CN118043979A - Phosphor, light emitting device, illumination device, image display device, and display lamp for vehicle - Google Patents

Abstract

A phosphor containing a crystal phase having a composition represented by the following formula [1], and a light-emitting device .Re_x(Sr_1－yMA_y)_aMB_bMC_cN_dO_eX_f[1](MA provided with the phosphor are 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 one or more elements selected from Al, si, ga, in and Sc. X is one or more elements selected from F, cl, br and I. Re is one or more elements selected from Eu, ce, pr, tb and Dy. a. b, c, d, e, f, x, y satisfy the following formulas, respectively. A is more than or equal to 0.8 and less than or equal to 1.2, b is more than or equal to 1.4 and less than or equal to 2.6, c is more than or equal to 1.4 and less than or equal to 2.6, d is more than or equal to 1.1 and less than or equal to 2.9, e is more than or equal to 1.1 and less than or equal to 0.9, f is more than or equal to 0.0 and less than or equal to 0.1, x is more than or equal to 0.0 and less than or equal to 0.2, and y is more than or equal to 0.0 and less than or equal to 0.7.

Description

Phosphor, light-emitting device, lighting device, image display device, and vehicle display lamp

Technical Field

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

Background technique

In recent years, due to the trend of energy saving, the demand for lighting and backlight using LEDs has been increasing. The LEDs used here are white light emitting LEDs in which a phosphor is arranged on an LED chip that generates light of a blue or near-ultraviolet wavelength.

As this type of white light-emitting LED, in recent years, an LED obtained by using a nitride phosphor that emits red light using the 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. As LEDs, higher luminous efficiency is constantly being demanded, and light-emitting devices with phosphors that have excellent luminous properties as red phosphors are desired.

As red phosphors used in light-emitting devices, for example _, KSF phosphors represented by _the general formula _K2 (Si,Ti _{) F6} :Mn, _{K2Si1 - xNaxAlxF6} :Mn(0＜x＜1), CASN phosphors and SCASN phosphors represented by the general formula (Sr,Ca) _AlSiN3 :Eu are known. However, KSF phosphors are highly toxic substances activated by Mn, so phosphors that are more friendly to the human body and the environment are needed. In addition, since most of CASN phosphors and SCASN phosphors have a large half-peak width (FWHM) of about 80nm to 90nm, a new red phosphor with a smaller half-peak width is needed.

In addition, as a red phosphor that can be used in a light-emitting device in recent years, for example, Patent Document 1 describes in an example a phosphor represented by a composition formula of SrLiAl ₃ N ₄ :Eu and a light-emitting device using the same.

Prior art literature

Patent Literature

Patent Document 1: Japanese Patent No. 6335884

Summary of the invention

However, the peak emission wavelength of the phosphor described in Patent Document 1 is relatively long, at about 650 nm. Therefore, in addition to low visual sensitivity to red and reduced lumen equivalent (Lm/W) in the light-emitting device, there is a problem that color rendering or color reproducibility is easily reduced when used in lighting or displays.

In view of the above problems, an object of the present invention is to provide a novel red phosphor that emits light with good color rendering or color reproducibility, and a light-emitting device, a lighting device, an image display device, and a vehicle indicator lamp including the phosphor.

As a result of intensive studies, the present inventors have found that the above-mentioned problems can be solved by using a phosphor including a crystal phase represented by a specific composition or a light-emitting device including the phosphor, thereby completing the present invention.

That is, the present invention includes the following contents.

[1] A light-emitting device comprising a phosphor including 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 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,

a, b, c, d, e, f, x, and y respectively 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)

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

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

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

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

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

[8] The light-emitting device according to any one of [1] to [7], wherein the light-emitting device has a light-emitting peak wavelength in the range of 620 nm to 645 nm in the light-emitting spectrum.

[9] The light-emitting device according to any one of [1] to [8], wherein the full width at half maximum (FWHM) in the light-emitting spectrum is 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] A light-emitting device according to [10], wherein the yellow phosphor and/or the green phosphor comprises one or more of a garnet phosphor, a silicate phosphor, a nitride phosphor and a nitride oxide phosphor.

[12] A 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 by irradiating light from the first light-emitting body, wherein the second light-emitting body comprises: a phosphor having a crystalline phase having a composition represented by the above formula [1].

[13] A lighting device comprising the light-emitting device described in [12] as a light source.

[14] An image display device comprising the light-emitting device described in [12] as a light source.

[15] A vehicle indicator light having the light-emitting device described in [12] as a light source.

[16] A phosphor comprising 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 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,

a, b, c, d, e, f, x, and y respectively 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)

[17] A phosphor according to [16], wherein, in the powder X-ray diffraction pattern of the phosphor, when the peak intensity of (110) appearing in the region of 2θ=10 to 12 degrees is set to Ix, when the peak intensity of (121) appearing in the region of 2θ=37 to 39 degrees is set to Iy, 0＜Ix/Iy＜0.2, and when the peak intensity of (111) from the SrO phase of the impurity phase appearing in the region of 2θ=30 degrees is set to Iz, Iz/Iy＜0.25.

[18] The phosphor according to [16] or [17], wherein in the above formula [1], 0.0≤y≤0.05.

[19] The phosphor according to any one of [16] to [18], wherein in the above formula [1], MA is Ca.

[20] The phosphor according to any one of [16] to [19], wherein in the above formula [1], 80 mol % or more of MB is Li.

[21] The phosphor according to any one of [16] to [20], wherein in the above formula [1], 80 mol % or more of MC is Al.

[22] The phosphor according to any one of [16] to [21], wherein in the above formula [1], 80 mol % or more of Re is Eu.

[23] The phosphor according to any one of [16] to [22], which has a light emission peak wavelength in the range of 620 nm to 645 nm in the light emission spectrum.

[24] The phosphor according to any one of [16] to [23], wherein the full width at half maximum (FWHM) in the emission spectrum is 70 nm or less.

According to the present invention, it is possible to provide a novel red phosphor showing good luminescent color, a light emitting device having good color rendering properties, and a high-quality lighting device, image display device, and vehicle indicator lamp.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an XRD pattern of the phosphor of Example 2.

FIG. 2 is a light emission spectrum of the phosphor of Example 2.

FIG. 3 is a graph showing the light emission characteristics of the light emitting device simulated in the example.

Detailed ways

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.

It should be noted that the numerical range represented by "to" in this specification means a range that includes the numerical values recorded before and after "to" 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 indicated 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} ” means _{“ CaAl2O4} : _Eu ”, “ _{SrAl2O4 : Eu} ”, “ _BaAl2O4: Eu”, “Ca1 _{- xSrxAl2O4 : Eu} ”, “Sr1 _{-xBaxAl2O4 :} Eu”, “Ca1 _{- xBaxAl2O4 :} Eu”, and “Ca1 _{-x- ySrxBayAl2O4 :} Eu” (wherein 0＜x＜1, 0＜ _y ＜ ₁ , and 0＜x+y＜ ₁ ) are all included.

In one embodiment, the present invention is a phosphor including a crystal phase having a composition represented by the following formula [1].

In another embodiment, the present invention is a light-emitting device including the phosphor.

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 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,

a, b, c, d, e, f, x, and y respectively 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)

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

In formula [1], Sr represents strontium.

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

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.

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 or Si, more preferably contains Al, further preferably more than 80 mol% of MC is Al, and particularly preferably MC is Al.

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

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

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

As components other than those explicitly described, there can be mentioned an element having an atomic number different from the intentionally added element, an element of the same group as the intentionally added element, a rare earth element different from the intentionally added rare earth element, a halogen element when a halide is used as the Re raw material, and elements that may generally be contained as impurities in various raw materials.

As the case where components other than those clearly described are inevitably or unintentionally contained, for example, it is conceivable that the components are introduced from raw material impurities or during production processes such as pulverization steps and synthesis steps. In addition, as trace added components, reaction aids and Re raw materials can be cited.

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 each phosphor. In addition, y represents the molar content of MA when the total molar amount of Sr and MA is set to 1.

The value of a is usually 0.7 or more, preferably 0.8 or more, more preferably 0.85 or more, further preferably 0.9 or more, and is usually 1.3 or less, preferably 1.2 or less, more preferably 1.1 or less.

The values of b and c are each independently 1.4 or more, preferably 1.6 or more, more preferably 1.8 or more, and are 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 further preferably 0.02 or less.

The value of x is larger 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, and further preferably 0.08 or less.

When b, c, d, and e are within the above ranges, the crystal structure is stabilized. In addition, in order to achieve charge balance of the entire phosphor, the values of d, e, and f can be appropriately adjusted.

The value of y is larger than 0.0, usually 0.01 or more, preferably 0.05 or more, more preferably 0.1 or more, further preferably 0.2 or more, and usually 0.7 or less, preferably 0.6 or less, more preferably 0.5 or less, further preferably 0.4 or less.

When the value of y is within the above range, the crystal structure is stabilized and the phosphor has a good emission peak wavelength.

In addition, when the value of a is within the above range, the crystal structure is stabilized and a phosphor with less heterophase 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, further preferably 3.7 or more, and are preferably 5.0 or less, more preferably 4.6 or less, further preferably 4.3 or less.

When the values of b+c and d+e+f are within the above ranges, the crystal structure is stabilized.

If any content is within the above range, the emission peak wavelength and half-value width of the emission spectrum of the obtained phosphor are good and thus it is preferred.

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

[Particle size of crystal phase]

The particle size of the crystal phase of the phosphor of this embodiment is usually 2 μm to 35 μm in terms of the average particle size based on volume, and the lower limit is preferably 3 μm, more preferably 4 μm, and further preferably 5 μm. In addition, the upper limit is preferably 30 μm or less, more preferably 25 μm or less, further preferably 20 μm, and particularly preferably 15 μm. If the average particle size based on volume is above the lower limit, it is preferred from the perspective of the luminescent characteristics exhibited by the crystal phase in the LED package, and if it is below the upper limit, it is preferred from the perspective of avoiding noise blockage in the manufacturing process of the LED package.

The volume-based average particle size of the phosphor crystal phase can be measured by a laser particle size analyzer. The volume-based average particle size is defined as the particle size ( _d50 ) at which the relative particle amount on a volume basis of the particle size distribution (cumulative distribution) is 50% when the sample is measured using a particle size distribution measuring device based on the laser diffraction/scattering method.

{Physical properties of phosphors, etc.}

[Space Group]

The crystal system (space group) in the phosphor of the present embodiment is more preferably P42/m. The space group in the phosphor is not particularly limited as long as the average structure considered statistically exhibits a repetition period of the above-mentioned length within the range distinguishable by powder X-ray diffraction or single crystal X-ray diffraction, and is preferably a space group belonging to the 84th species based on "International Tables for Crystallography (Third, revised edition), Volume ASPACE-GROUP SYMMETRY".

Due to the above-mentioned space group, the full width at half maximum (FWHM) in the emission spectrum becomes small, and a phosphor with good emission efficiency can be obtained.

Here, the space group can be determined 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, and the like.

In the powder X-ray diffraction pattern of the above-mentioned phosphor in the present embodiment, the peak intensity of (110) appearing in the region of 2θ=10 to 12 degrees is set to Ix, the peak intensity of (121) appearing in the region of 2θ=37 to 39 degrees is set to Iy, and the peak intensity of (111) from the impurity phase SrO phase appearing in the region of 2θ=30 degrees is set to Iz. The relative intensity of Ix when Iy is 1, i.e., Ix/Iy, is usually less than 0.3, preferably less than 0.25, more preferably less than 0.2, and further preferably less than 0.15. In addition, it is usually greater than 0, but the smaller the better.

In addition, the relative intensity of Iz when Iy is 1, i.e., Iz/Iy, is usually 0.5 or less, preferably 0.4 or less, more preferably 0.3 or less, further preferably 0.25 or less, particularly preferably 0.2 or less, and particularly preferably 0.15 or less. In addition, it is usually 0 or more, but the smaller the better.

The above-mentioned (121) peak is one of the characteristic peaks observed when the crystal system (space group) is P42/m. Since Iy is relatively high, a phosphor with higher P42/m phase purity can be obtained.

By setting Ix/Iy or Iz/Iy to be below the above upper limit, the luminous efficiency of the light-emitting device is improved because the phosphor has high phase purity and a small half-value width (FWHM).

[Characteristics of luminescence spectrum]

The phosphor of this embodiment is a red phosphor that exhibits good luminescent color. That is, it is excited by irradiation with light having an appropriate wavelength, and emits red light that exhibits good luminescent peak wavelength and half-maximum width (FWHM) in the luminescent spectrum. The luminescent spectrum and the excitation wavelength, luminescent peak wavelength, and half-maximum width (FWHM) involved in its measurement are described below.

(Excitation wavelength)

The 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 500 nm or less, preferably 480 nm or less, more preferably 460 nm or less, that is, it is excited by light in the near-ultraviolet to blue region.

It should be noted that the shape of the luminescence spectrum and the description of the luminescence peak wavelength and half-width described below can be applied independently of the excitation wavelength, but 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.

(Emission peak wavelength)

The peak wavelength in the luminescence spectrum of the phosphor of the present embodiment is usually above 620nm, preferably above 625nm, and more preferably above 630nm. In addition, the peak wavelength in the luminescence spectrum is usually below 649nm, preferably below 645nm, and more preferably below 640nm.

By setting the peak wavelength in the emission spectrum of the phosphor to be within the above range, the emission color is good red, and by using such a phosphor in a light-emitting device, a light-emitting device with good color rendering or color reproducibility can be provided. In addition, by setting the peak wavelength in the emission spectrum of the phosphor to be below the above upper limit, a light-emitting device with good red visual sensitivity and good lumen equivalent lm/W can be provided.

(Half-maximum width of the luminescence spectrum)

In the above-mentioned phosphor of this embodiment, the half-width of the luminescence peak in the luminescence spectrum is usually less than 80nm, preferably less than 70nm, more preferably less than 60nm, further preferably less than 55nm, particularly preferably less than 50nm, and is usually more than 10nm.

By setting the half-value width of the emission peak to be within the above range, when used in an image display device such as a liquid crystal display, the color reproduction range of the image display device can be expanded without reducing the color purity.

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

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

<Method for producing phosphor>

The phosphor of the present 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] and heating the mixture.

The raw materials of each element (Sr, MA, MB, MC, Re) are not particularly limited, and examples thereof include monomers, oxides, nitrides, hydroxides, halides such as chlorides and fluorides, inorganic salts such as sulfates, nitrates, and phosphates, and organic acid salts such as acetates. In addition, compounds containing two or more of the above-mentioned element groups may also be used. In addition, each compound may also be a hydrate, etc.

In addition, in the examples described below, Sr ₃ N ₂ , CA ₃ N ₂ , Li ₃ N, AlN, Al ₂ O ₃ and EuF ₃ or Eu ₂ O ₃ are used as starting materials.

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

The purity of each raw material is not particularly limited, but from the viewpoint 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 90 mol% or more, preferably 95 mol% or more, more preferably 97 mol% or more, and further preferably 99 mol% or more. The upper limit is not particularly limited, but is usually 100 mol% or less, and may also include impurities that are inevitably mixed in.

In the examples described below, raw materials having a purity of 95 mol % or more were used.

Oxygen (O), nitrogen (N), and halogen (X) elements can be supplied by using oxides, nitrides, halides, and the like as raw materials of the above-mentioned elements, or they can be appropriately contained by setting an atmosphere containing oxygen or nitrogen during the synthesis reaction.

[Mixing process]

The mixing method of the raw materials is not particularly limited, and conventional methods can be used. For example, the phosphor raw materials are weighed to obtain the 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.

(a) A dry mixing method in which the above-mentioned phosphor raw materials are ground and mixed by combining grinding using a dry grinding machine such as a hammer mill, roller mill, ball mill, jet mill, or mortar and pestle, and mixing using a screw mixer, V-type mixer, Henschel mixer, or mortar and pestle.

(b) A wet mixing method in which a solvent or dispersion medium such as water is added to the above-mentioned phosphor raw materials, 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.

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 preferred.

In addition, method (a) was adopted in the Examples mentioned later.

[Heating process]

In the heating 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 700°C to 1200°C, preferably 750°C to 1000°C.

The material of the crucible is preferably a material that does not react with the phosphor raw material or reactant, and may include ceramics such as alumina, quartz, boron nitride, silicon carbide, silicon nitride, and metals such as nickel, platinum, molybdenum, tungsten, tantalum, niobium, iridium, and rhodium, or alloys containing these as main components. In the examples described below, a nickel crucible is used.

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.

In the heating process, heating is performed within the above-mentioned temperature range for usually 1 hour to 400 hours, preferably 5 hours to 150 hours, and preferably 10 to 120 hours. In addition, this heating process can be performed once or divided into multiple times. As a method of dividing into multiple times, there can be cited a method including an annealing process under pressure for repairing defects, a method of secondary heating after a primary particle or intermediate is obtained to obtain a secondary particle or a final product, etc. .

In this way, the phosphor of this embodiment is obtained.

＜Light-emitting device＞

In another embodiment, the present invention is a light-emitting device comprising a first light-emitting body (excitation light source) and a second light-emitting body that emits visible light by irradiating light from the first light-emitting body, and as the second light-emitting body, a light-emitting device comprising a phosphor of the present embodiment is provided, wherein the phosphor comprises a crystalline phase having a composition represented by the above formula [1]. Here, the second light-emitting body may be used alone or in any combination and ratio.

The light-emitting device in this embodiment includes, as the second light-emitting body, the phosphor of this embodiment, which includes a crystal phase having a composition represented by the above formula [1], and further, under the irradiation of light from an excitation light source, a phosphor that produces fluorescence in the yellow, green or red region (orange or red) can be used. Specifically, when constituting a light-emitting device, as a yellow phosphor, it is preferred that the phosphor has a luminescence peak in the wavelength range of 550nm to 600nm, and as a green phosphor, it is preferred that the phosphor has a luminescence peak in the wavelength range of 500nm to 560nm. In addition, the orange or red phosphor has a luminescence peak in a wavelength range of generally 615nm or more, preferably 620nm or more, more preferably 625nm or more, further preferably 630nm or more, generally 660nm or less, preferably 650nm or less, more preferably 645nm or less, and further preferably 640nm or less.

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.

Below, as a red phosphor, a method of a light-emitting device is described in which the phosphor of this embodiment is used, which includes a crystal phase having a composition represented by the above formula [1] and has a light-emitting peak in the wavelength range of 620nm to 645nm, and the first light-emitting body is a phosphor having a light-emitting peak in the wavelength range of 300nm to 460nm, but this embodiment is not limited to these.

In the above case, the light emitting device of this embodiment may be, for example, the following (A), (B) or (C).

(A) A method of using a luminescent material having a luminescence peak in the wavelength range of 300 nm to 460 nm as the first luminescent body, and using at least one phosphor (yellow phosphor) having a luminescence peak in the wavelength range of 550 nm to 600 nm and the phosphor of this embodiment including a crystalline phase having the composition represented by [1] above as the second luminescent body.

(B) A method of using a luminescent material having a luminescent peak in the wavelength range of 300 nm to 460 nm as the first luminescent body, and using at least one phosphor (green phosphor) having a luminescent peak in the wavelength range of 500 nm to 560 nm and the phosphor of this embodiment including a crystalline phase having the composition represented by the above [1] as the second luminescent body.

(C) A method of using a luminescent material having a luminescent peak in the wavelength range of 300nm to 460nm as the first luminescent body, and using at least one phosphor (yellow phosphor) having a luminescent peak in the wavelength range of 550nm to 600nm, at least one phosphor (green phosphor) having a luminescent peak in the wavelength range of 500nm to 560nm, and the phosphor of this embodiment including a crystalline phase having the composition represented by the above [1] as the second luminescent body.

As the green or yellow phosphor in the above-mentioned embodiment, a commercially available phosphor can be used, for example, a garnet-based phosphor, a silicate-based phosphor, a nitride phosphor, a nitride oxide phosphor, etc. can be used.

(Yellow phosphor)

Examples of garnet-based phosphors that can be used as yellow phosphors include (Y, Gd, Lu, Tb, La) ₃ (Al, Ga) ₅ O ₁₂ :(Ce, Eu, Nd); examples of silicate-based phosphors include (Ba, Sr, Ca, Mg) ₂ SiO ₄ :(Eu, Ce); examples of nitride phosphors and oxynitride phosphors include (Ba, Ca, Mg) Si ₂ O ₂ N ₂ :Eu (SION-based 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), and (La, Ca, Y, Gd) ₃ (Al, Si) ₆ N ₁₁ :(Ce, Eu) (LSN phosphor).

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

As the yellow phosphor, among the above phosphors, a garnet-based phosphor is preferred, and among them, a YAG-based phosphor represented by Y ₃ Al ₅ O ₁₂ :Ce is most preferred.

(Green phosphor)

Examples of garnet-based phosphors that can be used as green phosphors include (Y, Gd, Lu, Tb, La) ₃ (Al, Ga) _{5O12 :} (Ce, Eu, Nd) and _Ca3 (Sc, Mg) _{2Si3O12 :} (Ce _, Eu) (CSMS phosphors). Examples of silicate-based phosphors include (Ba, Sr, Ca, Mg) _{3SiO10 :} (Eu, Ce) and (Ba, Sr, Ca, Mg) _2SiO4 :(Ce, Eu) ₍ BSS phosphors). Examples of oxide phosphors include (Ca, Sr, Ba, Mg)(Sc, Zn) _{2O4 :} (Ce, Eu) (CASO phosphors). Examples of nitride phosphors and oxynitride phosphors include (Ba, Sr, Ca, Mg) _Si2O2N2 :(Eu, Ce) _{and Si6 - zAl2O3} :(Eu, _Ce ). _{OzN8 -z} :(Eu, Ce) (β-sialon phosphor) (0<z≤1), (Ba, Sr, Ca, Mg, La) ₃ (Si, Al) _{6O12N2 :} (Eu, Ce) (BSON phosphor), and examples of aluminide phosphors include (Ba, Sr, Ca, Mg) _{2Al10O17 :} (Eu, _Mn ) ( _GBAM -based phosphor).

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

(Red phosphor)

As the red phosphor, the phosphor of the present embodiment including a crystal phase having a composition represented by the above formula [1] is used, but in addition to the phosphor of the present embodiment, other orange or red phosphors such as Mn-activated fluoride phosphors, garnet-based phosphors, sulfide phosphors, nanoparticle phosphors, nitride phosphors, and oxynitride phosphors can also be used. As other orange or red phosphors, for example, the following phosphors can be used.

Examples of the Mn-activated fluoride phosphor include _K2 (Si,Ti) _F6 :Mn and _{K2Si1 -xNAxAlxF6 : Mn} (0<x<1) (collectively referred to as KSF phosphors). Examples of the sulfide phosphor include (Sr,Ca)S:Eu (CAS phosphor) and _{La2O2S :} Eu (LOS phosphor). Examples of the garnet-based phosphor include (Y,Lu,Gd,Tb) _{3Mg2AlSi2O12 :} Ce. Examples of the nanoparticles include CdSe. Examples of the _nitride or _oxynitride phosphor include (Sr,Ca) _AlSiN3 :Eu (S/CASN phosphor), ( _CaAlSiN3 ) _1-x ·( _SiO2N2 ) _x :Eu (CASON phosphor), and (La,Ca) ₃ (Al,Si) _6N3 : _Eu (CASON phosphor) _{. 11} : Eu (LSN phosphor) _{, (Ca, Sr, Ba)2Si5 (} N, O) ₈ : Eu (258 phosphor), (Sr, Ca)Al1 _{+ xSi4- xOxN7 -x} : Eu (1147 phosphor), _Mx (Si, Al) ₁₂ (O, N) ₁₆ : Eu (M is Ca, Sr, etc.) (α-sialon phosphor), Li(Sr, Ba _{) Al3N4} : Eu (x in the above is 0＜x＜1), etc.

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

[Configuration of light emitting device]

The light-emitting device involved in this embodiment has a first light-emitting body (excitation light source), and, as a second light-emitting body, at least a phosphor of this embodiment including a crystal phase having a composition represented by the above formula [1] can be used. Its structure is not limited and any known device structure can be adopted.

As embodiments of the device configuration and the light emitting device, for example, there are those described in Japanese Patent Application Laid-Open No. 2007-291352. Also, as the form of the light emitting device, there are bullet type, cup type, chip on board, remote phosphor, and the like.

{Purpose of the light-emitting device}

The use of the light-emitting device according to this embodiment is not particularly limited, and the device can be used in various fields in which light-emitting devices are generally used. However, due to its high color rendering index, the device is particularly preferably used as a light source for a lighting device or an image display device.

Furthermore, since the red phosphor having a good light emission wavelength is provided, the present invention can be used in a red vehicle indicator lamp or a vehicle indicator lamp including white light of the red color.

[Lighting device]

In one embodiment of the present invention, a lighting device may include the above-mentioned light-emitting device as a light source.

When the light emitting device is applied to a lighting device, the specific structure of the lighting device is not limited, and the light emitting device can be appropriately installed in a known lighting device for use. For example, a light emitting lighting device can be cited in which a plurality of light emitting devices are arranged on the bottom surface of a holding housing.

[Image display device]

In one embodiment of the present invention, it can be used as an image display device using the above-mentioned 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 structure of the image display device is not limited, and it is preferably used together with a color filter. For example, as an image display device, in the case of a color image display device using a color liquid crystal display element, the light emitting device can be used as a backlight, and a light shutter of a liquid crystal and a color filter having red, green, and blue pixels can be combined to form an image display device.

[Vehicle indicator lights]

In one embodiment of the present invention, a vehicle indicator lamp including the above-mentioned light emitting device may be provided.

In a specific embodiment, the light emitting device used in the vehicle indicator lamp is preferably a light emitting device that emits white light. The light emitting device that emits white light preferably has a color point difference duv of -0.0200 to 0.0200 between the light emitted from the light emitting device and the black body radiation light, and a color temperature of 5000K to 30000K.

In a specific embodiment, the light emitting device used in the vehicle indicator lamp is preferably a light emitting device that emits red light. In this embodiment, for example, the light emitting device can be used as a red vehicle indicator lamp by absorbing blue light irradiated from a blue LED chip and emitting red light.

Vehicle display lights include the vehicle's headlights, side lights, reversing lights, indicator lights, brake lights, fog lights, and other lights that are set on the vehicle to provide certain instructions to other vehicles, people, etc.

Example

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples unless it departs from the gist of the present invention.

{test methods}

[Powder X-ray diffraction measurement]

Powder X-ray diffraction (XRD) was accurately measured using a powder X-ray diffraction apparatus SmartLab 3 (manufactured by Rigaku Corporation).

The measurement conditions are as follows.

Using CuKα tubes

X-ray output = 40kV, 200mA

Diverging slits = automatic

Detector = High-speed one-dimensional X-ray detector (D/teX Ultra 250)

Scanning range 2θ＝5～80 degrees

Reading width = 0.02 degrees

[Measurement of luminescence spectrum]

The phosphor was irradiated with light having a wavelength of 365 nm using a xenon lamp, and the emission spectrum in the wavelength region of 450 to 800 nm was measured using a fluorescence spectrophotometer.

[Examples 1 to 5, Comparative Example 1, Reference Example 1]

In Examples 1 to 5, red phosphors (Samples 1 to 5) having the compositions shown in Table 1 below were manufactured according to the method for manufacturing the phosphor of the present embodiment described above.

In addition, as Comparative Example 1, a red phosphor of Sample 6 was manufactured which did not satisfy the above formula [1] because the Ca content was 0.

The composition, space group, emission peak wavelength and half-value width of each phosphor are shown in Table 1. In addition, as Reference Example 1, the literature value of SrLiAl ₃ N ₄ is also shown in Table 1.

In addition, as a representative example, the XRD spectrum and the luminescence spectrum of the phosphor of Example 2 are shown in Figures 1 and 2, respectively. The half-peak width of the phosphor of Example Sample 2 is good, which is 65nm, and the purity of the Ix/Iy and Iz/Iy phases in XRD is also good, which are 0.194 and 0.216, respectively. When applied to a light-emitting device, a light-emitting device with good conversion efficiency can be obtained.

The space groups of the phosphors of Samples 1 to 5 involved in this example all show P42/m, and the emission peak wavelengths are in the ideal range of 620 nm to 640 nm in terms of color rendering or color reproducibility when used for white LEDs.

Next, the simulation results of the characteristics of the light-emitting device including the above-mentioned phosphor satisfying the formula [1] according to the example are described.

The emission spectrum of a white LED was derived according to the above method. The white LED has: the phosphor of Example 2 or the SCASN phosphor with a peak emission wavelength of 628nm (Mitsubishi Chemical Corporation, BR-102C) as a red phosphor, and the LuAG phosphor (Mitsubishi Chemical Corporation, BG-801/A4) as a green phosphor. All simulations were performed assuming a blue LED chip that emits 449nm light. In addition, the amounts of green phosphor and red phosphor were adjusted so that the chromaticity coordinates coincided with the coordinates of white light of 3000K to 8000K on the Planck curve, and the characteristics at various color temperatures were compared. The results are shown in Figures 3(a) to (f). In addition, the color rendering index Ra, the red color rendering index R9, and the conversion efficiency (LER) were calculated from each spectrum, and the results are shown in Table 2.

It should be noted that the “relative value of phosphor mass” in Table 2 refers to the mass ratio of phosphors of various colors when the total mass of the red phosphor + the green phosphor is 100%.

[Table 2]

As shown in Table 2, a light-emitting device including a phosphor having a crystal phase having a composition represented by the above formula [1] has excellent conversion efficiency and color rendering properties in a wider color temperature range than a light-emitting device using a conventional red phosphor.

In addition, in the same simulation, the characteristics of the image display device using the above-mentioned white LED as a backlight were evaluated. The phosphor involved in Example 2 (Sample 2) or the SCASN phosphor (Mitsubishi Chemical Corporation, BR-102C) with a peak emission wavelength of 628nm is used as a red phosphor, and the β-sialon phosphor (Mitsubishi Chemical Corporation, BG-601/K) is used as a green phosphor. The conversion efficiency when the chromaticity coordinates (x, y) of the light of the above-mentioned white LED are adjusted to (0.3101, 0.3162) after passing through the color filter used in a general image display device (display, etc.), and the result of calculating how many percentages of the color gamut that the LED device can display covers the color gamut of NTSC (hereinafter sometimes referred to as coverage) are shown in Table 3.

[table 3]

As shown in Table 3, the light-emitting device and image display device according to the examples having a phosphor including a crystal phase having a composition represented by the above formula [1] have excellent conversion efficiency and color gamut coverage compared to the case of using conventional red phosphors.

As described above, a phosphor including a crystal phase having a composition represented by the above formula [1] has a wavelength that is preferred for red and an excellent half-value width. By using a light-emitting device having such a phosphor, a light-emitting device, a lighting device, an image display device, a vehicle indicator lamp, etc. that have excellent color rendering and other characteristics can be provided.

Although the present invention has been described in detail using specific forms, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the invention.

This application is based on Japanese Patent Application No. 2021-166903 filed on October 11, 2021, and Japanese Patent Application No. 2021-166904 filed on October 11, 2021, the entire contents of which are incorporated by reference.

Claims (24)

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－yMA_y)_aMB_bMC_cN_dO_eX_f[1]

In the above-mentioned formula [1],

MA contains more than one element selected from Ca, ba, na, K, Y, gd and La,

MB contains one or more elements selected from Li, mg and Zn,

MC contains more than one element selected from Al, si, ga, in and Sc,

X contains more than one element selected from F, cl, br and I,

Re contains one or more elements selected from Eu, ce, pr, tb and Dy,

A. b, c, d, e, f, x, y satisfy the following formulas respectively,

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. The light-emitting device according to claim 1, wherein, in a powder X-ray diffraction pattern of the phosphor, when a peak intensity of (110) occurring in a region of 2θ=10 to 12 degrees is set to Ix, a peak intensity of (121) occurring in a region of 2θ=37 to 39 degrees is set to Iy, 0 < Ix/Iy < 0.2, and a peak intensity of (111) from an impurity phase SrO phase occurring in a region of 2θ=30 degrees is set to Iz, iz/Iy < 0.25.

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

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

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

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

7. The light-emitting device according to any one of claims 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 claims 1 to 7, wherein the light-emitting spectrum has a light-emission peak wavelength in a range of 620nm to 645 nm.

9. The light-emitting device according to any one of claims 1 to 8, wherein a full width at half maximum, FWHM, in an emission spectrum is 70nm or less.

10. The 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 the yellow phosphor and/or the green phosphor contains any one or more of a garnet-based phosphor, a silicate-based phosphor, a nitride phosphor, and a oxynitride phosphor.

12. The light-emitting device according to any one of claims 1 to 11, wherein the light-emitting device comprises a first light-emitting body and a second light-emitting body which emits visible light by irradiation with light from the first light-emitting body, and wherein the second light-emitting body comprises: a phosphor containing a crystal phase having a composition represented by the formula [1 ].

13. A lighting device provided with the light-emitting device according to claim 12 as a light source.

14. An image display device provided with the light-emitting device according to claim 12 as a light source.

15. A display lamp for a vehicle, comprising the light-emitting device according to claim 12 as a light source.

16. A phosphor comprising a crystal phase having a composition represented by the following formula [1],

Re_x(Sr_1－yMA_y)_aMB_bMC_cN_dO_eX_f[1]

In the above-mentioned formula [1],

MA contains more than one element selected from Ca, ba, na, K, Y, gd and La,

MB contains one or more elements selected from Li, mg and Zn,

MC contains more than one element selected from Al, si, ga, in and Sc,

X contains more than one element selected from F, cl, br and I,

Re contains one or more elements selected from Eu, ce, pr, tb and Dy,

A. b, c, d, e, f, x, y satisfy the following formulas respectively,

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。

17. The phosphor according to claim 16, wherein 0 < Ix/Iy < 0.2, when a peak intensity of (110) occurring in a region of 2θ=10 to 12 degrees is set to Ix, a peak intensity of (121) occurring in a region of 2θ=37 to 39 degrees is set to Iy, and a peak intensity of (111) from an impurity phase SrO phase occurring in a region of 2θ=30 degrees is set to Iz, iz/Iy < 0.25 in a powder X-ray diffraction spectrum of the phosphor.

18. The phosphor according to claim 16 or 17, wherein in the formula [1], 0.0.ltoreq.y.ltoreq.0.05.

19. The phosphor according to any one of claims 16 to 18, wherein MA is Ca in the formula [1 ].

20. The phosphor according to any one of claims 16 to 19, wherein 80 mol% or more of MB in the formula [1] is Li.

21. The phosphor according to any one of claims 16 to 20, wherein 80 mol% or more of MC in the formula [1] is Al.

22. The phosphor according to any one of claims 16 to 21, wherein 80 mol% or more of Re in the formula [1] is Eu.

23. The phosphor according to any one of claims 16 to 22, wherein a light emission spectrum has a light emission peak wavelength in a range of 620nm to 645 nm.

24. The phosphor according to any one of claims 16 to 23, wherein a full width at half maximum (FWHM) in an emission spectrum is 70nm or less.