JP6531509B2 - Nitride phosphor, manufacturing method thereof and light emitting device - Google Patents

Description

  The present disclosure relates to a nitride phosphor, a method of manufacturing the same, and a light emitting device.

  By combining a light source and a wavelength conversion member capable of emitting light of a hue different from that of the light source by being excited by light from the light source, light emission capable of emitting light of various hues according to the principle of color mixture of light Devices are being developed. In particular, a light emitting device formed by combining a light emitting diode (Light Emitting Diode: hereinafter referred to as "LED") and a phosphor is actively applied to a lighting device, a backlight of a liquid crystal display device, etc. Is advancing. For example, in a light emitting device of white light emission, a liquid crystal display device is obtained by combining a phosphor emitting light at short wavelengths such as blue-green, green, yellow-green and the like and a phosphor emitting light at long wavelengths such as orange and red. It is possible to improve the color reproduction range of the above and the color rendering of the lighting device.

Phosphors based on inorganic crystals containing nitrogen in the crystal structure, such as sialon phosphors, oxynitride phosphors and nitride phosphors, have been proposed as phosphors with little reduction in luminance even at high energy excitation. . Among these, as an example of the nitride phosphor, a red phosphor activated with Eu ²⁺ as a host crystal (hereinafter referred to as "CASN phosphor") using CaAlSiN ₃ and a part of Ca of the CASN phosphor as Sr There are known substituted (Sr, Ca) AlSiN ₃ : Eu (hereinafter referred to as “SCASN phosphors”). The CASN phosphor and the SCASN phosphor have emission peak wavelengths in a wide range of 610 to 680 nm. Although the full width at half maximum of these emission spectra is relatively narrow at 75 to 95 nm, further improvement of the color reproduction range is desired when used as a light emitting device for liquid crystal display devices, and a phosphor with a narrower half width is desirable. It is rare.

In recent years, SrLiAl ₃ N ₄ : Eu (hereinafter referred to as “SLAN phosphor”) has been proposed as a new nitride phosphor having a narrow half width of 70 nm or less. The emission peak wavelength of this compound is around 650 nm (see, for example, Patent Document 1 and Non-Patent Document 1). This SLAN phosphor measures, for example, a raw material powder containing lithium aluminum hydride (LiAlH ₄ ), aluminum nitride (AlN) and europium fluoride (EuF ₃ ) at a stoichiometric ratio such that Eu = 0.4 mol%. After mixing, they are put into a tungsten crucible and manufactured by firing in a high frequency heating furnace at 1000 ° C. for 2 hours under atmospheric pressure of a mixed gas atmosphere of hydrogen and nitrogen.

International Publication No. 2013/175336

Nature Materials, NMAT4012, 2014

However, in the SLAN phosphor obtained by the above manufacturing method, there is room for improvement in the internal quantum efficiency, and a phosphor having more excellent luminous efficiency is desired.
Accordingly, an object of an embodiment according to the present disclosure is to provide a nitride phosphor excellent in light emission efficiency.

The specific means for solving the problems is as follows, and the present disclosure includes the following aspects.
The first embodiment has a composition represented by the following formula (I), is excited by light in the wavelength range of 400 nm to 570 nm, has an emission peak wavelength in the range of 630 nm to 670 nm, and has a reflectance of 650 nm. It is a nitride fluorescent material whose ratio to the reflectance at 460 nm is 2 or more.
M ^a _w M ^b _x Eu _y Al ₃ N _z (I)
Wherein, ^{M a} is, Ca, Sr, at least one element selected from the group consisting of Ba, and Mg, ^{M b} is Li, at least one element selected from the group consisting of Na and K W, x, y and z are respectively 0.8 ≦ w <1.0, 0.5 ≦ x <1.0, 0.001 <y ≦ 0.1, z = (2/3) w + (1/3) x + (2/3) y + 3 is satisfied.

The second embodiment is a method for producing a nitride phosphor having a composition represented by the following formula (I), wherein the raw material mixture is heated at a temperature of 1000 ° C. or more and 1300 ° C. or less and a pressure of 0.2 MPa or more and 200 MPa or less It is a manufacturing method of nitride fluorescent substance including processing in the atmosphere containing nitrogen gas.
M ^a _w M ^b _x Eu _y Al ₃ N _z (I)
Wherein, ^{M a} is, Ca, Sr, at least one element selected from the group consisting of Ba, and Mg, ^{M b} is Li, at least one element selected from the group consisting of Na and K W, x, y and z are respectively 0.8 ≦ w <1.0, 0.5 ≦ x <1.0, 0.001 <y ≦ 0.1, z = (2/3) w + (1/3) x + (2/3) y + 3 is satisfied.

  According to an embodiment of the present disclosure, a nitride phosphor excellent in luminous efficiency can be provided.

It is a schematic sectional drawing which shows an example of the light-emitting device which concerns on this embodiment. It is a X-ray-diffraction pattern of the nitride fluorescent substance which concerns on the comparative example 1 and Example 1 and 2. FIG. It is an emission spectrum which shows the relative emission intensity with respect to a wavelength about the nitride fluorescent substance which concerns on Comparative example 1 and 2 and Example 1, 2 and 3. FIG. It is a reflection spectrum which shows the reflectance with respect to a wavelength about the nitride fluorescent substance which concerns on Comparative example 1 and 2 and Example 1, 2 and 3. FIG. It is an example of the SEM image of the nitride fluorescent substance which concerns on the comparative example 1. FIG. It is an example of the SEM image of the nitride fluorescent substance which concerns on the comparative example 2. FIG. 5 is an example of a SEM image of a nitride phosphor according to Example 1; FIG. 16 is an example of a SEM image of a nitride phosphor according to Example 2. FIG. It is a luminescence spectrum which shows relative luminescence intensity to a wavelength about a luminescence device concerning Example A and comparative example A. It is a luminescence spectrum which shows relative luminescence intensity to a wavelength about a luminescence device concerning Example B and comparative example B.

  Hereinafter, a nitride phosphor according to the present disclosure, a method for manufacturing the same, and a light emitting device will be described based on the embodiments and examples. However, the embodiment shown below exemplifies a nitride phosphor and the like for embodying the technical concept of the present invention, and the present invention specifies the nitride phosphor and the like as follows. do not do. The relationship between the color name and the chromaticity coordinates, the relationship between the wavelength range of light and the color name of monochromatic light, etc. conform to JIS Z8110. The content of each component in the composition means the total amount of the plurality of substances present in the composition unless a plurality of substances corresponding to each component are present in the composition.

(Nitride phosphor)
The nitride phosphor according to the present embodiment has a composition represented by the following formula (I), is excited by light in the wavelength range of 400 nm to 570 nm, and has an emission peak wavelength in the range of 630 nm to 670 nm, The ratio of the reflectance at 650 nm to the reflectance at 460 nm is 2 or more.
M ^a _w M ^b _x Eu _y Al ₃ N _z (I)
Wherein, ^{M a} is, Ca, Sr, at least one element selected from the group consisting of Ba, and Mg, ^{M b} is Li, at least one element selected from the group consisting of Na and K W, x, y and z are respectively 0.8 ≦ w <1.0, 0.5 ≦ x <1.0, 0.001 <y ≦ 0.1, z = (2/3) w + (1/3) x + (2/3) y + 3 is satisfied.

When the reflectance ratio (R ⁶⁵⁰ / R ⁴⁶⁰ ) of the reflectance (R ⁶⁵⁰ ) at ⁶⁵⁰ nm to the reflectance (R ⁴⁶⁰ ) at ⁴⁶⁰ nm is 2 or more, excellent luminous efficiency can be achieved. The reflectance ratio is preferably 2.2 or more, and more preferably 2.5 or more. The upper limit of the reflectance ratio is not particularly limited, and is, for example, 10 or less, preferably 9 or less.

  The reflectance of the nitride phosphor at 460 nm is not particularly limited as long as the reflectance ratio is satisfied, and is, for example, 35% or less, preferably 30% or less. The lower limit of the reflectance at 460 nm is not particularly limited, and is, for example, 5% or more, preferably 10% or more. The reflectance at 650 nm is, for example, 60% or more, preferably 65% or more. The upper limit of the reflectance at 650 nm is not particularly limited, and is, for example, 100% or less, preferably 95% or less.

Nitride phosphor has an average reflectance at 470nm or less the wavelength range of 450nm average reflectance at 660nm or less the wavelength range of ^{640nm (R 640-660) (R 450-470} ) average reflectance ratio ^{(R 640- 660} / ^R450-470 ) is preferably 2 or more, more preferably 2.2 or more, and still more preferably 2.5 or more. The upper limit of the average reflectance ratio is not particularly limited, and is, for example, 10 or less, preferably 9 or less. When the average reflectance ratio is in the above range, it tends to be possible to achieve better light emission efficiency.

  The average reflectance in a wavelength range of 450 nm to 470 nm of the nitride phosphor is, for example, 35% or less, and preferably 30% or less. The lower limit of the average reflectance in the wavelength range of 450 nm to 470 nm is not particularly limited, and is, for example, 5% or more, preferably 10% or more. The average reflectance in the wavelength range of 640 nm to 660 nm is, for example, 60% or more, and preferably 65% or more. The upper limit of the average reflectance in the wavelength range of 640 nm to 660 nm is not particularly limited, and is, for example, 100% or less, preferably 95% or less.

  Here, the average reflectance is calculated as an arithmetic average value of the measured reflectances by measuring the reflectance at each wavelength at an interval of 1 nm including both ends of the wavelength range for which the average value is calculated.

In formula (I), M ^a preferably contains at least one of Ca and Sr from the viewpoint of light emission intensity. When M ^a contains at least one of Ca and Sr, the total molar ratio of Ca and Sr contained in M ^a is, for example, 85 mol% or more, preferably 90 mol%.
M ^b preferably contains at least Li from the viewpoint of the crystal structure stability. When M ^b contains Li, the molar ratio of Li contained in M ^b is, for example, 80 mol% or more, preferably 90 mol%.

  In the formula (I), x, y, z and w are not particularly limited as long as the above relation is satisfied. Among them, x is preferably 0.7 or more and less than 1.0, and more preferably 0.8 or more and less than 1.0, from the viewpoint of crystal structure stability. Moreover, y is Eu activation amount, and may be appropriately selected so as to achieve desired characteristics. For example, y preferably satisfies 0.002 ≦ y ≦ 0.020, and more preferably 0.005 ≦ y ≦ 0.015.

The nitride phosphor absorbs light in a wavelength range of 400 nm to 570 nm, which is a short wavelength side region of ultraviolet light to visible light, and emits fluorescence having a light emission peak wavelength of 630 nm to 670 nm. By using the excitation light source of the said wavelength range, a high fluorescent substance of luminous efficiency can be provided. In particular, it is preferable to use an excitation light source having a main emission peak wavelength at 420 nm or more and 500 nm or less, and more preferable to use an excitation light source having a main emission peak wavelength at 420 nm or more and 460 nm or less.
The emission spectrum of the nitride phosphor has an emission peak wavelength in the range of 630 nm to 670 nm, and preferably in the range of 640 nm to 660 nm. The half width of the emission spectrum is, for example, 65 nm or less, preferably 60 nm or less. The lower limit of the half width is not particularly limited, and is, for example, 45 nm or more.

In the nitride phosphor, europium (Eu), which is a rare earth, is a luminescent center. However, the luminescent center in the present embodiment is not limited to only europium, and a part of which is replaced with another rare earth metal or alkaline earth metal and coactivated with Eu can also be used. Eu ^2+, which is a divalent rare earth ion, is stably present when an appropriate ^host is selected, and exhibits an effect of emitting light.

The average particle diameter of the nitride phosphor is not particularly limited, and can be appropriately selected according to the purpose and the like. The average particle diameter of the nitride phosphor is, for example, 4.0 μm or more, preferably 4.5 μm or more, and more preferably 5.0 μm or more from the viewpoint of luminous efficiency. The average particle size is, for example, 20 μm or less, preferably 18 μm or less.
As the average particle size is larger, the absorptivity of excitation light and the luminous efficiency tend to be higher. As described above, the luminous efficiency of the light emitting device is further improved by incorporating the nitride phosphor excellent in optical characteristics into the light emitting device described later.
Moreover, it is preferable that the nitride fluorescent substance contains the fluorescent substance particle which has said average particle diameter value with high frequency. That is, the particle size distribution is preferably distributed in a narrow range. By using a phosphor having a small variation in particle size distribution, color unevenness is further suppressed, and a light emitting device having a better color tone can be obtained.

In the present specification, the average particle diameter of the nitride phosphor and the other phosphors is a numerical value called Fisher Sub Sieve Sizer's No., which is measured using an air transmission method. Be done. Specifically, after taking a sample of 1 cm ³ min at an ambient temperature of 25 ° C and humidity of 70%, packing it into a special tubular container, flowing dry air at a constant pressure, reading the specific surface area from the differential pressure And the average particle diameter.

  The nitride phosphor preferably has a structure with high crystallinity at least in part. For example, since the glass body (amorphous) has irregular structure and low crystallinity, the component ratio in the phosphor is not constant unless the reaction conditions in the production process can be controlled so as to be strictly uniform. And chromaticity unevenness tend to occur. On the other hand, the nitride phosphor according to the present embodiment tends to be easily manufactured and processed because it is a powder or particles having a structure with high crystallinity at least in part. In addition, since the nitride phosphor can be easily dispersed uniformly in the organic medium, it is possible to easily prepare a luminescent plastic, a polymer thin film material, and the like. Specifically, the nitride phosphor has a structure in which, for example, 50% by weight or more, more preferably 80% by weight or more has crystallinity. This indicates the proportion of the crystal phase having a light-emitting property, and it is preferable to have 50% by weight or more of the crystal phase because light emission which can withstand practical use can be obtained. Therefore, the more crystalline phases, the better the light emission efficiency. This makes it possible to increase the light emission luminance and facilitate processing.

(Manufacturing method of nitride phosphor)
The production method of the present embodiment is a production method of a nitride phosphor having a composition represented by the following formula (I), and the raw material mixture is subjected to a temperature of 1000 ° C. to 1300 ° C., a pressure of 0.2 MPa to 200 MPa It is a manufacturing method of the nitride fluorescent substance including processing in the atmosphere containing the following nitrogen gas.
M ^a _w M ^b _x Eu _y Al ₃ N _z (I)
Wherein, ^{M a} is, Ca, Sr, at least one element selected from the group consisting of Ba, and Mg, ^{M b} is Li, at least one element selected from the group consisting of Na and K W, x, y and z are respectively 0.8 ≦ w <1.0, 0.5 ≦ x <1.0, 0.001 <y ≦ 0.1, z = (2/3) w + (1/3) x + (2/3) y + 3 is satisfied.

By heat-treating the raw material mixture at a predetermined temperature in a pressurized atmosphere containing nitrogen gas, a nitride phosphor having a desired composition and excellent in luminous efficiency can be efficiently produced. In addition, the nitride phosphor manufactured tends to have a reflectance ratio (R ⁶⁵⁰ / R ⁴⁶⁰ ) to a reflectance at 460 nm of reflectance at 650 nm of 2 or more, and an average reflectance ratio (R ^640-660 / R ^450-470 ) tends to be 2 or more, and better light emission efficiency can be achieved. Furthermore, nitride phosphors having an average particle size of 4.0 μm or more can be easily and efficiently produced.
The manufacturing method of the present embodiment can be applied to the manufacturing method of the nitride phosphor according to the present embodiment described above. That is, the nitride fluorescent substance manufactured by the manufacturing method of this embodiment can comprise the aspect of the said nitride fluorescent substance.

The raw material mixture used for the manufacturing method of nitride fluorescent substance will not be restrict | limited in particular, if the composition shown by Formula (I) can be achieved. The raw material mixture can include, for example, at least one selected from the group consisting of a single element of the metal element constituting the composition represented by the formula (I) and a metal compound thereof. Examples of the metal compound include hydrides, nitrides, fluorides, oxides, carbonates, chlorides and the like, and are selected from the group consisting of hydrides, nitrides and fluorides from the viewpoint of light emission characteristics. Preferably, it is at least one of When the raw material mixture contains an oxide, a carbonate, a chloride and the like as the metal compound, the content thereof is preferably 5% by mass or less and more preferably 1% by mass or less in the raw material mixture.
Above all, the raw material mixture is a metal compound containing a metal element selected from the group consisting of Ca, Sr, Ba and Mg, a metal compound containing a metal element selected from the group consisting of Li, Na and K, a metal compound containing Al And at least one metal compound selected from the group consisting of metal compounds containing Eu.

Specific examples of the metal compound containing a metal element selected from the group consisting of Ca, Sr, Ba and Mg (hereinafter also referred to as “first metal compound”) include SrN ₂ , SrN, Sr ₃ N ₂ , SrH ₂ , SrF ₂ , Ca ₃ N ₂ , CaH ₂ , CaF _{2 and the} like, and at least one selected from the group consisting of these is preferable.
The first metal compound preferably contains at least one of Ca and Sr. When the first metal compound contains Sr, a part of Sr may be substituted by Ca, Mg, Ba or the like. When the first metal compound contains Ca, a part of Ca may be substituted by Sr, Mg, Ba or the like. Thereby, the emission peak wavelength of the nitride phosphor can be adjusted. When the first metal compound contains Ca, it may further contain Li, Na, K, B, Al and the like.
The first metal compound is preferably used singly, but compounds such as imide compounds and amide compounds can also be used. The first metal compound may be used alone or in combination of two or more.

The metal compound containing a metal element selected from the group consisting of Li, Na and K (hereinafter also referred to as “second metal compound”) preferably contains at least Li, and at least a nitride of Li and a hydride thereof. It is more preferable that it is 1 type. When the second metal compound contains Li, part of Li may be substituted with Na, K or the like, and may contain another metal element constituting the nitride phosphor.
Specific examples of the second metal compound containing Li include Li ₃ N, LiN ₃ , LiH, LiAlH _{4 and the} like, and at least one selected from the group consisting of these is preferable.
The second metal compounds may be used alone or in combination of two or more.

The metal compound containing Al (hereinafter, also referred to as “third metal compound”) may be a metal compound substantially containing only Al as a metal element, and a part of Al is a Group III element Ga and It may be a metal compound substituted with a metal element selected from the group consisting of In and V, Cr, Co, etc., and contains, in addition to Al, other metal elements constituting a nitride phosphor such as Li. It may be a metal compound.
Specific examples of the third metal compound include AlN, AlH ₃ , AlF ₃ , LiAlH _{4 and the} like, and at least one selected from the group consisting of these is preferable.
The third metal compound may be used alone or in combination of two or more.

A metal compound containing Eu (hereinafter also referred to as “fourth metal compound”) contains Eu as an activator, but part of Eu is Sc, Y, La, Ce, Pr, Nd, Sm, Gd, It may be substituted by Tb, Dy, Ho, Er, Tm, Yb, Lu and the like. By replacing part of Eu with another element, it is considered that the other element acts as a co-activator, for example. The color tone can be changed by co-activating the nitride phosphor, and the light emission characteristics can be adjusted. When a mixture containing Eu is used as a nitride phosphor, the blending ratio can be changed as desired. Although europium mainly has divalent and trivalent energy levels, the nitride phosphor of the present embodiment uses at least Eu ²⁺ as an activator.

Specific examples of the fourth metal compound include Eu ₂ O ₃ , EuN, EuF _{3 and the} like, and at least one selected from the group consisting of these is preferable. The nitride phosphor according to the present embodiment includes divalent Eu as a light emission center, but divalent Eu is easily oxidized, and a raw material mixture may be formed using a metal compound containing trivalent Eu. it can.

  The raw material mixture may contain, in addition to the metal element alone and the metal compound, other metal elements other than those as needed. Other metal elements can usually constitute the raw material mixture as oxides, hydroxides, etc., but are not limited to these, and simple metals, nitrides, imides, amides, other inorganic salts, etc. It may be in the state of being contained in the above-mentioned starting material compound.

In addition, the nitride phosphor according to the present embodiment may contain a small amount of oxygen in its composition. As the origin of oxygen, various oxides as raw material compounds; trace oxides contained in nitrides, metals, etc .; oxides formed by oxidation of raw material compounds during heat treatment; adhesion to nitrided phosphor after formation Etc.
In general, it is possible to change the crystal structure of the phosphor and shift the emission peak wavelength of the phosphor by controlling the molar ratio of oxygen in the nitride phosphor composition. However, from the viewpoint of luminous efficiency, it is preferable that the amount of oxygen contained in the nitride phosphor be small. When the nitride phosphor contains an oxygen atom, the content is, for example, 6% by mass or less.

The raw material mixture may contain a flux such as a halide. When the raw material mixture contains a flux, the reaction between the raw materials is further promoted, and furthermore, the solid phase reaction proceeds more uniformly, so that the particle size is large, and a phosphor excellent in light emission characteristics can be obtained. This is considered to be because, for example, the heat treatment in the manufacturing method is performed at 1000 ° C. or more and 1300 ° C. or less, and this temperature is almost the same as the formation temperature of liquid phase such as halide which is a flux. As the halide, rare earth metals, alkaline earth metals, chlorides of alkali metals, fluorides and the like can be used. As the flux, the element ratio of the cation may be added as a compound to achieve the target composition, or it may be added in the form of adding each raw material to the target composition.
When the raw material mixture contains a flux, its content in the raw material mixture is, for example, 10% by mass or less, and preferably 5% by mass or less. Moreover, the content is 2 mass% or more, for example.

Next, among the nitride phosphors having the composition represented by the formula (I), the method for producing Sr _0.993 Eu _0.007 LiAl ₃ N ₄ as a design composition will be specifically described. The manufacturing method of is not limited to this.

Powders of SrN _x (equivalent to x = 2/3), Li ₃ N, AlN, and EuF ₃ are used as metal compounds constituting the raw material mixture, and these powders are used as Sr: Eu: Li: Al = 0.993: 0. The raw material mixture is obtained by weighing and mixing in an inert atmosphere glove box so as to be 007: 1.17: 3. Here, since Li is easily scattered at the time of firing, it is blended more than the theoretical value. Note that the present embodiment is not limited to this composition ratio.

The above raw material mixture is heat treated in a nitrogen atmosphere. The heat treatment can use, for example, a gas pressurized electric furnace. The heat treatment temperature can be in the range of 1000 ° C. or more and 1400 ° C. or less, preferably 1000 ° C. or more and 1300 ° C. or less, and more preferably 1100 ° C. or more and 1300 ° C. or less. The heat treatment uses two-step firing (multi-step firing) in which the first heat treatment is performed at 800 ° C. to 1000 ° C., the temperature is gradually increased, and the second heat treatment is performed at 1000 ° C. to 1400 ° C. You can also For the heat treatment of the raw material mixture, a carbon material such as graphite, boron nitride (BN) material, alumina (Al ₂ O ₃ ), crucible made of W, Mo material or the like, a boat or the like can be used.

The heat treatment atmosphere may be an atmosphere containing nitrogen gas, and may be an atmosphere containing at least one selected from the group consisting of hydrogen, argon, carbon dioxide, carbon monoxide, ammonia, etc. in addition to nitrogen gas. . 70 volume% or more is preferable and, as for the ratio of the nitrogen gas in heat processing atmosphere, 80 volume% or more is more preferable.
The heat treatment is performed in a pressurized atmosphere of 0.2 MPa or more and 200 MPa or less. The target nitride phosphors are more easily decomposed as the temperature is higher, but the decomposition can be suppressed by using a pressurized atmosphere, and more excellent light emission characteristics can be achieved. As a pressurization atmosphere, 0.2 MPa or more and 1.0 MPa or less are preferable as gauge pressure, and 0.8 MPa or more and 1.0 MPa or less are more preferable.

  The heat treatment time may be appropriately selected according to the heat treatment temperature, gas pressure and the like. The heat treatment time is, for example, 1 to 10 hours, preferably 2 to 4 hours.

By the above heat treatment, a phosphor represented by Sr _0.993 Eu _0.007 LiAl ₃ N ₄ can be obtained. However, the composition of this nitride phosphor is a theoretical composition estimated from the compounding ratio of the raw material mixture, and the coefficient of each element and the component such as F that scatters are excluded from the description. When the composition of the preparation is Al = 3, Sr, Eu, and Li are theoretical because the composition actually synthesized contains oxygen components derived from the raw materials etc. and decomposition and scattering occur during heat treatment. It may be less. In addition, the composition of the target nitride phosphor can be changed by changing the blending ratio of each raw material.

  Other manufacturing methods than the above are also possible. Specifically, a nitride phosphor may be produced by forming a raw material mixture using a hydride as a part of the above raw materials, or a single metal of each element was weighed to have a predetermined composition ratio. After the alloy is formed by melting later, the alloy is crushed, and the alloy is nitrided in a nitrogen gas atmosphere by a gas pressure sintering furnace, a HIP furnace or the like to produce a nitride phosphor having a target composition. It is also good.

  By the above manufacturing method, it is possible to obtain the target nitride phosphor. Eu is a rare earth element, and part of Eu may be replaced with various rare earth elements, and in addition to Eu, rare earth elements such as La, Ce, Gd, Tb, Dy, Ho, Er, Tm, Lu and the like It is also possible to use a nitride phosphor containing As described above, a desired nitride phosphor can be obtained.

  Although specific examples of data of light emission characteristics of the nitride phosphor according to the present embodiment will be described later, the nitride phosphor according to the present embodiment aims at a specific composition while adopting specific synthesis conditions. It was confirmed that better emission characteristics could be achieved.

(Light-emitting device)
Next, a light emitting device using the above nitride phosphor as a component of the wavelength conversion member will be described. The light emitting device of the present embodiment includes the first phosphor including the nitride phosphor, and an excitation light source that emits light in a wavelength range of 400 nm to 570 nm.

  A light emitting element can be used as the excitation light source. The light emitting element emits light in a wavelength range of 400 nm to 570 nm. The emission peak wavelength of the light emitting element is preferably in the wavelength range of 420 nm to 460 nm. By using a light emitting element having a light emission peak wavelength in this range as an excitation light source, it becomes possible to configure a light emitting device that emits mixed color light of light from the light emitting element and fluorescence from the fluorescent substance. Further, since the light emitted from the light emitting element to the outside can be effectively used, the loss of light emitted from the light emitting device can be reduced, and a highly efficient light emitting device can be obtained.

The half width of the emission spectrum of the light emitting element is not particularly limited. The half width can be, for example, 30 nm or less.
It is preferable to use a semiconductor light emitting element as the light emitting element. By using a semiconductor light emitting element as a light source, it is possible to obtain a stable light emitting device with high efficiency, high output linearity with respect to input, and resistance to mechanical shock.
The semiconductor as the light emitting element, for example, nitride semiconductor _{(In X Al Y Ga 1-} X-Y N, 0 ≦ X, 0 ≦ Y, X + Y ≦ 1) blue was used, the semiconductor light emitting element that emits green light, etc. Can be used.

  The first phosphor included in the light emitting device includes the above-described nitride phosphor. The nitride phosphor has a composition represented by the formula (I), is excited by light in a wavelength range of 400 nm to 570 nm, has an emission peak wavelength of 630 nm to 670 nm, and has a reflectance of 650 nm. The reflectance ratio to the reflectance at 460 nm is 2 or more. The details of the nitride phosphor are as described above, and preferred embodiments are also the same. The first phosphor is a red-emitting phosphor containing at least one of the aforementioned nitride phosphors.

The first phosphor can be contained in, for example, a sealing resin covering the excitation light source to constitute a light emitting device. In the light emitting device in which the excitation light source is covered with the sealing resin containing the first phosphor, part of the light emitted from the excitation light source is absorbed by the first phosphor and emitted as red light. The emitted light can be used more effectively by using an excitation light source which emits light in a wavelength range of 400 nm to 570 nm. Therefore, the loss of light emitted from the light emitting device can be reduced, and a highly efficient light emitting device can be provided.
The content of the first phosphor contained in the light emitting device is not particularly limited, and can be appropriately selected according to the excitation light source and the like. For example, the content of the first phosphor can be 1 to 50 parts by mass with respect to 100 parts by mass of the sealing resin, and is preferably 2 to 30 parts by mass.

  The light emitting device may include a second phosphor whose emission peak wavelength is different from that of the first phosphor. For example, by using a light emitting element that emits blue light and a first phosphor and a second phosphor excited by the light emitting device, white light excellent in color reproduction range and color rendering property is obtained. Can.

Examples of the second phosphor include a phosphor having a composition represented by any of the following formulas (IIa) to (IIh), and a composition represented by a formula selected from the group consisting of It is preferable to include at least one kind of phosphor having, and more preferably to contain at least one kind of phosphor having the composition represented by the formula (IIc) or (IIe).
(Y, Gd, Tb, Lu) ₃ (Al, Ga) ₅ O ₁₂ : Ce (IIa)
_{(Ba, Sr, Ca) 2} SiO 4: Eu (IIb)
Si _6-p Al _p O _p N 8- _p : Eu (0 <p ≦ 4.2) (II c)
_{(Ca, Sr) 8 MgSi 4} O 16 (Cl, F, Br) 2: Eu (IId)
_{(Ba, Sr, Ca) Ga} 2 S 4: Eu (IIe)
_{(Ba, Sr, Ca) 2} Si 5 N 8: Eu (IIf)
(Sr, Ca) AlSiN ₃ : Eu (IIg)
K ₂ (Si, Ge, Ti) F ₆ : Mn ( _II h)
In the composition formula (IIc), p preferably satisfies 0.01 <p <2.
The light emitting device may contain the second phosphor singly or in combination of two or more.

  The average particle size of the second phosphor is not particularly limited, and can be appropriately selected according to the purpose and the like. The average particle diameter of the second phosphor is preferably 2 μm or more and 35 μm or less, and more preferably 5 μm or more and 30 μm or less from the viewpoint of luminous efficiency.

  The content of the second phosphor can be appropriately selected according to the purpose and the like. For example, the content of the second phosphor can be 1 to 200 parts by weight with respect to 100 parts by weight of the sealing resin, and is preferably 2 to 180 parts by weight.

  The content ratio of the first phosphor and the second phosphor is not particularly limited as long as desired emission characteristics can be obtained, and can be appropriately selected according to the purpose and the like. For example, the content ratio of the first phosphor to the second phosphor (first phosphor / second phosphor) can be 0.01 to 5 on a weight basis, and 0.05 to 3 is preferable.

It is preferable that the first phosphor and the second phosphor (hereinafter, also simply referred to as “phosphors”) constitute a sealing material that covers the light emitting element together with the sealing resin. As a sealing resin which comprises sealing material, thermosetting resins, such as an epoxy resin, a silicone resin, an epoxy modified silicone resin, a modified silicone resin, can be mentioned.
The total content of the phosphors in the sealing material is not particularly limited, and can be appropriately selected according to the purpose and the like. The total content of the phosphor can be, for example, 5 to 300 parts by mass, preferably 10 to 250 parts by mass, and more preferably 15 to 230 parts by mass, with respect to 100 parts by mass of the sealing resin. Parts by weight are more preferred. When the content of the phosphor in the sealing material is in the above range, the light emitting element can be sufficiently covered, and the light emitted from the light emitting element can be efficiently wavelength-converted by the phosphor, and more efficiently It can emit light.

The sealing material may further include a filler, a light diffusing material, etc. in addition to the sealing resin and the phosphor. Examples of the filler include silica, titanium oxide, zinc oxide, zirconium oxide, alumina and the like.
When a sealing material contains a filler, the content can be suitably selected according to the objective etc. The content of the filler can be, for example, 1 to 20 parts by mass with respect to 100 parts by mass of the sealing resin.

  The type of the light emitting device is not particularly limited, and can be appropriately selected from commonly used types. Examples of the type of the light emitting device include a shell type and a surface mounting type. In general, the shell type refers to one in which the shape of the resin constituting the outer surface is formed into a shell type. Further, the surface mount type refers to one formed by filling a concave storage portion with a light emitting element serving as a light source and a resin. Further, as a type of light emitting device, a light emitting device as a light source is mounted on a flat mounting substrate, and a sealing resin containing a phosphor is formed in a lens shape or the like so as to cover the light emitting device. Can also be mentioned.

  An example of a light emitting device according to the present embodiment will be described based on the drawings. FIG. 1 is a schematic cross-sectional view showing an example of a light emitting device according to the present embodiment. This light emitting device is an example of a surface mounted light emitting device.

  The light emitting device 100 includes a package 40 having a recess, a light emitting element 10, and a sealing member 50 that covers the light emitting element 10. The light emitting element 10 is disposed in a recess formed in the package 40, and is electrically connected to a pair of positive and negative lead electrodes 20 and 30 disposed in the package 40 by a conductive wire 60. The sealing member 50 is filled in the recess and covers the light emitting element 10. The sealing member 50 further contains, for example, a sealing resin that is a thermosetting resin, and a first phosphor 71 and a second phosphor 72 that convert the wavelength of light from the light emitting element 10. A portion of the positive and negative lead electrodes 20 and 30 is exposed to the outer surface of the package 40. The light emitting device 100 emits light by receiving power supply from the outside through the lead electrodes 20 and 30.

  The sealing member 50 is formed by being filled with a translucent resin or glass so as to cover the light emitting element 10 placed in the recess of the light emitting device 100. In consideration of the ease of manufacture, the material of the sealing member is preferably a translucent resin. It is preferable to use a silicone resin composition as the translucent resin, but an insulating resin composition such as an epoxy resin composition or an acrylic resin composition can also be used. Moreover, although the 1st fluorescent substance 71 and the 2nd fluorescent substance 72 are contained in the sealing member 50, another material can also be added suitably further. For example, by including a light diffusing material, directivity from the light emitting element can be relaxed and a viewing angle can be increased.

  The sealing member 50 not only functions as a member for protecting the light emitting element 10, the first phosphor 71 and the second phosphor 72 from the external environment, but also functions as a wavelength conversion member. In FIG. 1, the first phosphor 71 and the first phosphor 72 are partially localized in the sealing member 50. By arranging the first fluorescent substance 71 and the first fluorescent substance 72 close to the light emitting element 10 in this manner, the wavelength of light from the light emitting element 10 can be efficiently converted, and the light emission efficiency is excellent. It can be a light emitting device. The arrangement of the light emitting element 10 and the sealing member 50 including the first fluorescent substance 71 and the first fluorescent substance 72 is not limited to the form in which they are arranged in close proximity to each other, and the first fluorescent substance In consideration of the influence of heat on the body 71 and the first phosphor 72, the light emitting element 10, the first phosphor 71, and the first phosphor 72 are spaced apart from each other in the sealing member 50. You can also In addition, by mixing the first phosphor 71 and the first phosphor 72 in the entire sealing member 50 at a substantially uniform ratio, it is possible to obtain light in which color unevenness is further suppressed.

  Examples of applications of the light emitting device include, but are not limited to, lighting devices, backlights of liquid crystal displays, display devices such as radars, and the like.

  Hereinafter, the present disclosure will be specifically described by way of examples, but the present disclosure is not limited to these examples.

Example 1
As a phosphor having a composition represented by M ^a _w M ^b _x E u _y Al ₃ N _z , M ^a = Sr, M ^b = Li, SrN _x (corresponding to x = 2/3), LiAlH ₄ , AlN, Glove of inert atmosphere such that EuF ₃ is used as each raw material, and the molar ratio as the charged amount ratio is Sr: Li: Eu: Al = 0.993: 1.1: 0.007: 3 The raw material mixture was obtained by weighing and mixing in a box. Here, since Li is easily scattered at the time of firing, it was blended more than the theoretical value. The raw material mixture is filled in a crucible, and heat treatment is performed for 3 hours at a temperature of 1000 ° C. in a nitrogen gas atmosphere with a gas pressure of 0.92 MPa (1.02 MPa in absolute pressure) as a gauge pressure, and nitriding of Example 1 A powder of the phosphor was obtained.

(Example 2)
A nitride phosphor powder of Example 2 was obtained under the same conditions as in Example 1 except that the temperature of the heat treatment was changed to 1100 ° C.

(Example 3)
The nitride phosphor powder of Example 3 was obtained under the same conditions as in Example 1 except that the temperature of the heat treatment was changed to 1200 ° C.

(Example 4)
The nitride phosphor powder of Example 4 was obtained under the same conditions as in Example 1 except that the temperature of the heat treatment was changed to 1300 ° C.

(Example 5)
A nitride phosphor powder of Example 5 was obtained under the same conditions as in Example 1 except that the amount of charged Li was increased from 1.1 to 1.2.

(Example 6)
A nitride phosphor powder of Example 6 was obtained under the same conditions as in Example 3 except that the amount of charged Li was changed from 1.1 to 1.2 in Example 3.

(Comparative example 1)
The gas atmosphere is a mixed gas atmosphere of nitrogen (N ₂ ) / hydrogen (H ₂ ) = 9/1, the gas pressure is atmospheric pressure (1.0 kPa as gauge pressure, 0.10 MPa as absolute pressure), and the temperature is 1000 ° C. Under the same conditions as in Example 1 except that the heat treatment was performed for 3 hours, a powder of the nitride phosphor of Comparative Example 1 was obtained.

(Comparative example 2)
In Comparative Example 1, a powder of a nitride phosphor of Comparative Example 2 was obtained under the same conditions as Comparative Example 1 except that the heat treatment temperature was changed to 1100 ° C.

(Comparative example 3)
In Comparative Example 1, a powder of the nitride phosphor of Comparative Example 3 was obtained under the same conditions as Comparative Example 1 except that the heat treatment temperature was changed to 1200 ° C.

(Comparative example 4)
In Comparative Example 1, a powder of the nitride phosphor of Comparative Example 4 was obtained under the same conditions as Comparative Example 1 except that the heat treatment temperature was changed to 1300 ° C.

(Comparative example 5)
In Comparative Example 1, a powder of a nitride phosphor of Comparative Example 5 was obtained under the same conditions as Comparative Example 1 except that the gas atmosphere was changed to a nitrogen gas atmosphere.

(Comparative example 6)
In Comparative Example 1, a powder of a nitride phosphor of Comparative Example 6 was obtained under the same conditions as Comparative Example 1 except that the gas atmosphere was changed to a nitrogen gas atmosphere and the heat treatment temperature was changed to 1100 ° C.

(Comparative example 7)
In Comparative Example 1, a powder of a nitride phosphor of Comparative Example 7 was obtained under the same conditions as Comparative Example 1 except that the gas atmosphere was changed to a nitrogen gas atmosphere and the heat treatment temperature was changed to 1200 ° C.

(Comparative example 8)
The powder of the nitride phosphor of Comparative Example 8 was obtained under the same conditions as Comparative Example 1 except that the gas atmosphere was changed to a nitrogen gas atmosphere and the heat treatment temperature was changed to 1300 ° C. in Comparative Example 1.

<Evaluation>
(X-ray diffraction spectrum)
The X-ray diffraction spectrum (XRD) was measured about the obtained nitride fluorescent substance. The measurement was performed using CuK alpha ray, using Ultima IV made by Rigaku. An example of the obtained XRD pattern is shown in FIG.
As shown in FIG. 2, it was confirmed that the compounds of Comparative Example 1, Example 1 and Example 2 were compounds represented by SrLiAl ₃ N ₄ in composition.
In FIG. 2, the compound (SLAN) represented by SrLiAl ₃ N ₄ shown for reference in the order from the bottom, the nitride phosphor of Comparative Example 1, the nitride phosphor of Example 1, and the Example 2 The XRD pattern of nitride fluorescent substance is shown.

(Composition analysis)
The composition ratio of each element of Sr, Li, Eu and Al was determined by ICP emission analysis for the obtained nitride phosphor. Table 1 shows the results of calculating the chemical composition ratio of each element from the Li content ratio and the Eu content ratio at the time of preparation, and the obtained analysis values. The composition ratio of each element by composition analysis was determined using Al as a reference value 3.

(Average particle size)
The average particle size of the obtained nitride phosphor was measured. The average particle size of the obtained powder is as described in F.I. S. S. S. No. (Fisher Sub Sieve Sizer's No.), which refers to the average particle size obtained by air permeation method. Specifically, after taking a sample of 1 cm ³ min at an ambient temperature of 25 ° C and humidity of 70%, packing it into a special tubular container, flowing dry air at a constant pressure, reading the specific surface area from the differential pressure , Converted to the average particle size. The results are shown in Table 2.

(Light emission characteristics)
The emission characteristics of the obtained nitride phosphor were measured. The emission characteristics of the powder were measured using a spectrofluorimeter: F-4500 (manufactured by Hitachi High-Technologies Corporation) with a wavelength of excitation light of 460 nm. The relative emission intensity (relative Ip:%), peak wavelength (λp: nm), and half width (FWHM: nm) were determined from the obtained emission spectrum. The results are shown in Table 2. The relative emission intensity was determined based on the nitride phosphor of Comparative Example 1.
Further, FIG. 3 shows the emission spectra of the nitride phosphors obtained in Comparative Examples 1 and 2 and Examples 1 to 3 as representative examples of other examples and comparative examples. The emission spectrum of FIG. 3 shows the relative emission intensity to the wavelength.

(Reflectance)
The reflection spectrum was measured about the obtained nitride fluorescent substance. The reflection spectrum was measured using a spectrofluorimeter: F-4500 in the same manner as the light emission characteristics. In addition, CaHPO ₄ was used as a reference | standard of a reflectance.
The measurement of reflectance was performed at 1 nm intervals in the measurement range. The average reflectance in a wavelength range of 450 nm or more and 470 nm or less was calculated as an arithmetic average value by measuring the reflectance at 21 points of 450 nm or more and 470 nm or less. It calculated similarly about the average reflectance of 640 nm or more and 660 nm or less.
The ratio of reflectance at 650nm for the reflectivity at 460nm and ^(R 650 ^/ R ^460), the ratio of the average reflectance at 640nm or 660nm or less to the average reflectance at 450nm or 470nm or less ^{(R 640-660 /} R ^450-470) I asked for each.
FIG. 4 shows the reflection spectra of the nitride phosphors obtained in Comparative Examples 1 and 2 and Examples 1 to 3 as representative examples of other examples and comparative examples.

The composition ratios shown in Table 1 are determined using Al as a reference value 3. From the results of compositional analysis, it can be seen that Li is reduced from the amount of elements in the preparation. Moreover, the amount of decrease of Li is large when the temperature is high. On the other hand, in the examples, Sr and Li have numerical values close to the theoretical composition SrLiAl ₃ N ₄ . Comparing the comparative example and the example, it can be seen that the reduction of Li is suppressed in the example having a high gas pressure (gauge pressure). Further, Sr also tends to decrease in the comparative example, but it can be seen that the decrease is suppressed in the example.

Table 2 shows the average particle size and the light emission characteristics. The phosphors of Examples 1 to 6 all have higher relative luminescence intensity than Comparative Examples 1 to 8, and it can be seen that the luminescent characteristics are excellent. The emission peak wavelength is from 652 nm to 654 nm, and the half width is from 55 nm to 61 nm. The reflectance ratio (R ⁶⁵⁰ / R ⁴⁶⁰ ) of the reflectance at 650 nm with respect to the reflectance at 460 nm in Examples 1 to 6 is 2 or more, which is a numerical value higher than in Comparative Examples 1 to 8. The average reflectance ratio 40nm or 660nm or less of the average reflectance ^{(R 640-660)} 450nm or 470nm or less of the average reflectance ^{(R 450-470) (R 640-660 /} R 450-470) also 2 or more and It has become.
While the reflectance at 460 nm is higher than 35% for the reflectances of Comparative Examples 1 to 4, 7 and 8, the reflectance for Examples 1 to 6 is 35% or less, and the emission of light in the emission spectrum near 460 nm When used in a light emitting device provided with an excitation light source having a peak, it can be seen that there is high absorption of the excitation light and that it has characteristics such as a particle diameter suitable for use.
The reflectance ratio (R ⁶⁵⁰ / R ⁴⁶⁰ ) is considered to indicate the ratio of absorption of excitation light in the nitride phosphor to absorption at the emission wavelength. For example, when the absorption at the emission wavelength of the nitride phosphor is large, the emission actually taken out of the nitride phosphor is reduced even if the light is absorbed by absorbing the excitation light. That is, when the reflectance ratio (R ⁶⁵⁰ / R ⁴⁶⁰ ) is large, it indicates that the absorption of the excitation light is large and the absorption at the emission wavelength is small, which is an index of luminous efficiency. As a cause of the increase of the light emission intensity and the increase of the reflectance ratio (R ⁶⁵⁰ / R ⁴⁶⁰ ), the composition deviation is suppressed by applying a high pressure at the time of heat treatment, and the crystal shape approaches more ideal. It is thought that it is affecting.
The average particle diameter of each of the phosphor particles of Examples 1 to 6 is 4 μm or more, and is larger than the average particle diameter of Comparative Examples 3, 4, 7 and 8. In particular, the average particle diameter of each of the phosphor particles of Examples 2 to 6 is larger than 4.5 μm, and is larger than the average particle diameter of Comparative Examples 1 to 8. Thereby, it is considered that the relative light emission intensity is further improved.

(Examples 7 to 10, Comparative Example 9)
Nitride phosphors of Examples 7 to 10 and Comparative Example 9 under the same conditions as in Example 2 except that the Li amount ratio and the Eu amount ratio at the time of preparation are changed as shown in Table 3 in Example 2. The respective powders were obtained. In addition, Eu amount ratio was adjusted so that the value which totaled Sr amount ratio may be set to 1, when setting Al to three.
The evaluations were performed in the same manner as described above for the powders of the nitride phosphors of Examples 7 to 10 and Comparative Example 9 obtained. Composition ratios from composition analysis are shown in Table 3, and evaluation results of light emission characteristics are shown in Table 4.

As shown in Table 3, the Eu content ratio determined from the composition analysis was almost the same as the charged Eu content ratio. The Li amount ratio and the Sr amount ratio obtained from the composition analysis were lower than the preparation amount ratio, and the Sr amount ratio was 0.900 to 0.958, and the Li amount ratio was 0.838 to 0.930.
As shown in Table 4, even in the nitride phosphors of Examples 7 to 9 in which the amount ratio of Eu is changed, the relative emission intensity tends to be as high as that in Example 2, and the reflectance ratio (R ⁶⁵⁰ / R ⁴⁶⁰ ) is also found to be equal to or higher than that of the second embodiment. Moreover, although the nitride fluorescent substance of Example 10 whose Eu amount ratio is 0.05 higher than Example 2 and Examples 7-9 has a relative luminous intensity lower than Example 2 or Examples 7-9. The reflectance ratio (R ⁶⁵⁰ / R ⁴⁶⁰ ) is found to be higher than that of Comparative Example 9 as in Example 2. On the other hand, the nitride phosphor of Comparative Example 9 having a Eu content ratio of 0.001 lower than that of Example 2 and Examples 7 to 10 has a relative emission intensity lower than that of Example 2 or Examples 7 to 10, and reflection is The ratio ratio (R ⁶⁵⁰ / R ⁴⁶⁰ ) is low.

(Example 11)
In Example 2, a powder of the nitride phosphor of Example 11 was obtained under the same conditions as in Example 2 except that a part of Sr was changed to Ca and the Eu content ratio was further changed.
In Example 11, the raw material mixture was blended so that Sr: Ca: Li: Eu: Al = 0.891: 0.1: 1.2: 0.009: 3.0.
The obtained powder of the nitride phosphor of Example 11 was evaluated in the same manner as described above. Composition ratios from composition analysis are shown in Table 5, and evaluation results of light emission characteristics are shown in Table 6.

(Example 12)
A nitride phosphor powder of Example 12 was obtained under the same conditions as in Example 2 except that a part of Sr was changed to Ba in Example 2.
In Example 12, the raw material mixture was blended so as to be Sr: Ba: Li: Eu: Al = 0.893: 0.1: 1.1: 0.007: 3.0.
The obtained powder of the nitride phosphor of Example 12 was evaluated in the same manner as described above. Composition ratios from composition analysis are shown in Table 5, and evaluation results of light emission characteristics are shown in Table 6.

As shown in the compositional ratio from compositional analysis in Table 5, it can be seen that the nitride phosphors of Examples 11 and 12 contain Ca and Ba in addition to Sr. Further, as shown in Table 6, with respect to the light emission characteristics of the nitride phosphors of Examples 11 and 12, the relative light emission intensity and the reflectance ratio (R ⁶⁵⁰ / R ⁴⁶⁰ ) are higher than those of the comparative examples as in the other examples. It is understood that the light emission characteristics are high and excellent.

Example A
The light emitting device according to Example A is an LED having a light emission peak wavelength of 453 nm, the nitride phosphor of Example 2 as the first phosphor, and β sialon fluorescence having the light emission peak wavelength at 544 nm as the second phosphor. body _{(Si 6-p Al p O} p N 8-p: Eu, 0 <p ≦ 4.2) in combination with, was prepared in the usual way. The chromaticity of mixed-color emission of the light emitting device in which the blue LED and each phosphor were combined was adjusted to around x = 0.25 and y = 0.20 in the chromaticity coordinates (x, y).

(Comparative example A)
The light emitting device according to Comparative Example A was manufactured in the same manner as Example A except that the nitride phosphor of Comparative Example 2 was used as the first phosphor. Further, as in Example A, the chromaticity of mixed-color emission of the light emitting device was adjusted to the vicinity of the above-mentioned chromaticity coordinates.

  The chromaticity coordinates and luminous flux ratios of the light emitting devices according to Example A and Comparative Example A are shown in Table 7. The emission spectrum is shown in FIG. The emission spectrum of FIG. 9 shows the relative emission intensity with respect to the wavelength. The luminous flux of the light emitting device was measured using an integral type total luminous flux measuring device, and the luminous flux ratio based on Comparative Example A is shown in the following table.

  As shown in Table 7, the luminous flux ratio of the light emitting device of Example A using the nitride phosphor of Example 2 is about 20% higher than that of Comparative Example A using the nitride phosphor of Comparative Example 2. The As shown in FIG. 9, the emission spectrum was substantially the same spectral shape regardless of which nitride phosphor was used, but the relative emission intensity in Example A was larger than that in Comparative Example A.

Example B
The light emitting device according to Example B includes an LED having an emission peak wavelength of 455 nm, the nitride phosphor of Example 2 as the first phosphor, and Y ₃ (Al, Ga) ₅ O ₁₂ as the second phosphor. : It combined with the fluorescent substance which has a composition of: Ce, and was produced by the normal method. The chromaticity of mixed-color emission of a light emitting device in which a blue LED and each phosphor were combined was adjusted to around x = 0.34 and y = 0.35 in the chromaticity coordinates (x, y).

(Comparative Example B)
The light emitting device according to Comparative Example B was manufactured in the same manner as in Example B except that the nitride phosphor of Comparative Example 2 was used as the first phosphor. Further, as in Example B, the chromaticity of mixed-color light emission of the light emitting device was adjusted to the vicinity of the above-mentioned chromaticity coordinates.

  The chromaticity coordinates and luminous flux ratios of the light emitting devices according to Example B and Comparative Example B are shown in Table 8. The emission spectrum is shown in FIG. The emission spectrum of FIG. 10 shows the relative emission intensity with respect to the wavelength. The luminous flux of the light emitting device was measured using an integral type total luminous flux measuring device, and the luminous flux ratio based on Comparative Example B is shown in the following table.

  As shown in Table 8, the luminous flux ratio of the light emitting device of Example B using the nitride phosphor of Example 2 is about 3% higher than that of Comparative Example B using the nitride phosphor of Comparative Example 2. The Example B was higher than Comparative Example B with respect to the average color rendering index Ra. As shown in FIG. 10, the emission spectrum was substantially the same spectral shape regardless of which phosphor was used, but the relative emission intensity in Example B was larger than that in Comparative Example B.

  Since the nitride fluorescent substance of this embodiment is excellent in luminous efficiency, a light emitting device with a large luminous flux can be provided by using this nitride fluorescent substance.

  A light emitting device using the nitride phosphor of the present disclosure can be suitably used as a light source for illumination and the like. In particular, it can be suitably used for an illumination light source extremely excellent in light emission characteristics using a light emitting diode as an excitation light source, an LED display, a backlight light source for liquid crystal, a traffic light, an illumination switch, various sensors, various indicators and the like.

  10: light emitting element, 50: sealing member, 71: first phosphor, 72: second phosphor, 100: light emitting device

Claims (11)

The manufacturing method of the nitride phosphor having a composition represented by the following formula (I), a raw material mixture containing more than the stoichiometric amount of metal compound containing an element represented by M ^b, the temperature is 1000 ° C. 1,400 A method for producing a nitride phosphor, comprising treating in an atmosphere containing nitrogen gas at a temperature of 0.2 ° C. or less and 0.2 MPa or more and 1.0 MPa or less as a gauge pressure .
M ^a _w M ^b _x Eu _y Al ₃ N _z (I)
(Wherein, M ^a is at least one element selected from the group consisting of Ca, Sr, Ba and Mg, and M ^b is at least one element selected from the group consisting of Li, Na and K And w, x, y and z are respectively 0.8 ≦ w <1.0, 0.5 ≦ x <1.0, 0.001 <y ≦ 0.1, z = (2/3) w + (1/3) x + (2/3) y + 3 ) The production of a nitride phosphor according to claim 1 , wherein the raw material mixture contains at least one metal compound selected from the group consisting of a hydride, a nitride and a fluoride, which contains the metal element constituting the composition. Method. Manufacturing method of the nitride phosphor according to claim 1 or 2 pressure is less than 1.0 MPa 0.8 MPa or more as a gauge pressure. The raw material mixture, a nitride of element represented by M ^a, aluminum hydride compounds containing an element represented by M ^b, according to claims 1 containing aluminum nitride and fluorinated europium 1 wherein either 3 Method of producing a nitride phosphor . The method for producing a nitride phosphor according to any one of claims 1 to 4, wherein the temperature at which the raw material mixture is treated is 1100 ° C or more and 1300 ° C or less . The method for producing a nitride phosphor according to any one of claims 1 to 5, wherein an average particle diameter of the nitride phosphor is 4.0 μm or more and 20 μm or less . The nitride fluorescent light according to any one of claims 1 to 6, wherein the nitride phosphor has an emission peak wavelength in a range of 630 nm to 670 nm when excited with light in a wavelength range of 400 nm to 570 nm. How to make the body. The method for producing a nitride phosphor according to any one of claims 1 to 7, wherein a ratio of a reflectance at 650 nm to a reflectance at 460 nm is 2 or more. The method for producing a nitride phosphor according to any one of claims 1 to 8, wherein the nitride phosphor has a reflectance of 30% or less at 460 nm. In the above formula (I), M ^a Contains at least one of Ca and Sr, M ^b The manufacturing method of the nitride fluorescent substance of any one of Claims 1 to 9 containing Li. The method for producing a nitride phosphor according to any one of claims 1 to 10, wherein in the formula (I), x is 0.7 or more and less than 1.0.