JP6962569B2 - A phosphor and a phosphor-containing composition using the same, and a light emitting device, a lighting device, and an image display device using these. - Google Patents

Description

The present invention relates to a novel phosphor, a phosphor-containing composition using the same, a light emitting device, a lighting device, an image display device, and the like using these.

In recent years, in response to the trend of energy saving, the demand for lighting using LEDs, backlights, and the like is increasing in devices using light emitting devices such as image display devices and lighting devices. As the LED used for these, a white light emitting LED that emits white light by using an LED chip that emits light in the near ultraviolet or short wavelength visible region and a phosphor is becoming popular. In particular, a phosphor that emits red fluorescence (hereinafter, appropriately referred to as "red phosphor") is used in a light emitting device for an image display device or a lighting device, and its light emitting characteristics have been variously improved. Of these, in order to improve efficiency and color rendering properties, the development of phosphors with a narrow half-value width in a specific wavelength band is required, and in recent years, the value of the special color rendering index R9, which indicates the appearance of the red region, has been increased. It is regarded as important.

In order to achieve the special color rendering index R9, for example, it is effective to use a phosphor having an emission peak wavelength of 590 nm or more and less than 780 nm and a half width of 1 nm or more and 130 nm or less. Therefore, conventionally, a red phosphor having such a light emitting property has been developed.

For example, Patent Document 1 ^{discloses a Mn 4+} activated fluoride complex phosphor _{such as K 2} SiF ₆ : Mn ⁴⁺ (KSF). Further, Patent Document 2 discloses a light emitting device using KSF. Further, Patent Document 3 ^{discloses an Eu 3+} active acid sulfide phosphor _{such as L 2} O ₂ S: Eu ³⁺ (LOS).

U.S. Pat. No. 7,497973 U.S. Pat. No. 3,576,756 Japanese Patent No. 4433847

As described above, various red phosphors have been developed, but a red phosphor having further improved emission characteristics is desired.

The present invention has been made in view of the above problems. That is, an object of the present invention is to provide a novel phosphor having a crystal structure different from that of a conventional phosphor and emitting red light, a phosphor-containing composition using the same, and the like. Another object of the present invention is to provide a light emitting device using the red phosphor, a lighting device including the light emitting device, an image display device, and the like.

As a result of diligent studies on a new search for a phosphor to solve the above problems, the present inventors have a crystal structure different from that of the conventional red phosphor, and the light turns red by light in the near-ultraviolet or short wavelength visible region. We have found a novel phosphor that emits light, and have completed the present invention.

That is, the present invention provides various specific aspects shown below.
<1> M element, Li, Mg, and N (However, the M element is at least one or more activating element selected from the group consisting of Eu, Ce, Pr, Sm, Tb, Dy, and Yb). It is a phosphor containing a crystal phase having, and the crystal phase is characterized in that the cubic space group has a crystal structure belonging to F-43 m and the lattice constant satisfies the following range. body.
4.486 [Å] ≤ lattice constant a ≤ 5.483 [Å]

<2> The phosphor according to <1>, wherein the crystal phase further has O and is represented by the following formula [1].
_{M a Li 2-x Mg x} N y-z O z [1]
(In the above formula [1], a, x, y, and z are values that independently satisfy the following formula.
0 ≤ a ≤ 0.1
0 <x ≦ 1.25
0.67 ≤ y ≤ 1.1
0 ≦ z ≦ 0.1
0.67 ≤ yz ≤ 1.1)

<3> The crystal phase further has O and X elements (provided that the X element is at least one or more elements selected from the group consisting of Ca, Sr, and Ba and / or F). The phosphor according to <1>, which is represented by the following formula [2].
_{M a Li 2-x Mg x} N y-z O z X b [2]
(In the above formula [2], a, b, x, y, and z are values that independently satisfy the following formula.
0 ≤ a ≤ 0.1
0 <x ≦ 1.25
0.67 ≤ y ≤ 1.1
0 ≦ z ≦ 0.1
0 ≦ b ≦ 0.01
0.67 ≤ yz ≤ 1.1)

<4> The phosphor according to any one of <1> to <3>, wherein the M element contains Eu.
<5> When irradiated with excitation light having a wavelength of 300 nm or more and 480 nm or less, the emission peak wavelength is in the range of 610 to 640 nm, and the half width of the emission peak wavelength is 1 to 20 nm. , The phosphor according to any one of <1> to <4>.
<6> The phosphor according to any one of <2> to <5>, wherein 0 <a ≦ 0.01 and 0 ≦ z ≦ 0.09 in the above formula.
<7> The phosphor according to any one of <3> to <6>, wherein the content ratio of the X element in terms of element amount is 1500 ppm or less in total.
<8> The fluorescent substance according to any one of <1> to <7> is contained, and the fluorescent substance is contained in an amount of 20% by mass or more based on the total amount.
Fluorescent compound-containing composition.

<9> The phosphor comprises at least an excitation light source that emits excitation light having a wavelength of 300 nm or more and 480 nm or less, and a phosphor that converts at least a part of the light emitted by the excitation light source into a different emission spectrum. A light emitting device comprising at least the fluorescent substance according to any one of 1> to <7> and / or the fluorescent substance-containing composition according to <8>.
<10> A lighting device comprising the light emitting device according to <9>.
An image display device comprising the light emitting device according to <11> and <9>.

According to the present invention, it is possible to realize a novel phosphor having a crystal structure different from that of a conventional phosphor and emitting red light, a phosphor-containing composition using the same, and the like. This novel phosphor is particularly useful as a light emitting material for white light emitting LED applications and the like due to its light emitting characteristics (excitation spectrum, light emitting spectrum, light emitting color, luminous efficiency). Therefore, the light emitting device containing the novel phosphor or the phosphor-containing composition of the present invention, and the lighting device and the image display device including the light emitting device are highly efficient and of high quality.

It is a graph which shows the excitation spectrum and the emission spectrum of the phosphor of Example 1, the broken line in the figure represents an excitation spectrum, and the solid line represents an emission spectrum.

Hereinafter, embodiments of the present invention will be described in detail. The following embodiments are examples (representative examples) of embodiments of the present invention, and the present invention is not limited thereto. Further, the present invention can be arbitrarily modified and implemented without departing from the gist thereof. The numerical range represented by using "~" in the present specification means a range including the numerical values before and after "~" as the lower limit value and the upper limit value. For example, the numerical range of "1 to 100" includes both the lower limit value "1" and the upper limit value "100". The same applies to the notation of other numerical ranges.

Further, in the composition formulas of the phosphors in the present specification, the delimiters of each composition formula are represented by separating them with commas (,). When a plurality of elements are listed separated by a comma (,), it is indicated that one or more of the listed elements may be contained in any combination and ratio. For example, the composition formula "(Ca, Sr, Ba) Al ₂ O ₄ : Eu" is "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", "Ca _1-x Ba _x Al ₂ O ₄ : Eu", _{"Ca 1-x-y Sr x} Ba y Al 2 O 4: Eu " (. However, in these formulas, is 0 <x <1,0 <y < 1,0 <x + y <1) and a comprehensive It shall be shown as.

<Fluorescent material>
The phosphor of the present embodiment is a phosphor containing a crystal phase having M element, Li, Mg, and N, and the crystal phase has a crystal structure in which the cubic space group belongs to F-43 m. However, it is characterized in that the lattice constant satisfies the following range.
4.486 [Å] ≤ lattice constant a ≤ 5.483 [Å]

Here, the M element is an activating element and is a group consisting of europium (Eu), cerium (Ce), praseodymium (Pr), samarium (Sm), terbium (Tb), dysprosium (Dy), and ytterbium (Yb). Represents one or more elements selected from. The M element preferably contains at least Eu, and more preferably Eu. In addition, Eu may be replaced with one or more elements selected from the group consisting of Ce, Pr, Sm, Tb, Dy and Yb in whole or in part. That is, it is preferable that the M element contains Eu and at least one or more elements selected from the group consisting of Ce, Pr, Sm, Tb, Dy and Yb. From the viewpoint of emission quantum efficiency, Eu and Ce are more preferable, and the M element is more preferably Eu and / or Ce, and more preferably Eu. The content ratio of Eu to the entire M element is not particularly limited, but is preferably 50 mol% or more, more preferably 70 mol% or more, and particularly preferably 90 mol% or more.

Li represents lithium. Li may be partially substituted with other monovalent elements such as sodium (Na), potassium (K), rubidium (Rb), cesium (Cs) and the like. These contents are not particularly limited as long as the effects of the present embodiment are not impaired, but are preferably 50 mol% or less, more preferably 30 mol% or less, and preferably 10 mol% or less. Especially preferable.

Mg represents magnesium. Mg may be partially substituted with a divalent metal element other than the alkaline earth metal element, for example, zinc (Zn) or the like. These contents are not particularly limited as long as the effects of the present embodiment are not impaired, but are preferably 50 mol% or less, more preferably 30 mol% or less, and preferably 10 mol% or less. Especially preferable.

N represents nitrogen (element). Nitrogen may be partially substituted with other elements such as oxygen (O), halogen atom (fluorine (F), chlorine (Cl), bromine (Br), iodine (I)) and the like. Further, it may be defective in the crystal to cause a lattice defect in the crystal structure. These contents are not particularly limited as long as the effects of the present embodiment are not impaired, but are preferably 10 mol% or less, more preferably 5 mol% or less, and preferably 1 mol% or less. preferable.

The phosphor of the present embodiment may contain other elements in addition to the above-mentioned minimum constituent elements. Other elements include oxygen (O); halogen atoms such as fluorine atom (F), chlorine atom (Cl), bromine atom (Br), iodine atom (I); calcium (Ca), strontium (Sr), barium. Examples thereof include alkaline earth metals such as (Ba), but the present invention is not particularly limited thereto. Oxygen is not only mixed as an impurity in the raw material metal, but can also be introduced during a manufacturing process such as a pulverization step or a nitriding step, and is inevitably mixed in the phosphor of the present embodiment. Alternatively, the halogen atom can be introduced not only as an impurity in the raw material metal but also during a manufacturing process such as a pulverization step or a nitriding step. In particular, when a halide is used as the flux, the halogen atom can be introduced into the phosphor. Halogen atoms tend to be included with high probability.

The phosphor of the present embodiment has a cubic crystal structure in its crystal structure and belongs to the F-43 m space group. Further, in the crystal structure, Li and Mg may be present at the same crystal site, and two or more types of Li / Mg sites having different occupancy rates of Li and Mg may be present. Then, N adjusts the electrically neutral condition.

The lattice constant a of the phosphor of the present embodiment is usually 4.486 Å or more, preferably 4.736 Å or more, more preferably 4.835 Å or more, and usually 5.483 Å or less, preferably 5.234 Å or less. It is preferably 5.134 Å or less. The same applies to the lattice constants b and c, where α = β = γ = 90 °.

The phosphor of the present embodiment preferably contains a crystal phase having a composition represented by the following formula [1] or [2].

_{M a Li 2-x Mg x} N y-z O z [1]
(In the above formula [1], a, x, y, and z are values that independently satisfy the following formula.
0 ≤ a ≤ 0.1
0 <x ≦ 1.25
0.67 ≤ y ≤ 1.1
0 ≦ z ≦ 0.1
0.67 ≤ yz ≤ 1.1)

_{M a Li 2-x Mg x} N y-z O z X b [2]
(In the above formula [2], a, b, x, y, and z are values that independently satisfy the following formula.
0 ≤ a ≤ 0.1
0 <x ≦ 1.25
0.67 ≤ y ≤ 1.1
0 ≦ z ≦ 0.1
0 ≦ b ≦ 0.01
0.67 ≤ yz ≤ 1.1)

In the above formula [2], the X element is one or more elements selected from the group consisting of calcium (Ca), strontium (Sr), and barium (Ba), and / or fluorine (F, element). Is. The X element preferably contains Sr or F, and more preferably Sr. The element X may be partially substituted with a divalent metal element other than the alkaline earth metal element, for example, zinc (Zn) or the like.

In the above formulas [1] and [2], a represents the content of M element, the range of which is usually 0 ≦ a ≦ 0.1, and the lower limit is preferably 0.0001, more preferably 0. It is .001, and its upper limit is preferably 0.05, more preferably 0.01.

In the above formulas [1] and [2], x represents the content of Mg (or the amount of substitution of Li and Mg), the range of which is usually 0 <x ≦ 1.25, and the lower limit is preferable. Is 0.5, more preferably 0.75, particularly preferably 0.875, and its upper limit is preferably 1.125, more preferably 1.05.

In the above formulas [1] and [2], z represents the content of O (the amount of replacement of O with N), the range of which is usually 0 ≦ z ≦ 0.1, and the upper limit is preferable. Is 0.09, more preferably 0.0625, still more preferably 0.05.

In the above formulas [1] and [2], yz represents the nitrogen content and takes a value that satisfies the electric neutrality condition in the crystal structure. The range is usually 0.67 ≦ y ≦ 1.1, the lower limit is preferably 0.83, more preferably 0.92, and the upper limit is preferably 1.04. It is preferably 1.02.

In the above formula [2], b represents the content of the X element, the range of which is usually 0 ≦ b ≦ 0.01, and the lower limit is preferably 0.0001, more preferably 0.001. Yes, and the upper limit thereof is preferably 0.08, more preferably 0.05.

If the content of any of these is within the above range, it is easy to obtain a phosphor having excellent light emission characteristics.

<Physical characteristics of phosphor>
[Emission color]
The emission color of the phosphor of the present embodiment can be excited by light in the near-ultraviolet region to short-wavelength visible region having a wavelength of 300 nm or more and 480 nm or less, and by adjusting the chemical composition or the like, green, yellowish green, yellow, A desired emission color such as red can be emitted.

[Emission spectrum]
The phosphor of the present embodiment preferably has the following characteristics when the emission spectrum when excited with light having a wavelength of 300 nm or more and 480 nm or less is measured. That is, the peak wavelength (maximum emission wavelength) in the above-mentioned emission spectrum is preferably in the range of 610 to 640 nm, and more preferably in the range of 615 to 635 nm. When the emission spectrum is within the above range, a good red color with a special color rendering index R9 is exhibited in a light emitting device using the obtained phosphor, which is preferable.

[Half width of emission spectrum]
In the phosphor of the present embodiment, the half width of the emission peak in the above emission spectrum is preferably in the range of 1 to 20 nm, more preferably 2 to 15 nm. Narrow-band red light emission within the above range is preferable because when used in a light emitting device such as a liquid crystal display device, a good red color having a special color rendering index R9 tends to be obtained and the color reproduction range tends to be widened.

The excitation light source for exciting the phosphor of the present embodiment is not particularly limited, but for example, a xenon lamp, a GaN-based LED, or the like can be used. Further, as the excitation light source, for example, an LED light emitting element that emits light having a wavelength in the near-ultraviolet ray or short wavelength visible region of 300 nm or more and 480 nm or less can be used. As the LED light emitting element, one made of a nitride semiconductor such as GaN or InGaN is known, and by adjusting the composition, it can be an excitation light source that emits light having a predetermined wavelength. For the measurement of the emission spectrum of the phosphor of the present embodiment and the calculation of the emission peak wavelength, peak relative intensity, peak half-value width, etc., for example, a 150 W xenon lamp is used as an excitation light source, and a multi-channel CCD is detected as a spectrum measurement device. This can be performed using a fluorescence measuring device (manufactured by JASCO Corporation) equipped with a device C7041 (manufactured by Hamamatsu Photonics Co., Ltd.). Further, for example, as the LED light emitting device, the phosphor of the present invention is used to manufacture the LED light emitting device by a known method as described in JP-A-5-152609, JP-A-7-99345, Patent Publication No. 2927279, and the like. Can be done.

[Excitation wavelength]
The phosphor of the present embodiment is usually excited to a wavelength range of 300 nm or more, preferably 315 nm or more, more preferably 330 nm or more, and usually 500 nm or less, preferably 470 nm or less, more preferably 450 nm or less, still more preferably 420 nm or less. It has a peak (absorption maximum wavelength). That is, the phosphor of the present embodiment can usually be excited by light in the near-ultraviolet or short wavelength visible region.

[Crystal system and space group]
The crystal system in the phosphor of the present embodiment is a cubic system (Cubic). Further, the space group in the phosphor of the present embodiment preferably belongs to No. 216 (F-43 m) based on "International Tables for Crystallography (Third, revised edition), Volume A SPACE-GROUP SYMMETRY". Here, the lattice constant and the space group of the phosphor can be obtained according to a conventional method. Specifically, the lattice constant can be obtained by Rietveld analysis of the results of X-ray diffraction and neutron diffraction, and the space group has an X-ray diffraction structure using electron beam diffraction or a single crystal. It can be obtained by analysis and neutron diffraction structure analysis.

<Manufacturing method of phosphor>
The method for producing the phosphor of the present embodiment is not particularly limited, but for example, a raw material for the M element, which is an activating element (hereinafter, may be appropriately referred to as “M source”), and a raw material for Li (hereinafter, referred to as “M source”). It may be appropriately referred to as "Li source"), a raw material for Mg (hereinafter, may be appropriately referred to as "Mg source"), and a raw material for element X to be blended as necessary (hereinafter, appropriately referred to as "Mg source"). A method including at least a step of mixing the phosphor raw materials (mixing step) such as "X source") and a step of firing the obtained mixture (firing step) is preferably used. In the following, for example, the raw material of the element Eu may be referred to as "Eu source", the raw material of the element Sr may be referred to as "Sr source", and the same shall apply to other elements. On the other hand, N and O can be supplied as nitrides and oxides of M source, Li source, Mg source, X source and the like, and can also be supplied as impurities contained in each raw material or impurities in the manufacturing process. Is.

[Fluorescent material]
Examples of phosphor raw materials such as M source, Li source, Mg source, and X source include silicates, oxides, carbonates, nitrides, nitrides, halides (chlorides, fluorides), and acid fluorides. , Hydroidides, oxalates, sulfates, nitrates, organic metal compounds, precursor compounds thereof and the like can be used, and the types thereof are not particularly limited. As the phosphor raw material, one type can be used alone, and two or more types can be used in any combination and ratio. Among these, oxides, nitrides, halides, carbonates and silicides are preferable, and oxides, nitrides and halides are more preferable.

If necessary, the phosphor of the present embodiment may be synthesized in advance and mixed with the raw material mixture as a seed crystal (seed crystal). By using the seed crystal in this way, crystallization and low temperature synthesis are promoted, and a phosphor having a higher crystallinity tends to be easily obtained. The blending ratio of the seed crystal is not particularly limited, but is preferably in the range of 0.1 to 30 parts by mass with respect to 100 parts by mass of the phosphor raw material.

(M source)
Among the M sources that are active elements, specific examples of the Eu source include Eu ₂ O ₃ , Eu ₂ (SO ₄ ) ₃ , Eu ₂ (C ₂ O ₄ ) ₃・ 10H ₂ O, EuF ₃ , EuCl _{2. , EuCl 3, Eu (nO 3} ) 3 · 6H 2 O, EuN, but EuNH like, not particularly limited thereto. Among these, Eu ₂ O ₃ , EuF ₃ , EuN and the like are preferable, and EuF ₃ or EuN is more preferable. On the other hand, as specific examples of raw materials for other active elements such as Sm source, Tm source, and Yb source, in each of the compounds mentioned as specific examples of Eu source, Eu is replaced with Sm, Tm, Yb, etc., respectively. Can be mentioned.

(Li source)
Specific examples of the Li source include Li ₂ O, LiOH, Li ₂ CO _{3 , Li NO 3} , Li ₂ SO ₄ , LiF, LiCl, Li ₃ N, _{Li NH 2,} and hydrates of these compounds. , These are not particularly limited. Among _{these, Li 2 O, Li 2 CO} 3, Li 3 N and is more preferably Li ₃ N. Further, from the viewpoint of luminous efficiency, those having high purity are preferable. On the other hand, when Li is partially replaced by another monovalent element, as a specific example of the raw material of the other monovalent element, in each compound mentioned as a specific example of the Li source, Li is Na. Examples thereof include compounds replaced with K, Rb, Cs and the like. As the Li source, a single Li may be used.

(Mg source)
Specific examples of the Mg _{source, MgO, Mg (OH) 2} , MgCO 3, Mg (NO 3) 2, MgSO 4, Mg (C 2 O 4) · H 2 O, Mg (OCOCH 3) 2 · 0. _{5H 2 O, MgF 2, MgCl} 2 and hydrates _thereof, Mg ₂ N, but _Mg 3 N 2, MgNH like, not particularly limited thereto. Among these, _MgO, preferably MgCO 3, _Mg 3 _{N 2,} and more preferably _Mg 3 _{N 2.} Further, from the viewpoint of reactivity, those having a small particle size and high purity from the viewpoint of luminous efficiency are preferable.

(X source)
Of X source, specific examples of Sr _{source, SrO, Sr (OH) 2} · 8H 2 O, SrCO 3, Sr (NO 3) 2, SrSO 4, Sr (C 2 O 4) · H 2 O, _{Sr (OCOCH 3) 2 · 0.5H} 2 O, SrF 2, SrCl 2, Sr 2 N, but _Sr 3 N 2, SrNH like, not particularly limited thereto. Among _{these, SrO, SrCO 3, Sr 2} N, preferably _Sr 3 _{N 2,} more preferably _Sr 3 _{N 2.} Further, from the viewpoint of reactivity, those having a small particle size and high purity from the viewpoint of luminous efficiency are preferable. On the other hand, specific examples of raw materials for other alkaline earth metal elements such as Ca source and Ba source include compounds in which Sr is replaced with Ca, Ba, etc. in each of the compounds mentioned as specific examples of the Sr source. ..

As the above-mentioned M source, Li source, Mg source and X source, only one type may be used, or two or more types may be used in any combination and ratio. In general, the above-mentioned fluorescent material raw materials are weighed so as to obtain a fluorescent material having a desired composition, sufficiently mixed using a ball mill or the like, filled in a rut, and fired at a predetermined temperature and atmosphere to obtain the obtained product. By pulverizing and washing the fired product, the phosphor of the present embodiment having a desired composition can be obtained.

[Mixing process]
The mixing method of the phosphor raw material may be performed by a known method such as a dry mixing method or a wet mixing method, and is not particularly limited. Examples of the dry mixing method include a mixing method using a ball mill or the like. As a wet mixing method, for example, a solvent such as hexane or a dispersion medium is added to the above-mentioned phosphor raw material and mixed using a ball mill, a mortar, a pestle, or the like to prepare a solution or a slurry. This is a method of drying by spray drying, heat drying, natural drying or the like. Examples of the solvent or dispersion medium include water, an organic solvent, a mixed solvent thereof, and the like, but the solvent is not particularly limited thereto. For example, ester solvents such as methyl acetate, ethyl acetate, propyl acetate and butyl acetate; ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone; alcohol solvents such as methyl alcohol, ethyl alcohol, isopropyl alcohol and n-butanol; Carbohydrate-based solvents such as hexane, cyclohexane, methylcyclohexane, and ethylcyclohexane; aromatic hydrocarbon-based solvents such as toluene and xylene; or mixed solvents thereof; and the like can be mentioned, but are not particularly limited thereto. Among these, alcohol-based solvents and hydrogenated hydrogen-based solvents are preferable. These can be used individually by 1 type or in combination of 2 or more types.

[Baking process]
The obtained mixture is filled in a heat-resistant container such as a crucible or a tray made of a material having low reactivity with each phosphor raw material. The material of the heat-resistant container used at the time of firing is not particularly limited as long as the effect of the present embodiment is not impaired, and examples thereof include a crucible such as boron nitride and a container made of molybdenum or tungsten.

The firing temperature during the firing step varies depending on the pressure, the external atmosphere, and the like, but is usually in the temperature range of 500 ° C. or higher and 2000 ° C. or lower. The maximum temperature reached in this firing step is usually 600 ° C. or higher, preferably 700 ° C. or higher, more preferably 800 ° C. or higher, and usually 2000 ° C. or lower, preferably 1800 ° C. or lower. If the calcination temperature is too high, some of the elements contained in the matrix are desorbed, many defects are generated in the crystal, and the obtained crystal tends to be colored. If the firing temperature is too low, the progress of the solid phase reaction tends to be slow. In some cases, it may be difficult to obtain a phosphor having a target phase as a main phase. Further, even if the desired crystal phase is obtained very slightly, if the firing temperature is too low, the element that is the center of light emission, for example, Eu element, may not be diffused in the crystal and the quantum efficiency may be lowered. Further, if the firing temperature is too high, the elements constituting the target phosphor crystal are likely to volatilize, lattice defects are likely to be formed, or the crystal phase may be decomposed and another phase may be generated as an impurity. ..

The pressure during the firing step varies depending on the firing temperature, the external atmosphere, and the like, but is usually 0.1 MPa or more, preferably 0.2 MPa or more, and usually 200 MPa or less, preferably 190 MPa or less.

The firing atmosphere in the firing step is arbitrary as long as the phosphor of the present embodiment can be obtained, but it is preferably an atmosphere containing an inert gas (nitrogen, argon, etc.). Specifically, a nitrogen gas atmosphere, a hydrogen-containing nitrogen atmosphere, and the like are preferable, and a nitrogen gas atmosphere is more preferable. The oxygen content of the firing atmosphere is not particularly limited, but is preferably 50 ppm or less, more preferably 20 ppm or less, and further preferably 10 ppm or less.

The firing time in the firing step varies depending on the temperature and pressure at the time of firing, the external atmosphere, and the like, but is usually 10 minutes or more, preferably 30 minutes or more, and usually 72 hours or less, preferably 24 hours or less. If the firing time is too short, grain formation and grain growth cannot be promoted, so that it tends to be difficult to obtain a phosphor having good characteristics, and if the firing time is too long, volatilization of constituent elements is promoted. Therefore, atomic defects tend to induce defects in the crystal structure, making it difficult to obtain a phosphor having good characteristics.

[Post-treatment process]
The obtained fired product (fluorescent material) is usually granular or lumpy. This can be combined with crushing, grinding and / or classification operations to produce a powder of the desired size. Specific examples thereof include a method of crushing the obtained fired product using a crusher such as a ball mill, a vibration mill, or a jet mill, a method of sieving the obtained fired product, and the like. Not limited. Further, if necessary, a step of washing the obtained fired product may be provided. After the washing step, it is preferable to dry the phosphor until the adsorbed or adsorbed water disappears. Further, if necessary, dispersion / classification treatment may be performed to disperse the agglomerates. The phosphor of the present embodiment may be formed by a so-called alloying method in which a constituent metal element is alloyed in advance and the constituent metal element is nitrided to form the phosphor.

The phosphor thus obtained preferably has a low content of impurities from the viewpoint of improving the light emitting characteristics. In particular, when a large amount of the above-mentioned X element (Ca, Sr, Ba, F) is contained, light emission tends to be inhibited. Therefore, the total content ratio of the X element is preferably 1500 ppm or less, more preferably 1500 ppm or less. It is 1200 ppm or less, more preferably 1000 ppm or less.

<Fluorescent compound-containing composition>
The phosphor of the present embodiment can be used as it is as a light emitting material, but it can also be mixed with other materials and used as a phosphor-containing composition. That is, the fluorescent substance-containing composition may contain a substance different from that of the fluorescent substance of the present embodiment. For example, when the phosphor of the present embodiment is used for a light emitting device or the like, it can be used in a form of being dispersed in a liquid medium, a binder resin, or a sealing resin. When used as a phosphor-containing composition, the content ratio of the phosphor of the present embodiment is preferably 20% by mass or more, more preferably 30% by mass or more, still more preferably 40% by mass or more, based on the total amount of the composition. be. At this time, any inorganic material and / or organic material can be used as the substance different from the phosphor of the present embodiment, for example, a phosphor different from the phosphor of the present embodiment; addition reaction. Binder resin and sealing resin such as type silicone or condensation reaction type silicone resin, modified silicone resin, polyimide silicone resin, polycarbonate resin, epoxy resin, polyvinyl resin, polyethylene resin, polypropylene resin, polyester resin; glass; Diffusing agents; thickeners; bulking agents; interfering agents and the like can be mentioned, but are not particularly limited thereto.

<Light emitting device, etc.>
The phosphor of the present embodiment described above and a phosphor-containing composition using the same are suitably used as a light emitting material for a light emitting device such as a lighting device or an image display device. This type of light emitting device comprises at least an excitation light source that emits near-ultraviolet or short wavelength visible light of 300 nm or more and 480 nm or less, and a phosphor that converts at least a part of the light emitted by the excitation light source into a different emission spectrum. As the phosphor, the phosphor of the present embodiment described above and a phosphor-containing composition using the same may be used. As light emitting devices such as lighting devices and image display devices, LED devices such as LED lighting devices and LED image display devices, EL devices such as EL lighting devices and EL image display devices, fluorescent lamps, and the like are known. More specifically, examples thereof include a white light emitting diode, a lighting fixture including a plurality of white light emitting diodes, a backlight for a liquid crystal panel, and the like, but the present invention is not particularly limited thereto. Examples of the image display device include a vacuum fluorescent display (VFD), a field emission display (FED), a plasma display panel (PDP), a cathode ray tube (CRT), a liquid crystal display (LCD), and the like, but the image display device is particularly limited to these. Not done. Various device configurations and embodiments of the light emitting device are known, and the configurations thereof are not limited at all, and known device configurations can be arbitrarily adopted. For example, those described in JP-A-2007-291352 can be mentioned. Examples of the light emitting device include a cannonball type, a cup type, a chip-on-board type, a remote phosphor, and the like. The image display device is not limited in specific configuration, but is preferably used together with a color filter. For example, when a color image display device using a color liquid crystal display element is configured as an image display device, the light emitting device is used as a backlight, an optical shutter using a liquid crystal display, and a color filter having red, green, and blue pixels. An image display device can be formed by combining with and.

As the excitation light source, a light source that emits light having an emission peak in the near-ultraviolet or short-wavelength visible region having a wavelength of 300 nm or more and 480 nm or less that matches the excitation peak (absorption maximum wavelength) of the phosphor of the present embodiment is preferably used. Examples of such a light source include a light emitting diode (LED), a laser diode (LD), a semiconductor laser, an organic EL light emitter (OLED), and the like. As a result, a desired emission color such as green, yellowish green, yellow, or red can be efficiently emitted from the phosphor.

Hereinafter, the content of the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples as long as the gist of the present invention is not exceeded. The values of various production conditions and evaluation results in the following examples have meanings as preferable values of the upper limit or the lower limit in the embodiment of the present invention, and the preferable range is the preferable value of the upper limit or the lower limit described above. The preferable range may be a range defined by a combination of the above-mentioned upper limit or lower limit value and the value of the following examples or the values of the examples.

<Measurement method>
[Light emission characteristics]
The luminescent particles were encapsulated in a glass capillary, and the excitation luminescence spectrum and the luminescence spectrum were measured using an Xe spectroscopic excitation device QE1100 (manufactured by Otsuka Electronics Co., Ltd.) and a luminescence detector MCPD-7700 (manufactured by Otsuka Electronics Co., Ltd.). The excitation spectrum is a measurement result when the emission at 627 nm is monitored, and the emission spectrum is excited at 358 nm. The emission peak wavelength and the half width of the emission peak were read from the obtained emission spectrum.

[Elemental analysis]
After selecting crystals by observation with a scanning electron microscope (SEM), each element was analyzed using an energy dispersive X-ray analyzer (EDX).

[Crystal structure analysis]
The X-ray diffraction data of the single crystal particles were measured by a single crystal X-ray diffractometer (Bruker AXS, D8 QUEST) equipped with an imaging plate and a graphite monochrome meter and using MoKα as an X-ray source. APEX2 was used for data collection and refinement of the lattice constant, and SADABS was used for X-ray shape absorption correction. Crystal structure parameters were refined using SHELXL-97 for the F ^{2 data.} In addition, VESTA was used for drawing the crystal structure.

(Example 1)
_{Li 3} N, Mg ₃ N ₂ , Sr ₃ N ₂ , and EuF ₃ were used as the phosphor raw material powder, and _{SrF 2} powder was used as the flux. These raw materials were _{weighed to Li 3} N 1.6684 g, Mg ₃ N ₂ 2.4647 g, Sr ₃ N ₂ 0.7784 g, EuF ₃ 0.0883 g, and SrF ₂ 0.2500 g, and then placed in a mortar. Mixing was performed until the mixture became uniform to obtain a raw material mixed powder of Example 1. 0.50 g of the obtained mixed raw material powder was separated and filled in a container made of molybdenum. All of these operations were performed in a glove box filled with high-purity nitrogen gas.
Next, the container was placed in a tube furnace, high-purity nitrogen gas was circulated, and then calcined at room temperature to 1000 ° C. for 12 hours. The calcined container was introduced into a glove box filled with high-purity nitrogen gas, and the obtained product was crushed in a mortar to obtain a calcined powder of Example 1.

A red particle-like phosphor was collected from the obtained calcined powder, sealed in a glass capillary, and crystal structure analysis was performed by single crystal X-ray diffraction measurement. As a result, the phosphor had a new crystal structure. Was confirmed. This phosphor belonged to the cubic system, belonged to the F-43m space group, and occupied the crystal parameters and atomic coordinates shown in Table 1. The crystal composition when Eu was not contained was Li ₁ Mg ₁ N ₁ . The seat occupancy rate in Table 1 is an example and is not limited to the ratio as described.

Furthermore, elemental analysis (EDX measurement) was performed on the phosphor of Example 1. The EDX measurement results are shown in Table 2. From the measurement results, it was confirmed that the red particles contained Mg and N as the main components. Li is not detected by EDX measurement. Then, Sr, O, and F detected as trace components are considered to be solid solution components in the crystal or impurities near the surface.

It is difficult to accurately evaluate the element ratio of cation and anion by EDX measurement, but when the ratio of Mg and N is interpreted as about 1: 1, the ratio of Li, Mg and N is about 1 due to the electrical neutrality condition. It is 1: 1 and does not contradict the structural analysis result.

Next, the results of measuring the emission / excitation spectra of the phosphor of Example 1 are shown in FIG. The phosphor of Example 1 showed a narrow band red emission having an emission peak wavelength of 627 nm and a half width of 4 nm, which was presumed to be due to ^{Eu 3+.} The excitation band of the phosphor of Example 1 has a peak of 358 nm and extends to around 480 nm (when standardized at 358 nm, the relative intensity at 400 nm is 0.82, and the relative intensity at 450 nm is 0.17), it can be seen that it is suitable for excitation with light in the near-ultraviolet or short wavelength visible region.

Since the phosphor of the present invention has a crystal structure and emission characteristics different from those of the conventional phosphor and emits red light by light in the near-ultraviolet or short wavelength visible region, the light emitting device, the lighting device and the image It can be widely and effectively used as a fluorescent material used in various applications such as display devices.

Claims (11)

Crystals having M element, Li, Mg, and N (provided that M element is at least one or more activating element selected from the group consisting of Eu, Ce, Pr, Sm, Tb, Dy, and Yb). A phosphor containing a phase
The crystal phase is a phosphor having a cubic space group having a crystal structure belonging to F-43 m and having a lattice constant satisfying the following range.
4.486 [Å] ≤ lattice constant a ≤ 5.483 [Å] The crystal phase further has O and is represented by the following formula [1].
The fluorescent substance according to claim 1.
_{M a Li 2-x Mg x} N y-z O z [1]
(In the above formula [1], a, x, y, and z are values that independently satisfy the following formula.
0 ≤ a ≤ 0.1
0 <x ≦ 1.25
0.67 ≤ y ≤ 1.1
0 ≦ z ≦ 0.1
0.67 ≤ yz ≤ 1.1) The crystal phase further has elements O and X (wherein element X is at least one element selected from the group consisting of Ca, Sr, and Ba and / or F) and has the following formula [ 2], characterized by being represented by
The fluorescent substance according to claim 1.
_{M a Li 2-x Mg x} N y-z O z X b [2]
(In the above formula [2], a, b, x, y, and z are values that independently satisfy the following formula.
0 ≤ a ≤ 0.1
0 <x ≦ 1.25
0.67 ≤ y ≤ 1.1
0 ≦ z ≦ 0.1
0 ≦ b ≦ 0.01
0.67 ≤ yz ≤ 1.1) The M element is characterized by containing Eu.
The fluorescent substance according to any one of claims 1 to 3. When irradiated with excitation light having a wavelength of 300 nm or more and 480 nm or less, it has an emission peak wavelength in the range of 610 to 640 nm, and the half width of the emission peak wavelength is 1 to 20 nm.
The fluorescent substance according to any one of claims 1 to 4. In the above formula, 0 <a ≦ 0.01 and 0 ≦ z ≦ 0.09.
The fluorescent substance according to any one of claims 2 to 5. The content ratio of the X element in terms of element amount is 1500 ppm or less in total.
The fluorescent substance according to any one of claims 3 to 6. The fluorescent substance according to any one of claims 1 to 7 is contained, and the fluorescent substance is contained in an amount of 20% by mass or more based on the total amount.
Fluorescent compound-containing composition. It is provided with at least an excitation light source that emits excitation light having a wavelength of 300 nm or more and 480 nm or less, and a phosphor that converts at least a part of the light emitted by the excitation light source into a different emission spectrum.
The fluorescent substance comprises at least the fluorescent substance according to any one of claims 1 to 7 and / or the fluorescent substance-containing composition according to claim 8.
Light emitting device. The light emitting device according to claim 9 is provided.
Lighting device. The light emitting device according to claim 9 is provided.
Image display device.

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