JP2001181622A - Europium activated compound oxide fluorescent substance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a new chemically stable fluorescent substance emitting light in high brightness under various excitations. SOLUTION: This europium activated compound oxide fluorescent substance is characterized in that the fluorescent substance is represented by the composition formula 6(M1-x,Eux)O.yR2O3.2AO2 (M is one or more kinds of alkaline earth metal elements selected from the group of Ca, Sr and Ba; R is one or more kinds of metal elements selected from the group of Ga, Al and In; A is one or more kinds of metal elements selected from Si and Ge; (x) and (y) are perpectively a number in a range of 1×10-3<=x<=2×10-1 and a number in a range of 9<=y<=11).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a phosphor. More specifically, the present invention relates to a europium-activated composite oxide phosphor that emits blue light with high brightness when excited by electromagnetic waves such as ultraviolet rays, electron beams, and X-rays, particularly ultraviolet rays.

[0002]

2. Description of the Related Art As is well known, metal oxides, sulfides,
Various phosphors that emit near-ultraviolet light to visible light when excited by electromagnetic waves such as ultraviolet rays, electron beams, and X-rays have been developed using oxysulfides, halides, etc. as host crystals, and fluorescent lamps, CRTs, PDPs, etc. Displays, radiographic intensifying screens,
It is widely used for fluorescent tiles for indoor and outdoor decorations, etc.With the diversification of uses of phosphors and their high functionality, there is a need for phosphors that are higher in brightness and chemically stable in each use environment. Have been.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a new chemically stable phosphor which emits light with high luminance under various excitations.

[0004]

In order to achieve the above object, the present inventors have applied various rare earth elements to inorganic oxide crystals of various oxides which are relatively chemically stable and have good durability. As a result of an attempt to activate the lanthanide element, in particular, a lanthanide element, in particular, a composite oxide crystal composed of oxides of alkaline earth metal elements, group III and group IV elements,
It has been found that a europium valent element is efficiently doped as an activator and emits high-intensity blue light when excited with ultraviolet light or an electron beam, leading to the present invention.

That is, the present invention has the following constitution (1) A europium-activated composite oxide phosphor represented by the following composition formula: _{6 (M 1-x, Eu} x)
O.yR ₂ O ₃ .2AO ₂ (where M is one or more alkaline earth metal elements selected from the group consisting of Ca, Sr and Ba, and R is G
a, at least one metal element selected from the group of Al and In, A is at least one metal element selected from Si and Ge, and x and y are each 1 × 10
⁻³ ≦ x ≦ 2 × 10 ⁻¹ and 9 ≦ y ≦ 11. )

(2) The above x and y are each 5 × 1
The europium-activated composite oxide phosphor according to the above (1), wherein the number is in the range of 0 ⁻³ ≦ x ≦ 1 × 10 ⁻¹ and 9 ≦ y ≦ 10. (3) M is Sr, R is Al, and A is Si
The europium-activated composite oxide phosphor according to the above (1) or (2), wherein:

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The phosphor of the present invention is manufactured as follows. 1) Compound of M element such as oxide or carbonate, nitrate, sulfate, halide, etc. of M element which can be easily converted to oxide of M element at high temperature 2) Oxide, carbonate or nitrate of R element , Sulfates, halides, etc., compounds of the R element which can easily be converted to oxides of the R element at high temperatures. 3) Oxides of the A element or A, such as carbonates, nitrates, sulfates, halides, etc. Compound of element A which can be converted to element oxide 4) Compound of element Eu which can be easily converted to oxide of element Eu at high temperature, such as oxide or carbonate, nitrate, sulfate and halide of element Eu

[0008] The above four kinds of phosphor materials to stoichiometrically _{of, 6 (M 1-x,} Eu x) O · yR 2 O 3 · 2AO 2
Wherein M is one or more alkaline earth metal elements selected from the group consisting of Ca, Sr and Ba, and R is Ga, Al
And In is one or more Group III elements selected from the group of In, A is one or more Group IV elements selected from Si and Ge, and x and y are each 1 × 10 ⁻³ ≦
It is a number in the range of x ≦ 2 × 10 ⁻¹ and 9 ≦ y ≦ 11.
The same applies to the above), and the mixture is mixed well with a mixer such as a ball mill or the like, together with water or ethyl alcohol, etc., in order to increase the uniformity of mixing of each phosphor raw material. The raw materials of the phosphors of the present invention are obtained by thoroughly mixing the respective phosphor raw materials of (1) to (4) by a wet method, followed by drying and the like.

In order to promote crystal growth and to improve emission luminance, these phosphor raw material mixtures contain 1 to 10% by weight of an alkali metal or alkaline earth metal halide. Alternatively, a relatively low melting point compound such as an ammonium salt or a boron compound may be added and mixed as a flux.

The mixture of the phosphor raw materials is filled in a heat-resistant container such as an alumina crucible and fired in a reducing atmosphere such as an inert gas such as air, argon or nitrogen, or a nitrogen gas containing hydrogen. In particular, when calcination is performed using an inert gas containing 1 to 5% hydrogen, Eu as an activator is obtained.
Is maintained in the state of Eu ⁺² ions, so that it is easy to dope the host crystal, and a phosphor having a higher blue emission intensity can be obtained, which is preferable. Note that the phosphor raw material mixture may be preformed under pressure into pellets or the like, and the pellets may be packed in a heat-resistant container, fired, and then ground after firing.

The firing depends on the amount of the raw material charged.
It is only necessary to go to the line at a temperature of 000 ° C. to 1700 ° C. for 2 hours to 50 hours.
It is more preferable to carry out at 1650 ° C. for 5 hours to 30 hours.
The firing may be performed once, but it is preferable to repeat the firing, cooling, and pulverizing steps of the fired material, which has been fired once, by sequentially increasing the firing temperature, in terms of light emission luminance.

Next, the fired product is cooled, pulverized, washed with water,
After drying and sieving, for example, 6 (Sr, Eu) O.
9Al ₂ O ₃ .2SiO ₂ , 6 (Sr, Eu) O.10
Al ₂ O ₃ .2SiO ₂ , 6 (Sr, Eu) O.11A
l ₂ O ₃ · 2SiO ₂ , 6 (Ca, Sr, Eu) O · 1
0Al ₂ O ₃ .2SiO ₂ , (Ba, Sr, Eu) O.
_{10Al 2 O 3 · 2SiO 2,} 6 (Sr, Eu) O · 1
_{0 (Al, Ga) 2 O} 3 · 2SiO 2, 6 (Ca, E
_{u) O · 10 (Al,} Ga) 2 O 3 · 2SiO 2, 6
(Sr, Eu) O.10 (Al, In) ₂ O ₃ .2Si
O ₂ , 6 (Ca, Eu) O · 10 (Al, In) ₂ O ₃
.2SiO ₂ , 6 (Sr, Eu) O.10Al ₂ O _3.
2 (Si, Ge) O ₂ , 6 (Ca, Sr, Eu) O · 1
_{0 (Al, Ga) 2 O} 3 · 2SiO 2 etc., its composition formula _{{6 (M 1-x,} Eu x) O · yR 2 O 3 · 2AO 2}
The phosphor of the invention can be obtained.

In the phosphor of the present invention, the composition # 6 (M
_{1-x, Eu x) O} · yR 2 O 3 · 2AO 2} in _{R 2}
When the number of moles of the O ₃ component (y value) is less than 9, or when the R ₂ O ₃ component is excessively increased and the y value is increased to more than 11, the emission luminance of the obtained phosphor is temporarily reduced. The number of moles of the R ₂ O ₃ component in the phosphor component (y value)
Is preferably in the range of 9 ≦ y ≦ 11, and 9 ≦ y ≦ 1
More preferably, the number is in the range of 0. In some cases, for example, M ₆ R ₁₈ A ₂ O ₃₇ or the like may be contained in the phosphor host crystal of the present invention obtained by preparing and firing the phosphor raw material according to the above composition formula. In some cases, it is confirmed that the crystal phase of the R ₂ O ₃ component is mixed in the main crystal phase of the composition. In this case, the crystal phase of M ₆ R ₁₈ A ₂ O ₃₇ is also the main crystal phase. A slight excess of R _{2 in the} composition stoichiometrically M ₆ R ₁₈ A ₂ O ₃₇
O ₃ component crystal phase are mixed, the composition _{{6 (M 1-x,} E
When u _x ) O.yR ₂ O ₃ .2AO ₂ } is used, a phosphor with high luminance can be obtained.

FIG. 1 shows that M, R and A are Sr, Al
And Si, and the composition formula whose y value is 10 is 6 (Sr
_{0.99, Eu 0.01) O · 10Al} 2 O 3 · 2Si
FIG. 1 illustrates an X-ray diffraction diagram of the phosphor of the present invention, which is O _{2. As} can be seen from FIG. However, the host crystal has a crystal of Sr ₆ Al ₁₈ Si ₂ O ₃₇ as a main phase, and two phases of this and Al ₂ O ₃ are mixed. In the case of this phosphor as well, the main crystal phase is Sr. ₆ Al
Constituting the phosphor in a state where excess Al ₂ O ₃ is present in ₁₈ Si ₂ O ₃₇ is effective in increasing the luminance of the phosphor. It has been confirmed that the same applies to the phosphor of the present invention in which M, R and A each represent a metal element other than Sr, Al and Si.

In the phosphor of the present invention, the amount (x value) of Eu, which is an activator element, is determined by the kind of the metal element constituting and the number of moles of the R ₂ O ₃ component in the excess component (y value). Irrespective of the value), the emission luminance of the obtained phosphor is approximately 1 ×
10 ⁻³ ≦ x ≦ 2 × 10 ⁻¹ , more preferably 5 × 10
^{It is preferable to set −3} ≦ x ≦ 1 × 10 ⁻² . In the phosphor of the present invention, M, R and A of the metal elements are Sr and A, respectively.
In particular, a phosphor having a high luminance can be obtained when they are 1 and Si.

FIG. 2 shows that the composition formula is 6 (Sr _0.99 , Eu
FIG. 2 illustrates an emission spectrum when the phosphor of the present invention, which is _0.01 ) O.10Al ₂ O ₃ .2SiO ₂ , is excited by an electron beam at an accelerating voltage of 15 kV. As can be seen from FIG. Showed high-intensity blue light emission by electron beam excitation. In addition, this phosphor is an ultraviolet ray having a wavelength of 254 nm,
Also when excited by vacuum ultraviolet rays having a wavelength of 146 nm and X-rays having an X-ray tube voltage of 80 kV, blue light emission having the same emission spectrum distribution as when excited by an electron beam was exhibited.

In the phosphor of the present invention, even when the elements M, R, and A constituting the base are other than Sr, Al, and Si, the emission intensity varies, but the emission spectrum distribution is illustrated in FIG. Blue light emission having a spectrum distribution similar to that of the sample was shown.

The phosphor of the present invention obtained as described above can be repeatedly irradiated with electromagnetic waves such as ultraviolet rays, electron beams and X-rays.
In particular, there was no significant change in composition or emission intensity, and it was confirmed that the composition was chemically stable.

[0019]

Next, the present invention will be described by way of examples. (Example 1) 175.4 g of SrCO ₃ 183.6 g of Al ₂ O ₃ 24.0 g of SiO ₂ 2.1 g of Eu ₂ O ₃ 2.1 g of each of the above phosphor materials was weighed out and sufficiently mixed with a stirring mixer. This mixture was tightly packed in an alumina heat-resistant container and fired in a gas atmosphere type electric furnace. The firing was performed at 1600 ° C. for 24 hours in an atmosphere of argon (Ar) gas. This calcined product is pulverized and sieved to give a composition of 6
_{(Sr 0.99, Eu 0.01) O} · 9Al 2 O 3 · 2
A phosphor of SiO ₂ was obtained. When this phosphor was excited by a 15 kV electron beam, it emitted blue light. This phosphor emitted blue light not only when excited by an electron beam, but also when excited by an ultraviolet ray or an X-ray in the same manner as when excited by an electron beam.

(Example 2) Of each phosphor material, 183.
The composition was changed to 6 (Sr) in the same manner as in Example 1 except that 204.0 g of Al ₂ O ₃ was used instead of 6 g of Al ₂ O _{3.
0.99, Eu 0.01) O · 10Al} 2 O 3 · 2Si
O ₂ phosphor was obtained. The X-ray diffraction diagram of the obtained phosphor is as shown in FIG. 1. When this phosphor was excited by an electron beam of 15 kV, it emitted blue light having the emission spectrum shown in FIG. This phosphor emitted blue light under any of 15 kV electron beam, ultraviolet excitation, and X-ray excitation. The emission luminance of this phosphor showed a bright blue emission that was about 30% higher than that of the phosphor of Example 1 at any excitation.

Example 3 CaCO ₃ 36.0 g SrCO ₃ 120.4 g Al ₂ O ₃ 142.8 g Ga ₂ O ₃ 112.4 g SiO ₂ 24.0 g Eu ₂ O ₃ 4.2 g Each of the above as a phosphor material Raw materials are weighed and the mixture is
Except for baking at 1650 ° C. for 20 hours in an atmosphere of argon (Ar) gas containing 1% hydrogen (H ₂ ) gas, the composition was 6 (Ca _0.3 , Sr) in the same manner as in Example 1.
_{0.68, Eu 0.02) O · 10} (Al 0.7, Ga
_0.3 ) ₂ O ₃ · 2SiO ₂ phosphor was obtained. When this phosphor was excited by a 15 kV electron beam, it emitted blue light. This phosphor can be excited by ultraviolet light or X
In the line excitation, blue light emission was exhibited in the same manner as in the case of excitation by an electron beam.

[0022] was weighed each raw material (Example _{4) SrCO 3 175.4g Al 2 O} 3 204.0g SiO 2 12.0g GeO 2 21.7g Eu 2 O 3 2.1g phosphor materials, that The mixture
Except for baking at 1650 ° C. for 20 hours in an atmosphere of argon (Ar) gas containing 1% hydrogen (H ₂ ) gas, the composition was 6 (S
_{r 0.99, Eu 0.01) O ·} 10Al 2 O 3 · 2
A phosphor of (Si _0.5 , Ge _0.5 ) O ₂ was obtained. When this phosphor was excited by a 15 kV electron beam, it emitted blue light. This phosphor emitted blue light not only when excited by an electron beam, but also when excited by an ultraviolet ray or an X-ray in the same manner as when excited by an electron beam.

[0023] (Example _{5) SrCO 3 146.1g Al 2 O} 3 119.0g In 2 O 3 138.8g SiO 2 20.0g Eu 2 O 3 1.8g NH 4 F 5.0g above as a phosphor raw material Weigh each ingredient and mix the mixture
It is baked at 1600 ° C. for 22 hours in an atmosphere of argon (Ar) gas containing 1% hydrogen (H ₂ ) gas to have a composition of 6 (Sr _0.99 , Eu _0.01 ) O · 10 (Al
A phosphor of _0.7 , In _0.3 ) ₂ O ₃ .2SiO ₂ was obtained. This phosphor emitted blue light when excited by an electron beam, ultraviolet light, or X-ray.

[0024]

According to the present invention, there is provided a novel phosphor which emits blue light with high luminance when excited by electromagnetic waves such as ultraviolet rays, electron beams, X-rays, etc. Was completed.

[0025]

[Brief description of the drawings]

FIG. 1 is a graph illustrating a powder X-ray diffraction diagram of a phosphor of the present invention.

FIG. 2 is a graph illustrating an emission spectrum of the phosphor of the present invention.

Claims (3)

[Claims] 1. A europium-activated composite oxide phosphor represented by the following composition formula: _{6 (M 1-x, Eu} x) O · yR 2 O 3 · 2AO 2 ( In the formula, M is Ca, is one or more alkaline earth metal elements selected from the group of Sr and Ba, R Is G
a, at least one metal element selected from the group of Al and In, A is at least one metal element selected from Si and Ge, and x and y are each 1 × 10
⁻³ ≦ x ≦ 2 × 10 ⁻¹ and 9 ≦ y ≦ 11. ) 2. The x and y are each 5 × 10
The europium-activated composite oxide phosphor according to claim 1, wherein the number is within a range of ⁻³ ≦ x ≦ 1 × 10 ⁻¹ and 9 ≦ y ≦ 10. 3. The method according to claim 1, wherein M is Sr, R is Al,
3. The europium-activated composite oxide phosphor according to claim 1, wherein A is Si.