JP2000144129A - Phosphorescent material capable of being excited with visible light and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an excellent phosphorescent material having high brightness and afterglow for a long time, capable of being excited with visible light, and capable of resisting to outdoor employment for a long period. SOLUTION: This phosphorescent material is obtained by adding Eu as an activator and at least one element selected from Ti, Zr, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Nb, Mo, Ta, W, Bi, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu as a coactivator to a compound of the formula: MA14O7 (M is at least one metal element selected from the group consisting of Mg, Ca, Sr and Ba) as a matrix material. The phosphorescent material can be excited with visible light, has higher luminance than commercial products, and exhibits superafterglow.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel phosphorescent phosphor which is excited by visible light and has an extremely long afterglow and high luminance, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, phosphorescent phosphors include CaS:
Sulfide phosphors such as Bi and ZnS: Cu are well known. However, these sulfide phosphors are chemically unstable and have many practical problems, such as poor light resistance, and are difficult to use outdoors. Therefore, SrAl ₂ O
_3: Eu, Dy _{and, Sr 4 Al 14 O 25:} Eu, Dy, or, CaAl ₂ O _3: Eu, the oxide phosphorescent phosphors such as Nd have been developed for chemical stability and light resistance Has been greatly improved. However, these phosphorescent phosphors
It is necessary to be excited by high-energy ultraviolet rays, and there is a problem that it is difficult to be excited by visible light which occupies most of sunlight. In addition, in order to expand the area of use of the phosphorescent phosphor, at present, longer afterglow and higher luminance are required.

[0003]

DISCLOSURE OF THE INVENTION The present invention has an afterglow and a high luminance for a much longer time than a commercially available oxide phosphorescent phosphor, and is excited with visible light having low energy. It is an object of the present invention to provide an excellent phosphorescent phosphor having a light resistance capable of withstanding the outdoor use for a long period of time and a method for producing the same.

[0004]

The luminous phosphor of the present invention for solving the above problems is a compound represented by MAl ₄ O ₇ (where M is a group consisting of Mg, Ca, Sr and Ba). (At least one or more selected metal elements) as a base material, and as an activator, 0.0001 mol% to 20 mol%, more preferably 10 mol% or less, of Eu is added to the metal element represented by M. As an agent, Ti, Zr, V, Cr, Mn, Fe, Co, Ni,
Transition metals of Cu, Zn, Nb, Mo, Ta, W, Bi,
And La, Ce, Pr, Nd, Sm, Gd, Tb,
At least one or more of the rare earth elements of Dy, Ho, Er, Tm, Yb, and Lu are added to the metal element represented by M in an amount of 0.0001 mol% or more and 20 mol% or less. is there.

When the phosphorescent phosphor is made of a compound represented by SrAl ₄ O ₇ as a base material and Eu is added as an activator, Dy is suitable as a co-activator. Eu is more than 0.01mol% and 1mo
1% or less, and Dy of the co-activator is more preferably added in an amount of 0.01 mol% or more and 1 mol% or less. Also,
When a compound represented by CaAl ₄ O ₇ is used as a base material and Eu is added as an activator, N is used as a co-activator.
b or Dy is preferable. In this case, Eu as an activator is added in an amount of 0.01 mol% or more and 1 mol% or less, and Nb or Dy of a co-activator is added in an amount of 0.01 mol% or more and 1 mo.
It is more preferable to add 1% or less.

Further, the method for producing a phosphorescent phosphor of the present invention uses a compound represented by MAl ₄ O _{7 as} a host material, and uses 0.000 as a activator for a metal element representing Eu as M.
1 mol% or more and 20 mol% or less, and Ti, Zr, V, Cr, Mn, Fe, Co,
Transition metals of Ni, Cu, Zn, Nb, Mo, Ta, W, Bi, and La, Ce, Pr, Nd, Sm, Gd,
After adding and mixing at least one or more of the rare earth elements of Tb, Dy, Ho, Er, Tm, Yb, and Lu with respect to the metal element represented by M, the reduction is performed. 800 to 17 in atmosphere
It is characterized by firing at 00 ° C.

In the above-mentioned production method, when a compound represented by SrAl ₄ O ₇ is used as a base material, Eu is added as an activator, and Dy is added as a co-activator, the compound is placed in a reducing atmosphere (Ar + 5% H ₂ , 130 at 1 l / min)
A method of firing at 0 ° C. for 4 hours is preferable. In addition, CaA
When a compound represented by l ₄ O ₇ is used as a base material, Eu is added as an activator, and Nb or Dy is added as a co-activator, the compound is placed in a reducing atmosphere (Ar + 5% H ₂ , 1 l / m ₂₎ .
The method of baking at 1300 ° C. for 4 hours in (in) is preferable.

According to the phosphorescent phosphor of the present invention and the method for producing the phosphor of the present invention, the phosphorescent phosphor has a much longer afterglow and a higher luminance than a commercially available oxide phosphorescent phosphor. An excellent phosphorescent phosphor that can be excited by visible light and has light resistance that can withstand outdoor use for a long time can be obtained.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The phosphorescent phosphor of the present invention is constituted by adding an activator and a co-activator to a base material, wherein the base material is a compound represented by MAl ₄ O ₇ (however, M is M
g, at least one metal element selected from the group consisting of Ca, Sr, and Ba). It has been found that the persistence and brightness when using them are higher than other substances, but among them, SrAl ₄ O ₇ or CaAl ₄ O ₇ is particularly suitable.

When an activator and a co-activator are added to the above-mentioned base material, the afterglow and the luminance can be remarkably improved. In order to dope the activator and the co-activator, the activator and the co-activator are mixed well with the base material in the form of oxides, carbonates, acetates, and nitrates. This is achieved by firing at a high temperature of 1700 ° C. for 30 minutes or more. Further, a flux such as boric acid or boron oxide is 0.1
By adding from 20 mol% to 20 mol%,
Afterglow and luminance can be improved.

Eu is used as the activator material, and Ti, Zr, V, Cr, M is used as the coactivator material.
n, Fe, Co, Ni, Cu, Zn, Nb, Mo, T
a, W, Bi transition metals, and La, Ce, Pr,
Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Y
One or more of the rare earth elements b and Lu can be used, but the optimum coactivator differs depending on the composition of the base material. For example, if the base material is SrAl ₄ O
₇ : In the case of Eu, Dy is effective as a co-activator,
In the case of CaAl ₄ O ₇ : Eu, Nd or Dy is suitable.

The amount of the activator and the material to be the co-activator is 0.0001 to 20 mol with respect to the metal element represented by M.
It can be selected in the range of 1%. It is 0.0001
When the amount is less than mol%, the afterglow and the luminance are insufficient. On the other hand, when the amount is 20 mol% or more, the crystal structure of the base material cannot be maintained, and the afterglow and the luminance decrease, which is not suitable for practical use. .

In the present invention, in the base material represented by MAl ₄ O ₇ , the metal element corresponding to M is
Regarding at least one or more metal elements selected from Mg, Ca, Sr, and Ba, Eu as an activator
As a co-activator, at least one or more of the above-mentioned various transition metals and various rare earth elements can be arbitrarily selected and added. Alternatively, as the co-activator, the various transition metals can be used. And / or at least one or more elements within an arbitrarily limited range among various rare earth elements can be arbitrarily selected and added.

[0014]

Examples of the present invention will be described below. Powder samples were prepared in order to examine the afterglow, luminance and excitation spectrum of the phosphorescent phosphor according to the present invention. The test powder sample is
0.7 m serving as activator for SrAl ₄ O ₇ which is a base material
ol% of Eu and 0.3 mol% of Dy serving as a co-activator
In a reducing atmosphere (Ar + H ₂ , 5%)
After sintering at 1300 ° C. for 4 hours, it was pulverized to obtain a phosphorescent phosphor powder.

FIG. 1 shows an excitation spectrum and an emission spectrum of the powder sample. From the figure, it is clear that the peak wavelength of the excitation spectrum is 427 nm, and it is excited by visible light. This SrAl ₂ O ₄ : E
The afterglow of the u, Dy phosphor was compared with the afterglow of a commercially available aluminate compound phosphorescent phosphor (manufactured by Nemoto Special Chemical Co., Ltd., product name: N Luminescent (Luminova)). ,
As shown in FIG. The measurement of the afterglow characteristic was performed using 1.00 g of phosphor powder.
Was irradiated with ultraviolet rays (wavelength: 365 nm) for 10 minutes, and afterglow was measured using a photomultiplier tube.
As is clear from FIG. 2, the sample powder SrAl
The luminance of the ₄ O ₇ : Eu, Dy phosphor is higher than that of a commercially available product, and the decay is slow.

Further, this SrAl ₄ O ₇ : Eu, Dy
FIG. 3 shows the results of examining the thermoluminescence characteristics (glow curve) from room temperature to 250 ° C. when the phosphor was stimulated with light. From this figure, it can be seen that the thermal luminescence of the present phosphor has peaks at 85 ° C. and 166 ° C., the amount of light emission is larger than that of a commercially available phosphorescent phosphor, and the peak is also on the high temperature side. From this, S
It is considered that the rAl ₄ O ₇ : Eu, Dy phosphor has high luminance, and the deep trap level increases the time constant of afterglow, contributing to long-term light storage.

[0017]

As described in detail above, according to the present invention, a new phosphorescent phosphor which is excited by visible light, has high luminance and exhibits super-persistence, and a method for producing the same can be obtained. . In addition, wide applications such as the possibility of use as a completely new light emitter can be expected due to the increase in luminance.

[Brief description of the drawings]

FIG. 1 shows a sample (SrAl ₄ O ₇ : Eu,
It is a graph which shows the excitation spectrum and emission spectrum of Dy).

FIG. 2 shows a sample (SrAl ₄ O ₇ : Eu,
It is a graph which shows the afterglow characteristic of Dy) and a commercial product luminous phosphor.

FIG. 3 shows a sample (SrAl ₄ O ₇ : Eu,
It is a graph which shows the thermoluminescent characteristic (glow curve) of Dy) and a commercial product luminous phosphor.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Kazuhiro Nonaka 807 Nonoshita, Jukucho, Tosu-shi, Saga Prefecture Inside the Kyushu Institute of Industrial Technology (72) Inventor Tadahiko Watanabe Jinocho, Tokushi, Saga Prefecture 807-1 Kyushu Institute of Industrial Technology (72) Inventor Noriyuki Yamada 807-1 Nonoshita, Sukumachi, Tosu City, Saga Prefecture F-term (reference) 4H001 CA04 XA08 XA12 XA13 XA20 XA38 XA56 YA22 YA23 YA24 YA25 YA26 YA27 YA28 YA29 YA30 YA40 YA41 YA42 YA57 YA58 YA59 YA60 YA62 YA63 YA64 YA65 YA66 YA67 YA68 YA69 YA70 YA71 YA73 YA74 YA83

Claims (4)

[Claims] (1) a compound represented by MAl ₄ O ₇ (provided that M
Is at least one metal element selected from the group consisting of Mg, Ca, Sr, and Ba) as a base material, and 0.0001 mol relative to a metal element representing Eu as M as an activator.
1% or more and 20 mol% or less, and as co-activators, Ti, Zr, V, Cr, Mn, Fe, Co, Ni,
Transition metals of Cu, Zn, Nb, Mo, Ta, W, Bi,
And La, Ce, Pr, Nd, Sm, Gd, Tb,
Visible light characterized by adding at least one or more of the rare earth elements of Dy, Ho, Er, Tm, Yb, and Lu to the metal element represented by M in an amount of 0.0001 to 20 mol%. Excited phosphorescent phosphor. 2. A compound represented by SrAl ₄ O ₇ is used as a base material, and Eu as an activator is added to Sr in an amount of 0.0001.
mol% or more and 20 mol% or less, and Dy as a co-activator in an amount of 0.0001 mol% or more to Sr2.
A phosphorescent phosphor excited by visible light, characterized by being added in an amount of 0 mol% or less. 3. A compound represented by CaAl ₄ O ₇ as a base material, and Eu as an activator is added to Ca in an amount of 0.0001 to 0.0001.
mol% or more and 20 mol% or less, and at least one of Nb and Dy as a co-activator is added in an amount of 0.0001 mol% or more and 10 mol% or less with respect to Ca. Phosphorescent phosphor. _4. A compound represented by MAl ₄ O ₇ (provided that M
Is at least one metal element selected from the group consisting of Mg, Ca, Sr, and Ba) as a base material, and 0.0001 mol relative to a metal element representing Eu as M as an activator.
1% to 20 mol% and Ti, Zr, V, Cr, Mn, Fe, Co, Ni,
Transition metals of Cu, Zn, Nb, Mo, Ta, W, Bi,
And La, Ce, Pr, Nd, Sm, Gd, Tb,
After adding and mixing at least one or more of the rare earth elements of Dy, Ho, Er, Tm, Yb, and Lu with respect to the metal element represented by M in an amount of 0.0001 mol% to 20 mol%, the mixture is mixed in a reducing atmosphere. At 800 to 1700 ° C
And producing a phosphorescent phosphor excited by visible light.