JP2000026854A - Liminous oxide having stuffed tridymite type or kaliphilite type structure and oxide luminophor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a luminous oxide which shows excellent heat resistance and chemical stability, is useful for a luminophor of a high luminance capable of emitting light of colors from blue to yellow and shows afterglow by using a compound oxide having a specific composition. SOLUTION: An oxide to be used has a stuffed tridymite type structure having a composition of M1M22O4 or a kaliphilite type structure having a composition of M1M32O4 (wherein M1 is an alkaline earth metal element selected from Ca, Sr and Ba; M2 is a metal element selected from Al and Ga; and M3 is Si, Mg or Zn). Further, the alkaline earth metal element M1 of the oxide is substituted by a divalent ion of europium or a trivalent ion of other rare earth metal element provided that the substitution ratio is not more than 30 mol.% of the sum of the alkaline earth metal element ions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a light-emitting device which emits light after being excited by visible / ultraviolet light or an electron beam, so that it can be used as a display or illumination in dark places such as indoors and outdoors, and underwater. More specifically, the present invention relates to a crystalline oxide and a high-brightness light-emitting material having a high color purity and comprising a stuffed tridymite-type structure (monoclinic system) or a caricasmite-type structure (hexagonal system) having the same form. The present invention relates to an inorganic oxide having the same, a luminous body thereof, a luminous body containing a rare earth element ion or a transition metal ion known to be a luminescent center, and a method for producing them.

[0002]

2. Description of the Related Art Blue, green,
Since each red light emitter needs to have high luminance, various sulfides, for example, specifically, light emitters such as zinc sulfide and yttrium oxysulfide have been conventionally used. However, it has been pointed out that these sulfides have a problem of deterioration such as generation of an afterimage (burn) due to long-term use or chemical decomposition of the filament portion of the electron gun due to thermal decomposition. I have. In particular, in high-definition televisions and other applications where the main purpose is to display information on a computer, the necessity of increasing the number of scanning lines reduces the application area of the luminous body, and the electron beam is strong enough to maintain the same brightness. Irradiation is required. Further, as a luminous body for plasma display as a flat display, development of the same kind of luminous body having excellent thermal and chemical stability is indispensable.

[0003] Under such circumstances, luminous bodies made of oxides have been attracting attention as a solution to the problems of low heat resistance and chemical instability, which are disadvantages of luminous bodies such as sulfides. However, in practice, phosphates, borates,
Some oxides of silicates and aluminates have excellent thermal and chemical stability,
Although known as a luminous body that emits light, the number of those that efficiently excite and emit light with an accelerated particle beam such as an electron beam is small.

For example, recently, as an oxide phosphor that emits bright light by ultraviolet rays or the like, a phosphor obtained by adding Eu ²⁺ as a main activator to an oxide having a stuffed tridymite type structure belonging to a monoclinic system has been reported (J. . Electrochem. Soc., 118, 930
(1971), U.S. Pat. No. 2,392,814, U.S. Pat.
Japanese Patent Application Laid-Open No. 7-11250 discloses that this compound exhibits long afterglow light storage characteristics in combination with other rare earth ions. At high temperatures, these compounds undergo a phase transition to a highly symmetric hexagonal system. A phase belonging to a hexagonal system and having a large superlattice unit cell has also been found (Z. anorg. Allg. Chem., 415, 40 (1979)). However, an oxide having a stuffed tridymite structure having more excellent light emitting properties has not been provided yet.

[0005] On the other hand, there is a compound of the same skeleton, which is called a calycasite (KAlSiO ₄ ) type compound. It belongs to a hexagonal system, and has a skeleton structure of a six-membered ring in which tetrahedrons having a stuffed tridymite structure are alternately replaced by upward AlO ₄ tetragons and downward SiO ₄ tetrahedra. In addition, various reports on compounds with similar structures (Bu
ll. Soc. Fr. Mineral. Crystallogr., 87, 108 (1964),
J. Inorg. Nucl. Chem., 38, 983 (1976), Z. Anorg.
Allg. Chem., 475, 205 (1981), Mineral. Mag., 45, 111.
(1982), Bull.Mineral., 108, 643 (1985), Z. Kristal
logr., 176, 29 (1986), J. Solid State Chem., 71, 36
1 (1987), Phys. Chem. Minerals., 16, 276 (1988), Eu
r. J. Mineral., 2, 273 (1990)), however, no report has been made on the luminescent properties of these compounds.

[0006]

SUMMARY OF THE INVENTION In view of the circumstances as described above, the invention of the present application aims at solving the problems of low heat resistance and chemical instability, which are disadvantages of luminous bodies such as sulfides, and has been proposed as a method for solving the problem. It is an object of the present invention to provide a new oxide luminous body having a stone type or stuffed tridymite type structure. Further, the present application activates a rare earth metal ion or a transition metal ion serving as an emission center,
Another object of the present invention is to provide a luminous body having a new afterglow property due to a non-stoichiometric composition, in addition to a high-luminance luminous body that emits blue to yellow light.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present application first discloses a first invention of M
¹ M ² ₂ O ₄ (wherein M ¹ represents one or more alkaline earth metal elements selected from Ca, Sr and Ba,
² represents one or more elements selected from Al and Ga) and provides a luminescent oxide having a stuffed tridymite structure.

[0008] This application discloses a second invention, M
^{_{1 M 3 2 O 4 (M}} 1 in the formula, Ca, one or more alkaline earth metal elements selected from Sr and Ba, M
³ represents a metal element of Si and Mg or Zn), and provides a light-emitting oxide characterized by having a calycasite-type structure. This application relates to the oxide of the first or second invention,
As a third invention, an oxide characterized in that a part of the alkaline earth metal element ion of M ¹ is substituted with europium divalent ion, and as a fourth invention, substitution with europium divalent ion is carried out. 10 or less mole% oxide, as a fifth aspect of the invention, the oxide of the first or second invention, a part of europium divalent ions and other rare earth metals third alkaline earth metal ions of M ¹ An oxide characterized in that it is substituted by a valent ion, as a sixth invention, an oxide whose substitution by a europium divalent ion and another rare earth trivalent ion is 10 mol% or less,
As a seventh invention, the oxide of the second invention has M ³
The oxide portion of the metal element ion is characterized in that it is substituted by Mn ^2+, as an invention of the 8, Mn ²⁺
Also provided is an oxide having up to 50 mol% of substitutions by:

[0009] Further, the present application provides, as a ninth invention,
A luminous body comprising the oxide according to any one of the first to eighth inventions is provided as a tenth invention, which is excited by an accelerated electron beam or excited by ultraviolet / visible light in a range of 140 to 480 nm. A luminous body which emits light based on the luminous body is provided. Further, the present application provides, as an eleventh invention, a method for producing an oxide according to any one of the first to eighth inventions, wherein a compound of a raw material element constituting the oxide composition is mixed,
As a twelfth invention, a method for producing an oxide characterized by firing after pressure molding, a production method for performing calcination before pressure molding, as a thirteenth invention, in a reducing atmosphere or air, A manufacturing method for firing at a temperature of 1150 to 1550 ° C is also provided. As described above, the invention of this application is:
The present invention has been completed as a result of detailed studies by the inventor of the present application as follows. That is, based on the knowledge of the prior art, the chemical composition formula is AB ₂ O ₄ (where A is mainly an alkaline earth metal ion and B is
Investigations have been made mainly on the compound group represented by (valent ion), and in addition to the compound having the spinel structure, the caricasite-type structure (staffed tridymite-type structure (monoclinic system) or a similar isomorph thereof ( Hexagonal compound was newly synthesized, and it was found that “self-activated light emission” was obtained by optimizing the composition and firing process of this composite oxide.

Using this as a base material, a luminous body can be produced in which a luminescent center ion such as Eu ²⁺ or Mn ²⁺ is activated, and when Eu ²⁺ is activated, various rare earth metal ions can be further produced. It has been found that co-activation results in an extremely high-luminance luminescent material. Moreover, certain oxide material or after pressurized molding the powder previously synthesized spinel structure at a pressure of 1kg / cm ³ ~5000kg / cm ³ by calcination, by re-firing of the object Stuffed tri di chromite structure It has been found that a sintered body having the following characteristics can be produced, and the object of the present invention can be achieved as a light emitting body.

[0011]

DETAILED DESCRIPTION OF THE INVENTION As described above, the invention of this application
Is that (1) the composition formula is M¹M^Two _TwoO_FourOr M¹M ^Three _TwoO
_Four(Where M¹Is selected from Ca, Sr and Ba
One or more alkaline earth metal elements, M^TwoIs Al,
And one or more elements selected from Ga and
M^ThreeIs one selected from Si and Mg and Zn
Element) represented by stuffed tridymite type or
Oxides having a calycasite-type structure, (2) M¹Al
Some potassium earth metal ions are converted to europium divalent ions.
And replace it with other rare earth metal trivalent ions.
(3) M^ThreeElement of Mn²⁺Put in
Oxides resulting from replacement, and oxides of (4) and above
And (5) pressure-forming of these oxides.
It is intended to provide a production method by firing.

M¹M^Two _TwoO_FourRepresented by the chemical composition formula
Composite oxide with toughdotridymite structure (monoclinic)
For (Ca_lSr_mBa_1-lm) (Al_nGa
_1-n)_TwoO_FourAnd each of l, m and n is represented by 0 to 1.
It can also be. For example, CaAl_TwoO_Four;
SrAl_TwoO_FourBaGa_TwoO_Four; Ca_0.5Sr _0.5A
l_TwoO_FourIe, CaSrAl_FourO₈Ba_0.5Sr
_0.5Ga_TwoO_FourIe, BaSrGa_FourO₈; SrA
lGaO_Four; BaAl_0.5Ga_1.5O_FourIe, Ba
_TwoAlGa_ThreeO₈Etc. are indicated as the composition. in
Also useful in the present invention as a luminescent oxide
In sex, M¹Is two or more, CaSrAl_FourO₈,
BaSrGa_FourO₈Etc. are exemplified as more appropriate ones.
You.

On the other hand, of the calycasite structure (hexagonal),
M¹M^Three _TwoO_FourThe composite oxide represented by the chemical composition formula of
(Ca_lSr_mBa_1-lm) [(Mg_pZn_1-p)_qS
i_1-q]_TwoO_FourWhere l, m, and q are 0 to 1, and p is 0 or
Can be represented by 1. For example, BaM
gSiO_FourBa_0.5Sr_0.5MgSiO_FourBa_0.1
Ca _0.9MgSiO_Four; BaZnSiO_Four; Ca_0.5B
a_0.5Zn_0.5Si_1.5O_FourAnd so on. Above all, this
Oxides of the calycite structure include (Ca, Sr and
And / or Ba) MgSiO_Four, (Ca, Sr and / or
Or Ba) ZnSiO_FourOf suitable composition
It is listed as.

In the present invention, the luminescent composite
As an oxide, M¹M^Two _TwoO _FourStaff Dotori
Oxide having a dimite type structure (monoclinic) and M¹M^Three _TwoO
_FourAny of the oxides of the caricasite-type structure (hexagonal)
In the case of¹Of alkaline earth metal ions
Divalent ion of ropium (Eu) or more
Other rare earth metal elements in combination with trivalent ions
A replacement is provided. The replacement in this case is M¹Al
The total amount of potassium earth metal ions is preferably 30
% Or less, more preferably about 1 to 15 mol%, and
% Is appropriate. More than 30 mol%
When it is possible to obtain, the above-mentioned specific structure as a composite oxide is
It is difficult to obtain and it is expected that the emission characteristics will improve
I can't. On the other hand, when the content is less than 1 mol%, the light emission characteristics are improved.
It becomes hard. From the viewpoint of emission characteristics, the above-mentioned M¹M^Three _TwoO_Four
Of the complex oxide having a carcassite type structure of^ThreeSource of
The elementary ion is a manganese ion (Mn²⁺) Is replaced by
Are also provided by the present invention. Replacement in this case
Is at most 70 mol%, further preferably at most 50 mol%, more preferably
Preferably, those substituted at a rate of 10 to 50 mol% are suitable.
Exemplified as appropriate.

The luminous body of the present invention is more characteristically one that emits light based on excitation by an accelerated electron beam or excitation by ultraviolet / visible light in the range of 140 to 480 nm. Is done. In the production of the composite oxide of the present invention, generally, the compounds of the raw material elements constituting the oxide composition are mixed in a dry or wet method, and the mixed powder is subjected to pressure molding (for example, pressure of 1 to 5000).
kg / cm ² ) and then firing.

Prior to the pressing, the powder may be calcined. The temperature in this case depends on the composition,
About 00 to 950 ° C. can be used as a guide. Also,
The firing is also different depending on the composition, but 1150 to 15
The reaction can be carried out under a reducing atmosphere or in the air, using a temperature of about 50 ° C. as a guide. The reducing atmosphere is suitably a mixed atmosphere of a rare gas such as argon or helium and a hydrogen gas.

By using the composite oxide of the present invention as described above, a high-luminance luminous body that emits blue to yellow light as a base substance of a characteristic luminous body, and a luminous body that exhibits afterglow can be obtained. Can be provided. Therefore, an embodiment will be described below and described in more detail.

[0018]

Example 1 CaCO ₃ , SrCO ₃ and Al ₂ O ₃
Were weighed and mixed so as to have a molar ratio of 1: 1: 2 (sample A). In addition, separately from this, the chemical formula [(CaSr)
_0.90 Eu _0.1 ] ₂ Al ₄ O ₈ CaCO ₃ , S
rCO ₃ , Al ₂ O ₃ and Eu ₂ O ₃ were weighed, and wet-mixed with a ball mill in ethanol for 24 hours.
The sample was dried (sample B). Each of the mixed samples A and B was uniaxially press-molded under the condition of 100 MPa.
In the range of 200 ° C to 1500 ° C, a reducing atmosphere (5
% H ₂ / Ar gas) for 24 hours. However, the heating rate was set to 5 ° C./min, and the furnace was gradually cooled after holding at a predetermined temperature for 24 hours.

In the heat treatment at 1300 ° C., (Ca, Sr)
A weak peak corresponding to ₃ Al ₂ O ₆ appeared,
It has been found that a single phase can be obtained by heat treatment at 0 ° C. to 1500 ° C. From the results of powder X-ray diffraction, it was confirmed that both samples A and B belong to a monoclinic system like SrAl ₂ O ₄ . Further, according to the sample A, the lattice constants are a = 8.268 (7) Å and b = 8.76.
(2) Å, c = 15.36 (2) Å, β = 92.2
(5) was obtained. FIG. 1 schematically shows a stuffed tridymite structure, which is a crystal structure of a newly obtained compound of sample A, CaSrAl ₄ O ₈ .

The upward and downward AlO ₄ coordination tetrahedra are alternately connected while sharing the vertices, forming a layered skeleton composed of six-membered rings. Further, since the obtained X-ray diffraction peak was slightly broad, an attempt was made to prepare a powder sample having high crystallinity using NaBF ₄ (5 wt%) as a flux. Since there are two types of substitution sites for alkaline earth metal ions in this crystal structure, each atomic parameter by Rietveld analysis is set by setting the occupancy of Ca and Sr to 0.5 and the temperature factor to 0.5. When optimization was performed, it was found that Ca and Sr occupy different sites.

Since this compound showed a behavior accompanied by an endothermic change at around 680 ° C., it is considered that there is a structural phase transition from a monoclinic system to a hexagonal system like SrAl ₂ O ₄ . On the other hand, for sample B, when the firing was repeated several times at 800 ° C., the crystal phase belonging to the orthorhombic system (a = 8.19)
6 (2) Å, b = 8.776 (3) Å, c = 15.18
0 (6)}). The lattice constant of this phase is c ≒ √
Since the relationship of 3b was recognized, it was considered that the hexagonal phase was distorted with the change in composition.

FIG. 2 shows that [(CaS
r)_0.90Eu_0.1]_TwoAl_FourO₈Excitation and emission spectra
Showed. From this FIG.²⁺Activated SrAl
_TwoO _FourIn this case, the emission has a peak near 520 nm.
But Eu²⁺Activated CaSrAl_FourO₈But almost
A filter having the same emission intensity and having a maximum intensity around 480 nm.
It turned out to be a peak load.

FIG. 3 shows the measurement results of the fluorescence lifetime.
Here, the JIS standard for phosphorescent pigments (JIS K5120)
Based on the phosphorescent luminance test method specified in, conventional light source D ₆₅
Is shown as a change in afterglow luminance over time after irradiation at 200 lux for 10 minutes. From FIG. 3, [(CaS
r) _0.90 Eu _0.1 ] ₂ Al ₄ O ₈ tends to exhibit a slightly longer afterglow. However, SrAl ₂ O
_{Since 4} was predicted to be almost the same afterglow mechanism,
The reason for the improvement is that Sr and Ca occupy different substitution sites, and then the sites where Eu ²⁺ can be substituted are restricted to either one, so that concentration quenching and the effect of the killer center can be avoided. Conceivable.

[0024]

Embodiment 2 BaCO ₃ , SrCO ₃ and Ga ₂ O ₃
Were weighed and mixed to give a molar ratio of 1: 1: 2. Further, the chemical formula [(BaSr) _0.9 Eu _0.1 ] ₂ Ga ₄ O ₈
Eu ₂ O ₃ was weighed and wet-mixed in ethanol for 24 hours by a ball mill. After drying in the air, this was uniaxially pressed under the conditions of 100 MPa,
In the range of 200 ° C. to 1400 ° C., a reducing atmosphere (5% H ₂ /
(Ar gas).

At 1200 ° C., an X-ray powder diffraction pattern was obtained in which an unknown phase having a low strength coexisted. However, it was found that a substantially single phase was obtained by treating at 1250 ° C. for 72 hours. This is attributed to a hexagonal system, which is a high-temperature phase of a stuffed tridymite structure, like BaAl ₂ O _4, and its lattice constant is a _hex = 5.282 (6) Å, c _hex =
8.789 (5)}. By the way,
BaSrGa ₄ O ₈ can be indexed to orthorhombic, and its lattice constant is a _ortho = 8.742 (5) Å, b
_ortho = 9.182 (6) Å, _ortho = 15.915
(7) Å, which is a _hex ≒ c _ortho / 3, a
The relationship of _hex × {3} b _ortho indicates that the hexagonal phase has a distorted crystal structure.

[(BaSr) _0.90 Eu _0.1 ] ₂ GaGa
_From the measurement of the excitation / emission spectrum of ₄ O ₈ , 530 nm
Broad peak assignable to 4f ⁶ 5d ¹ → 4f ⁷ transition Eu ²⁺ was observed in the vicinity.

[0027]

Example 3 BaCO ₃ , MgO and SiO ₂ were converted to a chemical composition BaMg _1-x SiO ₄ (x = ± 0.3, ± 0.1,
0), and the obtained powder sample was calcined at 900 ° C. for about 12 hours, then uniaxially pressed under the condition of 100 MPa, and pressed at 1200 ° C. to 1500 ° C. for 1 hour.
The reaction was performed in air for 2 hours.

From the results of the powder X-ray diffraction shown in FIG.
MgSiO_Four(Sample of x = 0) is 1500 ° C.
It can be seen that a single phase can be synthesized under the firing conditions. Also,
Under firing conditions of 1500 ° C. or less,
Ba as product_ThreeMgSi _TwoO₈(JCPDS Car
No. 10-74).
This compound is stoichiometric in a reaction at 1300 ° C for 12 hours.
Can be synthesized as a single phase from a mixture of composition ratio
You. Further, mixing and reaction were performed at the above non-stoichiometric composition ratio.
For the sample, Ba_ThreeMgSi_TwoO₈The existence of
It could be confirmed. Especially for samples with low Mg,
The presence of an unidentified phase was also confirmed.

[0029] The obtained CaMica-type structure BaMgS
iO ₄ can be indexed in a hexagonal system, and its lattice constant is
a = 9.122 (2)} and c = 8.743 (6)}. This means that in the crystal structure shown in FIG.
Instead of the lO ₄ coordination tetrahedron, the upward MgO ₄ coordination tetrahedron and the downward SiO ₄ coordination tetrahedron are connected to each other while sharing vertices, forming a layered skeleton composed of six-membered rings.

FIG. 5 shows the result of an emission spectrum based on the electron beam excitation of BaMgSiO ₄ . About 510
Strong green light emission (self-activation type) was shown in nm. This light emission is deeply related to a skeletal structure in which an upward MgO ₄ coordination tetrahedron and a downward SiO ₄ coordination tetrahedron are connected to each other by sharing vertices, and according to Rietvelt analysis, there are two in particular. It may be caused by a defect in only one of the Ba ²⁺ ion sites.

[0031]

Embodiment 4 BaCO ₃ , SrCO ₃ , MgO and S
iO ₂ was converted to a chemical composition Ba _1-x Sr _x MgSiO ₄ (x =
0.1, 0.5), and after calcining the obtained powder sample at 900 ° C. for about 12 hours,
Uniaxial pressure molding under the conditions of
The reaction was performed in air for 2 hours.

From the results of the powder X-ray diffraction shown in FIG. 6, the lattice constant of BaMgSiO ₄ (a =
9.122 (2)}, c = 8.743 (6)})
It can be seen that the symmetry is changed to low symmetry by replacing with Sr ²⁺ having an ionic radius of about 20% smaller than a ²⁺ . Since the diffraction peak was not sharp, an accurate lattice constant could not be obtained.
It can be seen that three peaks characteristic of a monoclinic phase appear at 2θ = 29 ° to 33 ° in a diffraction pattern using as a radiation source.

[0033]

Embodiment 5 BaCO ₃ , CaCO ₃ , MgO and S
The iO ₂ was converted to the chemical composition Ba _1-x Ca _x MgSiO ₄ (x =
0.1, 0.5), and after calcining the obtained powder sample at 900 ° C. for about 12 hours,
Uniaxial pressure molding under the conditions of
The reaction was performed in air for 2 hours.

The powder X-ray diffraction pattern shown in FIG. 7 shows that the lattice constant of BaMgSiO ₄ assigned in hexagonal system is Ba ²⁺
By partially replacing Ca ²⁺ with a smaller ionic radius by about 37%, the symmetry changes to a monoclinic system at x = 0.1 more remarkably than the case shown in Example 4. Was observed.

[0035]

Example 6 BaCO ₃ , ZnO and SiO ₂ were converted to a chemical composition BaZn _1-x SiO ₄ (x = ± 0.3, ± 0.1,
0), the powder sample was calcined at 900 ° C. for about 12 hours, and then uniaxially pressed under the condition of 100 MPa, and pressed at 1200 ° C. to 1300 ° C. for 1 hour.
The reaction was performed in air for 2 hours.

As shown in the powder X-ray diffraction pattern of FIG.
aZnSiO_FourIs crystalline at 1200 ° C to 1300 ° C
High, almost single phase was found. FIG.
BaMgSiO shown in Example 3_FourAlong with this example
BaZnSiO shown_FourEmission spectroscopy based on electron beam excitation
Torr results were shown. All are strong green at about 510nm
Light emission (self-activation type) was shown. This light emission is upward M
gO _FourCoordinating tetrahedron and downward SiO_FourCoordination tetrahedra
Deeply involved with the skeletal structure that shared the vertices
According to the Rietvelt analysis method, two types of Ba²⁺Io
May be caused by only one defect
It indicates that there is.

FIG. 10 shows the BaZnSiO of this embodiment.
₄ was prepared by adding _{Eu 2 O 3 Ba 0.95 Eu 0.05} Z
The measurement results of the fluorescence lifetime of nSiO ₄ are shown. This is a blue luminous body having a maximum intensity around 470 nm, and it can be seen from FIG. 10 that it has a long afterglow.

[0038]

Embodiment 7 BaCO ₃ , Eu ₂ O ₃ , MgO and S
iO ₂ was weighed to have a chemical composition of Ba _0.95 Eu _0.05 MgSiO _4, and the obtained powder sample was calcined at 900 ° C. for about 12 hours. The reaction was conducted for 24 hours in a temperature range of 1500 ° C. and a reducing atmosphere (5% H ₂ / Ar gas).
However, the rate of temperature rise was 5 ° C./min, and after the reaction for 24 hours, the sample was recovered by slow cooling in the furnace.

The obtained Ba _0.95 Eu _0.05 MgSiO
₄ can be indexed in hexagonal system from the result of powder X-ray diffraction, and its lattice constant is a = 9.115 (4) Å, c =
8.739 (7)}. It has the same calcareous stone structure as in Example 3. In FIG.
The emission spectrum of the obtained Ba _0.95 Eu _0.05 MgSiO ₄ was shown. From FIG. 11, SrAl ₂ activated with Eu ²⁺ is shown.
O ₄ emitted light having a peak near 520 nm, whereas Ba _0.95 Eu _0.05 MgSiO ₄ had a light emission of 360
It can be seen that the blue light emission having the maximum intensity near 470 nm with almost the same light emission intensity by the excitation of nm.

FIG. 12 shows the measurement results of the fluorescence lifetime. Results of the samples in BaZnSiO ₄ made was added Eu ₂ O ₃ in the concentration shown by Example 6. FIG.
Therefore, Ba _0.95 Eu _0.05 MgSiO ₄ is also Ba _0.95 Eu
It is evident that _0.05 ZnSiO ₄ also exhibits nearly the same long afterglow.

[0041]

Embodiment 8 BaCO ₃ , ZnO, MgO and SiO
₂ was weighed so as to have a chemical composition of BaZn _0.95 Mn _0.05 SiO _4, and the obtained powder sample was calcined at 900 ° C. for about 12 hours, and then uniaxially pressed under the condition of 100 MPa.
1200 ° C to 1500 ° C temperature range, reducing atmosphere (5%
(H ₂ / Ar gas) for 24 hours.

From the results of the powder X-ray diffraction, the obtained BaZ
n_0.95Mn_0.05SiO_FourIs the BaZn shown in Example 6.
SiO_FourThe index can be indexed in the hexagonal system as in
The constants are a = 9.105 (5) Å and c = 8.726.
(4) It turned out that it became Å. Zn²⁺Mn compared to²⁺
Considering that the ionic radius of B is about 8% larger,
aZnSiO_FourIs the lattice constant, a = 9.097 (5)
{, C = 8.714 (7)}, Z
n²⁺Part of the ion site of Mn²⁺May be replaced by
Can be considered. Also, from the measurement results of the excitation emission spectrum,
Mn²⁺of^FourT₁→ ⁶A₁Peak attributed to the transition
Was observed around 510 nm.

[0043]

As described in detail above, the invention of this application is excellent in heat resistance and chemical stability, and is useful as a high-luminance luminous body which emits blue to yellow light, and also has an afterglow property. A new composite oxide that can be shown is provided.

[Brief description of the drawings]

FIG. 1 is a schematic view of a stuffed tridymite crystal structure.

FIG. 2 SrAl ₂ O ₄ ; Eu ²⁺ and CaSrAl
FIG. _{4 is} an excitation / emission spectrum diagram of ₄ O ₈ ; Eu ²⁺ .

FIG. 3 CaSrAl ₄ O ₈ ; Eu ²⁺ and SrAl
FIG. 5 is a diagram showing a time change of the fluorescence intensity of ₂ O ₄ ; Eu ²⁺ .

FIG. 4 is a powder X-ray diffraction pattern depending on a difference in firing temperature of BaMgSiO ₄ .

FIG. 5 is a spectrum diagram of canard luminescence of BaMgSiO ₄ .

FIG. 6 shows a chemical composition Ba _1-x Sr _x MgSiO ₄ (x = 0.5) obtained by firing in air at 1500 ° C. for 12 hours.
(A), It is a powder X-ray diffraction diagram of 0.1 (b).

FIG. 7 shows a chemical composition Ba _1-x Ca _x MgSiO ₄ (x = 0.5) obtained by calcining in air at 1500 ° C. for 12 hours.
(A), It is a powder X-ray diffraction diagram of 0.1 (b).

FIG. 8 is a powder X-ray diffraction diagram depending on a difference in sintering temperature of BaZnSiO ₄ .

FIG. 9 is a cathodoluminescence spectrum diagram of BaMgSiO ₄ and BaZnSiO ₄ .

FIG. 10 is a diagram showing a time change of the emission intensity of Ba _0.95 Eu _0.05 ZnSiO ₄ .

FIG. 11: Ba _0.95 Eu _0.05 MgSiO ₄ and Sr _0.95 E
emission spectrum of u _0.05 AlO ₄ (excitation wavelength; λ = 36
0 nm).

FIG. 12: BaMgSiO ₄ ; Eu ²⁺ and BaZnSiO
₄ : Emission intensity with Eu ²⁺ (excitation wavelength; λ = 360 nm)
FIG. 5 is a diagram showing a time change of the sigma.

Claims (13)

[Claims] 1. The following formula: M ¹ M ² ₂ O ₄ (where M ¹ is at least one kind of alkaline earth metal element selected from Ca, Sr and Ba, and M ² is a group consisting of Al and Ga A light-emitting oxide having a stuffed tridymite structure. 2. The following formula: M ¹ M ³ ₂ O _{4 wherein} M ¹ is at least one kind of alkaline earth metal element selected from Ca, Sr and Ba, M ³ is Si,
A light-emitting oxide having a composition represented by the formula: 3. The oxide of claim 1 or 2, wherein M
^1. A luminescent oxide, characterized in that part of the alkaline earth metal element ion of ¹ is replaced by europium divalent ion. 4. The method according to claim 1, wherein the substitution with the europium divalent ion is 1
The luminescent oxide according to claim 3, which is 0 mol% or less. 5. The oxide of claim 1 or 2, wherein M
A luminescent oxide, characterized in that part of the alkaline earth metal element ion ( ¹⁾ is replaced by europium divalent ion and another rare earth metal trivalent ion. 6. The substitution by europium divalent ions with other rare earth trivalent ions is 10 mol% or less.
Luminescent oxide. 7. The light-emitting oxide according to claim 2, wherein a part of the metal element ion of M ³ is substituted by Mn ²⁺ . 8. The luminescent oxide according to claim 7, wherein the substitution with Mn ²⁺ is 50 mol% or less. 9. A luminous body comprising the oxide according to claim 1. 10. The luminous body according to claim 9, which emits light based on excitation by an accelerated electron beam or excitation by ultraviolet / visible light in a range of 140 to 480 nm. 11. The method for producing an oxide according to claim 1, wherein a compound of a raw material element constituting the oxide composition is mixed, and the mixture is baked after pressure molding. Manufacturing method. 12. The method according to claim 11, wherein calcination is performed before pressure molding. 13. In a reducing atmosphere or air, 1150
The method according to claim 11 or 12, wherein the firing is performed at a temperature of 1550C.