Phosphor, light emitting device, lighting device, image display device, and indicator lamp for vehicles

Abstract

The purpose of the present invention is to provide a phosphor having a narrow peak half-value width and / or a light emitting device having excellent emission color or conversion efficiency or both. The present invention pertains to a phosphor that includes a crystal phase having a composition represented by formula [1], wherein the phosphor includes stacking faults and the maximum spacing between stacking faults is 50 nm or more in the direction perpendicular to the stacking faults, or the phosphor includes a crystal phase A and a crystal phase B, both the crystal phase A and the crystal phase B have a composition represented by formula [1], and the crystal phase A and the crystal phase B are different in space group from each other.　RexMA1-xMBbMCcDd [1] (The symbols in formula [1] are as defined in the specification.)

Description

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

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

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

[0003] Recently, white light emitting LEDs of this type have been used that use a blue LED chip on which a nitride phosphor that emits red light and a phosphor that emits green light are excited by blue light from the blue LED chip. In particular, nitride phosphors that emit red light have the general formula CaAlSi(N,O) ３ (hereinafter, sometimes referred to as "CASN phosphor"), or (Sr,Ca)AlSi(N,O) ３ Fluorescent materials have been developed in which an activator is added to a host material represented by the formula (hereinafter, sometimes referred to as "SCASN phosphors"). CASN phosphors and SCASN phosphors are known to have excellent luminous intensity or quantum efficiency, etc., due to research into improvements and reliability, as well as a track record of specifications.

[0004] Electrochemical and Solid-State Letters, vol. 9, H22 (2006)

[0005] However, when a phosphor has a wide full width at half maximum (FWHM) of its emission spectrum, the emission of wavelengths far from the desired emission peak wavelength increases, and the emission color exhibiting the desired chromaticity coordinates may not be obtained. In addition, in the case of red phosphors, the emission of wavelengths with low luminous efficiency, such as 700 nm or more, increases, which contributes to a decrease in the conversion efficiency of the light-emitting device. For these reasons, there is a demand for phosphors with narrower full widths at half maximum. In view of this, an object of the present invention is to provide a phosphor with a narrow full width at half maximum and / or a light-emitting device with good emission color, conversion efficiency, or both.

[0006] The present inventors have found that the above problems can be solved by using a phosphor having specific crystal structure characteristics in a general formula CASN phosphor or a SCASN phosphor, and have thus completed the present invention.

[0007] Some non-limiting embodiments are described below. Note that the present invention also includes embodiments that further include some or all of the features of one or more other embodiments in addition to any of the embodiments described below.

[0008] That is, the gist of the present invention is as follows.

[0009] A first aspect of the present invention relates to a phosphor including a crystalline phase having a composition represented by the following formula [1], which includes stacking faults, and the maximum distance between stacking faults in a direction perpendicular to the stacking faults is 50 nm or more. ｘ MA １－ｘ MB ｂ MC ｃ D ｄ [1] (In the above formula [1], Re includes one or more elements selected from the group consisting of Eu, Mn, Ce, Pr, Nd, Sm, Tb, Dy, Ho, Er, Tm, and Yb; MA includes one or more elements selected from the group consisting of Ca, Sr, Ba, and Mg; MB includes one or more elements selected from the group consisting of Al, B (boron), Ga, In, and Sc; MC includes one or more elements selected from the group consisting of Si, Ge, Ti, and Hf; D is one or more elements selected from the group consisting of N (nitrogen), O (oxygen), F (fluorine), Cl, Br, and I (iodine), and includes at least N (nitrogen); and x, b, c, and d each independently satisfy the following: 0.0<x≦0.2 0.7≦b≦1.3 0.7≦c≦1.3 2.4≦d≦3.6)

[0010] A second aspect of the present invention relates to the phosphor of the first aspect, wherein the maximum distance between stacking faults in a direction perpendicular to the stacking faults is 100 nm or more.

[0011] Aspect 3 of the present invention is the phosphor of aspect 1 or 2, wherein the density of the stacking faults in the normal direction is 2×10 ５ cm－１ That is all about the phosphor.

[0012] A fourth aspect of the present invention is a phosphor according to any one of the first to third aspects, wherein the space group of the crystalline phase having the composition represented by the formula [1] is Cmc2 １ , Pbcn, P1, P-1, and Cmc2 １ and Pbcn, and the space group belongs to the maximal non-isomorphic subgroup derived from Pbcn.

[0013] A fifth aspect of the present invention relates to a phosphor comprising a crystalline phase A and a crystalline phase B, wherein the crystalline phase A and the crystalline phase B both have a composition represented by the following formula [1], and the crystalline phase A and the crystalline phase B have different space groups. ｘ MA １－ｘ MB ｂ MC ｃ D ｄ [1] (In the above formula [1], Re includes one or more elements selected from the group consisting of Eu, Mn, Ce, Pr, Nd, Sm, Tb, Dy, Ho, Er, Tm, and Yb; MA includes one or more elements selected from the group consisting of Ca, Sr, Ba, and Mg; MB includes one or more elements selected from the group consisting of Al, B (boron), Ga, In, and Sc; MC includes one or more elements selected from the group consisting of Si, Ge, Ti, and Hf; D is one or more elements selected from the group consisting of N (nitrogen), O (oxygen), F (fluorine), Cl, Br, and I (iodine), and includes at least N (nitrogen); and x, b, c, and d each independently satisfy the following: 0.0<x≦0.2 0.7≦b≦1.3 0.7≦c≦1.3 2.4≦d≦3.6)

[0014] A sixth aspect of the present invention relates to the phosphor of the fifth aspect, wherein the volume occupancy of the crystalline phase A is 60% or more but less than 100% when the total volume occupancy of the crystalline phase A and the crystalline phase B is 100%.

[0015] A seventh aspect of the present invention is the phosphor of the fifth or sixth aspect, wherein the space groups of the crystalline phase A and the crystalline phase B having the composition represented by the formula [1] are both Cmc2 １ , Pbcn, P1, P-1, and Cmc2 １ and Pbcn, and the space group belongs to the maximal non-isomorphic subgroup derived from Pbcn.

[0016] Aspect 8 of the present invention relates to a light emitting device comprising: a first light emitter; and a second light emitter that emits visible light when irradiated with light from the first light emitter, wherein the second light emitter includes the phosphor of any one of Aspects 1 to 7.

[0017] A ninth aspect of the present invention relates to the light-emitting device of the eighth aspect, wherein the second light-emitting body includes at least a red phosphor, and further includes a green phosphor and / or a yellow phosphor, and includes the phosphor of any one of the first to seventh aspects as the red phosphor or the yellow phosphor.

[0018] A tenth aspect of the present invention relates to the light emitting device of the ninth aspect, wherein the green phosphor and / or the yellow phosphor includes at least one phosphor selected from the group consisting of a garnet-based phosphor, a silicate-based phosphor, a nitride phosphor, and an oxynitride phosphor.

[0019] An eleventh aspect of the present invention relates to a lighting device including the light-emitting device according to any one of the eighth to tenth aspects as a light source.

[0020] A twelfth aspect of the present invention relates to an image display device including the light-emitting device according to any one of the eighth to tenth aspects as a light source.

[0021] A thirteenth aspect of the present invention relates to a vehicle indicator lamp including the light-emitting device according to any one of the eighth to tenth aspects as a light source.

[0022] According to the present invention, it is possible to provide a phosphor with a narrow half-width peak and / or a light-emitting device with good emission color, good conversion efficiency, or both.

[0023] FIG. 1A is a schematic diagram of a sheet-like structure sheet A for explaining the crystal structure of CASN and a phosphor according to one embodiment of the present invention. FIG. 1B is a schematic diagram of a sheet-like structure sheet B for explaining the crystal structure of CASN and a phosphor according to one embodiment of the present invention. FIG. 1C is a schematic diagram of the crystal structure of a general CASN phosphor. FIG. 1D is a schematic diagram of the crystal structure of a phosphor according to one embodiment of the present invention. FIG. 2A is a diagram showing a selected-area diffraction pattern in the

[100] direction obtained by observing the phosphor of Example 1 with a transmission electron microscope. FIG. 2B is a diagram of FIG. 2A with an explanation added to show the position of the diffraction spot indicating the (001) plane. FIG. 2C is a diagram showing a selected-area diffraction pattern in the

[100] direction obtained by observing the phosphor of Comparative Example 1 with a transmission electron microscope. FIG. 3A is a diagram showing a bright-field image obtained by observing the phosphor of Example 1 from the

[100] direction with a transmission electron microscope. FIG. 3B is a diagram showing a bright-field image obtained by observing the phosphor of Comparative Example 1 from the

[100] direction with a transmission electron microscope. Fig. 4A is a diagram showing a selected-area diffraction pattern of a transmission electron microscope in a circular region with a diameter of 500 nm of the phosphor of Example 1. Fig. 4B is a diagram showing a central enlargement of a convergent-beam electron diffraction (CBED) pattern of the phosphor of Example 1 observed from the

[100] direction. Fig. 5A is a diagram showing an annular bright-field image using an atomic-resolution aberration-corrected scanning transmission electron microscope, observed from the

[100] direction of a region of the phosphor of Example 1 that is free of stacking faults or a region consisting only of crystalline phase A of the phosphor of Example 1. Fig. 5B is a diagram showing an enlargement of Fig. 5A. Fig. 6A is a diagram showing an annular bright-field image of a phosphor having the same composition as Example 1, in which the space group is Cmc2. １FIG. 6B is a diagram showing a simulated image of a STEM bright-field image that should appear theoretically when the space group is assumed to be Pbcn for a phosphor having the same composition as in Example 1. FIG. 7A is a diagram showing an integrated differential phase contrast image obtained using an atomic resolution aberration-corrected scanning transmission electron microscope, in which a region without stacking faults in the phosphor of Example 1 or a region consisting only of crystalline phase A in the phosphor of Example 1 is observed from the

[100] direction. FIG. 7B is a diagram showing atomic modeling derived from FIG. 7A. FIG. 8A is a diagram showing normalized absorption spectra of the phosphors according to Example 1 and Comparative Example 1. FIG. 8B is a diagram showing normalized emission spectra of the phosphors according to Example 1 and Comparative Example 1.

[0024] The present invention will be described below with reference to embodiments and examples, but the present invention is not limited to the following embodiments and examples, and can be modified and implemented as desired within the scope of the gist of the present invention.

[0025] <Composition of phosphor> A phosphor according to one embodiment of the present invention is a phosphor including a crystalline phase having a composition represented by the following formula [1], including stacking faults, and the maximum distance between the stacking faults in a direction perpendicular to the stacking faults is 50 nm or more (hereinafter, this form will be referred to as "embodiment A"). Also, a phosphor according to one embodiment of the present invention is a phosphor including a crystalline phase A and a crystalline phase B, each of which has a composition represented by the following formula [1], and the crystalline phases A and B have different space groups (hereinafter, this form will be referred to as "embodiment B"). Hereinafter, the phosphor corresponding to at least one of embodiment A and embodiment B may be referred to as a "phosphor according to embodiment 1". Re ｘ MA １－ｘ MB ｂ MC ｃ D ｄ[1] (In the above formula [1], Re includes one or more elements selected from the group consisting of Eu, Mn, Ce, Pr, Nd, Sm, Tb, Dy, Ho, Er, Tm, and Yb; MA includes one or more elements selected from the group consisting of Ca, Sr, Ba, and Mg; MB includes one or more elements selected from the group consisting of Al, B (boron), Ga, In, and Sc; MC includes one or more elements selected from the group consisting of Si, Ge, Ti, and Hf; D is one or more elements selected from the group consisting of N (nitrogen), O (oxygen), F (fluorine), Cl, Br, and I (iodine), and includes at least N (nitrogen); and x, b, c, and d each independently satisfy the following: 0.0<x≦0.2 0.7≦b≦1.3 0.7≦c≦1.3 2.4≦d≦3.6)

[0026] In the formula [1], Re includes one or more elements selected from the group consisting of europium (Eu), manganese (Mn), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), and ytterbium (Yb), preferably including at least Eu or Ce, and more preferably including at least one element selected from the group consisting of Eu and Ce. In an embodiment in which Re includes Eu, the proportion of europium (Eu) relative to the total Re activator elements is preferably 50 mol% or more, more preferably 70 mol% or more, and particularly preferably 90 mol% or more. By including an appropriate amount of Re element in the phosphor, a phosphor exhibiting good luminescence intensity can be obtained.

[0027] In the formula [1], MA includes one or more elements selected from the group consisting of calcium (Ca), strontium (Sr), barium (Ba), and magnesium (Mg). Preferably, MA includes one or more elements selected from the group consisting of Ca or Sr. In one embodiment, the elements included in MA account for 70 mol % or more, preferably 80 mol % or more, more preferably 90 mol % or more, and even more preferably 95 mol % or more of the total MA. In a specific embodiment, MA consists of the above elements.

[0028] In the formula [1], MB contains one or more elements selected from the group consisting of aluminum (Al), boron (B), gallium (Ga), indium (In), and scandium (Sc), preferably one or more elements selected from the group consisting of Al, B, and Ga, and more preferably at least Al. In one embodiment, the elements contained in the MB account for 70 mol % or more, preferably 80 mol % or more, more preferably 90 mol % or more, and even more preferably 95 mol % or more of the entire MB, and in a specific embodiment, MB consists of the above-mentioned elements.

[0029] In the formula [1], MC includes one or more elements selected from the group consisting of silicon (Si), germanium (Ge), titanium (Ti), and hafnium (Hf), and preferably includes at least Si. In one embodiment, the elements included in MC account for 70 mol % or more, preferably 80 mol % or more, more preferably 90 mol % or more, and even more preferably 95 mol % or more of the entire MC. In a specific embodiment, MC consists of the above elements.

[0030] In the formula [1], D contains one or more elements selected from the group consisting of nitrogen (N), oxygen (O), fluorine (F), chlorine (Cl), bromine (Br), and I (iodine), preferably containing at least N (nitrogen) or O (oxygen), more preferably containing at least N (nitrogen). In an embodiment in which D contains nitrogen (N) or oxygen (O), the total proportion of nitrogen (N) and oxygen (O) relative to the total of D is usually 70 mol % or more, preferably 80 mol % or more, more preferably 90 mol % or more, and even more preferably 95 mol % or more. Nitrogen (N) or oxygen (O) may partially contain other elements, such as fluorine (F), chlorine (Cl), bromine (Br), or iodine (I). In the present invention, "containing an element" refers to both a form in which the element is substituted and a form in which the element is contained without being substituted.

[0031] In addition to the intended elements, MA, MB, MC, D, and Re may contain unintentionally or unavoidably mixed impurity elements with similar properties. However, these elements are not excluded by the present invention as long as they do not impair the essence or effect of the present invention or the effect of the present invention. The impurity elements may be elements not intended to be included in each site among the elements listed as elements that may be included in MA, MB, MC, D, and Re, or elements other than those listed. For example, when a phosphor is manufactured with an intended composition in which MA is composed of Ca and / or Sr, elements other than the aforementioned Ca and Sr may be unavoidably mixed into the raw materials, or trace amounts may be mixed in when a flux (flux) is used in the phosphor manufacturing process, resulting in partial substitution of MA with other elements such as Ba and Mg. However, these elements are not excluded by the present invention as long as they do not impair the essence or effect of the present invention or the effect of the present invention. The same applies when the above "MA" is replaced with MB, MC, D, or Re, the above "Ca or Sr" is replaced with one or more of the elements listed as elements that can be contained at each site, and the above "other elements such as Ba, Mg, etc." is replaced with "other elements."

[0032] O (oxygen) may be intentionally included for the purpose of maintaining the charge balance of the entire phosphor or for adjusting the peak wavelength. However, even when the phosphor is produced with the intention of not containing oxygen, it may be mixed in as an impurity in the raw metal, or may be mixed in during the production process, such as the crushing step or nitriding step. Thus, in the phosphor according to one embodiment of the present invention, oxygen may be inevitably mixed in, even if it is not intended. The allowable oxygen content when formula [1] is produced with the intention of not containing oxygen is usually 10% by mass or less, preferably 6% by mass or less, more preferably 4% by mass or less, and even more preferably 2% by mass or less, within a range in which a decrease in the luminescence characteristics of the phosphor is acceptable.

[0033] Like oxygen, halogen elements may also be contained in the phosphor according to embodiment 1. Possible reasons for halogen elements being contained in the phosphor include being mixed in as impurities in raw metals, or being introduced during the manufacturing process such as a pulverization step or a nitriding step. In particular, when a halide is used as a flux, halogen elements may end up being contained in the phosphor.

[0034] As described above, examples of the halogen element to be mixed include fluorine, chlorine, bromine, and iodine. The halogen element content is preferably 1% by mass or less, more preferably 0.5% by mass or less, so that the light-emitting properties of the phosphor are acceptable.

[0035] In formula [1], x, b, c, and d respectively represent the molar equivalents of Re, MB, MC, and D when the total amount of MA + Re is 1. The ideal ratio for a stable crystal structure is when b, c, and d are 1, 1, and 3, respectively. However, in reality, the values ​​of b, c, and d may vary somewhat from the ideal ratio due to various factors such as single atom deficiency, changes in composition due to oxidation of the phosphor surface, heterogeneous phases, and charge compensation. However, these variations are not excluded by the present invention as long as they do not impair the essence or the effects of the present invention. Specifically, the ranges of values ​​that can be tolerated for x, b, c, and d are listed below.

[0036] The value of x is greater than 0.0 and less than or equal to 0.20. It is preferably 0.00001 or greater, more preferably 0.001 or greater, even more preferably 0.005 or greater, and is preferably 0.15 or less, more preferably 0.10 or less, even more preferably 0.05 or less, and particularly preferably 0.01 or less. When the value of x is within the above range, good luminescence intensity can be obtained.

[0037] The range of b is 0.7 or more and 1.3 or less, preferably 0.8 or more, more preferably 0.9 or more, and even more preferably 0.95 or more, and is preferably 1.2 or less, more preferably 1.1 or less, and even more preferably 1.05 or less.

[0038] The range of c is 0.7 or more and 1.3 or less, preferably 0.8 or more, more preferably 0.9 or more, and even more preferably 0.95 or more, and is preferably 1.2 or less, more preferably 1.1 or less, and even more preferably 1.05 or less.

[0039] The range of d is 2.4 or more and 3.6 or less, preferably 2.6 or more, more preferably 2.7 or more, and even more preferably 2.8 or more, and is preferably 3.4 or less, more preferably 3.3 or less, and even more preferably 3.2 or less.

[0040] When b, c, and d are within the above ranges, the crystal structure of the phosphor is stabilized.

[0041] <Crystal Structure> (Crystal Structure of Phosphor in Embodiment A) Regarding embodiment A, the phosphor according to embodiment 1 is a phosphor that includes a crystalline phase having a composition represented by formula [1] and includes stacking faults. In general, a perfect crystal can be considered a state or structure in which the atomic planes constituting the crystal are repeatedly stacked with a certain regularity. Planar defects that occur when the regularity of the stacking is disrupted are called stacking faults. Specific examples of stacking faults include those in which a necessary layer is missing, an extra layer is inserted, or stacking occurs in an order different from the original order.

[0042] Next, the crystal structure of the known CASN phosphor will be described. As shown in FIG. 1C, the crystal structure of the CASN phosphor is such that AlN is formed on the bc plane of the crystal lattice or on a plane parallel to the lattice plane represented by Miller indices (100). ４ or SiN ４It has a sheet-like structure in which tetrahedra spread out sharing vertices (hereinafter, this may be referred to as "sheet A"; see FIG. 1A), and can be expressed as a structure in which sheets A are stacked in the a-axis direction (reference literature: Electrochemical and Solid-State Letters, vol. 9, H22 (2006), etc.). In FIGS. 1A to 1D, horizontally striped circles represent MA sites (Ca and Sr sites in CASN and SCASN phosphors) in the formula [1], vertically striped circles represent MB and MC sites (Si and Al sites in CASN and SCASN phosphors), and white circles represent D sites (N sites in CASN and SCASN phosphors). In addition, solid lines represent lines connecting D sites, and dashed lines represent lines connecting D sites on the back side of the paper to other D sites.

[0043] As shown in FIG. 1D, a phosphor according to one embodiment of the present invention has a stacking structure similar to that of a CASN phosphor as a main phase, and includes stacking faults in which a layer structure in which sheet A is rotated 180° with respect to the a-axis (hereinafter, this may be referred to as "sheet B"; see FIG. 1B) is inserted partially or locally.

[0044] In a phosphor according to one embodiment of the present invention, the maximum spacing between stacking faults in a direction perpendicular to the stacking faults is 50 nm or more, and the maximum spacing between the stacking faults is, in order from the most preferred embodiment, 2.0 μm or more, 1.5 μm or more, 1.2 μm or more, 1.0 μm or more, 800 nm or more, 500 nm or more, 300 nm or more, 200 nm or more, 100 nm or more, 80 nm or more, and the 50 nm or more.

[0045] By ensuring that the maximum spacing between stacking faults is within the above range, a phosphor with a narrower peak half-width can be obtained. The reason for this is believed to be, for example, the following reason. The formation of stacking faults, i.e., the expansion of dislocations, decomposes perfect dislocations into Shockley partial dislocations, significantly alleviating the residual stress in the phosphor, and localizing stacking faults and the Shockley partial dislocations in their vicinity. This ensures a wide region that can be considered nearly perfect crystal, free of dislocations and stacking faults. In the nearly perfect crystal region, the crystal field is stabilized, narrowing the radiation path and making it easier to obtain a phosphor with a narrow half-width. Furthermore, in regions with small strain, the Re element, which serves as the luminescence center, easily hops, resulting in a relatively uniform distribution of Re, i.e., a state in which the distances between the elements are nearly equal, and the crystal field around each Re element is also uniform. This brings the wavelengths at which the luminescence intensity due to each Re becomes maximum closer, potentially narrowing the half-width of the entire phosphor.

[0046] In one embodiment, the maximum spacing between stacking faults is 5.0 μm or less, and in this embodiment, the maximum spacing is preferably 4.0 μm or less, more preferably 3.0 μm or less. In this embodiment, when the spacing between stacking faults is within the above range, dislocation division and residual stress reduction occur due to the appropriate formation of stacking faults (dislocation extension) throughout the phosphor, resulting in a phosphor with fewer dislocations, ideally no dislocations at all. Note that the spacing is also referred to as the total area of ​​stacking faults per unit volume or the stacking fault probability, and is equivalent to the stacking fault density expressed in units of 1 / cm.

[0047] In this specification, the spacing between stacking faults is a value measured by the following method. Specifically, stacking faults can be observed as lines on the phosphor surface by observing the phosphor surface from a direction parallel to the stacking faults using a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM). When multiple stacking faults are present on the phosphor surface, the distance between the closest stacking faults is measured in a direction perpendicular to the stacking faults. Furthermore, when only one stacking fault is observed on the observation surface, the maximum distance from the observed stacking fault to the edge of the observation surface perpendicular to the stacking fault is defined as R. The maximum spacing between stacking faults can be considered to be at least R. In a specific embodiment, stacking faults exist on the bc plane or in the direction of Miller indices (100), and the spacing of the stacking faults is evaluated as the distance along the a-axis or in the

[100] direction.

[0048] In one embodiment, the density of the stacking faults in the normal direction is 2×10 ５ cm －１ or more, 1 × 10 ５ cm －１ More than 5 × 10 is preferable. ４ cm －１ The upper limit of the density of stacking faults in the normal direction is not particularly limited, but it is preferable that the upper limit is, for example, 2×10 ３ cm －１ Below, 1 x 10 ３ cm －１ Below, 1 x 10 ２ cm －１ The density of stacking faults in the normal direction can be set to 2×10 or less. ５ cm －１ If the crystal field is stable, the radiation path is narrowed, and a phosphor with a narrow half-value width is easily obtained, which is preferable.

[0049] In this specification, the density of stacking faults in the normal direction is a value measured by the following method. The density is the total area of ​​stacking faults in a unit volume, which is also called stacking fault probability and can be quantitatively expressed using a transmission electron microscope. An example of a method for measuring the total area (stacking fault probability) is shown below. When an electron beam is incident parallel to the stacking fault plane, a diffraction intensity derived from stacking faults is generated in the electron beam diffraction pattern. By adjusting the objective aperture to include this diffraction intensity, linear stacking fault contrasts can be confirmed in the electron microscope image projected and recorded on a CCD camera or film. The spacing of the linear stacking fault contrasts in the normal direction is determined and expressed in 1 / cm. For example, if the spacing of the linear stacking fault contrasts in the normal direction is 5 μm, the density of stacking faults in the normal direction is 2×10 ３ cm －１ If the interval is 500 nm, the density is 2×10 ４ cm －１ This becomes:

[0050] A phosphor according to one embodiment of the present invention includes a region that does not contain stacking faults. In a specific embodiment, the phosphor includes at least one region that does not contain stacking faults and has a width of 50 nm or more in a direction perpendicular to the stacking faults. Furthermore, the width of the region in the direction perpendicular to the stacking faults is, in order from the most preferred embodiment, 2.0 μm or more, 1.5 μm or more, 1.2 μm or more, 1.0 μm or more, 800 nm or more, 500 nm or more, 300 nm or more, 200 nm or more, 100 nm or more, 80 nm or more, and 50 nm or more. By having a region that does not contain stacking faults in the phosphor, a phosphor can be obtained that has a region that is close to a perfect crystal and has good emission peak intensity or peak half-width.

[0051] A phosphor according to a specific embodiment of the present invention includes a region that does not contain stacking faults and dislocations. The width of this region in a direction perpendicular to the stacking faults can be the same as the region that does not contain stacking faults. By including a region that does not contain stacking faults and dislocations in the phosphor, it is possible to obtain a phosphor that has a region that is closer to a perfect crystal and has good emission peak intensity or peak half-width.

[0052] In one embodiment, the space group of the crystalline phase having the composition represented by the formula [1] is Cmc2 １ , Pbcn, P1, P-1, and Cmc2 １ and Pbcn. In a preferred embodiment, the space group of the crystalline phase having the composition represented by the formula [1] is Cmc2. １ is.

[0053] (Crystal structure of phosphor in embodiment B) With regard to embodiment B, the phosphor of embodiment 1 includes crystalline phase A and crystalline phase B, both of which have a composition represented by formula [1], and the crystalline phase A and the crystalline phase B have different space groups.

[0054] The crystal structure of the CASN phosphor generally has AlN on the bc plane of the crystal lattice shown in Figure 2 of the reference (Electrochemical and Solid-State Letters, vol. 9, H22 (2006)) or on a plane parallel to the lattice plane represented by Miller indices (100). ４ or SiN ４ It has a sheet-like structure in which tetrahedrons spread out with their vertices shared (hereinafter, sometimes referred to as "sheet A"; see FIG. 1A), and can be expressed as a structure in which sheets A are stacked in the a-axis direction (see FIG. 1C).

[0055] On the other hand, in the phosphor according to embodiment 1, the crystalline phase A exhibits a stacking structure similar to that of CASN, and the crystalline phase B has a structure in which the minimum unit is a "sheet A → sheet B" stacking structure in which a structure in which the sheet A is rotated 180° about the a-axis (hereinafter sometimes referred to as "sheet B"; see FIG. 1B) is stacked with respect to the sheet A (see FIG. 1D). The insertion of sheet B corresponds to a stacking fault in which a phase that would not normally be stacked is inserted. It is believed that sheet B is inserted by dislocation expansion or the like, resulting in a phosphor containing crystalline phase B.

[0056] Furthermore, each crystalline phase B may independently consist of only one of the minimum units, or may have a structure in which the minimum unit is repeated a plurality of times. The number of repeats is usually 1 to 10, preferably 8 or less, more preferably 6 or less, even more preferably 4 or less, and particularly preferably 3 or less.

[0057] In one embodiment, when the total volume occupancy of the crystalline phase A and the crystalline phase B is 100%, the volume occupancy of the crystalline phase A is 60% or more but less than 100%. The volume occupancy of the crystalline phase A is preferably 65% ​​or more, more preferably 70% or more, even more preferably 75% or more, still more preferably 80% or more, particularly preferably 82% or more, and most preferably 85% or more. In a specific embodiment, the volume occupancy of the crystalline phase A is preferably 99% or less, more preferably 97% or less, and even more preferably 95% or less.

[0058] When the volume occupancy of the crystalline phase A is equal to or greater than the lower limit, a region close to perfect crystallinity can be sufficiently secured, and when the volume occupancy of the crystalline phase A is equal to or less than the upper limit, residual stress can be appropriately reduced throughout the entire phosphor.

[0059] In one embodiment, the maximum value of the spacing between the crystalline phases B in the direction perpendicular to the crystalline phases B is 50 nm or more, and preferably, in order from the most preferred embodiment, is 2.0 μm or more, 1.5 μm or more, 1.2 μm or more, 1.0 μm or more, 800 nm or more, 500 nm or more, 300 nm or more, 200 nm or more, 100 nm or more, 80 nm or more, and the 50 nm or more. When the spacing is equal to or greater than the lower limit, a region close to perfect crystal can be sufficiently secured, and when the spacing is equal to or less than the upper limit, residual stress can be appropriately reduced throughout the entire phosphor.

[0060] A phosphor having a narrower peak half-width can be obtained by ensuring that the volume fraction of the crystalline phase B is within the above range. This is thought to be due to the following reason, for example: it has been observed that phosphors containing crystalline phase B tend to have fewer dislocations than phosphors that do not contain crystalline phase B. Therefore, it is thought that the residual stress of the entire phosphor can be reduced by appropriately including crystalline phase B in the phosphor.

[0061] Furthermore, the presence of crystalline phases B at sufficient intervals ensures a wide region that can be said to be nearly perfectly crystalline and free of dislocations. In the nearly perfectly crystalline region, the crystal field is stabilized, narrowing the radiation path and making it easier to obtain a phosphor with a narrow half-width. In addition, in the region with small distortion, the Re element, which serves as the luminescence center, easily hops, resulting in a relatively uniform distribution of Re, i.e., a state in which the distances between them are nearly equal, and the crystal field around each Re element is also uniform. This brings the wavelengths at which the luminescence intensity due to each Re becomes maximum closer, which may result in a narrower half-width of the entire phosphor.

[0062] In one embodiment, the space groups of the crystalline phase A and the crystalline phase B having the composition represented by the formula [1] are both Cmc2 １ , Pbcn, P1, P-1, and Cmc2 １ and Pbcn. In a specific embodiment, the space group of the crystalline phase A is Cmc2. １ In a specific embodiment, the space group of the crystalline phase B is Pbcn, P1, or P-1, preferably Pbcn. In another specific embodiment, the crystalline phase B is in the space group Cmc2 １ This is because the crystalline phase B is Cmc2. １ This corresponds to the case where the atoms belong to a different space group than the atoms in the atomic resolution aberration-corrected scanning transmission electron microscope image described below.

[0063] <Method for determining the space group of a phosphor> A method for determining the space group of a phosphor according to the present invention will be described. Generally, in X-ray diffraction, the presence or absence of central symmetry cannot be determined due to the kinematic approximation, and as a result, the space group cannot be determined or may be mistakenly determined to be a different space group from the actual one.

[0064] (Method for determining the space group of a phosphor in embodiment A) In embodiment A, on the other hand, the presence or absence and distribution of regions that produce specific diffraction peaks can be identified, for example, by dark-field TEM imaging, and the space group can be more accurately identified by identifying the atomic arrangement, for example, using STEM.

[0065] For example, the space group can be confirmed by analyzing the convergent beam electron diffraction (CBED) pattern. １ The space group is defined by the existence of two mirror symmetries (m) and a two-fold helix axis parallel to the c-axis. If there is only one mirror symmetry, then P2 １ If there is no two-fold helix axis parallel to the c-axis direction, the structure becomes Pbcn.

[0066] (Method for Determining the Space Group of a Phosphor in Embodiment B) Regarding embodiment B, and further, a phosphor according to one embodiment of the present invention, in addition to a peak indicating the main phase, small peaks suggesting different phases are exhibited in the X-ray diffraction pattern. In the phosphor according to embodiment 1, peaks corresponding to crystalline phase A and crystalline phase B appear. As a result, if an attempt is made to determine the space group of a phosphor according to this embodiment solely from XRD observation, it may be concluded that the space group is different from the original space group.

[0067] For example, for a diffraction peak that would not normally appear, the presence or absence of a region in which the diffraction peak occurs and its distribution can be identified using a dark-field TEM image in the corresponding diffraction direction. In addition, the space group can be more accurately identified by identifying the arrangement of all atoms, including nitrogen atoms, using, for example, an atomic resolution aberration-corrected scanning transmission electron microscope (STEM) image. STEM methods that can accurately identify the atomic arrangement of so-called light elements such as nitrogen include low-angle annular dark-field (LAADF-STEM), annular bright-field (ABF-STEM), and integrated differential phase contrast (iDPC-STEM). １ The space group can be determined.

[0068] (Regarding the range of "same crystal structure" derived by transmission electron microscopy) The lattice constant changes when the constituent elements Sr, Ca, Si, Al, and N are replaced by other elements and when metallic elements such as Eu are dissolved, but it is known that the following (1) and (2) occur. (1) The atomic positions given by the crystal structure, the sites occupied by the atoms, and their coordinates do not change. (2) The atomic positions given by the crystal structure, the sites occupied by the atoms, and their coordinates do not change so much that the chemical bonds between the skeletal atoms are broken.

[0069] Furthermore, it is widely known as the Hume-Rothery rule that the crystal structure does not change when the atomic radius is substituted by a difference of up to 15%.

[0070] For example, if Ca (covalent bond radius: 180 pm) is replaced with Sr (covalent bond radius: 200 pm), the ratio becomes 100 x (200 - 180) / 180 = 11.11%, resulting in the same crystal structure.Furthermore, if N (covalent bond radius: 65 pm) is replaced with O (covalent bond radius: 60 pm), the ratio becomes 100 x (60 - 65) / 65 = 7.69%, resulting in the same crystal structure.

[0071] <Physical properties of phosphor> [Emitted color] With regard to embodiments A and B, by adjusting the chemical composition, etc., of the phosphor according to one embodiment of the present invention, it is possible to make it a phosphor that is excited by light with a wavelength of 360 nm to 550 nm and emits a desired emitted color, such as blue, blue-green, green, yellow-green, yellow, orange, or red.

[0072] [Emission Spectrum] The emission peak wavelength and its shape vary depending on the chemical composition of the phosphor or the type of Re element.

[0073] When Re contains Eu or is mainly composed of Eu, the emission peak wavelength λp (nm) in the emission spectrum of the phosphor is usually 570 nm or more and 700 nm or less. In this specification, "Re is mainly composed of Eu" means that Eu accounts for 50 mol % or more, preferably 60 mol % or more, more preferably 70 mol % or more, and even more preferably 80 mol % or more of the total Re. When the same expression is used for other elements contained in MA, MB, MC, and D, it means that the other elements account for mol % in the above range.

[0074] When MA is mainly composed of Ca, the emission peak wavelength is preferably 620 nm or more, more preferably 630 nm or more, and preferably 680 nm or less, more preferably 660 nm or less. When MA contains Sr, the emission peak wavelength is preferably 580 nm or more, and preferably 640 nm or less, more preferably 630 nm or less, and may be 620 nm or less, or 615 nm or less. When the emission peak wavelength λp (nm) is within the above range, it is preferable in that the emission characteristics as orange to red light are good.

[0075] Furthermore, the phosphor has a peak full width at half maximum (hereinafter appropriately abbreviated as "FWHM") in the above-mentioned emission spectrum of typically 50 nm to 100 nm, preferably 90 nm or less, more preferably 80 nm or less, and even more preferably 75 nm or less. When the FWHM is within the above range, when the phosphor is applied to a light-emitting device, the light-emitting device is favorable in both color rendering properties and conversion efficiency.

[0076] When Re contains Ce or is mainly composed of Ce, the emission spectrum of the phosphor has an emission peak wavelength λp (nm) of usually 545 nm or more, preferably 550 nm or more, more preferably 555 nm or more, and usually 580 nm or less, preferably 575 nm or less, more preferably 570 nm or less.

[0077] Furthermore, the phosphor has a peak full width at half maximum (hereinafter appropriately abbreviated as "FWHM") in the above-mentioned emission spectrum of typically 110 nm or more and 145 nm or less, preferably 140 nm or less, more preferably 135 nm or less, and even more preferably 130 nm or less. When the FWHM is within the above range, when the phosphor is applied to a light-emitting device, the light-emitting device is favorable in terms of both good color rendering properties and conversion efficiency.

[0078] When Re contains both Eu and Ce, or is mainly composed of Eu and Ce, the emission spectrum of the phosphor has an emission peak wavelength λp (nm) of usually 545 nm or more, preferably 550 nm or more, more preferably 555 nm or more, and usually 680 nm or less, preferably 670 nm or less, more preferably 660 nm or less.

[0079] Furthermore, the phosphor has a peak full width at half maximum (hereinafter appropriately abbreviated as "FWHM") in the above-mentioned emission spectrum of typically 110 nm or more and 165 nm or less, preferably 160 nm or less, more preferably 155 nm or less, and even more preferably 150 nm or less. When the FWHM is within the above range, when the phosphor is applied to a light-emitting device, the light-emitting device is favorable in terms of both good color rendering properties and conversion efficiency.

[0080] The light source for exciting the phosphor can be, for example, a GaN-based light-emitting diode that emits light at 445 to 460 nm. The method for measuring the emission spectrum of the phosphor according to embodiment 1 is not limited, but can be, for example, measured using a 150 W xenon lamp as the excitation light source and a fluorescence measuring device equipped with a multichannel CCD detector as the spectrum measuring device. The emission peak wavelength and peak half-width can be calculated from the obtained emission spectrum.

[0081] [Internal Quantum Efficiency] The higher the internal quantum efficiency of the phosphor according to embodiment 1, the more preferable it is. The value is usually 0.86 or more, preferably 0.88 or more, more preferably 0.9 or more, and particularly preferably 0.913 or more. A value within the above range is preferred in terms of high luminous efficiency.

[0082] <Method for manufacturing phosphor> With regard to embodiments A and B, the method for manufacturing the phosphor according to embodiment 1 is not particularly limited as long as the phosphor according to the present invention can be obtained, but examples thereof include a manufacturing method using an alloy as a phosphor raw material (hereinafter, sometimes referred to as the "alloy method") and a manufacturing method using nitrides of each element as a phosphor raw material (hereinafter, sometimes referred to as the "nitride method"). An example of a method by which the phosphor according to the present invention can be obtained is shown below.

[0083] [Alloying method] When the phosphor according to the first embodiment is produced by the alloying method, for example, when a phosphor having a composition represented by the formula [1] is produced, raw material metals or alloys (hereinafter, sometimes simply referred to as "raw material metals") are weighed so as to have a composition represented by the following formula [2]. Next, these are melted and alloyed to produce a phosphor raw material alloy, which is then pulverized to produce alloy powder, and the alloy powder is heated in a nitrogen-containing atmosphere to perform a nitriding treatment.

[0084] As will be explained in more detail below, when melting the raw metals as described below, it is preferable to melt Si metal and / or an alloy containing Si, which has a high melting point (high boiling point), and then melt Ca and Sr, which have a low melting point (low boiling point).

[0085] Re ｘ MA １－ｘ MBｂ MC ｃ [2] (In the above formula [2], Re, MA, MB, MC, x, b, and c are each defined as in the above formula [1].)

[0086] (Shape of raw material metal) There is no limitation on the shape of the raw material metal, but typically, granular or lumpy raw materials with a diameter of several mm to several tens of mm are used. When the phosphor according to the first embodiment contains Sr, it is preferable to use a lumpy raw material because Sr is chemically active.

[0087] (Melting of raw metal) The raw metal is weighed to have the desired composition and melted. There is no particular limitation on the method for melting the raw metal, and known techniques can be used. In addition, it is preferable to melt the raw metal by melting high-melting point (high-boiling point) Si metal and / or an alloy containing Si, and then melting low-melting point (low-boiling point) alkaline earth metal (Sr or Ca). The method for melting the raw metal in the present invention is not particularly limited, but examples thereof include resistance heating, electron beam, arc melting, and high-frequency induction heating.

[0088] (Casting of Molten Metal) Although a nitrogen-containing alloy can be produced directly from a molten alloy produced by melting raw metals, it is preferable to obtain a solidified body (alloy ingot) through a casting process in which the molten alloy produced by melting raw metals is poured into a mold and molded.

[0089] (Ingot Crushing) The alloy ingot obtained in the casting step is then crushed to prepare an alloy powder having a desired particle size and particle size distribution. Crushing methods include, for example, a dry method and a wet method using an organic solvent such as ethylene glycol, hexane, or acetone.

[0090] (Classification of alloy powder) The alloy powder pulverized in the pulverization step is adjusted to a desired mass median diameter D50 and particle size distribution using a sieving device using a mesh such as a vibrating screen or a sifter, an inertial classifier such as an air separator, or a centrifugal separator such as a cyclone.

[0091] The particle size of the alloy powder needs to be adjusted depending on the activity of the metal elements that make up the alloy powder, and the mass median diameter D50 is usually 100 μm or less, preferably 80 μm or less, and 0.1 μm or more, preferably 0.5 μm or more.

[0092] (Production of phosphor) The alloy powder is used to carry out a nitriding reaction. The nitriding treatment of the alloy powder is first carried out by filling the alloy powder into a crucible or a tray. Examples of materials for the crucible or tray used here include boron nitride, silicon nitride, aluminum nitride, molybdenum, and tungsten.

[0093] The crucible or tray filled with this alloy powder is placed in a heating furnace capable of atmosphere control, and then a nitrogen-containing gas is passed through the furnace to thoroughly replace the atmosphere within the system with the nitrogen-containing gas. If necessary, the system may be evacuated to a vacuum before the nitrogen-containing gas is passed through. The nitrogen-containing gas used in the nitriding treatment may be a gas containing nitrogen, such as nitrogen, ammonia, or a mixed gas of nitrogen and hydrogen.

[0094] The nitriding treatment is carried out by heating the chamber filled with or flowing with a nitrogen-containing gas. The pressure is not particularly limited as long as a phosphor according to one embodiment of the present invention can be obtained, but in the following exemplary embodiment, the pressure is preferably atmospheric pressure or higher to prevent the inclusion of oxygen from the atmosphere.

[0095] If the pressure of the nitrogen-containing gas in the nitriding treatment is set to atmospheric pressure or higher, it is possible to prevent a large amount of oxygen from being mixed in when the heating furnace is poorly sealed, thereby preventing a deterioration in the properties of the resulting phosphor. In one embodiment, the pressure of the nitrogen-containing gas is typically 50 MPa or higher in gauge pressure, preferably 100 MPa or higher, more preferably 120 MPa or higher, and even more preferably 150 MPa or higher, and typically 300 MPa or lower, preferably 250 MPa or lower. In a specific embodiment, the pressure is 150 MPa or higher and 250 MPa or lower. Furthermore, since pressure rise occurs with temperature rise, the target pressure can be obtained at the maximum temperature by adjusting the system to a lower temperature and pressure in accordance with the maximum temperature and maximum pressure and then raising the temperature.

[0096] In embodiments in which temperature and pressure adjustments are performed at the beginning of the nitriding treatment, the pressure increase rate after the initial temperature and pressure adjustments is typically 5.0 MPa / hr to 30 MPa / hr on average, expressed in MPa per hour, preferably 10 MPa / hr or more and preferably 20 MPa / hr or less. In one embodiment of embodiment A, by setting the pressure increase rate to be equal to or greater than the lower limit, firing can be completed within an appropriate time, and by setting the pressure increase rate to be equal to or less than the upper limit, a preferred phosphor containing stacking faults or having localized stacking faults can be obtained, as described above. In one embodiment of embodiment B, by setting the pressure increase rate to be equal to or greater than the lower limit, firing can be completed within an appropriate time, and by setting the pressure increase rate to be equal to or less than the upper limit, a preferred phosphor containing crystalline phase B or having crystalline phase B localized can be obtained, as described above.

[0097] The reason for this is that by slowing down the pressure increase rate, it takes a relatively long time to move from the stage where crystal nucleation mainly occurs to the stage where crystal growth mainly occurs, and during this time, the self-stress of dislocations is relaxed, promoting dislocation localization (also called dislocation recovery or dislocation polygonization), and in embodiment A, promoting dislocation extension (i.e., formation of stacking faults) may result in a phosphor containing stacking faults in an appropriate manner, while in embodiment B, promoting dislocation extension (i.e., formation of stacking faults, crystalline phase B) may result in a phosphor containing crystalline phase B in an appropriate manner.

[0098] The maximum temperature in the nitriding treatment is usually 800°C or higher, preferably 1200°C or higher, more preferably 1500°C or higher, and usually 2200°C or lower, preferably 2100°C or lower, more preferably 2000°C or lower. By setting the maximum temperature to 800°C or higher, it is possible to prevent the time required for the nitriding treatment from becoming long. On the other hand, by setting the maximum temperature to 2200°C or lower, it is possible to prevent the nitrides produced from volatilizing or decomposing, making it easier to obtain a phosphor having the desired composition.

[0099] The heating time during the nitriding treatment (holding time at the maximum temperature) may be the time required for the reaction between the alloy powder and nitrogen, but is usually 1 minute or more, preferably 10 minutes or more, more preferably 30 minutes or more, and even more preferably 60 minutes or more. By setting the heating time to 1 minute or more, the nitriding reaction progresses sufficiently, making it easier to obtain a phosphor with high properties. From the viewpoint of production efficiency, the upper limit of the heating time is usually 24 hours or less, preferably 20 hours or less, more preferably 15 hours or less, and even more preferably 12 hours or less. In a specific embodiment in which the maximum temperature is 1500°C or higher, the upper limit is preferably 8 hours or less, more preferably 5 hours or less, and even more preferably 3 hours or less.

[0100] After the nitriding treatment of the alloy, it is preferable to pulverize and classify the obtained phosphor. For example, the pulverization and classification treatment can be performed so that 90% or more of the obtained phosphor particles are particles preferably 5 μm to 30 μm, more preferably 7 μm to 27 μm, even more preferably 10 μm to 25 μm, and particularly preferably 12 μm to 20 μm. Note that after the nitriding treatment, post-treatment processes such as washing and drying may be included. By pulverizing and classifying the particles to the above ranges, optical properties such as light absorption efficiency are improved, and phosphor particles with excellent optical properties can be obtained.

[0101] [Nitride Method] When the phosphor according to the first embodiment is produced by the nitride method, the phosphor raw materials are mixed and the resulting mixture of phosphor raw materials is fired. In particular, to produce the phosphor according to the first embodiment, the conditions may be appropriately set based on the technical concept of dividing the production process into a process for generating crystal nuclei and a process for growing crystals. These methods may be used alone or in combination.

[0102] The manufacturing method of the present invention will be specifically explained below, but by making appropriate adjustments based on the above, the phosphor according to the first embodiment can be obtained.

[0103] Examples of phosphor raw materials include metal compounds and metals. For example, when producing a phosphor having a crystalline phase composition represented by the above formula [1], a raw material for Sr element (hereinafter referred to as "Sr source" as appropriate), a raw material for Ca element (hereinafter referred to as "Ca source" as appropriate), a raw material for Al element (hereinafter referred to as "Al source" as appropriate), a raw material for Si element (hereinafter referred to as "Si source" as appropriate), a raw material for N element (hereinafter referred to as "N source" as appropriate), and a raw material for M element (hereinafter referred to as "M source" as appropriate) are mixed in a required combination (mixing step), the resulting mixture is fired (firing step), and the resulting fired product is crushed, pulverized, and / or washed as necessary (post-treatment step), whereby the phosphor can be produced.

[0104] (Phosphor Raw Material) Known phosphor raw materials can be used. Specific examples of the Eu source among the M sources include Eu ２ O ３ , Eu ２ (SO ４ ) ３ , Eu ２ (C ２ O ４ ) ３ ・10H ２ O, EuF ２ , EuF ３ , EuCl ２ , EuCl ３ , Eu(NO ３ ) ３ ・6H ２ Examples of suitable Eu sources include EuO, EuN, and EuNH. Among these, nitrides, oxides, and halides are preferred, and EuN is more preferred. The purity of the Eu source used is preferably as high as possible, and is generally 98% or higher, and preferably 99% or higher.

[0105] Specific examples of raw materials for other activating elements such as Mn, Ce, Pr, Nd, Sm, Tb, Dy, Ho, Er, Tm, and Yb include compounds in which Eu in each of the compounds given as specific examples of the Eu source is replaced with Mn, Ce, Pr, Nd, Sm, Tb, Dy, Ho, Er, Tm, and Yb, respectively.

[0106] Specific examples of the Sr source include SrO, Sr(OH) ２ ・8H ２O, 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 ３ N ２ , Sr ３ N ４ and SrNH. Among them, SrO, SrCO ３ , Sr ２ N and Sr ３ N ２ is preferred, and Sr ２ N, Sr ３ N ２ is more preferable.

[0107] Specific examples of the Ca source include CaO and Ca(OH). ２ , CaCO ３ , Ca(NO ３ ) ２ ・4H ２ O, CaSO ４ ・2H ２ O, Ca(C ２ O ４ ) H ２ O, Ca (OCOCH ３ ) ２ ・H ２ O, CaF ２ , CaCl ２ , Ca ２ N, Ca ３ N ２ and CaNH. Among them, CaO, CaCO ３ , Ca ２ N and Ca ３ N ２ is preferred.

[0108] A specific example of the Al source is preferably AlN. A specific example of the Si source is SiO. ２ or Si ３ N ４ It is preferable to use SiO２ Specific examples of such compounds include SiO ２ , H ４ SiO ４ and Si(OCOCH ３ ) ４ etc.

[0109] (Mixing step) The phosphor raw materials are weighed so as to obtain a target composition, and are thoroughly mixed using a ball mill or the like to obtain a phosphor raw material mixture (mixing step). The mixing method is not particularly limited, and known methods can be used.

[0110] (Firing Step) Next, the phosphor raw material mixture obtained in the mixing step is fired (firing step). After drying the above-mentioned phosphor raw material mixture as necessary, it is filled into a container such as a crucible and fired using a heating furnace, a pressure furnace, or the like. The firing temperature varies depending on other conditions such as pressure, but the maximum temperature is usually 800°C or higher, preferably 1200°C or higher, more preferably 1500°C or higher, and usually 2200°C or lower, preferably 2100°C or lower, and more preferably 2000°C or lower. By setting the maximum temperature to 800°C or higher, it is possible to prevent the time required for the nitriding treatment from becoming longer. On the other hand, by setting the maximum temperature to 2200°C or lower, it is possible to prevent the generated nitride from volatilizing or decomposing, making it easier to obtain a phosphor having the desired composition. The temperature rise rate is usually 2°C / min or higher, preferably 5°C / min or higher, and usually 30°C / min or lower, preferably 25°C / min or lower.

[0111] The pressure and pressure increase rate during firing can be the same as in the alloy method.

[0112] The firing atmosphere may be any as long as the phosphor according to embodiment 1 can be obtained, but a nitrogen-containing atmosphere is preferred. Furthermore, an atmosphere containing an alkaline earth metal element, such as strontium, is also preferred for obtaining the phosphor according to embodiment 1. The firing time (retention time at the maximum temperature) varies depending on the firing temperature or pressure, but is typically 1 minute or more, preferably 10 minutes or more, more preferably 30 minutes or more, and even more preferably 60 minutes or more. By setting the heating time to 1 minute or more, the nitriding reaction proceeds sufficiently, making it easier to obtain a phosphor with excellent properties. From the perspective of production efficiency, the upper limit of the heating time is typically 24 hours or less, preferably 20 hours or less, more preferably 15 hours or less, and even more preferably 12 hours or less. In a specific embodiment in which the maximum temperature is 1500°C or higher, the heating time is preferably 8 hours or less, more preferably 5 hours or less, and even more preferably 3 hours or less.

[0113] (Post-Treatment Steps) The fired product obtained as described above may be subjected to post-treatment steps such as a classification step, a washing step, or a drying step.

[0114] <Phosphor-containing composition> With regard to embodiments A and B, the phosphor according to embodiment 1 can also be used by mixing with a liquid medium. In particular, when the phosphor according to embodiment 1 is used for applications such as a light-emitting device, it is preferable to use it in a form in which it is dispersed in a liquid medium. A dispersion of the phosphor according to embodiment 1 in a liquid medium may be referred to as the "phosphor-containing composition according to embodiment 1."

[0115] [Phosphor] There is no limitation on the type of phosphor according to embodiment 1 to be contained in the phosphor-containing composition according to embodiment 1, and it can be arbitrarily selected from those described above. Furthermore, the phosphor according to embodiment 1 to be contained in the phosphor-containing composition according to embodiment 1 may be only one type, or two or more types may be used in any combination and ratio. Furthermore, the phosphor-containing composition according to embodiment 1 may contain a phosphor other than the phosphor according to embodiment 1, as long as the effect of the present invention is not significantly impaired.

[0116] [Liquid Medium] The liquid medium used in the phosphor-containing composition according to embodiment 1 is not particularly limited as long as it does not impair the performance of the phosphor within the intended range. For example, any inorganic and / or organic material can be used as long as it exhibits liquid properties under desired use conditions, suitably disperses the phosphor according to embodiment 1, and does not cause undesirable reactions, such as silicone resin, epoxy resin, and polyimide silicone resin.

[0117] [Liquid Medium and Phosphor Content] The contents of the phosphor and liquid medium in the phosphor-containing composition of embodiment 1 may be any as long as they do not significantly impair the effects of the present invention. However, the liquid medium content is typically 50% by mass or more, preferably 75% by mass or more, and typically 99% by mass or less, preferably 95% by mass or less, of the entire phosphor-containing composition of embodiment 1.

[0118] [Other Components] In addition to the phosphor and the liquid medium, other components may be contained in the phosphor-containing composition according to embodiment 1, as long as the effects of the present invention are not significantly impaired. Furthermore, the other components may be used alone, or two or more of them may be used in any combination and ratio.

[0119] <Light-emitting device> With regard to embodiments A and B, in one embodiment, the present invention is a light-emitting device comprising a first light-emitting body and a second light-emitting body that emits visible light when irradiated with light from the first light-emitting body, wherein the second light-emitting body comprises the phosphor according to embodiment 1. The descriptions relating to the phosphor described above can be applied as is to the respective configurations and characteristics of the phosphor according to embodiment 1 that is provided in the light-emitting device of this embodiment. Here, the second light-emitting body may be a single type of phosphor, or two or more types of phosphors may be used in any combination and ratio. Furthermore, the second light-emitting body may contain a phosphor other than the phosphor according to embodiment 1.

[0120] In one embodiment, the light emitting device is a light emitting device in which the second light emitting substance includes at least a red phosphor, and further includes a green phosphor and / or a yellow phosphor, and the red phosphor or the yellow phosphor includes the phosphor according to embodiment 1. In a specific embodiment, the green phosphor and / or the yellow phosphor includes one or more phosphors selected from the group consisting of a garnet-based phosphor, a silicate-based phosphor, a nitride phosphor, and an oxynitride phosphor.

[0121] Specifically, when configuring a light emitting device, the yellow phosphor preferably has an emission peak wavelength in the wavelength range of 550 nm to 600 nm, and the green phosphor preferably has an emission peak wavelength in the wavelength range of 500 nm to 560 nm. Also, the orange to red phosphor has an emission peak wavelength in the wavelength range of usually 615 nm or more, preferably 620 nm or more, more preferably 625 nm or more, and even more preferably 630 nm or more, and usually 660 nm or less, preferably 650 nm or less, more preferably 645 nm or less, and even more preferably 640 nm or less.

[0122] By appropriately combining phosphors in the above wavelength ranges, a light emitting device exhibiting excellent color reproducibility can be provided. Note that the excitation light source may have an emission peak wavelength in a wavelength range of less than 420 nm.

[0123] Hereinafter, several specific embodiments of the light emitting device when the phosphor according to embodiment 1 is used as a yellow phosphor or a red phosphor will be described, but the present embodiment is not limited to these.

[0124] In the above case, the light emitting device of this embodiment can be, for example, in the following form (X), (Y), or (Z). (X) An aspect in which the second illuminant includes at least one kind of yellow phosphor and one or more kinds of red phosphor, and either the yellow phosphor or the red phosphor includes at least the phosphor according to embodiment 1. (Y) An aspect in which the second illuminant includes at least one kind of green phosphor and one or more kinds of red phosphor, and the red phosphor includes at least the phosphor according to embodiment 1. (Z) An aspect in which the second illuminant includes at least one kind of yellow phosphor, one or more kinds of green phosphor, and one or more kinds of red phosphor, and either the yellow phosphor or the red phosphor includes at least the phosphor according to embodiment 1.

[0125] In the above embodiment, the green phosphor and / or the yellow phosphor other than the phosphor according to embodiment 1 may be commercially available, for example, a garnet-based phosphor, a silicate-based phosphor, a nitride phosphor, an oxynitride phosphor, etc. In a specific embodiment, the yellow phosphor and / or the green phosphor includes one or more phosphors selected from the group consisting of a garnet-based phosphor, a silicate-based phosphor, a nitride phosphor, and an oxynitride phosphor.

[0126] (Yellow Phosphor) Examples of garnet-based phosphors that can be used as yellow phosphors other than the phosphor according to the first embodiment include (Y, Gd, Lu, Tb, La) ３ (Al, Ga) ５ O １２ : (Ce, Eu, Nd); as a silicate-based phosphor, for example, (Ba, Sr, Ca, Mg) ２ SiO ４ : (Eu, Ce); nitride phosphors and oxynitride phosphors include, for example, (Ba, Ca, Mg)Si ２ O ２ N ２ : Eu (SiON-based phosphor), (Li, Ca) ２ (Si, Al) １２ (O, N) １６ : (Ce, Eu) (α-sialon phosphor), (Ca, Sr)AlSi ４ (O, N) ７ : (Ce, Eu) (1147 phosphor), (La, Ca, Y, Gd)３ (Al, Si) ６ N １１ :(Ce,Eu)(LSN phosphor), etc. These may be used alone or in combination of two or more.

[0127] Among these, garnet-based phosphors are preferred as yellow phosphors, and Y ３ Al ５ O １２ A YAG-based phosphor represented by the formula:Ce is most preferred.

[0128] (Green Phosphor) Examples of garnet-based phosphors that can be used as the green phosphor include (Y, Gd, Lu, Tb, La) ３ (Al, Ga) ５ O １２ :(Ce, Eu, Nd), Ca ３ (Sc, Mg) ２ Si ３ O １２ : (Ce, Eu) (CSMS phosphor); silicate-based phosphors include, for example, (Ba, Sr, Ca, Mg) ３ SiO １０ : (Eu, Ce), (Ba, Sr, Ca, Mg) ２ SiO ４ : (Ce, Eu) (BSS phosphor); oxide phosphors include, for example, (Ca, Sr, Ba, Mg) (Sc, Zn) ２ O ４ : (Ce, Eu) (CASO phosphor); nitride phosphors and oxynitride phosphors include, for example, (Ba, Sr, Ca, Mg)Si ２ O ２ N ２ : (Eu, Ce), Si ６－ｚ Al ｚ O ｚ N ８－ｚ : (Eu, Ce) (β-sialon phosphor) (0 < z ≦ 1), (Ba, Sr, Ca, Mg, La) ３ (Si, Al) ６ O １２ N ２ : (Eu, Ce) (BSON phosphor), (La, Ca, Y, Gd) ３ (Al, Si) ６ N １１:(Ce,Eu)(LSN phosphor), etc. These may be used alone or in combination of two or more.

[0129] (Red Phosphor) As a phosphor that can be used as a red phosphor other than the phosphor according to the first embodiment, other orange or red phosphors such as garnet-based phosphors, sulfide phosphors, nanoparticle or quantum dot phosphors, nitride phosphors, and oxynitride phosphors can be used. As other orange or red phosphors, for example, the following phosphors can be used. As sulfide phosphors, for example, (Sr,Ca)S:Eu (CAS phosphor) and La2O2S:Eu (LOS phosphor); as garnet-based phosphors, for example, (Y,Lu,Gd,Tb) ３ Mg ２ AlSi ２ O １２ As nanoparticles or quantum dots, for example, phosphors made of a combination of II-VI, III-V, and IV-VI group metals, such as CdSe; as nitride or oxynitride phosphors, for example, (Sr,Ca)AlSiN ３ : Eu (S / CASN phosphor), (CaAlSiN ３ ) １－ｘ (SiO ２ N ２ ) x: Eu (CASON phosphor), (La, Ca) ３ (Al, Si) ６ N １１ : Eu (LSN phosphor), (Ca, Sr, Ba) ２ Si ５ (N, O) ８ : Eu (258 phosphor), (Sr, Ca) Al １＋ｘ Si ４－ｘ O ｘ N ７－ｘ : Eu (1147 phosphor), Mx (Si, Al) １２ (O, N) １６ : Eu (M is Ca, Sr, etc.) (α-sialon phosphor), Li(Sr,Ba)Al ３ N ４ :Eu (wherein x is 0<x<1 in all cases). These may be used alone or in combination of two or more.

[0130] [Configuration of the light-emitting device] The light-emitting device according to this embodiment has a first light-emitting body (excitation light source), and can use at least the phosphor according to the first embodiment as the second light-emitting body. The configuration is not limited, and any known device configuration can be used.

[0131] The first light emitter may be an LED element having a light emitting structure formed of various semiconductors such as a GaN-based semiconductor, a ZnO-based semiconductor, or a SiC-based semiconductor.

[0132] Examples of device configurations and light-emitting device embodiments include those described in Japanese Patent Application Laid-Open No. 2007-291352. Alternatively, the LED element may be fixed to a package such as a bullet-type package or an SMD-type package, or directly fixed to a circuit board, as in the case of a chip-on-board light-emitting device. The form of optical coupling between the LED element and the phosphor is not limited; the space between them may simply be filled with a transparent medium (including air), or an optical element such as a lens, optical fiber, light guide plate, or reflecting mirror may be interposed between them. A structure in which phosphor particles are dispersed in a translucent matrix is ​​typically formed by curing a resin paste in which particulate phosphor is dispersed. In addition to a structure in which an LED element is embedded in the cured paste, various structures are possible, such as a structure in which the cured product covers a portion of the surface of the LED element in a film-like form, or a structure in which a film made of the cured product is disposed at a location separate from the LED element.

[0133] <Uses of Light-Emitting Device> With regard to embodiments A and B, the uses of the light-emitting device according to the present embodiment are not particularly limited, and the device can be used in various fields in which ordinary light-emitting devices are used. However, since the light-emitting device has a wide color reproduction range and high color rendering properties, it is particularly preferably used as a light source for a lighting device or an image display device.

[0134] [Lighting Device] In one embodiment, the present invention may be a lighting device including the light-emitting device as a light source. When the light-emitting device is applied to a lighting device, there are no limitations on the specific configuration of the lighting device, and the light-emitting device as described above may be appropriately incorporated into a known lighting device. For example, a surface-emitting lighting device in which a number of light-emitting devices are arranged on the bottom surface of a holding case may be mentioned.

[0135] [Image Display Device] In one embodiment, the present invention may be an image display device including the light-emitting device as a light source. When the light-emitting device is used as a light source of the image display device, there are no limitations on the specific configuration of the image display device, but it is preferable to use the light-emitting device together with a color filter. For example, when the image display device is a color image display device using a color liquid crystal display element, the image display device can be formed by using the light-emitting device as a backlight and combining it with an optical shutter using liquid crystal and a color filter having red, green, and blue pixels.

[0136] [Vehicle Indicator Light] In one embodiment, the present invention may provide a vehicle indicator light including the light-emitting device as a light source.

[0137] In a specific embodiment, the light-emitting device used in the vehicle indicator lamp is preferably a light-emitting device that emits white light. In the light-emitting device that emits white light, the deviation duv (also referred to as Δuv) of the light color from the blackbody radiation locus is preferably −0.0200 to 0.0200, and the color temperature is preferably 5000 K or more and 30000 K or less.

[0138] In a specific embodiment, the light emitting device used in the vehicle indicator light is preferably a light emitting device that emits red light. In this embodiment, for example, the light emitting device may absorb blue light irradiated from a blue LED chip and emit red light, thereby forming a red light vehicle indicator light.

[0139] Vehicle indicator lights include headlights, side lights, back lights, turn signals, brake lights, fog lights, and other lighting provided on a vehicle for the purpose of providing some kind of indication to other vehicles, people, etc.

[0140] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to the following examples as long as it does not deviate from the gist of the invention.

[0141] <Measurement Method> [Chromaticity Measurement] The emission spectrum was measured at room temperature (25°C) using a 150 W xenon lamp as an excitation light source and a fluorescence measuring device FP6500 (manufactured by JASCO Corporation) equipped with a multichannel CCD detector C7041 (manufactured by Hamamatsu Photonics Co., Ltd.) as a spectrum measuring device.

[0142] The chromaticity coordinates of the x, y color system (CIE 1931 color system) were calculated as chromaticity coordinates x and y in the XYZ color system defined in JIS Z8701 (1999) using data in the wavelength region of 480 nm to 780 nm of the emission spectrum obtained by the above-mentioned method, using a method in accordance with JIS Z8724 (1997).

[0143] [Internal quantum efficiency measurement] A sample was prepared in which phosphor powder was uniformly encapsulated in a transparent resin at a constant mass fraction, and irradiated with 455 nm excitation light in an LMS-200 integrating sphere (manufactured by Labsphere). The converted light spectral radiant flux was measured using a Solid Lambda spectrometer (manufactured by SpectraCo-op). The internal quantum efficiency was calculated from the measured converted light spectral radiant flux and the previously measured excitation light spectral radiant flux. The phosphor powder used in this measurement was a powder (average particle size 10 to 30 μm) of the phosphor produced in Example 1 or Comparative Example 1 described below.

[0144] [Transmission Electron Microscope Observation] Since the space group of the crystal structure of an oxynitride phosphor cannot be narrowed down by XRD measurement alone (see, for example, R. J. Hill, J. Appl. Cryst. (1992), 25, 589-610), the space group was confirmed by a method of analyzing convergent beam electron diffraction (CBED) patterns from phosphor particles produced in Example 1 or Comparative Example 1 (described later) using a transmission electron microscope (hereinafter sometimes referred to as TEM) (see, for example, Journal of Ceramics Societies in Japan, 117(1) 94-98(2009)). Furthermore, in recent years, it has become possible to directly observe atomic arrangements by analyzing atomic resolution aberration-corrected scanning transmission electron microscope (STEM) images. In light of this, the space group confirmed by TEM-CBED was re-examined using annular bright-field (ABF) STEM and integrated differential phase contrast (iDPC) STEM, and the distribution of stacking faults and crystalline phase B was further clarified.

[0145] Obtaining TEM-CBED patterns from these phosphor particles, or obtaining ABF-STEM and iDPC-STEM images, requires processing the phosphor particles to be suitable for TEM observation. This processing involves four steps: (1) embedding the phosphor particles in resin or supporting them on a thin needle; (2) cross-section processing; (3) confirming the crystal orientation of each particle exposed in the cross section; and (4) obtaining a thin film platelet approximately 100 nm to 10 nm thick with a surface parallel to the (100) plane, assuming the sample has a CASN crystal structure. There are several methods for step (1), including embedding multiple particles in epoxy resin or adhering a single particle to the tip of a 1 μm-thick tungsten needle using epoxy resin. The inventors used both methods. Steps (2) through (4) are described in detail below, along with the equipment used. (2) Using a JEOL Ltd. SM-09010 (product name: Cross-Section Polisher), argon ion processing was performed at an acceleration voltage of 5.00 kV. (3) The crystal orientation of the particle cross section was confirmed using a JEOL Ltd. JSM-7000F field emission scanning electron microscope (FE-SEM) equipped with a TSL Solutions Inc. OIM crystal orientation analyzer (Electron Back Scattering Diffraction: EBSD). At that time, the electron beam acceleration voltage was adjusted to 20 kV. (4) From the information obtained in (3), particles close to the (100) plane, assuming that the sample has a CASN crystal structure, were identified, and thin film platelets with a thickness of approximately 100 nm to 10 nm and a surface parallel to the (100) plane were obtained using the focused ion beam method (FIB).

[0146] The detailed conditions for the FIB method used are as follows: Sample surface treatment: After forming a carbon film in a high-vacuum deposition device, a tungsten film is formed in an FIB device. (1) Method for preparing test pieces for TEM-CBED observation: The microsampling method was applied. Preparation device: Hitachi, Ltd., focused ion beam processing device FB-2000A. Acceleration voltage: 30 kV, FIB normal processing. Acceleration voltage: 10 kV, FIB thinning processing. (2) Method for preparing test pieces for ABF-STEM observation: The microsampling method was applied. Preparation device: Hitachi High-Tech Fielding Corporation (now Hitachi High-Tech Corporation), Hitachi focused ion / electron beam processing and observation device NB5000. Acceleration voltage: 40 kV, FIB trench processing. Acceleration voltage: 30 kV, FIB chunk rough processing. Acceleration voltage: 20 kV, FIB chunk precision processing. Acceleration voltage: 10 kV. FIB thinning and carbon deposition protective film formation Acceleration voltage: 5 kV FIB finishing (3) Method for preparing specimens for iDPC-STEM observation Dry grinding and dry dispersion methods are used

[0147] The following equipment was used to collect TEM-CBED patterns from the sample: Equipment: Field emission transmission electron microscope TECNAI G2 F20 manufactured by FEI Company Acceleration voltage: 200 kV Observation direction:

[100] (assuming the same crystal structure as CASN) Image recording: CCD camera Measurement temperature: room temperature

[0148] The following equipment was used to collect ABF-STEM images from the sample: Equipment: GrandARM atomic resolution aberration-corrected scanning transmission electron microscope manufactured by JEOL Ltd. Acceleration voltage: 80 kV Observation direction:

[100] (assuming the same crystal structure as CASN) Image recording: ABF detector Measurement temperature: room temperature

[0149] The following equipment was used to collect iDPC-STEM images from the sample: Equipment: Spectra300 manufactured by Thermo Fisher Scientific Inc. Acceleration voltage: 300 kV Observation direction:

[100] (assuming the same crystal structure as CASN) Image recording: Panther STEM detection system Measurement temperature: room temperature

[0150] <Creation of phosphor> (Example 1) Each metal was weighed so that the metal element composition ratio was Al:Si = 1:1 (molar ratio), and the raw material metals were melted in a high-frequency induction melting furnace using a graphite crucible in an argon atmosphere.The molten metal was then poured from the crucible into a mold and solidified, obtaining an alloy (mother alloy) with a metal element composition ratio of Al:Si = 1:1 (molar ratio).

[0151] The master alloy and other raw material metals were weighed so that the metal element composition ratio was Eu:Sr:Ca:Al:Si=0.0068:0.95:0.043:1:1 (molar ratio). －２ After evacuating the furnace to a vacuum of 10 Pa, the evacuation was stopped and the furnace was filled with argon to a predetermined pressure. The master alloy in the calcia crucible was melted in the furnace, and then Sr, Eu, and Ca were added. After confirming that the molten metal containing all the components was being stirred by an induced current, the molten metal was poured from the crucible into a water-cooled copper mold (plate-shaped, 40 mm thick) and solidified.

[0152] The resulting alloy was Sr(Si ０．５ Al ０．５ ) ２ The powder X-ray diffraction pattern was similar to that of the AlB2 type alkaline earth silicide, and the alloy was identified as an intermetallic compound called an AlB2 type alkaline earth silicide. The plate-shaped alloy block was crushed in a nitrogen gas flow to obtain 160 g of alloy powder, and 1.36 g of Eu ２ O ３ The powder mixture obtained by mixing the above was filled into a boron tray and set in a hot isostatic pressing (HIP) apparatus.

[0153] After evacuating the inside of the apparatus to 20 Pa, it was heated to 300 ° C. and continued evacuating at 300 ° C. for 1 hour. After that, the initial temperature and pressure were adjusted so that the nitrogen pressure in the system was 100 MPa at 600 ° C., and then the pressure was increased to 196 MPa at an average pressure increase rate of 8.6 MPa / hr. In addition, in parallel with the pressure increase, the temperature in the system was increased so that the temperature in the system reached 1950 ° C. at the completion of the pressure increase, and the system was maintained at 196 MPa and 1950 ° C. for 2 hours. The temperature and pressure in the system were reduced to room temperature and normal pressure, and the system was pulverized, washed, and dried to obtain the phosphor of Example 1 (SCASN phosphor).

[0154] Comparative Example 1 A CASN phosphor (model number: BR-101 / L) manufactured by Mitsubishi Chemical Corporation was prepared.

[0155] <Evaluation of Phosphors> The selected area diffraction pattern in the

[100] direction was observed for each phosphor using a TEM. The results for Example 1 are shown in Figures 2A and 2B, and the results for Comparative Example 1 are shown in Figure 2C. While slight diffraction indicating the (001) plane was observed in Example 1, no corresponding diffraction was observed in Comparative Example 1.

[0156] Furthermore, each phosphor was observed from the

[100] direction using a TEM, and bright-field images were obtained. The results for Example 1 and Comparative Example 1 are shown in Figures 3A and 3B, respectively. In Comparative Example 1, no stacking faults or subphases corresponding to crystalline phase B were present, and relatively many dislocations and grain boundaries were observed. On the other hand, linear dark areas were observed in Example 1, which indicates that stacking faults parallel to the (002) plane extending in the <010> direction have occurred. From the above, it is considered that Example 1 has significantly reduced residual stress compared to Comparative Example 1. Note that the maximum spacing between stacking faults in Example 1 is 2 μm, and the density of stacking faults in the normal direction is 5 × 10 ３ cm －１ It was.

[0157] A selected area diffraction pattern and a TEM-CBED pattern were collected for the region of the phosphor of Example 1 where no stacking faults existed.

[0158] Figure 4A shows a selected-area diffraction pattern in a circular area with a diameter of 500 nm, and Figure 4B shows a centrally enlarged view of the CBED pattern. The diffraction disks of the intensity distribution appearing in this CBED pattern were examined for symmetry within a single disk or between disks to determine the point group, and the space group Cmc2 １ and Pbcn were identified. In Figure 4A, there is no 001 diffraction reflection specific to Pbcn, and in Figure 4B, a mirror plane showing the symmetry of the orthorhombic crystal structure is observed under conditions parallel to the <002> and <100> directions. In addition, a dark line is observed in the 002 diffraction disk in Figure 4B, suggesting the presence of a two-fold helix axis parallel to the c-axis direction. The TEM-CBED measurements and analysis results of the above examples support the space group candidate P2 suggested by XRD alone. １or Pbcn, but the point group is mm2 and the space group is Cmc2 １ This leads to the conclusion that the crystal structure of

[0159] ABF-STEM images were also collected for regions of the phosphor of Example 1 where no stacking faults existed. The results and enlarged images are shown in Figures 5A and 5B. For a phosphor with the same composition as Example 1, the space group was Cmc2. １ Figure 6A shows a simulated STEM bright-field image of a phosphor having the same composition as in Example 1, but with a space group of Pbcn. Similarly, Figure 6B shows a simulated STEM bright-field image of a phosphor having the same composition as in Example 1, but with a space group of Pbcn. Note that Figures 6A and 6B are images calculated under the conditions of defocus Δf = 4 nm and thickness t = 19.6 nm.

[0160] Furthermore, iDPC-STEM images were collected for the region where no stacking faults existed in the phosphor according to Example 1. The results are shown in Figure 7A. Figure 7B shows an atomic model.

[0161] As is clear from a comparison of FIGS. 5A and 5B, 6A and 6B, and 7A and 7B, the phosphor of Example 1 does not match Pbcn in the region not containing stacking faults, but Cmc2 １ This shows excellent agreement with the perfect crystal.

[0162] Thus, the results of TEM-CBED, ABF-STEM, and iDPC-STEM indicate that the crystal structure in the region without stacking faults is Cmc2 １ In Example 1, the region free of stacking faults was about 5 μm in the <002> direction.

[0163] In Example 1, the region where stacking faults existed was observed limited to the edge of the TEM specimen. １ Since the (001) diffraction reflection, which cannot occur in the Cmc2 １ It was suggested that the stacking fault was displaced in the 1 / 4 <020> direction from the position of

[0164] In other words, in Example 1, the crystalline phase B was observed only at the edge of the TEM specimen. １ Since the (001) diffraction reflection, which cannot occur in the Cmc2 １ It was suggested that the stacking faults were displaced in the 1 / 4 <020> direction from the position of . In this case, the structure of the region where the stacking faults exist corresponds to the structure where sheet B is inserted, as shown in Figures 1B and 1D, and the region exhibits a localized Pbcn structure.

[0165] It is quite possible that the origin of stacking faults is the expansion of dislocations accumulated during molecular plane growth due to their transition to prism planes (changes in the crystal growth plane). The fact that the regions where stacking faults existed were localized in Example 1 suggests that the self-stress inherent in dislocations was relaxed during the molecular plane growth stage in the manufacturing method of the phosphor of Example 1, resulting in localization of the dislocations (also referred to as dislocation recovery or dislocation polygonization). In other words, the structure of the phosphor of Example 1 shows that polygonization of dislocations, which has the effect of relaxing stress, and expansion into stacking faults occurred.

[0166] From the above, the phosphor of Example 1 has Cmc2 as the main phase. １ It can be seen that the region (crystalline phase A) where stacking faults have occurred due to the extension of dislocations can be regarded as a local Pbcn structure, and the diffraction showing the (001) plane, which was slightly observed in Example 1, is thought to be derived from the local Pbcn structure.

[0167] The normalized absorption spectrum and normalized emission spectrum of each phosphor are shown in Figures 8A and 8B, respectively, and the emission peak wavelength and peak half-width are shown in Table 1. As shown in Table 1, compared to the phosphor of Comparative Example 1, the phosphor of Example 1 has a narrower peak half-width and exhibits better emission characteristics.

[0168]

[0169] As described above, both the CASN phosphor of Comparative Example 1 and the SCASN phosphor of Example 1 exhibited Cmc2 １In general, when there are no stacking faults, the crystal structure of the main phase is the same space group as the phosphor central element Eu. ２＋ It is well known that the environment around the ions is also the same, resulting in roughly the same peak half-width. Furthermore, since the phosphor of Example 1 has few dislocations and contains stacking faults, it is believed that the residual stress is reduced compared to the phosphor of Comparative Example 1. Furthermore, the phosphor of this embodiment is thought to exhibit excellent luminescence characteristics due to the localization of stacking faults, possibly as a result of polygonal transformation of dislocations prior to expansion, and to have regions with low strain that appear to be nearly perfect crystals.

[0170] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present invention. Furthermore, the components of the above-described embodiments may be combined in any manner without departing from the spirit of the invention.

[0171] This application is based on Japanese patent applications filed on December 6, 2023 (Patent Application Nos. 2023-206225 and 2023-206226), the contents of which are incorporated by reference into this application.

[0172] The light emitting device according to this embodiment has a wide color reproduction range and high color rendering properties, and therefore can be particularly preferably used as a light source for an illumination device or an image display device.

Claims

1. A phosphor including a crystalline phase having a composition represented by the following formula [1], which includes stacking faults, and the maximum distance between stacking faults in a direction perpendicular to the stacking faults is 50 nm or more. ｘ M.A. １－ｘ MB ｂ M.C. ｃ D ｄ [1] (In the above formula [1], Re includes one or more elements selected from the group consisting of Eu, Mn, Ce, Pr, Nd, Sm, Tb, Dy, Ho, Er, Tm, and Yb; MA includes one or more elements selected from the group consisting of Ca, Sr, Ba, and Mg; MB includes one or more elements selected from the group consisting of Al, B (boron), Ga, In, and Sc; MC includes one or more elements selected from the group consisting of Si, Ge, Ti, and Hf; D is one or more elements selected from the group consisting of N (nitrogen), O (oxygen), F (fluorine), Cl, Br, and I (iodine), and includes at least N (nitrogen); and x, b, c, and d each independently satisfy the following. 0.0<x≦0.2 0.7≦b≦1.3 0.7≦c≦1.3 2.4≦d≦3.6) 2. The phosphor according to claim 1, wherein the maximum distance between stacking faults in a direction perpendicular to the stacking faults is 100 nm or more.

3. The density of the stacking faults in the normal direction is 2×10 ５ cm －１ The phosphor according to claim 1 .

4. The space group of the crystal phase having the composition represented by the formula [1] is Cmc2 １ , Pbcn, P1, P-1, and Cmc2 １ 2. The phosphor according to claim 1, wherein the space group is any one of the space groups belonging to a maximal non-isomorphic subgroup derived from Pbcn and Pbcn.

5. A phosphor comprising a crystalline phase A and a crystalline phase B, wherein the crystalline phase A and the crystalline phase B each have a composition represented by the following formula [1], and the crystalline phase A and the crystalline phase B each have a different space group. ｘ M.A. １－ｘ MB ｂ M.C. ｃ D ｄ [1] (In the above formula [1], Re includes one or more elements selected from the group consisting of Eu, Mn, Ce, Pr, Nd, Sm, Tb, Dy, Ho, Er, Tm, and Yb; MA includes one or more elements selected from the group consisting of Ca, Sr, Ba, and Mg; MB includes one or more elements selected from the group consisting of Al, B (boron), Ga, In, and Sc; MC includes one or more elements selected from the group consisting of Si, Ge, Ti, and Hf; D is one or more elements selected from the group consisting of N (nitrogen), O (oxygen), F (fluorine), Cl, Br, and I (iodine), and includes at least N (nitrogen); and x, b, c, and d each independently satisfy the following. 0.0<x≦0.2 0.7≦b≦1.3 0.7≦c≦1.3 2.4≦d≦3.6) 6. The phosphor according to claim 5, wherein the volume occupancy rate of the crystalline phase A is 60% or more and less than 100% when the sum of the volume occupancy rates of the crystalline phase A and the crystalline phase B is 100%.

7. The space groups of the crystalline phase A and the crystalline phase B having the composition represented by the formula [1] are both Cmc2 １ , Pbcn, P1, P-1, and Cmc2 １ 6. The phosphor according to claim 5, which has a space group belonging to a maximal non-isomorphic subgroup derived from Pbcn and Pbcn.

8. A light emitting device comprising a first light emitting body and a second light emitting body that emits visible light when irradiated with light from the first light emitting body, the second light emitting body including the phosphor according to claim 1 or 5.

9. The light emitting device according to claim 8, wherein the second light emitting body includes at least a red phosphor, and further includes a green phosphor and / or a yellow phosphor, and includes the phosphor according to claim 1 or 5 as the red phosphor or the yellow phosphor.

10. The light emitting device according to claim 9, wherein the green phosphor and / or the yellow phosphor comprises at least one selected from the group consisting of garnet-based phosphors, silicate-based phosphors, nitride phosphors, and oxynitride phosphors.

11. A lighting device comprising the light-emitting device according to claim 8 as a light source.

12. An image display device comprising the light emitting device according to claim 8 as a light source.

13. A vehicle indicator lamp comprising the light emitting device according to claim 8 as a light source.

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