JP2008222988A - Broadband light emitting phosphor, method for producing the same and method for selecting parent material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a guidance for a material design effective in developing a phosphor emitting a broadband fluorescence. <P>SOLUTION: The phosphor emitting a broadband fluorescence is obtained by selecting a crystal having a significant irregularity in a crystal structure and using the crystal as the parent material of phosphor. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a broadband light-emitting phosphor, a method for manufacturing the same, and a method for selecting a host, and relates to the development of a phosphor that can be used for illumination, display media, and the like.

  White fluorescent lamps that are widely used as illumination light sources have a problem of environmental impact due to mercury content. Also, incandescent bulbs have the disadvantages of low energy efficiency and short lifetime. White light emitting diodes, which are becoming popular as display light sources, are being applied to illumination light sources such as automobile head lens light sources and liquid crystal display backlights. However, white light-emitting diodes have the disadvantage of poor color rendering because white light is realized by combining LEDs that emit blue light and phosphors that emit yellow light that is complementary to blue. Yes.

  On the other hand, sunlight with excellent color rendering properties has a broad continuous spectrum with a peak at about 550 nm and reflects black body radiation of about 6000 K. Therefore, development of a white light source for illumination having a broad emission spectrum close to that of sunlight, being environmentally friendly, inexpensive and efficient is demanded. For this purpose, it is necessary to newly develop a phosphor that emits fluorescence in a wavelength region wider than that of the conventional phosphor.

  Some phosphors have a structure in which impurity ions called activators are dispersed in a base crystal. It is known to show various emission spectra corresponding to the diversity of the crystal structure of the host crystal and the concentration and type of activator. Luminescent ionic species as activators are limited to some ions, while host crystals have been reported in large numbers such as phosphates, sulfides, oxides and nitrides. Therefore, the proper selection of the host crystal is the most important for the development of new phosphors. However, at present, there is no clear guideline for selecting a matrix that meets the required performance, such as selecting a parent crystal as a candidate for a parent crystal, such as a compound with a partial substitution of existing compounds or constituent elements of the parent crystal. It has been necessary to introduce various activators into all candidate base crystals to actually produce phosphors, and inefficient research and development have been conducted.

On the other hand, with respect to the development of electronic component materials, a development / selection support system that can efficiently and economically select an optimum material as disclosed in Patent Document 1 is disclosed.
JP2002-350327

    However, the electronic component material development / selection support system disclosed in Patent Document 1 has a problem that the target material is essentially different from the phosphor material and cannot be applied to phosphor development. .

  In addition, to date, there have been few reports that have examined in detail the effects of the crystal structure of the phosphor matrix and the luminescent ion species on the emission spectrum, and if a compound group having any crystal structure is used for the host crystal, There has never been a clear guide for selecting a mother body as to whether a phosphor emitting broadband fluorescence can be obtained. For this reason, it is necessary to investigate the properties of the phosphor matrix in detail for a large number of inorganic and organic compounds, which is extremely inefficient from the viewpoint of time and economy.

  Therefore, the inventors looked promising as a phosphor for white illumination, focusing on the irregularity of the crystal structure, which is a universal property for all compounds, regardless of the chemical composition of the compound and the crystal structure type. The idea was to provide a design guideline for developing a phosphor that emits a broad-band fluorescence.

  The present invention has been made in view of the above-described conventional situation, and provides a method for clearly selecting a phosphor matrix, in which a crystal having a remarkable irregularity in the crystal structure is selected as the matrix of the phosphor. Therefore, it is an issue to be solved to provide a guideline for effective material design in developing a phosphor emitting broadband fluorescence.

  According to the present invention, a phosphor having a broad band of fluorescence can be obtained by selecting a crystal having a remarkable irregularity in the crystal structure and using the crystal as a matrix of the phosphor.

  The invention described in claim 1 is a phosphor and a method for producing the phosphor or a method for selecting the matrix, characterized in that a crystal having a remarkable irregularity in the crystal structure is used as the matrix of the phosphor.

  Crystals generally have irregularities such as point defects, dislocations, polytypes, twins, and domain structures. In the present invention, a crystal having significant irregularity in the crystal structure is a crystal having irregularity due to deviation of the atomic position in the periodic structure from the average position, or a plurality of atoms having different valences or atomic species. It includes crystals that have irregularities by statistically occupying one crystallographic position, or crystals that have both of these two types of irregularities.

  According to the host selection method of the present invention, (1) if the crystal structure is not yet known (unknown structure), the (2) crystal structure is known from the results of crystal structure analysis using the diffraction method. In the case of the above compound, a method for selecting a phosphor matrix for producing a phosphor that emits fluorescence in a broad wavelength range is provided from a literature describing the structural parameters or a crystal structure database.

  Specifically, it is due to irregularity due to deviation of the atomic position in the periodic structure of the crystal from its average position, or a plurality of atoms with different valences or atomic species statistically occupying one crystallographic position. It is to select a group of compounds having irregularity as a matrix of a phosphor that emits light in a wide band.

  In order to apply the method for selecting whether or not the compound has an unknown structure as a host of the broadband light-emitting phosphor according to the present invention, it is first necessary to determine the crystal structure. Recent advances in X-ray diffractometers, analysis software, and computing speed of personal computers have made it possible to analyze crystal structures with significant irregularities in a short time.

  An example of the procedure for determining the crystal structure of an unknown structural compound is as follows. First, a powder sample of an unknown structural compound is prepared, and profile data is collected with a powder X-ray diffractometer. The diffraction data can be analyzed for crystal structure by using analysis software operating on a personal computer. Specifically, the initial structure model is obtained by the direct method (Non-patent document 1), the structure is refined by the Rietveld method (Non-patent document 2), and the maximum entropy method (Non-patent document 3) and pattern fitting are performed. A method (Non-patent Document 4) is combined to obtain an electron density distribution in which the bias of the crystal structure model is removed as much as possible. If the structural model is inadequate, there are a series of methods to improve it to an atomic position division model or the like as compared with the electron density distribution. However, these are examples of a series of procedures in determining the crystal structure of an unknown structural compound, and a method of growing a single crystal of an unknown structural compound and determining the crystal structure by a single crystal X-ray diffraction method, There is also a method of analyzing the crystal structure by using another method such as neutron diffraction method or electron beam diffraction method in combination or independently.

In addition, by selecting a compound having significant irregularity from a group of compounds whose crystal structure has been clarified, and focusing on them, the synthesis of the phosphor and the fluorescence evaluation are performed, so that the host crystal according to the present invention can be obtained. And the production of a broadband phosphor.
Journal of Applied Crystallography, Vol. 32, 339 (1999) Journal of Applied Crystallography, Vol. 2, 65 (1969) Zeitschrift fuer Kristallographie, Vol. 216, 71 (2001) Materials Science Forum, Vol. 378-381, 59 (2001) Crystals contain irregularities such as chemical defects such as point defects, dislocations, polytypes, twins, domain structures, and solid solutions. Crystals with remarkable irregularity include α-AgI (Non-patent Document 5) exhibiting superionic conductivity and LiMn2O4 (Non-patent Document 6) which is attracting attention as a positive electrode material for lithium ion secondary batteries. Specific physical properties may be manifested by significant irregularities in the structure.

Although the theoretical elucidation from the viewpoint of crystal chemistry and spectroscopy has not been achieved at present, the inventors have made a broad wavelength region by using a group of compounds having a remarkably irregular structure as a host of the phosphor. The inventors have found that a phosphor emitting fluorescence is obtained, and have come to the inventions according to claims 1 to 15.
Journal of the Crystallographic Society of Japan, Vol. 48, No. 1, 30 (2006) Journal of the Crystallographic Society of Japan, Vol. 48, No. 1, 17 (2006)

  To date, there have been few reports that have examined in detail the effects of the crystal structure of the phosphor matrix and the luminescent ion species on the emission spectrum. There has never been a clear guideline for selecting a mother as to whether a fluorescent material emitting fluorescence can be obtained. For this reason, it is necessary to investigate the properties of the phosphor matrix in detail for a large number of inorganic and organic compounds, which is extremely inefficient from the viewpoint of time and economy.

Therefore, the inventors are promising as a phosphor for white illumination, focusing on the irregularity of the crystal structure, which is a universal characteristic for all compounds, regardless of the chemical composition and crystal structure type of the compound. The idea was to provide design guidelines for developing phosphors that emit broadband fluorescence.
Some phosphors have a structure in which impurity ions called activators are dispersed in a base crystal. The luminescent ion species as the activator is limited to some ions such as rare earth, while the base crystal can be diverted to different applications by changing the concentration and type of the activator. Therefore, the phosphor matrix or phosphor provided by claims 1 to 16 is not a phosphor limited to the luminescent ion species and concentration used in this example, but an element that can generate a luminescence center. If it is, this can be used as an activator, without being restricted by the luminescent ion species or its concentration. Furthermore, the phosphor matrix or phosphor provided by claims 1 to 16 is not a light emitting material limited to ultraviolet excitation with a wavelength of 200 nm to 400 nm, but excitation of vacuum ultraviolet light, electron beam, electric field, etc. It can be used as a display medium that emits light or a phosphor for illumination, and can be applied to liquid crystal displays, plasma displays, field emission displays, full-color fluorescent display tubes, electroluminescence, and the like. Furthermore, it is inexpensive and does not use volatile components or components harmful to the environment or human body, and can be easily mass-produced.

  Examples of the present invention (Examples 1 to 4) will be described below in detail with reference to the drawings and tables. In the examples, specific compounds having a remarkable irregularity in the crystal structure are selected as the matrix of the phosphor. However, these are only examples, and any compound having a significant irregularity in the crystal structure can be used at the present time. It goes without saying that the present invention can be realized even if a group of compounds not used as a matrix or an unknown group of compounds is replaced with these matrixes and selected as the matrix of the phosphor.

In this example, a method for producing a phosphor based on calcium zirconium aluminate Ca ₇ ZrAl ₆ O ₁₈ as a crystal having significant irregularity in the crystal structure, and the background to the selection as the host will be described. The crystal structure of the host crystal was determined by the present inventors for the first time, and it was revealed for the first time that the atomic position in the periodic structure has irregularity due to deviation from the average position.

Calcium carbonate (CaCO ₃ ), zirconium oxide (ZrO ₂ ), and aluminum oxide (Al ₂ O ₃ ) were used as starting materials and mixed at 7: 1: 3 (molar ratio). This starting material ratio is the ratio at which Ca ₇ ZrAl ₆ O ₁₈ is produced. Next, this mixed powder was uniaxially pressed into pellets with a diameter of about 12 mm and a height of about 3 mm, heated in an electric furnace at 1400 ° C. for 80 hours, then taken out of the electric furnace and cooled. The obtained sample was pulverized into a fine powder. Using a high-resolution X-ray powder diffractometer with CuKα ₁ line (45 kV × 40 mA) as the incident light, the profile intensity in the 2θ range from 10.0012 ° to 148.4958 ° was measured. The number of data points obtained was 16,576, and the time required for the measurement was 29.5 hours.

The X-ray powder diffraction pattern of this compound was orthorhombic and could be indexed, and the values of the lattice constant were a = 1.08549 nm, b = 1.06012 nm, and c = 0.76738 nm. When we investigated the extinction law from the intensity of the diffraction lines, h + l ≠ 2n for h0l reflection, h ≠ 2n for h00 reflection, and l ≠ 2n for 00l reflection disappeared systematically. As shown, Pmn2 ₁ and P2 ₁ nm may be Pmnm. It was determined the crystal structure the direct method for all possible space groups, only promising initial structure model for space group Pmn2 ₁ were obtained. In this initial structure model, there are 21 independent atom positions in the unit cell, and there are three types of Ca atom positions in Wyckoff position 2a (these atom positions are represented by Ca1, Ca2, and Ca3) and Zr atom positions are 1 type, 2 types of Al atom positions (Al1 and Al2), 4 types of O atom positions (O1 and O4, O5, O6), and 2 types of Ca atom positions (Ca4 and Ca5) at Wyckoff position 4b There are 2 types of Al atom positions (Al3 and Al4) and 7 types of O atom positions (O2 and O3, O7, O8, O9, O10, and O11).

The structural parameters of the initial model were refined by the Rietveld method together with the profile parameters. The isotropic atomic displacement (B) parameter at the O atom position is expressed as B (O), assuming that all atom positions are equal. As a result, the B parameter values at the Ca and O atom positions are unusually large (B (Ca1) = 2.3 (2) × 10 ^-2 nm ² and B (Ca2) = 1.6 (2) × 10 ^-2 nm ² , B (Ca3) = 12.8 (6) × 10 ^-2 nm ² , B (Ca4) = 1.7 (1) × 10 ^-2 nm ² , B (Ca5) = 1.7 (1) × 10 ^-2 nm ² , B ( O) = 2.3 (1) × 10 ^-2 nm ² ) and the reliability (R) factor is also relatively large (R _wp = 16.30% (S = R _wp / R _e = 2.08) and R _p = 12.52%, R _B = 10.57%, R _F = 3.66%), which is not a satisfactory crystal structure analysis result.

Therefore, we constructed a crystal structure model with irregularity due to the deviation of the atomic position from the average position for the atomic position that showed an abnormally large B value. In this atomic position division model, each atomic position is divided into two parts (for example, atomic position Ca1 is divided into two parts, Ca1A and Ca1B) with respect to five kinds of Ca atomic positions, and finally 10 kinds of Ca atomic positions are obtained. (Ca1A and Ca1B, Ca2A, Ca2B, Ca3A, Ca3B, Ca4A, Ca4B, Ca5A, Ca5B) are provided. Furthermore, for 11 types of O atoms, the symmetry of 3 types of O atoms at the 2a position (O4 and O5, O6) decreases from 2a to 4b, and 5 types of O atoms at the 4b position (O7 and O8). , O9, O10, O11), each atom position is divided into two to provide 10 kinds of O atom positions (O7A and O7B, O8A, O8B, O9A, O9B, O10A, O10B, O11A, O11B) and the rest The three types of O atom positions (O1, O2, and O3) are left undivided. When the structural parameters of this atomic position splitting model were refined by the Rietveld method, a reasonable B value and a lower R factor value (R _wp = 9.66% (S = 1.23)) for all atomic positions. R _p = 7.20%, R _B = 3.59%, R _F = 2.27%). The crystallographic data of Ca ₇ ZrAl ₆ O ₁₈ , the values of structural parameters, and the atomic position resolution model are shown in Table 1 and Table 2, respectively, and FIG.

From the above, the inventors have shown for the first time that the Ca ₇ ZrAl ₆ O ₁₈ crystal has irregularities due to deviation of all Ca atom positions and some O atom positions from the average position in the periodic structure. confirmed.

Therefore, the inventors have observed that the Ca ₇ ZrAl ₆ O ₁₈ crystal having irregularity due to the deviation of all Ca atom positions and some O atom positions in the periodic structure from the average position of the matrix according to the present invention. In light of the selection method, we obtained a guideline that it is promising as a matrix of a broadband light-emitting phosphor, and attempted to synthesize a phosphor using Bi as an activator.

Using calcium carbonate (CaCO ₃ ), zirconium oxide (ZrO ₂ ), aluminum oxide (Al ₂ O ₃ ), and bismuth oxide (Bi ₂ O ₃ ) as starting materials, mixed at 6.85: 1: 3: 0.05 (molar ratio) did. This starting material ratio is the ratio at which Ca _6.85 Bi _0.10 ZrAl ₆ O ₁₈ is produced. Next, this mixed powder is uniaxially pressed into pellets with a diameter of about 12 mm × height of about 3 mm, heated in an electric furnace at 1050 ° C for about 1 hour, further heated up and heated at 1300 ° C for about 5 hours Went. The sample was removed from the electric furnace, cooled, and pulverized to obtain a fine powder sample. The profile intensity was measured using an X-ray powder diffractometer using CuKα ₁ line (45 kV × 40 mA) as incident light. From the obtained X-ray diffraction pattern, it was confirmed that the synthesized sample had a crystal structure equivalent to Ca ₇ ZrAl ₆ O ₁₈ .

Using a commercially available spectrofluorometer, the fluorescence intensity at a wavelength of 200 nm to 800 nm was measured using excitation light at a wavelength of 200 nm to 400 nm. FIG. 2 shows the results of evaluating the excitation spectrum and emission spectrum of the obtained Ca _6.85 Bi _0.10 ZrAl ₆ O ₁₈ powder sample.

As is apparent from the evaluation results shown in FIG. 2, the obtained Ca _6.85 Bi _0.10 ZrAl ₆ O ₁₈ has an excitation peak wavelength in the ultraviolet region near 320 nm. When the emission spectrum of Ca _6.85 Bi _0.10 ZrAl ₆ O ₁₈ was observed at an excitation wavelength of 320 nm, the fluorescence showed a broad spectrum with a peak of 470 nm, and a broad spectrum ranging from 350 nm to 600 nm. That is, the bismuth activated calcium zirconium aluminate phosphor Ca _6.85 Bi _0.10 ZrAl ₆ O ₁₈ obtained by the above method is a phosphor that emits broadband fluorescence when excited by ultraviolet rays. In addition, mass production can be easily performed by heating in an air atmosphere.

In this example, a method for producing a phosphor based on a barium calcium silicate solid solution (Ba _x Ca _1-x ) ₂ SiO ₄ (0.6 ≦ x ≦ 0.775) as a crystal having significant irregularity in the crystal structure, and the matrix The process that led to the selection will be described.

Non-patent document 7 reports that this base crystal stably exists in a chemical composition range of 0.6 ≦ x ≦ 0.775. The inventors determined for the first time the crystal structure of (Ba _0.65 Ca _0.35 ) ₂ SiO ₄ (x = 0.65), and the (Ba _x Ca _1-x ) ₂ SiO ₄ (0.6 ≦ x ≦ 0.775) crystal has Both irregularities due to deviation of the atomic position in the periodic structure from the average position and irregularities due to statistically occupying one crystallographic position of atoms with different atomic species It was revealed for the first time that it was equipped.

Ind. Ital. Cemento Vol.33, 397 (1963) Barium carbonate (BaCO3), calcium carbonate (CaCO3) and silica (SiO2) were used as starting materials and mixed at 1.3: 0.7: 1 (molar ratio). This starting material ratio is the ratio at which (Ba0.65Ca0.35) 2SiO4 is produced. Next, this mixed powder was uniaxially pressed into pellets with a diameter of about 12 mm and a height of about 3 mm, heated in an electric furnace at 1500 ° C. for 5 hours, then taken out of the electric furnace and cooled. The obtained sample was pulverized into a fine powder. Using a high-resolution X-ray powder diffractometer with CuKα1 ray (45 kV × 40mA) as incident light, the profile intensity in the 2θ range from 17.0032 ° to 148.4958 ° was measured. The number of data points obtained was 15738, and the time required for the measurement was 24.5 hours.

The X-ray powder diffraction pattern of this compound can be indexed with hexagonal unit cells, and the values of lattice constants are a = 0.57554 (5) nm and c = 1.4686 (1) nm. When the extinction law was examined from the intensity of the diffraction lines, no systematic disappearance of reflection was observed. Non-Patent Document 8 reveals that the Laue symmetry of this crystal is -3m, so there is a possibility of P321, P3m1, P-3m1, P312, P31m and P-31m as the space group of this crystal. It was shown that. When crystal structures were obtained by direct methods for all possible space groups, a promising initial structure model was obtained only for space group P-3m. This initial structural model has 11 independent atomic positions in the unit cell. Among them, there are five types of atomic positions assuming that Ba and Ca atoms are present at a ratio of 65% and 35%, respectively, and their Wyckoff positions are 2d (the atomic position is represented by M1), 1a (M2), 2d ( M3), 2c (M4), and 1b (M5). In addition, there are two types of 2d Si atom positions (Si1 and Si2). There are four types of O atom positions, 6i (O1), 2d (O2), 6i (O3), and 2d (O4) positions.

Journal of the American Ceramics Society, Vol.75, 884 (1992) The structural parameters of the initial model were refined by the Rietveld method together with the profile parameters, and the isotropic atomic positions in M1, M2, O1, O2, and O3 The value of the atomic displacement (B) parameter is unusually large (B (M1) = 1.73 (9) x 10-2nm2 and B (M2) = 7.1 (3) x 10-2nm2, B (O1) = 6.3 (3) × 10-2nm2, B (O2) = 11.2 (10) × 10-2nm2, B (O3) = 1.7 (2) × 10-2nm2), and the reliability (R) factor is also relatively large ( Rwp = 11.19% (S = Rwp / Re = 1.74) and Rp = 8.66%, RB = 3.97%, RF = 2.00%), which was not a satisfactory crystal structure analysis result.

  Therefore, with respect to the atomic positions in M1 and M2, O1, O2, and O3 that showed an abnormally large B value, irregularities due to the deviation of these atomic positions from their average positions and five types of atomic positions (M1 And M2, M3, M4, M5) are not equal proportions of Ba and Ca of 65% and 35% respectively, but both irregularities by statistically occupying different proportions at each atomic position. An equipped crystal structure model was constructed.

  For the atomic positions of M1, M2, O1, and O2, the symmetry of the atomic positions was reduced. That is, the symmetry is reduced to 6i at the M1 atom position at the 2d position, the symmetry is reduced to 6g at the M2 atom position at the 1a position, and the symmetry is reduced to 12j at the O1 atom position at the 6i position, In the O2 atom position of 2d position, the symmetry was reduced to 6i. As a result, irregularities due to deviation of the atomic position in the periodic structure from the average position were introduced into the structural model.

  In addition to the above irregularities, in order to introduce irregularities into the crystal structure model by statistically occupying a single crystallographic position of multiple atoms of different atomic species, there are five types of M positions. These structural parameters were set so that the occupancy of Ba atoms and Ca atoms changed.

When the crystal structure model constructed as described above was refined by the Rietveld method, the appropriate B value and lower R factor values (R _wp = 9.64% ( S = 1.50) and R _p = 7.33%, R _B = 3.19%, R _F = 1.44%). The crystallographic data, structural parameter values, and refined crystal structure models of (Ba _0.65 Ca _0.35 ) ₂ SiO ₄ are shown in Table 3, Table 4, and FIG. 3, respectively.

  Table 4 shows that at four types of M positions, M1, M2, M3, and M4, Ba atoms and Ca atoms have irregularities due to statistically occupying these crystallographic positions. That is, the Ba atom and Ca atom occupancy at the M1 atom position are 65.7% and 34.3%, respectively, and the Ba atom and Ca atom occupancy at the M2 atom position are 85.2% and 14.8%, respectively. The occupancy rates of Ba atoms and Ca atoms are 99.2% and 0.8%, respectively, and the occupancy rates of Ba atoms and Ca atoms at the M4 atom position are 2.4% and 97.6%, respectively. The M5 atom position was occupied only by Ba atoms.

From the above, the present inventors have found that the (Ba _0.65 Ca _0.35 ) ₂ SiO ₄ crystal has irregularity due to deviation of part of the Ba atom and Ca atom position and part of the O atom position from the average position in the periodic structure. For the first time, it was shown and confirmed that both Ba atoms and Ca atoms of different atomic species have both irregularities due to statistically occupying one crystallographic position.

Therefore, the present inventors have found that irregularities due to deviation of some of the Ba atom and Ca atom positions and some of the O atom positions from the average position in the periodic structure, and Ba atoms and Ca atoms of different atomic species. (Ba _x Ca _1-x ) ₂ SiO ₄ (0.6 ≦ x ≦ 0.775) crystals with both irregularities due to statistically occupying one crystallographic position are the present invention. In light of the method for selecting a host material based on the above, we obtained a guideline that it is promising as a base material for a broadband light-emitting phosphor, and tried to synthesize a phosphor using Eu as an activator.

Barium carbonate (BaCO ₃ ), calcium carbonate (CaCO ₃ ), silica (SiO ₂ ), and europium oxide (Eu ₂ O ₃ ) were used as starting materials and mixed at 1.3: 0.68: 1: 0.01 (molar ratio). This starting material ratio is the ratio at which (Ba _0.65 Ca _0.34 Eu _0.01 ) ₂ SiO ₄ is formed. Next, this mixed powder was uniaxially pressed into pellets with a diameter of about 12 mm and a height of about 3 mm, heated in air at 1050 ° C for 1 hour, and then heated in a reducing atmosphere at 1400 ° C for 2 hours. The furnace was turned off and cooled to room temperature in the furnace over about 3 hours. The sample was pulverized to obtain a fine powder sample. The profile intensity was measured using an X-ray powder diffractometer using CuKα ₁ line (45 kV × 40 mA) as incident light. From the obtained X-ray diffraction pattern, it was confirmed that the synthesized sample had a crystal structure equivalent to (Ba _0.65 Ca _0.35 ) ₂ SiO ₄ .

Using a commercially available spectrofluorometer, the fluorescence intensity at a wavelength of 200 nm to 800 nm was measured using excitation light at a wavelength of 200 nm to 400 nm. FIG. 4 shows the results of evaluating the excitation spectrum and emission spectrum of the obtained (Ba _0.65 Ca _0.34 Eu _0.01 ) ₂ SiO ₄ powder sample.
As is apparent from the evaluation results shown in FIG. 4, the obtained (Ba _0.65 Ca _0.34 Eu _0.01 ) ₂ SiO ₄ has an excitation peak wavelength in the ultraviolet region near 280 nm. When the emission spectrum of (Ba _0.65 Ca _0.34 Eu _0.01 ) ₂ SiO ₄ was observed at an excitation wavelength of 280 nm, a broad spectrum with a peak of 454 nm was observed for the fluorescence, and a broad spectrum ranging from 400 nm to 620 nm was observed. That is, the europium-activated barium calcium silicate solid solution phosphor (Ba _0.65 Ca _0.34 Eu _0.01 ) ₂ SiO ₄ obtained by the above method is a phosphor that emits broadband fluorescence when excited by ultraviolet rays.

In this example, the production of a phosphor based on calcium strontium phosphate β′-Ca _3-x Sr _x (PO ₄ ) ₂ (1.85 ≦ x ≦ 2.6) as a crystal having significant irregularity in the crystal structure. The method and the background that led to the selection as a parent will be described.

  Non-patent document 9 reports the crystal structure of this parent crystal. According to this, the irregularity due to the deviation of the atomic position in the periodic structure from the average position and a plurality of atoms with different atomic species are one. It has been shown that it has both irregularities due to statistically occupying crystallographic positions.

The inventors have recognized by Non-Patent Document 9 that β′-Ca _3−x Sr _x (PO ₄ ) ₂ (1.85 ≦ x ≦ 2.6) crystal is a compound having a remarkably irregular structure. With the idea that it is promising as a matrix of a light-emitting phosphor, a phosphor synthesis experiment described below was conducted.
Chemistry of Materials, Vol.14, 3197 (2002) According to Non-Patent Document 9, β'-Ca0.71Sr2.29 (PO4) 2 crystal (x = 2.29) has space group belonging to R-3m. The values of the lattice constant are a = 1.07015 (2) nm and c = 1.95787 (2) nm, and there are 11 independent atomic positions in the unit cell. The O atom occupies a crystallographic position of two Wyckoff positions 36i and two Wyckoff positions 18h. Of these, one type of O atom that occupies the Wyckoff position 36i has an occupancy ratio of 1/3, and has irregularity due to deviation of the atomic position in the periodic structure from the average position. In addition, Sr atoms and Ca atoms occupying the Wyckoff position 18h also have irregularities due to deviation of the atomic position in the periodic structure from the average position. In addition to this, three types of Wyckoff positions 18h and one type of Wyckoff position 6c are statistically occupied by Ca atoms and Sr atoms with different atomic species. There are also irregularities due to the statistical occupation of crystallographic positions. That is, β'-Ca0.71Sr2.29 (PO4) 2 crystal is a disorder due to deviation of the O atom and Sr / Ca atom positions in the periodic structure from the average position, and Ca atoms and Sr atoms with different atomic species Has been shown to have both irregularities due to statistical occupancy of one crystallographic position.

  In order to determine the chemical composition range in which β 'phase exists stably, eight types of samples with x values of 1.5, 1.8, 1.9, 2.0, 2.5, 2.6, 2.61, and 2.65 were prepared, and their powder X-ray diffraction was performed. Got a pattern. As a result, it was found that the β ′ phase can be obtained as a single phase when the value of x is in the range of 1.85 ≦ x ≦ 2.6.

Therefore, the inventors have found irregularity due to the deviation of the O atom position from the average position in the periodic structure, and the fact that Ca atoms and Sr atoms of different atomic species statistically occupy one crystallographic position. Β'-Ca _3-x Sr _x (PO ₄ ) ₂ (1.85 ≤ x ≤ 2.6) crystals with both irregularities are emitted in the broadband emission in the light of the host selection method according to the present invention. With the guideline that it is promising as a base material for phosphors, we attempted to synthesize phosphors using Eu as an activator.

Calcium carbonate (CaCO ₃ ) and strontium carbonate (SrCO ₃ ), ammonium dihydrogen phosphate (NH ₄ H ₂ PO ₄ ) and europium oxide (Eu ₂ O ₃ ) are used as starting materials, 1.0: 1.98: 2: 0.01 ( (Molar ratio). This starting material ratio is the ratio at which Ca _1.0 Sr _1.98 Eu _0.02 (PO ₄ ) ₂ is produced. Next, this mixed powder was uniaxially pressed into pellets with a diameter of about 12 mm and a height of about 3 mm, heated in the atmosphere at 400 ° C. for 1 hour, further heated to 1050 ° C. for 1 hour, Heating was performed at 1300 ° C. for 6 hours in a reducing atmosphere, and the electric furnace was turned off and cooled to room temperature in the furnace over about 3 hours.

The obtained sample was pulverized into a fine powder. The profile intensity in the 2θ range from 10.0 ° to 75.0 ° was measured using an X-ray powder diffractometer with CuKα ₁ line (45 kV × 40 mA) as incident light. From the obtained X-ray diffraction pattern, it was confirmed that the synthesized sample had a crystal structure equivalent to β′-Ca _0.71 Sr _2.29 (PO ₄ ) ₂ .

Using a commercially available spectrofluorometer, the fluorescence intensity at a wavelength of 200 nm to 800 nm was measured using excitation light at a wavelength of 200 nm to 400 nm. FIG. 5 shows the results of evaluating the excitation spectrum and emission spectrum of the obtained Ca _1.0 Sr _1.98 Eu _0.02 (PO ₄ ) ₂ powder sample.
As is apparent from the evaluation results shown in FIG. 5, the obtained Ca _1.0 Sr _1.98 Eu _0.02 (PO ₄ ) ₂ has an excitation peak wavelength in the ultraviolet region near 280 nm. When the emission spectrum of Ca _1.0 Sr _1.98 Eu _0.02 (PO ₄ ) ₂ was observed at an excitation wavelength of 280 nm, the fluorescence had a broad spectrum with a peak at 515 nm and became a broad spectrum ranging from 350 nm to 700 nm. It was. That is, the europium activated calcium strontium phosphate phosphor Ca _1.0 Sr _1.98 Eu _0.02 (PO ₄ ) ₂ obtained by the above method is a phosphor that emits broadband fluorescence when excited by ultraviolet rays.

  In this example, as a crystal having a remarkable irregularity in the crystal structure, a method for producing a phosphor based on an alkaline earth rare earth phosphate solid solution crystal having a crystal structure similar to eulite is selected, and the matrix is selected. I will explain the background.

The general formula of the parent crystal is Ca _3-xy M _x Ln _{1 + y} (P _3-y Si _y ) O ₁₂ (where M is at least one element selected from alkaline earth metal elements, Ln is at least one element selected from rare earth elements, x is a number in the range of 0 ≦ x ≦ 3, and y is a number in the range of 0 ≦ y ≦ 0.3. .

According to Non-Patent Document 10, when Ca ₃ Y (PO ₄ ) ₃ having a crystal structure similar to yuritite is rapidly cooled into the water from a temperature of 1215 ° C. or higher, which is the generation temperature range, A single phase of ₃ Y (PO ₄ ) ₃ can be obtained at room temperature. However, if it is taken out from the electric furnace and cooled in the air or cooled relatively slowly, such as by cooling in the electric furnace, Ca ₃ Y (PO ₄ ) ₃ generated at a high temperature becomes Ca _{3 in the} cooling process. It has been shown to decompose into two phases (PO ₄ ) ₂ and YPO ₄ . Therefore, Ca ₃ Y (PO ₄ ) ₃ that decomposes in the cooling process from the generation temperature is unsuitable as a host crystal of the phosphor.

A method such as further Similarly for Ln = calcium other than Y rare earth phosphate _{Ca 3 Ln (PO 4) 3} , turning on the Ca ₃ Ln (PO _{4) 3} produced at a high temperature from the generation temperature range in water Upon rapid cooling, a single phase of Ca ₃ Ln (PO ₄ ) ₃ can be obtained at room temperature. However, when it is taken out from the electric furnace and cooled in the air or cooled relatively slowly, such as by cooling in the electric furnace, Ca ₃ Ln (PO ₄ ) ₃ generated at a high temperature becomes Ca _{3 in the} cooling process. Decomposes into (PO ₄ ) ₂ and LnPO ₄ . Therefore, Ca ₃ Ln (PO ₄ ) ₃ that decomposes in the cooling process from the generation temperature is unsuitable as a host crystal of the phosphor.
Journal of Solid State Chemistry, Vol.179, 3420 (2006) The inventors have partially substituted at least one element selected from alkaline earth metal elements for a part of the Ca atom position of Ca3Y (PO4) 3. Or a method in which a part of the P atom position of Ca3Y (PO4) 3 is partially substituted with Si atoms, or a part of the Ca atom position of Ca3Y (PO4) 3 is selected from alkaline earth metal elements It was found that the decomposition reaction in the cooling process can be suppressed by partial substitution with more than one kind of element and partial substitution of P atom position with Si atom.

For a composition represented by the general formula Ca _3-x Sr _x Y (PO ₄ ) ₃ , in order to determine the chemical composition range in which a single phase of a eulite structure is stably present, the value of x is 0.1. Six types of samples of 0.3, 0.9, 1.5, 2.4, and 3.0 were prepared, and powder X-ray diffraction patterns were obtained. As a result, it has been clarified that a compound having a eulite-type structure can be obtained as a single phase in the entire range where the value of x is 0 ≦ x ≦ 3. That is, Ca ₃ Y (PO ₄ ) ₃ and Sr ₃ Y (PO ₄ ) ₃ form a continuous solid solution. When the same experiment as described above was performed on a composition represented by Ca _3-x Ba _x Y (PO ₄ ) ₃ , Ca ₃ Y (PO ₄ ) ₃ and Ba ₃ Y (PO ₄ ) ₃ became a continuous solid solution. It was clarified that the compound of eulite structure can be obtained as a single phase in the whole range of x value 0 ≦ x ≦ 3.

Next, for the composition represented by the general formula Ca _3-y Y _{1 + y} (P _3-y Si _y ) O ₁₂ , the chemical composition range in which a single phase having a eulite structure is stably present is determined. Therefore, four types of samples having y values of 0.25, 0.27, 0.3, and 0.35 were prepared, and powder X-ray diffraction patterns were obtained. As a result, it has been clarified that a yuritite-type compound can be obtained as a single phase when the value of y is in the range of 0 ≦ y ≦ 0.3.

From the above, the general formula is Ca _3-xy M _x Ln _{1 + y} (P _3-y Si _y ) O ₁₂ (where M is at least one element selected from alkaline earth metal elements, and Ln Is at least one element selected from rare earth elements, x is a number in the range of 0 ≦ x ≦ 3, and y is a number in the range of 0 ≦ y ≦ 0.3. It has been found that the earth rare earth phosphate solid solution does not cause a decomposition reaction even if it is cooled relatively slowly by taking it out of the electric furnace and cooling it in the air or by cooling in the electric furnace.

According to Non-Patent Document 10, it is shown that Ca ₃ Y (PO ₄ ) ₃ rapidly cooled from the generation temperature has irregularities due to the deviation of the O atom position from the average position in the periodic structure. . Therefore, the inventors have the general formula Ca _3-xy M _x Ln _{1 + y} (P _3-y Si _y ) O ₁₂ (where M is at least one element selected from alkaline earth metal elements) Ln is at least one element selected from rare earth elements, x is a number in the range of 0 ≦ x ≦ 3, and y is a number in the range of 0 ≦ y ≦ 0.3. With the idea that these crystals are promising as the base material of the broadband light-emitting phosphor according to the present invention, the crystal structure analysis and phosphor synthesis experiments described below were performed.

In order to confirm that the above alkaline earth rare earth phosphate solid solution crystals have significant irregularities in the crystal structure, Ca _2.7 Sr _0.3 Y (PO ₄ ) ₃ and Ca _2.85 Y _1.15 (P _2.85 Si _0.15 ) The crystal structure analysis of O ₁₂ was performed. The crystal structure of these crystals was determined by the present inventors for the first time, and it was revealed for the first time that the atomic position in the periodic structure has irregularity due to deviation from the average position.

Calcium carbonate (CaCO ₃ ) and strontium carbonate (SrCO ₃ ), yttrium oxide (Y ₂ O ₃ ), ammonium dihydrogen phosphate (NH ₄ H ₂ PO ₄ ) as starting materials for Ca _2.7 Sr _0.3 Y (PO ₄ ) ₃ And mixed at 2.7: 0.3: 1: 3 (molar ratio). This starting material ratio is the ratio at which Ca _2.7 Sr _0.3 Y (PO ₄ ) ₃ is produced. Next, this mixed powder was uniaxially pressed into pellets with a diameter of about 12 mm and a height of about 3 mm, heated in the atmosphere at 400 ° C. for 1 hour, further heated to 1000 ° C. for 1 hour, It was heated at 1400 ° C. for 6 hours, and the electric furnace was turned off and cooled to room temperature in the furnace over about 3 hours. The obtained sample was pulverized into a fine powder. Using a high-resolution X-ray powder diffractometer with CuKα ₁ line (45 kV × 40mA) as incident light, the profile intensity in the 2θ range from 20.00318 to 148.49613 ° was measured. The number of data points obtained was 15739, and the time required for the measurement was 3.25 hours.

The X-ray powder diffraction pattern of this compound was cubic and indexable, and the value of the lattice constant was a = 0.98596 (4) nm. Since the intensity distribution of the X-ray diffraction pattern is very similar to that of eulite (Bi ₄ (SiO ₄ ) ₃ ), the crystal structure of Bi ₄ (SiO ₄ ) ₃ (space group I-43d) was used as the initial structure model. In this initial structure model, there are three independent atom positions in the unit cell, and Wyckoff position 16c has one kind of atom position occupied by all atoms of Ca atom, Sr atom, and Y atom (these atoms And the Wyckoff position 12a has one type of P atom position, and the Wyckoff position 48e has one type of O atom position.

When the structural parameters of the initial model were refined by the Rietveld method together with the profile parameters, the value of the isotropic atomic displacement (B) parameter at the O atom position was abnormally large (B (O) = 12.9 (2) × 10 ^-2 nm ² ) and reliability (R) factor is also relatively large (R _wp = 10.25% (S = R _wp / R _e = 1.52), R _p = 8.28%, R _B = 9.62% , R _F = 8.41%), which is not a satisfactory crystal structure analysis result.

Therefore, we constructed a crystal structure model with irregularities due to the deviation of the atomic position from the average position for the O atomic position that showed an abnormally large B value. In this atomic position division model, one kind of O atom position is divided into two, and finally two kinds of O atom positions (O1 and O2) are provided. When the structural parameters of this atomic position splitting model were refined by the Rietveld method, a reasonable B value and a lower R factor value (R _wp = 9.25% (S = 1.37) were obtained for all atomic positions. R _p = 7.14%, R _B = 6.13%, R _F = 7.77%). Table 5 and Table 6 and Fig. 6 show the crystallographic data of Ca _2.7 Sr _0.3 Y (PO ₄ ) ₃ , the values of structural parameters, and the atomic position resolution model, respectively.

From the above, the inventors have shown and confirmed for the first time that the Ca _2.7 Sr _0.3 Y (PO ₄ ) ₃ crystal has irregularities due to the deviation of the O atom position in the periodic structure from its average position.

Next, in order to confirm that the crystal structure of Ca _2.85 Y _1.15 (P _2.85 Si _0.15 ) O ₁₂ has a remarkable irregularity, the inventors confirmed that the crystal of Ca _2.85 Y _1.15 (P _2.85 Si _0.15 ) O ₁₂ Structural analysis was performed.

Starting materials for Ca _2.85 Y _1.15 (P _2.85 Si _0.15 ) O ₁₂ include calcium carbonate (CaCO ₃ ), yttrium oxide (Y ₂ O ₃ ), ammonium dihydrogen phosphate (NH ₄ H ₂ PO ₄ ), silica (SiO ₂ ) And mixed at 2.85: 1.15: 2.85: 0.15 (molar ratio). This starting material ratio is the ratio at which Ca _2.85 Y _1.15 (P _2.85 Si _0.15 ) O ₁₂ is produced. Next, this mixed powder was uniaxially pressed into pellets with a diameter of about 12 mm and a height of about 3 mm, heated in the atmosphere at 400 ° C. for 1 hour, further heated to 1000 ° C. for 1 hour, It was heated at 1400 ° C. for 6 hours, and the electric furnace was turned off and cooled to room temperature in the furnace over about 3 hours. The obtained sample was pulverized into a fine powder. Using a high-resolution X-ray powder diffractometer with CuKα ₁ line (45 kV × 40 mA) as incident light, the profile intensity in the 2θ range from 10.00536 to 148.49164 ° was measured. The number of data points obtained was 8288, and the time required for the measurement was 3.7 hours.

The X-ray powder diffraction pattern of this compound was cubic and could be indexed, and the value of the lattice constant was a = 0.983283 (5) nm. Since the intensity distribution of the X-ray diffraction pattern is very similar to that of eulite (Bi ₄ (SiO ₄ ) ₃ ), the crystal structure of Bi ₄ (SiO ₄ ) ₃ (space group I-43d) was used as the initial structure model. In this initial structure model, there are three independent atomic positions in the unit cell, and the Wyckoff position 16c has one kind of atomic position that is occupied by all of the Ca, Sr, and Y atoms (these atomic positions). And Wyckoff position 12a has one P atom position, and Wyckoff position 48e has one O atom position.

When we refined the structure parameters of the initial model by the Rietveld method together with the profile parameters, the value of the isotropic atomic displacement (B) parameter at the O atom position is abnormally large (B (O) = 13.3 (2) × 10 ^-2 nm ² ) and reliability (R) factor is also relatively large (R _wp = 9.11% (S = R _wp / R _e = 1.72), R _p = 7.18%, R _B = 8.23% , R _F = 5.01%), the crystal structure analysis result was not satisfactory.

Therefore, we constructed a crystal structure model with irregularities due to the deviation of the atomic position from the average position for the O atomic position that showed an abnormally large B value. In this atomic position division model, one kind of O atom position is divided into two, and finally two kinds of O atom positions (O1 and O2) are provided. When the structural parameters of this atomic position splitting model were refined by the Rietveld method, a reasonable B value and a lower R factor value (R _wp = 7.49% (S = 1.41)) for all atomic positions. R _p = 5.79%, R _B = 3.63%, R _F = 3.93%). The crystallographic data of Ca _2.85 Y _1.15 (P _2.85 Si _0.15 ) O ₁₂ , the values of structural parameters, and the atomic position resolution model are shown in Table 7 and Table 8, respectively, and FIG.

From the above, the inventors have shown and confirmed for the first time that the Ca _2.85 Y _1.15 (P _2.85 Si _0.15 ) O ₁₂ crystal has irregularity due to the O atom position in the periodic structure deviating from its average position. .

From the above, the general formula is Ca _3-xy M _x Ln _{1 + y} (P _3-y Si _y ) O ₁₂ (where M is at least one element selected from alkaline earth metal elements, and Ln Is at least one element selected from rare earth elements, x is a number in the range of 0 ≦ x ≦ 3, and y is a number in the range of 0 ≦ y ≦ 0.3. The earth rare earth phosphate solid solution is taken out from the electric furnace and cooled in the air, or cooled in the electric furnace relatively slowly so that no decomposition reaction occurs, and the periodic structure It has been confirmed that the O atom position in has irregularity due to deviation from its average position.

Therefore, the inventors have expressed the general formula Ca _3-xy M _x Ln _{1 + y} (P _3-y ) where the O atom position in the periodic structure is a crystal having irregularity due to deviation from its average position. Si _y ) O ₁₂ (wherein M is at least one element selected from alkaline earth metal elements, Ln is at least one element selected from rare earth elements, and x is 0 ≦ x ≦ 3 is a number in the range, y is a number in the range of 0 ≦ y ≦ 0.3.) In view of the method for selecting a matrix according to the present invention, an alkaline earth rare earth phosphate solid solution crystal represented by With the guideline that it is promising as a matrix of a broadband light-emitting phosphor, synthesis of a phosphor using Eu as an activator was attempted.

In order to clarify the influence of the concentration of the activator on the emission spectrum, six types of phosphors having different concentrations of the activator were prepared using an alkaline earth rare earth phosphate solid solution as a base. The prepared phosphor has a general formula represented by Ca _3−x Sr _0.3 Eu _x Y (PO ₄ ) ₃ , and the values of x are 0.001, 0.01, 0.025, 0.03, 0.05, and 0.1.

Calcium carbonate (CaCO ₃ ) and strontium carbonate (SrCO ₃ ) as starting materials for Ca _3-x Sr _0.3 Eu _x Y (PO ₄ ) ₃ (where x = 0.001, 0.01, 0.025, 0.03, 0.05, 0.1) Yttrium oxide (Y ₂ O ₃ ), ammonium dihydrogen phosphate (NH ₄ H ₂ PO ₄ ), and europium oxide (Eu ₂ O ₃ ) were used. These are mixed at a predetermined ratio, and the resulting mixed powder is uniaxially pressed into pellets with a diameter of about 12 mm x height of about 3 mm, heated in the atmosphere at 400 ° C for 1 hour, and further heated. After heating at 1000 ° C for 1 hour, it was heated in a reducing atmosphere at 1400 ° C for 6 hours, and the electric furnace was turned off and cooled to room temperature in the furnace over about 3 hours. The sample was pulverized to obtain a fine powder sample. The profile intensity was measured using an X-ray powder diffractometer using CuKα ₁ line (45 kV × 40 mA) as incident light. From the obtained X-ray diffraction patterns, it was confirmed that all the samples obtained by synthesis had a crystal structure equivalent to Ca _2.7 Sr _0.3 Y (PO ₄ ) ₃ .

  Using a commercially available spectrofluorometer, the fluorescence intensity at a wavelength of 200 nm to 800 nm was measured using excitation light at a wavelength of 200 nm to 400 nm.

FIG. 8 shows the results of evaluating the excitation spectrum and emission spectrum of the obtained Ca _2.67 Sr _0.3 Eu _0.03 Y (PO ₄ ) ₃ (x = 0.03) powder sample. As is apparent from the evaluation results shown in FIG. 8, the obtained Ca _2.67 Sr _0.3 Eu _0.03 Y (PO ₄ ) ₃ has an excitation peak wavelength in the ultraviolet region near 280 nm. When the emission spectrum of Ca _2.67 Sr _0.3 Eu _0.03 Y (PO ₄ ) ₃ was observed at an excitation wavelength of 280 nm, the fluorescence showed a broad spectrum with a peak of 450 nm and a broad spectrum ranging from 370 nm to 650 nm. became.

Summarize the results of evaluating the excitation spectrum and emission spectrum of a series of Ca _3-x Sr _0.3 Eu _x Y (PO ₄ ) ₃ (where x = 0.001, 0.01, 0.025, 0.03, 0.05, 0.1) powder samples It is shown in FIG. As is clear from the evaluation results shown in FIG. 9, when the emission spectrum of the obtained Ca _3-x Sr _0.3 Eu _x Y (PO ₄ ) ₃ was observed with ultraviolet light having an excitation wavelength of 280 nm, all emission spectra were broad. Met. Furthermore, as the concentration of Eu as an activator increased from x = 0.001 to x = 0.1, the peak position of the emission spectrum increased uniformly from 444 nm to 492 nm.

That is, the europium-activated alkaline earth rare earth phosphate solid solution phosphor Ca _3-x Sr _0.3 Eu _x Y (PO ₄ ) ₃ obtained by the above method (where x = 0.001, 0.01, 0.025, 0.03, 0.05 , 0.1) is a phosphor that emits broadband fluorescence when excited by ultraviolet rays.

  The phosphor of the present invention can be used for illumination and display media.

FIG. 1 is a view of a crystal structure of Ca ₇ ZrAl ₆ O ₁₈ that is a base crystal of a bismuth-activated calcium zirconium aluminate phosphor according to an embodiment of the present invention, viewed from the c-axis direction. FIG. 2 is a diagram showing an excitation spectrum and an emission spectrum of Ca _6.85 Bi _0.10 ZrAl ₆ O ₁₈ obtained by the method for producing a bismuth-activated calcium zirconium aluminate phosphor according to an embodiment of the present invention. FIG. 3 is a diagram showing a crystal structure of (Ba _0.65 Ca _0.35 ) ₂ SiO ₄ which is a base crystal of a europium activated barium calcium silicate solid solution phosphor according to an embodiment of the present invention. FIG. 4 is a diagram showing an excitation spectrum and an emission spectrum of (Ba _0.65 Ca _0.34 Eu _0.01 ) ₂ SiO ₄ obtained by the method for producing a europium-activated barium calcium silicate solid solution phosphor according to an embodiment of the present invention. . FIG. 5 is a diagram showing an excitation spectrum and an emission spectrum of Ca _1.0 Sr _1.98 Eu _0.02 (PO ₄ ) ₂ obtained by the method for producing a europium-activated calcium strontium phosphate phosphor according to an embodiment of the present invention. is there. FIG. 6 is a view of the crystal structure of Ca _2.7 Sr _0.3 Y (PO ₄ ) ₃ , which is a base crystal of a europium-activated alkaline earth rare earth phosphate solid solution phosphor according to an embodiment of the present invention, viewed from the [001] direction. It is. FIG. 7 is a diagram showing a crystal structure of Ca _2.85 Y _1.15 (P _2.85 Si _0.15 ) O ₁₂ as a base crystal of a europium-activated calcium rare earth phosphate solid solution phosphor according to an embodiment of the present invention viewed from the [001] direction. It is. FIG. 8 shows the excitation spectrum and emission spectrum of Ca _2.67 Sr _0.3 Eu _0.03 Y (PO ₄ ) ₃ obtained by the method for producing a europium-activated alkaline earth rare earth phosphate solid solution phosphor according to one embodiment of the present invention. FIG. FIG. 9 shows a general formula Ca _3-x Sr _0.3 Eu _x Y (PO ₄ ) ₃ (provided by the method for producing a europium-activated alkaline earth rare earth phosphate solid solution phosphor according to an embodiment of the present invention. (x is a number in the range of 0.001 ≦ x ≦ 0.1), and shows the change in the emission spectrum with respect to the Eu concentration.

Claims (16)

1. A phosphor and a method for producing the phosphor, or a method for selecting the matrix, characterized in that a crystal having significant irregularity in crystal structure is used as the matrix of the phosphor. The phosphor includes at least one element selected from rare earth elements and bismuth as an activator, and a method for producing the phosphor or a method for selecting the matrix.   The matrix according to claim 1 or 2, wherein the atomic position in the periodic structure deviates from the average position, and a plurality of atoms having different valences or atomic species statistically represent one crystallographic position. 3. The phosphor according to claim 1 or 2, and a method for producing the phosphor or a method for selecting the matrix thereof, wherein the phosphor has irregularity due to occupancy.   The phosphor according to claim 1 or 2, wherein the matrix according to claim 1 or 2 is a crystal having irregularity due to deviation of an atomic position in the periodic structure from an average position thereof. Method or method of selecting its parent.   The matrix according to claim 1 or 2 is a crystal having irregularity due to a plurality of atoms having different valences or atomic species statistically occupying one crystallographic position. Item 3. The phosphor according to Item 1 or 2, and a method for producing the phosphor or a method for selecting the host. The phosphor according to any one of claims 1 to 5, wherein the matrix according to any one of claims 1 to 5 is represented by a chemical formula Ca ₇ ZrAl ₆ O ₁₈ and a method for producing the phosphor. The phosphor according to any one of claims 1 to 6, wherein the base material according to claim 6 contains Bi as an activator. The matrix according to any one of claims 1 to 5 is represented by a general formula (Ba _x Ca _1-x ) ₂ SiO ₄ (where x is a number in a range of 0.6 ≦ x ≦ 0.775). The phosphor according to any one of claims 1 to 5 and a method for producing the same. The phosphor of any one of claims 1 to 5 or 8, wherein the base material of claim 8 contains Eu as an activator. The matrix according to any one of claims 1 to 5 is represented by a general formula Ca _3-x Sr _x (PO ₄ ) ₂ (where x is a number in the range of 1.85 ≦ x ≦ 2.6). The phosphor according to any one of claims 1 to 5 and a method for producing the same. The phosphor according to any one of claims 1 to 5 or 10, wherein the base material according to claim 10 contains Eu as an activator. At least one matrix according to claims 1 to 5, the general formula _{Ca 3-xy M x Ln 1} + y (P 3-y Si y) O 12 ( where, M is the selected from alkaline earth metal elements Ln is at least one element selected from Sc, Y and rare earth elements, x is a number in the range of 0 ≦ x ≦ 3, and y is in the range of 0 ≦ y ≦ 0.3 The phosphor according to any one of claims 1 to 5, and a method for manufacturing the same. The phosphor according to any one of claims 1 to 5 or 12, wherein the base material of claim 12 contains Eu as an activator. Mother of claim 12 or 13, the general formula _{Ca 3-x M x Ln (} PO 4) 3 ( where, M is at least one element selected from Sr and Ba, Ln is Sc, 14. Y or at least one element selected from rare earth elements, and x is a number in the range of 0 ≦ x ≦ 3). The phosphor according to any one of the above and a method for producing the same. The phosphor according to any one of claims 1 to 5 or 12 to 14, wherein the base material according to any one of claims 12 to 14 contains Eu as an activator. The phosphor according to any one of claims 12 to 15, wherein the phosphor is represented by the general formula Ca _3-xy Sr _x Eu _y Y (PO ₄ ) ₃ (where x is a number in the range of 0 ≦ x ≦ 3, and y is 0.001 ≦ y The phosphor according to any one of claims 1 to 5 and 12 to 15, and a method for producing the same.