Light-emitting devices, illumination devices, image display devices, and vehicle indicator lights

Abstract

To provide a light emitting device, a lighting device, an image display device and an indicator lamp for vehicles, characterized by excellent color rendering properties.SOLUTION: The present invention provides a light emitting device which comprises a phosphor comprising a crystal phase of a composition represented by formula (1): Rex(Sr1-yMAy)aMBbMCcNdOeXf (MA represents one or more elements that are selected from the group consisting of Ca, Ba, Na, K, Y, Gd and La; MB represents one or more elements that are selected from the group consisting of Li, Mg and Zn; MC represents one or more elements that are selected from the group consisting of Al, Si, Ga, In and Sc; X represents one or more elements that are selected from the group consisting of F, Cl, Br and I; Re represents one or more elements that are selected from the group consisting of Eu, Ce, Pr, Tb and Dy; and a, b, c, d, e, f, x and y respectively satisfy 0.8≤a≤1.2, 1.4≤b≤2.6, 1.4≤c≤2.6, 1.1≤d≤2.9, 1.1≤e≤2.9, 0.0≤f≤0.1, 0.0<x≤0.2, and 0.0<y≤0.7).SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] In recent years, due to the trend of energy conservation, the demand for lighting and backlights using LEDs has been increasing. The LEDs used here are white light-emitting LEDs in which a phosphor is disposed on an LED chip that emits light having a blue or near-ultraviolet wavelength.

[0003] As such a type of white light-emitting LED, in recent years, those using a nitride phosphor that emits red light and a phosphor that emits green light as excitation light from a blue LED chip on a blue LED chip have been used. As for the LED, further luminous efficiency is required, and a light-emitting device including a phosphor having excellent light-emitting characteristics as a red phosphor is desired.

[0004] Examples of the red phosphor used in the light-emitting device include, for example, the general formula K2(Si,Ti)F6:Mn, K2Si 1-x Na x Al x KSF phosphor represented by F6:Mn (0 < x < 1), S / CASN phosphor represented by the general formula (Sr,Ca)AlSiN3:Eu, etc. are known. However, since the KSF phosphor is a highly toxic substance activated by Mn, a phosphor that is more friendly to the human body and the environment is required. In addition, for the S / CASN phosphor, many have a relatively large half-value width (FWHM) of about 80 nm to 90 nm, and a new red phosphor having a smaller half-value width is required.

[0005] In addition, as a red phosphor applicable to recent light-emitting devices, for example, Patent Document 1 describes a phosphor represented by the composition formula SrLiAl^N^:Eu in an example, and a light-emitting device using the same.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Patent No. 6335884 [Summary of the Invention] [Problems to be Solved by the Invention]

[0007] However, since the phosphor described in Patent Document 1 has a long emission peak wavelength of about 650 nm, it has a problem that the red sensitivity is low, the lumen equivalent (Lm / W) in the light-emitting device decreases, and the color rendering property or color reproducibility tends to decrease when used for lighting or display.

[0008] 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 a vehicle display lamp having good color rendering property or color reproducibility. [Means for Solving the Problems]

[0009] As a result of intensive studies, the present inventors have found that the above problems can be solved by using a light-emitting device including a phosphor containing a crystal phase represented by a specific composition, and have completed the present invention. That is, the present invention includes the following.

[0010] 〔1〕 A light-emitting device including a phosphor containing a crystal phase having a composition represented by the following formula [1]. Re x (Sr 1-y MA y ) a MB b MC c N d O e X f [1] (In the above formula [1], MA contains one or more elements selected from the group consisting of Ca, Ba, Na, K, Y, Gd, and La, MB contains one or more elements selected from the group consisting of Li, Mg, and Zn, MC contains one or more elements selected from the group consisting of Al, Si, Ga, In, and Sc, X contains one or more elements selected from the group consisting of F, Cl, Br, and I, Re contains one or more elements selected from the group consisting of Eu, Ce, Pr, Tb, and Dy, a, b, c, d, e, f, x, and y each satisfy the following formulas. 0.8 ≤ a ≤ 1.2 1.4 ≤ b ≤ 2.6 1.4 ≤ c ≤ 2.6 1.1 ≤ d ≤ 2.9 1.1 ≤ e ≤ 2.9 0.0 ≤ f ≤ 0.1 0.0 < x ≤ 0.2 0.0 < y ≤ 0.7)

[0011] [2] In the powder X-ray diffraction spectrum of the phosphor, when the peak intensity of (110) appearing in the region of 2θ = 10 to 12 degrees is Ix and the peak intensity of (121) appearing in the region of 2θ = 37 to 39 degrees is Iy, 0 < Ix / Iy < 0.2, and when the peak intensity of (111) derived from the SrO phase of the impurity phase appearing in the region of 2θ = 30 degrees is Iz, Iz / Iy < 0.25. The light-emitting device according to [1].

[0012] [3] In the formula [1], 0.0 ≤ y ≤ 0.05. The light-emitting device according to [1] or [2].

[0013] [4] In the formula [1], MA is Ca. The light-emitting device according to any one of [1] to [3].

[0014] [5] In the formula [1], 80 mol% or more of MB is Li. The light-emitting device according to any one of [1] to [4].

[0015] [6] In the formula [1], 80 mol% or more of MC is Al. The light-emitting device according to any one of [1] to [5].

[0016] [7] In the formula [1], 80 mol% or more of Re is Eu. The light-emitting device according to any one of [1] to [6].

[0017] [8] The light-emitting apparatus according to any one of [1] to [7], wherein the phosphor has an emission peak wavelength in the range of 620 nm or more and 645 nm or less in its emission spectrum.

[0018] [9] The light-emitting apparatus according to any one of [1] to [8], wherein the phosphor has a full width at half maximum (FWHM) of 70 nm or less in its emission spectrum.

[0019]

[10] The light-emitting device according to any one of [1] to [9], further comprising a yellow phosphor and / or a green phosphor.

[0020]

[11] The light-emitting apparatus according to

[10] , wherein the yellow phosphor and / or green phosphor comprises one or more of garnet-based phosphors, silicate-based phosphors, nitride phosphors, and oxynitride phosphors.

[0021]

[12] The light-emitting device according to any one of [1] to

[11] , comprising a first light-emitting body and a second light-emitting body that emits visible light upon irradiation with light from the first light-emitting body, wherein the second light-emitting body includes a phosphor containing a crystalline phase having a composition represented by formula [1].

[0022]

[13] A lighting device equipped with the light-emitting device described in

[12] as a light source.

[0023]

[14] An image display device equipped with the light-emitting device described in

[12] as a light source.

[0024]

[15] A vehicle indicator light equipped with the light-emitting device described in

[12] as a light source. [Effects of the Invention]

[0025] According to the present invention, it is possible to provide a light-emitting device with good color rendering, as well as a high-quality lighting device, image display device, and vehicle indicator light. [Brief explanation of the drawing]

[0026] [Figure 1]XRD spectrum chart of Sample 2 in the examples. [Figure 2] Emission spectrum chart of Sample 2 in the examples. [Figure 3] Chart showing the emission characteristics of the simulated light-emitting device in the examples.

Mode for Carrying Out the Invention

[0027] Hereinafter, embodiments and exemplifications of the present invention will be shown and described. However, the present invention is not limited to the following embodiments and exemplifications, etc., and can be arbitrarily modified and implemented without departing from the gist of the present invention.

[0028] In this specification, a numerical range represented by "~" means a range including the numerical values described before and after "~" as the lower limit value and the upper limit value. In the phosphor composition formula in this specification, the delimiter of each composition formula is represented by a comma (,). Also, when listing a plurality of elements separated by a comma (,), it indicates that one or more of the listed elements may be contained in any combination and composition. For example, the composition formula "(Ca,Sr,Ba)Al2O4:Eu" includes "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", "Ca 1-x-y Sr x Ba y Al2O4:Eu" (where 0 < x < 1, 0 < y < 1, and 0 < x + y < 1 in the formula). It is assumed that all are comprehensively shown.

[0029] <Phosphor> In one embodiment, the present invention is a light-emitting device, which comprises a phosphor (hereinafter sometimes referred to as "the phosphor of this embodiment") containing a crystalline phase having a composition represented by the following formula [1]. Re x (Sr 1-y MA y ) a MB b MC c N d O e X f [1] (In the above formula [1], MA contains one or more elements selected from the group consisting of Ca, Ba, Na, K, Y, Gd, and La. MB contains one or more elements selected from the group consisting of Li, Mg, and Zn. MC contains one or more elements selected from the group consisting of Al, Si, Ga, In, and Sc. X contains one or more elements selected from the group consisting of F, Cl, Br, and I. Re contains one or more elements selected from the group consisting of Eu, Ce, Pr, Tb, and Dy. a, b, c, d, e, f, x, and y each satisfy the following equation. 0.8 ≤ a ≤ 1.2 1.4 ≤ b ≤ 2.6 1.4 ≤ c ≤ 2.6 1.1 ≤ d ≤ 2.9 1.1 ≤ e ≤ 2.9 0.0 ≤ f ≤ 0.1 0.0 <x≦0.2 0.0 <y≦0.7)

[0030] 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), but in the present invention, from the viewpoint of wave height wavelength and emission quantum efficiency, Re contains one or more elements selected from the group consisting of Eu, Ce, Pr, Tb, and Dy, preferably containing Eu, more preferably 80 mol% or more of Re is Eu, and even more preferably Re is Eu.

[0031] In formula [1], Sr represents strontium.

[0032] In formula [1], MA comprises one or more elements selected from the group consisting of calcium (Ca), barium (Ba), sodium (Na), potassium (K), yttrium (Y), gadolinium (Gd), and lanthanum (La), preferably comprising Ca, and more preferably MA is Ca.

[0033] In formula [1], MB comprises one or more elements selected from the group consisting of lithium (Li), magnesium (Mg), and zinc (Zn), preferably containing Li, more preferably 80 mol% or more of MB being Li, and even more preferably MB being Li.

[0034] In formula [1], MC comprises one or more elements selected from the group consisting of aluminum (Al), silicon (Si), gallium (Ga), indium (In), and scandium (Sc), preferably comprising Al or Si, more preferably Al, even more preferably 80 mol% or more of MC being Al, and particularly preferably MC being Al.

[0035] In formula [1], N represents nitrogen and O represents oxygen.

[0036] In formula [1], X includes one or more elements selected from the group consisting of fluorine (F), chlorine (Cl), bromine (Br), and iodine (I). That is, in certain embodiments, from the viewpoint of stabilizing the crystal structure and balancing the charge of the entire phosphor, N and O may be partially substituted with the halogen elements represented by X.

[0037] The above formula [1] includes cases where components other than those specified are inevitably, unintentionally, or derived from trace amounts of added components, etc. Other components not explicitly mentioned include elements with atomic numbers one level different from those intentionally added, elements in the same group as those intentionally added, rare earth elements other than those intentionally added, halogen elements when halides are used as the Re raw material, and other elements that may commonly be present as impurities in various raw materials. Other components that are not explicitly stated may be present inevitably or unintentionally, for example, from impurities in the raw materials, or introduced during manufacturing processes such as grinding or synthesis. Trace amounts of added components include reaction aids and Re raw materials.

[0038] In the above formula [1], a, b, c, d, e, f, and x represent the molar content of MA, MB, MC, N, O, X, and Re contained in the phosphor, respectively. Also, y represents the molar content of MA when the total molar amount of Sr and MA is set to 1.

[0039] The value of a is usually 0.7 or higher, preferably 0.8 or higher, more preferably 0.85 or higher, and even more preferably 0.9 or higher, and is usually 1.3 or lower, preferably 1.2 or lower, and more preferably 1.1 or lower. The values ​​of b and c are, independently, usually 1.4 or higher, preferably 1.6 or higher, more preferably 1.8 or higher, and usually 2.6 or lower, preferably 2.4 or lower, more preferably 2.2 or lower. The values ​​of d and e are, independently, usually 1.1 or higher, preferably 1.4 or higher, more preferably 1.7 or higher, and usually 2.9 or lower, preferably 2.6 or lower, more preferably 2.3 or lower. The value of f is usually 0.0 or greater, usually 0.1 or less, preferably 0.06 or less, more preferably 0.04 or less, and even more preferably 0.02 or less. The value of x is greater than 0.0, usually 0.0001 or greater, preferably 0.001 or greater, usually 0.2 or less, preferably 0.15 or less, more preferably 0.1 or less, and even more preferably 0.08 or less.

[0040] The crystal structure is stabilized when b, c, d, and e are within the above ranges. Furthermore, the values ​​of d, e, and f can be appropriately adjusted to balance the overall charge of the phosphor.

[0041] The value of y is greater than 0.0, usually 0.01 or greater, preferably 0.05 or greater, more preferably 0.1 or greater, even more preferably 0.2 or greater, usually 0.7 or less, preferably 0.6 or less, more preferably 0.5 or less, and even more preferably 0.4 or less. When the value of y falls within the above range, the crystal structure is stabilized, and the phosphor exhibits a good emission peak wavelength.

[0042] Furthermore, when the value of a falls within the above range, the crystal structure is stabilized, and a phosphor with fewer heterogeneous phases is obtained.

[0043] The values ​​of b+c and d+e+f are, independently, preferably 3.0 or greater, more preferably 3.4 or greater, even more preferably 3.7 or greater, preferably 5.0 or less, more preferably 4.6 or less, and even more preferably 4.3 or less. The crystal structure is stabilized when the values ​​of b+c and d+e+f are within the above ranges. When the content of each component is within the above-mentioned range, it is preferable in that the resulting phosphor exhibits a good emission peak wavelength and full width at half maximum in its emission spectrum.

[0044] The method for determining the elemental composition of the phosphor is not particularly limited and can be determined by conventional methods, such as GD-MS, ICP spectroscopy, or energy-dispersive X-ray analysis (EDX).

[0045] [Grain size of the crystalline phase] The particle size of the crystalline phase of the phosphor is typically 2 μm to 35 μm in volume-based average particle size, with a lower limit of preferably 3 μm, more preferably 4 μm, and even more preferably 5 μm, and an upper limit of preferably 30 μm or less, more preferably 25 μm or less, even more preferably 20 μm, and particularly preferably 15 μm. A volume-based average particle size of 30 μm or more is preferable from the viewpoint of the luminescence characteristics exhibited by the crystalline phase within the LED package, and a volume-based average particle size of 30 μm or less is preferable from the viewpoint of the luminescence characteristics exhibited by the crystalline phase within the LED package, and a volume-based average particle size of 30 μm or more is preferable from the viewpoint of the crystalline phase being able to avoid noise clogging during the manufacturing process of the LED package. The volume-based average particle size of the crystalline phase of a phosphor can be measured using a laser particle size analyzer. Here, the volume-based average particle size is the particle size (d) at which the relative particle amount on a volume basis becomes 50% when the particle size distribution (cumulative distribution) is determined by measuring the sample using a particle size distribution analyzer that uses the laser diffraction / scattering method as its measurement principle. 50 ) is defined as follows.

[0046] {Physical properties of phosphors, etc.} [Space group] The crystalline system (space group) of the phosphor is more preferably P42 / m. The space group of the phosphor is not particularly limited as long as the statistically considered average structure within the range distinguishable by powder X-ray diffraction or single-crystal X-ray diffraction shows a repeating period of the above length, but it is preferably belonging to number 84 based on "International Tables for Crystallography (Third, revised edition), Volume A SPACE-GROUP SYMMETRY". As a result of the aforementioned space group, the full width at half maximum (FWHM) in the emission spectrum is reduced, and a phosphor with high emission efficiency can be obtained. Here, the space group can be determined according to conventional methods, for example, by electron diffraction, X-ray diffraction structural analysis using powder or single crystal, and neutron diffraction structural analysis.

[0047] In the powder X-ray diffraction spectrum of the phosphor, when the peak intensity of (110) appearing in the region 2θ = 10 to 12 degrees is denoted as Ix, the peak intensity of (121) appearing in the region 2θ = 37 to 39 degrees is denoted as Iy, and the peak intensity of (111) originating from the impurity phase SrO phase appearing in the region 2θ = 30 degrees is denoted as Iz, the relative intensity of Ix when Iy is set to 1, Ix / Iy, is usually 0.3 or less, preferably 0.25 or less, more preferably 0.2 or less, and even more preferably 0.15 or less, and is usually 0 or greater, but the smaller the value, the better. Furthermore, Iz / Iy, which is the relative intensity of Iz when Iy is set to 1, is usually 0.5 or less, preferably 0.4 or less, more preferably 0.3 or less, even more preferably 0.25 or less, particularly preferably 0.2 or less, and especially preferably 0.15 or less, and is usually 0 or greater, but the smaller the better.

[0048] The peak (121) above is one of the characteristic peaks observed when the crystal system (space group) is P42 / m, and a relatively high Iy value allows for the acquisition of a phosphor with higher P42 / m phase purity. When Ix / Iy or Iz / Iy is below the above upper limit, the phosphor has high phase purity and a small full width at half maximum (FWHM), thus improving the luminescence efficiency of the light-emitting device.

[0049] [Characteristics of the emission spectrum] The phosphor is excited by irradiation with light of an appropriate wavelength and emits red light exhibiting a good emission peak wavelength and full width at half maximum (FWHM) in its emission spectrum. The emission spectrum and the excitation wavelength, emission peak wavelength, and FWHM related to its measurement are described below.

[0050] (Excitation wavelength) The phosphor typically has an excitation peak in a wavelength range of 270 nm or higher, preferably 300 nm or higher, more preferably 320 nm or higher, even more preferably 350 nm or higher, and particularly preferably 400 nm or higher, and typically 500 nm or lower, preferably 480 nm or lower, and more preferably 460 nm or lower. That is, it is excited by light in the near-ultraviolet to blue region. The shape of the emission spectrum and the descriptions of the emission peak wavelength and full width at half maximum below are applicable regardless of the excitation wavelength. However, from the viewpoint of improving quantum efficiency, it is preferable to irradiate with light having wavelengths within the above range, which provides good absorption and excitation efficiency.

[0051] (Emission peak wavelength) The phosphor has a peak wavelength in its emission spectrum that is typically 620 nm or higher, preferably 625 nm or higher, and more preferably 630 nm or higher. Furthermore, the peak wavelength in this emission spectrum is typically 649 nm or lower, preferably 645 nm or lower, and more preferably 640 nm or lower.

[0052] If the peak wavelength in the emission spectrum of the phosphor is within the above range, the emitted color will be a good red, and by using this, a light-emitting device with good color rendering or color reproduction can be provided. Furthermore, if the peak wavelength in the emission spectrum of the phosphor is below the above upper limit, a light-emitting device with good red luminescence sensitivity and a good lumen equivalent of lm / W can be provided.

[0053] (FMA of the emission spectrum) The phosphor has a full width at half maximum of the emission peak in its emission spectrum that is typically 80 nm or less, preferably 70 nm or less, more preferably 60 nm or less, even more preferably 55 nm or less, and particularly preferably 50 nm or less, and is typically 10 nm or more. Because the full width at half maximum of the emission peak is within the above range, when used in image display devices such as liquid crystal displays, the color reproduction range of the image display device can be widened without reducing color purity. Furthermore, by having the emission peak wavelength and full width at half maximum below the above upper limits, it is possible to provide a phosphor with relatively high luminous sensitivity in the emission wavelength region, and by using such a phosphor in a light-emitting device, it is possible to provide a light-emitting device with high conversion efficiency.

[0054] To excite the phosphor with light of a wavelength of 450 nm, for example, a GaN-based LED can be used. Furthermore, the emission spectrum of the phosphor, as well as its emission peak wavelength, peak relative intensity, and peak full width at half maximum, can be measured using commercially available spectral measuring devices, such as a trend analyzer equipped with a light source having an emission wavelength of 300-400 nm, such as a commercially available xenon lamp, and a general-purpose photodetector.

[0055] <Light-emitting device> In one embodiment, the present invention is a light-emitting device comprising a first light-emitting element (excitation light source) and a second light-emitting element that emits visible light upon irradiation with light from the first light-emitting element, wherein the second light-emitting element comprises the phosphor of this embodiment, which includes a crystalline phase having a composition represented by formula [1]. Here, the second light-emitting element may be used alone, or two or more may be used in any combination and ratio.

[0056] The light-emitting device in this embodiment includes, as the second light-emitting element, the phosphor of this embodiment which includes a crystalline phase having the composition represented by formula [1], and further, a phosphor that emits fluorescence in the yellow, green, or red region (orange to red) when irradiated with light from an excitation light source can be used. Specifically, when configuring the light-emitting device, the yellow phosphor is preferably one that has an emission peak in the wavelength range of 550 nm or more and 600 nm or less, and the green phosphor is preferably one that has an emission peak in the wavelength range of 500 nm or more and 560 nm or less. The orange or red phosphor usually has an emission peak in the wavelength range of 615 nm or more, preferably 620 nm or more, more preferably 625 nm or more, even more preferably 630 nm or more, and usually 660 nm or less, preferably 650 nm or less, more preferably 645 nm or less, and even more preferably 640 nm or less. By appropriately combining phosphors in the above wavelength ranges, a light-emitting device exhibiting excellent color reproduction can be provided. Furthermore, an excitation source having an emission peak in the wavelength range of less than 420 nm may also be used.

[0057] The following describes the configuration of the light-emitting device when the phosphor of this embodiment is used, which includes a crystalline phase having a composition represented by formula [1] and having an emission peak in the wavelength range of 620 nm to 645 nm, and the first light-emitting element has an emission peak in the wavelength range of 300 nm to 460 nm; however, this embodiment is not limited to these.

[0058] In the above case, the light-emitting device of this embodiment can be, for example, in one of the following forms (A), (B), or (C). (A) An embodiment in which a phosphor of this embodiment is used, in which a first light-emitting element has an emission peak in the wavelength range of 300 nm to 460 nm, and a second light-emitting element includes at least one phosphor (yellow phosphor) having an emission peak in the wavelength range of 550 nm to 600 nm, and a crystalline phase having the composition described in [1] above. (B) An embodiment in which a phosphor of this embodiment is used, in which a first light-emitting element is used that has an emission peak in the wavelength range of 300 nm to 460 nm, and in which a second light-emitting element is used that includes at least one phosphor (green phosphor) having an emission peak in the wavelength range of 500 nm to 560 nm, and a crystalline phase having the composition described in [1] above. (C) An embodiment in which a phosphor of this embodiment is used, in which a first light-emitting material having an emission peak in the wavelength range of 300 nm to 460 nm is used, and a second light-emitting material having a crystalline phase having the composition described in [1] above, comprising at least one phosphor (yellow phosphor) having an emission peak in the wavelength range of 550 nm to 600 nm, at least one phosphor (green phosphor) having an emission peak in the wavelength range of 500 nm to 560 nm, and the first light-emitting material having an emission peak in the wavelength range of 300 nm to 460 nm as the first light-emitting material.

[0059] In the above embodiment, commercially available green or yellow phosphors can be used, such as garnet-based phosphors, silicate-based phosphors, nitride phosphors, and oxynitride phosphors.

[0060] (Yellow phosphor) Examples of garnet-based phosphors that can be used as yellow phosphors include (Y,Gd,Lu,Tb,La)3(Al,Ga)5O 12 :(Ce,Eu,Nd), silicate phosphors include, for example, (Ba,Sr,Ca,Mg)2SiO4:(Eu,Ce), nitride phosphors and oxynitride phosphors include, for example, (Ba,Ca,Mg)Si2O2N2:Eu(SION-based phosphor), (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 Examples include (Ce, Eu) (LSN phosphors). These may be used individually or in combination of two or more types. As for the yellow phosphor, garnet-based phosphors are preferred among the above phosphors, and among them, Y3Al5O 12 A YAG-based phosphor represented by :Ce is most preferred.

[0061] (Green phosphor) Examples of garnet-based phosphors that can be used as green phosphors include (Y,Gd,Lu,Tb,La)3(Al,Ga)5O 12 :(Ce,Eu,Nd), Ca3(Sc,Mg)2Si3O 12 Examples of silicate phosphors include (Ce,Eu)(CSMS phosphor) and (Ba,Sr,Ca,Mg)3SiO 10 Examples of oxide phosphors include (Eu,Ce), (Ba,Sr,Ca,Mg)2SiO4:(Ce,Eu)(BSS phosphor), (Ca,Sr,Ba,Mg)(Sc,Zn)2O4:(Ce,Eu)(CASO phosphor), (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 12N2: (Eu, Ce) (BSON phosphor), as the aluminate phosphor, for example, (Ba, Sr, Ca, Mg)2Al 10 O 17 : (Eu, Mn) (GBAM phosphor), etc. These may be used alone or in combination of two or more.

[0062] (Red phosphor) As the red phosphor, the phosphor of the present embodiment containing a crystal phase having the composition represented by the above formula [1] is used. In addition to the phosphor of the present embodiment, for example, other orange to red phosphors such as Mn-activated fluoride phosphors, garnet phosphors, sulfide phosphors, nanoparticle phosphors, nitride phosphors, oxynitride phosphors, etc. can be used. As other orange to red phosphors, for example, the following phosphors can be used. As the Mn-activated fluoride phosphor, for example, K2(Si, Ti)F6:Mn, K2Si 1-x Na x Al x F6:Mn (0 < x < 1) (collectively KSF phosphor), as the sulfide phosphor, for example, (Sr, Ca)S:Eu (CAS phosphor), La2O2S:Eu (LOS phosphor), as the garnet phosphor, for example, (Y, Lu, Gd, Tb)3Mg2AlSi2O 12 :Ce, as the nanoparticles, for example, CdSe, as the nitride or oxynitride phosphor, 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)2Si(5)(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 (where M is Ca, Sr, etc.) (α-sialon phosphor), Li(Sr,Ba)Al3N4:Eu (where x in the above is all 0 < x < 1), etc. These may be used alone or in combination of two or more.

[0063] [Configuration of the light-emitting device] The light-emitting device according to this embodiment has a first light-emitting body (excitation light source), and can use the phosphor of this embodiment containing a crystal phase having a composition represented by at least the above formula [1] as the second light-emitting body. Its configuration is not limited, and a known device configuration can be arbitrarily adopted. Examples of the device configuration and embodiments of the light-emitting device include those described in JP-A-2007-291352. In addition, examples of the form of the light-emitting device include bullet type, cup type, chip-on-board, remote phosphor, etc.

[0064] [Applications of the light-emitting device] The applications of the light-emitting device are not particularly limited, and it can be used in various fields where ordinary light-emitting devices are used. However, from the viewpoint of high color rendering properties, it can be particularly preferably used as a light source for lighting devices and image display devices. In addition, from the point of having a phosphor with a good red emission wavelength, it can also be used for red vehicle indicator lights or vehicle indicator lights of white light containing the red color.

[0065] [Lighting device] In one embodiment of the present invention, a lighting device including the above light-emitting device as a light source can be provided. When applying the above light-emitting device to a lighting device, there is no limitation on the specific configuration of the lighting device, and the above-described light-emitting device can be appropriately incorporated into a known lighting device and used. For example, a surface-emitting lighting device in which a large number of light-emitting devices are arranged on the bottom surface of a holding case can be mentioned.

[0066] [Image display device] In one embodiment of the present invention, an image display device including the above light-emitting device as a light source can be provided. When the aforementioned light-emitting device is used as a light source for an image display device, there are no restrictions on the specific configuration of the image display device, but it is preferable to use it together with a color filter. For example, when the image display device is a color image display device using a color liquid crystal display element, the light-emitting device can be used as a backlight, and the image display device can be formed by combining a light shutter using liquid crystal and a color filter having red, green, and blue pixels.

[0067] [Vehicle indicator lights] In one embodiment, the present invention can be a vehicle indicator light equipped with the aforementioned light-emitting device. In certain embodiments, the light-emitting device used in vehicle indicator lights is preferably a light-emitting device that emits white light. The light-emitting device that emits white light preferably has a deviation of the light color from the blackbody radiation trajectory (duv) of -0.0200 to 0.0200, and a color temperature of 5000K or higher and 30000K or lower. In certain embodiments, the light-emitting device used for vehicle indicator lights is preferably a light-emitting device that emits red light. In such embodiments, for example, the light-emitting device may absorb blue light emitted from a blue LED chip and emit red light, thereby providing a vehicle indicator light that emits red light. Vehicle indicator lights include headlights, side lights, reverse lights, turn signals, brake lights, fog lights, and other lights installed on a vehicle for the purpose of indicating something to other vehicles or people. [Examples]

[0068] The present invention will be further described below with reference to experimental examples that replace the embodiments described herein, but the present invention is not limited to the following without departing from its essence.

[0069] {Measurement method} [Powder X-ray diffraction measurement] Powder X-ray diffraction (XRD) was precisely measured using a SmartLab 3 powder X-ray diffractometer (manufactured by Rigaku). The measurement conditions are as follows: Using CuKα tube X-ray output = 40kV, 200mA Divergent slit = automatic Detector = High-speed 1D X-ray detector (D / teX Ultra 250) Investigation range 2θ = 5 to 80 degrees Reading width = 0.02 degrees

[0070] [Measurement of emission spectrum] Using a xenon lamp, light with a wavelength of 365 nm was irradiated onto a phosphor, and the emission spectrum in the wavelength range of 450 to 800 nm was measured using a spectrofluorometer.

[0071] As an example of the present invention, red phosphors (Samples 1-5) corresponding to the phosphor of this embodiment, which include a crystalline phase having the composition represented by formula [1], were prepared. In addition, for comparison with the present invention, Sample 6 was prepared, which does not satisfy formula [1] because its Ca content is 0. Table 1 shows the composition, space group, emission peak wavelength, and full width at half maximum for each sample, along with the literature values ​​for SrLiAl3N4 as a reference example. Figures 1 and 2 show the XRD and emission spectral charts of the phosphor in Sample 2 as representative examples. Sample 2 has a good full width at half maximum of 65 nm, and the phase purity is also good, with Ix / Iy and Iz / Iy values ​​of 0.194 and 0.216 respectively in XRD. This indicates that when applied to a light-emitting device, it can be used to obtain a light-emitting device with good conversion efficiency.

[0072] [Table 1]

[0073] The phosphors in samples 1-5 of this experiment all exhibited a space group P42 / m, and their emission peak wavelengths were in the range of 620nm to 640nm, which is ideal for color rendering or color reproduction when used with a white LED.

[0074] Next, the results of a simulation relating to the characteristics of the light-emitting device equipped with the phosphor that satisfies equation [1] are described.

[0075] The emission spectrum of a white LED equipped with the phosphor from Sample 2 or an SCASN phosphor (BR-102C, Mitsubishi Chemical Corporation) with an emission peak wavelength of 628 nm as the red phosphor, and a LuAG phosphor (BG-801 / A4, Mitsubishi Chemical Corporation) as the green phosphor was derived using the method described above. All simulations were performed assuming a blue LED chip emitting light at 449 nm. The amounts of green and red phosphors were adjusted so that the chromaticity coordinates matched the coordinates of white light at 3000K to 8000K on the Planck curve, and the characteristics at each color temperature were compared. The results are shown in Figures 3(a) to (f). The color rendering index Ra, the color rendering index R9 for red, and the conversion efficiency (LER) obtained from each spectrum are shown in Table 2. Note that the “relative value of phosphor mass” in Table 2 refers to the mass ratio of each color phosphor when the total mass of red phosphor + green phosphor is set to 100%.

[0076] [Table 2]

[0077] As shown in Table 2, a light-emitting device equipped with a phosphor containing a crystalline phase having the composition represented by formula [1] exhibits superior conversion efficiency and color rendering over a wide color temperature range compared to a conventional red phosphor.

[0078] Furthermore, the characteristics of an image display device using the aforementioned white LED as a backlight were also evaluated through simulation. Using the phosphor from Sample 2 or an SCASN phosphor with an emission peak wavelength of 628 nm (Mitsubishi Chemical Corporation, BR-102C) as the red phosphor, and a β-SiAlON phosphor (Mitsubishi Chemical Corporation, BG-601 / K) as the green phosphor, the conversion efficiency and the percentage of the NTSC color gamut that the LED device can display (hereinafter sometimes referred to as the coverage rate) were calculated when the chromaticity coordinates (x, y) after passing the light from the white LED through a color filter used in a typical image display device (display, etc.) were adjusted to (0.3101, 0.3162). These results are shown in Table 3.

[0079] [Table 3]

[0080] As shown in Table 3, light-emitting devices and image display devices equipped with a phosphor containing a crystalline phase having the composition represented by formula [1] show superior conversion efficiency and color gamut coverage compared to conventional red phosphors.

[0081] As shown above, a phosphor containing a crystalline phase having the composition represented by formula [1] has a preferred wavelength for red and an excellent full width at half maximum. By using a light-emitting device equipped with such a phosphor, it is possible to provide light-emitting devices, lighting devices, image display devices, and vehicle indicator lights that have excellent color rendering and other characteristics.

Claims

1. A light-emitting device comprising a phosphor having a crystalline phase having a composition represented by the following formula [1], wherein the crystalline system is P42 / m, the full width at half maximum of the emission peak in the emission spectrum is 10 nm or more and 80 nm or less, and the emission peak wavelength in the emission spectrum is 625 nm or more and 645 nm or less. Re ｘ (Sr １－ｙ MA ｙ ) ａ MB ｂ MC ｃ N ｄ O ｅ X ｆ [1] (In the above formula [1], MA contains Ca, MB includes Li, MC contains Al, X contains one or more elements selected from the group consisting of F, Cl, Br, and I. Re includes EU, a, b, c, d, e, f, x, and y each satisfy the following equation. 0.8 ≤ a ≤ 1.2 1.4 ≤ b ≤ 2.6 1.4 ≤ c ≤ 2.6 1.1 ≤ d ≤ 2.9 1.1 ≤ e ≤ 2.9 0.0 ≤ f ≤ 0.1 0.0 < x ≤ 0.2 (0.2 ≤ y ≤ 0.5)

2. The light-emitting device according to claim 1, wherein in the powder X-ray diffraction spectrum of the phosphor, when the peak intensity of (110) appearing in the region 2θ = 10 to 12 degrees is Ix, and the peak intensity of (121) appearing in the region 2θ = 37 to 39 degrees is Iy, 0 < Ix / Iy < 0.2, and when the peak intensity of (111) originating from the SrO phase of the impurity phase appearing in the region 2θ = 30 degrees is Iz, Iz / Iy < 0.

25.

3. The light-emitting device according to claim 1 or 2, wherein in formula [1], MA is Ca.

4. The light-emitting device according to any one of claims 1 to 3, wherein in formula [1], 80 mol% or more of MB is Li.

5. The light-emitting device according to any one of claims 1 to 4, wherein in formula [1], 80 mol% or more of MC is Al.

6. The light-emitting device according to any one of claims 1 to 5, wherein in formula [1], 80 mol% or more of Re is Eu.

7. The light-emitting device according to any one of claims 1 to 6, wherein the phosphor has a full width at half maximum (FWHM) of 70 nm or less in its emission spectrum.

8. The light-emitting device according to any one of claims 1 to 7, further comprising a yellow phosphor and / or a green phosphor.

9. The light-emitting device according to claim 8, wherein the yellow phosphor and / or green phosphor comprises one or more of garnet-based phosphors, silicate-based phosphors, nitride phosphors, and oxynitride phosphors.

10. A light-emitting device according to any one of claims 1 to 9, comprising a first light-emitting element and a second light-emitting element that emits visible light upon irradiation with light from the first light-emitting element, wherein the second light-emitting element includes at least the phosphor.

11. A lighting device comprising the light-emitting device described in claim 10 as a light source.

12. An image display device comprising the light-emitting device described in claim 10 as a light source.

13. A vehicle indicator light comprising the light-emitting device described in claim 10 as a light source.

Images