Phosphor, method for manufacturing same, light-emitting device, image display device, pigment, and ultraviolet absorber

Abstract

Provided is a phosphor having a high emission intensity even if combined with an LED of less than 450 nm, a method for manufacturing the same, and a light-emitting device, image display device, pigment, and an ultraviolet absorber using the same.　The phosphor according to the present invention includes: an inorganic crystal having the same crystal structure as a crystal represented by Ba2Li1Al1Si2O8, the organic crystal including a Li element, an A element, a D element, an E element, and an X element (where A is at least one kind of element selected from the group consisting of Mg, Ca, Sr, and Ba, D is at least one kind of element selected from the group consisting of Si, Ge, Sn, Ti, and Zr, E is at least one kind of element selected from the group consisting of B, Al, Ga, In, and Sc, and X is an element including at least O); or an inorganic compound in which an M element (where M is at least one kind of element selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, and Yb) is dissolved in this solid-solution crystal.

Description

Phosphors, methods for producing the same, light-emitting devices, image display devices, pigments, and ultraviolet absorbers

[0001] This invention relates to a phosphor mainly composed of an inorganic compound, a method for producing the same, a light-emitting device, an image display device, a pigment, and an ultraviolet absorber.

[0002] Phosphors are used in fluorescent display tubes (VFDs (Vacuum-Fluorescent Displays)), field emission displays (FEDs (Field Emission Displays) or SEDs (Surface-Conduction Electron-Emitter Displays)), plasma display panels (PDPs (Plasma Display Panels)), cathode ray tubes (CRTs (Cathode-Ray Tubes)), liquid crystal display backlights (Liquid-Crystal Display Backlights), white light-emitting diodes (LEDs (Light-Emitting Diodes)), and other applications. In all of these applications, in order for a phosphor to emit light, it is necessary to supply energy to the phosphor to excite it. The phosphor is excited by an excitation source with high energy, such as vacuum ultraviolet light, ultraviolet light, electron beams, or blue light, and emits visible light such as blue light, green light, yellow light, orange light, or red light.

[0003] In recent years, phosphors such as sialon phosphors, oxynitride phosphors, and nitride phosphors have been proposed as phosphors that exhibit less brightness reduction even when excited with high energy.

[0004] An example of this SiAlON phosphor is manufactured by the following general manufacturing process. First, silicon nitride (Si ３ N ４ ), aluminum nitride (AlN), europium oxide (Eu ２ O ３ The mixture is prepared by mixing the following in a predetermined molar ratio and firing it by a hot press method, holding it at a temperature of 1700°C for 1 hour in nitrogen at 1 atmosphere (0.1 MPa) (see, for example, Patent Document 1). The Eu obtained in this process ２＋It has been reported that α-sialon activated with ions becomes a phosphor that is excited by blue light with a wavelength of 450 to 500 nm and emits yellow light with a wavelength of 550 to 600 nm. It is also known that the emission wavelength changes by changing the ratio of Si and Al or the ratio of oxygen and nitrogen while maintaining the crystal structure of α-sialon (see, for example, Patent Document 2 and Patent Document 3).

[0005] As another example of a sialon phosphor, a green phosphor activated with Eu in β-type sialon is known (see Patent Document 4). In this phosphor, it is known that the emission wavelength changes to a shorter wavelength by changing the oxygen content while maintaining the crystal structure (see, for example, Patent Document 5). It is also known that when β-type sialon is activated with Ce ２＋ it becomes a blue phosphor (see, for example, Patent Document 6). ３＋

[0006] An example of an oxynitride phosphor is a blue phosphor (see Patent Document 7) activated with Ce using the JEM phase (LaAl(Si ６－ｚ Al ｚ )N １０－ｚ O ｚ ) as a host crystal. In this phosphor, it is known that by substituting a part of La with Ca while maintaining the crystal structure, the excitation wavelength and the emission wavelength both become longer wavelengths.

[0007] As another example of an oxynitride phosphor, a blue phosphor (see Patent Document 8) activated with Ce using a La-N crystal La ３ Si ８ N １１ O ４ as a host crystal is known.

[0008] An example of a nitride phosphor is a red phosphor (see Patent Document 9) activated with Eu using CaAlSiN ３ as a host crystal. By using this phosphor, there is an effect of improving the color rendering property of a white LED. A phosphor added with Ce as an optically active element has been reported to be an orange phosphor. ２＋

[0009] ​​Thus, the emission color of a phosphor is determined by the combination of the parent crystal and the metal ions (activating ions) dissolved in it. Furthermore, the combination of the parent crystal and the activating ions determines the emission characteristics such as the emission spectrum and excitation spectrum, as well as the chemical stability and thermal stability. Therefore, if the parent crystal or the activating ions are different, they are considered different phosphors. Also, even if the chemical composition is the same, materials with different crystal structures will have different emission characteristics and stability due to the difference in the parent crystal, and are therefore considered different phosphors.

[0010] Furthermore, in many phosphors, it is possible to substitute the types of constituent elements while maintaining the crystal structure of the parent crystal, thereby changing the emission color. For example, a phosphor with Ce added to a YAG crystal emits green light, but a phosphor in which some of the Y in the YAG crystal is replaced with Gd and some of the Al is replaced with Ga exhibits yellow light. Furthermore, CaAlSiN ３ In phosphors to which Eu is added, it is known that substituting a portion of Ca with Sr changes the composition while maintaining the crystal structure, resulting in a shorter emission wavelength. Phosphors in which elemental substitution is performed while maintaining the crystal structure are considered to belong to the same group of materials.

[0011] Therefore, in the development of novel phosphors, it is important to find a host crystal with a novel crystal structure. By activating metal ions responsible for luminescence in such a host crystal to induce fluorescent properties, it is possible to propose novel phosphors.

[0012] Specification of Japanese Patent No. 3668770 Specification of Japanese Patent No. 3837551 Specification of Japanese Patent No. 4524368 Specification of Japanese Patent No. 3921545 Specification of Japanese Patent Publication No. 2007 / 066733 Japanese Patent Publication No. 2006 / 101096 Japanese Patent Publication No. 2005 / 019376 Japanese Patent Publication No. 2005-112922 Japanese Patent Publication No. 3837588 Specification

[0013] The present invention aims to meet such demands, and one of its objectives is to provide a phosphor that has different luminescence characteristics (luminescence color, excitation characteristics, and emission spectrum) than conventional phosphors, and that has high luminescence intensity even when combined with LEDs of less than 450 nm, as well as a method for manufacturing the same, a light-emitting device using the same, an image display device, a pigment, and an ultraviolet absorber.

[0014] The phosphor of the present invention contains Li, A, D, E, and X (wherein A is at least one element selected from the group consisting of Mg, Ca, Sr, and Ba; D is at least one element selected from the group consisting of Si, Ge, Sn, Ti, and Zr; E is at least one element selected from the group consisting of B, Al, Ga, In, and Sc; and X is an element containing at least O), and Ba ２ Li １ Al １ Si ２ O ８ The present invention provides an inorganic crystal having the same crystal structure as the crystal shown, or an inorganic compound in which element M (where M is at least one element selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, and Yb) is solid-dissolved in this solid solution crystal, thereby solving the above problem. ２ Li １ Al １ Si ２ O ８ An inorganic crystal having the same crystal structure as the crystal shown may be an orthorhombic crystal. ２ Li １ Al １ Si ２ O ８ Inorganic crystals having the same crystal structure as the crystal shown are in the space group Pna2 １The inorganic compound has the following symmetry, and the lattice constants a, b, and c may be in the range of a = 0.80608 ± 0.05 nm, b = 1.90798 ± 0.05 nm, and c = 0.50279 ± 0.05 nm. Element A may contain at least Ba, element D may contain at least Si, and element E may contain at least Al. Element X may further contain at least one element selected from the group consisting of N and F. Element M may contain at least Eu. The inorganic compound has the compositional formula M ｄ A ｅ Li ｆ D ｇ E ｈ X ｉ (wherein the formula d+e+f+g+h+i=1, M is an element selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, and Yb, A is an element selected from the group consisting of Mg, Ca, Sr, and Ba, D is an element selected from the group consisting of Si, Ge, Sn, Ti, and Zr, E is an element selected from the group consisting of B, Al, Ga, In, and Sc, and X is an element containing at least O), and the parameters d, e, f, g, h, and i may be expressed as compositions within the range satisfying the following conditions: 0.00001≦d≦0.05 0.08≦e≦0.2 0.03≦f≦0.1 0.08≦g≦0.2 0.01≦h≦0.15 0.45≦i≦0.65. The parameters d, e, f, g, h, and i may satisfy the following conditions: 0.0001 ≤ d ≤ 0.02, 0.1 ≤ e ≤ 0.18, 0.05 ≤ f ≤ 0.09, 0.1 ≤ g ≤ 0.2, 0.02 ≤ h ≤ 0.12, and 0.5 ≤ i ≤ 0.62. By irradiating with an excitation source, fluorescence with a peak in the wavelength range of 450 nm to 540 nm may be emitted. The excitation source may be vacuum ultraviolet light, ultraviolet light or visible light, electron beams or X-rays having a wavelength of 100 nm to less than 450 nm. ２ Li １ Al １ Si ２ O ８An inorganic crystal having the same crystal structure as the crystal shown may be solid-dissolved in Eu, and when irradiated with light of 280 nm to 400 nm, it may emit fluorescence with an emission peak wavelength in the range of 480 nm to 500 nm. The color emitted when the excitation source is irradiated may satisfy the conditions 0 ≤ x ≤ 0.25 and 0.3 ≤ y ≤ 0.5 in the (x, y) values ​​on the CIE 1931 chromaticity coordinate system. The inorganic compound is Ba ２－ｐ Eu ｐ Li １＋ｑ Al １＋ｒ Si ２－ｒ O ８－ｓ X' ｓ(wherein X' is N and / or F, and the parameters p, q, r, and s satisfy 0 < p ≤ 0.2, -0.15 ≤ q ≤ 0.15, -1 ≤ r ≤ 1, and 0 ≤ s ≤ 1, respectively.) The method for producing the phosphor according to the present invention comprises firing a mixture of a metal compound containing element M, element Li, element A, element D, element E, and optionally element X (wherein M is at least one element selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, and Yb; A is at least one element selected from the group consisting of Mg, Ca, Sr, and Ba; D is at least one element selected from the group consisting of Si, Ge, Sn, Ti, and Zr; E is at least one element selected from the group consisting of B, Al, Ga, In, and Sc; and X is an element containing at least O) in a temperature range of 1000°C to 1200°C, thereby solving the above problem. The light-emitting device according to the present invention comprises at least a light-emitting light source and a phosphor, the phosphor includes the above-mentioned phosphor, thereby solving the above problem. The light-emitting source may be a light-emitting diode (LED), laser diode (LD), semiconductor laser, or organic electroluminescent light-emitting element (OLED) that emits light with a wavelength of 330 nm to 420 nm. The light-emitting device may be a white light-emitting diode, a lighting fixture including a plurality of the white light-emitting diodes, a vehicle indicator light, or a backlight for a liquid crystal panel. The image display device according to the present invention comprises at least an excitation source and a phosphor, the phosphor includes the above-mentioned phosphor, and thereby solves the above problem. The pigment according to the present invention consists of the above-mentioned phosphor, and thereby solves the above problem. The ultraviolet absorber according to the present invention consists of the above-mentioned phosphor, and thereby solves the above problem.

[0015] The phosphor of the present invention is Ba ２ Li １ Al １ Si ２ O ８The present invention primarily contains an inorganic crystal having the same crystal structure as the crystal shown, or an inorganic compound in which activating ions are solid-dissolved in this solid solution crystal. As a result, it exhibits high-brightness luminescence and is excellent as a phosphor that emits blue to green light at certain compositions. The phosphor of the present invention provides a useful phosphor that is suitably used in light-emitting devices, lighting fixtures, vehicle indicator lights for automatic driving, backlight sources for liquid crystals, VFDs, FEDs, PDPs, CRTs, etc. Furthermore, since this phosphor absorbs ultraviolet light, it is suitable as a pigment and an ultraviolet absorber.

[0016] Ba ２ Li １ Al １ Si ２ O ８ :Eu ２＋ Figure Ba shows the crystal structure of the crystal. ２ Li １ Al １ Si ２ O ８ CuKα calculated from the crystal structure of the crystal １ Figure 1 shows the appearance of the composite in Example 1, which is shown using powder X-ray diffraction. Figure 7 shows the excitation and emission spectra of the composite in Example 7. Schematic diagram showing a lighting fixture (bullet-shaped LED lighting fixture) according to the present invention. Schematic diagram showing a lighting fixture (substrate-mounted LED lighting fixture) according to the present invention. Schematic diagram showing an image display device (plasma display panel) according to the present invention. Schematic diagram showing an image display device (field emission display panel) according to the present invention.

[0017] The phosphor of the present invention will be described in detail below with reference to the drawings.

[0018] The phosphor of the present invention contains Li, A, D, E, and X (wherein A is at least one element selected from the group consisting of Mg, Ca, Sr, and Ba; D is at least one element selected from the group consisting of Si, Ge, Sn, Ti, and Zr; E is at least one element selected from the group consisting of B, Al, Ga, In, and Sc; and X is an element containing at least O), and Ba ２ Li １ Al １ Si ２ O８ An inorganic crystal having the same crystal structure as the crystal shown in ８ , or an inorganic compound in which an M element (where M is one or more elements selected from Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, and Yb) is dissolved in this solid solution crystal, functions as a high-brightness phosphor by being contained as a main component.

[0019] In this specification, Ba ２ Li １ Al １ Si ２ O ８ An inorganic crystal having the same crystal structure as the crystal shown in ８ , or this solid solution crystal is collectively referred to as, for simplicity, Ba ２ Li １ Al １ Si ２ O ８ system crystal. The inorganic crystal having the same crystal structure as the crystal shown in ８ also includes the crystal shown in ８ . ２ Li １ Al １ Si ２ O ８ The inorganic crystal having the same crystal structure as the crystal shown in ８ includes the crystal shown in ８ . ２ Li １ Al １ Si ２ O ８ shown.

[0020] Ba ２ Li １ Al １ Si ２ O ８ shown is a crystal newly synthesized by the present inventor and confirmed to be a new crystal by crystal structure analysis, and has not been reported prior to the present invention.

[0021] FIG. 1 is a diagram showing the crystal structure of the Ba ２ Li １ Al １ Si ２ O ８ : Eu ２＋ crystal.

[0022] The Ba ２ Li １ Al １ Si ２ O ８ : Eu２＋ According to single-crystal structure analysis performed on the crystal, Ba ２ Li １ Al １ Si ２ O ８ :Eu ２＋ The crystal belongs to the orthorhombic system, Pna2 １ It belongs to the 33rd space group (International Tables for Crystallography) and occupies the crystal parameters and atomic coordinate positions shown in Table 1.

[0023] In Table 1, the lattice constants a, b, and c represent the lengths of the unit cell axes, and α, β, and γ represent the angles between the unit cell axes. Atomic coordinates represent the position of each atom in the unit cell as a value between 0 and 1, with the unit cell as the unit. This crystal contains the atoms of Ba, Li, Al, Si, O, and Eu. Analysis results showed that Ba and Eu exist in two types of positions (Ba, Eu(1)) and (Ba, Eu(2)) without distinguishing between them. Analysis results showed that Si exists in two types of positions (Si(1)) and (Si(2)). Analysis results showed that Al exists in one type of position, Al(1). Analysis results showed that O exists in eight types of positions, O(1) to O(8). Analysis results showed that Li exists in one type of position, Li(1).

[0024]

[0025] Figure 1 shows Ba ２ Li １ Al １ Si ２ O ８ :Eu ２＋ This is a diagram showing the crystal structure of the crystal.

[0026] Analysis using the data in Table 1 showed that Ba ２ Li １ Al １ Si ２ O ８ :Eu ２＋The crystal has the structure shown in Figure 1, and it was found to have a structure in which the element Ba is contained within a framework of interconnected tetrahedra composed of bonds between Li, Al or Si and O. In this crystal, the M element, which acts as an activating ion such as Eu, is incorporated into the crystal by substituting some of the Ba element.

[0027] Synthesized and structurally analyzed Ba ２ Li １ Al １ Si ２ O ８ As a crystal that has the same crystal structure as the crystal, Ba ２ Li １ Al １ Si ２ O ８ In some crystals, the lattice constant and atomic positions change due to the substitution of constituent elements with other elements. Here, an example of a constituent element being replaced by another element is Ba ２ Li １ Al １ Si ２ O ８ Some crystals have some or all of the Ba substituted with an element other than Ba, namely element A (where A is at least one element selected from the group consisting of Mg, Ca, Sr, and Ba) or element M (where M is at least one element selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, and Yb).

[0028] Furthermore, some crystals have some or all of the Si substituted with elements D other than Si (where D is one or more elements selected from Si, Ge, Sn, Ti, Zr, and Hf). Furthermore, some crystals have some of the O substituted with nitrogen (N) and / or fluorine (F). That is, element X may further contain at least one element selected from the group consisting of N and F.

[0029] Furthermore, some crystals have some or all of the Al substituted with an element other than Al (where E is one or more elements selected from B, Al, Ga, In, and Sc).

[0030] These substitutions are made so that the overall charge in the crystal becomes neutral. If the elemental substitution does not change the crystal structure, then Ba... ２ Li １ Al １ Si ２ O ８ It is a crystalline system. Since elemental substitution alters the phosphor's luminescence properties, chemical stability, and thermal stability, it is best to select the appropriate element within the range where the crystalline structure is maintained, depending on the application.

[0031] The present invention Ba ２ Li １ Al １ Si ２ O ８ The system crystal can be identified by X-ray diffraction or neutron diffraction. Ba ２ Li １ Al １ Si ２ O ８ In a crystalline system, the lattice constant changes as the constituent elements are replaced by other elements or as activating elements such as Eu are dissolved in solid solution. However, the atomic positions given by the crystal structure, the sites occupied by atoms, and their coordinates do not change so drastically that the chemical bonds between skeletal atoms are broken. In this invention, the results of X-ray diffraction and neutron diffraction are used to determine Pna2 １ The lengths of the Al-O and Si-O chemical bonds (nearest interatomic distances) calculated from the lattice constants and atomic coordinates obtained by Rietveld analysis in the space group are shown in Table 1. ２ Li １ Al １ Si ２ O ８ If the length of the chemical bond calculated from the lattice constant and atomic coordinates of the crystal is within ±5%, it is defined as the same crystal structure. ２ Li １ Al １ Si ２ O ８ We will determine whether it is a systemic crystal. According to experiments, the criterion for this determination is Ba ２ Li １ Al １ Si ２ O ８This is because it has been confirmed that when the length of a chemical bond in a crystal system changes by more than ±5%, the chemical bond breaks and a different crystal is formed.

[0032] Furthermore, if the solid solubility is small, Ba ２ Li １ Al １ Si ２ O ８ A simple method for determining the same crystal structure is as follows: When the lattice constant calculated from the X-ray diffraction results of a new material matches the diffraction peak position (2θ) calculated using the crystal structure data in Table 1 for the main peak, the material can be identified as having the same crystal structure.

[0033] Figure 2 shows Ba ２ Li １ Al １ Si ２ O ８ CuKα calculated from the crystal structure of the crystal １ This figure shows powder X-ray diffraction using a line.

[0034] By comparing Figure 2 with the substance to be compared, Ba ２ Li １ Al １ Si ２ O ８ A simple determination can be made as to whether it is a crystalline system. Ba ２ Li １ Al １ Si ２ O ８ The main peaks of the crystal system can be determined by identifying about 10 peaks with strong diffraction intensity. Table 1 shows Ba in that sense. ２ Li １ Al １ Si ２ O ８ It is important as a reference point for identifying the system crystal. Also, Ba ２ Li １ Al １ Si ２ O ８Even if the crystal structure of a system crystal is not defined using other crystal systems of the orthorhombic crystal, an approximate structure can be defined. In this case, the representation will use different space groups, lattice constants, and plane indices, but the X-ray diffraction results (e.g., Figure 2) and crystal structure (e.g., Figure 1) will remain the same, and the identification methods and results using them will also be identical. For this reason, in this invention, X-ray diffraction analysis will be performed using the orthorhombic crystal system. The method for identifying materials based on Table 1 will be described in detail in the examples below, and only a general explanation will be given here.

[0035] Ba ２ Li １ Al １ Si ２ O ８ A phosphor is obtained by activating a crystal system with at least one element selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb as the M element. Ba ２ Li １ Al １ Si ２ O ８ Since the emission properties such as excitation wavelength, emission wavelength, and emission intensity change depending on the composition of the crystal system, the type and amount of activating elements, it is best to select them according to the application.

[0036] Ba ２ Li １ Al １ Si ２ O ８ An inorganic crystal having the same crystal structure as the crystal shown is Ba ２ Li １ Al １ Si ２ O ８ Mg ２ Li １ Al １ Si ２ O ８ Ca ２ Li １ Al １ Si ２ O ８ , Sr ２ Li １ Al １ Si ２ O ８ (Ba, Mg) ２ Li１ Al １ Si ２ O ８ (Ba, Sr) ２ Li １ Al １ Si ２ O ８ (Ba, Ca) ２ Li １ Al １ Si ２ O ８ Ba ２ Li １ Al １ Si ２ (O, N) ８ Ba ２ Li １ Al １ Si ２ (O, F) ８ , or Ba ２ Li １ (Al, Si) ３ O ８ The phosphors represented by have a stable crystal structure and high luminescence intensity. In this specification, descriptions such as (Ba, Mg), (Ba, Sr), (Al, Si), etc., indicate that each element is present in any ratio. The same applies to others.

[0037] Ba ２ Li １ Al １ Si ２ O ８ An inorganic crystal having the same crystal structure as the crystal shown is Ba ２＋α Li １＋β (Al, Si) ３＋γ O ８ Mg ２＋α Li １＋β (Al, Si) ３＋γ O ８ Ca ２＋α Li １＋β (Al, Si) ３＋γ２＋δ O ８ , Sr ２＋α Li １＋β (Al, Si) ３＋γ O ８ (Ba, Mg) ２＋α Li １＋β (Al, Si) ３＋γ O ８ (Ba, Sr)２＋α Li １＋β (Al, Si) ３＋γ O ８ (Ba, Ca) ２＋α Li １＋β (Al, Si) ３＋γ O ８ Ba ２＋α Li １＋β (Al, Si) ３＋γ (O, N) ８ , or Ba ２＋α Li １＋β (Al, Si) ３＋γ (O, F) ８ Phosphors represented by the composition formula (where -0.3 ≤ α ≤ 0.3, -0.15 ≤ β ≤ 0.15, -0.5 ≤ γ ≤ 0.3) have high luminescence intensity and their color tone can be controlled by changing their composition.

[0038] Ba ２ Li １ Al １ Si ２ O ８ Examples of solid solution crystals of the crystal shown include the above-mentioned Ba ２ Li １ Al １ Si ２ O ８ There are solid-phase crystals in which two or more different inorganic crystals having the same crystal structure as the crystal shown are uniformly mixed.

[0039] The activating element M is preferably Eu. This results in a phosphor that emits blue to green light and exhibits excellent emission intensity when irradiated with vacuum ultraviolet light, ultraviolet light, visible light, electron beams, or X-rays with wavelengths of 100 nm to less than 450 nm. In particular, by controlling the composition, it is possible to emit light with the maximum emission peak in the wavelength range of 480 nm to 500 nm.

[0040] The activating element M may be, for example, Ce. This yields a phosphor that emits purple light. The activating element M may be, for example, Tb. This yields a phosphor that emits green light. The activating element M may be, for example, Mn. This yields a phosphor that emits blue light.

[0041] Ba２ Li １ Al １ Si ２ O ８ In inorganic crystals having the same crystal structure as the crystal shown, those in the orthorhombic system are particularly stable, and phosphors using these as host crystals exhibit high luminescence intensity.

[0042] Furthermore, Ba ２ Li １ Al １ Si ２ O ８ An inorganic crystal having the same crystal structure as the crystal shown is an orthorhombic crystal, and its space group is Pna2 １ Crystals with the following symmetry and lattice constants a, b, and c within the range of a = 0.80608 ± 0.05 nm, b = 1.90798 ± 0.05 nm, and c = 0.50279 ± 0.05 nm are particularly stable, and phosphors using these as host crystals exhibit high emission intensity. Outside this range, the crystal becomes unstable, and the emission intensity may decrease.

[0043] The inorganic compound mentioned above has the composition formula M ｄ A ｅ Li ｆ D ｇ E ｈ X ｉ (wherein the formula d + e + f + g + h + i = 1, M is an element selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, and Yb, A is an element selected from the group consisting of Mg, Ca, Sr, and Ba, D is an element selected from the group consisting of Si, Ge, Sn, Ti, and Zr, E is an element selected from the group consisting of B, Al, Ga, In, and Sc, and X is an element containing at least O), and the parameters d, e, f, g, h, and i are given by: 0.00001 ≤ d ≤ 0.05 0.08 ≤ e ≤ 0.2 0.03 ≤ f ≤ 0.1 0.08 ≤ g ≤ 0.2 0.01 ≤ h ≤ 0.15 0.45 ≤ i ≤ 0.65 Phosphors that satisfy all of these conditions have particularly high luminescence intensity.

[0044] Parameter d represents the amount of activating element added; if it is less than 0.00001, the amount of luminescent ions will be insufficient and the brightness will decrease. If it is more than 0.05, the luminescence intensity may decrease due to concentration quenching caused by interactions between luminescent ions. Parameter e represents the composition of element A, such as Ba; if it is less than 0.08 or more than 0.2, the crystal structure will become unstable and the luminescence intensity will decrease. Parameter f represents the composition of Li; if it is less than 0.03 or more than 0.1, the crystal structure will become unstable and the luminescence intensity will decrease. Parameter g represents the composition of element D, such as Si; if it is less than 0.08 or more than 0.2, the crystal structure will become unstable and the luminescence intensity will decrease. Parameter h represents the composition of element E, such as Al; if it is less than 0.01 or more than 0.15, the crystal structure will become unstable and the luminescence intensity will decrease. Parameter i represents the composition of element X, such as O, N, and F; if it is less than 0.45 or more than 0.65, the crystal structure will become unstable and the luminescence intensity will decrease. Element X is an anion, and the O, N, F ratio is determined so that a neutral charge is maintained with the cations of elements A, M, D, and E.

[0045] The parameters d, e, f, g, h, and i preferably satisfy the following conditions: 0.0001 ≤ d ≤ 0.02, 0.1 ≤ e ≤ 0.18, 0.05 ≤ f ≤ 0.09, 0.1 ≤ g ≤ 0.2, 0.02 ≤ h ≤ 0.12, and 0.5 ≤ i ≤ 0.62. Crystals satisfying such a composition have a stable crystal structure and, in particular, high luminescence intensity.

[0046] The parameters d, e, f, g, h, and i more preferably satisfy the following conditions: 0.0005 ≤ d ≤ 0.015, 0.12 ≤ e ≤ 0.17, 0.05 ≤ f ≤ 0.08, 0.1 ≤ g ≤ 0.18, 0.02 ≤ h ≤ 0.12, and 0.5 ≤ i ≤ 0.6. Crystals satisfying such a composition have a stable crystal structure and, in particular, high luminescence intensity.

[0047] In the above compositional formula, a phosphor containing at least Eu as the activating element M is a phosphor with high luminescence intensity among those of the present invention, and a blue phosphor can be obtained at certain compositions.

[0048] In the above compositional formula, a composition containing at least Ba as element A, at least Si as element D, at least Al as element E, and at least O as element X has a stable crystal structure and high luminescence intensity.

[0049] Furthermore, boron may be included as element E, in which case the boron content is 0.001% by mass or more and 1% by mass or less. This can increase the luminescence intensity.

[0050] The empirical formula is given by Ba using parameters p, q, r, and s. ２－ｐ Eu ｐ Li １＋ｑ Al １＋ｒ Si ２－ｒ O ８－ｓ X' ｓ However, X' is N and / or F, and the phosphors represented by 0 < p ≤ 0.2, -0.15 ≤ q ≤ 0.15, -1 ≤ r ≤ 1, and 0 ≤ s ≤ 1 can have their Eu / Ba ratio, Si / Al ratio, and O / X' ratio changed within a compositional range by changing the parameters p and t while maintaining a stable crystal structure. This allows for continuous changes in excitation and emission wavelengths, making them phosphors that are easy to design materials for.

[0051] Phosphors containing inorganic compounds that are single crystal particles or aggregates of single crystal particles with an average particle size of 0.1 μm to 20 μm have high luminous efficiency and good operability when mounted on LEDs, so it is preferable to control the particle size within this range.

[0052] The impurity elements Fe, Co, and Ni contained in inorganic compounds may reduce the luminescence intensity. By keeping the total amount of these elements in the phosphor below 500 ppm, the effect of reduced luminescence intensity can be minimized.

[0053] As one embodiment of the present invention, the phosphor of the present invention is Ba ２ Li １ Al １ Si ２ O ８There is a phosphor that has a crystalline matrix as its base, in which an activated ion M is solid-dissolved in an inorganic compound, and further contains other crystalline or amorphous phases different from this, with the inorganic compound content being 20% ​​by mass or more. ２ Li １ Al １ Si ２ O ８ This embodiment is useful when the desired properties cannot be obtained with a phosphor in a crystalline system alone, or when adding functions such as conductivity. Ba ２ Li １ Al １ Si ２ O ８ The content of the systemic crystals can be adjusted according to the desired properties, but if it is less than 20% by mass, the luminescence intensity may be low. From this viewpoint, it is preferable that in the phosphor of the present invention, 20% by mass or more is the main component of the inorganic compound described above.

[0054] If conductivity is required for applications such as electron beam excitation, it is advisable to add an inorganic substance that is conductive as another crystalline or amorphous phase.

[0055] Examples of conductive inorganic materials include oxides, oxynitrides, or nitrides containing one or more elements selected from Zn, Al, Ga, In, and Sn, or mixtures thereof. Examples include zinc oxide, aluminum nitride, indium nitride, and tin oxide.

[0056] Ba ２ Li １ Al １ Si ２ O ８ If the desired emission spectrum cannot be obtained with the phosphor alone in the crystalline system, it is advisable to add a second phosphor. Other phosphors include BAM phosphor, β-sialon phosphor, α-sialon phosphor, and (Sr,Ba) ２ Si ５ N ８ Phosphor, CaAlSiN ３ Phosphor, (Ca,Sr)AlSiN ３ Examples include phosphors and the like.

[0057] One embodiment of the present invention is a phosphor that has a peak at a wavelength in the range of 450 nm to 540 nm when irradiated with an excitation source. For example, Ba ２ Li １ Al １ Si ２ O ８ There is a phosphor in which Eu is solid-dissolved in an inorganic crystal having the same crystal structure as the crystal shown. By adjusting the composition, when irradiated with light between 280 nm and 400 nm, it emits fluorescence with an emission peak wavelength in the range of 480 nm to 500 nm, making it suitable for use in white LEDs using blue light and in indicator lights for autonomous driving.

[0058] One embodiment of the present invention is a phosphor that emits light when excited by vacuum ultraviolet light, ultraviolet light, visible light, electron beams, or X-rays having a wavelength of 100 nm or more and less than 450 nm. By using these excitation sources, light emission can be achieved efficiently.

[0059] One embodiment of the present invention is a phosphor whose color, when irradiated with an excitation source, satisfies the range of 0 ≤ x ≤ 0.25 and 0.3 ≤ y ≤ 0.5 in terms of (x, y) values ​​on the CIE 1931 chromaticity coordinate system. The color of the above chromaticity coordinate system is called cyan or turquoise blue, has high visibility, and can be used as an indicator light for automated driving.

[0060] As a phosphor that satisfies such chromaticity coordinates, an inorganic compound is Ba ２－ｐ Eu ｐ Li １＋ｑ Al １＋ｒ Si ２－ｒ O ８－ｓ X' ｓ There is a phosphor represented by (X' is N and / F), where the parameters p, q, r, and s satisfy the following, respectively: 0 < p ≤ 0.2, -0.15 ≤ q ≤ 0.15, -1 ≤ r ≤ 1, and 0 ≤ s ≤ 1.

[0061] The parameters p, q, r, and s preferably satisfy 0.01 ≤ p ≤ 0.16, -0.1 ≤ q ≤ 0.1, -0.5 ≤ r ≤ 0.5, and 0 ≤ s ≤ 0.5. This can result in a phosphor with high luminescence intensity.

[0062] Thus, the phosphor of the present invention is characterized by having a wide excitation range from electron beams and X-rays to ultraviolet and visible light, emitting blue to green light in the 450 nm to 540 nm range, and in particular, the emission wavelength and emission peak width can be adjusted in specific compositions. Due to these emission characteristics, the phosphor of the present invention is suitable for lighting fixtures, image display devices, pigments, and ultraviolet absorbers. The phosphor of the present invention also has the advantage of excellent heat resistance as it does not degrade even when exposed to high temperatures, and excellent long-term stability in oxidizing and humid environments, thus providing durable products.

[0063] The method for producing the phosphor of the present invention is not particularly limited, but for example, a mixture of metal compounds, which can be produced by calcination, ２ Li １ Al １ Si ２ O ８ This can be obtained by calcining a raw material mixture, in which activated ions M are solid-dissolved, using a systemic crystal as the matrix crystal, at a temperature range of 1000°C to 1200°C.

[0064] The main crystal of this invention is orthorhombic with space group Pna2 １ Although it belongs to this category, depending on the synthesis conditions such as firing temperature, crystals with different crystal systems or space groups may be mixed in. However, even in this case, the change in luminescence properties is slight, so it can be used as a high-brightness phosphor.

[0065] This will be explained in detail. The mixture of metal compounds contains element M, element Li, element A, element D, element E, and optionally element X (wherein M is at least one element selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, and Yb; A is at least one element selected from the group consisting of Mg, Ca, Sr, and Ba; D is at least one element selected from the group consisting of Si, Ge, Sn, Ti, and Zr; E is at least one element selected from the group consisting of B, Al, Ga, In, and Sc; and X is an element containing at least O).

[0066] The mixture of metal compounds preferably includes a compound containing M, a compound containing Li, a compound containing A, a compound containing D, a compound containing E, and optionally a compound containing X.

[0067] The starting materials are as follows: The compound containing M is either a single element or a mixture of two or more elements selected from metals, silicides, oxides, carbonates, nitrides, oxynitrides, chlorides, fluorides, and oxyfluorides that contain M.

[0068] The Li-containing compound is either a single element or a mixture of two or more elements selected from Li metal, Li silide, oxide, carbonate, nitride, oxynitride, chloride, fluoride, and oxyfluoride.

[0069] A compound containing A is either a single element or a mixture of two or more elements selected from metals, silicides, oxides, carbonates, nitrides, oxynitrides, chlorides, fluorides, and oxyfluorides that contain A.

[0070] The compound containing D is either a single element or a mixture of two or more elements selected from metals, silicides, oxides, carbonates, nitrides, oxynitrides, chlorides, fluorides, and oxyfluorides that contain D.

[0071] The compound containing E is either an element or a mixture of two or more elements selected from metals, silicides, oxides, carbonates, nitrides, oxynitrides, chlorides, fluorides, and oxyfluorides that contain E.

[0072] The compound containing X is either an element or a mixture of two or more elements selected from oxides, oxynitrides, and oxyfluorides.

[0073] These are preferred because the raw materials are readily available and they have excellent stability. Furthermore, when a compound containing oxygen is used as a compound containing M, Li, A, D, or E, it may be considered a compound containing X.

[0074] Ba activated with EU ２ Li １ Al １ Si ２ O ８When manufacturing crystalline phosphors, it is preferable to use starting materials containing at least europium nitride or oxide, lithium nitride, oxide or carbonate, barium nitride, oxide or carbonate, silicon oxide or silicon nitride, and aluminum oxide or aluminum nitride, as these materials allow the reaction to proceed easily during calcination.

[0075] If the mixture of metal compounds contains oxygen, the calcination may preferably be performed in a reducing atmosphere at the above temperature range for 1 to 12 hours. The reducing atmosphere is a nitrogen-containing atmosphere (for example, N ２ : H ２ The ratio is 95%:5%. If the mixture of metal compounds does not contain oxygen, it is advisable to pre-fire it in air at a temperature range of 900°C to 1100°C prior to firing. There are no particular restrictions on the firing time for pre-fire, but it may be, for example, 1 hour to 12 hours.

[0076] Since the firing atmosphere is an inert atmosphere containing nitrogen, electric furnaces or annular furnaces using the metal resistance heating method or graphite resistance heating method are preferred for firing.

[0077] To manufacture phosphors in powder or aggregate form, it is preferable to fill a container with the raw materials while maintaining a packing density of 40% or less, and then calcine the container. By maintaining a packing density of 40% or less, strong adhesion between particles can be avoided. Here, relative bulk density is the ratio of the mass of the powder filled in the container divided by the volume of the container (bulk density) to the true density of the powder material. Unless otherwise specified, in this invention, relative bulk density is simply referred to as bulk density.

[0078] To produce phosphors in powder or aggregate form, it is preferable that the metal compound mixture be in powder or aggregate form, with an average particle size of 500 μm or less, as this provides excellent reactivity and handling properties.

[0079] As a method for reducing the particle or aggregate size to 500 μm or less, using a spray dryer, sieving, or air classification is preferable because it offers excellent work efficiency and ease of operation.

[0080] To manufacture phosphors in powder or aggregate form, a firing method that does not involve hot pressing, such as atmospheric pressure sintering or gas pressure sintering, without applying external mechanical pressure, is preferred.

[0081] For phosphor powders, an average particle size of 50 nm to 200 μm in volume-based median diameter (d50) is preferable because it results in high emission intensity. The volume-based average particle size can be measured, for example, by microtrac or laser scattering. The particle size of the phosphor powder synthesized by calcination should be adjusted to 50 nm to 200 μm by using one or more methods selected from pulverization, classification, and acid treatment.

[0082] Heat treatment of fluorescent powder after firing, after grinding, or after particle size adjustment at a temperature of 1000°C or higher but below the firing temperature may restore defects and damage caused by grinding. Defects and damage can cause a decrease in luminescence intensity, and heat treatment can restore this intensity.

[0083] During calcination for phosphor synthesis, an inorganic compound that generates a liquid phase at a temperature below the calcination temperature may be added before calcination. Such an inorganic compound that generates a liquid phase acts as a flux, promoting the reaction and grain growth, which can lead to the acquisition of stable crystals and, consequently, improved luminescence intensity.

[0084] Inorganic compounds that produce a liquid phase at temperatures below the calcination temperature include fluorides, chlorides, iodides, bromides, or mixtures of one or more phosphates of one or more elements selected from Li, Na, K, Mg, Ca, Sr, and Ba. Since these inorganic compounds each have different melting points, it is best to use them according to the synthesis temperature.

[0085] Furthermore, washing with a solvent after firing reduces the amount of inorganic compounds that form a liquid phase at temperatures below the firing temperature. This can sometimes increase the luminescence intensity of the phosphor.

[0086] When using the phosphor of the present invention in applications such as light-emitting devices, it is preferable to use it in a form dispersed in a liquid medium. Alternatively, it can be used as a phosphor mixture containing the phosphor of the present invention. A mixture of the phosphor of the present invention dispersed in a liquid medium shall be referred to as a phosphor-containing composition.

[0087] As for the liquid medium that can be used in the phosphor-containing composition of the present invention, any medium can be selected according to the purpose, as long as it exhibits liquid properties under desired usage conditions, appropriately disperses the phosphor of the present invention, and does not cause undesirable reactions. Examples of liquid mediums include uncured addition-type silicone resins, condensation-type silicone resins, modified silicone resins, epoxy resins, polyvinyl resins, polyethylene resins, polypropylene resins, polyester resins, etc. These liquid mediums may be used individually, or two or more may be used in any combination and ratio.

[0088] The amount of liquid medium used can be adjusted as appropriate depending on the application, but generally, the weight ratio of the liquid medium to the phosphor of the present invention is usually 3% by weight or more, preferably 5% by weight or more, and usually 30% by weight or less, preferably 15% by weight or less.

[0089] Furthermore, the phosphor-containing composition of the present invention may contain other optional components in addition to the phosphor and liquid medium of the present invention, depending on its application. Examples of other components include diffusing agents, thickeners, bulking agents, and interfering agents. Specifically, examples include silica-based fine powders such as Aerosil and alumina.

[0090] The light-emitting device of the present invention comprises at least a light-emitting light source and a phosphor, the phosphor including at least the phosphor of the present invention as described above.

[0091] Examples of light-emitting sources include LED light-emitting fixtures, laser diode (LD) light-emitting fixtures, semiconductor lasers, organic electroluminescent (OLED) light-emitting fixtures, and fluorescent lamps. LED light-emitting devices can be manufactured using the phosphor of the present invention by known methods such as those described in Japanese Patent Publication No. 5-152609, Japanese Patent Publication No. 7-99345, and Japanese Patent Publication No. 2927279. In this case, the light-emitting source is preferably one that emits light with a wavelength of 300 to 450 nm, and among these, an ultraviolet (or violet) LED light-emitting element with a wavelength of 330 to 420 nm is preferred. These LED light-emitting elements may be made of nitride semiconductors such as GaN and InGaN, and by adjusting the composition, they can become light-emitting sources that emit light with a predetermined wavelength.

[0092] Examples of light-emitting devices of the present invention include blue to green light-emitting diodes, white light-emitting diodes, lighting fixtures containing multiple white light-emitting diodes, indicator lights for autonomous vehicles, or backlights for liquid crystal panels, all of which contain the phosphor of the present invention.

[0093] In such a light-emitting device, in addition to the phosphor of the present invention, Eu-activated β-sialon green phosphor, Eu-activated α-sialon yellow phosphor, and Eu-activated Sr ２ Si ５ N ８ Orange phosphor, Eu-activated (Ca,Sr)AlSiN ３ Orange phosphor and Eu-activated CaAlSiN ３ The mixture may further contain one or more phosphors selected from red phosphors. Examples of yellow phosphors other than those mentioned above include YAG:Ce, (Ca,Sr,Ba)Si ２ O ２ N ２ You may also use EU, etc.

[0094] One embodiment of the present invention is a light-emitting device in which the light source emits ultraviolet or visible light with a peak wavelength of 300 nm or more and less than 450 nm, and the phosphor of the present invention emits blue to green light. Since the phosphor of the present invention emits cyan or turquoise blue light depending on the control of its composition, such a light-emitting device can be used as an indicator light for automatic driving.

[0095] As one embodiment of the light-emitting device of the present invention, in addition to the phosphor of the present invention, a blue phosphor that emits light with a peak wavelength of 420 nm to 500 nm from a light-emitting light source may be further included. Examples of such blue phosphors include AlN:(Eu,Si),BaMgAl １０ O １７ : Eu, SrSi ９ Al １９ ON ３１ :Eu, LaSi ９ Al １９ N ３２ Examples include Eu, α-Sialon:Ce, and JEM:Ce. This allows for adjustment of the chromaticity of the emitted color.

[0096] As one embodiment of the light-emitting device of the present invention, in addition to the phosphor of the present invention, a green phosphor that emits light with a peak wavelength of 500 nm to 550 nm can be further included by a light-emitting light source. Examples of such green phosphors include β-sialon:Eu,(Ba,Sr,Ca,Mg) ２ SiO ４ :Eu, (Ca, Sr, Ba)Si ２ O ２ N ２ Examples include the EU.

[0097] As one embodiment of the light-emitting device of the present invention, in addition to the phosphor of the present invention, a yellow phosphor that emits light with a peak wavelength of 550 nm to 600 nm from a light-emitting light source may be further included. Examples of such yellow phosphors include YAG:Ce, α-sialon:Eu, and CaAlSiN. ３ : Ce, La ３ Si ６ N １１ Examples include Ce.

[0098] As one embodiment of the light-emitting device of the present invention, in addition to the phosphor of the present invention, a red phosphor that emits light with a peak wavelength of 600 nm to 700 nm from a light-emitting light source may be included. ３ :Eu, (Ca,Sr)AlSiN ３ : Eu, Ca ２ Si ５ N ８ : Eu, Sr ２ Si５ N ８ Examples include the EU.

[0099] Naturally, in addition to the phosphor of the present invention, the above-mentioned blue phosphor, green phosphor, yellow phosphor, and red phosphor can be arbitrarily combined to provide a light-emitting device that emits the desired light.

[0100] As one embodiment of the present invention, using an LED that emits light with a wavelength of 320 nm or more and less than 450 nm as the light source results in high luminous efficiency, thus enabling the construction of a highly efficient light-emitting device.

[0101] The image display device of the present invention comprises at least an excitation source and a phosphor, the phosphor comprising at least the phosphor of the present invention as described above.

[0102] Examples of image display devices include fluorescent display tubes (VFDs), field emission displays (FEDs), plasma display panels (PDPs), cathode ray tubes (CRTs), and liquid crystal displays (LCDs). The phosphor of the present invention has been confirmed to emit light when excited by vacuum ultraviolet light in the range of 100 to 190 nm, ultraviolet light in the range of 190 to 380 nm, electron beams, etc. By combining these excitation sources with the phosphor of the present invention, the above-mentioned image display devices can be constructed.

[0103] The phosphor of the present invention, which is mainly composed of an inorganic compound having a specific chemical composition, has a white object color and can therefore be used as a pigment or fluorescent pigment. That is, when the phosphor of the present invention is irradiated with light such as sunlight or fluorescent lamps, a white object color is observed. Because it exhibits good color development and does not deteriorate over a long period of time, the phosphor of the present invention is suitable as an inorganic pigment. For this reason, when used in paints, inks, paints, glazes, and colorants added to plastic products, it is possible to maintain good color development for a long period of time.

[0104] The phosphor of the present invention is suitable as an ultraviolet absorber because it absorbs ultraviolet light. Therefore, when used as a paint, applied to the surface of plastic products, or kneaded into the interior, it provides a high ultraviolet blocking effect and effectively protects products from ultraviolet degradation.

[0105] The present invention will be further described in detail by the following embodiments, but these are disclosed solely to facilitate understanding of the present invention, and the present invention is not limited to these embodiments.

[0106] [Raw materials used in synthesis] The raw material powders used in the synthesis are as follows: ・Europium oxide (Eu ２ O ３ (Manufactured by Shin-Etsu Chemical Co., Ltd.) ・Cerium oxide (CeO ２ (Manufactured by Shin-Etsu Chemical Co., Ltd.) Terbium oxide (Tb ４ O ７ (Manufactured by Shin-Etsu Chemical Co., Ltd.) ・Manganese carbonate (MnCO3) ３ (Manufactured by High Purity Chemical Laboratory Co., Ltd.) ・Barium carbonate (BaCO3) ３ (Manufactured by Sigma-Aldrich) Strontium carbonate (SrCO3) ３ (Manufactured by Sigma-Aldrich) Calcium carbonate (CaCO3) ３ (Manufactured by Kojun Chemical Laboratory Co., Ltd.) ・Lithium carbonate (Li ２ CO ３ (Manufactured by Kojun Chemical Laboratory Co., Ltd.) ・Aluminum oxide (Al ２ O ３ Daimei Chemical Industry Co., Ltd., Tymicron, specific surface area 13.2 m² ２ / g) ・Aluminum fluoride (AlF, manufactured by Kojun Chemical Laboratory Co., Ltd.) ・Silicon dioxide (SiO ２ (Manufactured by Kojun Chemical Laboratory Co., Ltd.) ・Silicon nitride (Si ３ N ４ Manufactured by UBE Corporation, SN-E10 grade, specific surface area 11.2 m² ２ / g, oxygen content 1.29% by weight, α-type content 95%)

[0107] [Examples 1 to 31] In Examples 1 to 31, inorganic compounds were synthesized according to Tables 2 to 5.

[0108] Specifically, in Example 1, a mixed composition of europium oxide, barium carbonate, lithium carbonate, aluminum oxide, and silicon dioxide was designed in a molar ratio of 0.01:1.98:0.5:0.5:2. Europium oxide, barium carbonate, lithium carbonate, aluminum oxide, and silicon dioxide were weighed out in amounts of 0.113 g, 12.595 g, 0.596 g, 0.822 g, and 3.874 g, respectively, and mixed for 5 minutes using a silicon nitride sintered mortar and pestle. The resulting mixed powder was then placed into an alumina boat. The bulk density of the mixed powder was approximately 30%.

[0109] A boat containing the mixed powder was placed in a tubular furnace. For the calcination process, a nitrogen:hydrogen = 95%:5% mixed gas was first introduced as a reducing atmosphere, and the furnace was heated from room temperature to 1000°C at a rate of 300°C per hour, and held at 1000°C for 5 hours. In this way, the compound of Example 1 was obtained.

[0110] In Examples 2 to 31, the raw material powders were weighed according to the mixed compositions shown in Tables 2 to 4, and mixed in the same manner as in Example 1 to prepare the mixed powders. These mixed powders were then calcined under the calcination conditions shown in Table 5, in the same manner as in Example 1. In this way, the compounds of Examples 2 to 31 were obtained.

[0111] The compounds from Examples 1 to 31 were observed with an optical microscope, and crystal particles measuring 80 μm × 50 μm × 3 μm were collected from the compounds. The compound from Example 1 was analyzed for elements other than Li contained in the crystal particles using a scanning electron microscope (SEM; Hitachi High-Technologies Corporation SU1510) equipped with an energy-dispersive elemental analyzer (EDS; Bruker AXS QUANTAX).

[0112] The analysis of Li contained in the crystal particles was performed using an ICP mass spectrometer attached to a laser ablation device. A laser beam with a beam diameter of 30 μm and a wavelength of 213 nm from a New Wave Research Nd:YAG laser was irradiated onto the crystal particles, and the Li element volatilized from the particles was analyzed using an ICP mass spectrometer.

[0113] EDS and ICP results confirmed the presence of the elements Ba, Li, Al, Si, O, and Eu, and the ratio of the number of atoms of Ba, Li, Al, Si, and O was measured to be 2:1:1:2:8.

[0114] Next, the composite material from Example 1 was fixed to the tip of a glass fiber with an organic adhesive. This was then subjected to X-ray diffraction measurements using a single-crystal X-ray diffractometer with a rotating cathode for MoKα rays (SMART APEX II Ultra, manufactured by Bruker AXS) under conditions of X-ray source output of 50 kV and 50 mA. As a result, it was confirmed that the composite material from Example 1 was a single-crystal particle.

[0115] Next, the crystal structure was determined from the X-ray diffraction measurement results using single-crystal structure analysis software (APEX2, manufactured by Bruker AXS). The obtained crystal structure data is shown in Table 1, and a diagram of the crystal structure is shown in Figure 1. Table 1 describes the crystal system, space group, lattice constants, and types and positions of atoms. Using this data, the shape and size of the unit cell and the arrangement of atoms within it can be determined.

[0116] The compound in Example 1 belongs to the orthorhombic crystal system and has the space group Pna2. １ The crystal belonged to the 33rd space group (International Tables for Crystallography), with lattice constants a, b, and c being a = 0.80608 nm, b = 1.90798 nm, and c = 0.50279 nm, and angles α = 90°, β = 90°, and γ = 90°. The atomic positions were as shown in Table 1. The compounds in Examples 2 to 31 also belonged to the orthorhombic system and space group Pna2. １ It was confirmed that the crystal possesses the characteristic feature.

[0117] The compound of Example 1, determined from the Ba:Li:Al:Si:O ratio and crystal structure data of the EDS measurement, is Ba ２ Li １ Al １ Si ２ O ８ The composition was one in which Eu was dissolved in solid solution. Since this measurement uses a single crystal, the analytical result is pure Ba. ２ Li １ Al １ Si２ O ８ It shows the structure.

[0118] When we examined similar compositions, we found that, as shown in Tables 1 to 5, Ba ２ Li １ Al １ Si ２ O ８ It was found that the crystal could have some or all of the Ba replaced with Ca or Sr while maintaining its crystalline structure. Furthermore, some of the O could be replaced with F or N, and this crystal could be Ba ２ Li １ Al １ Si ２ O ８ It was confirmed that this is one of the compositions of a crystal group that has the same crystal structure as [another crystal].

[0119] Crystal structure data confirmed that this crystal is a novel material not previously reported. Powder X-ray diffraction patterns were calculated from the crystal structure data. The results are shown in Figure 2.

[0120] Figure 2 shows the powder X-ray diffraction and Ba of the compound of Example 7. ２ Li １ Al １ Si ２ O ８ :Eu ２＋ CuKα calculated from the crystal structure １ This figure shows powder X-ray diffraction using a line.

[0121] In the future, we will perform powder X-ray diffraction measurements of the composite material, and if the measured powder pattern is the same as in Figure 2, then Ba in Figure 1 ２ Li １ Al １ Si ２ O ８ It can be determined that crystals are being formed. Furthermore, Ba ２ Li １ Al １ Si ２ O ８ For systems where the crystalline structure remains the same but the lattice constants change, the powder X-ray pattern can be calculated from the lattice constant values ​​obtained by powder X-ray diffraction and the crystal structure data in Table 1. By comparing this with the calculated pattern, Ba can be determined. ２ Li１ Al １ Si ２ O ８ It can be determined that a system of crystals has been formed.

[0122]

[0123]

[0124]

[0125]

[0126] Next, the compounds from Examples 2 to 31 were ground using an agate mortar and pestle, and the K of Cu was added. α Powder X-ray diffraction measurements were performed using a line. The main generated phases and their content percentages are shown in Table 6. The X-ray diffraction patterns of all compounds are shown in Figure 2, based on structural analysis of Ba ２ Li １ Al １ Si ２ O ８ :Eu ２＋ The X-ray diffraction pattern of Ba matches well, ２ Li １ Al １ Si ２ O ８ It was confirmed that the main component is a crystal with the same crystalline structure as the crystal.

[0127]

[0128] As shown in Table 6, the compounds of the present invention (Examples 1 to 30) are Ba ２ Li １ Al １ Si ２ O ８It was confirmed that the compound contained at least 20% by mass of a phase having the same crystalline structure as the crystal as the main generated phase. For example, in Example 13, EDS and ICP measurements confirmed that the compound contained Eu, Ba, Sr, Li, Si, Al, and O. Furthermore, the ratio of Ba:Sr:Li:Si:Al:O was confirmed to be 1.4:0.6:1:1:2:8. The difference between the composition of the mixed raw materials and the chemical composition of the compound suggests that trace amounts of impurities are present in the compound as a second phase. In Example 31, EDS and ICP measurements confirmed that the compound contained Ba, Li, Si, Al, and O.

[0129] Based on the above, the compounds of Examples 1 to 30 are Ba ２ Li １ Al １ Si ２ O ８ It was confirmed that the system crystals contained luminescent ions M such as Eu in solid solution, forming an inorganic compound. Furthermore, the compounds of Examples 1 to 30 have the compositional formula M ｄ A ｅ Li ｆ Si ｇ Al ｈ X ｉ (wherein the formula d+e+f+g+h+i=1, M is an element selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, and Yb, A is an element selected from the group consisting of Mg, Ca, Sr, and Ba, and X is an element containing at least O), and it was found that the parameters d, e, f, g, h, and i satisfy the following: 0.0001≦d≦0.02 0.1≦e≦0.18 0.05≦f≦0.09 0.1≦g≦0.2 0.02≦h≦0.12 0.5≦i≦0.62.

[0130] After firing, the resulting composite (fired body) was coarsely ground, then manually ground using a silicon nitride sintered crucible and mortar, and passed through a 30 μm sieve. The particle size distribution was measured, and the average particle size was found to be 3 to 8 μm.

[0131] Figure 3 shows the appearance of the composite product of Example 1.

[0132] Although shown in grayscale in Figure 3, Figure 3(A) confirms that the compound of Example 1 has a white object color and excellent color development. Although not shown, the compounds of Examples 2 to 30 also showed similar object colors. The inorganic compounds of the present invention exhibit a white object color when irradiated with sunlight or lighting such as fluorescent lamps, and it was found that they can be used as pigments or fluorescent pigments.

[0133] According to Figure 3(B), when the compound of Example 1 was irradiated with a lamp emitting light with a wavelength of 365 nm, it was confirmed that it emitted blue (cyan) light. The compounds of Examples 2 to 30 were also confirmed to emit blue to green light. The compound of Example 31 did not emit any light.

[0134] The emission and excitation spectra of the compound in Example 7 were measured using a fluorescence spectrophotometer. The results are shown in Figure 4 and Table 7. The peak wavelengths of the excitation and emission spectra are shown in Table 8.

[0135] Figure 4 shows the excitation and emission spectra of the compound from Example 7.

[0136]

[0137] According to Figure 4, the compound of Example 7 was found to be most efficiently excited at 355 nm, and the emission spectrum when excited at 355 nm showed blue emission with a peak at 499 nm. Furthermore, the emission color of the compound of Example 7 was cyan, with x = 0.204 and y = 0.421 in CIE 1931 chromaticity coordinates (x, y).

[0138] According to Table 7, the synthesis of Example 7 showed the highest internal quantum efficiency when excited at 405 nm, while the external quantum efficiency was similar when excited at 365 nm or 405 nm.

[0139]

[0140] According to Table 8, the compounds of the present invention can be excited by ultraviolet and visible light in the range of 230 nm to 420 nm and have been confirmed to be phosphors that emit blue to green light. In particular, the emission colors of the compounds in Examples 1 to 3, Examples 5 to 12, Examples 21 to 26, Example 28 and Example 30 were confirmed to be within the range of 0 ≤ x ≤ 0.25 and 0.3 ≤ y ≤ 0.5 in the CIE 1931 chromaticity coordinates (x, y).

[0141] The temperature characteristics of the compound in Example 7 were investigated. When the compound in Example 7 was heated to 100°C and excited with 365 nm ultraviolet light, the maximum peak intensity and integrated intensity were calculated to be 0.90 and 0.93, respectively. At this time, the maximum peak intensity and integrated intensity at room temperature were set to 1. From this, it is suggested that the compound of the present invention is a phosphor with excellent heat resistance.

[0142] Based on the above, the synthetic product of the present invention is Ba ２ Li １ Al １ Si ２ O ８ The inorganic compound in which luminescent ions M such as Eu are solid-dissolved in a crystalline system was found to be a phosphor. According to Tables 3 and 8, it can be seen that by controlling the composition to a specific level, a phosphor that emits blue (especially cyan) light can be obtained. Such an inorganic compound is Ba ２－ｐ Eu ｐ Li １＋ｑ Al １＋ｒ Si ２－ｒ O ８－ｓ X' ｓ (where X' is N and / or F, and the parameters p, q, r, and s satisfy 0 < p ≤ 0.2, -0.15 ≤ q ≤ 0.15, -1 ≤ r ≤ 1, and 0 ≤ s ≤ 1, respectively.)

[0143] Next, a light-emitting device (lighting fixture) using the phosphor of the present invention will be described.

[0144] [Example 32] Figure 5 is a schematic diagram showing a lighting fixture (bullet-shaped LED lighting fixture) according to the present invention.

[0145] A so-called bullet-shaped white light-emitting diode lamp (1) shown in Figure 5 was fabricated. It has two lead wires (2, 3), one of which (2) has a recess on which an ultraviolet light-emitting diode element (4) with an emission peak at 365 nm is mounted. The lower electrode of the ultraviolet light-emitting diode element (4) and the bottom surface of the recess are electrically connected by conductive paste, and the upper electrode and the other lead wire (3) are electrically connected by a gold wire (5). A phosphor (7) is dispersed in resin and mounted near the light-emitting diode element (4). This first resin (6) in which the phosphor is dispersed is transparent and covers the entire ultraviolet light-emitting diode element (4). The tip of the lead wire including the recess, the ultraviolet light-emitting diode element, and the first resin in which the phosphor is dispersed are sealed by a transparent second resin (8). The transparent second resin (8) is generally cylindrical in shape, and its tip has a lens-shaped curved surface, hence the name bullet-shaped.

[0146] As the phosphor (7), the compound from Example 7 was mixed with epoxy resin, and an appropriate amount of this was dropped using a dispenser to form a first resin (6) in which the phosphor (7) was dispersed.

[0147] When current is passed through the lead wires (2, 3), the ultraviolet light-emitting diode element (4) emits light at 365 nm. This light excites the composite material of Example 7, causing it to function as a light-emitting device that emits blue light. The resulting light-emitting device produced cyan light, with x = 0.204 and y = 0.421.

[0148] [Example 33] Figure 6 is a schematic diagram showing a lighting fixture (substrate-mounted LED lighting fixture) according to the present invention.

[0149] A chip-type white light-emitting diode lamp (11) for substrate mounting, as shown in Figure 6, was fabricated. Two lead wires (12, 13) are fixed to a white alumina ceramic substrate (19) with high visible light reflectivity. One end of each wire is located approximately in the center of the substrate, while the other end is exposed to the outside and serves as an electrode to be soldered when mounted on an electrical circuit board. One of the lead wires (12) has an ultraviolet light-emitting diode element (14) with a peak emission wavelength of 365 nm mounted and fixed to one end so that it is located in the center of the substrate. The lower electrode of the ultraviolet light-emitting diode element (14) and the lower lead wire are electrically connected by conductive paste, and the upper electrode and the other lead wire (13) are electrically connected by a gold wire (15).

[0150] The first resin (16), and the compound of Example 7, a green phosphor (β-sialon: Eu), and a red phosphor (CaAlSiN ３ A mixture of phosphor (17) and (Eu) is mounted near the ultraviolet light-emitting diode element. The first resin in which this phosphor is dispersed is transparent and covers the entire ultraviolet light-emitting diode element (14).

[0151] Furthermore, a wall member (20) with a hole in the center is fixed to the ceramic substrate. The wall member (20) has a hole in the center for housing a resin (16) in which an ultraviolet light-emitting diode element (14) and a phosphor (17) are dispersed, and the part facing the center is sloped. This slope is a reflective surface for extracting light forward, and the curved shape of the slope is determined considering the direction of light reflection. In addition, at least the surface constituting the reflective surface is a white or metallic surface with high visible light reflectivity. In this embodiment, the wall member (20) is made of white silicone resin.

[0152] The hole in the center of the wall member forms a recess in the final shape of the chip-type light-emitting diode lamp, and a transparent second resin (18) is filled into this recess so as to completely seal the first resin (16) in which the ultraviolet light-emitting diode element (14) and phosphor (17) are dispersed. In this embodiment, the same epoxy resin was used for both the first resin (16) and the second resin (18).

[0153] When current is passed through the lead wires (12, 13), the ultraviolet light-emitting diode element (14) emits 365 nm light. This light excites the composite, green phosphor, and red phosphor of Example 7, causing them to emit blue, green, and red light. The light from these phosphors is then mixed to produce white light, functioning as an illumination device.

[0154] Next, we will describe an example of an image display device design using the phosphor of the present invention.

[0155] [Example 34] Figure 7 is a schematic diagram showing an image display device (plasma display panel) according to the present invention.

[0156] Red phosphor (CaAlSiN ３ :Eu)(31), green phosphor (β-sialon:Eu ２＋ The composite (32) and the compound (33) of Example 7 of the present invention are coated on the inner surfaces of each cell (34, 35, 36) which are arranged on a glass substrate (44) via electrodes (37, 38, 39) and a dielectric layer (41). When current is applied to the electrodes (37, 38, 39, 40), vacuum ultraviolet light is generated in the cell by Xe discharge, which excites the phosphors and emits red, green, and blue visible light. This light is observed from the outside through the protective layer (43), the dielectric layer (42), and the glass substrate (45), and the device functions as an image display device.

[0157] [Example 35] Figure 8 is a schematic diagram showing an image display device (field emission display panel) according to the present invention.

[0158] The composite material (56) of Example 7 of the present invention is coated on the inner surface of the anode (53). By applying a voltage between the cathode (52) and the gate (54), electrons (57) are emitted from the emitter (55). The electrons are accelerated by the voltage between the anode (53) and the cathode and collide with the composite material (56) of Example 7, emitting blue light. The whole is protected by glass (51). The figure shows one light-emitting cell consisting of one emitter and one phosphor, but in reality, in addition to blue, many red and green cells are arranged to form a display that emits a variety of colors. There is no particular specification for the phosphors used in the green and red cells, but it is preferable to use ones that emit high brightness with a low-speed electron beam.

[0159] The phosphor of the present invention has different luminescence characteristics (luminescence color, excitation characteristics, and emission spectrum) from conventional phosphors, and exhibits high luminescence intensity even when combined with LEDs with wavelengths less than 450 nm. It is also chemically and thermally stable, and exhibits minimal brightness reduction when exposed to an excitation source. Therefore, it is a suitable phosphor for use in VFDs, FEDs, PDPs, CRTs, vehicle indicator lights, white LEDs, and the like. It is expected to be widely utilized in material design for various display devices in the future, contributing to industrial development.

[0160] 1. Bullet-shaped light-emitting diode lamp. 2, 3. Lead wires. 4. Light-emitting diode element. 5. Bonding wires. 6, 8. Resin. 7. Phosphor. 11. Chip-type white light-emitting diode lamp for substrate mounting. 12, 13. Lead wires. 14. Light-emitting diode element. 15. Bonding wires. 16, 18. Resin. 17. Phosphor. 19. Alumina ceramic substrate. 20. Side members. 31. Red phosphor. 32. Green phosphor. 33. Blue phosphor. 34, 35, 36. Ultraviolet light-emitting cell. 37, 38, 39, 40. Electrodes. 41, 42. Dielectric layer. 43. Protective layer. 44, 45. Glass substrate. 51. Glass. 52. Cathode. 53. Anode. 54. Gate. 55. Emitter. 56. Phosphor. 57. Electron.

Claims

1. A mixture containing Li, A, D, E, and X (where A is at least one element selected from the group consisting of Mg, Ca, Sr, and Ba; D is at least one element selected from the group consisting of Si, Ge, Sn, Ti, and Zr; E is at least one element selected from the group consisting of B, Al, Ga, In, and Sc; and X is an element containing at least O) ２ Li １ Al １ Si ２ O ８ A phosphor comprising an inorganic crystal having the same crystal structure as the crystal shown, or an inorganic compound in which element M (wherein M is at least one element selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, and Yb) is solid-dissolved in the solid solution crystal.

2. The Ba ２ Li １ Al １ Si ２ O ８ The phosphor according to claim 1, wherein the inorganic crystal having the same crystal structure as the crystal represented by is a cubic crystal.

3. The above Ba ２ Li １ Al １ Si ２ O ８ Inorganic crystals having the same crystal structure as the crystal shown are in the space group Pna2 １ The phosphor according to claim 2, having the following symmetry, and the lattice constants a, b, and c are in the range of a = 0.80608 ± 0.05 nm, b = 1.90798 ± 0.05 nm, and c = 0.50279 ± 0.05 nm.

4. The phosphor according to any one of claims 1 to 3, wherein element A comprises at least Ba, element D comprises at least Si, and element E comprises at least Al.

5. The phosphor according to any one of claims 1 to 4, wherein the element X further comprises at least one element selected from the group consisting of N and F.

6. The phosphor according to any one of claims 1 to 5, wherein the M element comprises at least Eu.

7. The inorganic compound is of compositional formula M ｄ A ｅ Li ｆ D ｇ E ｈ X ｉ (wherein the formula d + e + f + g + h + i = 1, M is an element selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, and Yb, A is an element selected from the group consisting of Mg, Ca, Sr, and Ba, D is an element selected from the group consisting of Si, Ge, Sn, Ti, and Zr, E is an element selected from the group consisting of B, Al, Ga, In, and Sc, and X is an element containing at least O), and the parameters d, e, f, g, h, and i are given by: 0.00001 ≤ d ≤ 0.05 0.08 ≤ e ≤ 0.2 0.03 ≤ f ≤ 0.1 0.08 ≤ g ≤ 0.2 0.01 ≤ h ≤ 0.15 0.45 ≤ i ≤ 0.65 A phosphor according to any one of claims 1 to 6, represented by a composition within the range that satisfies the conditions.

8. The phosphor according to claim 7, wherein the parameters d, e, f, g, h, and i satisfy the following conditions: 0.0001 ≤ d ≤ 0.02, 0.1 ≤ e ≤ 0.18, 0.05 ≤ f ≤ 0.09, 0.1 ≤ g ≤ 0.2, 0.02 ≤ h ≤ 0.12, and 0.5 ≤ i ≤ 0.

62.

9. A phosphor according to any one of claims 1 to 8, which emits fluorescence having a peak in the wavelength range of 450 nm to 540 nm when irradiated with an excitation source.

10. The phosphor according to claim 9, wherein the excitation source is vacuum ultraviolet light, ultraviolet light or visible light, electron beam or X-ray, having a wavelength of 100 nm or more and less than 450 nm.

11. The above Ba ２ Li １ Al １ Si ２ O ８ A phosphor according to any one of claims 1 to 10, wherein Eu is solid-dissolved in an inorganic crystal having the same crystal structure as the crystal shown, and when irradiated with light of 280 nm to 400 nm, it emits fluorescence having an emission peak wavelength in the range of 480 nm to 500 nm.

12. The phosphor according to claim 11, wherein the color emitted when an excitation source is irradiated satisfies the conditions 0 ≤ x ≤ 0.25 and 0.3 ≤ y ≤ 0.5 in the (x, y) values ​​on the CIE 1931 chromaticity coordinate system.

13. The inorganic compound is Ba ２－ｐ Eu ｐ Li １＋ｑ Al １＋ｒ Si ２－ｒ O ８－ｓ X' ｓ A phosphor according to any one of claims 1 to 12, wherein X' is N and / or F, and the parameters p, q, r, and s satisfy 0 < p ≤ 0.2, -0.15 ≤ q ≤ 0.15, -1 ≤ r ≤ 1, and 0 ≤ s ≤ 1, respectively.

14. A method for producing a phosphor according to any one of claims 1 to 13, comprising calcining a mixture of a metal compound containing element M, element Li, element A, element D, element E, and optionally element X (wherein M is at least one element selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, and Yb; A is at least one element selected from the group consisting of Mg, Ca, Sr, and Ba; D is at least one element selected from the group consisting of Si, Ge, Sn, Ti, and Zr; E is at least one element selected from the group consisting of B, Al, Ga, In, and Sc; and X is an element containing at least O) at a temperature range of 1000°C to 1200°C.

15. A light-emitting device comprising at least a light-emitting light source and a phosphor, wherein the phosphor includes the phosphor described in any one of claims 1 to 13.

16. The light-emitting device according to claim 15, wherein the light-emitting light source is a light-emitting diode (LED), laser diode (LD), semiconductor laser, or organic EL light-emitting element (OLED) that emits light with a wavelength of 330 nm or more and 420 nm or less.

17. The light-emitting device according to claim 15 or 16, wherein the light-emitting device is a white light-emitting diode, a lighting fixture including a plurality of the white light-emitting diodes, a vehicle indicator light, or a backlight for a liquid crystal panel.

18. An image display device comprising at least an excitation source and a phosphor, wherein the phosphor comprises the phosphor described in any one of claims 1 to 13.

19. A pigment comprising the phosphor described in any one of claims 1 to 13.

20. An ultraviolet absorber comprising a phosphor according to any one of claims 1 to 13.

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