Light-emitting device, lighting device, image display device, and display lamp for vehicle

Abstract

The present invention addresses the problem of providing a light-emitting device, an illumination device, an image display device, and / or a display lamp for a vehicle, the light-emitting device, the illumination device, the image display device, and / or the display lamp having excellent one or more of color rendering, color reproducibility, conversion efficiency, safety, and contrast. This light-emitting device is provided with a first light-emitting body and a second light-emitting body that emits visible light when irradiated with light from the first light-emitting body, and the second light-emitting body contains at least a red phosphor that satisfies (A) and (B) below. (A) the emission spectrum includes at least one emission peak having a full width at half maximum (FWHM) of 20-65 nm, and (B) the chromaticity coordinate of the emission color is present between two straight lines represented by formula (a) and formula (b) in a CIE1931 chromaticity coordinate system with the coordinate represented by (x, y) as a reference, and 0.290 < = y < = 0.350. Y is equal to 0.992-x... (a), and y is equal to 1.000-x... (b).

Description

Technical Field

[0001] The present invention relates to a light emitting device, a lighting device, an image display device and a display lamp for a vehicle. Background Art

[0002] In recent years, due to the trend of energy saving, the demand for light-emitting devices, lighting devices, image display devices and / or vehicle display lights using LEDs has been increasing. The LEDs used in such devices are, for example, white light-emitting LEDs in which a phosphor is arranged on an LED chip that emits light of a blue or near-ultraviolet wavelength.

[0003] As such a type of white light emitting LED, in recent years, an LED obtained by using a nitride phosphor that emits red light using blue light from the blue LED chip as excitation light and a phosphor that emits green light on a blue LED chip has been used. LEDs with high color rendering properties, color reproducibility and / or luminous efficiency are required.

[0004] The red phosphor included in the light emitting device is known to have a general formula of K2(Si,Ti)F6:Mn,K2Si 1－x Na x Al x F6: KSF phosphor represented by Mn (0<x<1) (for example, refer to non-patent document 1), S / CASN phosphor represented by the general formula (Sr, Ca)AlSiN3:Eu (for example, refer to patent document 1), 2-5-8 phosphor represented by the general formula Ca2Si5N8:Eu, etc. (for example, refer to non-patent document 2).

[0005] However, KSF phosphor is activated by Mn and is therefore harmful, and a phosphor that is less harmful to the human body and the environment is required. If considered from another perspective, as shown in FIG. 4 of Non-Patent Document 1, for example, the fluorescence decay time (DecayTime) of KSF phosphor is as long as several milliseconds (for example, refer to Non-Patent Document 1). This means that a lighting device equipped with KSF, especially a high-output device, may be luminance saturated and the conversion efficiency may be reduced, or an image display device (display) equipped with KSF may have a reduced contrast.

[0006] In addition, the full width at half maximum (hereinafter sometimes described as "spectral half-value width" or "A full width at half maximum" "FWHM") in the emission spectrum of S / CASN phosphors and 2-5-8 phosphors is relatively wide, about 80nm to 90nm (see, for example, Patent Document 1 and Non-Patent Document 2). Therefore, when these phosphors are mainly used as red light-emitting devices, for example, the emission intensity in the wavelength region of 700nm or more with low relative visibility often increases, and the conversion efficiency of luminous efficiency sometimes decreases.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2006-008721

[0010] Non-patent literature

[0011] Non-patent document 1: J. Mater. Chem. C, 2015, Vol. 3, Issue 21, p. 5484-5489

[0012] Non-patent document 2: Chemistry Letters, 2006, Vol. 35, No. 3, p. 334-335 Summary of the invention

[0013] In view of the above problems, an object of the present invention is to provide a light emitting device, a lighting device, an image display device and / or a vehicle indicator lamp having good color rendering performance, color reproducibility, conversion efficiency, safety and contrast from one point of view.

[0014] The inventors of the present invention have conducted in-depth research and found that a light-emitting device having at least a light source and a red phosphor, wherein the red phosphor includes a red phosphor whose chromaticity coordinates of the luminescent color are within a specific range, and the half-value width of the luminescent spectrum of the red phosphor is within a certain range can solve the above-mentioned problems, thereby completing the present invention. Some non-limiting embodiments are shown below. It should be noted that the present invention also includes embodiments that further have part or all of the features of one or more other embodiments relative to any of the embodiments shown below.

[0015] <1>: A light emitting device comprising a first light emitting body and a second light emitting body that emits visible light when irradiated with light from the first light emitting body, wherein the second light emitting body includes at least a red phosphor that satisfies the following (A) and (B).

[0016] (A) the emission spectrum includes at least one emission peak with a full width at half maximum (FWHM) of 20 nm to 65 nm,

[0017] (B) The chromaticity coordinates of the luminescent color are based on the coordinates represented by (x, y) in the CIE1931 chromaticity coordinate system, exist between two straight lines represented by the following formulas (a) and (b), and are 0.290≤y≤0.350.

[0018] y=0.992-x···(a)

[0019] y=1.000-x···(b)

[0020] <2>: The light emitting device according to <1> above, wherein a y value of a chromaticity coordinate of red light emitted by the red phosphor is greater than or equal to 0.300.

[0021] <3>: The light emitting device according to <1> or <2>, wherein the y value of the chromaticity coordinate of the red light emitted by the red phosphor is less than or equal to 0.310.

[0022] <4>: The light-emitting device according to any one of <1> to <3>, wherein the red phosphor includes a phosphor that does not substantially contain Mn.

[0023] <5>: The light-emitting device according to any one of <1> to <4>, wherein the light emission spectrum of the red phosphor includes at least one light emission peak having a light emission peak wavelength of 648 nm or less.

[0024] <6>: The light-emitting device according to any one of <1> to <5>, wherein the red phosphor has an internal quantum efficiency of 30% or more.

[0025] <7>: The light-emitting device according to any one of <1> to <6>, wherein the full width at half maximum of the light-emitting spectrum of the red phosphor is 57 nm or less.

[0026] <8>: The light emitting device according to any one of <1> to <7>, wherein the peak emission wavelength x (nm) and the half-width at half maximum y (nm) of the emission spectrum of the red phosphor satisfy the relationship y≤184-0.2x.

[0027] <9>: The light-emitting device according to any one of <1> to <8>, wherein the red phosphor includes at least a phosphor including a crystal phase having a composition represented by the following formula [1].

[0028] Re x MA a MB b MC cN d X e [1]

[0029] (In the above formula [1], MA contains one or more elements selected from Sr, Ca, Ba, Na, K, Y, Gd and La, MB contains one or more elements selected from Li, Mg and Zn, MC contains one or more elements selected from Al, Si, Ga, In and Sc, X contains one or more elements selected from F, Cl, Br and I, Re contains one or more elements selected from Eu, Ce, Pr, Tb and Dy, and a, b, c, d, e, and x satisfy the following formulas respectively.

[0030] 0.7≤a≤1.3

[0031] 0.7≤b≤1.3

[0032] 2.4≤c≤3.6

[0033] 3.2≤d≤4.8

[0034] 0.0≤e≤0.2

[0035] 0.0<x≤0.2)

[0036] <10>: The light-emitting device according to any one of <1> to <9>, wherein the red phosphor includes at least a phosphor including a crystal phase having a composition represented by the following formula [2].

[0037] Re x MA a MB b (MC' 1－y MD y ) c N d X e [2]

[0038] (In the above formula [2], MA contains one or more elements selected from Sr, Ca, Ba, Na, K, Y, Gd and La, MB contains one or more elements selected from Li, Mg and Zn, MC' is Al, MD contains one or more elements selected from Si, Ga, In and Sc, X contains one or more elements selected from F, Cl, Br and I, Re contains one or more elements selected from Eu, Ce, Pr, Tb and Dy, and a, b, c, d, e, x, y respectively satisfy the following formula.

[0039] 0.7≤a≤1.3

[0040] 0.7≤b≤1.3

[0041] 2.4≤c≤3.6

[0042] 3.2≤d≤4.8

[0043] 0.0≤e≤0.2

[0044] 0.0<x≤0.2

[0045] 0.0<y≤1.0)

[0046] <11>: The light-emitting device according to any one of <1> to <9>, wherein the red phosphor includes at least a phosphor including a crystal phase having a composition represented by the following formula [3].

[0047] Re x MA a MB b MC c (N, O) d X e [3]

[0048] (In the above formula [3], (N, O) means containing N and O, MA contains one or more elements selected from Sr, Ca, Ba, Na, K, Y, Gd and La, MB contains one or more elements selected from Li, Mg and Zn, MC contains one or more elements selected from Al, Si, Ga, In and Sc, X contains one or more elements selected from F, Cl, Br and I, Re contains one or more elements selected from Eu, Ce, Pr, Tb and Dy, and a, b, c, d, e, and x satisfy the following formulas respectively.

[0049] 0.7≤a≤1.3

[0050] 0.7≤b≤1.3

[0051] 2.4≤c≤3.6

[0052] 3.2≤d≤4.8

[0053] 0.0≤e≤0.2

[0054] 0.0<x≤0.2)

[0055] <12>: The light-emitting device according to any one of <1> to <8> and <10>, wherein the red phosphor includes at least a phosphor including a crystal phase having a composition represented by the following formula [4].

[0056] Re x MA a MB b (MC' 1－y MD y ) c (N, O)d X e [4]

[0057] (In the above formula [4], (N, O) means containing N and O, MA contains one or more elements selected from Sr, Ca, Ba, Na, K, Y, Gd and La, MB contains one or more elements selected from Li, Mg and Zn, MC' is Al, MD contains one or more elements selected from Si, Ga, In and Sc, X contains one or more elements selected from F, Cl, Br and I, Re contains one or more elements selected from Eu, Ce, Pr, Tb and Dy, and a, b, c, d, e, x, y respectively satisfy the following formulas.

[0058] 0.7≤a≤1.3

[0059] 0.7≤b≤1.3

[0060] 2.4≤c≤3.6

[0061] 3.2≤d≤4.8

[0062] 0.0≤e≤0.2

[0063] 0.0<x≤0.2

[0064] 0.0<y≤1.0)

[0065] <13>: The light emitting device according to any one of <1> to <12>, wherein the second light emitting body further includes a yellow phosphor and / or a green phosphor.

[0066] <14>: A light-emitting device according to any one of <1> to <13>, wherein the yellow phosphor and / or the green phosphor comprises at least one selected from a garnet phosphor, a silicate phosphor, a nitride phosphor and a nitride oxide phosphor.

[0067] <15>: A lighting device comprising the light-emitting device according to any one of <1> to <14> as a light source.

[0068] <16>: An image display device comprising the light emitting device according to any one of <1> to <14> as a light source.

[0069] <17>: A vehicle indicator lamp comprising the light emitting device according to any one of <1> to <14> as a light source.

[0070] <18>: A red phosphor that satisfies at least the following (A) and (B).

[0071] (A) the emission spectrum includes at least one emission peak with a full width at half maximum (FWHM) of 20 nm to 65 nm,

[0072] (B) The chromaticity coordinates of the luminescent color are based on the coordinates represented by (x, y) in the CIE1931 chromaticity coordinate system, exist between two straight lines represented by the following formulas (a) and (b), and are 0.290≤y≤0.350.

[0073] y=0.992-x···(a)

[0074] y=1.000-x···(b)

[0075] <19>: The red phosphor according to <18> above, wherein a y value of a chromaticity coordinate of red light is 0.300 or more.

[0076] <20>: The red phosphor according to <18> or <19>, wherein the y value of the chromaticity coordinates of red light is 0.310 or less.

[0077] <21>: The red phosphor according to any one of <18> to <20>, comprising a phosphor substantially free of Mn.

[0078] <22>: The red phosphor according to any one of <18> to <21>, wherein the emission spectrum includes at least one emission peak having a peak emission wavelength of 648 nm or less.

[0079] <23>: The red phosphor according to any one of <18> to <22>, wherein the internal quantum efficiency is 30% or more.

[0080] <24>: The red phosphor according to any one of <18> to <23>, wherein the full width at half maximum of the emission spectrum is 57 nm or less.

[0081] <25>: The red phosphor according to any one of <18> to <24>, wherein the emission peak wavelength x (nm) and the half-width at half maximum of the emission spectrum y (nm) satisfy the relationship y≤184-0.2x.

[0082] <26>: The red phosphor according to any one of <18> to <25>, comprising at least a phosphor including a crystal phase having a composition represented by the following formula [1].

[0083] Re x MA a MB b MC c N d X e [1]

[0084] (In the above formula [1], MA contains one or more elements selected from Sr, Ca, Ba, Na, K, Y, Gd and La, MB contains one or more elements selected from Li, Mg and Zn, MC contains one or more elements selected from Al, Si, Ga, In and Sc, X contains one or more elements selected from F, Cl, Br and I, Re contains one or more elements selected from Eu, Ce, Pr, Tb and Dy, and a, b, c, d, e, and x satisfy the following formulas respectively.

[0085] 0.7≤a≤1.3

[0086] 0.7≤b≤1.3

[0087] 2.4≤c≤3.6

[0088] 3.2≤d≤4.8

[0089] 0.0≤e≤0.2

[0090] 0.0<x≤0.2)

[0091] <27>: The red phosphor according to any one of <18> to <26>, comprising at least a phosphor including a crystal phase having a composition represented by the following formula [2].

[0092] Re x MA a MB b (MC' 1－y MD y ) c N d X e [2]

[0093] (In the above formula [2], MA contains one or more elements selected from Sr, Ca, Ba, Na, K, Y, Gd and La, MB contains one or more elements selected from Li, Mg and Zn, MC' is Al, MD contains one or more elements selected from Si, Ga, In and Sc, X contains one or more elements selected from F, Cl, Br and I, Re contains one or more elements selected from Eu, Ce, Pr, Tb and Dy, and a, b, c, d, e, x, y respectively satisfy the following formula.

[0094] 0.7≤a≤1.3

[0095] 0.7≤b≤1.3

[0096] 2.4≤c≤3.6

[0097] 3.2≤d≤4.8

[0098] 0.0≤e≤0.2

[0099] 0.0<x≤0.2

[0100] 0.0<y≤1.0)

[0101] <28>: The red phosphor according to any one of <18> to <26>, comprising at least a phosphor including a crystal phase having a composition represented by the following formula [3].

[0102] Re x MA a MB b MC c (N, O) d X e [3]

[0103] (In the above formula [3], (N, O) means containing N and O, MA contains one or more elements selected from Sr, Ca, Ba, Na, K, Y, Gd and La, MB contains one or more elements selected from Li, Mg and Zn, MC contains one or more elements selected from Al, Si, Ga, In and Sc, X contains one or more elements selected from F, Cl, Br and I, Re contains one or more elements selected from Eu, Ce, Pr, Tb and Dy, and a, b, c, d, e, and x satisfy the following formulas respectively.

[0104] 0.7≤a≤1.3

[0105] 0.7≤b≤1.3

[0106] 2.4≤c≤3.6

[0107] 3.2≤d≤4.8

[0108] 0.0≤e≤0.2

[0109] 0.0<x≤0.2)

[0110] <29>: The red phosphor according to any one of <18> to <26>, comprising at least a phosphor including a crystal phase having a composition represented by the following formula [4].

[0111] Re x MA a MB b (MC' 1－y MD y ) c (N, O) d X e [4]

[0112] (In the above formula [4], (N, O) means containing N and O, MA contains one or more elements selected from Sr, Ca, Ba, Na, K, Y, Gd and La, MB contains one or more elements selected from Li, Mg and Zn, MC' is Al, MD contains one or more elements selected from Si, Ga, In and Sc, X contains one or more elements selected from F, Cl, Br and I, Re contains one or more elements selected from Eu, Ce, Pr, Tb and Dy, and a, b, c, d, e, x, y respectively satisfy the following formulas.

[0113] 0.7≤a≤1.3

[0114] 0.7≤b≤1.3

[0115] 2.4≤c≤3.6

[0116] 3.2≤d≤4.8

[0117] 0.0≤e≤0.2

[0118] 0.0<x≤0.2

[0119] 0.0<y≤1.0)

[0120] The present invention can provide a light emitting device, an illumination device, an image display device and / or a vehicle indicator lamp with good color rendering performance, color reproducibility, conversion efficiency, safety and contrast in various embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0121] Figure 1 This is a graph in which the colors of the samples of phosphors 2 to 9 used in the respective examples and phosphors 1 and 10 used in comparative examples 1 to 6 are plotted with reference to the coordinates represented by (x, y) in the CIE chromaticity coordinates.

[0122] Figure 2A This is a graph showing the emission intensities of phosphors 2 to 5 when the emission intensity of phosphor 1 at its emission peak wavelength is set to 1.

[0123] Figure 2B This is a graph showing the emission intensities of phosphors 6 to 10 when the emission intensity of phosphor 1 at the emission peak wavelength is set to 1.

[0124] Figure 3 This is a graph showing relative emission intensities when the emission intensities at the emission peak wavelengths of the reference phosphor and phosphors 1, 2, 5, 8, and 9 are respectively set to 1.

[0125] Figure 4AThe graph shows the CIE chromaticity coordinates (0.437, 0.404) and the simulation results of the relative luminous intensity of the white LEDs of Comparative Example 1, Example 1, and Example 2 at a color temperature of 3000K.

[0126] Figure 4B The diagram shows the CIE chromaticity coordinates (0.437, 0.404) and the simulation results of the relative luminous intensity of the white LEDs of Comparative Examples 3 and 4 and Examples 3 and 4 at a color temperature of 3000K.

[0127] Figure 4C The graph shows the CIE chromaticity coordinates (0.437, 0.404) and the simulation results of the relative luminous intensity of the white LEDs of Comparative Example 1, Example 5, and Example 6 at a color temperature of 3000K.

[0128] Figure 4D The graph shows the CIE chromaticity coordinates (0.437, 0.404) and the simulation results of the relative luminous intensity of the white LEDs of Comparative Example 1, Example 7, and Example 15 at a color temperature of 3000K.

[0129] Figure 5A It is a diagram showing the simulation results of relative luminous intensity when the luminous intensity at the luminous peak wavelength of the white LED of Comparative Example 1 and Comparative Example 4 at a color temperature of 3000K and Examples 1 and 2 is set to 1 respectively.

[0130] Figure 5B It is a graph showing the simulation results of relative luminous intensity when the luminous intensity at the luminous peak wavelength of the white LED of Comparison Example 1, Comparison Example 3 and Comparison Example 4 at a color temperature of 3000K with CIE chromaticity coordinates (0.437, 0.404) is set to 1.

[0131] Figure 5C It is a diagram showing the simulation results of relative luminous intensity when the luminous intensity at the luminous peak wavelength of the white LED of Comparative Example 1 and Comparative Example 4 at a color temperature of 3000K and Examples 5 and 6 is set to 1 respectively.

[0132] Figure 5D It is a graph showing the simulation results of relative luminous intensity when the luminous intensity at the luminous peak wavelength of the white LEDs of Reference Example 1, Comparative Example 4, and Examples 7 and 15 at a color temperature of 3000K with CIE chromaticity coordinates (0.437, 0.404) is set to 1.

[0133] Figure 5EIt is a diagram showing the simulation results of relative luminous intensity when the luminous intensity at the luminous peak wavelength of the white LED of Reference Example 1, and Examples 3 and 7 at a color temperature of 3000K is set to 1.

[0134] Fig. 6A The graph shows the CIE chromaticity coordinates (0.380, 0.377) and the simulation results of the relative luminous intensity of the white LEDs of Comparative Example 2, Example 8, and Example 9 at a color temperature of 4000K.

[0135] Figure 6B The graph shows the CIE chromaticity coordinates (0.380, 0.377) and the simulation results of the relative luminous intensity of the white LEDs of Comparative Examples 5 and 6, and Examples 10 and 11 at a color temperature of 4000K.

[0136] Figure 6C The graph shows the CIE chromaticity coordinates (0.380, 0.377) and the simulation results of the relative luminous intensity of the white LEDs of Comparative Example 2, Example 12, and Example 13 at a color temperature of 4000K.

[0137] Fig.6D The diagram shows the CIE chromaticity coordinates (0.380, 0.377) and the simulation results of the relative luminous intensity of the white LEDs of Comparative Example 2, Example 14, and Example 16 at a color temperature of 4000K.

[0138] Fig. 7A It is a graph showing the simulation results of relative luminous intensity when the luminous intensity at the luminous peak wavelength in the region of 500nm to 780nm of the white LEDs of Comparative Examples 2 and 6 at a color temperature of 4000K and Examples 8 and 9 is set to 1.

[0139] Figure 7B It is a graph showing the simulation results of relative luminous intensity when the luminous intensity at the luminous peak wavelength in the range of 500nm to 780nm of the white LEDs of Comparison Example 2, Comparison Example 5 and Comparison Example 6 at a color temperature of 4000K is set to 1.

[0140] Figure 7C It is a graph showing the simulation results of relative luminous intensity when the luminous intensity at the luminous peak wavelength in the range of 500nm to 780nm of the white LEDs of Comparison Example 2 and Comparison Example 6 at a color temperature of 4000K with CIE chromaticity coordinates (0.380, 0.377) and Example 12 and Example 13 is set to 1.

[0141] Fig.7D It is a graph showing the simulation results of relative luminous intensity when the luminous intensity at the luminous peak wavelength in the range of 500nm to 780nm of the white LEDs of Reference Example 2, Comparative Example 6, and Examples 14 and 16 at a color temperature of 4000K with CIE chromaticity coordinates (0.380, 0.377) is set to 1.

[0142] Fig. 7E It is a graph showing the simulation results of relative luminous intensity when the luminous intensity at the luminous peak wavelength in the range of 500nm to 780nm of the white LEDs of Reference Example 2, Examples 10 and 14 at a color temperature of 4000K with CIE chromaticity coordinates (0.380, 0.377) is set to 1. DETAILED DESCRIPTION

[0143] Hereinafter, the present invention will be described by showing embodiments and examples, but the present invention is not limited to the following embodiments and examples, and can be implemented with arbitrary modifications within the scope not departing from the gist of the present invention.

[0144] It should be noted that the numerical range represented by “~” in this specification indicates a range that includes the numerical values ​​recorded before and after “~” as the lower limit and upper limit. In addition, in the composition formula of the phosphor in this specification, the division of each composition formula is represented by a comma (,). In addition, when multiple elements are listed and separated by a comma (,), it means that one or more of the listed elements can be contained in any combination and composition. For example, a composition formula such as “(Ca, Sr, Ba)Al2O4:Eu” generally represents all of the following: “CaAl2O4:Eu”, “SrAl2O4:Eu”, “BaAl2O4:Eu”, “Ca 1－x Sr x Al2O4:Eu", "Sr 1－ x Ba x Al2O4:Eu", "Ca 1－x Ba x Al2O4:Eu", and "Ca 1－x－y Sr x Ba y Al2O4:Eu" (wherein, 0<x<1, 0<y<1, 0<x+y<1).

[0145] In one embodiment, the present invention is a light-emitting device comprising a first light-emitting body and a second light-emitting body that emits visible light when irradiated with light from the first light-emitting body, wherein the second light-emitting body includes at least a red phosphor that satisfies the following (A) and (B).

[0146] In another embodiment, the present invention is a red phosphor including a red phosphor satisfying the following (A) and (B).

[0147] (A) the emission spectrum includes at least one emission peak with a full width at half maximum (FWHM) of 20 nm to 65 nm,

[0148] (B) The chromaticity coordinates of the luminescent color are based on the coordinates represented by (x, y) in the CIE1931 chromaticity coordinate system, exist between two straight lines represented by the following formulas (a) and (b), and are 0.290≤y≤0.350.

[0149] y=0.992-x···(a)

[0150] y=1.000-x···(b)

[0151] From another point of view, the present invention, in one embodiment, is a light-emitting device comprising a first light-emitting body and a second light-emitting body that emits visible light when irradiated with light from the first light-emitting body, wherein the second light-emitting body includes at least a red phosphor that satisfies the following (A) and (C).

[0152] In another embodiment, the present invention is a red phosphor including a red phosphor satisfying the following (A) and (C).

[0153] (A) the emission spectrum includes at least one emission peak with a full width at half maximum (FWHM) of 20 nm to 65 nm,

[0154] (C) The chromaticity coordinates of the red light emitted by the above-mentioned red phosphor are located in the area enclosed by four vertices, point A (0.710, 0.290), point B (0.650, 0.350), point C (0.642, 0.350) and point D (0.702, 0.290), based on the coordinates represented by (x, y) in the CIE1931 chromaticity coordinate system.

[0155] In one embodiment, the x+y value of the chromaticity coordinates of the red light emitted by the red phosphor is generally 0.992 to 1.000. In another embodiment, it may be greater than 0.992, may be greater than 0.994 or 0.996, or may be less than 1.000 or less than 0.999.

[0156] In one embodiment, the value of y in the chromaticity coordinates of the red light emitted by the red phosphor is preferably 0.340 or less, more preferably 0.330 or less, further preferably 0.320 or less, particularly preferably 0.310 or less, and particularly preferably 0.300 or less. When the value of y in the chromaticity coordinates is less than the upper limit, a light-emitting device having good red color rendering or color reproducibility can be provided, which is suitable for use in image display devices (displays), for example.

[0157] The above-mentioned embodiment can also be expressed as follows. That is, for example, in the embodiment in which the value of y is less than 0.340, the chromaticity coordinates of the red light emitted by the above-mentioned red phosphor are located in the area surrounded by four vertices, point A (0.710, 0.290), point E (0.660, 0.340), point F (0.652, 0.340) and point D (0.702, 0.290) based on the coordinates represented by (x, y) in the CIE1931 chromaticity coordinate system. In the embodiment in which the upper limit value of y is changed, the y values ​​at points E and F can be set to the changed upper limit values, and the x value of point E is replaced by [1-the upper limit value of y after the change], and the x value of point F is replaced by [0.992-the upper limit value of y after the change].

[0158] In another embodiment, the value of y in the chromaticity coordinates of the red light emitted by the red phosphor is preferably 0.295 or more, more preferably 0.300 or more, further preferably 0.310 or more, and particularly preferably 0.315 or more. When the value of y in the chromaticity coordinates is greater than the lower limit, a light-emitting device having high relative visibility in the red region and good conversion efficiency can be provided, which is suitable for lighting applications, for example.

[0159] The above-mentioned embodiment can also be expressed as follows. That is, for example, in the embodiment in which the value of y is greater than 0.295, the chromaticity coordinates of the red light emitted by the above-mentioned red phosphor are located in the area surrounded by four vertices, point G (0.705, 0.295), point B (0.650, 0.350), point C (0.642, 0.350) and point H (0.697, 0.295) based on the coordinates represented by (x, y) in the CIE1931 chromaticity coordinate system. In the embodiment in which the lower limit value of y is changed, the values ​​of y at points G and H can be respectively set to the changed lower limit values, and the value of x at point G can be replaced by [1-the lower limit value of y after the change], and the value of x at point H can be replaced by [0.992-the lower limit value of y after the change].

[0160] In one embodiment, the red phosphor included in the light emitting device includes a phosphor that does not substantially contain Mn. In a specific embodiment, the red phosphor consists only of a phosphor that does not substantially contain Mn.

[0161] By partially or entirely using a red phosphor that is substantially free of Mn, that is, the red phosphor includes a phosphor that is substantially free of Mn, a light-emitting device that reduces or eliminates harmful Mn compounds and is friendly to the human body and the environment can be provided.

[0162] It should be noted that in this specification, a phosphor that "does not substantially contain" a specific component means that the elements constituting the crystal phase of the phosphor do not contain the specific component, and the specific component is not added as an additive element, activator, etc. A phosphor that "does not substantially contain" a specific component allows a trace amount of the specific component to be unintentionally mixed in the form of impurities, etc.

[0163] <Red phosphor>

[0164] In one embodiment, the red phosphor includes at least a phosphor including a crystal phase having a composition represented by the following formula [1].

[0165] Re x MA a MB b MC c N d X e [1]

[0166] (In the above formula [1], MA contains one or more elements selected from Sr, Ca, Ba, Na, K, Y, Gd and La, MB contains one or more elements selected from Li, Mg and Zn, MC contains one or more elements selected from Al, Si, Ga, In and Sc, X contains one or more elements selected from F, Cl, Br and I, Re contains one or more elements selected from Eu, Ce, Pr, Tb and Dy, and a, b, c, d, e, and x satisfy the following formulas respectively.

[0167] 0.7≤a≤1.3

[0168] 0.7≤b≤1.3

[0169] 2.4≤c≤3.6

[0170] 3.2≤d≤4.8

[0171] 0.0≤e≤0.2

[0172] 0.0<x≤0.2)

[0173] In formula [1], Re can be europium (Eu), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm) and ytterbium (Yb). From the viewpoint of improving the emission wavelength and the emission quantum efficiency, Re preferably contains one or more elements selected from Eu, Ce, Pr, Tb and Dy, more preferably contains Eu, further preferably 80 mol% or more of Re is Eu, and further preferably Re is Eu.

[0174] In formula [1], MA contains one or more elements selected from calcium (Ca), strontium (Sr), barium (Ba), sodium (Na), potassium (K), yttrium (Y), gadolinium (Gd) and lanthanum (La), preferably contains one or more elements selected from Ca, Sr and Ba, and more preferably MA contains Sr. In addition, preferably, 80 mol% or more of MA is composed of the above preferred elements, and more preferably MA is composed of the above preferred elements.

[0175] In formula [1], MB contains one or more elements selected from lithium (Li), magnesium (Mg) and zinc (Zn), preferably contains Li, more preferably 80 mol % or more of MB is Li, and even more preferably MB is Li.

[0176] In formula [1], MC contains one or more elements selected from aluminum (Al), silicon (Si), gallium (Ga), indium (In) and scandium (Sc), preferably contains Al, Ga or Si, more preferably contains one or more elements selected from Al and Ga, further preferably 80 mol% or more of MC is composed of one or more elements selected from Al and Ga, particularly preferably 90 mol% or more of MC is composed of one or more elements selected from Al and Ga, and most preferably MC is composed of one or more elements selected from Al and Ga.

[0177] In one embodiment, 80 mol% or more of MC is Al, preferably 90 mol% or more, more preferably 95 mol% or more, and further preferably 98 mol% or more. When 80 mol% or more of MC is Al, a red phosphor having a light emission peak wavelength and light emission intensity equivalent to those of existing red phosphors such as S / CASN and a narrow spectral half-value width can be provided, and a light emitting device having such a red phosphor maintains a conversion efficiency (Conversion Efficiensy, Lm / W) equivalent to or higher than that of the conventional one, and has good color rendering or color reproducibility.

[0178] In formula [1], N represents nitrogen. In order to maintain the charge balance of the entire crystal phase or to adjust the emission peak wavelength, a part of N may be substituted with oxygen (O).

[0179] In formula [1], X includes one or more elements selected from fluorine (F), chlorine (Cl), bromine (Br) and iodine (I). That is, in a specific embodiment, from the viewpoint of maintaining the stabilization of the crystal structure and the charge balance of the phosphor as a whole, a portion of N may be substituted by the above-mentioned halogen element represented by X.

[0180] The above formula [1] includes the case where components other than those explicitly described are contained in trace amounts inevitably or unintentionally.

[0181] As components other than those explicitly described, there can be cited elements that differ by one element number from the artificially added element, elements of the same group as the artificially added element, rare earth elements different from the artificially added rare earth elements, halogen elements when halides are used as raw materials, and elements that may generally be contained as impurities in various raw materials.

[0182] In this specification, "artificially adding" a specific component means intentionally adding the specific component as an element constituting the composition of the crystalline phase of the phosphor. The case where a trace amount of the specific component is accidentally mixed in the form of impurities does not constitute "intentional addition". A phosphor to which a specific component is artificially added can be said to substantially contain the specific component.

[0183] As the case where components other than those clearly described are inevitably or unintentionally contained, for example, impurities from raw materials and the case where they are introduced in the production process such as the pulverization step and the synthesis step can be considered. In addition, as trace added components, reaction aids and raw materials can be mentioned.

[0184] In the above formula [1], a, b, c, d, e, and x represent the molar contents of MA, MB, MC, N, X, and Re contained in the phosphor, respectively.

[0185] The value of a is usually 0.6 or more, preferably 0.7 or more, more preferably 0.8 or more, and even more preferably 0.9 or more, and is usually 1.4 or less, preferably 1.3 or less, more preferably 1.2 or less, and even more preferably 1.1 or less.

[0186] The value of b is usually 0.6 or more, preferably 0.7 or more, more preferably 0.8 or more, and even more preferably 0.9 or more, and is usually 1.4 or less, preferably 1.3 or less, more preferably 1.2 or less, and even more preferably 1.1 or less.

[0187] The value of c is usually 2.1 or more, preferably 2.4 or more, more preferably 2.6 or more, and even more preferably 2.8 or more, and is usually 3.9 or less, preferably 3.6 or less, more preferably 3.4 or less, and even more preferably 3.2 or less.

[0188] The value of d is usually 3 or more, preferably 3.2 or more, more preferably 3.4 or more, further preferably 3.6 or more, further preferably 3.8 or more, and usually 5 or less, preferably 4.8 or less, more preferably 4.6 or less, further preferably 4.4 or less, further preferably 4.2 or less.

[0189] The value of e is not particularly limited, but is usually 0 or more, usually 0.2 or less, preferably 0.1 or less, more preferably 0.06 or less, further preferably 0.04 or less, and further preferably 0.02 or less.

[0190] The value of x is usually greater than 0, preferably greater than 0.0001, more preferably greater than 0.001, and usually less than 0.2, preferably less than 0.15, more preferably less than 0.12, further preferably less than 0.1, and further preferably less than 0.08. When the value of x is greater than or equal to the above lower limit, a phosphor with good luminous intensity can be obtained. When the value of x is less than the above upper limit, a phosphor in which Re is well introduced into the crystal and easily functions as a luminescent center can be obtained. By having such a red phosphor, a light-emitting device with good conversion efficiency can be provided.

[0191] When b, c, d, and e are within the above ranges, the crystal structure is stabilized. In addition, the values ​​of d and e can be appropriately adjusted to maintain the charge balance of the entire phosphor.

[0192] In addition, by setting the value of a within the above range, the crystal structure is stabilized and a phosphor with less heterophase can be obtained. By having such a red phosphor, a light-emitting device with good absorption efficiency of excitation light and good red and overall conversion efficiency can be provided.

[0193] The value of b+c is usually 3.1 or more, preferably 3.4 or more, more preferably 3.7 or more, and is usually 4.9 or less, preferably 4.6 or less, more preferably 4.3 or less.

[0194] When the value of b+c is within the above range, the crystal structure is stabilized.

[0195] The value of d+e is usually 3.2 or more, preferably 3.4 or more, more preferably 3.7 or more, and is usually 5.0 or less, preferably 4.6 or less, more preferably 4.3 or less.

[0196] When the value of d+e is within the above range, the crystal structure is stabilized.

[0197] If any of the values ​​are within the above ranges, the emission peak wavelength and the half-value width of the emission spectrum of the obtained red phosphor are good, which is preferable from this point of view.

[0198] The elemental composition of the red phosphor may be determined by any conventional method, for example, GD-MS, ICP spectrometry, or energy dispersive X-ray spectrometry (EDX).

[0199] In one embodiment, the red phosphor includes at least a phosphor including a crystal phase having a composition represented by the following formula [2].

[0200] Re x MA a MB b (MC' 1－y MD y ) c N d X e [2]

[0201] (In the above formula [2], MA contains one or more elements selected from Sr, Ca, Ba, Na, K, Y, Gd and La, MB contains one or more elements selected from Li, Mg and Zn, MC' is Al, MD contains one or more elements selected from Si, Ga, In and Sc, X contains one or more elements selected from F, Cl, Br and I, Re contains one or more elements selected from Eu, Ce, Pr, Tb and Dy, and a, b, c, d, e, x, y respectively satisfy the following formula.

[0202] 0.7≤a≤1.3

[0203] 0.7≤b≤1.3

[0204] 2.4≤c≤3.6

[0205] 3.2≤d≤4.8

[0206] 0.0≤e≤0.2

[0207] 0.0<x≤0.2

[0208] 0.0<y≤1.0)

[0209] The types and compositions of the elements MA, MB, N, X, and Re in the above formula [2] may be the same as those in the above formula [1].

[0210] The above MC' is Al.

[0211] The MD contains one or more elements selected from Si, Ga, In and Sc, and preferably contains one or more elements selected from Ga and Si, and more preferably contains Ga, from the viewpoint of improving crystal stability and light emission intensity.

[0212] In a more preferred specific embodiment, 80 mol % or more of MD is Ga, and MD may be composed of Ga.

[0213] The values ​​and preferred ranges of a, b, c, d, e and x in the above formula [2] may be the same as those in the above formula [1].

[0214] The value of y in the above formula [2] is greater than 0.0, usually 0.01 or more, preferably 0.015 or more, more preferably 0.03 or more, further preferably 0.05 or more, particularly preferably 0.10 or more, and usually 1.00 or less, preferably 0.70 or less, more preferably 0.50 or less, further preferably 0.30 or less, particularly preferably 0.25 or less.

[0215] When the value of y is greater than or equal to the above lower limit, the peak wavelength of the emission of the phosphor is shortened, and by using such a red phosphor, a light-emitting device with good color rendering or color reproducibility can be provided. In addition, when the value of y is less than or equal to the above upper limit, a phosphor with good emission intensity can be obtained, and by using such a red phosphor, a light-emitting device with good conversion efficiency can be provided. The value of y can be appropriately adjusted to obtain a preferred emission intensity and peak wavelength according to the purpose.

[0216] When a part of N in formula [1] or formula [2] is substituted with oxygen (O), formula [1] can be replaced with the following formula [3], and formula [2] can be replaced with the following formula [4].

[0217] Re x MA a MB b MC c (N, O) d X e [3]

[0218] Re x MA a MB b (MC' 1－y MD y ) c (N, O) d X e [4]

[0219] In formula [3] and [4], (N, O) means containing N and O, and Re, MA, MB, MC, MC', MD, X, x, y, a, b, c, d, and e are all the same as those in formula [1] or [2].

[0220] The ratio of N (nitrogen) in the (N, O) site can be adjusted arbitrarily, preferably 50 mol% or more, more preferably 70 mol% or more, and further preferably 80 mol% or more. By properly adjusting the ratio of N (nitrogen) in (N, O), the charge balance of the entire crystalline phase can be maintained, or the luminescence peak wavelength can be adjusted.

[0221] In addition, all the descriptions about formula [1] or formula [2] in this specification can also be applied to formula [3] or formula [4].

[0222] [Particle size of crystal phase]

[0223] The particle size of the crystalline phase of the red phosphor in this embodiment is generally 2 μm to 40 μm in terms of the volume-based central particle size (volume median particle size), and the lower limit is preferably 3 μm, more preferably 4 μm, and further preferably 5 μm. In addition, the upper limit is preferably 35 μm, more preferably 30 μm, further preferably 25 μm, and particularly preferably 20 μm.

[0224] If the volume-based central particle size (volume median particle size) is above the above lower limit, the luminescent characteristics displayed by the crystalline phase in the LED package are improved, which is preferred from this point of view. If it is below the above upper limit, the crystalline phase can avoid nozzle clogging in the manufacturing process of the LED package, which is preferred from this aspect.

[0225] The volume-based central particle diameter (volume median particle diameter) of the crystalline phase of the phosphor can be measured using a measurement technique known to those skilled in the art. In a preferred embodiment, for example, a laser particle size analyzer can be used for measurement. In the embodiments of this specification, the volume-based central particle diameter (volume median particle diameter, (d 50 )) is defined as the particle size at which the relative particle amount on a volume basis reaches 50% when the particle size distribution (cumulative distribution) is determined by measuring the sample using a particle size distribution measuring device using the laser diffraction scattering method as the measurement principle.

[0226] {Physical properties of red phosphor, etc.}

[0227] [Space Group]

[0228] The crystal system (space group) of the red phosphor of this embodiment is not limited as long as the effect of the present invention can be obtained. In a specific embodiment, it is preferably P-1. The space group of the red phosphor of this embodiment is not particularly limited as long as the average structure obtained by statistical research within the range that can be distinguished by X-ray powder diffraction or single crystal X-ray diffraction shows a repetition period of the above length. It is preferably a space group belonging to the second type based on "International Tables for Crystallography (Third, revised edition), Volume ASPACE-GROUP SYMMETRY".

[0229] By using the above space group, a red phosphor having a narrowed full width at half maximum (FWHM) of the emission spectrum and good emission efficiency can be obtained.

[0230] Here, the space group can be determined by a conventional method, for example, by using electron diffraction, X-ray diffraction structure analysis of powder or single crystal, neutron diffraction structure analysis, or the like.

[0231] For the red phosphor of the present embodiment, in a specific embodiment, the intensity of the peak appearing in the region of 2θ=38 to 39 degrees in the X-ray powder diffraction pattern is set to Ix, and the intensity of the peak appearing in the region of 2θ=37 to 38 degrees is set to Iy. When Iy is set to 1, the relative intensity of Ix, i.e., Ix / Iy, is preferably less than 0.140, more preferably less than 0.120, further preferably less than 0.110, further preferably less than 0.080, particularly preferably less than 0.060, and particularly preferably less than 0.040. In addition, it is usually greater than 0, and the smaller the better.

[0232] The peak in the region of 2θ=37 to 38 degrees is one of the characteristic peaks of the main phase of the red phosphor of this embodiment. When Iy is relatively high, a red phosphor with higher phase purity can be obtained. When Ix / Iy is below the above upper limit, a phosphor with high phase purity and narrow half-value width (FWHM) of the emission spectrum can be obtained, thereby improving the luminous efficiency of the light-emitting device.

[0233] [Internal quantum efficiency of red phosphor]

[0234] In one embodiment, the internal quantum efficiency of the red phosphor is 30% or more. The internal quantum efficiency is preferably 35% or more, more preferably 40% or more, further preferably 45% or more, particularly preferably 50% or more, and particularly preferably 55% or more. There is no upper limit, the higher the better, and it is usually 100% or less.

[0235] The internal quantum efficiency of a red phosphor can be obtained by a conventional method, for example, it can be calculated from a light emission spectrum measured using a spectrophotometer.

[0236] [Characteristics of luminescence spectrum]

[0237] The red phosphor of this embodiment is excited by irradiating light having an appropriate wavelength, and emits red light showing a good luminescence peak wavelength and a half-maximum full width (FWHM) of the luminescence spectrum. The above-mentioned luminescence spectrum and excitation wavelength, luminescence peak wavelength and half-maximum full width (FWHM) of the luminescence spectrum are described below.

[0238] (Excitation wavelength)

[0239] The red phosphor of this embodiment has an excitation peak in a wavelength range of usually 270 nm or more, preferably 300 nm or more, more preferably 320 nm or more, further preferably 350 nm or more, particularly preferably 400 nm or more, and usually 550 nm or less, preferably 520 nm or less, more preferably 500 nm or less. That is, it is excited by light in the near-ultraviolet to blue region.

[0240] It should be noted that the shape of the luminescence spectrum, as well as the following description of the luminescence peak wavelength and the half-width of the luminescence spectrum can be applied independently of the excitation wavelength. From the perspective of improving quantum efficiency, it is preferred to irradiate light with a wavelength in the above range with good absorption and excitation efficiency.

[0241] (Emission peak wavelength)

[0242] In one embodiment, the emission spectrum of the red phosphor includes at least one emission peak whose emission peak wavelength is generally 620 nm to 660 nm.

[0243] In a specific embodiment, the emission spectrum of the red phosphor includes at least one emission peak preferably at 625 nm or more, more preferably at 630 nm or more, further preferably at 635 nm or more, further preferably at 640 nm or more, and extremely preferably at 645 nm or more. A light-emitting device having a red phosphor including at least one emission peak having an emission peak wavelength greater than the above lower limit has good color rendering properties or color reproducibility of red, and is suitable for applications such as backlights for image display devices (displays). Alternatively, it can emit bright red light, and is suitable for applications such as brake lights.

[0244] In another specific embodiment, the luminescence spectrum preferably contains at least one luminescence peak below 655 nm, more preferably below 650 nm, further preferably below 648 nm, further preferably below 645 nm, particularly preferably below 640 nm, and extremely preferably below 637 nm. A red phosphor having a luminescence spectrum containing at least one luminescence peak below the upper limit has low luminescence intensity in a wavelength region near 700 nm where relative visibility is low, and a light-emitting device having such a red phosphor has good conversion efficiency, and is suitable for use in, for example, lighting devices.

[0245] There is no particular limitation on the method for adjusting the above-mentioned peak emission wavelength. For example, by adjusting the composition of the MC elements, the peak emission wavelength can be adjusted while keeping the half-maximum full width of the emission spectrum narrow. In a specific embodiment, the peak emission wavelength can be adjusted to the long wavelength side by increasing the proportion of Al in MC. In addition, the peak emission wavelength can be adjusted to the short wavelength side by increasing the proportion of elements other than Al in a part of MC in the above formula [1] or the proportion of MD elements in the formula [2].

[0246] (Full width at half maximum of the luminescence spectrum)

[0247] The full width at half maximum of the emission spectrum of the red phosphor of this embodiment is usually less than 70nm, preferably less than 65nm, more preferably less than 60nm, further preferably less than 57nm, particularly preferably less than 55nm, most preferably less than 50nm, and is usually greater than 10nm.

[0248] By using a red phosphor whose emission spectrum has a full width at half maximum within the above range, it is possible to expand the color reproduction range without reducing color purity in an image display device such as a liquid crystal display.

[0249] In addition, by making the emission peak wavelength and the half-width of the emission spectrum below the above-mentioned upper limits, a red phosphor with relatively high visual sensitivity in the emission wavelength region can be provided, and by using such a red phosphor in a light-emitting device, a light-emitting device with high conversion efficiency can be provided.

[0250] It should be noted that, in order to excite the above-mentioned red phosphor with light having a wavelength of about 450nm, for example, a GaN-based LED can be used. In addition, the measurement of the emission spectrum of the above-mentioned red phosphor, and the calculation of its emission peak wavelength, peak relative intensity and half-maximum full width of the emission spectrum can be performed using, for example, a commercially available spectrum measuring device such as a fluorescence measuring device equipped with a commercially available xenon lamp or other light source having an emission wavelength of 300 to 400nm and a general light detector.

[0251] In one embodiment of the above-mentioned light-emitting device, the peak wavelength x (nm) of the light emission of the red phosphor and the full width at half maximum y (nm) of the light emission spectrum satisfy the relationship y≤184-0.2x.

[0252] By using a phosphor whose emission peak wavelength and half-width at half maximum satisfy the above formula, the conversion efficiency of the light-emitting device can be improved.

[0253] <Method for producing phosphor>

[0254] The phosphor of this embodiment can be synthesized by mixing raw materials of the elements constituting the phosphor so that the ratio of the elements satisfies the above formula [1] or formula [2], and heating the mixture.

[0255] [Phosphor raw materials]

[0256] The phosphor raw material as the supply source of each element (MA, MB, MC, MC', Re) is not particularly limited, and examples thereof include single substances, oxides, nitrides, hydroxides, chlorides, halides such as fluorides, inorganic salts such as sulfates, nitrates, phosphates, organic acid salts such as acetates, etc. of each element. In addition, compounds containing two or more of the above-mentioned element groups can also be used. In addition, each compound can also be a hydrate, etc.

[0257] In addition, in the examples described below, nitrides of the elements other than Re are used, and fluoride or oxide of the Re element is used as a phosphor raw material.

[0258] The method for obtaining each phosphor raw material is not particularly limited, and commercially available raw materials can be purchased and used.

[0259] There is no particular restriction on the purity of each phosphor raw material. From the perspective of making the element ratio accurate and avoiding the appearance of heterogeneous phases due to impurities, the higher the purity, the better. It is usually above 90 mol%, preferably above 95 mol%, more preferably above 97 mol%, and further preferably above 99 mol%. There is no particular restriction on the upper limit, which is usually below 100 mol%. It may contain impurities that are inevitably mixed in.

[0260] In the examples described below, a phosphor raw material having a purity of 95 mol % or more is used.

[0261] In addition to being supplied by using oxides, nitrides, halides, etc. of phosphor raw materials as supply sources of the above elements, oxygen (O), nitrogen (N) and halogen elements (X) can also be appropriately contained in the atmosphere during the synthesis reaction by using oxygen or nitrogen.

[0262] [Mixing process]

[0263] The mixing method of the phosphor raw materials is not particularly limited, and conventional methods can be used. For example, the phosphor raw materials are weighed in a manner to obtain a target composition, and are fully mixed using a ball mill or the like to obtain a phosphor raw material mixture. The above-mentioned mixing method is not particularly limited, and specifically, the following methods (a) and (b) can be cited.

[0264] (a) A dry mixing method in which the above-mentioned phosphor raw materials are ground and mixed by a combination of grinding using a dry pulverizer such as a hammer mill, roller mill, ball mill, jet mill, or mortar and pestle, and mixing using a mixer such as a spiral mixer, V-type mixer, Henschel mixer, or mortar and pestle.

[0265] (b) A wet mixing method in which a solvent or dispersion medium such as water is added to the above-mentioned phosphor raw material, and the mixture is mixed using, for example, a grinder, a mortar and pestle, or an evaporating dish and a stirring rod to form a solution or slurry, and then dried by spray drying, heat drying, natural drying, or the like.

[0266] The phosphor raw materials may be mixed by either the dry mixing method or the wet mixing method. In order to avoid contamination of the phosphor raw materials by water, the dry mixing method or the wet mixing method using a water-insoluble solvent is preferably used.

[0267] In addition, the method (a) was adopted in the Examples described later.

[0268] [Heating process]

[0269] In the heating step (hereinafter sometimes referred to as the calcining step), for example, the phosphor raw material mixture obtained in the mixing step is placed in a crucible and then heated at a temperature of 500° C. to 1200° C. The temperature in the heating step is preferably 600° C. or higher, more preferably 700° C. or higher, preferably 1000° C. or lower, more preferably 950° C. or lower, and may be 900° C. or lower.

[0270] By setting the heating temperature (hereinafter sometimes referred to as the calcination temperature) to a low temperature, particularly 950°C or lower, a phosphor having a composition represented by formula [1] with high phase purity and high luminous intensity can be obtained. The reason for this is that at high temperatures such as 1000°C or higher, 1100°C or higher, substances such as Li, Mg, and Na with high vapor pressures tend to volatilize, and the ratio of each element tends to change during the synthesis reaction of the phosphor. Conversely, by performing the synthesis at a low temperature such as 950°C or lower, the change in the ratio of each element can be suppressed.

[0271] In addition, the pressure of the heating process can be either normal pressure or pressurized state as long as the target phosphor can be obtained. In order to prevent the volatilization of elements contained in the phosphor raw material, it is preferably pressurized. When pressurized, the pressure is usually 0.1MPa to 200MPa, preferably below 100MPa. By keeping the pressure in the above range, good reactivity of the phosphor raw material can be ensured.

[0272] The pressurization method is not limited, and for example, a method of heating the sealed container, a method of mechanically pressurizing, a method of utilizing gas pressure, etc. can be used.

[0273] The material of the crucible is preferably a material that does not react with the phosphor raw material or reactant, and examples include ceramics such as alumina, quartz, boron nitride, silicon carbide, silicon nitride, and metals such as nickel (Ni), platinum (Pt), molybdenum (Mo), tungsten (W), tantalum (Ta), niobium (Nb), iridium (Ir), rhodium (Rh), or alloys with these as the main components.

[0274] The heating is preferably performed in an inert atmosphere, and a gas having nitrogen, argon, helium or the like as a main component can be used.

[0275] In addition, in the Examples described below, heating was performed under a nitrogen atmosphere.

[0276] In the heating process, heating is performed in the above-mentioned temperature range for usually 10 minutes to 200 hours, preferably 1 hour to 100 hours, and more preferably 2 hours to 50 hours. In addition, the above-mentioned heating process can be performed once or multiple times. As a method of dividing the heating process into multiple times, there can be cited a method including an annealing process for heating under pressure to repair defects, a method of performing secondary heating to obtain secondary particles or a final product after a primary heating of a primary particle or an intermediate, etc.

[0277] In this way, the phosphor of this embodiment can be obtained.

[0278] <Light-emitting device>

[0279] In one embodiment, the present invention is a light emitting device including a first light emitting body and a second light emitting body that emits visible light when irradiated with light from the first light emitting body.

[0280] The second light-emitting body includes at least a red phosphor satisfying the following (A) and (B).

[0281] (A) the emission spectrum includes at least one emission peak with a full width at half maximum (FWHM) of 20 nm to 65 nm,

[0282] (B) The chromaticity coordinates of the luminescent color exist between two straight lines represented by the following formula (a) and formula (b) based on the CIE1931 chromaticity coordinate system, and are 0.290≤y≤0.350.

[0283] y=0.992-x···(a)

[0284] y=1.000-x···(b)

[0285] In another embodiment, the present invention is a light-emitting device comprising at least a red phosphor as the second light-emitting body, wherein the red phosphor comprises a crystalline phase having a composition represented by the above formula [1] or [2]. Here, the second light-emitting body may be a single phosphor or two or more phosphors may be used in any combination and ratio.

[0286] The light-emitting device in this embodiment may further use a yellow phosphor that generates yellow fluorescence when irradiated with light from an excitation light source, a green phosphor that generates green fluorescence, or a red phosphor that generates red region (orange or red) fluorescence (a red phosphor that does not satisfy at least one of the above (A) and (B)) in addition to having at least a red phosphor that satisfies the above (A) and (B) as the second light-emitting body.

[0287] In a specific embodiment, the light-emitting device of the present invention is a light-emitting device in which the second light-emitting body further includes a yellow phosphor and / or a green phosphor.

[0288] Specifically, when constituting a light-emitting device, as a yellow phosphor, it is preferred that the phosphor has a luminescence peak in a wavelength range of 550 nm to 600 nm, and as a green phosphor, it is preferred that the phosphor has a luminescence peak in a wavelength range of 500 nm to 560 nm. In addition, the orange or red phosphor has a luminescence peak in a wavelength range of usually 615 nm or more, preferably 620 nm or more, more preferably 625 nm or more, further preferably 630 nm or more, and usually 660 nm or less, preferably 650 nm or less, more preferably 645 nm or less, and further preferably 640 nm or less.

[0289] By appropriately combining the phosphors in the above wavelength regions, a light-emitting device showing excellent color reproducibility can be provided. It should be noted that the excitation light source may have an emission peak in a wavelength range of less than 420 nm.

[0290] Hereinafter, although a mode of the light-emitting device using a phosphor satisfying at least the above (A) and (B) as a red phosphor is described, the present embodiment is not limited thereto.

[0291] In the above case, the light emitting device of this embodiment may be in the following form (X), (Y) or (Z), for example.

[0292] (X) A method comprising a first light-emitting body and a second light-emitting body, wherein the second light-emitting body includes a red phosphor that at least satisfies the above-mentioned (A) and (B), and at least one phosphor (yellow phosphor) having a light emission peak in the wavelength range of 550nm to 600nm.

[0293] (Y) A method comprising a first light-emitting body and a second light-emitting body, wherein the second light-emitting body includes a red phosphor that at least satisfies the above-mentioned (A) and (B), and at least one phosphor (green phosphor) having a light emission peak in the wavelength range of 500nm to 560nm.

[0294] (Z) A method comprising a first light-emitting body and a second light-emitting body, wherein the second light-emitting body includes a red phosphor satisfying at least the above-mentioned (A) and (B), and at least one phosphor (yellow phosphor) having a light-emitting peak in a wavelength range of 550nm to 600nm, and at least one phosphor (green phosphor) having a light-emitting peak in a wavelength range of 500nm to 560nm.

[0295] As the yellow phosphor and / or green phosphor in the above-mentioned embodiment, commercially available phosphors can be used, for example, garnet phosphors, silicate phosphors, nitride phosphors, oxynitride phosphors, etc. In a specific embodiment, the yellow phosphor and / or green phosphor includes any one or more selected from garnet phosphors, silicate phosphors, nitride phosphors, and oxynitride phosphors.

[0296] (Yellow phosphor)

[0297] As the garnet-based phosphor that can be used as the yellow phosphor, for example, (Y, Gd, Lu, Tb, La)3(Al, Ga)5O 12 :(Ce, Eu, Nd), as silicate phosphors, for example, (Ba, Sr, Ca, Mg)2SiO4:(Eu, Ce), as nitride phosphors and oxynitride phosphors, for example, (Ba, Ca, Mg)Si2O2N2:Eu (SION phosphors), (Li, Ca)2(Si, Al) 12 (O, N) 16 :(Ce, Eu)(α-sialon phosphor), (Ca, Sr)AlSi4(O, N)7:(Ce, Eu)(1147 phosphor), (La, Ca, Y, Gd)3(Al, Si)6N 11 :(Ce, Eu)(LSN phosphor), etc.

[0298] These may be used alone or in combination of two or more.

[0299] As the yellow phosphor, garnet-based phosphors are preferred among the above phosphors, and among them, Y3Al5O 12 : YAG-based phosphor represented by Ce.

[0300] (Green phosphor)

[0301] As garnet-based phosphors that can be used as green phosphors, for example, (Y, Gd, Lu, Tb, La)3(Al, Ga)5O 12 (Ce, Eu, Nd), Ca3(Sc, Mg)2Si3O 12 :(Ce, Eu) (CSMS phosphor), as silicate phosphor, for example, (Ba, Sr, Ca, Mg)3SiO 10 :(Eu, Ce), (Ba, Sr, Ca, Mg)2SiO4:(Ce, Eu)(BSS phosphor), as oxide phosphors, for example, (Ca, Sr, Ba, Mg)(Sc, Zn)2O4:(Ce, Eu)(CASO phosphor), as nitride phosphors and oxynitride phosphors, for example, (Ba, Sr, Ca, Mg)Si2O2N2:(Eu, Ce), Si 6－z Al z O z N 8－z :(Eu, Ce)(β-sialon phosphor)(0<z≤1),(Ba, Sr, Ca, Mg, La)3(Si, Al)6O 12 N2: (Eu, Ce) (BSON phosphor), (La, Ca, Y, Gd)3(Al, Si)6N 11 :(Ce, Eu)(LSN phosphor), etc.

[0302] These may be used alone or in combination of two or more.

[0303] (Red phosphor)

[0304] As the red phosphor, the phosphor of the present embodiment that satisfies at least the above (A) and (B) is used, but other orange or red phosphors such as garnet phosphors, sulfide phosphors, nanoparticle phosphors, nitride phosphors, and oxynitride phosphors may be used in addition to the phosphors of the present embodiment. As other orange or red phosphors, for example, the following phosphors may be used.

[0305] Examples of sulfide phosphors include (Sr, Ca)S:Eu (CAS phosphor) and La2O2S:Eu (LOS phosphor). Examples of garnet phosphors include (Y, Lu, Gd, Tb)3Mg2AlSi2O3 and (Y, Lu, Gd, Tb)3Mg2AlSi2O4.12 :Ce, as nanoparticles, for example, CdSe can be cited, as nitride or oxynitride phosphors, for example, (Sr, Ca)AlSiN3:Eu (S / CASN phosphor), (CaAlSiN3) 1－x ·(SiO2N2) x :Eu(CASON phosphor),(La,Ca)3(Al,Si)6N 11 :Eu(LSN phosphor),(Ca,Sr,Ba)2Si5(N,O)8:Eu(258 phosphor),(Sr,Ca)Al 1+x Si 4－x O x N 7－x :Eu(1147 phosphor), M x (Si, Al) 12 (O, N) 16 : Eu (M is Ca, Sr, etc.) (α-sialon phosphor), Li (Sr, Ba) Al3N4: Eu (the above x is 0<x<1), etc.

[0306] These may be used alone or in combination of two or more.

[0307] [Configuration of light emitting device]

[0308] The light-emitting device of this embodiment can have a first light-emitting body (excitation light source) and use a red phosphor that at least satisfies the above (A) and (B) as a second light-emitting body. Its structure is not limited and any known device structure can be adopted.

[0309] As the first light-emitting body, an LED element in which a light-emitting structure is formed in various semiconductors such as GaN-based semiconductors, ZnO-based semiconductors, and SiC-based semiconductors can be used.

[0310] As an embodiment of the device configuration and the light emitting device, for example, there can be cited the embodiment described in Japanese Patent Application Laid-Open No. 2007-291352.

[0311] In addition, the LED element can be fixed in a package such as a shell-type package, an SMD-type package, or can be directly fixed on a circuit substrate as in a chip-on-board type light-emitting device. The optical combination of the LED element and the phosphor is not limited to a method, and the two can be filled with only a transparent medium (including air), or optical elements such as lenses, optical fibers, light guide plates, and reflectors can be sandwiched between the two. The structure in which the phosphor particles are dispersed in a translucent matrix is ​​typically formed by curing a resin paste in which particulate phosphors are dispersed. In addition to the structure in which the solidified material of such a paste is embedded in the LED element, various structures such as a structure in which the solidified material covers a part of the surface of the LED element in a film-like shape, a structure in which the film composed of the solidified material is arranged at a position away from the LED element, etc. can also be used.

[0312] {Purpose of the light-emitting device}

[0313] The use of the light emitting device is not particularly limited, and the light emitting device can be used in various fields in which light emitting devices are generally used. Among them, a light emitting device with high color rendering index can be particularly suitably used as a light source for a lighting device or an image display device.

[0314] Furthermore, a light emitting device including a red phosphor having a good light emission wavelength can also be used for a red vehicle indicator lamp or a vehicle indicator lamp emitting white light including the red light.

[0315] [lighting device]

[0316] In one embodiment, the present invention may be a lighting device including the above-mentioned light-emitting device as a light source.

[0317] When the light emitting device is applied to a lighting device, the specific structure of the lighting device is not limited, as long as the light emitting device described above is appropriately assembled in a known lighting device for use. For example, a surface emitting lighting device having a plurality of light emitting devices arranged on the bottom surface of a holding housing can be cited.

[0318] [Image display device]

[0319] In one embodiment, the present invention may be an image display device including the above-mentioned light-emitting device as a light source.

[0320] When the above-mentioned light-emitting device is used as a light source of an image display device, the specific structure of the image display device is not limited, and it is preferably used together with a color filter. For example, when a color image display device using a color liquid crystal display element is made as an image display device, the image display device can be formed by using the above-mentioned light-emitting device as a backlight and combining a light shutter using liquid crystal with a color filter having red, green, and blue pixels.

[0321] [Vehicle indicator lights]

[0322] In one embodiment, the present invention may be a vehicle indicator lamp including the above-mentioned light emitting device as a light source.

[0323] In a specific embodiment, the light emitting device used in the vehicle indicator lamp is preferably a light emitting device that radiates white light. The light emitting device that radiates white light preferably has a color deviation duv (also called Δuv) of -0.0200 to 0.0200 from the black body radiation locus and a color temperature of 5000K to 30000K.

[0324] In a specific embodiment, the light emitting device used in the vehicle indicator lamp is preferably a light emitting device that radiates red light. In this embodiment, for example, the light emitting device can absorb blue light irradiated from a blue LED chip and emit red light, thereby providing a red vehicle indicator lamp.

[0325] Vehicle indicator lights include the vehicle's headlights, position lights, taillights, signal lights, brake lights, fog lights, etc., which are used to provide any indication to other vehicles, pedestrians, etc.

[0326] Example

[0327] Hereinafter, some specific embodiments of the present invention will be described by way of examples, but the present invention is not limited to the following contents unless it departs from the gist of the present invention.

[0328] {Measurement method}

[0329] [Measurement of luminescence spectrum]

[0330] The emission spectrum was measured using a fluorescence spectrophotometer FP8500 (manufactured by JASCO Corporation) under the following measurement conditions.

[0331] Light source: Xenon lamp

[0332] Excitation wavelength: 455nm

[0333] ·Measurement wavelength range: 380~780nm

[0334] ·Measurement interval: 1.0nm

[0335] The chromaticity coordinates are calculated from the emission spectrum data of 480 nm to 780 nm using the CIE1931 XYZ equation function.

[0336] [Quantum efficiency measurement]

[0337] The quantum efficiency was calculated based on the emission spectrum measured by a fluorescence spectrophotometer FP8500 (manufactured by JASCO Corporation) under the following measurement conditions.

[0338] Light source: Xenon lamp

[0339] Excitation wavelength: 455nm

[0340] ·Measurement wavelength range: 380~780nm

[0341] ·Measurement interval: 1.0nm

[0342] [Phosphor coordination simulation]

[0343] Based on the measured information on the excitation emission spectrum, internal quantum efficiency and absorption efficiency of the excitation light of each phosphor, a white spectrum is virtually created that satisfies specific chromaticity coordinate points when the spectrum of a blue LED chip emitting 449nm light is combined with an arbitrary phosphor, and a simulation is performed to estimate the phosphor combination ratio at that time.

[0344] Based on the obtained white spectrum, the light beam (Lm) per unit energy (Wopt) of the luminous spectrum, that is, the spectral efficiency (LER) and the color rendering indexes of R1 to R15 are calculated.

[0345] <Manufacturing of phosphor>

[0346] [Phosphor 1]

[0347] An exemplary red phosphor used in a light-emitting device according to one embodiment of the present invention or a comparative example is manufactured.

[0348] Refer to Japanese Patent Publication No. 2017-008130 and Chemistry of Materials 2019 31(12), 4614-4618, etc., the nitrides of the elements were mixed in a ratio of Sr:Li:Al of approximately 1:1:3, placed in a boron nitride crucible, the container was sealed, and then heated at 1000°C for 5 hours in a nitrogen atmosphere to obtain phosphor 1.

[0349] [Phosphors 2 to 9]

[0350] Phosphors 2 to 9 were obtained in the same manner as in Phosphor 1 except that a nitride raw material containing Ga appropriately was used so that the composition of the phosphor became the composition shown in Table 1 and the calcination temperature was 845°C.

[0351] [Phosphor 10]

[0352] Phosphor 10 was obtained in the same manner as Phosphor 1 except that a nitride raw material containing Ga was used so that the composition of the phosphor was the composition shown in Table 1 and the calcination temperature was 1020° C. The properties of Phosphors 1 to 10 are shown in Table 1. In Table 1, the relative emission intensity describes a relative value when the emission intensity of Phosphor 1 is set to 1.

[0353] Figure 1 2 shows a graph in which the emission colors of the samples of phosphors 1 to 10 are plotted with reference to the coordinates represented by (x, y) in the CIE chromaticity coordinates.

[0354] It is known that phosphors 1 and 10 are red phosphors that do not satisfy condition (B) because their CIE chromaticity coordinates do not lie between the two straight lines represented by equations (a) and (b). On the other hand, it is known that phosphors 2 to 9 are red phosphors that satisfy condition (A) and (B).

[0355] [Table 1]

[0356]

[0357] exist Figure 2A to Figure 2B 2 shows the relationship between the emission intensity and wavelength of phosphors 1 to 10.

[0358] Depend on Figure 2A to Figure 2B It can be seen that the emission intensities of phosphors 2 to 9 are significantly improved compared to phosphors 1 and 10.

[0359] In addition, Figure 3 The normalized emission spectra of the above phosphors and a CASN phosphor (BR-101 / J manufactured by Mitsubishi Chemical Corporation) with an emission peak wavelength of 646 nm as a reference phosphor are shown in FIG. Figure 3 It can be seen that the phosphor of the present invention has a good luminescence spectrum with a narrow half-value width, and phosphors 5, 8 and 9 have a shorter luminescence peak wavelength than phosphor 1.

[0360] It should be noted that the powder X-ray diffraction patterns of phosphors 1 to 10 all showed good consistency with SrLiAl 3 N 4 .

[0361] <Comparative Example 1, Comparative Examples 3 to 4, Examples 1 to 7, Example 15>

[0362] Under the assumption that the SCASN phosphor (Mitsubishi Chemical Corporation, BR2 / 620) with a peak emission wavelength of 620nm, which does not satisfy both (A) and (B) above, is used as the first red phosphor, the phosphors shown in Table 1 as the second red phosphor, and the LuAG phosphor (Mitsubishi Chemical Corporation, BG-801 / B4) as the green phosphor, the emission spectrum of the white LED having each phosphor is derived based on the emission spectrum, internal quantum efficiency (iQE) and other information of each phosphor. All simulations are performed assuming a blue LED chip emitting 449nm light. Furthermore, in order to confirm whether a light emission spectrum that satisfies one of the typical specifications required for white LEDs and has good conversion efficiency is obtained, all simulations were performed with the average color rendering evaluation index Ra being 90 or more and the red color rendering evaluation index R9 being 50 or more, and the amounts of the green phosphor and the first and second red phosphors being adjusted so that the CIE chromaticity coordinates coincide with the coordinates (0.437, 0.404) of 3000K white light on the Planck curve, and the characteristics were compared.

[0363] The simulation results of the relative luminous intensity of the white LEDs of Comparative Examples 1, 3 to 4 and Examples 1 to 7 and 15 are shown in FIG. Figure 4A to Figure 4D The simulation results of the relative luminous intensity when the luminous intensity at the luminous peak wavelength of each white LED is 1 are shown in Figure 5A to Figure 5E In addition, the average color rendering index Ra, the red color rendering index R9, and the light beam (Lm) per unit energy (Wopt) of the luminous spectrum, i.e., the spectral efficiency (LER), which is an indicator of conversion efficiency, are obtained from each spectrum and are shown in Table 2.

[0364] <Comparative Example 2, Comparative Examples 5 to 6, Examples 8 to 14, Example 16>

[0365] Comparative Examples 2, 5 to 6 and Examples 8 to 14 and 16 were simulated in the same manner as in Comparative Example 1 and Examples 1 to 7 except that the CIE chromaticity coordinates were made consistent with the coordinates (0.380, 0.377) of 4000K white light on the Planck curve.

[0366] The simulation results of the relative luminous intensity of the white LEDs of Comparative Examples 2, 5 to 6 and Examples 8 to 14 and 16 are shown in FIG. Figure 6A to Figure 6D The simulation results of the relative luminous intensity when the luminous intensity at the luminous peak wavelength of each white LED in the wavelength range of 500nm to 780nm is 1 are shown in FIG. Figure 7A to Figure 7E Table 3 shows the results of obtaining the average color rendering evaluation index Ra, the red color rendering evaluation index R9, and the spectral efficiency (LER) from each spectrum.

[0367] It should be noted that the "ratio / wt%" of the phosphors in Tables 2 and 3 refers to the weight ratio of each phosphor when the total weight of each phosphor is set to 100%, "Green" is the above-mentioned LuAG phosphor, "Red 1" is the above-mentioned first red phosphor, and "Red 2" is the above-mentioned second red phosphor.

[0368] [Table 2]

[0369]

[0370] [Table 3]

[0371]

[0372] In the specifications of Ra≥90 and R9≥50, the spectral efficiency LER of Examples 1 to 7 and 15 is significantly improved compared with Comparative Example 1, and that of Examples 8 to 14 and 16 is significantly improved compared with Comparative Example 2.

[0373] Note that, in Comparative Examples 1 and 2 using phosphor 1 whose chromaticity coordinates do not satisfy the requirements of the present invention, a large amount of second red phosphor is required to satisfy Ra and correlated color temperature, and R9 becomes higher than necessary, whereas LER is low.

[0374] In contrast, in Examples 1 and 8 using phosphor 2, the required R9 was successfully secured and LER was improved. This effect was further significant in Examples 3 to 9 using phosphors 3 to 9 having a peak emission wavelength of less than 650 nm as red phosphor 2.

[0375] From another point of view, according to Figure 5A and Fig. 7A It can be seen that the example corresponding to the embodiment of the present invention includes the red and green regions in a well-balanced manner compared to Comparative Examples 1 and 2, and as a result, the spectral efficiency is improved.

[0376] In addition, according to Figure 5C It can be seen that the example equivalent to the implementation mode of the present invention successfully ensures R9 by having a preferred luminous intensity in the red region compared with the example such as Comparative Example 4, and improves LER by suppressing the luminous intensity in the wavelength region above 660nm with relatively low visibility compared with Comparative Example 1, thereby obtaining a light-emitting device with good color rendering and conversion efficiency. Fig. 7A and Figure 7C By comparing Comparative Examples 2 and 6 with each embodiment, it can be seen that the same effect is obtained even in luminescent colors showing different correlated color temperatures.

[0377] When phosphor 10 was used, combinations of phosphors of various modes were tried, but no emission spectrum satisfying Ra≥90 and R9≥50 could be obtained.

[0378] As typical patterns, the cases where a large amount of phosphor 10 is used are shown as Comparative Examples 3 and 5, and the cases where a red phosphor is not used much and a green phosphor is used exclusively are shown as Comparative Examples 4 and 6.

[0379] Calculated, the color rendering index R9 of red is always negative, but this cannot be considered an accurate value, but means that the color rendering index of red is too low to be accurately calculated.

[0380] <Reference Example 1>

[0381] A simulation was performed in the same manner as in Example 1 except that a CASN phosphor having a light emission peak wavelength of 646 nm (BR-101 / J manufactured by Mitsubishi Chemical Corporation) was used instead of the second red phosphor.

[0382] Figure 5D to Figure 5E 2 shows a graph in which the relative luminous intensity in Reference Example 1 and the relative luminous intensity in each example are normalized.

[0383] In addition, Table 2 shows various characteristics of the white LED of Reference Example 1.

[0384] <Reference Example 2>

[0385] A simulation was performed in the same manner as in Example 8 except that a CASN phosphor having a peak emission wavelength of 646 nm (BR-101 / J manufactured by Mitsubishi Chemical Corporation) was used instead of the second red phosphor.

[0386] Figure 7D to Figure 7E Graphs showing normalized relative emission intensities in Reference Example 2 and in each Example when the maximum emission intensity in the wavelength region of 480 nm to 780 nm is set to 1 are shown.

[0387] As is clear from these figures, the light-emitting device of the present invention has a sharp peak in the red region and can suppress the emission intensity in the wavelength region above 680nm where visibility is relatively low, thereby providing a light-emitting device with high color rendering or red color reproducibility and high conversion efficiency.

[0388] As shown above, according to the present embodiment, a phosphor having a good luminous peak wavelength, a narrow half-maximum full width of the luminous spectrum and / or a high luminous intensity can be provided. In addition, by having the phosphor, a light-emitting device, a lighting device, an image display device and / or a vehicle display lamp having good color rendering or color reproduction and good conversion efficiency can be provided.

[0389] Although various embodiments have been described above with reference to the accompanying drawings, the present invention is certainly not limited to the above examples. For those skilled in the art, various variations or modifications can be thought of within the scope of the claimed scope, and this is clear, and it can be understood that they certainly also belong to the technical scope of the present invention. In addition, the various constituent elements in the above embodiments can be arbitrarily combined within the scope of the invention without departing from the gist of the invention.

[0390] Although various embodiments have been described above, the present invention is certainly not limited to the above examples. For those skilled in the art, various variations or modifications can be thought of within the scope of the claimed scope, and this is clear, and it can be understood that they certainly also belong to the technical scope of the present invention. In addition, the various constituent elements in the above embodiments can be arbitrarily combined within the scope of the invention without departing from the gist of the invention.

[0391] It should be noted that the present application is based on the Japanese patent application (Japanese Patent Application No. 2022-210188) filed on December 27, 2022, and the contents thereof are incorporated herein by reference.

[0392] Industrial Applicability

[0393] The light emitting device of the present invention has excellent color rendering, color reproducibility, conversion efficiency, safety, and contrast, and therefore can be used in lighting devices, image display devices, vehicle indicator lights, and the like.

Claims

1. A light-emitting device comprising a first light-emitting body and a second light-emitting body that emits visible light when irradiated with light from the first light-emitting body, wherein the second light-emitting body at least includes a red phosphor that satisfies the following (A) and (B), (A) the emission spectrum includes at least one emission peak with a full width at half maximum (FWHM) of 20 nm to 65 nm, (B) The chromaticity coordinates of the luminescent color are based on the coordinates represented by (x, y) in the CIE1931 chromaticity coordinate system, exist between two straight lines represented by the following formulas (a) and (b), and are 0.290≤y≤0.350, y=0.992-x···(a) y=1.000-x···(b).

2. The light emitting device according to claim 1, wherein: The y value of the chromaticity coordinate of red light emitted by the red phosphor is greater than or equal to 0.

300.

3. The light emitting device according to claim 1 or 2, wherein: The y value of the chromaticity coordinate of red light emitted by the red phosphor is less than or equal to 0.

310.

4. The light emitting device according to claim 1 or 2, wherein: The red phosphor includes a phosphor that does not substantially contain Mn.

5. The light emitting device according to claim 1 or 2, wherein: The light emission spectrum of the red phosphor includes at least one light emission peak having a light emission peak wavelength of 648 nm or less.

6. The light emitting device according to claim 1 or 2, wherein: The internal quantum efficiency of the red phosphor is greater than 30%.

7. The light emitting device according to claim 1 or 2, wherein: The full width at half maximum of the emission spectrum of the red phosphor is less than 57 nm.

8. The light emitting device according to claim 1 or 2, wherein: The peak emission wavelength x and the half-maximum full width y of the emission spectrum of the red phosphor satisfy the relationship of y≤184-0.2x, and the units of the peak emission wavelength x and the half-maximum full width y are nm.

9. The light emitting device according to claim 1 or 2, wherein: The red phosphor at least includes: a phosphor including a crystal phase having a composition represented by the following formula [1], Re x MA a MB b MC c N d X e [1] In the formula [1], MA contains one or more elements selected from Sr, Ca, Ba, Na, K, Y, Gd and La, MB contains one or more elements selected from Li, Mg and Zn, MC contains one or more elements selected from Al, Si, Ga, In and Sc, X contains one or more elements selected from F, Cl, Br and I, Re contains one or more elements selected from Eu, Ce, Pr, Tb and Dy, and a, b, c, d, e, and x respectively satisfy the following formula: 0.7≤a≤1.3 0.7≤b≤1.3 2.4≤c≤3.6 3.2≤d≤4.8 0.0≤e≤0.2 0.0＜x≤0.2。 10. The light emitting device according to claim 1 or 2, wherein: The red phosphor at least includes: a phosphor including a crystal phase having a composition represented by the following formula [2], Re x MA a MB b (MC' 1－y MD y ) c N d X e [2] In the formula [2], MA contains one or more elements selected from Sr, Ca, Ba, Na, K, Y, Gd and La, MB contains one or more elements selected from Li, Mg and Zn, MC' is Al, MD contains one or more elements selected from Si, Ga, In and Sc, X contains one or more elements selected from F, Cl, Br and I, Re contains one or more elements selected from Eu, Ce, Pr, Tb and Dy, and a, b, c, d, e, x and y respectively satisfy the following formula: 0.7≤a≤1.3 0.7≤b≤1.3 2.4≤c≤3.6 3.2≤d≤4.8 0.0≤e≤0.2 0.0＜x≤0.2 0.0＜y≤1.0。 11. The light emitting device according to claim 1 or 2, wherein: The red phosphor at least includes: a phosphor including a crystal phase having a composition represented by the following formula [3], Re x MA a MB b MC c (N, O) d X e [3] In the formula [3], (N, O) means containing N and O, MA contains one or more elements selected from Sr, Ca, Ba, Na, K, Y, Gd and La, MB contains one or more elements selected from Li, Mg and Zn, MC contains one or more elements selected from Al, Si, Ga, In and Sc, X contains one or more elements selected from F, Cl, Br and I, Re contains one or more elements selected from Eu, Ce, Pr, Tb and Dy, and a, b, c, d, e, and x respectively satisfy the following formula: 0.7≤a≤1.3 0.7≤b≤1.3 2.4≤c≤3.6 3.2≤d≤4.8 0.0≤e≤0.2 0.0＜x≤0.2。 12. The light emitting device according to claim 1 or 2, wherein: The red phosphor at least includes: a phosphor including a crystal phase having a composition represented by the following formula [4], Re x MA a MB b (MC' 1－y MD y ) c (N, O) d X e [4] In the formula [4], (N, O) means containing N and O, MA contains one or more elements selected from Sr, Ca, Ba, Na, K, Y, Gd and La, MB contains one or more elements selected from Li, Mg and Zn, MC' is Al, MD contains one or more elements selected from Si, Ga, In and Sc, X contains one or more elements selected from F, Cl, Br and I, Re contains one or more elements selected from Eu, Ce, Pr, Tb and Dy, and a, b, c, d, e, x, y respectively satisfy the following formula: 0.7≤a≤1.3 0.7≤b≤1.3 2.4≤c≤3.6 3.2≤d≤4.8 0.0≤e≤0.2 0.0＜x≤0.2 0.0＜y≤1.0。 13. The light emitting device according to claim 1 or 2, wherein: The second light-emitting body further includes a yellow phosphor and / or a green phosphor.

14. The light emitting device according to claim 13, wherein: The yellow phosphor and / or the green phosphor includes any one or more of a garnet-based phosphor, a silicate-based phosphor, a nitride phosphor, and a nitride oxide phosphor.

15. A lighting device comprising the light emitting device according to claim 1 or 2 as a light source.

16. An image display device comprising the light emitting device according to claim 1 or 2 as a light source.

17. A vehicle indicator lamp comprising the light emitting device according to claim 1 or 2 as a light source.

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