JP5071714B2 - Phosphor, method for producing the same, and light emitting device using the same - Google Patents

Description

The present invention relates to an AAlSiON ₂ crystal (where A is an element selected from the group consisting of Li, Na and K), or a phosphor having a solid solution crystal as a base crystal, a method for producing the same, and a method for producing the same Regarding usage. More specifically, the application relates to a lighting apparatus and a light-emitting apparatus for an image display device using the property of the phosphor, that is, the characteristic of emitting light having a peak at a wavelength of 400 nm to 700 nm.

  The phosphor is a fluorescent display tube (VFD (Vacuum-Fluorescent Display)), a field emission display (FED (Field Emission Display)) or a SED (Surface-Condition Electron-Emitter Display (P panel)). ), Cathode ray tube (CRT (Cathode-Ray Tube)), white light emitting diode (LED (Light-Emitting Diode)), and the like. In any of these applications, in order to cause the phosphor to emit light, it is necessary to supply the phosphor with energy for exciting the phosphor. When excited by a high energy excitation source, it emits visible light. However, as a result of exposure of the phosphor to the excitation source as described above, there is a demand for a phosphor that is liable to lower the luminance of the phosphor and has no luminance reduction. For this reason, sialon phosphors and oxynitride phosphors are used as phosphors with little reduction in luminance instead of conventional phosphors such as silicate phosphors, phosphate phosphors, aluminate phosphors, and sulfide phosphors. In addition, phosphors based on inorganic crystals containing nitrogen in the crystal structure, such as nitride phosphors, have been proposed.

An example of a sialon phosphor is manufactured by a manufacturing process generally described below. First, silicon nitride (Si ₃ N ₄ ), aluminum nitride (AlN), and europium oxide (Eu ₂ O ₃ ) are mixed at a predetermined molar ratio, and the temperature is 1700 ° C. in nitrogen at 1 atm (0.1 MPa). It is manufactured by holding for 1 hour and firing by a hot press method (see, for example, Patent Document 1). It has been reported that α sialon activated by Eu ²⁺ ions obtained by this process becomes a phosphor that emits yellow light of 550 to 600 nm when excited by blue light of 450 to 500 nm. In addition, a phosphor obtained by adding a rare earth element to β-type sialon (see Patent Document 2) is known. A phosphor activated with Tb, Yb, or Ag becomes a phosphor emitting green light of 525 nm to 545 nm. It is shown. Furthermore, a green phosphor obtained by activating Eu ²⁺ on a β-type sialon (see Patent Document 3) is known.

An example of an oxynitride phosphor, JEM phase _{(LaAl (Si 6-z Al} z) N 10-z O z) blue phosphor were activated with Ce as host crystals (see Patent Document 4), La ₃ A blue phosphor in which Ce is activated using Si ₈ N ₁₁ O ₄ as a base crystal (see Patent Document 5) is known.

As an example of a nitride phosphor, a red phosphor (see Patent Document 6) in which Eu ²⁺ is activated using CaAlSiN ₃ as a base crystal is known. In addition, as a phosphor having AlN as a base material, Non-Patent Document 1 synthesizes an amorphous ceramic thin film by magnetron sputtering of a phosphor added with trivalent Eu ions (ie, AlN: Eu ³⁺ ) at room temperature. It is reported that an orange or red phosphor having an emission peak from Eu ³⁺ ions at 580 nm to 640 nm was obtained. Non-Patent Document 2 reports that a phosphor obtained by activating Tb ³⁺ on an amorphous AlN thin film emits green light having a peak at 543 nm by electron beam excitation. Non-Patent Document 3 reports a phosphor in which Gd ³⁺ is activated on an AlN thin film. However, all of these AlN-based phosphors are amorphous thin films that are not suitable for illumination and image display device applications.

As a blue phosphor for use in an image display device (VFD, FED, SED, CRT) using an electron beam as an excitation source, a phosphor in which Ce is solid-solved with Y ₂ SiO ₅ as a base crystal (Patent Document 7) or ZnS A phosphor (Patent Document 8) in which a light-emitting ion such as Ag is dissolved is reported.

Japanese Patent No. 3668770 JP-A-60-206889 JP 2005-255895 A International Publication No. 2005/019376 Pamphlet JP 2005-112922 A International Publication No. 2005/052087 Pamphlet JP 2003-55657 A JP 2004-285363 A Meghan L. Caldwell, et al., “Visible Luminescent Activation of Amorphous AIN: Eu Thin-Film Phosphorus with Osygen,” MRS Internet Journal Nitride 6th Year, page 13; H. H. Richardson, et al., “Thin-film electroluminescent devices grown on plastic substituting using an amorphous AIN: Tb3 + phosphor”, Vol. 9, pages 207, vol. U. Vetter, et al., “Intense ultraviolet cathodoluminescence at 318 nm from Gd3 + -doped AlN”, Physics Letters, 83, 11, 2145-2147, 2003.

  For use of a white LED using an ultraviolet LED or a blue LED as an excitation source, a phosphor having excellent durability and high luminance is required. Furthermore, in order to improve color reproducibility (color rendering) as illumination, phosphors of various colors such as purple, blue, green, yellow, orange and red are required. Furthermore, the conventional phosphor using oxynitride as a host (matrix crystal) is an insulating material, and its emission intensity is low even when irradiated with an electron beam. There is a need for a phosphor that emits light with high brightness using an electron beam. In addition to conventional sialon phosphors and oxynitride phosphors, phosphors made of various materials can be appropriately selected according to the application, which is preferable in terms of design.

  The oxide phosphor disclosed in Patent Document 7 used for electron beam excitation may deteriorate during use and decrease the emission intensity, and the color balance may change in the image display device. The sulfide phosphor disclosed in Patent Document 8 may be decomposed during use, and sulfur may be scattered to contaminate the device.

  An object of the present invention is to respond to such a demand, and is to provide a phosphor made of a material different from a conventional rare earth activated sialon phosphor and an oxide phosphor. The aim is to provide blue-green, green and yellow phosphor powders. Furthermore, it is intended to provide a phosphor powder that emits light efficiently with an electron beam.

Under the circumstances, the present inventor pays attention to an AAlSiON ₂ crystal (A is an element selected from the group consisting of Li, Na and K), and an AAlSiON ₂ crystal or an AAlSiON ₂ solid solution crystal. And at least a metal ion M (wherein M is an element selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Tm, and Yb). As a result of intensive research on oxynitrides, it has been found that a phosphor having a specific composition range, a specific solid solution state, and a specific crystal phase becomes a phosphor having an emission peak at a wavelength in the range of 400 nm to 700 nm. I found it. Among them, those with a specific composition range in which Ce is dissolved as an M element have high-brightness blue to blue-green light emission by ultraviolet light or electron beam excitation, and are used for illumination or image display excited by an electron beam. I found it suitable for the device. Further, those having a specific composition range in which Eu is dissolved as an M element have a light emission of green to yellow with high luminance by ultraviolet light or electron beam excitation, and are used for illumination applications or image display devices excited by electron beams. I found it suitable.

  According to Patent Documents 1 to 8 and Non-Patent Documents 1 to 3, it is reported that a phosphor is obtained by adding optically active ions such as Eu and Ce ions using nitride or oxynitride ceramics as a base crystal. However, it is known that the excitable wavelength and the emission wavelength differ depending on the type of the host crystal and the optically active ion to be added, and the uses are different.

The AAlSiON ₂ crystal, particularly the LiAlSiON ₂ crystal, was found for the first time by the present inventor, and the AAlSiON ₂ crystal or solid solution crystal in which optically active ions were dissolved was excited by ultraviolet rays, visible light, electron beams, or X-rays. The important discovery that the phosphor can be used as a phosphor having high luminance emission has been found for the first time by the present inventors.

  As a result of further diligent research based on this knowledge, a phosphor exhibiting a high-luminance light emission phenomenon in a specific wavelength region, a method for producing the phosphor, a lighting device having excellent characteristics, and an image display device are provided. Succeeded. The details will be described below.

(Invention 1) AAlSiON ₂ crystal that emits fluorescence by excitation energy from an excitation source (where A is an element selected from the group consisting of Li, Na, and K) or a solid solution crystal of AAlSiON ₂ A phosphor, wherein the AAlSiON ₂ crystal or the solid solution crystal of AAlSiON ₂ includes at least M element (where M is Mn, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm). And at least one element selected from the group consisting of Yb).
(Invention 2) The phosphor according to the invention 1, the crystal structure of the AAlSiON ₂ crystal or AAlSiON ₂ solid solution crystal is characterized by having the same crystal structure as the crystal structure of LiAlSiON ₂ crystals.
(Invention 3) The phosphor according to Invention 1, wherein the element A is Li.
(Invention 4) The phosphor according to Invention 1, wherein the A element contains at least Li, the M element contains at least Ce, and has a peak in a wavelength range of 440 nm to 520 nm by the excitation energy. It emits fluorescence.
(Invention 5) The phosphor according to Invention 1, wherein the element A contains at least Li, the element M contains at least Eu, and has a peak in a wavelength range of 500 nm or more and 570 nm or less due to the excitation energy. It emits fluorescence.
(Invention 6) The phosphor according to Invention 1, wherein the phosphor is represented by a composition formula M _a A _b Al _{c S} i _d O _e N _f (where a + b + c + d + e + f = 1), and parameters a, b, c, d, e, f are
0.00001 ≦ a ≦ 0.1 (i)
0.12 ≦ b ≦ 0.24 (ii)
0.12 ≦ c ≦ 0.24 (iii)
0.12 ≦ d ≦ 0.24 (iv)
0.12 ≦ e ≦ 0.24 (v)
0.24 ≦ f ≦ 0.40 (vi)
It is characterized by satisfying the above conditions.
(Invention 7) M metal, oxide, carbonate, nitride, fluoride, chloride, oxynitride, a compound containing M or a combination thereof, and A metal, oxide, carbonate, nitride, Fluorides, chlorides, oxynitrides, compounds containing A or combinations thereof and Al metals, oxides, carbonates, nitrides, fluorides, chlorides, oxynitrides, compounds containing Al or their A raw material mixture containing at least a combination and a metal, oxide, carbonate, nitride, fluoride, chloride, oxynitride, compound containing Si, or a combination thereof of Si, and having a relative bulk density of 40% or less The phosphor according to the first aspect of the invention is fired in a temperature range of 1200 ° C. or more and 2200 ° C. or less in a nitrogen atmosphere of 0.1 MPa or more and 100 MPa or less after filling the container in a state maintained at a rate. Method.
(Invention 8) A lighting apparatus comprising an excitation source and a phosphor that emits fluorescence by excitation light therefrom, wherein the excitation source emits excitation light having a wavelength of 330 to 420 nm, A part of the luminaire is the phosphor according to any one of Inventions 1 to 6.
(Invention 9) An image display device comprising an excitation source and a phosphor emitting fluorescence by excitation energy therefrom, wherein at least a part of the phosphor is the phosphor according to any one of Inventions 1 to 6. An image display device.
(Invention 10) The image display device according to Invention 9, wherein the image display device is any one of a fluorescent display tube (VFD), a field emission display (FED or SED), or a cathode ray tube (CRT), The excitation source is an electron beam having an acceleration voltage of 10 V to 30 kV.

The phosphor of the present invention contains AAl ₂ Si ₅ O ₂ N ₈ crystal or a solid solution crystal in which a metal ion serving as an emission center is dissolved, as a main component, so that the emission intensity at 400 nm to 700 nm is high. Excellent as blue, blue-green, green and yellow phosphors for white LED applications. Even when the phosphor is exposed to an excitation source, the luminance of the phosphor hardly decreases. Furthermore, it is a useful phosphor that can be suitably used for VFD, FED, SED, CRT and the like because it emits light efficiently with an electron beam.

  Examples of the present invention will be described in detail below.

The phosphor of the present invention is mainly composed of an AAlSiON ₂ crystal (provided that at least one element A is selected from the group consisting of Li, Na and K) or a solid solution crystal of AAlSiON _{2 as} a base crystal. Include as.

AAlSiON ₂ crystal or AAlSiON ₂ solid solution crystal can be identified by X-ray diffraction or neutron diffraction. As for the details of the crystal structure, the crystal structure and the X-ray diffraction pattern are uniquely determined from the lattice constant, space group, and atomic position data described later. In addition to pure AAlSiON ₂ crystals, those in which the lattice constant is changed by replacing the constituent elements with other elements are also included as part of the present invention.

The AAlSiON ₂ crystal or the AAlSiON ₂ solid solution crystal belongs to the LiAlSiON ₂ crystal or its solid solution crystal and has the same crystal structure as that of the LiAlSiON ₂ crystal. Specifically, according to the crystal structure analysis of the LiAlSiON ₂ crystal by the present inventor, the crystal belongs to Cmc2 ₁ (International Tables for Crystallography No. 36 space group), and the atomic coordinate positions shown in Table 2 described later are included. Occupy. In this specification, “having the same crystal structure” means that, as described later, the difference between the chemical bond length calculated from Table 2 and the chemical bond length calculated by measurement is ± 15%. Intended for cases within.

Here, the LiAlSiON ₂ crystal and its solid solution crystal will be described in detail. LiAlSiON ₂ crystals have a skeleton similar to Si ₂ N ₂ O crystals (mineral name sonoite) and CaAlSiN ₃ crystals. That is, Li occupies the Ca position of the CaAlSiN ₃ crystal and O occupies a part of the N position, and has a structure in which atomic coordinates are changed as the elements are different. The LiAlSiON ₂ solid solution crystal refers to a crystal in which the lattice constant is changed by replacing the constituent element of the crystal with another element or entering another crystal element into the crystal lattice.

“The constituent element is replaced by another element” means that in the LiAlSiON ₂ crystal, the position of Si is the element D (where D is a group consisting of tetravalent metal elements, preferably Ge, Sn, Ti, Zr and Hf). At least one element selected from the group consisting of a group consisting of trivalent metal elements, preferably B, Ga, In, Sc, Y, La, Gd, and At least one element selected from the group consisting of Lu, and / or the position of N or the position of O is selected from the group consisting of element X (where X is O, N and F) Intended to be replaced by (element).

In addition, “another element penetrates into the crystal lattice” means that elements such as Sc, Y, La, Lu, B, Ga, C, Ge, P, S, F, and Cl are located in the crystal lattice. I intend to. In this case, the solid solution crystal of LiAlSiON ₂ crystals by solid solution, while maintaining the structure of LiAlSiON ₂ crystals, Al, Si, O, part of the N or all are substituted with other elements, or other elements Penetrates into the crystal. Hereinafter, a LiAlSiON ₂ crystal or a crystal belonging to a solid solution crystal thereof is referred to as a LiAlSiON ₂ group crystal for simplicity.

The LiAlSiON _{2 group} crystal has a crystal structure in which Li, Si, Al, O, or N as a constituent component thereof is replaced by another element, or the lattice constant is changed by dissolving a metal element such as Sc. The atomic position given by the site occupied by the atoms and their coordinates does not change so much that the chemical bond between the skeletal atoms is broken. In the present invention, X-ray diffraction or neutron-ray diffraction results Cmc2 ₁ space group with Rietveld analysis to determined the lattice constant and the length of the chemical bond calculated Al-N and Si-N from the atomic coordinates ( When the distance between adjacent atoms is within ± 15% compared to the length of the chemical bond calculated from the lattice constant and atomic coordinates of LiAlSiON ₂ shown in Table 2 in the Examples, the same crystal structure is defined as LiAlSiON. Judgment whether or not it is a genus ₂ crystal. This criterion is that when the chemical bond length changes beyond ± 15%, the chemical bond is broken and another crystal is formed.

Furthermore, when the amount of solid solution is small, there is the following method as a simple determination method for LiAlSiON _{2 group} crystals. When the position of the main peak (2θ) calculated using the lattice constant and the plane index calculated from the X-ray diffraction results measured for the new substance matches the experimental value and the calculated value, the crystal structure is identified as the same. can do. As the main peak, it is good to judge with about ten strong diffraction intensities. In that sense, Table 2 serves as a reference in specifying the LiAlSiON _{2 group} crystal and is important. In addition, an approximate structure can be defined by using another crystal system such as a monoclinic system or a hexagonal system for the crystal structure of the LiAlSiON _{2 group} crystal, in which case different space groups, lattice constants, and planes can be defined. The expression is expressed using an index, but the X-ray diffraction result is not changed, and the identification method and identification result using the result are the same. For this reason, in the present invention, X-ray diffraction analysis is performed as an orthorhombic system.

Next, an AAlSiON ₂ crystal (wherein the A element is at least one element selected from the group consisting of Li, Na and K), which is the parent crystal of the present invention, will be described in detail. The AAlSiON ₂ crystal according to the present invention is a LiAlSiON _{2 group} crystal, which can be identified by X-ray diffraction or neutron diffraction, and shows the same diffraction as the X-ray diffraction result of the above LiAlSiON ₂ crystal. Further, the constituent elements of the crystal is replaced with another element, or a crystal lattice constant is changed by other elements penetrating into the crystal lattice is referred to as AAlSiON ₂ solid solution crystal, in addition to AAlSiON ₂ crystals, AAlSiON _{The two} solid solution crystal is also a host crystal constituting the phosphor of the present invention. Such an AAlSiON ₂ solid solution crystal is also a LiAlSiON _{2 group} crystal and is a substance exhibiting the same diffraction as the above-mentioned X-ray diffraction result of the LiAlSiON ₂ crystal.

“The constituent element is replaced by another element” means that in the AAlSiON ₂ crystal, the position of Si described above is replaced by element D, the position of Al is replaced by element E, and / or the position of N or O In addition to replacing the position with the element X, it is intended that in the AAlSiON ₂ crystal, the position of A is replaced with at least one element selected from the group consisting of Li, Na and K. Further, “other elements enter into the crystal lattice” means that elements such as Sc, Y, La, Lu, B, Ga, C, Ge, P, S, F, and Cl are crystallized as described above. It is intended to be located within the grid.

In the present invention, the above-described AAlSiON ₂ crystal or AAlSiON ₂ solid solution crystal is used as a base crystal, and an optically active metal element M (where M is Mn, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy). , At least one element selected from the group consisting of Tm and Yb) is dissolved, whereby a phosphor having excellent optical characteristics is obtained. Among AAlSiON ₂ crystals or solid solution crystals thereof, phosphors having A as Li, that is, LiAlSiON ₂ crystals or solid solution crystals thereof as a host are high-luminance phosphors.

  Among optically active metal elements M, a phosphor in which Ce, Eu, or Tb is dissolved is a high-luminance phosphor.

  A phosphor containing at least Li as the A element and at least Ce as the metal element M emits blue or green fluorescence having a peak at a wavelength in the range of 440 nm to 520 nm when irradiated with the excitation source. As an excitation source, it is efficiently excited by ultraviolet rays, visible light, electron beams, X-rays, or the like. When excited by ultraviolet light or visible light, it is excited efficiently particularly at a wavelength in the range of 230 nm to 400 nm. Since this phosphor emits light at a wavelength of 253.7 nm emitted from vacuum ultraviolet rays or mercury atoms, it is suitable for use in plasma displays, fluorescent lamps, and mercury lamps. Moreover, since it emits light efficiently by ultraviolet LED and purple LED, it is suitable for the use of white LED which uses these LED as an excitation source.

  A phosphor containing at least Li as the A element and at least Eu as the metal element M emits green or yellow fluorescence having a peak at a wavelength in the range of 500 nm to 570 nm when irradiated with the excitation source. The excitation source is efficiently excited by ultraviolet rays, electron beams, X-rays, and the like. When excited by ultraviolet light or visible light, it is excited efficiently at a wavelength in the range of 250 nm to 450 nm. Since this phosphor emits light at a wavelength of 253.7 nm emitted from vacuum ultraviolet rays or mercury atoms, it is suitable for use in plasma displays, fluorescent lamps, and mercury lamps. Moreover, since it emits light efficiently by the light emitted from the ultraviolet LED and the purple LED, it is suitable for use as a white LED using these LEDs as an excitation source.

When trivalent or divalent ions are added, the charge can be compensated in consideration of the valence of the metal ions. Since Ce ³⁺ and ^{Eu 2+} ions is considered to be replaced with ^{A +} of AAlSiON ₂ crystals, substituting Si in AAlSiON ₂ crystal to Al, or by substituting O to N, electroneutrality is maintained This stabilizes the crystal structure. Further, according to the method of substituting two A ⁺ ions with one divalent ion (for example, Eu ²⁺ ion) and the method of substituting three A ⁺ ions with one trivalent ion (for example, Ce ³⁺ ion), The electrical neutrality is maintained and the crystal structure is stabilized.

In the present invention, the amount of Si and Al and the amount of O and N can take a wide composition range. In particular, the composition of AAl _{1 + z} Si _1-z O _{1 + z} N _2−z (where 0 <z <0.5) is a stable solid solution crystal because the electrical neutrality is maintained, and the chemical stability is high.

Although the composition of the phosphor of the present invention is not particularly defined, it is represented by a composition formula M _{a Ab} Al _cS i _d O _e N _f (where a + b + c + d + e + f = 1), and parameters a, b, c, d , E, and f are preferable because the composition range selected from values satisfying all of the following conditions has high emission intensity.
0.00001 ≦ a ≦ 0.1
0.12 ≦ b ≦ 0.24
0.12 ≦ c ≦ 0.24
0.12 ≦ d ≦ 0.24
0.12 ≦ e ≦ 0.24
0.24 ≦ f ≦ 0.40

Here, a represents the amount of the metal ion M added as the emission center, and the atomic ratio is preferably 0.00001 or more and 0.1 or less. Here, when using 2 or more types of metal ions as M, a value represents the sum total of the addition amount of each metal ion. If the a value is smaller than 0.00001, the number of ions that become the emission center is small, and the emission luminance may be reduced. If it is larger than 0.1, there is a risk that the brightness is lowered due to concentration quenching due to interference between ions. b is the amount of element A, and it is preferable that the atomic ratio be 0.12 or more and 0.24 or less. If the b value is out of this range, the bonds in the crystal become unstable, and the generation rate of a crystal phase other than the AAlSiON ₂ crystal or the solid solution crystal increases, and the emission intensity may decrease. The element A is selected from the group consisting of Li, Na, and K as described above. c is the amount of Al element, and is preferably 0.12 to 0.24 in terms of atomic ratio. If the c value is out of this range, the generation ratio of crystal phases other than AAlSiON ₂ crystals or solid solution crystals increases, and the light emission intensity may be reduced. d is the amount of Si element, and the atomic ratio is preferably 0.12 or more and 0.24 or less. If the d value is out of this range, the generation rate of crystal phases other than AAlSiON ₂ crystals or solid solution crystals increases, and the light emission intensity may decrease. e is the amount of oxygen, and is preferably 0.12 to 0.24. If the e value is out of this range, the rate of generation of crystal phases other than AAlSiON ₂ crystals or solid solution crystals increases, and the light emission intensity may decrease. f is the amount of nitrogen, and is preferably set to be 0.24 or more and 0.40 or less. If the e value is out of this range, the rate of generation of crystal phases other than AAlSiON ₂ crystals or solid solution crystals increases, and the light emission intensity may decrease. Furthermore, as long as the crystal structure of the AAlSiON ₂ crystal or the solid solution crystal is not broken, fluorine, chlorine, or the like can be included as a nonmetallic ion.

  When the phosphor of the present invention is used as a powder, the average particle size is preferably 0.1 μm or more and 20 μm or less from the viewpoints of dispersibility in the resin and fluidity of the powder. Further, by making the powder into single crystal particles in this range, the emission luminance is further improved.

  Since the phosphor of the present invention emits light efficiently when excited with ultraviolet light or visible light having a wavelength of 100 nm to 450 nm, it is preferable for white LED applications. Furthermore, the phosphor of the present invention can be excited by an electron beam or an X-ray. In particular, electron beam excitation emits light more efficiently than other nitride phosphors, and therefore is preferable for use in electron beam excitation image display devices.

In the present invention, from the viewpoint of fluorescence emission, it is desirable that the constituent AAlSiON ₂ crystal or solid solution crystal contains a high purity and as much as possible. If possible, it is preferably composed of a single phase. It can also be composed of a mixture with other crystalline phase or amorphous phase. In this case, the content of AAlSiON ₂ crystals or solid solution crystals is preferably 10% by mass or more, more preferably 50% by mass or more in order to obtain high luminance. In the present invention, the main component has a content of AAlSiON ₂ crystals or solid solution crystals of at least 10% by mass. The content ratio can be obtained by performing X-ray diffraction measurement and conducting a Rietveld analysis on the AAlSiON ₂ crystal or solid solution crystal and other crystal phases. Simply, it can be determined from the ratio of the strength of the strongest peak of each phase for the AAlSiON ₂ crystal or solid solution crystal and the other crystal phase.

  In a phosphor composed of a mixture with another crystal phase or an amorphous phase, it can be a mixture with a conductive inorganic substance. When the phosphor of the present invention is excited with an electron beam in VFD, FED, etc., it is preferable to have a certain degree of conductivity so that electrons do not accumulate on the phosphor and escape to the outside. As the conductive substance, an oxide, an oxynitride, a nitride, or a mixture thereof containing one or more elements selected from Zn, Ga, In, and Sn can be given. Among these, indium oxide and indium-tin oxide (ITO) are preferable because they have little decrease in fluorescence intensity and high conductivity.

The phosphor of the present invention develops blue, green, or yellow depending on the composition, but if mixing with other colors is necessary, an inorganic phosphor that develops these colors may be mixed as necessary. Can do. Other inorganic phosphors that can be used include oxides, sulfides, oxysulfides, oxynitrides, and crystals based on nitride crystals, but the durability of the mixed phosphors is required. In this case, it is preferable to use oxynitride or nitride crystal as a host. As phosphors having oxynitride or nitride crystal as a host, α-sialon: Eu yellow phosphor, α-sialon: Ce blue phosphor, CaAlSiN ₃ : Eu and (Ca, Sr) AlSiN ₃ : Eu Red phosphor (with a portion of Ca of CaAlSiN ₃ crystal replaced with Sr), blue phosphor hosting the JEM phase (LaAl (Si _6-z Al _z ) N _10-z O _z ): Ce), Examples include La ₃ Si ₈ N ₁₁ O ₄ : Ce blue phosphor, AlN: Eu blue phosphor, and the like.

  The phosphor of the present invention has an excitation spectrum and a fluorescence spectrum that differ depending on the composition. By appropriately selecting and combining them, the phosphor can be set to have various emission spectra. What is necessary is just to set the aspect to the spectrum required based on a use.

  Although the manufacturing method of the fluorescent substance of this invention is not specifically limited, The following method can be mentioned as an example.

A starting material of metal element M (M is an element selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb) A raw material mixture containing at least a starting material of a metal element A (A is an element selected from the group consisting of Li, Na and K), an Al starting material, and an Si starting material, After filling the container with the relative bulk density kept at a filling rate of 40% (2/5) or less, in a nitrogen atmosphere of 1 × 10 ⁻¹ MPa or more and 1 × 10 ² MPa or less, 12 × 10 ² ° C. or more Firing is performed in a temperature range of 22 × 10 ² ° C. or lower. By doing in this way, the phosphor of the present invention in which at least M is dissolved in the AAlSiON ₂ crystal or solid solution crystal can be produced. The optimum firing temperature may vary depending on the composition, and can be optimized as appropriate. In general, it is preferable to fire in a temperature range of 14 × 10 ² ° C to 20 × 10 ² ° C. In this way, a high-luminance phosphor can be obtained. When the firing temperature is lower than 14 × 10 ² ° C., the production rate of AAlSiON ₂ crystals or solid solution crystals may be low. Moreover, when a calcination temperature exceeds 22 * 10 < ² > degreeC, a special apparatus will be needed and it is industrially unpreferable.

  The starting material of the metal element M is M metal, oxide, carbonate, nitride, fluoride, chloride, oxynitride, a compound containing M, or a combination thereof. For example, it is preferable to use manganese carbonate or manganese oxide when M is Mn, cerium oxide when M is Ce, and europium oxide when M is Eu. The compound containing M is, for example, an organic material such as an organic precursor containing M.

  The starting material of the metal element A is A metal, oxide, carbonate, nitride, fluoride, chloride, oxynitride, a compound containing A, or a combination thereof. For example, when A is Ca, it is preferable to use calcium carbonate or calcium oxide. The compound containing A is, for example, an organic material such as an organic precursor containing A.

  The Si starting material is a Si metal, oxide, carbonate, nitride, fluoride, chloride, oxynitride, Si-containing compound, or a combination thereof. Specifically, metal silicon, silicon oxide, silicon nitride, organic precursor containing silicon, silicon diimide, amorphous body obtained by heat treatment of silicon diimide, and the like can be used. If necessary, a mixture of silicon oxide and silicon nitride can be used. In addition to being able to obtain a highly pure synthetic product with high reactivity, these have the advantage that they are produced as industrial raw materials and are easily available. As silicon nitride, α-type, β-type, amorphous body, and a mixture thereof can be used.

  The starting material of Al is an Al metal, oxide, carbonate, nitride, fluoride, chloride, oxynitride, Al-containing compound, or a combination thereof. Specifically, metal aluminum, aluminum oxide, aluminum nitride, an organic precursor containing aluminum, or the like can be used. Usually, aluminum nitride and, if necessary, a mixture of aluminum nitride and aluminum oxide are preferably used. In addition to being able to obtain a highly pure synthetic product with high reactivity, these have the advantage that they are produced as industrial raw materials and are easily available.

  In order to improve the reactivity at the time of baking, the inorganic compound which produces | generates a liquid phase at the temperature below a calcination temperature can be added to the mixture of a starting material as needed. As the inorganic compound, those that generate a stable liquid phase at the reaction temperature are preferable, and fluoride, chloride, iodide, bromide, or phosphorus of Li, Na, K, Mg, Ca, Sr, Ba, and Al elements. Acid salts are suitable. Furthermore, these inorganic compounds may be added alone or in combination of two or more. Of these, calcium fluoride and aluminum fluoride are preferable because of their high ability to improve the reactivity of synthesis. However, when adding an inorganic compound that is a constituent element of the phosphor, it is necessary to pay attention to variations in the composition. The addition amount of the inorganic compound is not particularly limited, but the effect is particularly great when it is 0.1 to 10 parts by weight with respect to 100 parts by weight of the mixture of the metal compound as the starting material. When the amount is less than 0.1 parts by weight, the reactivity is not improved, and when the amount exceeds 10 parts by weight, the luminance of the phosphor may be lowered. When these inorganic compounds are added and baked, the reactivity is improved, grain growth is promoted in a relatively short time, and a single crystal having a large grain size grows, thereby improving the luminance of the phosphor.

The nitrogen atmosphere is preferably a gas atmosphere having a pressure range of 1 × 10 ⁻¹ MPa to 1 × 10 ² MPa. More preferably, it is 5 × 10 ⁻¹ MPa or more and 1 × 10 ¹ MPa or less. When silicon nitride is used as a raw material, heating to a temperature of 182 × 10 ¹ ° C. or higher in a nitrogen gas atmosphere lower than 1 × 10 ⁻¹ MPa is not preferable because the raw material is likely to be thermally decomposed. 10 MPa is sufficient, and if it exceeds 1 × 10 ² MPa, a special apparatus is required, which is not suitable for industrial production.

When a fine powder having a particle size of several μm is used as a starting material, the mixture of metal compounds after the mixing step is in a form in which fine powder having a particle size of several μm is aggregated to a size of several hundred μm to several mm (hereinafter referred to as “a”) Called "powder agglomerates"). In the present invention, the powder aggregate is fired in a state where the bulk density is maintained at a filling rate of 40% (2/5) or less. More preferably, the bulk density is 20% (1/5) or less. Here, the relative bulk density is a ratio of a value (bulk density) obtained by dividing the mass of the powder filled in the container by the volume of the container and the true density of the substance of the powder. In normal sialon production, a hot press method in which heating is performed while applying pressure or a production method in which baking is performed after mold forming (compacting) is used, but the firing at this time is performed with a high powder filling rate. . However, in the present invention, the powder powder aggregates having the same particle size without being mechanically applied to the powder or previously molded using a mold or the like are used as they are. Etc. are filled with a bulk density of 40% (2/5) or less. If necessary, the powder aggregate can be granulated to an average particle size of 5 × 10 ² μm or less using a sieve or air classification, and the particle size can be controlled. Further, it may be granulated directly into a shape of 5 × 10 ² μm or less using a spray dryer or the like. Further, when the container is made of boron nitride, there is an advantage that there is little reaction with the phosphor. When a boron nitride container is used, a boron component may be mixed into the product. However, it is preferable that the amount of boron mixed is within a range that does not deteriorate the light emission characteristics of the phosphor. In addition, since the emission wavelength and excitation wavelength can be changed by adding boron, boron may be added to the raw material depending on the application.

The reason for firing while maintaining the bulk density at 40% (2/5) or less is to fire in a state where there is a free space around the raw material powder. The optimum bulk density varies depending on the shape and surface state of the granular particles, but is preferably 20% (1/5) or less. In this way, the reaction product grows in a free space, so that the contact between the crystals is reduced and a crystal with few surface defects can be synthesized. Thereby, a fluorescent substance with high brightness is obtained. If the bulk density exceeds 40% (2/5), densification occurs partially during firing, resulting in a dense sintered body that hinders crystal growth and may reduce the brightness of the phosphor. Moreover, it is difficult to obtain a fine powder. Further, the size of the powder aggregate is particularly preferably 5 × 10 ² μm or less because of excellent grindability after firing.

  Next, a powder aggregate having a filling rate of 40% (2/5) or less is fired under the above conditions. The furnace used for firing may be a metal resistance heating method or a graphite resistance heating method because the firing temperature is high and the firing atmosphere is nitrogen. An electric furnace using carbon as the material for the high temperature part of the furnace is preferred. The firing is preferably performed by a firing method in which no mechanical pressure is applied from the outside, such as an atmospheric pressure sintering method or a gas pressure sintering method, in order to perform the firing while maintaining a bulk density in a predetermined range.

  When the powder aggregate obtained by firing is hard aggregated, it is pulverized by a pulverizer generally used industrially, such as a ball mill or a jet mill. Among these, ball milling makes it easy to control the particle size. The balls and pots used at this time are preferably made of a silicon nitride sintered body or a sialon sintered body. Grinding is performed until the average particle size becomes 20 μm or less. The average particle size is particularly preferably 20 nm or more and 10 μm or less. When the average particle diameter exceeds 20 μm, the fluidity of the powder and the dispersibility in the resin are deteriorated, and the light emission intensity becomes uneven depending on the part when the light emitting device is formed in combination with the light emitting element. When the thickness is less than 20 nm, the operability for handling the powder is deteriorated. If the desired particle size cannot be obtained only by grinding, classification can be combined. As a classification method, sieving, air classification, precipitation in a liquid, or the like can be used.

  Furthermore, by washing with a solvent that dissolves the inorganic compound after firing, the content of inorganic compounds other than phosphors such as glass phase, second phase, or impurity phase contained in the reaction product obtained by firing is reduced. As a result, the luminance of the phosphor is improved. As such a solvent, water and an aqueous solution of an acid can be used. As the acid aqueous solution, sulfuric acid, hydrochloric acid, nitric acid, hydrofluoric acid, a mixture of organic acid and hydrofluoric acid, or the like can be used. Of these, a mixture of sulfuric acid and hydrofluoric acid is highly effective. This treatment is particularly effective for a reaction product obtained by adding an inorganic compound that generates a liquid phase at a temperature lower than the firing temperature and firing at a high temperature.

Although a fine phosphor powder is obtained by the above steps, heat treatment is effective for further improving the luminance. In this case, the powder after firing or the powder after particle size adjustment by pulverization or classification can be heat-treated at a temperature of 10 × 10 ² ° C. or more and less than the firing temperature. At a temperature lower than 10 × 10 ² ° C., the effect of removing surface defects is small. Exceeding the firing temperature is not preferable because the pulverized powders adhere again. Although the atmosphere suitable for the heat treatment varies depending on the composition of the phosphor, one or two or more mixed atmospheres selected from nitrogen, air, ammonia, and hydrogen can be used. Particularly, the nitrogen atmosphere is effective for defect removal. It is preferable because it is excellent.

  The phosphor of the present invention obtained as described above is characterized by having high-luminance visible light emission comparable to ordinary oxide phosphors and existing sialon phosphors. Among these, specific compositions are characterized by emitting blue, blue-green, green, and yellow light, and are suitable for lighting fixtures and image display devices. In addition, since it does not deteriorate even when exposed to high temperatures, it has excellent heat resistance, and excellent long-term stability in an oxidizing atmosphere and moisture environment.

  The lighting fixture of this invention is comprised using the light emission light source and the fluorescent substance of this invention at least. Examples of lighting fixtures include LED lighting fixtures and fluorescent lamps. In LED lighting fixtures, the phosphor of the present invention is used to manufacture by a known method as described in JP-A-5-152609, JP-A-7-99345, JP-A-2927279, and the like. Can do. In this case, it is desirable that the light emission source emits ultraviolet light, purple light, or blue light having a wavelength of 330 to 480 nm, and among them, a blue LED light emitting element or an LD light emitting element of 380 to 420 nm purple or 440 nm to 470 nm is preferable.

  These light emitting elements include those made of nitride semiconductors such as GaN and InGaN, and can be light emitting light sources that emit light of a predetermined wavelength by adjusting the composition.

In addition to the method of using the phosphor of the present invention alone in a lighting fixture, a lighting fixture emitting a desired color can be configured by using it together with a phosphor having other light emission characteristics. As an example of this, there is a combination of a 330-420 nm ultraviolet LED or LD light emitting element, a yellow phosphor excited at this wavelength and having an emission peak at a wavelength of 550 nm to 600 nm, and the blue phosphor of the present invention. As such a yellow phosphor, α-sialon: Eu ²⁺ described in JP-A No. 2002-363554 and (Y, Gd) ₂ (Al, Ga) ₅ O ₁₂ described in JP-A No. 9-218149: Ce can be mentioned. In this configuration, when the phosphors are irradiated with ultraviolet rays emitted from the LED or LD, light of two colors, blue and yellow, is emitted, and a white luminaire is obtained by mixing them.

As another example, an ultraviolet LED or LD light emitting device of 330 to 420 nm, the green phosphor of the present invention having an emission peak at a wavelength of 520 nm to 550 nm and an emission peak at a wavelength of 590 nm to 700 nm. There is a combination of a red phosphor having the above and the blue phosphor of the present invention. Examples of such a red phosphor include CaSiAlN ₃ : Eu described in International Publication No. 2005/052087 pamphlet. In this configuration, when the phosphors are irradiated with ultraviolet rays emitted from the LED or LD, light of three colors of red, green, and blue is emitted, and a white lighting device is obtained by mixing these.

  The image display device of the present invention is composed of at least an excitation source and the phosphor of the present invention, such as a fluorescent display tube (VFD), a field emission display (FED or SED), a plasma display panel (PDP), a cathode ray tube (CRT), etc. There is. The phosphor of the present invention has been confirmed to emit light by excitation of vacuum ultraviolet rays of 100 to 190 nm, ultraviolet rays of 190 to 380 nm, electron beams, etc., and in combination of these excitation sources and the phosphor of the present invention, An image display apparatus as described above can be configured.

  Since the phosphor of the present invention has excellent excitation efficiency of electron beams, it is suitable for VFD, FED, SED, and CRT applications that are used at an acceleration voltage of 10 V or more and 30 kV or less.

  The FED is an image display device that emits light by accelerating electrons emitted from a field emission cathode and colliding with a phosphor applied to the anode, and is required to emit light at a low acceleration voltage of 5 kV or less. By combining these phosphors, the light emission performance of the display device is improved.

  Next, the present invention will be described in more detail with reference to the following examples, which are disclosed as an aid for easy understanding of the present invention, and the present invention is limited to these examples. It is not a thing.

In Examples 1 to 4, the raw material powder was a specific surface area of 3.3 m ² / g, an oxygen content of 0.79% aluminum nitride powder (F grade made by Tokuyama), an average particle size of 0.5 μm, oxygen Silicon nitride powder with a content of 0.93% by weight, α-type content of 92%, silicon dioxide powder with a purity of 99.99% (high purity chemical reagent grade), lithium carbonate powder with a purity of 99.9% (high purity chemical) Reagent grade) and, if necessary, 99.9% pure europium oxide powder, cerium oxide powder and terbium oxide powder (manufactured by Shin-Etsu Chemical).

<Example 1>
First, in order to synthesize LiAlSiON ₂ of theoretical _{composition, Li 2 CO 3, AlN,} Si 3 N 4, SiO 2 molar ratio _{Li 2 CO 3: AlN: Si} 3 N 4: SiO 2 is 2: 4: Weighing so as to have a composition of 1: 1, mixing using a silicon nitride mortar and pestle, and then putting into a boron nitride crucible having a diameter of 20 mm and a height of 20 mm, and a graphite resistance heating type electric furnace Set. In the firing operation, first, the firing atmosphere is evacuated by a diffusion pump, heated from room temperature to 800 ° C. at a rate of 500 ° C. per hour, nitrogen at a temperature of 800.degree. The pressure was 5 MPa, the temperature was raised to 1700 ° C. at 500 ° C. per hour, and the temperature was maintained at 1700 ° C. for 4 hours. Calcined powder was pulverized using a mortar and pestle made of silicon nitride, it was subjected to powder X-ray diffraction measurement using a K _alpha line Cu (XRD). As a result, as shown in FIG. 1, the generation of substantially single-phase LiAlSiON ₂ was confirmed.

  Analysis of X-ray diffraction data revealed that this crystal could be indexed in the orthorhombic system. The indexing results are shown in Table 1. The lattice constant indexed with orthorhombic crystal was a = 0.91375 nm, b = 0.53974 nm, and c = 0.48896. From the results of X-ray diffraction and electron beam diffraction, this crystal is Cmc21 (International Tables for Crystallography No. 36 space group). Further, the atomic coordinate positions of each element determined by Rietveld analysis using this space group are as shown in Table 2. The calculated intensities calculated by the Rietveld method from the measured intensities of X-ray diffraction and atomic coordinates are in good agreement as shown in FIG.

Table 1 shows the indexing results for LiAlSiON ₂ crystals.

Table 2 shows the lattice constants and atomic coordinate positions of the LiAlSiON ₂ crystal.

A schematic diagram of the crystal structure obtained by the Rietveld method is shown in FIG. This crystal has a skeleton similar to Si ₂ N ₂ O crystal (mineral name soite) or CaAlSiN ₃ crystal. That is, Li occupies the Ca position of the CaAlSiN ₃ crystal and O occupies a part of the N position, and has a structure in which atomic coordinates are changed as the elements are different. When M ions are added to this crystal, it is considered that Li ions are substituted and M ions are taken into the crystal.

  Using the VASP (Vienna Ab-initio Simulation Package) code based on the space group, lattice constant, and atomic coordinate data in Table 1, the stable structure of the crystal was calculated by the first principle calculation method. A value close to the result was obtained. This confirmed the validity of Rietveld analysis and the crystal structure of FIG.

<Example 2>
A phosphor containing the metal element Eu was synthesized. In the design composition formula Eu _0.005 Li _0.99 Al ₁ Si ₁ O ₁ N ₂ (Eu _0.000834 Li _0.165 Al _0.167 Si _0.167 O _0.167 N _0.333 ) shown in Table 3 In order to obtain the compounds shown, the raw material powders are weighed at a mass ratio shown in Table 4 and mixed using a mortar and pestle made of a silicon nitride sintered body, and then passed through a sieve having a mesh opening of 125 μm, which is excellent in fluidity. A powder aggregate was obtained. Here, as for the amount of Eu for substituting Li, 1% of Li was replaced with 0.5% of Eu in consideration of the valence. When this powder aggregate was naturally dropped into a boron nitride crucible having a diameter of 20 mm and a height of 20 mm, the bulk density was 15 to 30% by volume. The bulk density was calculated from the weight of the charged powder aggregate, the inner volume of the crucible, and the true density of the powder. Next, the crucible was set in a graphite resistance heating type electric furnace. In the firing operation, first, the firing atmosphere is evacuated by a diffusion pump, heated from room temperature to 800 ° C. at a rate of 500 ° C. per hour, nitrogen at a temperature of 800.degree. The pressure was 5 MPa, the temperature was raised to 1700 ° C. at 500 ° C. per hour, and the temperature was maintained at 1700 ° C. for 4 hours. The synthesized sample was ground with a mortar and pestle made of silicon nitride, and by performing powder X-ray diffraction measurement using a K _alpha line Cu (XRD), the same pattern as FIG. 1, LiAlSiON ₂ crystal or Formation of the solid solution was confirmed.

Table 3 shows the design composition formulas of Examples 2 to 4.

Table 4 shows the mixed composition of the raw material powders of Examples 2 to 4.

  As a result of irradiating the powder thus obtained with a lamp emitting light having a wavelength of 365 nm, it was confirmed that the powder emitted blue-green light. The emission spectrum and excitation spectrum of this powder were measured using a fluorescence spectrophotometer model F4500 manufactured by Hitachi High-Technologies. FIG. 4 shows an excitation spectrum and an emission spectrum. The synthetic powder was found to be a phosphor that emits light having an excitation band at a wavelength in the range of 250 to 420 nm and having an emission spectrum peak at 530 nm. The excitation spectrum was measured by monitoring emission at 530 nm. The emission spectrum was measured with 310 nm excitation light. In addition, since the emission intensity (count value) of the excitation spectrum and the emission spectrum varies depending on the measurement apparatus and conditions, the unit is an arbitrary unit. That is, the comparison can be made only within the present embodiment measured under the same conditions.

  The light emission characteristics (cathode luminescence, CL) when irradiated with an electron beam were observed with an SEM equipped with a CL detector, and a CL image was evaluated. This device detects visible light generated by irradiating an electron beam and obtains it as a photographic image that is two-dimensional information, thereby clarifying which wavelength of light is emitted at which location. . By observation of the emission spectrum, it was confirmed that this phosphor was excited by an electron beam and emitted blue-green light. In addition, since the emitted light intensity by this measurement changes with a measuring apparatus and measurement conditions, a unit is arbitrary units.

<Example 3>
A phosphor containing the metal element Ce was synthesized. In the design composition formula Ce _0.005 Li _0.985 Al ₁ Si ₁ O ₁ N ₂ shown in Table 3 (Ce _0.000835 Li _0.164 Al _0.167 Si _0.167 O _0.167 N _0.334 ) In order to obtain the compounds shown, the raw material powders are weighed at a mass ratio shown in Table 4 and mixed using a mortar and pestle made of a silicon nitride sintered body, and then passed through a sieve having a mesh opening of 125 μm, which is excellent in fluidity. A powder aggregate was obtained. Here, as for the amount of Ce substituting Li, 1.5% of Li was replaced with 0.5% of Ce in consideration of the valence. When this powder aggregate was naturally dropped into a boron nitride crucible having a diameter of 20 mm and a height of 20 mm, the bulk density was 15 to 30% by volume. The bulk density was calculated from the weight of the charged powder aggregate, the inner volume of the crucible, and the true density of the powder. Next, the crucible was set in a graphite resistance heating type electric furnace. In the firing operation, first, the firing atmosphere is evacuated by a diffusion pump, heated from room temperature to 800 ° C. at a rate of 500 ° C. per hour, nitrogen at a temperature of 800.degree. The pressure was 5 MPa, the temperature was raised to 1700 ° C. at 500 ° C. per hour, and the temperature was maintained at 1700 ° C. for 4 hours. The synthesized sample was ground using mortar and pestle made of silicon nitride, and by performing powder X-ray diffraction measurement using a K _alpha line Cu (XRD), the same pattern as FIG. 1, LiAlSiON ₂ crystal or Formation of the solid solution was confirmed.

  As a result of irradiating the powder thus obtained with a lamp emitting light having a wavelength of 365 nm, it was confirmed that the powder emitted blue-green light. The emission spectrum and excitation spectrum of this powder were measured using a fluorescence spectrophotometer model F4500 manufactured by Hitachi High-Technologies. FIG. 5 shows an excitation spectrum and an emission spectrum. It was found that the synthetic powder is a phosphor that emits light having an excitation band at a wavelength in the range of 250 to 420 nm and having an emission spectrum peak at 475 nm. The excitation spectrum was measured by monitoring emission at 475 nm. The emission spectrum was measured with two types of excitation light of 315 nm and 350 nm. In addition, since the emission intensity (count value) of the excitation spectrum and the emission spectrum varies depending on the measurement apparatus and conditions, the unit is an arbitrary unit. That is, the comparison can be made only within the present embodiment measured under the same conditions.

<Example 4>
A phosphor containing the metal element Tb was synthesized. In the compositional formula Tb _0.005 Li _0.985 Al ₁ Si ₁ O ₁ N ₂ (Tb _0.000835 Li _0.164 Al _0.167 Si _0.167 O _0.167 N _0.334 ) shown in Table 3 In order to obtain the compounds shown, the raw material powders are weighed at a mass ratio shown in Table 4 and mixed using a mortar and pestle made of a silicon nitride sintered body, and then passed through a sieve having a mesh opening of 125 μm, which is excellent in fluidity. A powder aggregate was obtained. Here, the amount of Tb substituting Li was such that 1.5% of Li was replaced with 0.5% of Tb in consideration of the valence. When this powder aggregate was naturally dropped into a boron nitride crucible having a diameter of 20 mm and a height of 20 mm, the bulk density was 15 to 30% by volume. The bulk density was calculated from the weight of the charged powder aggregate, the inner volume of the crucible, and the true density of the powder. Next, the crucible was set in a graphite resistance heating type electric furnace. In the firing operation, first, the firing atmosphere is evacuated by a diffusion pump, heated from room temperature to 800 ° C. at a rate of 500 ° C. per hour, nitrogen at a temperature of 800.degree. The pressure was 5 MPa, the temperature was raised to 1700 ° C. at 500 ° C. per hour, and the temperature was maintained at 1700 ° C. for 4 hours. The synthesized sample was ground with a mortar and pestle made of silicon nitride, and by performing powder X-ray diffraction measurement using a K _alpha line Cu (XRD), the same pattern as FIG. 1, LiAlSiON ₂ crystal or Formation of the solid solution was confirmed.

  As a result of irradiating the powder thus obtained with a lamp emitting light having a wavelength of 254 nm, it was confirmed that the powder emitted green light. The emission spectrum and excitation spectrum of this powder were measured using a fluorescence spectrophotometer model F4500 manufactured by Hitachi High-Technologies. FIG. 6 shows an excitation spectrum and an emission spectrum. The synthetic powder was found to be a phosphor that emits light having an excitation band at a wavelength in the range of 200 to 380 nm and having an emission spectrum peak at 542 m. The excitation spectrum was measured by monitoring emission at 542 nm. The emission spectrum was measured with two types of excitation light of 235 nm and 303 nm. In addition, since the emission intensity (count value) of the excitation spectrum and the emission spectrum varies depending on the measurement apparatus and conditions, the unit is an arbitrary unit. That is, the comparison can be made only within the present embodiment measured under the same conditions.

<Example 5>
Next, the lighting fixture using the phosphor of the present invention will be described. In FIG. 7, the schematic structural drawing of white LED as a lighting fixture is shown. The phosphor mixture made of the nitride of the present invention and other phosphors and a violet LED chip 2 having a wavelength of 405 nm are used as a light emitting element. The blue-green phosphor of Example 2 of the present invention and Ca-α-sialon having a composition of Ca _0.75 Eu _0.25 Si _8.625 A1 _3.375 O _1.125 N _14.875 : yellow of Eu A mixture phosphor 1 in which a phosphor and a red phosphor of CaAlSiN ₃ : Eu are dispersed in a resin layer is placed on the LED chip 2 and placed in a container 7. When a current is passed through the conductive terminals 3 and 4, a current is supplied to the LED chip 2 through the wire bond 5 to emit light of 440 nm, and this light is a mixture of a green phosphor, a yellow phosphor and a red phosphor. The phosphor 1 is excited to emit green, yellow, and red light, respectively, and the blue light from the LED chip 2 is mixed to function as an illumination device that emits white light.

<Example 6>
Next, a design example of an image display device using the nitride phosphor of the present invention will be described. FIG. 8 is a principle schematic diagram of a plasma display panel as an image display device. The red phosphor (Y (PV) O ₄ : Eu) 8, the green phosphor 9 of Example 4 of the present invention, and the blue phosphor (BaMgAl ₁₀ O ₁₇ : Eu) 10 are included in the respective cells 11, 12, 13. It is applied to the inner surface. When the electrodes 14, 15, 16, and 17 are energized, vacuum ultraviolet rays are generated by Xe discharge in the cell, thereby exciting the phosphors to emit red, green, and blue visible light, and this light is emitted from the protective layer 20, It is observed from the outside through the dielectric layer 19 and the glass substrate 22 and functions as an image display.

<Example 7>
FIG. 9 is a schematic diagram showing the principle of a field emission display panel as an image display device. The green phosphor of Example 4 of the present invention is applied to 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 of the anode 53 and the cathode, collide with the phosphor 56, and the phosphor emits 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, a display that can produce a variety of colors is formed by arranging a large number of blue and red cells in addition to green. The Although it does not specify in particular about the fluorescent substance used for a blue or red cell, what emits high brightness | luminance with a low-speed electron beam is good to use.

  The phosphor of the present invention emits fluorescence having intensity comparable to that of the conventional phosphor by using a host crystal different from the conventional sialon phosphor and oxynitride phosphor. In particular, a phosphor having a specific composition emits blue, blue-green, green and yellow light. Since it is a phosphor made of a host crystal different from the conventional one, selection according to the application is possible. Furthermore, since the luminance of the phosphor is not significantly lowered when exposed to an excitation source, the phosphor is suitably used for VFD, FED, PDP, CRT, white LED, and the like. In the future, it is expected to contribute greatly to industrial development by being widely used in various electron beam excitation display devices.

X-ray diffraction chart of pure LiAlSiON ₂ . Comparison between the measured values in FIG. 1 and Rietveld analysis. Schematic diagram of the crystal structure of LiAlSiON _2. The excitation spectrum and emission spectrum by the fluorescence measurement of Example 2. The excitation spectrum and emission spectrum by the fluorescence measurement of Example 3. The excitation spectrum and emission spectrum by the fluorescence measurement of Example 4. Schematic of the lighting fixture (LED lighting fixture) by this invention. 1 is a schematic view of an image display device (plasma display panel) according to the present invention. 1 is a schematic view of an image display device (field emission display) according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mixture of blue-green phosphor of the present invention (Example 2), yellow phosphor and red phosphor 2 LED chip 3, 4 Conductive terminal 5 Wire bond 6 Resin layer 7 Container 8 Red phosphor 9 Green phosphor 10 Blue phosphor 11, 12, 13 UV light emitting cell 14, 15, 16, 17 Electrode 18, 19 Dielectric layer 20 Protective layer 21, 22 Glass substrate 51 Glass 52 Cathode 53 Anode 54 Gate 55 Emitter 56 Phosphor 57 Electron

Claims (10)

An AAlSiON ₂ crystal that emits fluorescence by excitation energy from an excitation source (where A is an element selected from at least one selected from the group consisting of Li, Na, and K) or a solid solution crystal of AAlSiON _2. In addition, the AAlSiON ₂ crystal or the solid solution crystal of AAlSiON ₂ includes at least M element (where M is Mn, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb). And a phosphor containing at least one element selected from the group. The phosphor according to claim 1, the crystal structure of the AAlSiON ₂ crystal or AAlSiON ₂ solid solution crystal is characterized by having the same crystal structure as the crystal structure of LiAlSiON ₂ crystals.   The phosphor according to claim 1, wherein the element A is Li.   2. The phosphor according to claim 1, wherein the element A contains at least Li, the element M contains at least Ce, and emits fluorescence having a peak in a wavelength range of 440 nm to 520 nm by the excitation energy. It is characterized by doing.   2. The phosphor according to claim 1, wherein the element A includes at least Li, the element M includes at least Eu, and the excitation energy emits fluorescence having a peak in a wavelength range of 500 nm to 570 nm. It is characterized by doing. 2. The phosphor according to claim 1, wherein the phosphor is represented by a composition formula M _a A _b Al _{c S} i _d O _e N _f (where a + b + c + d + e + f = 1), and parameters a, b , C, d, e, f are
0.00001 ≦ a ≦ 0.1 (i)
0.12 ≦ b ≦ 0.24 (ii)
0.12 ≦ c ≦ 0.24 (iii)
0.12 ≦ d ≦ 0.24 (iv)
0.12 ≦ e ≦ 0.24 (v)
0.24 ≦ f ≦ 0.40 (vi)
It is characterized by satisfying the above conditions.   M metal, oxide, carbonate, nitride, fluoride, chloride, oxynitride, a compound containing M or a combination thereof, and A metal, oxide, carbonate, nitride, fluoride, chloride Oxides, oxynitrides, compounds containing A or combinations thereof, Al metals, oxides, carbonates, nitrides, fluorides, chlorides, oxynitrides, compounds containing Al or combinations thereof, and Si A raw material mixture containing at least a metal, an oxide, a carbonate, a nitride, a fluoride, a chloride, an oxynitride, a compound containing Si, or a combination thereof was maintained at a filling ratio of a relative bulk density of 40% or less. 2. The method for producing a phosphor according to claim 1, wherein the phosphor is fired in a temperature range of 1200 ° C. or more and 2200 ° C. or less in a nitrogen atmosphere of 0.1 MPa or more and 100 MPa or less after filling the container in a state.   A lighting device comprising an excitation source and a phosphor that emits fluorescence by excitation light therefrom, wherein the excitation source emits excitation light having a wavelength of 330 to 420 nm, and at least a part of the phosphor is The lighting fixture which is the fluorescent substance in any one of Claims 1-6.   An image display device comprising an excitation source and a phosphor that emits fluorescence by excitation energy therefrom, wherein at least a part of the phosphor is the phosphor according to claim 1. apparatus.   The image display device according to claim 9, wherein the image display device is any one of a fluorescent display tube (VFD), a field emission display (FED or SED), or a cathode ray tube (CRT), and the excitation source is It is an electron beam having an acceleration voltage of 10 V to 30 kV.