JP2023057392A - Light-emitting device, lighting device, image display device, and vehicle indicator light - Google Patents

Abstract

A light-emitting device, a lighting device, a screen display device, and a vehicle indicator lamp having good color rendering properties are provided.
A light-emitting device includes 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]
(MA is one or more elements selected from Ca, Ba, Na, K, Y, Gd, and La; MB is one or more elements selected from Li, Mg, and Zn; MC is Al, Si, Ga , In, and Sc, X is one or more elements selected from F, Cl, Br, and I. Re is one element selected from Eu, Ce, Pr, Tb, and Dy. The above elements a, b, c, d, e, f, x and y respectively satisfy the following formulae.
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)
[Selection drawing] Fig. 1

Description

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

In recent years, the demand for illumination and backlights using LEDs has increased in response to the trend toward energy conservation. The LEDs used here are white-emitting LEDs in which a phosphor is placed on an LED chip that emits light in blue or near-ultraviolet wavelengths.

As such a type of white-light-emitting LED, there has recently been one in which a red-light-emitting nitride phosphor and a green-light-emitting phosphor are used on a blue LED chip by using blue light from the blue LED chip as excitation light. used. LEDs are required to have higher luminous efficiency, and there is a demand for a light-emitting device including a red phosphor having excellent luminous properties.

Red phosphors used in light-emitting devices are represented, for example, by the general formulas K ₂ (Si, Ti) F ₆ :Mn and K ₂ Si _1-x Na _x Al _x F ₆ :Mn (0<x<1). KSF phosphor, S/CASN phosphor represented by the general formula (Sr, Ca)AlSiN ₃ :Eu, etc. are known. There is a demand for environmentally friendly phosphors. In addition, many of the S/CASN phosphors have a relatively large full width at half maximum (FWHM) of about 80 nm to 90 nm, and new red phosphors with a smaller full width at half maximum are in demand.

In addition, as a red phosphor that can be applied to recent light emitting devices, for example, Patent Document 1 discloses a phosphor represented by a composition formula of SrLiAl ₃ N ₄ :Eu and a light emitting device using the same as an example. Are listed.

Japanese Patent No. 6335884

However, since the phosphor described in Patent Document 1 has a long emission peak wavelength of about 650 nm, the luminosity of red is low, and the lumen equivalent (Lm/W) in the light emitting device is lowered. However, there is a problem that color rendering or color reproducibility is likely to deteriorate.

SUMMARY OF THE INVENTION 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 vehicular indicator lamp with good color rendering properties or color reproducibility.

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 completed the present invention.
That is, the present invention includes the following.

[1] A light-emitting device comprising 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 formula.
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)

[2] In the powder X-ray diffraction spectrum of the phosphor, 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. 0.25, the light emitting device according to [1].

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

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

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

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

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

[8] The light-emitting device 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 the emission spectrum.

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

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

[11] The description in [10], wherein the yellow phosphor and/or the green phosphor include any one or more of a garnet-based phosphor, a silicate-based phosphor, a nitride phosphor, and an oxynitride phosphor. luminous device.

[12] 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 is represented by the above formula [1] The light-emitting device according to any one of [1] to [11], comprising a phosphor containing a crystal phase having a composition of

[13] A lighting device comprising the light emitting device according to [12] as a light source.

[14] An image display device comprising the light emitting device according to [12] as a light source.

[15] A vehicle indicator light comprising the light emitting device according to [12] as a light source.

ADVANTAGE OF THE INVENTION According to this invention, the light-emitting device with a favorable color rendering property, and a high-quality illuminating device, image display device, and indicator light for vehicles can be provided.

4 is an XRD spectrum chart of Sample 2 in Example. 4 is an emission spectrum chart of Sample 2 in Example. 4 is a chart showing light emission characteristics of a light emitting device simulated in Examples.

Hereinafter, the present invention will be described with reference to embodiments and examples, but the present invention is not limited to the following embodiments and examples, and can be arbitrarily modified without departing from the scope of the present invention. can be implemented.

In this specification, the numerical range represented by "-" means a range including the numerical values before and after "-" as lower and upper limits. In addition, in the compositional formulas of the phosphors in this specification, each compositional formula is delimited by a comma (,). In addition, when a plurality of elements are listed separated by commas (,), 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) Al ₂ O ₄ :Eu” is composed of “CaAl ₂ O ₄ :Eu”, “SrAl ₂ O ₄ :Eu” and “BaAl ₂ O ₄ :Eu”. and "Ca _1-x Sr _x Al ₂ O ₄ :Eu", "Sr _1-x Ba _x Al ₂ O ₄ : Eu", and "Ca _1-x Ba _x Al ₂ O ₄ : Eu", "Ca _1-xy Sr _{x Bay} Al ₂ O ₄ :Eu" (where 0<x<1, 0<y<1, 0<x+y<1) and all inclusive shall be as shown in

<Phosphor>
In one embodiment of the present invention, there is provided a light-emitting device, wherein the light-emitting device is a phosphor containing a crystalline phase having a composition represented by the following formula [1] (hereinafter sometimes referred to as the "phosphor of the present embodiment": There is.)
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 formula.
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)

In formula [1], Re includes europium (Eu), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm) and ytterbium (Yb) can be used. It contains one or more elements selected from the group, preferably contains Eu, more preferably 80 mol % or more of Re is Eu, and still more preferably Re is Eu.

In formula [1], Sr represents strontium.

In formula [1], MA is selected from the group consisting of calcium (Ca), barium (Ba), sodium (Na), potassium (K), yttrium (Y), gadolinium (Gd), and lanthanum (La). It contains more than one element, preferably Ca, more preferably MA is Ca.

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

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

In formula [1], N represents a nitrogen element, and O represents an oxygen element.

In formula [1], X contains 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 maintaining the charge balance of the phosphor as a whole, part of N and O may be substituted with the above halogen element represented by X.

The above formula [1] includes the case where components other than those specified are contained in a trace amount unavoidably, unintentionally, or due to trace addition components or the like.
Ingredients other than those specified include an element whose element number is one different from that of the intentionally added element, a homologous element of the intentionally added element, an intentionally added rare earth element and another rare earth element, and a halogen in the Re raw material. Examples include halogen elements when using a compound, and other elements that can be generally contained as impurities in various raw materials.
Examples of the unavoidable or unintentional inclusion of components other than those specified include, for example, those derived from impurities in raw materials, and those introduced in manufacturing processes such as pulverization and synthesis steps. In addition, a reaction aid, a Re raw material, and the like can be cited as the trace addition component.

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

The value of a is usually 0.7 or more, preferably 0.8 or more, more preferably 0.85 or more, still more preferably 0.9 or more, and usually 1.3 or less, preferably 1.2 or less, more preferably is less than or equal to 1.1.
The values of b and c are each independently usually 1.4 or more, preferably 1.6 or more, more preferably 1.8 or more, and usually 2.6 or less, preferably 2.4 or less, more preferably 2 .2 or less.
The values of d and e are each independently usually 1.1 or more, preferably 1.4 or more, more preferably 1.7 or more, and usually 2.9 or less, preferably 2.6 or less, more preferably 2 .3 or less.
The value of f is usually 0.0 or more and usually 0.1 or less, preferably 0.06 or less, more preferably 0.04 or less, and still more preferably 0.02 or less.
The value of x is greater than 0.0, usually 0.0001 or more, preferably 0.001 or more, and usually 0.2 or less, preferably 0.15 or less, more preferably 0.1 or less, still more preferably 0 0.08 or less.

The crystal structure is stabilized when b, c, d, and e are within the above ranges. Also, the values of d, e, and f can be adjusted appropriately for the purpose of balancing the charge across the phosphor.

The value of y is greater than 0.0, usually 0.01 or more, preferably 0.05 or more, more preferably 0.1 or more, still more preferably 0.2 or more, usually 0.7 or less, preferably 0 0.6 or less, more preferably 0.5 or less, and still more preferably 0.4 or less.
When the value of y is within the above range, the phosphor has a stable crystal structure and a favorable emission peak wavelength.

Further, when the value of a is within the above range, the crystal structure is stabilized, and a phosphor with less heterogeneous phases can be obtained.

The value of b + c and the value of d + e + f are each independently preferably 3.0 or more, more preferably 3.4 or more, still more preferably 3.7 or more, preferably 5.0 or less, more preferably 4 0.6 or less, more preferably 4.3 or less.
The crystal structure is stabilized when the value of b+c and the value of d+e+f are within the above ranges.
It is preferable that the content of any of them is in the range described above, since the peak emission wavelength and the half width of the emission spectrum of the obtained phosphor are good.

The method for specifying the elemental composition of the phosphor is not particularly limited, and can be determined by a conventional method, such as GD-MS, ICP spectroscopic analysis, or energy dispersive X-ray spectrometry (EDX). .

[Particle size of crystal phase The particle size of the crystal phase of the phosphor is usually 2 µm or more and 35 µm or less in terms of volume-based average particle size, and the lower limit is preferably 3 µm, more preferably 4 µm, and even more preferably 5 µm. The upper limit is preferably 30 μm or less, more preferably 25 μm or less, still more preferably 20 μm, and particularly preferably 15 μm. When the volume-based average particle diameter is at least the above lower limit, the crystalline phase is preferable from the viewpoint of light emission characteristics exhibited in the LED package, and when it is at most the above upper limit, the crystalline phase is preferable from the point that noise clogging can be avoided in the manufacturing process of the LED package. .
The volume-based average particle diameter of the crystalline phase of the phosphor can be measured with a laser granulometer. Here, the volume-based average particle size is the volume-based relative particle size when the sample is measured and the particle size distribution (cumulative distribution) is obtained using a particle size distribution measuring device that uses the laser diffraction/scattering method as the measurement principle. Defined as the particle size at which the volume reaches 50% (d ₅₀ ).

{Physical properties of phosphor, etc.}
[Space group]
More preferably, the crystal system (space group) in the phosphor is P42/m. The space group in the phosphor is not particularly limited as long as the average structure considered statistically in the range that can be distinguished by powder X-ray diffraction or single crystal X-ray diffraction shows a repeating period of the above length, Preferably, it belongs to No. 84 based on "International Tables for Crystallography (Third, revised edition), Volume A SPACE-GROUP SYMMETRY".
With the above space group, the full width at half maximum (FWHM) in the emission spectrum becomes small, and a phosphor with good luminous efficiency can be obtained.
Here, the space group can be obtained by a conventional method, for example, by electron beam diffraction, X-ray diffraction structure analysis using powder or single crystal, neutron beam diffraction structure analysis, or the like.

In the powder X-ray diffraction spectrum of the phosphor, the peak intensity of (110) appearing in the region of 2θ = 10 to 12 degrees is Ix, the peak intensity of (121) appearing in the region of 2θ = 37 to 39 degrees is Iy, and 2θ. When the peak intensity of (111) derived from the SrO phase of the impurity phase appearing in the region of = 30 degrees is Iz, Ix/Iy, which is the relative intensity of Ix when Iy is 1, is usually 0.3 or less. It is preferably 0.25 or less, more preferably 0.2 or less, still more preferably 0.15 or less, and is usually 0 or more, but the smaller the better.
In addition, Iz/Iy, which is the relative intensity of Iz when Iy is 1, is usually 0.5 or less, preferably 0.4 or less, more preferably 0.3 or less, and still more preferably 0.25 or less. It is preferably 0.2 or less, particularly preferably 0.15 or less, and is usually 0 or more, but the smaller the better.

The above (121) peak is one of the characteristic peaks observed when the crystal system (space group) is P42/m, and the relatively high Iy results in a higher phase purity of P42/m. high phosphor can be obtained.
When Ix/Iy or Iz/Iy is equal to or less than the above upper limit, the phosphor has a high phase purity and a small full width at half maximum (FWHM), thereby improving the luminous efficiency of the light emitting device.

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

(excitation wavelength)
The phosphor usually has a wavelength of 270 nm or more, preferably 300 nm or more, more preferably 320 nm or more, still more preferably 350 nm or more, particularly preferably 400 nm or more, and usually 500 nm or less, preferably 480 nm or less, more preferably 460 nm or less. It has an excitation peak in the range. That is, they are excited by light in the near-ultraviolet to blue region.
The shape of the emission spectrum and the description of the emission peak wavelength and half width below can be applied regardless of the excitation wavelength, but from the viewpoint of improving the quantum efficiency, light having a wavelength in the above range with good absorption and excitation efficiency is preferably irradiated.

(Emission peak wavelength)
The phosphor generally has a peak wavelength of 620 nm or more, preferably 625 nm or more, more preferably 630 nm or more in the emission spectrum. Also, the peak wavelength in this emission spectrum is usually 649 nm or less, preferably 645 nm or less, more preferably 640 nm or less.

When the peak wavelength in the emission spectrum of the phosphor is within the above range, the luminescent color is good red, and by using this, a light emitting device with good color rendering or color reproducibility can be provided. Further, by setting the peak wavelength in the emission spectrum of the phosphor to the above upper limit or less, it is possible to provide a light-emitting device with good red luminosity and good lumen equivalent lm/W.

(Half width of emission spectrum)
The phosphor has an emission peak half width of usually 80 nm or less, preferably 70 nm or less, more preferably 60 nm or less, even more preferably 55 nm or less, particularly preferably 50 nm or less, and usually 10 nm or more. .
Since the half width of the emission peak is within the above range, the color reproduction range of the image display device can be widened without lowering the color purity when used in an image display device such as a liquid crystal display.
In addition, since the emission peak wavelength and the half-value width are equal to or less than the above upper limits, it is possible to provide a phosphor with relatively high visibility in the emission wavelength region. An expensive light-emitting device can be provided.

A GaN-based LED, for example, can be used to excite the phosphor with light having a wavelength of 450 nm. In addition, the measurement of the emission spectrum of the phosphor and the calculation of its emission peak wavelength, peak relative intensity and peak half-value width are performed using a light source having an emission wavelength of 300 to 400 nm such as a commercially available xenon lamp and general light. It can be done using a commercially available spectrometer, such as a trend meter with a detector.

<Light emitting device>
In one embodiment of the present invention, a light-emitting device including a first light-emitting body (excitation light source) and a second light-emitting body that emits visible light when irradiated with light from the first light-emitting body, The light-emitting device includes, as the second light-emitting body, the phosphor of the present embodiment containing the crystal phase having the composition represented by the above formula [1]. Here, the second luminous body may be used singly, or two or more of them may be used in any combination and ratio.

The light-emitting device of this embodiment contains, as the second light-emitting body, the phosphor of this embodiment containing a crystal phase having a composition represented by the above formula [1], and furthermore, the light from the excitation light source Phosphors that fluoresce in the yellow, green to red region (orange to red) under illumination can be used. Specifically, when constructing a light-emitting device, the yellow phosphor preferably has an emission peak in the wavelength range of 550 nm or more and 600 nm or less, and the green phosphor preferably has an emission peak in the wavelength range of 500 nm or more and 560 nm or less. Those having an emission peak are preferred. In addition, the orange to red phosphor is usually 615 nm or more, preferably 620 nm or more, more preferably 625 nm or more, still more preferably 630 nm or more, and usually 660 nm or less, preferably 650 nm or less, more preferably 645 nm or less, more preferably 640 nm or less. It has emission peaks in the following wavelength ranges.
A light-emitting device exhibiting excellent color reproducibility can be provided by appropriately combining phosphors in the above wavelength band. As for the excitation source, one having an emission peak in a wavelength range of less than 420 nm may be used.

Hereinafter, as the red phosphor, the phosphor of the present embodiment, which has an emission peak in the wavelength range of 620 nm or more and 645 nm or less and contains a crystal phase having a composition represented by the above formula [1], is used, and the first Modes of the light-emitting device using a light-emitting material having an emission peak in the wavelength range of 300 nm or more and 460 nm or less will be described, but the present embodiment is not limited to these.

In the above case, the light-emitting device of this embodiment can have, for example, the following modes (A), (B), or (C).
(A) As the first luminous body, one having an emission peak in the wavelength range of 300 nm or more and 460 nm or less is used, and as the second luminous body, at least one kind of fluorescence having an emission peak in the wavelength range of 550 nm or more and 600 nm or less (yellow phosphor) and the phosphor of the present embodiment containing a crystal phase having the composition represented by [1] above.
(B) As the first luminous body, one having an emission peak in a wavelength range of 300 nm or more and 460 nm or less is used, and as the second luminous body, at least one kind of fluorescence having an emission peak in a wavelength range of 500 nm or more and 560 nm or less and a crystal phase having the composition represented by [1] above.
(C) As the first luminous body, one having an emission peak in a wavelength range of 300 nm or more and 460 nm or less is used, and as the second luminous body, at least one kind of fluorescence having an emission peak in a wavelength range of 550 nm or more and 600 nm or less (yellow phosphor), at least one phosphor (green phosphor) having an emission peak in the wavelength range of 500 nm or more and 560 nm or less, and a crystal phase having the composition represented by the above [1]. An embodiment using the phosphor of

Commercially available green or yellow phosphors can be used as the green or yellow phosphor in the above embodiment, and for example, garnet-based phosphors, silicate-based phosphors, nitride phosphors, oxynitride phosphors, and the like can be used.

(yellow phosphor)
Garnet-based phosphors that can be used for the yellow phosphor include, for example, (Y, Gd, Lu, Tb, La) ₃ (Al, Ga) ₅ O ₁₂ : (Ce, Eu, Nd), silicate-based phosphors For example, (Ba, Sr, Ca, Mg) ₂ SiO ₄ : (Eu, Ce), and for the nitride phosphor and oxynitride phosphor, for example, (Ba, Ca, Mg)Si ₂ O ₂ N ₂ : Eu (SION phosphor), (Li, Ca) ₂ (Si, Al) ₁₂ (O, N) ₁₆ : (Ce, Eu) (α-sialon phosphor), (Ca, Sr) AlSi ₄ (O, N) ₇ : (Ce, Eu) (1147 phosphor), (La, Ca, Y, Gd) ₃ (Al, Si) ₆ N ₁₁ : (Ce, Eu) (LSN phosphor), etc. be done.
These may be used individually by 1 type, and may be used in combination of 2 or more type.
Among the above phosphors, the yellow phosphor is preferably a garnet phosphor, and most preferably a YAG phosphor represented by Y ₃ Al ₅ O ₁₂ :Ce.

(green phosphor)
Examples of garnet-based phosphors that can be used as green phosphors include (Y, Gd, Lu, Tb, La) ₃ (Al, Ga) ₅ O ₁₂ : (Ce, Eu, Nd), Ca ₃ (Sc , Mg) _{2 Si 3} O ₁₂ : ₍ Ce, Eu) (CSMS phosphor). , Sr, Ca, Mg) ₂ SiO ₄ : (Ce, Eu) (BSS phosphor), and oxide phosphors such as (Ca, Sr, Ba, Mg) (Sc, Zn) ₂ O ₄ : ( Ce, Eu) (CASO phosphor), nitride phosphors and oxynitride phosphors include, for example, (Ba, Sr, Ca, Mg) Si ₂ O ₂ N ₂ : (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) ₆ O ₁₂ N ₂ : (Eu, Ce) (BSON phosphor), aluminate phosphor, for example, (Ba, Sr, Ca, Mg) ₂ Al ₁₀ O ₁₇ : (Eu, Mn) (GBAM phosphor), etc. is mentioned.
These may be used individually by 1 type, and may be used in combination of 2 or more type.

(red phosphor)
As the red phosphor, the phosphor of the present embodiment containing the crystal phase having the composition represented by the formula [1] is used. In addition to the phosphor of the present embodiment, for example, a Mn-activated fluoride phosphor , garnet-based phosphors, sulfide phosphors, nanoparticle phosphors, nitride phosphors, oxynitride phosphors, and other orange to red phosphors can be used. As other orange to red phosphors, for example, the following phosphors can be used.
Examples of Mn-activated fluoride phosphors include K ₂ (Si, Ti) F ₆ :Mn, K ₂ Si _1-x Na _x Al _x F ₆ : Mn (0<x<1) (collectively, KSF fluorescence (Sr,Ca)S:Eu (CAS phosphor) and La ₂ O ₂ S:Eu (LOS phosphor) as sulfide phosphors, and as garnet-based phosphors (Y , Lu, Gd, Tb) ₃ Mg ₂ AlSi ₂ O ₁₂ :Ce, nanoparticles such as CdSe, and nitride or oxynitride phosphors such as (Sr, Ca)AlSiN ₃ :Eu(S /CASN phosphor), (CaAlSiN ₃ ) _1-x ·(SiO ₂ N ₂ ) _x : Eu (CASON phosphor), (La, Ca) ₃ (Al, Si) ₆ N ₁₁ : Eu (LSN phosphor) , (Ca, Sr, Ba) ₂ Si 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 (M is Ca, Sr, etc.) (α-sialon phosphor), Li(Sr, Ba)Al ₃ N ₄ :Eu (the above x is 0<x<1) and the like.
These may be used individually by 1 type, and may be used in combination of 2 or more type.

[Structure of Light Emitting Device]
The light-emitting device according to this embodiment has a first light-emitting body (excitation light source), and includes a crystal phase having at least a composition represented by the above formula [1] as a second light-emitting body. can be used, the configuration is not limited, and any known device configuration can be used.
Embodiments of the device configuration and the light-emitting device include, for example, those described in Japanese Patent Application Laid-Open No. 2007-291352. Other forms of the light-emitting device include shell-type, cup-type, chip-on-board, remote phosphor, and the like.

{Use of light-emitting device}
The application of the light-emitting device is not particularly limited, and it can be used in various fields where ordinary light-emitting devices are used. can be used for
In addition, since it includes a red phosphor having a favorable emission wavelength, it can be used for a red vehicle indicator lamp or a white vehicle indicator lamp containing the red color.

[Lighting device]
In one embodiment, the present invention can be a lighting device including the light emitting device as a light source.
When the light-emitting device is applied to a lighting device, the specific configuration of the lighting device is not limited, and the light-emitting device as described above may be used by appropriately incorporating it into a known lighting device. 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 used.

[Image display device]
In one embodiment, the present invention can be an image display device including the light emitting device as a light source.
When the light emitting device is used as a light source of an image display device, the specific configuration of the image display device is not limited, but it is preferably used 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 is used as a backlight, and an optical shutter using liquid crystal and a color filter having red, green, and blue pixels are used. can be combined to form an image display device.

[Vehicle indicator light]
In one embodiment, the present invention can be a vehicle indicator lamp including the light emitting device.
The light-emitting device used in the vehicle indicator light is preferably a light-emitting device that emits white light in certain embodiments. A light-emitting device that emits white light has a deviation duv of -0.0200 to 0.0200 from the blackbody radiation locus of light color and a color temperature of 5000 K or more and 30000 K or less. is preferably
The light-emitting device used in the vehicle indicator light is preferably a light-emitting device that emits red light in certain embodiments. In this embodiment, for example, the light-emitting device may absorb blue light emitted from a blue LED chip and emit red light, thereby providing a red-light vehicular indicator lamp.
The vehicular indicator lamps include lights provided in a vehicle for the purpose of giving some kind of indication to other vehicles, people, etc., such as headlamps, side lamps, back lamps, turn signals, brake lamps, and fog lamps of the vehicle.

Hereinafter, the present invention will be described in more detail with experimental examples that replace the examples of the present invention, but the present invention is not limited to the following as long as it does not deviate from the gist of the present invention.

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

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

As examples of the present invention, red phosphors (Samples 1 to 5) corresponding to the phosphors of the present embodiment containing a crystal phase having the composition represented by the formula [1] were prepared. Further, as a comparison target with the present invention, Sample 6, which does not satisfy the above formula [1] because the content of Ca is 0, was prepared.
The composition, space group, emission peak wavelength, and half width of each sample are shown in Table 1 together with the literature values of SrLiAl ₃ N ₄ as a reference example. As a representative example, the XRD spectrum chart and emission spectrum chart of the phosphor of Sample 2 are shown in FIGS. 1 and 2, respectively.
Sample 2 has a good half-value width of 65 nm, and Ix/Iy and Iz/Iy in XRD are 0.194 and 0.216, respectively, and the phase purity is also good. When applied to a light-emitting device, the conversion efficiency is good. It can be seen that a light-emitting device with a high density can be obtained.

The phosphors of Samples 1 to 5 according to this experimental example all exhibit a space group of P42/m, and have an emission peak wavelength of 620 nm or more and 640 nm, which is ideal for color rendering or color reproducibility when used in a white LED. The range was as follows.

Next, results of a simulation relating to the characteristics of the light-emitting device including the phosphor that satisfies the formula [1] will be described.

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

As shown in Table 2, the light emitting device including the phosphor containing the crystal phase having the composition represented by the above formula [1] has a conversion efficiency, It can be seen that the color rendering property is excellent.

Also, the characteristics of the image display device using the white LED as a backlight were evaluated in the same simulation. A phosphor related to Sample 2 as a red phosphor, or a SCASN phosphor with an emission peak wavelength of 628 nm (Mitsubishi Chemical Co., Ltd., BR-102C), and a green phosphor, a β-SiAlON phosphor (Mitsubishi Chemical Co., BG-601 /K), and the chromaticity coordinates (x, y) after passing the light of the white LED through a color filter used in a general image display device (display etc.) are (0.3101, 0. 3162), and what percentage of the NTSC color gamut the color gamut that can be displayed by the LED device covers (hereinafter sometimes referred to as the coverage ratio) was calculated. Table 3 shows the results.

As shown in Table 3, the light-emitting device, the image display device, and the like, which include the phosphor containing the crystal phase having the composition represented by the formula [1], have higher conversion efficiency and color compared to the case of using the conventional red phosphor. It can be seen that the area coverage ratio is both excellent.

As described above, the phosphor containing the crystalline phase having the composition represented by the above formula [1] has a preferable wavelength for red color and an excellent half-value width. , a light-emitting device, a lighting device, an image display device, a vehicle indicator lamp, and the like, which are excellent in color rendering properties and other characteristics.

Claims (15)

A light-emitting device comprising 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 formula.
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) In the powder X-ray diffraction spectrum of the phosphor, 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. Then, 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 claim 1, wherein: 3. The light-emitting device according to claim 1, wherein 0.0≤y≤0.05 in the formula [1]. 4. The light-emitting device according to claim 1, wherein in the formula [1], MA is Ca. 5. The light-emitting device according to claim 1, wherein in the formula [1], 80 mol % or more of MB is Li. 6. The light-emitting device according to claim 1, wherein 80 mol % or more of MC in the formula [1] is Al. 7. The light-emitting device according to claim 1, wherein in the formula [1], 80 mol % or more of Re is Eu. The light emitting device according to any one of claims 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 the emission spectrum. The light-emitting device according to any one of claims 1 to 8, wherein the phosphor has an emission spectrum with a full width at half maximum (FWHM) of 70 nm or less. A light-emitting device according to any one of claims 1 to 9, further comprising a yellow phosphor and/or a green phosphor. 11. The light emitting device according to claim 10, wherein said yellow phosphor and/or green phosphor includes at least one of garnet phosphor, silicate phosphor, nitride phosphor, and oxynitride phosphor. . A first light emitter and a second light emitter that emits visible light when irradiated with light from the first light emitter, and the second light emitter has a composition represented by the formula [1] The light-emitting device according to any one of claims 1 to 11, comprising a phosphor containing a crystalline phase having a A lighting device comprising the light emitting device according to claim 12 as a light source. An image display device comprising the light emitting device according to claim 12 as a light source. A vehicle indicator lamp comprising the light emitting device according to claim 12 as a light source.

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