JP2009167328A - Phosphor, method for producing it, and light emission apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a phosphor consisting of materials different from those of conventional rare earth-activated sialon phosphor and oxide phosphor. <P>SOLUTION: The phosphor includes AAl<SB>2</SB>Si<SB>5</SB>O<SB>2</SB>N<SB>8</SB>crystal (A is Mg, Ca, Sr, Ba or Zn) or its solid solution crystal in which metal ions M (M is at least one selected from Mn, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Tm, and Yb) is solid-soluted. The phosphor emits fluorescent light having a peak at a wavelength ranging from 450-700 nm. The phosphor is produced when a raw material mixture comprising metals, oxides, carbonates, nitrides, and the like of A, Al, and Si respectively is burnt at 1,200-2,200°C in a nitrogen atmosphere. The phosphor is used for luminaire and an image display device. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to an AAl ₂ Si ₅ O ₂ N ₈ crystal (where A is at least one selected from Mg, Ca, Sr, Ba, and Zn), or a phosphor having a solid solution crystal as a base crystal. And its manufacturing method and its application. More specifically, the application relates to a lighting apparatus and a light emitting apparatus for an image display device that utilize the property of the phosphor, that is, the property of emitting light having a peak at a wavelength of 300 nm to 700 nm.

  The phosphor is a fluorescent display tube (VFD (Vacuum-Fluorescent Display)), a field emission display (FED (Field Emission Display)), or an SED (Surface-Conduction 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 make the phosphor emit light, it is necessary to supply the phosphor with energy for exciting the phosphor, and the phosphor is not limited to vacuum ultraviolet rays, ultraviolet rays, electron beams, blue light, etc. 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 phosphors such as conventional silicate phosphors, phosphate phosphors, aluminate phosphors, and sulfide phosphors. For example, phosphors based on inorganic crystals containing nitrogen in the crystal structure, such as nitride phosphors, have been proposed.

An example of this 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). And is fired by a hot press method (for example, see 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 International Publication No. 2006/016711 Pamphlet Meghan L. Caldwell, et al., “Visible Luminescent Activation of Amorphous AIN: Eu Thin-Film Phosphorus with Osygen,” MRS Internet Journal Nitride, 6th page, 1st. 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, conventional phosphors using oxynitride as a host are insulating materials, and even when irradiated with an electron beam, the emission intensity is low, and the electron beam excitation is high for electron beam-excited image display devices such as FED. There is a need for phosphors that emit light with high brightness. 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 to provide a phosphor made of a material different from conventional rare earth activated sialon phosphors and oxide phosphors. Furthermore, it is intended to provide a phosphor powder that emits light efficiently with an electron beam.

In the present inventors, under such circumstances, AAl ₂ Si ₅ O ₂ N ₈ crystal (where A element is at least one element selected from the group consisting of Mg, Ca, Sr, Ba and Zn). Focusing on AAl ₂ Si ₅ O ₂ N ₈ crystal or AAl ₂ Si ₅ O ₂ N ₈ solid solution crystal, at least metal ions M (where M is Mn, Ce, Pr, Nd, Sm, Eu) , Gd, Tb, Dy, Ho, Er, Tm, and Yb, which are at least one element selected from the group consisting of oxynitrides in solid solution. It has been found that those having a specific solid solution state and a specific crystal phase become a phosphor having an emission peak at a wavelength in the range of 300 nm to 700 nm. Among them, those with a specific composition range in which Ca as an A element and Ce as an M element are in a solid solution have light emission of blue to green with high luminance by excitation with ultraviolet rays or electron beams, and are excited by illumination applications or electron beams. It was found to be suitable for an image display device. Furthermore, those having a specific composition range in which Ca as the A element and Eu as the M element are in a solid solution have a light emission of yellow to red with high luminance when excited by ultraviolet rays or electron beams, and are excited by illumination applications or electron beams. It was found to be suitable for an image display device.

  According to Patent Documents 1 to 9 and Non-Patent Documents 3 to 3, it has been reported that phosphors can be obtained by adding optically active ions such as Eu and Ce ions using nitride or oxynitride ceramics as host crystals. It is known that the excitable wavelength and emission wavelength are different depending on the type of host crystal and the optically active ion to be added, and the use is different.

The AAl ₂ Si ₅ O ₂ N ₈ crystal was found for the first time by the present inventor, and the AAl ₂ Si ₅ O ₂ N ₈ crystal or solid solution crystal in which optically active ions are solid-solved is an ultraviolet ray, visible light or electron. The important discovery that it can be used as a phosphor having high-luminance emission when excited by X-rays or X-rays 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) The phosphor of Invention 1 is an AAl ₂ Si ₅ O ₂ N ₈ crystal (where A element is at least one element selected from the group consisting of Mg, Ca, Sr, Ba and Zn) ) Or a solid solution crystal of AAl ₂ Si ₅ O ₂ N ₈ and M element (where M is Mn, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb) And at least one element selected from the group consisting of:
(Invention 2) The phosphor according to Invention 1, wherein the AAl ₂ Si ₅ O ₂ N ₈ is CaAl ₂ Si ₅ O ₂ N ₈ .
(Invention 3) The phosphor according to Invention 1, wherein Ca is contained as the A element, Eu is contained as the M element, and a peak is observed in a wavelength range of 550 nm to 700 nm by irradiating an excitation source. It emits the fluorescence which it has.
(Invention 4) The phosphor according to Invention 1, which includes Ca as the A element, Ce as the M element, and irradiation with an excitation source, thereby causing a peak in a wavelength range of 450 nm to 550 nm. It emits the fluorescence which it has.
(Invention 5) The phosphor according to Invention 4, further comprising Li.
(Invention 6) The phosphor according to Invention 1, wherein Zn is included as the A element, Eu is included as the M element, and an excitation source is irradiated to cause a peak in a wavelength range of 500 nm to 600 nm. It emits the fluorescence which it has.
(Invention 7) The phosphor according to Invention 1, comprising Sr as the A element, Eu as the M element, and having a peak in a wavelength range of 450 nm or more and 550 nm or less when irradiated with an excitation source. It emits fluorescence.
(Invention 8) The phosphor according to Invention 1, wherein Ba is contained as the A element, Eu is contained as the M element, and irradiation with an excitation source causes a peak in a wavelength range from 450 nm to 550 nm. It emits the fluorescence which it has.
(Invention 9) The phosphor according to Invention 1, wherein the composition formula M _a A _b Al _c Si _{d Le} O _f N _g (where L is a metal element other than M, A, Al, Si, a formula A + b + c + d + e + f + g = 1), and the parameters a, b, c, d, e, f and g are
0.00001 ≦ a ≦ 0.05
0.045 ≦ b ≦ 0.065
0.09 ≦ c ≦ 0.13
0.25 ≦ d ≦ 0.30
0 ≦ e ≦ 0.20
0.09 ≦ f ≦ 0.13
0.35 ≦ g ≦ 0.55
It is characterized by satisfying the above conditions.
(Invention 10) The phosphor according to the invention 1, is represented by a composition formula _{M x A 1-x Al 2} -y Si 5 + y O 2-y N 8 + y, parameter x, y is
0.00018 ≦ x ≦ 0.5
-2 ≦ y ≦ 1.5
It satisfies the following conditions.
(Invention 11) The method of Invention 11 for producing the phosphor according to Invention 1 includes M metal, oxide, carbonate, nitride, fluoride, chloride, oxynitride, a compound containing M, or A combination thereof, and a metal, oxide, carbonate, nitride, fluoride, chloride, oxynitride of A, a compound containing A, or a combination thereof, and a metal, oxide, carbonate of Al, Nitrides, fluorides, chlorides, oxynitrides, compounds containing Al, or combinations thereof, and Si metals, oxides, carbonates, nitrides, fluorides, chlorides, oxynitrides, Si 1200 ° C. in a nitrogen atmosphere of 0.1 MPa or more and 100 MPa or less after filling a container with a raw material mixture containing at least a compound containing them or a combination thereof in a state where the relative bulk density is maintained at a filling rate of 40% or less. Above 2200 ° C And firing in circumference.
(Invention 12) A lighting fixture according to Invention 12 includes a light emitting source that emits light having a wavelength of 330 to 470 nm and a phosphor, and the phosphor includes the phosphor according to Invention 1.
(Invention 13) The lighting apparatus according to Invention 12, wherein the light emission source includes an LED or an LD, and the phosphor further includes a green phosphor having an emission peak at a wavelength of 520 nm to 570 nm. To do.
(Invention 14) An image display device according to Invention 14 includes an excitation source and a phosphor, and the phosphor includes the phosphor according to Invention 1.
(Invention 15) The image display device according to Invention 14, wherein the image display device is 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 an AAl ₂ Si ₅ O ₂ N ₈ crystal in which a metal ion serving as an emission center is dissolved, or a solid solution crystal phase thereof as a main component, so that the emission intensity at 450 nm to 700 nm can be obtained. It is high and excellent as a phosphor for use in white LEDs. 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. Since the host crystal of the phosphor of the present invention is different from the conventional sialon phosphor or oxynitride phosphor, it is advantageous that the material can be appropriately selected according to the application.

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

The phosphor of the present invention can contain an AAl ₂ Si ₅ O ₂ N ₈ crystal or an AAl ₂ Si ₅ O ₂ N ₈ solid solution crystal as a main component. Here, the A element is at least one element selected from the group consisting of Mg, Ca, Sr, Ba and Zn. AAL The ₂ Si ₅ O ₂ N ₈ crystal solid solution _{crystal, AAl 2 Si 5 O 2 N} 8 remains oxygen / nitrogen ratio was maintained the crystal structure of crystals may change, A, Al, Si, O , N elemental Is a crystal in which other elements are substituted or other elements are added. Examples of addition of other elements include Li, Na, Sc, Y, La, Lu, B, Ga, C, Ge, P, S, F, and Cl. Due to the solid solution, AAl ₂ Si ₅ O ₂ N ₈ retains the structure of AAl ₂ Si ₅ O ₂ N ₈ crystal, and some or all of A, Al, Si, O, and N are replaced with other elements. The

The AAl ₂ Si ₅ O ₂ N ₈ crystal or the AAl ₂ Si ₅ O ₂ N ₈ solid solution crystal can be identified by X-ray diffraction or neutron diffraction. The details of the crystal structure are described in this specification, and the crystal structure and the X-ray diffraction pattern are uniquely determined from the lattice constant, space group, and atomic position data described therein. In addition to pure AAl ₂ Si ₅ O ₂ N ₈ crystal, a crystal whose lattice constant is changed by replacing the constituent element with another element is also included as part of the present invention.

FIG. 1 shows an X-ray diffraction pattern of an AAl ₂ Si ₅ O ₂ N ₈ crystal (provided that the A element is Ca).
FIG. 1 shows an X-ray diffraction pattern of a pure AAl ₂ Si ₅ O ₂ N ₈ crystal to which an optically active metal element M described later is not added. When the hexagonal crystal is indexed, the lattice constants are a = 0.79045 nm, c = 0.57381 nm, and have a space group of P31c, P-31C, P63mc, P-62c, and P63 / mmc. Moreover, this substance can be indexed even with orthorhombic crystals within the range of measurement error, and the lattice constants in that case are a = 0.574427 nm, b = 0.68481 nm, and c = 0.39540 nm.

In the present invention, the above _AAl 2 _Si 5 _O 2 _{N 8} crystal or _AAl 2 _Si 5 _O 2 _{N 8} solid solution crystal as a host crystal, which optically active metal element M (however, M is, Mn, Ce, Pr , Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb). Become a body. Among the AAl ₂ Si ₅ O ₂ N ₈ crystals, a phosphor having an A element as Ca, that is, a CaAl ₂ Si ₅ O ₂ N ₈ crystal as a base is a high-luminance phosphor.
Further, a phosphor in which the metal element M is Ce or Eu is a high-luminance phosphor.

A phosphor containing Eu as the metal element M emits yellow-green, yellow, orange, or red fluorescence having a peak in a wavelength range of 550 nm to 700 nm when irradiated with an excitation source. As an excitation source, it is efficiently excited by ultraviolet rays, visible light, electron beams, X-rays, or the like. In the case of excitation with ultraviolet light or visible light, excitation is efficiently performed particularly at a wavelength in the range of 230 nm to 500 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. In addition, when excited by visible light, it emits light efficiently, particularly with light having a wavelength in the range of 380 nm to 450 nm, specifically, light emitted from an ultraviolet LED, a purple LED (405 nm), and a blue LED (450 nm). It is suitable for the use of white LED or colored LED using these LEDs as an excitation source. Among them, the phosphor in which Eu is dissolved in CaAl ₂ Si ₅ O ₂ N ₈ is excited efficiently at a wavelength around 450 nm and emits orange light. Therefore, when a blue LED and this phosphor are combined, the color temperature is increased. Low bulb color LED can be made.

  A phosphor containing Zn as the A element and Eu as the M element emits green or yellow fluorescence having a peak in a wavelength range of 500 nm to 600 nm when irradiated with an excitation source. As an excitation source, it is efficiently excited by ultraviolet rays, visible light, electron beams, X-rays, or the like. In the case of excitation with ultraviolet light or visible light, excitation is efficiently performed particularly at a wavelength in the range of 230 nm to 500 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. In addition, since the light emitted from the ultraviolet LED, the purple LED, and the blue LED is efficiently emitted, it is suitable for a white LED or a colored LED using these LEDs as an excitation source. Especially, since it is excited efficiently at a wavelength around 450 nm, a white LED can be made by combining a blue LED and the present phosphor.

  A phosphor containing Sr as the A element and Eu as the M element emits blue or green fluorescence having a peak at a wavelength in the range of 450 nm to 550 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. In the case of excitation with ultraviolet light or visible light, excitation is efficiently performed particularly at a wavelength in the range of 230 nm to 500 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. In addition, since the light emitted from the ultraviolet LED, the purple LED, and the blue LED is efficiently emitted, it is suitable for a white LED or a colored LED using these LEDs as an excitation source. Especially, since it is excited efficiently at a wavelength around 405 nm, a white LED can be made by combining a purple LED and the present phosphor.

  A phosphor containing Ba as the A element and Eu as the M element emits blue or green fluorescence having a peak at a wavelength in the range of 450 nm to 550 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. In the case of excitation with ultraviolet light or visible light, excitation is efficiently performed particularly at a wavelength in the range of 230 nm to 500 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. In addition, since the light emitted from the ultraviolet LED, the purple LED, and the blue LED is efficiently emitted, it is suitable for a white LED or a colored LED using these LEDs as an excitation source. Especially, since it is excited efficiently at a wavelength around 405 nm, a white LED can be made by combining a purple LED and the present phosphor.

  A phosphor containing Ce as the metal element M, in particular, a phosphor containing Ca as the A element and Ce as the M element has a blue peak in a wavelength range of 450 nm to 550 nm when irradiated with an excitation source. Emits blue-green or green fluorescence. The excitation source is efficiently excited by ultraviolet rays, visible rays, electron beams, X-rays, and the like. In the case of excitation with ultraviolet light or visible light, excitation is particularly efficient with light having a wavelength in the range of 250 nm to 420 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 (405 nm), it is suitable for use as a white LED or a colored LED using these LEDs as an excitation source.

When trivalent ions are added, monovalent metal ions can be added simultaneously to compensate for the charge. Since Ce ³⁺ is considered to be replaced with ^{Ca 2+} of CaAl ₂ Si ₅ O ₂ N ₈ crystal, ^{Ce 3+} and by adding the same amount of Li ⁺ at the same time the crystal structure is stabilized electrical neutrality kept in To do.

The composition of the phosphor of the present invention is not particularly defined, but the composition formula M _a A _b Al _c Si _{d Le} O _f N _g (where L is a metal element other than M, A, Al, Si, in the formula, a + b + c + d + e + f + g = 1), and the parameters a, b, c, d, e, f, and g are preferably selected from values that satisfy all of the following conditions because the emission intensity is high.
0.00001 ≦ a ≦ 0.05
0.045 ≦ b ≦ 0.065
0.09 ≦ c ≦ 0.13
0.25 ≦ d ≦ 0.30
0 ≦ e ≦ 0.20
0.09 ≦ f ≦ 0.13
0.35 ≦ g ≦ 0.55

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 0.045 or more and 0.065 or less. If the b value is out of this range, the bond in the crystal becomes unstable, and the generation rate of a crystal phase other than the AAl ₂ Si ₅ O ₂ N ₈ crystal or the solid solution crystal increases, and the light emission intensity may decrease. Examples of the A element include Mg, Ca, Sr, Ba, and Zn. c is the amount of Al element, and it is preferable that the atomic ratio be 0.09 or more and 0.13 or less. If the c value is out of this range, the rate of generation of crystal phases other than AAl ₂ Si ₅ O ₂ N ₈ crystals or solid solution crystals increases, and the light emission intensity may decrease. d is the amount of Si element, and the atomic ratio is preferably 0.25 or more and 0.30 or less. If the d value is out of this range, the rate of generation of crystal phases other than AlON crystals or AlON solid solution crystals increases, and the light emission intensity may decrease. The e value is the amount of the metal element L (where L is one or more metal elements other than M, A, Al, and Si) and does not need to include the metal element L. 0.2 or less is good. If the e value exceeds 0.2, the crystal structure may become unstable, and the light emission intensity may decrease. f is the amount of oxygen, and is preferably 0.09 or more and 0.13 or less. If the f value is out of this range, the generation ratio of crystal phases other than AAl ₂ Si ₅ O ₂ N ₈ crystals or solid solution crystals increases, and the light emission intensity may decrease. g is the amount of nitrogen, and is preferably 0.35 or more and 0.55 or less. If the g value is out of this range, the generation ratio of crystal phases other than AAl ₂ Si ₅ O ₂ N ₈ crystals or solid solution crystals increases, and the light emission intensity may decrease. _Furthermore, within a range that does not disturb the crystalline structure of AAl ₂ Si ₅ O _{2 N 8} crystal or solid solution crystal may include such as fluorine or chlorine as the non-metal ions.

Among the compositions of the present invention, it is represented by a composition formula _{M x A 1-x Al 2} -y Si 5 + y O 2-y N 8 + y, parameter x, y is, the following equation 0.00018 ≦ x ≦ 0.5
-2 ≦ y ≦ 1.5
Since the shape of the emission spectrum and the excitation spectrum changes depending on the values of x and y, the x and y parameters may be selected depending on the application. In this formula, the composition changes so as to keep the sum of Si and Al and the sum of O and N in the crystal constant. In a region satisfying this relationship, it is easy to form a solid solution, and a stable solid solution crystal can be synthesized.

  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 a 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 rays or visible light having a wavelength of 100 nm or more and 480 nm or less, 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.

  As described above, by irradiating the phosphor of the present invention with an excitation source, fluorescence having a peak at a wavelength in the range of 450 nm to 700 nm is emitted, and the emitted color varies depending on the additive element.

In the present invention, from the viewpoint of fluorescence emission, it is desirable that the constituent AAl ₂ Si ₅ O ₂ N ₈ crystal or solid solution crystal is contained in a high purity and as much as possible, and preferably composed of a single phase. It can also be composed of a mixture with other crystalline phase or amorphous phase as long as the characteristics do not deteriorate. In this case, the content of AAl ₂ Si ₅ O ₂ N ₈ 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 is such that the content of AAl ₂ Si ₅ O ₂ N ₈ crystal or solid solution crystal is at least 10% by mass or more. The content ratio can be determined by performing X-ray diffraction measurement and conducting Rietveld analysis on AAl ₂ Si ₅ O ₂ N ₈ crystals or solid solution crystals and other crystal phases. In a simple manner, it can be determined from the ratio of the strengths of the strongest peaks of the AAl ₂ Si ₅ O ₂ N ₈ crystal or solid solution crystal and the other crystal phases.

  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. In addition, when selecting the same electroconductive substance as A element, it is necessary to pay attention to the variation of the composition.

The phosphor of the present invention develops blue, blue-green, green, yellow, orange, or red depending on the composition, but if it is necessary to mix with other colors, these colors are developed as necessary. Inorganic phosphors can be mixed. Other inorganic phosphors that can be used include oxides, sulfides, oxysulfides, oxynitrides, and nitride crystals as hosts, but the durability of the mixed phosphor 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 a different excitation spectrum and fluorescence spectrum depending on the composition, and can be set to have various emission spectra by appropriately selecting and combining them. 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.

The raw material mixture is filled in a container in a state in which the relative bulk density is maintained at a filling rate of 40% or less, and then fired in a temperature range of 1200 ° C. to 2200 ° C. in a nitrogen atmosphere of 0.1 MPa to 100 MPa. Here, the raw material mixture includes M metal, oxide, carbonate, nitride, fluoride, chloride, oxynitride, a compound containing M, or a combination thereof, and A metal, oxide, carbonate. Salts, nitrides, fluorides, chlorides, oxynitrides, compounds containing A, or combinations thereof and Al metals, oxides, carbonates, nitrides, fluorides, chlorides, oxynitrides, A compound containing Al, or a combination thereof and at least a metal, oxide, carbonate, nitride, fluoride, chloride, oxynitride, compound containing Si, or a combination of Si, or a combination thereof. Thereby, the phosphor of the present invention in which at least M is dissolved in the AAl ₂ Si ₅ O ₂ N ₈ 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, firing is preferably performed in a temperature range of 1600 ° C. or higher and 2000 ° C. or lower. In this way, a high-luminance phosphor can be obtained. When the firing temperature is lower than 1600 ° C., the production rate of AAl ₂ Si ₅ O ₂ N ₈ crystals or solid solution crystals may be low. Further, when the firing temperature is 2200 ° C. or higher, a special apparatus is required, which is not industrially preferable.

  As a starting material for the metal element M, a metal, an oxide, a carbonate, a nitride, a fluoride, a chloride, an oxynitride, a compound containing M, or a combination thereof can be used. It is preferable to use manganese carbonate or manganese oxide when M is Mn, cerium oxide when Ce is used, and europium oxide when Eu is used.

  As a starting material for the element A, a metal, an oxide, a carbonate, a nitride, a fluoride, a chloride, an oxynitride, a compound containing A, or a combination thereof can be used. When A is Ca, it is preferable to use calcium carbonate or calcium oxide.

  As a starting material of the silicon source, a metal, an oxide, a carbonate, a nitride, a fluoride, a chloride, an oxynitride, a compound containing silicon, or a combination thereof can be used. As the compound containing silicon, an organic precursor containing silicon, silicon diimide, an amorphous material obtained by heat treatment of silicon diimide, and the like can be used, but generally 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.

As a starting material for the aluminum source, metallic aluminum, aluminum oxide, aluminum nitride, a compound containing aluminum, or a combination thereof can be used. The compound containing aluminum is, for example, an organic precursor containing aluminum. As a starting material for the aluminum source, a mixture of aluminum nitride and aluminum oxide is 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. The amounts of aluminum nitride and aluminum oxide may be designed based on the target oxygen / nitrogen ratio of AAl ₂ Si ₅ O ₂ N ₈ .

  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. 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. When the constituent element of the inorganic compound is the same as the constituent element of the phosphor, it is necessary to pay attention to the variation of the composition.

  The nitrogen atmosphere is preferably a gas atmosphere in a pressure range of 0.1 MPa to 100 MPa. More preferably, it is 0.5 MPa or more and 10 MPa or less. When silicon nitride is used as a raw material, heating to a temperature of 1820 ° C. or higher in a nitrogen gas atmosphere lower than 0.1 MPa is not preferable because the raw material is likely to be thermally decomposed. When the pressure is higher than 0.5 MPa, the raw material is not thermally decomposed, which is preferable. 10 MPa is sufficient, and if it exceeds 100 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 has 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 fine powder”). 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% or less. More preferably, the bulk density is 20% 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. In this case, the firing 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. Are filled at a filling rate of 40% or less in bulk density. If necessary, the powder aggregate can be granulated to an average particle size of 500 μm or less using a sieve or air classification, and the particle size can be controlled. Moreover, you may granulate directly in the shape of 500 micrometers or less using a spray dryer etc. Further, when the container is made of boron nitride, there is an advantage that there is little reaction with the phosphor.

  The reason for firing with the bulk density kept at 40% 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% 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%, partial densification occurs during firing, resulting in a dense sintered body, which hinders crystal growth and may reduce the luminance of the phosphor. Moreover, it is difficult to obtain a fine powder. Further, the size of the powder aggregate is particularly preferably 500 μm or less because of excellent grindability after firing.

  Next, a powder aggregate having a filling rate of 40% 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 20 nm or less, 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 whose particle size has been adjusted by pulverization or classification can be heat-treated at a temperature of 1000 ° C. or higher and lower than the firing temperature. At a temperature lower than 1000 ° C., the effect of removing surface defects is small. Above the firing temperature, the pulverized powders are fixed again, which is not preferable. 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 a material different from normal oxide phosphors and existing sialon phosphors, and has a high level that exceeds or is comparable to these oxynitride phosphors or sialon phosphors. It is characterized by having visible light emission with luminance, and is suitable for lighting equipment 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-emitting light source and the fluorescent substance of this invention at least. Examples of lighting fixtures include LED lighting fixtures and fluorescent lamps. The LED lighting apparatus is manufactured by using the phosphor of the present invention 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 element of 330 to 420 nm, a green phosphor excited at this wavelength and having an emission peak at a wavelength of 520 to 550 nm, and a book having an emission peak at a wavelength of 590 to 700 nm There are combinations of the red phosphor of the invention and the blue phosphor of the invention. Examples of such a green phosphor include β-sialon: Eu ²⁺ described in JP-A-2005-255895. 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.

As another method, a blue LED or LD light emitting element of 430 nm to 470 nm, a green phosphor excited at this wavelength and having an emission peak at a wavelength of 520 to 550 nm, and a wavelength of 550 to 600 nm excited at this wavelength. There is a combination of a yellow phosphor having a light emission peak at the same time, a red phosphor of the present invention having an emission peak at a wavelength of 620 nm to 700 nm when excited at this wavelength, and an orange phosphor of the present invention. As such a green phosphor, β-sialon: Eu ²⁺ described in JP-A-2005-255895 is used. As such a yellow phosphor, α-sialon: Eu ²⁺ described in JP-A-2002-363554 is used. (Y, Gd) ₂ (Al, Ga) ₅ O ₁₂ : Ce described in JP-A-9-218149 and CaSiAlN described in WO 2005/052087 pamphlet as such a red phosphor. ₃ : Eu can be mentioned. In this configuration, when blue light emitted from the LED or LD is irradiated onto the phosphor, light of four colors of green, yellow, orange, and red is emitted, and mixed with the blue light emitted by the LED, Become.

  As another example, there is a combination of a 450 nm blue LED or LD light emitting element and the orange phosphor of the present invention having an emission peak at a wavelength of 580 nm or more and 620 nm or less excited at this wavelength. In this configuration, when blue light emitted from the LED or LD is irradiated on the phosphor, orange light is emitted, and the blue and orange colors of the LED are mixed, and the color temperature is white (bulb color or warm white). It becomes a lighting fixture.

  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.

The raw material powder is 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, an oxygen content of 0.93% by weight, and α-type 92% silicon nitride powder, specific surface area 13.6m ² / g, 99.99% pure aluminum oxide powder (Taimicron grade manufactured by Daimei Chemical), 99.99% pure calcium carbonate powder (high purity chemical reagent) Grade), 99.99% purity strontium carbonate powder (high purity chemical reagent grade), 99.99% purity barium carbonate powder (high purity chemical reagent grade), 99.9% purity europium oxide powder (Shin-Etsu) Chemical) and a cerium oxide powder (manufactured by Shin-Etsu Chemical) with a purity of 99.9% were used.

First, in order to synthesize a CaAl ₂ Si ₅ O ₂ N ₈ of theoretical _{composition, CaCO 3, Al 2 O 3} , AlN and _Si 3 _{N 4} powder CaCO in a molar ratio of _{3: Al 2 O 3: AlN} : Si 3 N ₄ was weighed so as to have a composition of 3: 1: 4: 5, mixed using a silicon nitride mortar and pestle, and then charged into a boron nitride crucible having a diameter of 20 mm and a height of 20 mm, It 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, and nitrogen having a purity of 99.9995 vol% is introduced at 800 ° C. to a gas pressure of 1 MPa. The temperature was raised to 1800 ° C. at 500 ° C. per hour and held at 1800 ° 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 and Table 1, almost single-phase CaAl ₂ Si ₅ O ₂ N ₈ was confirmed to be generated.

  From the results of X-ray diffraction measurement, this crystal could be indexed with hexagonal crystals. The lattice constant indexed with hexagonal crystals was a = 0.79045 nm and c = 0.57381 nm. From the result of X-ray diffraction, it was found that the present crystal has any one of the space groups of P31c, P-31C, P63mc, P-62c, and P63 / mmc. The determination of the space group requires the results of electron diffraction and convergent electron diffraction using a transmission electron microscope, but it has not been determined yet. In addition, this substance could be indexed even with orthorhombic crystals within the range of measurement error. In that case, the lattice constants were a = 0.574427 nm, b = 0.68481 nm, and c = 0.39540 nm.

Next, in order to synthesize a CaAl ₂ Si ₅ O ₂ N ₈ was activated by _{Eu, CaCO 3, Al 2 O} 3, AlN, Si 3 N 4 and _Eu 2 _{O 3} powder CaCO in a molar ratio of _3: Al ₂ O ₃ : AlN: Si ₃ N ₄ : Eu ₂ O ₃ was weighed so as to have a composition of 2.97: 1: 4: 5: 0.015, and mixed using a mortar and pestle made of silicon nitride. Later, it was put into a boron nitride crucible having a diameter of 20 mm and a height of 20 mm, and 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, and nitrogen having a purity of 99.9995 vol% is introduced at 800 ° C. to a gas pressure of 1 MPa. The temperature was raised to 1800 ° C. at 500 ° C. per hour and held at 1800 ° 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. 2 and Table 2, it was confirmed that CaAl ₂ Si ₅ O ₂ N ₈ containing almost single-phase Eu was generated.

  From the results of X-ray diffraction measurement, this crystal could be indexed with hexagonal crystals. The lattice constant indexed with hexagonal crystals was a = 0.78938 nm and c = 0.573338 nm. From the result of X-ray diffraction, it was found that the present crystal has any one of the space groups of P31c, P-31C, P63mc, P-62c, and P63 / mmc. The determination of the space group requires the results of electron diffraction and convergent electron diffraction using a transmission electron microscope, but it has not been determined yet.

<Examples 1-7>

Next, a phosphor containing the metal element Eu was synthesized. Table 3 summarizes the design compositions of Examples 1-7. To obtain the design formula shown in Table _{3 M a A b Al c Si} d L e O f N g compound represented by (a + b + c + d + e + f + g = 1), were weighed raw material powders in a mass ratio shown in Table 4, silicon nitride sintered After mixing using a mortar and pestle made of a knot, a powder aggregate having excellent fluidity was obtained by passing through a sieve having an opening of 125 μm. 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, and nitrogen having a purity of 99.9995 vol% is introduced at 800 ° C. to a gas pressure of 1 MPa. The temperature was raised to 1700 ° C. at 500 ° C. per hour and held at that temperature for 4 hours. The synthesized sample was ground with a mortar and pestle made of silicon nitride, it was conducted a powder X-ray diffraction measurement using a K _alpha line of Cu (XRD). In all compositions, formation of CaAl ₂ Si ₅ O ₂ N ₈ crystals or solid solutions was confirmed. From the ratio of the height of the main peak, the production ratio of CaAl ₂ Si ₅ O ₂ N ₈ crystals or solid solution crystals was determined to be 90% or more.

  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 light in orange. The emission spectrum and excitation spectrum of this powder were measured using a fluorescence spectrophotometer. Table 5 summarizes the excitation peak wavelength, emission peak wavelength, and fluorescence emission intensity results in the photoluminescence measurement. As shown in Table 5, these powders have an excitation spectrum peak at a wavelength in the range of 250 to 470 nm, and have an emission spectrum peak at a wavelength in the range of 550 to 700 nm upon excitation at the peak wavelength of the excitation spectrum. It was found to be a phosphor that emits 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. Excitation emission spectra of Example 3 and Example 6 are shown in FIGS. 3 and 4, respectively. In the figure, the peak that exceeds the display range of the vertical axis represents the direct light or doubled light of the excitation light, and is not the original spectrum, and can be ignored.

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 orange light.
<Comparative Example 8 and Examples 9 to 41>

Next, a phosphor containing the metal element Ce was synthesized. Table 6 summarizes the design compositions of Comparative Example 8 and Examples 9-41. To obtain a compound represented by Table 6 the design formula shown _{M a A b Al c Si d} L e O f N g (a + b + c + d + e + f + g = 1), were weighed raw material powders in a mass ratio shown in Table 7, silicon nitride sintered After mixing using a mortar and pestle made of a knot, a powder aggregate having excellent fluidity was obtained by passing through a sieve having an opening of 125 μm. 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, and nitrogen having a purity of 99.9995 vol% is introduced at 800 ° C. to a gas pressure of 1 MPa. The temperature was raised to 1700 ° C. or 1900 ° C. at 500 ° C. per hour and held at that temperature for 4 hours. The synthesized sample was ground with a mortar and pestle made of silicon nitride, it was conducted a powder X-ray diffraction measurement using a K _alpha line of Cu (XRD). In all compositions, formation of CaAl ₂ Si ₅ O ₂ N ₈ crystals or solid solutions was confirmed. From the ratio of the height of the main peak, the production ratio of CaAl ₂ Si ₅ O ₂ N ₈ crystals or solid solution crystals was determined to be 90% or more.

  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. Table 8 summarizes the excitation peak wavelength, emission peak wavelength, and fluorescence emission intensity results in the photoluminescence measurement. These powders are phosphors having an excitation spectrum peak at a wavelength in the range of 250 to 420 nm, and emitting light having an emission spectrum peak at a wavelength in the range of 450 to 550 nm upon excitation at the peak wavelength of the excitation spectrum. I understood that. 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. Excitation emission spectra of Example 12, Example 25, and Example 29 are shown in FIGS. 5, 6, and 7, respectively. In the figure, the peak that exceeds the display range of the vertical axis represents the direct light or doubled light of the excitation light, and is not the original spectrum, and can be ignored.

<Examples 42 to 67>

Next, phosphors with various compositions were synthesized. To obtain a compound represented by the design formula shown in Tables 9 and _{12 M a A b Al c Si} d L e O f N g (a + b + c + d + e + f + g = 1), the raw material powder at a mass ratio shown in Table 10 and Table 13 After weighing and mixing using a mortar and pestle made of sintered silicon nitride, a powder aggregate having excellent fluidity was obtained by passing through a sieve having an opening of 125 μm. 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, and nitrogen having a purity of 99.9995 vol% is introduced at 800 ° C. to a gas pressure of 1 MPa. The temperature was raised to 1800 ° C. at 500 ° C. per hour and held at 1800 ° C. for 4 hours. The synthesized sample was ground with a mortar and pestle made of silicon nitride, it was conducted a powder X-ray diffraction measurement using a K _alpha line of Cu (XRD). In all compositions, formation of CaAl ₂ Si ₅ O ₂ N ₈ crystals or solid solutions was confirmed. From the ratio of the height of the main peak, the production ratio of CaAl ₂ Si ₅ O ₂ N ₈ crystals or solid solution crystals was determined to be 90% or more.

  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 light. The emission spectrum and excitation spectrum of this powder were measured using a fluorescence spectrophotometer. Tables 11 and 14 summarize the excitation peak wavelength, emission peak wavelength, and fluorescence emission intensity results in the photoluminescence measurement. These powders are phosphors that have an excitation spectrum peak at a wavelength in the range of 250 to 480 nm, and emit light having an emission spectrum peak at a wavelength in the range of 450 to 700 nm upon excitation at the peak wavelength of the excitation spectrum. I understood that. 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. Excitation emission spectra of samples obtained by firing Example 58 and Example 66 at 1900 ° C. are shown in FIGS. 8 and 9, respectively. In the figure, the peak that exceeds the display range of the vertical axis represents the direct light or doubled light of the excitation light, and is not the original spectrum, and can be ignored.

The lighting fixture using the phosphor of the present invention will be described. In FIG. 10, 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 blue LED chip 2 having a wavelength of 450 nm are used as a light emitting element. The mixture phosphor 1 in which the orange phosphor of Example 3 of the present invention, the green phosphor of β-sialon: Eu, and the red phosphor of CaAlSiN ₃ : Eu are dispersed in the resin layer is placed on the LED chip 2. The structure is arranged in the 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 450 nm, and this light is a mixture of a green phosphor, an orange phosphor and a red phosphor. The phosphor 1 is excited to emit green, orange, 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.

Next, another type of lighting fixture in the white LED of FIG. 10 will be described. 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. A mixture phosphor 1 in which a blue-green phosphor of Example 12 of the present invention, a yellow phosphor of α-sialon: Eu, and a red phosphor of CaAlSiN ₃ : Eu are dispersed in a resin layer is provided on the LED chip 2. The structure is covered and placed in the 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, and 405 nm light is emitted. The blue-green phosphor, yellow phosphor, and red phosphor are emitted by this light. The mixture phosphor 1 is excited to emit blue-green, yellow and red light, respectively, and these lights are mixed to function as an illuminating device that emits white light.

A design example of an image display device using the nitride phosphor of the present invention will be described. FIG. 11 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 29 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.

  FIG. 12 is a schematic diagram of the principle of a field emission display panel as an image display device. The green phosphor of Example 29 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. Actually, however, a display that can produce various colors is constructed 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 comprises a host crystal different from conventional sialon phosphors and oxynitride phosphors, and emits light having an emission intensity exceeding or comparable to that of the host crystal, and further when exposed to an excitation source. Since there is little decrease in the luminance of the phosphor, it is a nitride phosphor 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 CaAl ₂ Si ₅ O ₂ N ₈ . X-ray diffraction chart of CaAl ₂ Si ₅ O ₂ N ₈ was activated by eu. 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 6. The excitation spectrum and emission spectrum by the fluorescence measurement of Example 12. The excitation spectrum and emission spectrum by the fluorescence measurement of Example 25. The excitation spectrum and emission spectrum by the fluorescence measurement of Example 29. The excitation spectrum and emission spectrum by the fluorescence measurement of Example 58. The excitation spectrum and emission spectrum by the fluorescence measurement of Example 66. 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

1 A mixture of an orange phosphor of the present invention (Example 3) and a green phosphor and a red phosphor, or a mixture of a blue-green phosphor of the present invention (Example 12), a yellow phosphor and a 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 Ultraviolet 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 (15)

AAl ₂ Si ₅ O ₂ N ₈ crystal (where A element is at least one element selected from the group consisting of Mg, Ca, Sr, Ba and Zn), or AAl ₂ Si ₅ O ₂ N _In the solid solution crystal of ₈ , M element (where M is at least one selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb) A phosphor containing at least an element. The phosphor according to claim 1, wherein the AAl ₂ Si ₅ O ₂ N ₈ is CaAl ₂ Si ₅ O ₂ N ₈ .   2. The phosphor according to claim 1, wherein Ca is contained as the A element, Eu is contained as the M element, and fluorescence having a peak in a wavelength range of 550 nm to 700 nm is irradiated by irradiating an excitation source. A phosphor that emits light.   2. The phosphor according to claim 1, wherein Ca is contained as the A element, Ce is contained as the M element, and fluorescence having a peak in a wavelength range of 450 nm to 550 nm is irradiated by irradiating an excitation source. A phosphor that emits light.   The phosphor according to claim 4, further comprising Li.   2. The phosphor according to claim 1, wherein Zn is contained as the A element, Eu is contained as the M element, and irradiation with an excitation source causes fluorescence having a peak in a wavelength range of 500 nm to 600 nm. A phosphor that emits light.   2. The phosphor according to claim 1, which emits fluorescence having a peak in a wavelength range of 450 nm to 550 nm by irradiating an excitation source containing Sr as the A element and Eu as the M element. A phosphor characterized in that:   2. The phosphor according to claim 1, wherein Ba is contained as the A element, Eu is contained as the M element, and irradiation with an excitation source causes fluorescence having a peak in a wavelength range of 450 nm to 550 nm. A phosphor that emits light. 2. The phosphor according to claim 1, wherein the composition formula M _{a Ab} Al _cS i _{d Le} O _f N _g (where L is a metal element other than M, A, Al, and Si, wherein a + b + c + d + e + f + g = 1), and parameters a, b, c, d, e, f and g are
0.00001 ≦ a ≦ 0.05
0.045 ≦ b ≦ 0.065
0.09 ≦ c ≦ 0.13
0.25 ≦ d ≦ 0.30
0 ≦ e ≦ 0.20
0.09 ≦ f ≦ 0.13
0.35 ≦ g ≦ 0.55
A phosphor characterized by satisfying the above conditions. The phosphor according to claim 1, wherein the phosphor is represented by a composition formula M _x A _1-x Al _{2 -y} Si _{5 + y} O _{2 -y} N _{8 + y} , and parameters x and y are:
0.00018 ≦ x ≦ 0.5
-2 ≦ y ≦ 1.5
A phosphor characterized by satisfying the following condition.   M metals, oxides, carbonates, nitrides, fluorides, chlorides, oxynitrides, compounds containing M, or combinations thereof, and metals, oxides, carbonates, nitrides, fluorides of A , Chlorides, oxynitrides, compounds containing A, or combinations thereof, and Al metals, oxides, carbonates, nitrides, fluorides, chlorides, oxynitrides, compounds containing Al, or A raw material mixture containing at least a combination thereof and a metal, oxide, carbonate, nitride, fluoride, chloride, oxynitride, compound containing Si, or a combination of Si, or a relative bulk density of 40 2. The method according to claim 1, wherein the container is filled in a state of being held at a filling rate of not more than% and then fired in a temperature range of 1200 ° C. to 2200 ° C. in a nitrogen atmosphere of 0.1 MPa to 100 MPa. How to make phosphor .   A lighting apparatus including a light emitting source that emits light having a wavelength of 330 to 470 nm and a phosphor, wherein the phosphor includes the phosphor according to claim 1. The lighting fixture according to claim 12,
The light emitting source includes an LED or an LD,
The lighting apparatus according to claim 1, wherein the phosphor further includes a green phosphor having an emission peak at a wavelength of 520 nm to 570 nm.   An image display device including an excitation source and a phosphor, wherein the phosphor includes the phosphor according to claim 1.   15. The image display device according to claim 14, 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 An image display device characterized by being an electron beam having an acceleration voltage of 10 V or more and 30 kV or less.