Light-emitting devices, lighting fixtures and street lights

Abstract

To provide a light-emitting device that emits a light in which scattering is suppressed, a lighting fixture, and a street light.SOLUTION: A light-emitting device comprises: a light emission element having a light emitting peak wavelength within a range of 400nm or more and 490nm or less; and a first fluorescence substance having the light emitting peak wavelength within a range of 570nm or more and 680nm or less. In the light-emitting device, at the time when an effective discharge luminance of the light emission of the light-emitting device of the range of 300nm or more and 800nm or less in consideration of a scattering strength curvature against a wavelength is B when a correlation color temperature is 1950K or less, an average color rendering evaluation index Ra is 70 or more, a luminance of the light emission of the light-emitting device of a range of 300nm or more and 800nm or less in consideration of a photopic vision reference ratio view feeling level of a human regulated by the CIE (International Commission on Illumination) is L, a scattering strength of a rayleigh scattering in 300nm of a wavelength is 1, a first scattering level index B / L of the effective discharge luminance B to the luminance L is 0.151 or less.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a light-emitting device, a lighting fixture, and a street light. [Background technology]

[0002] High-intensity discharge (HID) lamps, such as high-pressure mercury lamps, metal halide lamps, and high-pressure sodium lamps, are often used as light sources for lighting fixtures installed outdoors, such as street lamps and roadway lighting, because they have a longer life span and are more efficient than incandescent light bulbs. Light sources using these lamps use mercury as a luminous material, and in accordance with the regulations of the Minamata Convention on Mercury, there is a demand to replace them with lighting fixtures that use safer luminous materials.

[0003] For example, Patent Document 1 discloses a street light that includes a light source unit having multiple LED light sources and a roughly box-shaped reflection unit with a reflective surface, and that irradiates the road with both light from the light source and light reflected by the reflective surface from the light source. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-038826 A Summary of the Invention [Problem to be solved by the invention]

[0005] There are cases where light emitted from lighting equipment used outdoors is required to be reduced in scattering. Light equipment used outdoors includes street lamps and roadway lighting installed outdoors, as well as lighting equipment expected to be used outdoors, such as headlights that can be worn on a human head, flashlights, and portable lanterns using LEDs. In addition, there are cases where light equipment expected to be used indoors in places close to the outdoors, such as near entrances and windows, is required to be reduced in scattering. An object of one aspect of the present invention is to provide a light-emitting device, a lighting fixture, and a street light that can emit light with less scattering. [Means for solving the problem]

[0006] The first aspect is a light emitting device including a light emitting element having an emission peak wavelength in the range of 400 nm or more and 490 nm or less, and a first phosphor having an emission peak wavelength in the range of 570 nm or more and 680 nm or less, the light emitting device having a correlated color temperature of 1950 K or less, an average color rendering index Ra of 70 or more, and a full width at half maximum of an emission peak having the maximum emission intensity in an emission spectrum of the light emitting device being 110 nm or less, and emitting light in which a first scattering index B / L of the effective radiance B relative to the luminance L, defined by the following formula (1), is 0.151 or less, where L is the luminance of the light emitting device in the range of 300 nm or more and 800 nm or less taking into consideration the standard relative luminous efficiency of human photopic vision defined by CIE (Commission Internationale de Illumination), and B is the effective radiance of the light emitting device in the range of 300 nm or more and 800 nm or less taking into consideration a scattering intensity curve for wavelength when the scattering intensity of Rayleigh scattering at a wavelength of 300 nm is set to 1:

[0007]

number

[0008] A second aspect is a light emitting device comprising a light emitting element having an emission peak wavelength in the range of 400 nm or more and 490 nm or less, and a first phosphor having an emission peak wavelength in the range of 570 nm or more and 680 nm or less, the light emitting device having a correlated color temperature of 1950 K or less, an average color rendering index Ra of 70 or more, and a full width at half maximum of an emission peak having maximum emission intensity in an emission spectrum of the light emitting device being 110 nm or less, and emitting light in which a second scattering index B / A of the effective radiance B relative to the radiance A, defined by the following formula (2), is 0.060 or less, where A is the radiance of the light emitted by the light emitting device in the range of 300 nm or more and 800 nm or less, and B is the effective radiance of the light emitted by the light emitting device in the range of 300 nm or more and 800 nm or less, taking into consideration a scattering intensity curve versus wavelength when the scattering intensity of Rayleigh scattering at a wavelength of 300 nm is set to 1:

[0009]

number

[0010] A third aspect is a lamp including the light emitting device.

[0011] A fourth aspect is a street light equipped with the light emitting device. Effect of the Invention

[0012] According to one aspect of the present invention, it is possible to provide a light-emitting device, a lighting fixture, and a street light that emit light with reduced scattering. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 shows the standard luminous efficiency curve V(λ) for human photopic vision defined by the CIE and disclosed in Non-Patent Document 2. [Diagram 2]FIG. 2 is a graph showing the Rayleigh scattering intensity curve Dc(λ) where the shot intensity at a wavelength of 300 nm is taken as 1. [Figure 3A] FIG. 3A shows the CIE 1931 chromaticity diagram, the spectrum locus on the CIE 1931 chromaticity diagram, the black body radiation locus (Duv is 0.000) in the pure violet locus, and color deviation from the black body radiation locus. [Figure 3B] FIG. 3B is an enlarged view of a portion of FIG. 3A, and shows the blackbody radiation locus (Duv is 0.000) for chromaticity coordinates in the CIE 1931 chromaticity diagram where the x value is in the range of 0.300 to 0.600 and the y value is in the range of 0.250 to 0.500, and the color deviation from the blackbody radiation locus at each correlated color temperature (Duv: -0.020, -0.010, -0.008, +0.008, +0.010, +0.020). [Figure 4] FIG. 4 is a schematic cross-sectional view showing an example of a light emitting device according to the first configuration example. [Diagram 5] FIG. 5 is a schematic cross-sectional view showing an example of a light emitting device according to the first configuration example. [Figure 6] FIG. 6 is a schematic perspective view showing an example of the light emitting device according to the second configuration example. [Figure 7] FIG. 7 is a schematic cross-sectional view showing an example of a light emitting device according to the second configuration example. [Figure 8] FIG. 8 is a schematic perspective view showing an example of a light emitting device according to the third configuration example. [Figure 9] FIG. 9 is a schematic cross-sectional view showing an example of a light emitting device according to the third configuration example. [Figure 10] FIG. 10 is a diagram showing an example of a street light. [Figure 11] FIG. 11 is a diagram showing the spectral radiance of the light emitting device of Example 1 and the light emitting device of Comparative Example 1. In FIG. [Figure 12] FIG. 12 is a diagram showing the spectral radiance of the light emitting device of Example 2 and the light emitting device of Comparative Example 1. In FIG. [Figure 13] FIG. 13 is a diagram showing the spectral radiance of the light emitting device of Example 3 and the light emitting device of Comparative Example 1. In FIG. [Figure 14]FIG. 14 is a diagram showing the spectral radiance of the light emitting device of Example 4 and the light emitting device of Comparative Example 2. In FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, the embodiment 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, lamp, and street lamp. In addition, the members shown in the claims are in no way limited to the members of the embodiments. In particular, the dimensions, materials, shapes, and relative arrangements of the components described in the embodiments are merely illustrative examples, and are not intended to limit the scope of the present invention, unless otherwise specified. The relationship between the color name and the chromaticity coordinates, the relationship between the wavelength range of light and the color name of monochromatic light, etc., are in accordance with JIS Z8110. In this specification, the content of each component in the composition means the total amount of the multiple substances present in the composition when multiple substances corresponding to each component are present in the composition, unless otherwise specified. The full width at half maximum means the wavelength width of the emission peak that shows an emission intensity of 50% of the maximum emission intensity in the emission spectrum.

[0015] The light emitting device according to the first embodiment is a light emitting device including a light emitting element having an emission peak wavelength in the range of 400 nm or more and 490 nm or less, and a first phosphor having an emission peak wavelength in the range of 570 nm or more and 680 nm or less, the light emitting device having a correlated color temperature of 1950 K or less, an average color rendering index Ra of 70 or more, and a full width at half maximum of an emission peak having the maximum emission intensity in the emission spectrum of the light emitting device being 110 nm or less, and emitting light in which a first scattering index B / L of the effective radiance B relative to the luminance L, defined by the following formula (1), is 0.151 or less, where L is the luminance of the light emitting device in the range of 300 nm or more and 800 nm or less taking into account the standard relative luminous efficiency of human photopic vision defined by CIE (Commission Internationale de Illumination), and B is the effective radiance of the light emitting device in the range of 300 nm or more and 800 nm or less taking into account the scattering intensity curve for wavelength when the scattering intensity of Rayleigh scattering at a wavelength of 300 nm is set to 1:

[0016]

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[0017] The scattering of light caused by the interaction between light and particles is determined by the relative relationship between the wavelength λ of light and the size D of the particles. The size D of the particles contained in the air is much smaller than the wavelength λ of light. Rayleigh scattering is the scattering of light by particles smaller than the wavelength of light. In air, the shorter the wavelength of light, the more likely it is to be scattered. If the scattering of light is suppressed, the light can be made to reach farther. A light-emitting device that can make light reach farther can illuminate a relatively long distance ahead, for example, about 100 m, and can be used suitably for lighting used outdoors and lighting used indoors close to outdoors.

[0018] The luminance L of the light emitted by a light emitting device is calculated by the following formula (3). The luminance L of the light emitted by a light emitting device is the integral value of the spectral radiance S(λ) of the light emitting device in the range of 300 nm to 800 nm and the standard luminous efficiency curve V(λ) of human photopic vision defined by the CIE.

[0019]

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[0020] Non-Patent Document 2 discloses the standard luminous efficiency curve V(λ) for human photopic vision used in the sidelight system of the CIE 1931 color system (Non-Patent Document 2: Kobayashi Masaji et al., "Research into the Influence of the Spectral Distribution of Headlamp Light Sources on Discomfort Glare," Society of Automotive Engineers of Japan, Inc. Academic Conference Preprints, No. 5 to 10, pp. 9 to 14). FIG. 1 shows the standard luminous efficiency curve V(λ) for human photopic vision defined by the CIE disclosed in Non-Patent Document 2. FIG. 1 shows values ​​where the peak top of the standard luminous efficiency curve V(λ) for human photopic vision defined by the CIE is taken as 1.

[0021] FIG. 2 shows a scattering intensity curve Dc(λ) versus wavelength, where the scattering intensity of Rayleigh scattering at a wavelength of 300 nm is taken as 1.

[0022] The effective radiance B of the light emitted by the light emitting device is calculated by the following formula (4). The effective radiance B of the light emitted by the light emitting device is the integral value of the scattering intensity curve Dc(λ) and the spectral radiance S(λ) of the light emitting device in the range of 300 nm to 800 nm.

[0023]

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[0024] The first scattering index B / L of the light emitted by a light emitting device is the ratio of the effective radiance B of the light emitted by the light emitting device in the range of 300 nm to 800 nm, taking into account the scattering intensity curve for wavelength when the scattering intensity of Rayleigh scattering at a wavelength of 300 nm is set to 1, to the luminance L of the light emitted by the light emitting device in the range of 300 nm to 800 nm. The first scattering index B / L represents the degree of scattering of the light emitted by a light emitting device, taking into account the standard relative luminous efficiency of human photopic vision.

[0025] If the first scattering index B / L of the light emitted by the light emitting device is 0.151 or less, light with reduced scattering is emitted from the light emitting device when the standard relative luminous efficiency of human photopic vision is taken into consideration. If the first scattering index B / L of the light emitted by the light emitting device exceeds 0.151, scattering is not reduced, and it becomes difficult for the light to reach a long distance. The first scattering index B / L of the light emitted by the light emitting device is preferably 0.150 or less, and more preferably 0.149 or less. When Rayleigh scattering is taken into consideration, the first scattering index B / L of the light emitted by the light emitting device may be 0.01 or more, 0.02 or more, 0.05 or more, 0.10 or more, or 0.12 or more.

[0026] The light emitting device of the second embodiment is a light emitting device including a light emitting element having an emission peak wavelength in the range of 400 nm or more and 490 nm or less, and a first phosphor having an emission peak wavelength in the range of 570 nm or more and 680 nm or less, the light emitting device having a correlated color temperature of 1950 K or less, an average color rendering index Ra of 70 or more, and a full width at half maximum of an emission peak having the maximum emission intensity in an emission spectrum of the light emitting device being 110 nm or less, and emitting light in which a second scattering index B / A of the effective radiance B relative to the radiance A defined by the following formula (2) is 0.060 or less, where A is the radiance of the light emitted by the light emitting device in the range of 300 nm or more and 800 nm or less, and B is the effective radiance of the light emitted by the light emitting device in the range of 300 nm or more and 800 nm or less, taking into account a scattering intensity curve versus wavelength when the scattering intensity of Rayleigh scattering at a wavelength of 300 nm is set to 1:

[0027]

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[0028] The radiance A of the light emitted by the light emitting device is derived by the following formula (5): S(λ) in formula (5) is the spectral radiance of the light emitted by the light emitting device.

[0029]

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[0030] The second scattering index B / A of the emission of a light emitting device is the ratio of the effective radiance B of the emission of the light emitting device in the range of 300 nm to 800 nm, taking into account the scattering intensity curve for wavelength when the scattering intensity of Rayleigh scattering at a wavelength of 300 nm is set to 1, to the radiance A of the emission of the light emitting device in the range of 300 nm to 800 nm. The second scattering index B / A represents the degree of scattering of the emission of the light emitting device without taking into account the standard relative luminous efficiency of human photopic vision.

[0031] If the second scattering index B / A of the light emitted by the light emitting device is 0.060 or less, light with reduced scattering is emitted from the light emitting device even when the standard relative luminous efficiency of human photopic vision is not taken into consideration. If the second scattering index B / A of the light emitted by the light emitting device exceeds 0.060, scattering is not reduced, and it becomes difficult for the light to reach a long distance. The second scattering index B / A of the light emitted by the light emitting device is preferably 0.059 or less, and more preferably 0.058 or less. Taking into consideration Rayleigh scattering, the second scattering index B / A of the light emitted by the light emitting device may be 0.010 or more, 0.020 or more, or 0.030 or more.

[0032] High pressure sodium lamps, which are used as light sources for street lamps, roadway lighting, and other outdoor lighting fixtures, have a correlated color temperature of about 2000K to 2500K in the catalog value, and emit light with a large yellow to orange component. Depending on the characteristics of luminous flux and energy, light sources such as HID lamps, halogen lamps, and LED-based light-emitting devices are used for outdoor lighting fixtures.

[0033] The light emitting device emits light having a correlated color temperature of 1950K or less. The light emitting device emits light having a correlated color temperature that is approximately the same as or slightly lower than that of light emitted by, for example, a high-pressure sodium lamp. If the correlated color temperature of the light emitted by the light emitting device is 1950K or less, even if the light emitting device is used as a light source for a lamp used outdoors, such as a street lamp or roadway lamp, which uses a high-pressure sodium lamp as a light source, the light emitted does not cause discomfort. The correlated color temperature of the light emitted from the light emitting device may be 1920K or less, or may be 1900K or less. In order to prevent humans from feeling discomfort when the light emitted from the light emitting device is emitted from, for example, a lamp installed outdoors, the correlated color temperature is preferably 1000K or more, and may be 1200K or more, 1500K or more, or 1700K or more.

[0034] The average color rendering index Ra of the light emitted by the light emitting device may be 70 or more, 75 or more, 80 or more, 85 or more, or 90 or more. The average color rendering index Ra of the light emitted by the light emitting device may be measured in accordance with JIS Z8726. The closer the average color rendering index Ra of the light emitted by the light emitting device is to 100, the closer the color rendering is to the reference light source. Color rendering indicates the degree to which an illuminated object is visible. If the average color rendering index Ra of the light emitted by the light emitting device is 70 or more, the light emitted has sufficient color rendering even in factories, offices, and schools where general work is performed. The average color rendering index Ra of the light emitting device may be 99 or less.

[0035] The special color rendering index R9 of the light emitted by the light emitting device is an index for evaluating the color red. For light emitting devices used in lighting fixtures installed outdoors, such as street lamps and roadway lighting, or indoors, close to outdoors, there is often little need to check the color red. The special color rendering index R9 of the light emitted by the light emitting device may be a negative value. The special color rendering index R9 of the light emitted by the light emitting device may be within a range of minus (-)150 or more and plus (+)99 or less, within a range of -140 or more and +98 or less, or within a range of -135 or more and 95 or less.

[0036] The light emitting device has a full width at half maximum of an emission peak having a maximum emission intensity in an emission spectrum of the light emitting device of 110 nm or less, and may be 100 nm or less, 95 nm or less, 90 nm or less, 3 nm or more, 40 nm or more, 60 nm or more, or 70 nm or more. In the emission spectrum of the light emitting device, if the full width at half maximum of the emission peak having a maximum emission intensity is large, the light components on the long wavelength side that are difficult for humans to sense tend to be large, or the light components on the short wavelength side that are easily scattered by fine particles in the air tend to be large. If the light components on the long wavelength side increase, the luminance of the light emitted from the light emitting device tends to decrease. If the light components on the short wavelength side increase, the light tends to be difficult to reach far. In addition, in the emission spectrum of the light emitting device, if the full width at half maximum of the emission peak having a maximum emission intensity is small, the light components in a specific wavelength range tend to increase. In the emission spectrum of the light emitting device, if the emission peak having a maximum emission intensity is on the short wavelength side, the emission on the short wavelength side that is easily affected by fine particles in the air and easily scattered is not suppressed, and it becomes difficult to suppress scattering. In addition, when the emission spectrum of the light emitting device has an emission peak with the maximum emission intensity on the long wavelength side, and the amount of light components on the long wavelength side that are difficult for humans to sense increases, it becomes difficult to suppress a decrease in luminance. In order to provide a light emitting device that emits light with reduced scattering, the light emitting device preferably has a full width at half maximum of the emission peak with the maximum emission intensity in the emission spectrum of 110 nm or less.

[0037] The full width at half maximum of the emission peak having the maximum emission intensity in the emission spectrum of the light emitting device may be narrower than the full width at half maximum of the emission peak having the emission peak wavelength of the first phosphor included in the light emitting device or the full width at half maximum of the emission peak having the emission peak wavelength of the second phosphor. For example, when a first phosphor and a second phosphor having emission peak wavelengths in different wavelength ranges are included, the emission intensity of the portion where the emission spectrum of the first phosphor and the emission spectrum of the second phosphor overlap changes, and as a result, the emission spectrum of the mixed color light emitted from the light emitting device may be different from the emission spectrum of the first phosphor or the emission spectrum of the second phosphor, and may be narrower than the full width at half maximum of the emission peak having the emission peak wavelength of the first phosphor or the full width at half maximum of the emission peak having the emission peak wavelength of the second phosphor.

[0038] The light emitting device preferably has an emission peak wavelength having the maximum emission intensity in the emission spectrum in the range of 570 nm to 680 nm, and may have an emission peak wavelength in the range of 575 nm to 680 nm, or may have an emission peak wavelength in the range of 575 nm to 670 nm. The emission peak wavelength range having the maximum emission intensity in the emission spectrum of the light emitting device may overlap with the emission peak wavelength range of the first phosphor. The emission peak having the maximum emission intensity in the emission spectrum of the light emitting device may be due to the emission of the first phosphor.

[0039] Light emitting element The light-emitting element has an emission peak wavelength in the range of 400 nm to 490 nm. The emission peak wavelength of the light-emitting element is preferably in the range of 420 nm to 480 nm, and may be in the range of 440 nm to 460 nm. As a result, the light-emitting device has a correlated color temperature that does not cause a sense of incongruity when illuminating outdoors, satisfies the color rendering required for light illuminating outdoors, and emits light with reduced scattering. At least a part of the light emitted by the light-emitting element is used as excitation light for the first phosphor, and in the case where the second phosphor is included, it is used as excitation light for the second phosphor. In addition, a part of the light emitted by the light-emitting element is used as light emitted from the light-emitting device. The full width at half maximum of the emission peak having the emission peak wavelength in the emission spectrum of the light-emitting element is preferably 30 nm or less, more preferably 25 nm or less, and even more preferably 20 nm or less. For example, it is preferable to use a semiconductor light-emitting element using a nitride-based semiconductor as the light-emitting element. As a result, a stable light-emitting device can be obtained that is highly efficient, has high linearity of output relative to input, and is resistant to mechanical shock.

[0040] First phosphor The light emitting device includes a first phosphor having an emission peak wavelength in the range of 570 nm to 680 nm. The first phosphor is excited by the emission of a light emitting element having an emission peak wavelength in the range of 400 nm to 490 nm, and emits light having an emission peak wavelength in the range of 570 nm to 680 nm. The first phosphor may have an emission peak wavelength in the range of 575 nm to 670 nm, or may have an emission peak wavelength in the range of 580 nm to 660 nm. The first phosphor preferably has a full width at half maximum of an emission peak having an emission peak wavelength in the emission spectrum of the first phosphor in the range of 3 nm to 120 nm. The full width at half maximum of an emission peak having an emission peak wavelength in the emission spectrum of the first phosphor is preferably in the range of 3 nm to 15 nm, or in the range of 60 nm to 120 nm. For example, in order to emit light that has a correlated color temperature that does not feel unnatural as a lighting fixture installed outdoors, satisfies the color rendering required for a lighting fixture installed outdoors, and has reduced scattering, it is preferable that the full width at half maximum of the emission peak having an emission peak wavelength in the emission spectrum of the first phosphor is within the above-mentioned range.

[0041] The first phosphor preferably includes at least one selected from the group consisting of a first nitride phosphor having a composition represented by the following formula (1A), a second nitride phosphor having a composition represented by the following formula (1B), a fluoride phosphor having a composition represented by the following formula (1C), and a fluoride phosphor having a composition represented by the following formula (1C') different in composition from that of the following formula (1C). By including the first phosphor, the light emitting device can emit light with reduced scattering, which has a correlated color temperature of 1950K or less, an average color rendering index Ra of 70 or more, a full width at half maximum of an emission peak having the maximum emission intensity in the emission spectrum of the light emitting device of 110nm or less, and a first scattering index B / L of 0.151 or less. Furthermore, by including the first phosphor, the light emitting device can emit light with reduced scattering, which has a second scattering index B / A of 0.060 or less. M 1 2Si5N8:Eu (1A) (In formula (1A), M 1is an alkaline earth metal element containing at least one selected from the group consisting of Ca, Sr, and Ba.) Sr q Ca s Al t Si u N v :Eu (1B) (In formula (1B), q, s, t, u, v satisfy 0 ≦ q < 1, 0 < s ≦ 1, q + s ≦ 1, 0.9 ≦ t ≦ 1.1, 0.9 ≦ u ≦ 1.1, and 2.5 ≦ v ≦ 3.5 respectively.) A c [M 2 1-b Mn 4+ b F d (1C) (In formula (1C), A is at least one selected from the group consisting of K + , Li + , Na + , Rb + , Cs + , and NH4 + , and among them, K + is preferred. M 2 contains at least one element selected from the group consisting of Group 4 elements and Group 14 elements, and among them, Si and Ge are preferred. b satisfies 0 < b < 0.2, and c is the absolute value of the charge of the [M 2 1-b Mn 4+ b F d ion, and d satisfies 5 < d < 7.) A’ c’ [M 2 ’ 1-b’ Mn 4+ b’ F d’ (1C’) (In formula (1C’), A’ is at least one selected from the group consisting of K + , Li + , Na + , Rb + , Cs + , and NH4 + , and among them, K + is preferred. M 2' contains at least one element selected from the group consisting of Group 4 elements, Group 13 elements, and Group 14 elements, among which Si and Al are preferred. b' satisfies 0 < b' < 0.2, c' is 2 ' 1-b’ Mn 4+ b’ F d’ the absolute value of the charge of the ion, and d' satisfies 5 < d' < 7. ) In this specification, in the formula representing the composition of the phosphor, before the colon (:) represents the molar ratio of each element in 1 mol of the host crystal and the phosphor composition, and after the colon (:) represents the activating element.

[0042] The first phosphor may contain at least one phosphor selected from the group consisting of fluorogermanate phosphors, fourth nitride phosphors, and first sulfide phosphors. The fluorogermanate phosphor has, for example, a composition represented by the following formula (1D). The fourth nitride phosphor has, for example, a composition represented by the following formula (1E). The first sulfide phosphor has, for example, a composition represented by the following formula (1F). (i - j)MgO·(j / 2)Sc2O3·kMgF2·mCaF2·(1 - n)GeO2·(n / 2)M 3 2O3:Mn (1D) (In formula (1D), M 3 is at least one selected from the group consisting of Al, Ga, and In. i, j, k, m, and n each satisfy 2 ≤ i ≤ 4, 0 ≤ j < 0.5, 0 < k < 1.5, 0 ≤ m < 1.5, 0 ≤ n < 0.5. ) M 4 v2 M 5 w2 Al 3-y2 Si y2 N z2 :M 6 (1E) (In formula (1E), M 4 is at least one element selected from the group consisting of Ca, Sr, Ba, and Mg, M 5 is at least one element selected from the group consisting of Li, Na, and K, M 6is at least one element selected from the group consisting of Eu, Ce, Tb, and Mn, and v2, w2, y2, and z2 satisfy 0.80 ≦ v2 ≦ 1.05, 0.80 ≦ w2 ≦ 1.05, 0 ≦ y2 ≦ 0.5, and 3.0 ≦ z2 ≦ 5.0, respectively.) (Ca,Sr)S:Eu (1F) In the formulas showing the compositions of the phosphors in this specification, a plurality of elements described separated by commas (,) mean that at least one of these plurality of elements is included in the composition, and two or more of the plurality of elements may be combined and included.)

[0043] The fluorogermanate phosphor having the composition represented by formula (1D) may have the composition represented by the following formula (1d). 3.5MgO·0.5MgF2·GeO2:Mn (1d)

[0044] The fourth nitride phosphor having the composition represented by formula (1E) may have the composition represented by the following formula (1e). M 4 v2 M 5 w2 M 6 x2 Al 3-y2 Si y2 N z2 (1e) (In formula (1e), M 4 , M 5 and M 6 are synonymous with M 4 , M 5 and M 6 in formula (1E), respectively, v2, w2, y2, and z2 are synonymous with v2, w2, y2, and z2 in formula (1E), respectively, and x2 satisfies 0.001 < x2 ≦ 0.1.)

[0045] The fluorogermanate phosphor, the fourth nitride phosphor, and the first sulfide phosphor have an emission peak wavelength in the range of 570 nm to 680 nm, and preferably have an emission peak wavelength in the range of 600 nm to 630 nm. The fluorogermanate phosphor, the fourth nitride phosphor, and the first sulfide phosphor have a full width at half maximum of an emission peak having an emission peak wavelength in the emission spectrum of the first phosphor, for example, from 5 nm to 100 nm, and preferably from 6 nm to 90 nm.

[0046] The light emitting device of the first embodiment and the light emitting device of the second embodiment may contain at least one kind of the first phosphor alone, or may contain two or more kinds of the first phosphor. The light emitting device can emit light with a correlated color temperature of 1950K or less that does not cause discomfort when used outdoors or in a place close to outdoors even if it is indoors, an average color rendering index Ra of 70 or more, a full width at half maximum of an emission peak having the maximum emission intensity in the emission spectrum of the light emitting device of 110 nm or less, and a first scattering index B / L of 0.151 or less, and with suppressed scattering. The light emitting device can emit light with a correlated color temperature of 1950K or less, an average color rendering index Ra of 70 or more, a full width at half maximum of an emission peak having the maximum emission intensity in the emission spectrum of the light emitting device of 110 nm or less, and a second scattering index B / A of 0.060 or less, and with suppressed scattering, by containing the above-mentioned first phosphor.

[0047] The light emitting device of the first embodiment or the light emitting device of the second embodiment may contain, as a first phosphor, at least one selected from the group consisting of a fluorogermanate phosphor having a composition represented by formula (1D), a fluorogermanate phosphor having a composition represented by formula (1E), and a first sulfide phosphor having a composition represented by formula (1F). The first phosphor may contain at least one phosphor alone, or may contain two or more phosphors.

[0048] The content of the first phosphor contained in the light emitting device varies depending on the form of the light emitting device. When the first phosphor is contained in the wavelength conversion member of the light emitting device, the wavelength conversion member preferably contains a phosphor and a translucent material. The wavelength conversion member may include a wavelength conversion member containing a phosphor and a translucent material. The phosphor contained in the wavelength conversion member may have a total amount of the phosphor in a range of 10 parts by mass to 900 parts by mass, 15 parts by mass to 850 parts by mass, or 20 parts by mass to 800 parts by mass, relative to 100 parts by mass of the translucent material. The total amount of the phosphor refers to the total amount of the first phosphor when the light emitting device contains only the first phosphor and does not contain any other phosphor other than the first phosphor. The total amount of the phosphor refers to the total amount of the first phosphor and the second phosphor when the light emitting device contains the first phosphor and the second phosphor.

[0049] When the light emitting device includes a second phosphor described later, the content of the first phosphor contained in the light emitting device is preferably within a range of 5% by mass to 95% by mass with respect to the total amount of the first phosphor and the second phosphor. If the content of the first phosphor contained in the light emitting device is within a range of 5% by mass to 95% by mass with respect to the total amount of the first phosphor and the second phosphor, the light emitting device can emit light with a correlated color temperature of 1950 K or less, an average color rendering index Ra of 70 or more, a full width at half maximum of an emission peak having the maximum emission intensity in the emission spectrum of the light emitting device of 110 nm or less, a first scattering index B / L of 0.151 or less, and suppressed scattering. When the content of the first phosphor contained in the light emitting device is within a range of 5% by mass or more and 95% by mass or less with respect to the total amount of the first phosphor and the second phosphor, the light emitting device can emit light with a correlated color temperature of 1950 K or less, an average color rendering index Ra of 70 or more, a full width at half maximum of an emission peak having the maximum emission intensity in the emission spectrum of the light emitting device of 110 nm or less, a second scattering index B / A of 0.060 or less, and suppressed scattering. The content of the first phosphor contained in the light emitting device may be within a range of 8% by mass or more and 80% by mass or less, or may be within a range of 10% by mass or more and 70% by mass or less, or may be within a range of 11% by mass or more and 60% by mass or less with respect to the total amount of the first phosphor and the second phosphor.

[0050] Second phosphor The light emitting device preferably includes a second phosphor having an emission peak wavelength in the range of 480 nm to less than 570 nm. The second phosphor is excited by the emission of the light emitting element having an emission peak wavelength in the range of 400 nm to 490 nm, and emits light having an emission peak wavelength in the range of 480 nm to less than 570 nm. The second phosphor is excited by the light emitting element and may have an emission peak wavelength in the range of 490 nm to 565 nm, or may have an emission peak wavelength in the range of 495 nm to 560 nm. The second phosphor has a full width at half maximum of an emission peak having an emission peak wavelength in the emission spectrum of the second phosphor that is preferably in the range of 20 nm to 125 nm, may be in the range of 25 nm to 124 nm, or may be in the range of 30 nm to 123 nm. For example, in order to emit light with a correlated color temperature that is natural for a light-emitting device used outdoors or in a location close to outdoors even if indoors, with sufficient color rendering even in factories, offices, and schools where general work is performed, and with reduced scattering, it is preferable that the full width at half maximum of the emission peak having the emission peak wavelength in the emission spectrum of the second phosphor be within the above-mentioned range.

[0051] The second phosphor preferably includes at least one selected from the group consisting of a rare earth aluminate phosphor having a composition represented by the following formula (2A) and a third nitride phosphor having a composition represented by the following formula (2B). Ln 1 3(Al 1-a Ga a )5O 12 :Ce (2A) (In formula (2A), Ln 1 is at least one element selected from the group consisting of Y, Gd, Tb, and Lu, and a satisfies 0≦a≦0.5. La w Ln 2 x Si6N y :Ce z (2B) (In formula (2B), Ln 2It essentially contains at least one selected from the group consisting of Y and Gd, and may contain at least one selected from the group consisting of Sc and Lu. When the Ln 2 elements in 1 mol of the composition are taken as 100 mol%, the total of Y and Gd contained in Ln 2 is 90 mol% or more, and w, x, y and z satisfy 1.2 ≦ w ≦ 2.2, 0.5 ≦ x ≦ 1.2, 10 ≦ y ≦ 12.0, 0.5 ≦ z ≦ 1.2, 1.80 < w + x < 2.40, 2.9 ≦ w + x + z ≦ 3.1.) The rare earth aluminate phosphor having the composition represented by formula (2A) and the third nitride phosphor having the composition represented by formula (2B) have a full width at half maximum of the emission peak having the emission peak wavelength in the emission spectrum of the phosphor of, for example, 90 nm or more, preferably 100 nm or more, more preferably 110 nm or more, and also, for example, 125 nm or less, preferably 124 nm or less, more preferably 123 nm or less.

[0052] The second phosphor may contain at least one phosphor selected from the group consisting of alkaline earth metal aluminate phosphors and alkaline earth metal halosilicate phosphors. The alkaline earth metal aluminate phosphor is, for example, a phosphor containing at least strontium and activated with europium, and has, for example, a composition represented by the following formula (2C). The alkaline earth metal halosilicate phosphor is, for example, a phosphor containing at least calcium and chlorine and activated with europium, and has, for example, a composition represented by the following formula (2D). Sr4Al 14 O 25 :Eu (2C) (Ca,Sr,Ba)8MgSi4O 16 (F,Cl,Br)2:Eu (2D) In formula (2C), a part of Sr may be substituted with at least one element selected from the group consisting of Mg, Ca, Ba and Zn. The alkaline earth metal aluminate phosphor having a composition represented by formula (2C) and the alkaline earth metal halosilicate phosphor having a composition represented by formula (2D) have an emission peak wavelength in the range of 480 nm or more and less than 520 nm, and preferably have an emission peak wavelength in the range of 485 nm or more and 515 nm or less. The alkaline earth metal aluminate phosphor having a composition represented by formula (2C) and the alkaline earth metal halosilicate phosphor having a composition represented by formula (2D) have an emission peak having an emission peak wavelength in the emission spectrum of the phosphor, and a full width at half maximum of the emission peak is, for example, 30 nm or more, preferably 40 nm or more, more preferably 50 nm or more, and for example, 80 nm or less, preferably 70 nm or less.

[0053] The second phosphor may include at least one phosphor selected from the group consisting of a β-sialon phosphor, a second sulfide phosphor, a scandium-based phosphor, and an alkaline earth metal silicate-based phosphor. The β-sialon phosphor has a composition represented by the following formula (2E), for example. The second sulfide phosphor has a composition represented by the following formula (2F), for example. The scandium-based phosphor has a composition represented by the following formula (2G), for example. The alkaline earth metal silicate-based phosphor has a composition represented by the following formula (2H) or a composition represented by the following formula (2J). S 6-g Al g O g N 8-g :Eu(0 <g≦4.2) (2E) (Sr,M 7 )Ga2S4:Eu (2F) (In formula (2F), M 7 is at least one element selected from the group consisting of Be, Mg, Ca, Ba, and Zn. (Ca,Sr)Sc2O4:Ce (2G) (Ca,Sr)3(Sc,Mg)2Si3O 12 :Ce (2H) (Ca,Sr,Ba)2SiO4:Eu (2J)

[0054] The β-sialon phosphor, the second sulfide phosphor, the scandium phosphor, and the alkaline earth metal silicate phosphor have an emission peak wavelength in the range of 520 nm or more and less than 580 nm, and preferably have an emission peak wavelength in the range of 525 nm or more and 565 nm or less. The β-sialon phosphor, the second sulfide phosphor, the scandium phosphor, and the alkaline earth metal silicate phosphor have a full width at half maximum of an emission peak having an emission peak wavelength in the emission spectrum of the second phosphor of, for example, 20 nm or more, preferably 30 nm or more, and, for example, 120 nm or less, preferably 115 nm or less.

[0055] The second phosphor may include at least one phosphor selected from the group consisting of a rare earth aluminate phosphor having a composition represented by formula (2A), a third nitride phosphor having a composition represented by formula (2B), an alkaline earth metal aluminate phosphor having a composition represented by formula (2C), an alkaline earth metal halosilicate phosphor having a composition represented by formula (2D), a β-sialon phosphor having a composition represented by formula (2E), a second sulfide phosphor having a composition represented by formula (2F), a scandium-based phosphor having a composition represented by formula (2G), an alkaline earth metal silicate-based phosphor having a composition represented by formula (2H), and an alkaline earth metal silicate-based phosphor having a composition represented by formula (2J). The second phosphor may include at least one phosphor alone, or may include two or more phosphors.

[0056] The light emitting device preferably emits light with a color deviation Duv, which is a deviation from the black body radiation locus, of minus (-)0.008 or more and plus (+)0.008 or less. The color deviation Duv is the deviation of the light emitted from the light emitting device from the black body radiation locus, and is measured in accordance with JIS Z8725. Even when the correlated color temperature is relatively low, 1950K or less, if the color deviation Duv from the black body radiation locus (Duv is 0.000) on the CIE1931 chromaticity diagram is within the range of -0.008 or more and +0.008 or less, the color of the irradiated object is natural, and light that does not cause a sense of incongruity is emitted from the light emitting device. The light emitting device preferably emits light with a color deviation Duv, which is a deviation from the black body radiation locus at 1950 K or less, in the range of -0.008 to +0.008, more preferably emits light with a Duv in the range of -0.006 to +0.006, and even more preferably emits light with a Duv in the range of -0.003 to +0.003. If light with a color deviation Duv, which is a deviation from the black body radiation locus at 1950 K or less, below -0.008 or above +0.008 is emitted, the irradiated object may deviate from its natural color, causing a sense of discomfort to humans.

[0057] Fig. 3A is a diagram showing the spectrum locus on the CIE1931 chromaticity diagram, the black body radiation locus (Duv is 0.000) in the pure violet locus, and color deviations from the black body radiation locus. Fig. 3B is a partially enlarged view of Fig. 3A, showing the black body radiation locus in the range of chromaticity coordinate x value from 0.300 to 0.600 and y value from 0.250 to 0.500 in the CIE1931 chromaticity diagram, and the locus of color deviations from the black body radiation locus, Duv is -0.020, Duv is -0.010, Duv is -0.008, Duv is +0.008, Duv is +0.010, and Duv is +0.020. In Fig. 3B, the straight lines intersecting the blackbody radiation locus (Duv is 0.000) are iso-color temperature lines at each correlated color temperature (CCT is 1700K, 1950K, 2000K, 2700K, 3000K, 4000K, 5000K, 6500K). When the color deviation of the mixed color light emitted from the light emitting device has Duv of 0, there is no deviation from the blackbody radiation locus and it approximates to the blackbody radiation locus.

[0058] The light emitting device preferably emits light in which the second radiance in the range of 650 nm to 750 nm is 50% or less relative to the first radiance of 100% in the range of 400 nm to 750 nm. In the light emission of the light emitting device, the ratio of the second radiance in the range of 650 nm to 750 nm to the first radiance of 100% in the range of 400 nm to 750 nm is also referred to as Lp. When the ratio Lp of the second radiance to the first radiance of the light emitted from the light emitting device is 50% or less, the light emitted from the light emitting device has a relatively small amount of red component light, does not reduce luminance, does not cause discomfort to humans, and suppresses scattering. The ratio Lp of the second radiance to the first radiance of the light emitted from the light emitting device may be 45% or less, 40% or less, 35% or less, or 30% or less. The ratio Lp of the second radiance to the first radiance of light emitted from the light emitting device may be 5% or more, or 8% or more, in order to emit light having good color rendering properties.

[0059] The ratio Lp of the second radiance to the first radiance of the emission of the light emitting device is calculated by the following formula (6). The ratio Lp of the second radiance in the range of 650 nm to 750 nm to the first radiance of 100% in the range of 400 nm to 750 nm of the emission of the light emitting device indicates the ratio of long-wave red light component in the mixed light emitted from the light emitting device.

[0060]

number

[0061] The light emitting device preferably emits light having a first relative scattering index RS1 of 99.9% or less. The first relative scattering index RS1 refers to the ratio of the first scattering index B / L derived from the above formula (1) of a light emitting device emitting light having a correlated color temperature of 1950K or less, when the reference first scattering index B0 / L0 is set to 100%. The reference first scattering index B0 / L0 may be the first scattering index with the lowest value among light emitting devices to be measured that emit light having a correlated color temperature of more than 1950K and an average color rendering index Ra of 70 or more. When the first relative scattering index RS1 is 99.9% or less, light with less scattering is emitted than a light emitting device that emits light having a correlated color temperature of more than 1950K and an average color rendering index Ra of 70 or more. The first relative scattering index RS1 is preferably 20% or more. When light having a first relative scattering index RS1 of less than 20% is emitted from a light emitting device, the effect of suppressing scattering is large, but the color balance of the light is lost and color rendering is reduced. In order to satisfy the color rendering of an average color rendering index Ra of 70 or more and to suppress scattering, it is preferable that the light emitting device emits light having a first relative scattering index RS1 in the range of 20% to 99.9%. A light emitting device that emits light having a correlated color temperature of 1950K or less may have a first relative scattering index RS1 in the range of 30% to 99.5%, 40% to 99.0%, 50% to 98.5%, 70% or more, 80% or more, or 90% or more.

[0062] The reference first scattering index B0 / L0 of a light emitting device that emits light having a correlated color temperature exceeding 1950K and an average color rendering index Ra of 70 or more can be derived by the following formula (7).

[0063]

number

[0064] The first relative scattering index RS1 (%) can be derived by the following formula (8).

[0065]

number

[0066] The light emitting device preferably emits light having a second relative scattering index RS2 of 99.9% or less. The second relative scattering index RS2 refers to the ratio of the second scattering index B / A derived from the above formula (2) of a light emitting device emitting light having a correlated color temperature of 1950K or less when the reference second scattering index B0 / A0 is set to 100%. The reference second scattering index B0 / A0 may be the lowest second scattering index among light emitting devices to be measured that emit light having a correlated color temperature of more than 1950K and an average color rendering index Ra of 70 or more. If the second relative scattering index RS2 is 99.9% or less, light scattering can be suppressed more than that of a light emitting device that emits light having a correlated color temperature of more than 1950K and an average color rendering index Ra of 70 or more, even without considering the standard relative luminous efficiency of human photopic vision. The second relative scattering index RS2 is preferably 20% or more. When light having a second relative scattering index RS2 of less than 20% is emitted from the light emitting device, the effect of suppressing scattering is large, but the color balance of the light is lost and color rendering is reduced. In order to satisfy the color rendering of an average color rendering index Ra of 70 or more and to suppress scattering, it is preferable that the light emitting device emits light having a second relative scattering index RS2 in the range of 20% to 99.9%. A light emitting device that emits light having a correlated color temperature of 1950K or less may have a second relative scattering index RS2 in the range of 30% to 99.8%, 40% to 99.5%, 50% to 99.0%, 70% to 98.0%, 80% to 95.0%, or 90% or more.

[0067] The reference second scattering index B0 / A0 of a light emitting device that emits light having a correlated color temperature exceeding 1950K and an average color rendering index Ra of 70 or more can be derived by the following formula (9).

[0068]

number

[0069] The second relative scattering index RS2 (%) can be calculated by the following formula (10).

[0070]

number

[0071] An example of a light emitting device will be described with reference to the drawings. Figures 4 and 5 are schematic cross-sectional views showing a light emitting device of a first configuration example.

[0072] As shown in FIG. 4, the light emitting device 100 includes a light emitting element 10 having an emission peak wavelength in the range of 400 nm to 490 nm, and a first phosphor 71 that emits light when excited by light from the light emitting element.

[0073] The light emitting device 100 includes a molded body 41, a light emitting element 10, and a wavelength conversion member 21. The molded body 40 is formed by integrally molding a first lead 2, a second lead 3, and a resin part 42 containing a thermoplastic resin or a thermosetting resin. The molded body 41 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 2 and the second lead 3 via wires 60, respectively. The light emitting element 10 is covered with a wavelength conversion member 21. The wavelength conversion member 21 includes, for example, a phosphor 70 that converts the wavelength of light from the light emitting element 10, and a translucent material. The wavelength conversion member 21 also functions as a sealing member that covers the light emitting element 10 and the phosphor 70 in the recess of the molded body 40. The phosphor 70 includes a first phosphor 71 that is excited by light from the light emitting element and has an emission peak wavelength in the range of 570 nm to 680 nm. The first lead 2 and the second lead 3 connected to a pair of positive and negative electrodes of the light emitting element 10 have portions exposed toward the outside of the package constituting the light emitting device 100. Power can be supplied from the outside via the first lead 2 and the second lead 3 to cause the light emitting device 100 to emit light.

[0074] As shown in FIG. 5, the light emitting device 200 is the same as the light emitting device 100 shown in FIG. 4 except that the phosphor 70 includes a second phosphor 72 having an emission peak wavelength in the range of 480 nm or more and 570 nm or less, and the same components are given the same symbols.

[0075] The wavelength conversion member in the light emitting device of the first configuration example includes a phosphor and a light-transmitting material, and the light-transmitting material is preferably a resin. The light-transmitting material used in the wavelength conversion member may be at least one selected from the group consisting of resin, glass, and inorganic material. The resin is preferably at least one selected from the group consisting of epoxy resin, silicone resin, phenol resin, and polyimide resin. The inorganic material may be at least one selected from the group consisting of aluminum oxide and aluminum nitride. In addition to the phosphor and the light-transmitting material, the wavelength conversion member may contain a filler, a colorant, and a light diffusing material as necessary. Examples of the filler include silicon oxide, barium titanate, titanium oxide, and aluminum oxide. The content of other components other than the phosphor and the light-transmitting material contained in the wavelength conversion member can be in the range of 0.01 parts by mass to 50 parts by mass, or may be in the range of 0.1 parts by mass to 45 parts by mass, or may be in the range of 0.5 parts by mass to 40 parts by mass, based on 100 parts by mass of the light-transmitting material, in terms of the total content of the other components.

[0076] Method for manufacturing the light emitting device of the first configuration example A method for manufacturing the light emitting device of the first configuration example will be described. For details, the disclosure of JP 2010-062272 A can be referred to. The method for manufacturing the light emitting device preferably includes a molded body preparation step, a light emitting element arrangement step, a wavelength conversion member composition arrangement step, and a resin package formation step. When an aggregate molded body having a plurality of recesses is used as the molded body, the method may include a singulation step of separating the resin packages of each unit area after the resin package formation step.

[0077] In the step of preparing a molded body, a plurality of leads are integrally molded using a thermosetting resin or a thermoplastic resin to prepare a molded body having a recess having a side surface and a bottom surface. The molded body may be a molded body made of an aggregate base including a plurality of recesses. In the step of arranging the light-emitting element, the light-emitting element is arranged on the bottom surface of the recess of the molded body, and the positive and negative electrodes of the light-emitting element are connected to the first lead and the second lead by wires. In the step of placing the composition for a wavelength conversion member, the composition for a wavelength conversion member is placed in the recess of the molded body. In the resin package molding step, the composition for wavelength conversion material arranged in the recess of the molded body is cured to form a resin package, and a light emitting device is manufactured. When a molded body made of an aggregate base having a plurality of recesses is used, after the resin package forming step, the aggregate base having a plurality of recesses is separated into each resin package of each unit area in the singulation step, and individual light emitting devices are manufactured. In this manner, the light emitting device of the first configuration example shown in FIG. 4 or FIG. 5 can be manufactured.

[0078] Fig. 6 is a schematic perspective view showing the light emitting device of the second configuration example, and Fig. 7 is a schematic cross-sectional view showing the light emitting device of the second configuration example.

[0079] As shown in Fig. 6 and Fig. 7, the light emitting device 300 includes a support 1, a light emitting element 10 arranged on the support 1, a wavelength conversion member 22 including a phosphor 70 arranged on the upper surface of the light emitting element 10, and a light reflecting member 43 arranged on the support 1 on the side of the wavelength conversion member 22 and the light emitting element 10. A sealing member 50 is provided on the upper surface of the wavelength conversion member 22. The sealing member 50 has a lens portion 51 that is circular in a plan view and semispherical in a cross section, and a flange portion 52 that extends to the outer periphery of the lens portion 51. The lens portion 51 is circular in a plan view and semispherical in a cross section. The flange portion 52 extends to the outer periphery of the lens portion 51.

[0080] The wavelength conversion member 22 is formed larger than the light emitting element 10 in a plan view. In addition, a light-transmitting member 30 is provided between the side surface of the light emitting element 10 and the light reflecting member 43, the light-transmitting member 30 being in contact with the side surface of the light emitting element 10 and a part of the wavelength conversion member 22. The light-transmitting member 30 includes a light-transmitting joining member 32 provided between the light emitting element 10 and the wavelength conversion member 22. The light-transmitting joining member 32 can be an adhesive material that joins the light emitting element 10 and the wavelength conversion member 22. A part of the light-transmitting joining member 32 may be extended to a corner formed by the side surface of the light emitting element 10 and the main surface of the wavelength conversion member 22 on the light emitting element 10 side. In addition, as shown in FIG. 7, the cross-sectional shape of the extended light-transmitting joining member 32 can be an inverted triangle that spreads in the direction of the light reflecting member 43. The light-transmitting member 30 and the joining member 32 can be made of a resin having light transmittance. The support 1 is a member for mounting the light emitting element 10, the sealing member 50, etc. on the upper surface. The support 1 includes an insulating base material and a conductive member 4 such as a wiring pattern for mounting a light-emitting element on the surface of the base material. The light-reflecting member 43 is a member for covering the light-transmitting member 30, the bonding member 32, and the wavelength conversion member 22. For details of the light-emitting device of the second configuration example and the manufacturing method of the light-emitting device of the second configuration example described later, the disclosure of, for example, JP 2020-57756 A may be referred to.

[0081] The wavelength conversion member of the light emitting device of the second configuration example includes a phosphor and a light-transmitting material, similar to the wavelength conversion member of the light emitting device of the first configuration example. The phosphor includes a first phosphor excited by light from the light emitting element and having an emission peak wavelength in the range of 570 nm to 680 nm. The phosphor may include a second phosphor excited by light from the light emitting element and having an emission peak wavelength in the range of 480 nm to 570 nm. The light-transmitting material may be the same as the light-transmitting material used for the wavelength conversion member of the light emitting device of the first configuration example. In addition to the phosphor and the light-transmitting material, the wavelength conversion member of the light emitting device of the second configuration example may include a filler, a colorant, and a light diffusing material as necessary, similar to the wavelength conversion member of the light emitting device of the first configuration example.

[0082] Method for manufacturing the light emitting device according to the second configuration example An example of a method for manufacturing the light emitting device of the second configuration example will be described. The method for manufacturing the light emitting device of the second configuration example includes a step of arranging the light emitting elements, a step of preparing the wavelength conversion member, a step of forming the light transmissive member and the bonding member, a step of arranging the light reflecting member, and a step of arranging the sealing member, and may also include a step of separating each unit area.

[0083] In the step of arranging the light-emitting element, the light-emitting element is flip-chip mounted on a support prepared in advance. In the step of preparing the wavelength conversion member, a composition for wavelength conversion members containing a phosphor and a light-transmitting material is cured to form a plate-like, sheet-like or layer-like shape in advance, and the composition is divided into pieces of a size that can be arranged on the light-emitting element, to prepare a plate-like, sheet-like or layer-like wavelength conversion member. In the step of forming the light-transmitting member and the joining member, a light-transmitting adhesive is applied to the upper surface of the light-emitting element, and the wavelength conversion member is joined to the upper surface of the light-emitting element. The adhesive that protrudes from the interface between the light-emitting element and the wavelength conversion member extends from the side surface of the light-emitting element to the periphery of the wavelength conversion member, and is hardened in a fillet shape to form the light-transmitting member and the joining member. In the step of arranging the light-reflecting member, a white resin is arranged and hardened on the upper surface of the support so as to cover the side surfaces of the wavelength conversion member and the light-transmitting member, and the light-reflecting member is arranged. Finally, a sealing member is arranged on the upper surface of the wavelength conversion member and the light-reflecting member. This allows the light-emitting device of the second configuration example to be manufactured.

[0084] Fig. 8 is a schematic perspective view showing a light emitting device of the third configuration example, and Fig. 9 is a schematic cross-sectional view showing a light emitting device of the third configuration example.

[0085] As shown in Figs. 8 and 9, the light emitting device 400 has an external shape of a substantially rectangular parallelepiped. The light emitting device 400 includes a light emitting element 10, a covering member 44, and a wavelength conversion member 23 including a phosphor 70. Between the side surface of the light emitting element 10 and the covering member 44, a light transmissive member 33 is provided in contact with the side surface of the light emitting element 10 and a part of the wavelength conversion member 23. The light transmissive member 33 can be an adhesive that bonds the light emitting element 10 and the wavelength conversion member 23. The covering member 44 is disposed so as to cover the lower surface of the light emitting element 10, the electrodes 12p and 12n, the side surface of the light transmissive member 33, and the lower surface of the wavelength conversion member 23. The covering member 44 is light reflective and covers the side surface of the light emitting element 10 directly or indirectly. The outer surface of the covering member 44, together with the side surface of the wavelength conversion member 23, constitutes the side surface of the light emitting device 400. It is preferable that the outer surface of the covering member 44 and the side surface of the wavelength conversion member 23 are flush with each other. The covering member 44 covers the pair of electrodes 12p, 12n of the light emitting device 10 so that at least a part of each is exposed. The lower surface of the covering member 44 constitutes a part of the lower surface of the light emitting device 400. For details of the light emitting device of the third configuration example and the manufacturing method thereof, reference may be made to the disclosure of, for example, JP 2019-9429 A.

[0086] Method for manufacturing the light emitting device according to the third configuration example The manufacturing method of the light emitting device of the third configuration example will be outlined below. The manufacturing method of the light emitting device of the third configuration example includes a wavelength conversion member preparation step, a light transmissive member and light emitting element arrangement step, a light transmissive member formation step, and a covering member formation step, and may include an electrode exposure step after the covering member formation step, and may include a singulation step for separating each unit area.

[0087] In the wavelength conversion member preparation step, a wavelength conversion member composition containing a phosphor and a light-transmitting material is cured to form a plate, sheet, or layer in advance. In the light-transmitting member and light-emitting element arrangement step, a light-transmitting adhesive is applied to the upper surface of the wavelength conversion member, and the light-emitting element is arranged. In the light-transmitting member formation step, the adhesive protruding from the interface between the light-emitting element and the wavelength conversion member is extended from the side of the light-emitting element to the periphery of the wavelength conversion member, and is cured in a fillet shape to form the light-transmitting member. In the covering member formation step, a covering member is formed on the wavelength conversion member so as to bury the light-emitting element. By removing a part of the covering member, the electrode of the light-emitting element is exposed. If necessary, each unit area is cut into individual pieces. This allows the light-emitting device of the third configuration example to be manufactured.

[0088] Light equipment The lamp may include at least one of the above-mentioned light-emitting devices. The lamp may be configured with the above-mentioned light-emitting device, and may further include a reflecting member, a protective member, an accessory device for supplying power to the light-emitting device, and the like. The lamp may include a plurality of light-emitting devices. When the lamp includes a plurality of light-emitting devices, the lamp may include a plurality of the same light-emitting devices, or may include a plurality of light-emitting devices of different forms. In addition, the lamp may include a driving device capable of individually driving the plurality of light-emitting devices and adjusting the brightness of each light-emitting device. The lamp may be used in any of a direct-mount type, an embedded type, a hanging type, and the like. The lamp may be a lamp intended for outdoor installation such as a street lamp, a port, or a tunnel, or may be a lamp intended for outdoor use such as a headlight, a flashlight, or a portable lantern using an LED, or may be a lamp installed indoors or near the outdoors such as a window.

[0089] Street lights A street light may include at least one of the above-mentioned light emitting devices. FIG. 10 is a diagram showing an example of a street light. A street light 1000 includes a pole P installed on a sidewalk W or a roadway C and a support part S for a light emitting device Le. The support part S includes a light transmitting part T that covers the periphery of the light emitting device Le and transmits at least a part of the light emitted by the light emitting device Le, such as acrylic, polycarbonate, or glass. The street light 1000 can illuminate low places from high places by the light emitting device Le installed on the support part S integrated with the pole P. The street light is not limited to the example shown in FIG.

[0090] The street light may be not only a pole-type street light with a pole whose support part can be set to any height, but also a bracket-type street light in which the support part is supported by a bracket instead of a pole, a floodlight-type street light that illuminates from below upward, or a landscape material-integrated type street light that is incorporated into a landscape material such as a pillar or block. EXAMPLES

[0091] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0092] In the light emitting devices of the respective Examples and Comparative Examples, the following first phosphor and / or second phosphor were used.

[0093] First phosphor As the first phosphor, as shown in Table 1, second nitride phosphors SCASN-2, SCASN-3, SCASN-4, and SCASN-6, each having a different emission peak wavelength and full width at half maximum, and contained in a composition represented by formula (1B), a fluoride phosphor KSF contained in a composition represented by formula (1C), and a second nitride phosphor CASN contained in a composition represented by formula (1B) (in formula (1B), q = 0) were prepared.

[0094] Second phosphor As the second phosphor, as shown in Table 2, each of the second phosphors has a different emission peak wavelength and full width at half maximum, and is included in the composition represented by formula (2A). 12:LAG, a rare earth aluminate phosphor that is Ce, is included in the composition represented by Formula (2A), Y3(Al,Ga)5O 12 :Rare earth aluminate phosphors G-YAG1, G-YAG3, and G-YAG4 that are Ce (where a satisfies 0 < a ≤ 0.5), and Y3Al5O included in the composition represented by Formula (2A) 12 :Rare earth aluminate phosphors YAG1 and YAG2 that are Ce were prepared.

[0095] Measurement of the emission spectrum of the phosphor For each phosphor, light with an excitation wavelength of 450 nm was irradiated onto each phosphor using a quantum efficiency measurement device (QE-2000, manufactured by Otsuka Electronics Co., Ltd.), and the emission spectrum at room temperature (about 25 °C) was measured. The emission peak wavelength and full width at half maximum were measured from each emission spectrum. The results are shown in Tables 1 and 2.

[0096]

Table 1

[0097]

Table 2

[0098] Example 1 The light-emitting device 200 of the first configuration example was manufactured. Refer to FIG. 5 for the light-emitting device 200 of the first configuration example, which includes a first phosphor 71 and a second phosphor 72. As the light-emitting element 10, a light-emitting element 10 in which a nitride semiconductor layer having an emission peak wavelength of 450 nm was laminated was used. The size of the light-emitting element 10 was substantially square with a planar shape of about 700 mm on each side and a thickness of about 200 mm. As the first lead 2 and the second lead 3, a lead frame was used, and the first lead 2 and the second lead 3 were integrally molded using an epoxy resin to prepare a molded body 41 having a recess with a side surface and a bottom surface. The light-emitting element 10 was disposed on the bottom surface of the recess of the molded body 41, and the positive and negative electrodes of the light-emitting element 10 and the first lead 2 and the second lead 3 were connected by Au wires 60. Silicone resin was used as the light-transmitting material constituting wavelength conversion member 21. Phosphors shown in Table 3 were used as first phosphor 71 and second phosphor 72. The composition for wavelength conversion members was prepared by blending first phosphor 71 and second phosphor 72 as shown in Table 3 with 100 parts by mass of the light-transmitting material so that the correlated color temperature of mixed light of light from light-emitting element 10 and light of phosphor 70 containing first phosphor 71 and second phosphor 72 was close to 1850 K. The composition for wavelength conversion members was blended with 2 parts by mass of aluminum oxide as a filler with 100 parts by mass of silicone resin. Next, the prepared composition for wavelength conversion members was filled into the recesses of molded body 41. The composition for wavelength conversion member filled in the recess of the molded body 41 was heated at 150°C for 3 hours to harden it, forming a resin package equipped with a wavelength conversion member 21 including a first phosphor 71 and a second phosphor 72, thereby producing a light emitting device 200 of a first configuration example that emits light with a correlated color temperature of 1950K or less.

[0099] Example 2 A light emitting device 200 of a first configuration example was manufactured. The light emitting device 200 of the first configuration example includes a first phosphor 71 and a second phosphor 72. See FIG. In the wavelength conversion member preparation process, a composition for wavelength conversion members containing first phosphor 71 and second phosphor 72 was prepared so that the total amount of phosphor 70 and the blending ratio of first phosphor 71 to second phosphor 72 were as shown in Table 3, so that the correlated color temperature of mixed light of light from light emitting element 10 and light of phosphor 70 containing first phosphor 71 and second phosphor 72 would be around 1850 per 100 parts by mass of translucent material. A light emitting device 200 of a first configuration example was manufactured in the same manner as in Example 1, except that

[0100] Example 3 A light emitting device 200 of a first configuration example was manufactured. The light emitting device 200 of the first configuration example includes a first phosphor 71 and a second phosphor 72. See FIG. Phenyl silicone resin was used as the light-transmitting material constituting wavelength conversion member 21. As first phosphor 71 and second phosphor 72, phosphors shown in Table 3 were used. The composition for wavelength conversion members was prepared by blending first phosphor 71 and second phosphor 72 as shown in Table 3 with 100 parts by mass of the light-transmitting material so that the correlated color temperature of mixed light of light from light-emitting element 10 and light of phosphor 70 containing first phosphor 71 was close to 1850 K. The composition for wavelength conversion members was prepared by blending 15 parts by mass of silicon dioxide as a filler with 100 parts by mass of phenyl silicone resin. Next, the prepared composition for wavelength conversion members was filled into the recesses of molded body 41. The composition for the wavelength conversion member filled in the recess of the molded body 41 was heated at 150°C for 4 hours to harden it, forming a resin package equipped with a wavelength conversion member 21 including a first phosphor 71 and a second phosphor 72, thereby producing a light emitting device 200 of a first configuration example that emits light with a correlated color temperature of 1950K or less.

[0101] Example 4 A light emitting device 400 of the third configuration example was manufactured. For the light emitting device of the third configuration example, refer to Figs. 8 and 9.

[0102] Wavelength conversion material preparation process Silicone resin was used as the light-transmitting material constituting the wavelength conversion member 23. The first phosphor and the second phosphor were used as shown in Table 3. The composition for wavelength conversion member was mixed with the total amount of phosphor 70 and the mixing ratio of the first phosphor and the second phosphor as shown in Table 3 so that the correlated color temperature of the mixed light of the light from the light emitting element 10 and the light of phosphor 70 containing the first phosphor and the second phosphor was around 1850K per 100 parts by mass of the light-transmitting material. The composition for wavelength conversion member was mixed with 2 parts by mass of aluminum oxide as a filler per 100 parts by mass of silicone resin. Next, the prepared composition for wavelength conversion member was heated at 180°C for 2 hours to be cured into a sheet shape, and the sheet-shaped wavelength conversion member 22 was prepared.

[0103] Arrangement process of light-transmitting member and light-emitting element A light-transmitting adhesive, phenyl silicone resin, was applied to the upper surface of wavelength conversion member 23, and a light-emitting element 10 similar to that in Example 1 was joined thereto. Further, a light-transmitting adhesive was applied to the interface between the light-emitting element 10 and wavelength conversion member 23 and cured at 150°C for 4 hours to form a fillet-shaped hardened light-transmitting member 33 extending from the side of the light-emitting element 10 to the periphery of wavelength conversion member 23.

[0104] Forming process of the covering member A composition for a covering member was prepared, which contained a phenyl silicone resin and titanium oxide particles having an average particle size (catalog value) of 0.25 μm, and contained 60 parts by mass of titanium oxide particles per 100 parts by mass of the phenyl silicone resin. The composition for a covering member, which is a white resin, was placed on the upper surface of the wavelength conversion member 23 so as to cover the side surfaces of the wavelength conversion member 23 and the light-transmitting member 33 and to embed the light-emitting element 10, and was cured to form a covering member 44. The electrodes 12p and 12n of the light-emitting element 10 were exposed by removing a part of the covering member 44. The light-emitting element 10 was singulated to have a planar shape of approximately 1.1 mm square, which is approximately 0.195 mm larger in length and width than the planar shape of the light-emitting element 10, and the total thickness including the wavelength conversion member 33 and the covering member 44 was approximately 350 μm, and a light-emitting device 400 of a third configuration example was manufactured, which emits light with a correlated color temperature of 1950 K or less.

[0105] Comparative Example 1 A light emitting device according to the second configuration example was manufactured. For the light emitting device according to the second configuration example, see Figs. 6 and 7. In the wavelength conversion member preparation process, a composition for wavelength conversion members containing first phosphor 71 and second phosphor 72 was prepared so that the total amount of phosphor 70 and the blending ratio of the first phosphor to the second phosphor were as shown in Table 3, so that the correlated color temperature of the mixed light of the light from the light emitting element 10 and the light of phosphor 70 containing first phosphor 71 and second phosphor 72 would be around 2200 per 100 parts by mass of translucent material. A light emitting device 400 of a third configuration example was manufactured in the same manner as in Example 4.

[0106] Comparative Examples 2 and 3 A light emitting device 200 of a first configuration example was manufactured. The light emitting device 200 of the first configuration example includes a first phosphor 71 and a second phosphor 72. See FIG. In the wavelength conversion member preparation process, a composition for wavelength conversion members containing first phosphor 71 and second phosphor 72 was prepared so that the total amount of phosphor 70 and the blending ratio of the first phosphor to the second phosphor were as shown in Table 3, so that the correlated color temperature of the mixed light of the light from the light emitting element 10 and the light of phosphor 70 containing first phosphor 71 and second phosphor 72 would be around 1950 per 100 parts by mass of translucent material. A light emitting device 200 of a first configuration example was manufactured in the same manner as in Example 3.

[0107] The following measurements were carried out for each light-emitting device, and the results are shown in Table 3.

[0108] Emission spectrum of light emitting device The emission spectrum of each light-emitting device was measured using an optical measurement system that combined a spectrophotometer (PMA-12, manufactured by Hamamatsu Photonics K.K.) and an integrating sphere. The emission spectrum of each light-emitting device was measured at room temperature (20°C to 30°C). Figures 11 to 14 show the emission spectrum (spectral radiance) S(λ) of each light-emitting device. Figures 11 to 13 show the emission spectrum of each light-emitting device when the luminance L derived from the above formula (3) of each light-emitting device is set to the same numerical value. Figure 14 shows the emission spectrum of each light-emitting device and the emission spectrum of each light-emitting device when the radiance A derived from the above formula (5) of each light-emitting device is set to the same numerical value.

[0109] Chromaticity coordinates (x, y), correlated color temperature (K), color deviation Duv, average color rendering index Ra, special color rendering index R9, full width at half maximum From the emission spectrum of each light-emitting device, the chromaticity coordinates (x value, y value) on the CIE chromaticity diagram of CIE1931, the correlated color temperature (CCT:K) and color deviation Duv in accordance with JIS Z8725, and the average color rendering index Ra, special color rendering index R9, and full width at half maximum in accordance with JIS Z8726 were measured.

[0110] Ratio of second radiance to first radiance Lp From the emission spectrum (spectral radiance) S(λ) of each light-emitting device, the ratio Lp (%) of the second radiance in the range of 650 nm or more and 750 nm or less to the first radiance in the range of 400 nm or more and 750 nm or less, which is taken as 100%, was calculated based on the above formula (6).

[0111] 1st scattering index B / L The emission spectra (spectral radiance) S(λ) measured for each light-emitting device, the standard relative luminous efficacy curve V(λ) for human photopic vision defined by the CIE obtained from Figure 1, and the scattering intensity curve Dc(λ) for Rayleigh scattering versus wavelength when the scattering intensity of Rayleigh scattering at a wavelength of 300 nm is set to 1 obtained from Figure 2 were entered into the above formula (1) to calculate the first scattering index B / L for each light-emitting device.

[0112] First relative scattering index RS1 Among the light-emitting devices of Comparative Examples 1 and 2, which have a correlated color temperature exceeding 1950K and an average color rendering index Ra of 70 or more, the first scattering index of the light-emitting device of Comparative Example 1, which has the lowest first scattering index B / L, was set as the reference first scattering index B0 / L0. A first relative scattering index RS1, which is the ratio of the first scattering index B / L of each light-emitting device to the reference first luminance scattering index B0 / L0, was calculated based on formula (8).

[0113] Second scattering index B / A The emission spectra (spectral radiance) S(λ) measured for each light-emitting device and the scattering intensity curve Dc(λ) versus wavelength obtained from Figure 2, where the scattering intensity of Rayleigh scattering at a wavelength of 300 nm is set to 1, were entered into equation (2) to calculate the second scattering index B / A for each light-emitting device.

[0114] Second relative scattering index RS2 Among the light-emitting devices of Comparative Examples 1 and 2, which have a correlated color temperature exceeding 1950K and an average color rendering index Ra of 70 or more, the second luminance ratio of the light-emitting device of Comparative Example 2, which has the lowest second scattering index B / A, was set as the reference second scattering index B0 / A0. A second relative scattering index RS2, which is the ratio of the second scattering index B / A of each light-emitting device to the reference second scattering index B0 / A0, was calculated based on formula (10).

[0115] [Table 3]

[0116] As shown in Table 1, the light emitting devices according to Examples 1 to 4 have a correlated color temperature of 1950K or less, and emit light with a correlated color temperature that is similar to or slightly lower than that of light emitted by a high-pressure sodium lamp. The light emitting devices according to Examples 1 to 4 emit light that has a natural color tone and does not cause discomfort, even when used as a light source for a lamp used outdoors, instead of a high-pressure sodium lamp. In addition, the light emitting devices according to Examples 1 to 4 have a full width at half maximum of an emission peak having the maximum emission intensity in the emission spectrum within a range of 3 nm to 110 nm. In addition, the emission peak wavelength in the emission spectrum of the light emitting device is within a range of 570 nm to 680 nm. Since the full width at half maximum of an emission peak having the maximum emission intensity in the emission spectrum of the light emitting device is 3 nm to 110 nm, the light emitting device was able to suppress light components on the long wavelength side that are difficult for humans to sense. In addition, the light emitting devices according to Examples 1 to 3 emitted light with a first scattering index B / L of 0.151 or less, which was derived from the above formula (1) taking into account the standard luminous efficiency of human photopic vision. In addition, the light emitting device according to Example 4 emitted light with a second scattering index B / A of 0.060 or less, which was derived from the above formula (2), even without taking into account the standard luminous efficiency of human photopic vision.

[0117] The light emitting devices according to Examples 1 to 4 emitted light with a color deviation Duv, which is the deviation from the blackbody radiation locus, of 0.000. Even when the light emitting devices emitted light with a correlated color temperature of 1950K or less, the color of the irradiated object was natural and the light emitted by the light emitting devices did not cause discomfort to humans.

[0118] The light emitting devices according to Examples 1 to 4 emitted light in which the ratio Lp of the second radiance in the range of 650 nm to 750 nm to the first radiance of 100% in the range of 400 nm to 750 nm was 50% or less. The light emitting devices according to Examples 1 to 4 emitted light in which the red component was relatively small in the mixed color light emitted from the light emitting devices and which did not cause discomfort to humans.

[0119] The light emitting devices of Examples 1 to 3 emitted light that was more capable of suppressing scattering than light emitting devices that emitted light having a first relative scattering index RS1 of 98.5% or less, a correlated color temperature of more than 1950 K, and an average color rendering index Ra of 70 or more.

[0120] The light emitting device of Example 4 emitted light that had a second relative scattering index RS2 of 92.1%, a correlated color temperature of over 1950 K, and an average color rendering index Ra of 70 or more, and thus emitted light that was more capable of suppressing scattering than a light emitting device that emitted light.

[0121] The light emitting devices according to Examples 1 to 4 had an average color rendering index Ra of 70 or more, and emitted light with sufficient color rendering properties even in factories, offices, and schools where general work is performed.

[0122] The light emitting devices according to Comparative Examples 1 to 3 emit light with a correlated color temperature slightly higher than that of a high pressure sodium lamp, and when they are used as a light source for a lamp used outdoors instead of a high pressure sodium lamp, the color of the irradiated object may not look natural, which may cause a sense of incongruity. Furthermore, the light emitting devices according to Comparative Examples 1 to 3 emit light with a first scattering index B / L exceeding 0.151, and scattering was not suppressed when the standard relative luminous efficiency of human photopic vision was taken into consideration. Furthermore, the light emitting devices according to Comparative Examples 1 to 3 emit light with a second scattering index B / A exceeding 0.060, and scattering was not suppressed even when the standard relative luminous efficiency of human photopic vision was not taken into consideration.

[0123] As shown in Figures 11 to 13, the spectral radiance of the light-emitting devices according to Examples 1 to 3 was lower than that of the light-emitting device according to Comparative Example 1 in the range of 400 nm or more and 500 nm or less on the short wavelength side, where light is easily scattered by fine particles in the air.

[0124] As shown in FIG. 14, the spectral radiance of the light emitting device of Example 4 was lower than that of the light emitting device of Comparative Example 2 in the shorter wavelength range of 400 nm or more and 470 nm or less, where light is easily scattered by fine particles in the air. [Industrial Applicability]

[0125] The light-emitting device according to one embodiment of the present invention can be used as a light source for lighting devices intended for outdoor use, such as street lights that require light emission with reduced scattering, lighting devices installed outdoors in ports, tunnels, and the like, headlights, flashlights, and portable lanterns using LEDs, and also as a light source for lighting devices installed indoors in locations close to the outdoors, such as entrances and windows. [Explanation of symbols]

[0126] 1: support, 2: first lead, 3: second lead, 4: conductive member, 10: light-emitting element, 12p, 12n: electrodes, 21, 22, 23: wavelength conversion member, 30, 33: light-transmitting member, 32: light-transmitting joining member, 41: molded body, 42: resin part, 43: light-reflecting member, 44: covering member, 50: sealing member, 51: lens part, 52: flange part, 60: wire, 70: phosphor, 71: first phosphor, 72: second phosphor, 100, 200, 300, 400: light-emitting device, 1000: street light, C: roadway, Le: light source, P: pole, S: support part, T: light-transmitting part, W: sidewalk.

Claims

1. A light emitting element having an emission peak wavelength in the range of 400 nm to 490 nm; a first phosphor having an emission peak wavelength in the range of 570 nm to 680 nm, The light emitting device has a correlated color temperature of 1950K or less and an average color rendering index Ra of 70 or more; A light emitting device that emits light in which a first scattering index B / L of the effective radiance B relative to the luminance L, defined by the following formula (1), is 0.151 or less, where L is the luminance of the light emitted by the light emitting device in the range of 300 nm to 800 nm inclusive, taking into account the standard relative luminous efficiency of human photopic vision defined by CIE (International Commission on Illumination), and B is the effective radiance of the light emitted by the light emitting device in the range of 300 nm to 800 nm inclusive, taking into account a scattering intensity curve for wavelength when the scattering intensity of Rayleigh scattering at a wavelength of 300 nm is set to 1: (In formula (1), S(λ) is the spectral radiance of the light emitted by the light emitting device, V(λ) is the standard luminous efficiency curve for human photopic vision defined by the CIE (International Commission on Illumination), and Dc(λ) is the scattering intensity curve for wavelength when the scattering intensity of Rayleigh scattering at a wavelength of 300 nm is set to 1.)

2. A light emitting element having an emission peak wavelength in the range of 400 nm to 490 nm; a first phosphor having an emission peak wavelength in the range of 570 nm to 680 nm, The light emitting device has a correlated color temperature of 1950K or less and an average color rendering index Ra of 70 or more; When the radiance of the light emitted by the light emitting device in the range of 300 nm or more and 800 nm or less is A and the effective radiance of the light emitted by the light emitting device in the range of 300 nm or more and 800 nm or less is B, taking into account a scattering intensity curve for wavelength when the scattering intensity of Rayleigh scattering at a wavelength of 300 nm is set to 1, the light emitted has a second scattering degree index B / A of the effective radiance B relative to the radiance A, which is defined by the following formula (2), of 0.060 or less; A light emitting device that emits light having a first radiance of 100% in the range of 400 nm to 750 nm and a second radiance of 50% or less in the range of 650 nm to 750 nm. (In formula (2), S(λ) is the spectral radiance of the light emitted by the light emitting device, and Dc(λ) is a scattering intensity curve for wavelength when the scattering intensity of Rayleigh scattering at a wavelength of 300 nm is set to 1.)

3. 3 . The light emitting device according to claim 1 , wherein the first phosphor has an emission peak having an emission peak wavelength in an emission spectrum of the first phosphor, and a full width at half maximum of the emission peak is within a range of 3 nm to 120 nm.

4. The light emitting device according to any one of claims 1 to 3, wherein the first phosphor comprises at least one selected from the group consisting of a first nitride phosphor having a composition represented by the following formula (1A), a second nitride phosphor having a composition represented by the following formula (1B), a fluoride phosphor having a composition represented by the following formula (1C), and a fluoride phosphor having a composition represented by the following formula (1C') which has a different composition from that of formula (1C). M １ ２ Yes ５ N ８ :Eu (1A) (In formula (1A), M １ is an alkaline earth metal element including at least one selected from the group consisting of Ca, Sr, and Ba. Sr ｑ Ca ｓ Al ｔ Yes ｕ N ｖ :Eu (1B) (In formula (1B), q, s, t, u, and v respectively satisfy 0≦q<1, 0<s≦1, q+s≦1, 0.9≦t≦1.1, 0.9≦u≦1.1, and 2.5≦v≦3.5.) A ｃ [M ２ １－ｂ Mn ４＋ ｂ F ｄ ] (1C) (In formula (1C), A is K ＋ , Li ＋ , Na ＋ , Rb ＋ , Cs ＋ and N.H. ４ ＋ At least one selected from the group consisting of M ２ contains at least one element selected from the group consisting of Group 4 elements and Group 14 elements, b satisfies 0<b<0.2, and c satisfies [M ２ １－ｂ Mn ４＋ ｂ F ｄ ] is the absolute value of the charge of the ion, and d satisfies 5<d<7. A’ ｃ’ [M ２ ’ １－ｂ’ Mn ４＋ ｂ’ F ｄ’ ] (1C’) (In formula (1C'), A' is K ＋ , Li ＋ , Na ＋ , Rb ＋ , Cs ＋ and N.H. ４ ＋ At least one selected from the group consisting of M ２ b′ contains at least one element selected from the group consisting of Group 4 elements, Group 13 elements, and Group 14 elements, b′ satisfies 0<b′<0.2, and c′ satisfies [M ２ ' １－ｂ’ Mn ４＋ ｂ’ F ｄ’ ] is the absolute value of the charge of the ion, and d' satisfies 5<d'<7.

5. The light emitting device according to claim 1 , further comprising a second phosphor having an emission peak wavelength in the range of 480 nm to 570 nm.

6. The light emitting device according to claim 5 , wherein the second phosphor has an emission peak wavelength in an emission spectrum of the second phosphor, and a full width at half maximum of the emission peak is within a range of 20 nm to 125 nm.

7. 7. The light emitting device according to claim 5, wherein the second phosphor comprises at least one selected from the group consisting of a rare earth aluminate phosphor having a composition represented by the following formula (2A) and a third nitride phosphor having a composition represented by the following formula (2B): <h2 style=";text-align:left;direction:ltr">Ln<h2 style=";text-align:left;direction:ltr"> １ <h2 style=";text-align:left;direction:ltr"> ３ <h2 style=";text-align:left;direction:ltr"> ((Al<h2 style=";text-align:left;direction:ltr"> １－ａ <h2 style=";text-align:left;direction:ltr"> 8a<h2 style=";text-align:left;direction:ltr"> ａ <h2 style=";text-align:left;direction:ltr"> )<h2 style=";text-align:left;direction:ltr"> ５ <h2 style=";text-align:left;direction:ltr"> O<h2 style=";text-align:left;direction:ltr"> １２ <h2 style=";text-align:left;direction:ltr"> :Ce(22A) (In formula (2A), Ln １ is at least one element selected from the group consisting of Y, Gd, Tb and Lu, and a satisfies 0≦a≦0.

5. La ｗ Ln ２ ｘ Si ６ N ｙ :Ce ｚ (2) (In formula (2B), Ln ２ contains at least one selected from the group consisting of Y and Gd as an essential element, and may contain at least one selected from the group consisting of Sc and Lu, and Ln ２ When the element is 100 mol%, Ln ２ The total amount of Y and Gd contained in is 90 mol % or more, and w, x, y, and z satisfy 1.2≦w≦2.2, 0.5≦x≦1.2, 10≦y≦12, 0.5≦z≦1.2, 1.80<w+x<2.40, and 2.9≦w+x+z≦3.

1.

8. The light emitting device according to claim 5 , wherein a content of the first phosphor with respect to a total amount of the first phosphor and the second phosphor is within a range of 5 mass % to 95 mass %.

9. The light emitting device according to claim 1 , which emits light having a color deviation Duv from a blackbody radiation locus in the range of −0.008 to +0.

008.

10. The light emitting device according to claim 1 or any one of claims 3 to 9 which cites claim 1, emits light in which the second radiance in the range of 650 nm to 750 nm is 50% or less relative to the first radiance in the range of 400 nm to 750 nm of 100%.

11. A lamp comprising the light emitting device according to claim 1 .

12. A street lamp comprising the light emitting device according to any one of claims 1 to 10.

Images