JP2001026777A - Red phosphorescent phosphor - Google Patents

Abstract

(57) [Summary] (with correction) [Problem] It has a characteristic that it emits light at 200 to 350 nm and is also excited by a black light and a germicidal lamp.
To provide a phosphorescent phosphor exhibiting red afterglow. A red phosphorescent phosphor composed of a fired body of a compound mainly containing germanate, which has a Ge-O bond activated by a transition element and a rare earth element and has a persistence characteristic with respect to red.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phosphorescent phosphor which emits red light for a certain period of time even when an excitation source used for a luminous paint or the like is cut off.

[0002]

2. Description of the Related Art Conventionally, long afterglow phosphors have been used for luminous paints and the like, and play a role different from phosphors used for cathode ray tubes and the like.

There are two types of long-persistent phosphors, self-luminous type and phosphorescent type. Among them, the self-luminous type always emits a constant light by the radiation energy of the radioactive substance contained in itself. It is. However, since a radioactive substance is used as the excitation source, there is a concern about the effect on the human body and the environment. On the other hand, the phosphorescent type is a phosphor that stores energy of the excitation light and emits light for a long time even after the excitation light is cut off.

A conventional phosphorescent phosphor is Zn
S: This is typically represented by Cu, but since it is mainly composed of sulfide, it has a problem in weather resistance and its use is limited.

On the other hand, Japanese Patent Application Laid-Open No. 7-11250 discloses a broad spectrum light emission in order to eliminate the disadvantages of the sulfide phosphorescent phosphor, and is affected by the composition of the base material and the preparation conditions. Aluminate phosphorescent phosphors using a compound represented by MAl ₂ O ₄ activated with divalent Eu or the like which emits light in a range from the region to yellow are disclosed. Here, M represents at least one metal element selected from the group consisting of Ca, Sr, and Ba. The matrix of this phosphor was previously disclosed in U.S. Pat. No. 3,294,699.

The emission of this aluminate phosphorescent light is
It varies from 400 to 520 nm depending on the composition and preparation conditions of the matrix, and exhibits violet, blue, or green afterglow,
It has been put to practical use for applications requiring only brightness for the afterglow of the phosphorescent phosphor.

However, when a phosphorescent phosphor is used for a display device or the like, afterglow of various colors is required. In particular, the emergence of a phosphorescent phosphor exhibiting red afterglow causes the afterglow of three primary colors. There is a strong demand because the development of new applications can be expected.

[0008]

SUMMARY OF THE INVENTION The present invention meets such a demand and has a characteristic that it emits light at a wavelength of 200 to 350 nm, is excited by a black light or a germicidal lamp, and has a red afterglow. To provide a type phosphor.

[0009]

According to the present invention, it has been found that a phosphor comprising a germanate activated by a transition element and a rare earth element exhibits red afterglow, It is based on the finding that the afterglow characteristics are improved by optimizing the auxiliary agent and the added flux.

That is, the present invention relates to a phosphor mainly composed of a germanate activated by a transition element and a rare earth element, which compound has a persistence characteristic with respect to a red color containing a Ge—O bond, and exhibits a red color. It is a fired body composed of a compound with a compound.

A germanate activated by a transition element and a rare earth element can store light by containing a Ge—O bond, and exhibits red afterglow when a compound exhibiting a red color is added.

Further, as the compound exhibiting red color, C
It is a compound exhibiting a red color containing any one or more of r, Mn, Sn, Pr, Sm and Eu, and the form of the compound may be any.

As the activating aid, La, Ce, N
d, Gd, Tb, Dy, Ho, Er, Tm, Yb, L
u, Sc, Ti, V, Fe, Co, Ni, Cu, Zn,
It is a compound containing any one or more of Y, Zr, Nb, Mo, Hf, Ta and W, and the form of the compound may be any.

Further, MgF is used as a flux.
₂ , MgCl ₂ , B ₂ O ₃ , AlF ₃ , KF, K ₃ PO ₄ , N
The afterglow characteristics can be further improved by adding and blending aCl and SiO ₂ .

The fired body is (100-abc) M
O ・ a (Ge _1-d Q _d ) O ₂・ bR ₂ O ₃・ cMX ₂・ eZ ・
It consists of a chemical formula represented by the general formula of fLn.

In the above general formula, a, b, c, d, e
And f indicate the following numerical values.

1 ≦ a ≦ 95 0 ≦ b ≦ 99 0 ≦ c ≦ 200 0 ≦ d ≦ 0.95 0.01 ≦ e ≦ 2 0.01 ≦ f ≦ 2 (unit: mol%) M is Mg, Ca , Sr, Ba and Zn are at least one selected from the group of divalent metals. Q is at least one selected from the group consisting of group 4A elements and group 4B elements. R is at least one selected from the group consisting of a group 3A element and a group 3B element. X is at least one selected from the group of halogen elements consisting of F, Cl, Br and I. Z is at least one selected from the group consisting of Cr, Mn, Sn, Pr, Sm and Eu. Ln is La, Ce,
Nd, Gd, Tb, Dy, Ho, Er, Tm, Yb, L
u, Sc, Ti, V, Fe, Co, Ni, Cu, Zn,
It is at least one selected from the group consisting of Y, Zr, Nb, Mo, Hf, Ta and W. As the compound having the afterglow property for the red color containing a Ge-O bond, any form of compound can be used.

The red phosphorescent phosphor of the present invention is prepared by adding a compound exhibiting a red color to a powder compound containing a Ge--O bond, mixing the mixture sufficiently, and adding the compound in a temperature range of 1250 to 1550.degree. The sintered body fired for a period of time is a fired product in a state of a powder crushed to 100 μm or less.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples.

As a raw material powder for producing a compound having an afterglow characteristic for red, MgO, CaCO ₃ , S
rCO ₃ , BaCO ₃ , ZnO, GeO ₂ , SiO ₂ and Mg as a flux for improving the afterglow characteristics
F ₂ , MgCl ₂ , AlF ₃ , KF, K ₃ PO ₄ , NaCl
As a compound exhibiting a red color, Cr ₂ O ₃ , MnC
O ₃ , SnO, Pr ₂ O ₃ , Sm ₂ O ₃ and Eu ₂ O ₃
La ₂ O ₃ , CeO ₂ , Nd ₂ O ₃ , Gd ₂
O ₃ and Tb ₂ O ₃ were prepared.

From among these raw material powders, selection was made so as to have the composition of Examples 1 to 26 shown in Tables 1 to 3,
Thoroughly mix each compound and put in a platinum crucible,
After firing in the air at 1400 ° C for 1 hour, 100
It was pulverized to not more than μm to obtain a phosphorescent phosphor. All exhibited excellent red phosphorescent fluorescence.

Each table shows the effect of each compound compound. Examples 1 to 8 shown in Table 1 are for searching for an optimal flux.

Examples 9 to 25 shown in Table 2 are for examining the effect of the amount of the sintering temperature and time on the initial strength.

Example 26 shown in Table 3 is for examining the effect of the activation aid on the initial strength.

The obtained phosphors are all 200 to 350.
Excitation light was emitted in nm, and it was also excited by a black light and a germicidal lamp, and emitted red light.

[0026]

[Table 1]

[Table 2]

[Table 3] Table 4 shows a comparative example for comparing the emission colors of the conventional aluminate phosphorescent phosphors. CaCO ₃ , SrCO ₃ , BaCO ₃ , Al ₂ O so as to have the composition of Comparative Examples 1 to ₃ .
₃ , Eu ₂ O ₃ , Nd ₂ O ₃ , and Dy ₂ O ₃ raw material powders, and the respective components are sufficiently mixed and put into a carbon crucible, and a 2% H ₂ /98% Ar atmosphere is used. 150 in
After baking at 0 ° C. for 3 hours, it was pulverized to 100 μm or less to obtain a phosphorescent phosphor.

[0027]

[Table 4] FIG. 1 shows the difference in emission color between the phosphorescent phosphor of the present invention and the conventional aluminate phosphorescent phosphor. The afterglow of the phosphorescent phosphor of Example 1 shown in Table 1 immediately after the excitation was stopped. The spectrum is shown in comparison with the conventional aluminate phosphorescent phosphors of Comparative Examples 1 to 3 shown in Table 4. In the same figure, (a) shows the phosphorescent phosphor of Example 1, which emits red light having a peak at 670 nm. (B), (c) and (d) show Comparative Example 1.
To 3 conventional aluminate phosphorescent phosphors, each having a peak at 440 to 520 nm, and emitting violet, blue and green light. From this figure, it can be seen that the phosphorescent phosphor of the present invention exhibits a red color which was not feasible with the conventional aluminate phosphorescent phosphor.

Each of the phosphorescent phosphors of the present invention has a phosphor content of 200 to 200.
It emits excitation light at 350 nm and emits red light when excited by a black light or a germicidal lamp. Further, the initial strength is improved by adding an appropriate activation aid. Further, it can be seen that the contained flux promotes stabilization of the crystal structure of the phosphor and promotes particle growth, and as a result, the afterglow characteristics can be significantly improved.

FIG. 2 shows an example of the afterglow characteristic of the first embodiment. The initial intensity was measured as the afterglow characteristic. After baking in air at 1400 ° C. for 1 hour, the prepared sample is stored in a dark place for at least 5 hours in a state where external light is blocked, and then the sample is irradiated with black light for 4 minutes. Is measured. As afterglow time,
It was the time until the afterglow intensity reached the luminous limit intensity. In each of the prepared samples, the slope of the attenuation curve showed a substantially constant value. Therefore, it can be understood that the main factor governing the afterglow characteristics is the initial intensity.

[0030]

As described above, the phosphorescent phosphor of the present invention can emit red light which cannot be realized by the conventional aluminate phosphorescent phosphor, and has great value when used in display devices and the like. is there.

[Brief description of the drawings]

FIG. 1 shows the difference in emission color between a phosphorescent phosphor of the present invention and a conventional phosphorescent aluminate phosphor by an emission spectrum.

FIG. 2 shows an example of the afterglow characteristic of the phosphorescent phosphor of the present invention.

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Claims (5)

[Claims] 1. A red phosphorescent phosphor comprising a fired body of a compound mainly composed of germanate, which has a Ge—O bond activated by a transition element and a rare earth element and has a persistence characteristic for red. 2. A compound mainly composed of germanate,
2. The red phosphorescent phosphor according to claim 1, comprising one or more of r, Mn, Sn, Pr, Sm and Eu. 3. A compound mainly composed of germanate is used as an activator, La, Ce, Nd, Gd, Tb, Dy, H
o, Er, Tm, Yb, Lu, Sc, Ti, V, Fe,
Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, H
3. The red phosphorescent phosphor according to claim 1, comprising one or more compounds of f, Ta, and W. 4. 4. A compound mainly composed of germanate is used as a flux with MgF ₂ , MgCl ₂ , B ₂ O ₃ , Al
_{F 3, KF, K 3 PO} 4, NaCl and red phosphorescent phosphor according to any one of claims 1 to 3 comprising SiO _2. 5. (100-abc) MO · a (Ge
_1-d Q _d ) consists of a chemical formula represented by the general formula of O ₂ · bR ₂ O ₃ · cMX ₂ · eZ · fLn, wherein a, b, c, d, e and f are
In the numerical range of 1 ≦ a ≦ 95 0 ≦ b ≦ 990 0 ≦ c ≦ 200 0 ≦ d ≦ 0.95 0.01 ≦ e ≦ 2 0.01 ≦ f ≦ 2 (unit: mol%), M is at least one selected from the group of divalent metals consisting of Mg, Ca, Sr, Ba and Zn; Q is at least one selected from the group of group 4A and group 4B elements; Is at least one member selected from the group consisting of group 3A elements and group 3B elements; X is at least one member selected from the group of halogen elements consisting of F, Cl, Br and I; and Z is Cr, Mn. , Sn, Pr, Sm and Eu, at least one selected from the group consisting of La, Ce, Nd, Gd, Tb, Dy, Ho, E
r, Tm, Yb, Lu, Sc, Ti, V, Fe, Co,
Ni, Cu, Zn, Y, Zr, Nb, Mo, Hf, Ta
And at least one member selected from the group consisting of
2. The red phosphorescent phosphor according to item 1.