphor.

28. The plant cultivation method according to claim 27, wherein: In the second white LED light-emitting device, when the photon flux B of blue light obtained by adding the photon flux in the range of greater than 400nm and less than 490nm is set to 1, the photon flux G of green light obtained by adding the photon flux in the range of greater than 490nm and less than 570nm is 1.

7.

29. The plant cultivation method according to claim 27, wherein: The photon flux R of red light in the range of 620 nm to 700 nm in the mixed light of the light emitted from the second white LED light emitting device and the light emitted from the red fill light light emitting device mix Photon flux B relative to blue light in the range of 400nm to 490nm mix The ratio R mix / B mix is 3.

5.

30. The plant cultivation method according to claim 29, wherein: With respect to the total number of the second white LED light emitting devices and the red fill light light emitting devices being 100%, the number ratio of the second white LED light emitting devices is 60%.

31. The plant cultivation method according to claim 27, wherein: The ratio G / B of the photon flux B of blue light in the range of 400nm to 490nm to the photon flux G of green light in the range of more than 490nm to 570nm of the mixed light emitted from the combination of the second white LED light emitting device and the red fill light light emitting device is Relative to The ratio G / B of the photon flux B of blue light in the range of 400 nm to 490 nm to the photon flux G of green light in the range of more than 490 nm to 570 nm of the light emitted from the second white LED light emitting device alone is The ratio, i.e. the G / B maintenance rate, exceeds 90%.

32. A lighting device, which is obtained by combining a red fill light emitting device and a first white LED emitting device, The red fill light emitting device is a emitting device as claimed in any one of claims 1 to 17, The first white LED light emitting device includes a light emitting element having a peak emission wavelength in the range of 380 nm to 490 nm, a yellow phosphor, and a red phosphor.

33. The lighting device according to claim 32, wherein: The yellow phosphor includes a phosphor having a composition represented by any one of the following formulas (iv) to (v), and the red phosphor includes a phosphor having a composition represented by any one of the following formulas (I) to (VI). M 14 c / e And 12-（c+d） the c+d A d N 16-d :I (iv) In formula (iv), M 14 is at least one selected from Sr, Ca, Li and Y, c is 0.5 to 5, d is 0 to 2.5, e is M 14 The charge of M 15 3(Al,Ga)5O 12 :What (v) In formula (v), M 15 Y or at least one selected from Lu, Gd, and Tb; (That 1-s-t Sr. s I t ) x the u And v N w (I) In formula (I), s, t, u, v, w and x are numbers satisfying 0≤s≤1, 0<t<1.0, 0<s+t<1.0, 0.8≤x≤1.0, 0.8≤u≤1.2, 0.8≤v≤1.2, 1.9≤u+v≤2.1, 2.5≤w≤3.5 respectively; (That 1-p-q-r Sr. p nay q I r )2Si5N8(II) In formula (II), p, q and r are numbers satisfying 0≤p≤1.0, 0≤q≤1.0, 0<r<1.0 and p+q+r≤1.0; (Ca a Sr 1-a-c-d Ba d Me c ) f Li b Al3N e (III) In formula (III), a, b, c, d, e and f are numbers satisfying 0≤a<1.0, 0.8≤b≤1.05, 0.001<c≤0.1, 0≤d≤0.2, 3.0≤e≤5.0, 0.8≤f≤1.05 respectively; (i-j)MgO·(j / 2)Sc2O3·kMgF2·mCaF2·(1-n)GeO2·(n / 2)M 5 2O3:zMn 4+ (IV) In formula (IV), M 5 is at least one selected from Al, Ga and In; i, j, k, m, n and z are numbers satisfying 2≤i≤4, 0≤j<0.5, 0<k<1.5, 0≤m<1.5, 0<n<0.5 and 0<z<0.05 respectively; (Ca,Sr)S:Eu (V); <h2 style=";text-align:left;direction:ltr">A2[M<h2 style=";text-align:left;direction:ltr"> 1 <h2 style=";text-align:left;direction:ltr"> 1-g <h2 style=";text-align:left;direction:ltr"> Mn<h2 style=";text-align:left;direction:ltr"> 4+ <h2 style=";text-align:left;direction:ltr"> g <h2 style=";text-align:left;direction:ltr"> F6] (VI) In formula (VI), A is selected from K, Li, Na, Rb, Cs and NH4 + At least one of M 1 is at least one element selected from Group 4 elements and Group 14 elements, and g is a number satisfying 0<g<0.

2.

34. The lighting device according to claim 32, wherein: In the first white LED light-emitting device, when the photon flux B of blue light obtained by adding the photon fluxes in the range of greater than 400nm and less than 490nm is set to 1, the photon flux G of green light obtained by adding the photon fluxes in the range of greater than 490nm and less than 570nm is 1.

7.

35. The lighting device according to claim 32, wherein: The photon flux R of red light in the range of 620 nm to 700 nm in the mixed light of the light emitted from the first white LED light emitting device and the light emitted from the red fill light light emitting device mix Photon flux B relative to blue light in the range of 400nm to 490nm mix The ratio R mix / B mix is 3.

5.

36. The lighting device according to claim 32, wherein: With respect to the total number of the first white LED light emitting devices and the red fill light light emitting devices being 100%, the number ratio of the first white LED light emitting devices is 50%.

37. The lighting device according to claim 32, wherein: The ratio G / B of the photon flux B of blue light in the range of 400nm to 490nm to the photon flux G of green light in the range of more than 490nm to 570nm of the mixed light emitted from the combination of the first white LED light emitting device and the red fill light light emitting device is Relative to The ratio G / B of the photon flux B of blue light in the range of 400 nm to 490 nm to the photon flux G of green light in the range of more than 490 nm to 570 nm emitted from the first white LED light emitting device alone is The ratio, i.e. the G / B maintenance rate, exceeds 90%.

38. A lighting device, which is obtained by combining a red fill light emitting device and a second white LED emitting device, The red fill light emitting device is a emitting device as claimed in any one of claims 1 to 17, The second white LED light emitting device includes a light emitting element having a light emission peak wavelength in the range of 380 nm to 490 nm, a green phosphor, a yellow phosphor, and a red phosphor.

39. The lighting device according to claim 38, wherein: The green phosphor includes a phosphor having a composition represented by any one of the following formulas (i) to (iii), the yellow phosphor includes a phosphor having a composition represented by any one of the following formulas (iv) to (v), and the red phosphor includes a phosphor having a composition represented by any one of the following formulas (I) to (VI). M 11 8MgSi4O 16 X 11 2:Eu (i) In formula (i), M 11 is at least one selected from Ca, Sr, Ba and Zn, X 11 is at least one selected from F, Cl, Br and I; And 6-b the b A b N 8-b :I (ii) In formula (ii), b satisfies 0<b<4.2; M 13 Ga2S4:Iu (iii) In formula (iii), M 13 is at least one selected from the group consisting of Mg, Ca, Sr and Ba; M 14 c / e And 12-（c+d） the c+d A d N 16-d :I (iv) In formula (iv), M 14 is at least one selected from Sr, Ca, Li and Y, c is 0.5 to 5, d is 0 to 2.5, e is M 14 The charge of M 15 3(Al,Ga)5O 12 :What (v) In formula (v), M 15 Y or at least one selected from Lu, Gd, and Tb; (That 1-s-t Sr. s I t ) x the u And v N w (I) In formula (I), s, t, u, v, w and x are numbers satisfying 0≤s≤1, 0<t<1.0, 0<s+t<1.0, 0.8≤x≤1.0, 0.8≤u≤1.2, 0.8≤v≤1.2, 1.9≤u+v≤2.1, 2.5≤w≤3.5 respectively; (That 1-p-q-r Sr. p nay q I r )2Si5N8(II) In formula (II), p, q and r are numbers satisfying 0≤p≤1.0, 0≤q≤1.0, 0<r<1.0 and p+q+r≤1.0; (Ca a Sr 1-a-c-d Ba d Me c ) f Li b Al3N e (III) In formula (III), a, b, c, d, e and f are numbers satisfying 0≤a<1.0, 0.8≤b≤1.05, 0.001<c≤0.1, 0≤d≤0.2, 3.0≤e≤5.0, 0.8≤f≤1.05 respectively; (i-j)MgO·(j / 2)Sc2O3·kMgF2·mCaF2·(1-n)GeO2·(n / 2)M 5 2O3:zMn 4+ (IV) In formula (IV), M 5 is at least one selected from Al, Ga and In; i, j, k, m, n and z are numbers satisfying 2≤i≤4, 0≤j<0.5, 0<k<1.5, 0≤m<1.5, 0<n<0.5 and 0<z<0.05 respectively; (Ca,Sr)S:Eu (V); <h2 style=";text-align:left;direction:ltr">A2[M<h2 style=";text-align:left;direction:ltr"> 1 <h2 style=";text-align:left;direction:ltr"> 1-g <h2 style=";text-align:left;direction:ltr"> Mn<h2 style=";text-align:left;direction:ltr"> 4+ <h2 style=";text-align:left;direction:ltr"> g <h2 style=";text-align:left;direction:ltr"> F6] (VI) In formula (VI), A is selected from K, Li, Na, Rb, Cs and NH4 + At least one of M 1 is at least one element selected from Group 4 elements and Group 14 elements, and g is a number satisfying 0<g<0.

2.

40. The lighting device according to claim 38, wherein: In the second white LED light-emitting device, when the photon flux B of blue light obtained by adding the photon flux in the range of greater than 400nm and less than 490nm is set to 1, the photon flux G of green light obtained by adding the photon flux in the range of greater than 490nm and less than 570nm is 1.

7.

41. The lighting device according to claim 38, wherein: The photon flux R of red light in the range of 620 nm to 700 nm in the mixed light of the light emitted from the second white LED light emitting device and the light emitted from the red fill light light emitting device mix Photon flux B relative to blue light in the range of 400nm to 490nm mix The ratio R mix / B mix is 3.

5.

42. The lighting device according to claim 38, wherein: With respect to the total number of the second white LED light emitting devices and the red fill light light emitting devices being 100%, the number ratio of the second white LED light emitting devices is 60%.

43. The lighting device according to claim 38, wherein: The ratio G / B of the photon flux B of blue light in the range of 400nm to 490nm to the photon flux G of green light in the range of more than 490nm to 570nm of the mixed light emitted from the combination of the second white LED light emitting device and the red fill light light emitting device is Relative to The ratio G / B of the photon flux B of blue light in the range of 400 nm to 490 nm to the photon flux G of green light in the range of more than 490 nm to 570 nm of the light emitted from the second white LED light emitting device alone is The ratio, i.e. the G / B maintenance rate, exceeds 90%.

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