JP2002020744A - Fluorescent substance with afterglow tendency - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aluminate fluorescent substance with afterglow tendency having high phosphorescent luminance and improved in heat resistance, water resistance and productivity. SOLUTION: This fluorescent substance with afterglow tendency activated with bivalent europium is characterized by that its chemical compositional formula: (M1-p-qEUpQq)O.n(Al1-mBm)2O3.kP2O55 satisfies the following requirements: 0.0001<=p<=0.5, 0.0001<=q<=0.5, 0.5<=n<=1.5, 0.0001<=m<=0.5, 0<k<=0.2, and 0.0002<=p+q<=0.75 (in the formula, M is at least one selected from the bivalent metal group consisting of Mg, Ca, Sr, Ba and Zn; Q is a coactivator, being at least one element selected from the group consisting of Mn, Zr, Nb, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an afterglow phosphor which can be used as a phosphorescent phosphor, and more particularly to an aluminate afterglow phosphor having excellent heat resistance and water resistance.

[0002]

2. Description of the Related Art Some fluorescent materials have afterglow in a dark place for a relatively long time when illuminated with sunlight or artificial lighting, and this phenomenon can be repeated many times. Called phosphor. In recent years, as social life has become more sophisticated and complex, interest in disaster prevention has further increased, and in particular, the use of phosphorescent phosphors that glow in dark places in the field of disaster prevention has been expanding. Recently, phosphorescent phosphors have been mixed into plastics and processed into plates, sheets, etc.,
Applications are expanding in various fields.

[0003] Conventionally, ZnS: Cu has been used as a phosphorescent phosphor.
Phosphors have been used but have not always been satisfactory. This is because this phosphor has the following essential disadvantages. One is that the phosphorescence brightness (the brightness of the afterglow) is not so high that it can be confirmed for several tens of hours. The other problem is that there is a problem that photodecomposition is caused by ultraviolet rays, colloidal zinc metal is deposited on the phosphor crystal surface, the appearance is changed to black, and the phosphorescent luminance is significantly reduced.
Such deterioration is particularly likely to occur under high-temperature and high-humidity conditions. Usually, to improve this defect, the surface of the ZnS: Cu phosphor is subjected to a light-resistant treatment, but it is difficult to completely prevent it. Therefore, the ZnS: Cu phosphor must be avoided from being used in places exposed to direct sunlight, such as outdoors.

It has recently been reported that zinc sulfide phosphors exhibit afterglow by containing rare earth ions. ("Rare earth effect in nonrioactivenight lu
minous phosphor ZnS: Pb, Cu "Hunan Shifan Daxue, Zira
n Kexue XuebaoVol.14, No.1, page47-51 1991, X May and
M. Hong, (Acta Scientiarium Naturalium Univ. Normalis
Hunanensis))

Further, it has been reported that a Bi or Cu activated calcium sulfide phosphor contains a rare earth element to exhibit afterglow. ("Study on effect of rare e
arthin blue-purple night-luminous phosphor CaS: Bi,
Cu "Hunan Shifan Daxue, Ziran Kexue XuebaoVol.15, N
o.2, page145-148,1992, X Mao, S.Lian and Z.Wu (Huna
n Normal Univ., Hunan, CHN))

However, since these phosphors are sulfides, they have the above-mentioned disadvantages, and it is easy to imagine that they cannot be used outdoors.

On the other hand, MA activated with divalent Eu
In the compound represented by l ₂ O ₄ , M is a phosphorescent phosphor whose mother crystal is a compound composed of at least one metal element selected from the group consisting of calcium, strontium, and barium. Is disclosed.
This phosphor solves the above-mentioned essential disadvantages of the zinc sulfide phosphor. The base material of this phosphor is disclosed in US Pat. No. 2,392,814 and US Pat. No. 3,294,699.
It is already known in the issue.

[0008] Divalent Eu shows a broad spectrum emission due to indirect transition, and is affected by the preparation conditions and the structure of the host crystal.
Depending on whether it is borate or aluminum gallate,
It is generally known that light is emitted in a wide range from the ultraviolet region to yellow.

The present inventors have developed an afterglow phosphor which is activated by divalent europium and co-activated with a specific rare earth element, using an alkaline earth metal salt of boroaluminic acid as a phosphor matrix. Filed for a US patent and was granted a patent. (USP53
No. 76303) In addition, the present inventors have used the same phosphor matrix, conducted tests on a larger number of coactivators, and filed a patent application for newly obtained findings. (Japanese Patent Application No. 6-147912)

[0010]

When the phosphorescent phosphor is used by mixing it with plastic or ceramic, the phosphorescent phosphor is exposed to a temperature of about 300 to 700.degree. Therefore, there is a need for a phosphorescent phosphor that does not deteriorate in luminous performance even when there is a step of molding at such a high temperature. In addition, when used outdoors, contact with moisture is particularly likely to occur, and when used in such an environment, water resistance is also important.

[0011]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have made intensive studies on components that promote the crystal growth of the afterglow phosphor and stabilize the crystals. It has been found that the problem can be solved by including them at the same time.

That is, the afterglow phosphor of the present invention is characterized in that the chemical composition of the aluminate phosphor activated with divalent europium is in the following range. _{(M 1-p-q Eu} p Q q) O · n (Al 1-m B m)
_{2 O 3 · kP 2 O 5} 0.0001 ≦ p ≦ 0.5 0.0001 ≦ q ≦ 0.5 0.5 ≦ n ≦ 3.0 0.0001 ≦ m ≦ 0.5 0 <k ≦ 0. 2 0.0002 ≦ p + q ≦ 0.75 where M in the composition formula is at least one selected from the group of divalent metals consisting of Mg, Ca, Sr, Ba, and Zn, and Q is co-activation. Mn, Zr, Nb, Pr,
It is at least one selected from the group consisting of Nd, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu.

By further adjusting the above composition to the following specific range, the fluorescent color and the afterglow color can be selected.

In the case of preparing an afterglow phosphor emitting green light having an emission peak wavelength of around 520 nm, the following composition range is selected. That is, in the aluminate phosphor activated with divalent europium, the afterglow phosphor is mainly composed of a monoclinic crystal having a chemical composition formula in the following range. _{(M 1-p-q Eu} p Q q) O · n (Al 1-m B m)
₂ O ₃ .kP ₂ O ₅ 0.0001 ≦ p ≦ 0.5 0.0001 ≦ q ≦ 0.5 0.5 ≦ n ≦ 1.5 0.0001 ≦ m ≦ 0.5 0 <k ≦ 0. 2 0.0002 ≦ p + q ≦ 0.75 However, M in the composition formula has Sr of 70 mol% or more.

When preparing a blue-emitting afterglow phosphor having an emission peak wavelength of around 440 nm, the following composition range is selected. That is, in an aluminate phosphor activated with divalent europium, the chemical composition formula is in the following range, and the crystal structure is mainly a monoclinic system. And _{(M 1-p-q Eu} p Q q) O · n (Al 1-m B m)
₂ O ₃ .kP ₂ O ₅ 0.0001 ≦ p ≦ 0.5 0.0001 ≦ q ≦ 0.5 0.5 ≦ n ≦ 1.5 0.0001 ≦ m ≦ 0.5 0 <k ≦ 0. 2 0.0002 ≦ p + q ≦ 0.75 where M in the composition formula is 70 mol% or more of Ca.

When preparing a blue-green emitting afterglow phosphor having an emission peak wavelength of about 490 nm, the following composition range is selected. That is, in an aluminate phosphor activated with divalent europium, the chemical composition formula is in the following range, and the crystal structure is mainly an orthorhombic system. And _{(M 1-p-q Eu} p Q q) O · n (Al 1-m B m)
₂ O ₃ .kP ₂ O ₅ 0.0001 ≦ p ≦ 0.5 0.0001 ≦ q ≦ 0.5 1.5 ≦ n ≦ 3.0 0.0001 ≦ m ≦ 0.5 0 <k ≦ 0. 2 0.0002 ≦ p + q ≦ 0.75 However, M in the composition formula has Sr of 70 mol% or more.

It is preferable that the afterglow phosphor emitting blue-green light having an emission peak wavelength of about 490 nm be selected in the following composition range in terms of emission luminance and afterglow luminance. That is, in an aluminate phosphor activated with divalent europium, the chemical composition formula is in the following range, and the crystal structure is mainly an orthorhombic system. And _{(M 1-p-q Eu} p Q q) O · n (Al 1-m B m)
₂ O ₃ .kP ₂ O ₅ 0.0001 ≦ p ≦ 0.5 0.0001 ≦ q ≦ 0.5 1.7 ≦ n ≦ 1.8 0.0001 ≦ m ≦ 0.5 0 <k ≦ 0. 2 0.0002 ≦ p + q ≦ 0.75 where M in the composition formula is Sr.

The activator and coactivator introduced into the afterglow phosphor of the present invention greatly affect the fluorescent color and the afterglow luminance. Practically, each is adjusted to the following ranges.

Regarding the Eu concentration p of the activator, the Sr of the host is 0.0001 mol or more with respect to 1 mol of the phosphor.
It is adjusted to a substitution range of 0.5 mol or less. Because 0.
If the amount is less than 0001 mol, the light absorption becomes poor, and as a result, the afterglow luminance decreases. On the other hand, if the amount exceeds 0.5 mol, concentration quenching occurs and the afterglow luminance decreases. A more preferable range of p is 0.001 ≦ p ≦ 0.06, and the afterglow luminance is further increased in this range.

By introducing the co-activator, the luminescence of Eu becomes afterglow. Mn, Z as co-activator
r, Nb, Pr, Nd, Gd, Tb, Dy, Ho, E
At least one selected from the group consisting of r, Tm, Yb, and Lu is effective.

Dy is the divalent metal M of the phosphor matrix, especially Sr
Is effective for improving the afterglow, and the optimum concentration range of the Dy concentration q is 0.0005 or more and 0.03 or less.

Nd is such that the divalent metal M of the phosphor matrix is particularly Ca
Is particularly effective in improving the afterglow luminance, and the optimal range of the Nd concentration q is 0.0005 or more and 0.03 or less.

A second synergistic effect is exhibited by activating the coactivators Dy and Nd with another second.

When Dy is selected as the first coactivator, the preferred range of the Mn concentration q of the second coactivator is 0.1.
0001 or more and 0.06 or less, more preferably 0.1 or more.
The range is from 0005 to 0.02.

When Dy is selected as the first coactivator, the preferable range of the Tm concentration q of the second coactivator is 0.1.
0003 or more and 0.02 or less, more preferably 0.
The range is from 0004 to 0.01.

When Dy is selected as the first coactivator, the preferable range of the Lu concentration q of the second coactivator is 0.1.
0001 or more and 0.06 or less, more preferably 0.1 or more.
The range is from 0004 to 0.04.

When Dy is selected as the first coactivator, the preferable range of the Nb concentration q of the second coactivator is 0.1.
It is at least 0001 and at most 0.08, more preferably at least 0.08.
The range is from 0003 to 0.04.

When Dy is selected as the first coactivator, the preferable range of the Yb concentration q of the second coactivator is 0.1.
0002 or more and 0.04 or less, more preferably 0.02 or less.
The range is from 0003 to 0.01.

When Dy is selected as the first coactivator, the preferable range of the Zr concentration q of the second coactivator is 0.1.
It is 002 or more and 0.70 or less.

When Dy is selected as the first coactivator, the preferable range of the Er concentration q of the second coactivator is 0.1.
It is 0001 or more and 0.03 or less. More preferably, the range is 0.0005 or more and 0.02 or less.

When Dy is selected as the first coactivator, the preferable range of the Pr concentration q of the second coactivator is 0.1.
It is 0001 or more and 0.04 or less. A more preferable range is 0.0005 or more and 0.03 or less.

When Nd is introduced as the first coactivator, the preferable range of the Tm concentration q of the second coactivator is 0.1.
0001 or more and 0.06 or less, more preferably 0.1 or more.
The range is from 0005 to 0.02.

When Nd is introduced as the first coactivator, the preferable range of the Pr concentration q of the second coactivator is 0.1.
0001 or more and 0.06 or less, more preferably 0.1 or more.
The range is from 0005 to 0.02.

When Nd is introduced as the first co-activator below, the preferred range of the Ho concentration q of the second co-activator is 0.0001 or more and 0.06 or less, more preferably 0.1% or less. The range is from 0005 to 0.02.

When Nd is introduced as the first coactivator below, the preferred range of the Dy concentration q of the second coactivator is 0.0001 or more and 0.06 or less, more preferably 0.1 or less. The range is from 0005 to 0.02.

Regarding the base composition of the afterglow phosphor of the present invention, the afterglow characteristics are further improved by substituting a part of aluminum with boron. Boron is suitably substituted in the range of 0.0001 mol to 0.5 mol of the total number of moles of aluminum, more preferably 0.001 mol.
The range is from 5 moles to 0.25 moles, most preferably around 0.05 moles. In order to introduce boron, it is preferable to charge aluminum by subtracting an amount corresponding to the amount.

The concentration k of the phosphate compound is 0.001 or more,
The range is preferably 0.2 or less, more preferably 0.01 or more and 0.1 or less, and most preferably 0.03 or more and 0.05 or less.

The afterglow phosphor of the present invention can be used as a raw material, for example, a metal oxide such as SrO, MgO, Al ₂ O ₃ or Eu ₂ O ₃ , or CaCO ₃ , SrCO ₃ , BaCO _3.
A compound which easily becomes an oxide by firing at a high temperature such as described above is selected. Such compounds include nitrates, oxalates and hydroxides in addition to carbonates. As the boron compound, boric acid or an alkaline earth borate can be used, and boric acid is particularly preferable. Also, in order to introduce phosphoric acid into the composition of the afterglow phosphor,
Phosphoric acid, phosphoric anhydride, ammonium phosphate, phosphates of alkaline earth elements and the like can be preferably used.

The purity of the raw material greatly affects the afterglow luminance.
It is preferably at least 9.9%, more preferably at least 99.99%. Raw materials obtained by mixing these fluxes are mixed at a temperature of 1200 ° C. or more and 1600 ° C.
The afterglow phosphor of the present invention is obtained by baking at the following temperature, crushing and sieving the baked product. The mixing ratio of the raw materials is
It can be determined by mixing theoretical amounts for obtaining the desired composition.

The raw material obtained by mixing them is mixed under reducing atmosphere for 1 hour.
The afterglow phosphor of the present invention can be obtained by baking in a temperature range of 200 ° C. or more and 1600 ° C. or less, pulverizing and sieving the fired product. In addition, the mixing ratio of the raw materials can be determined by mixing theoretical amounts for obtaining a desired composition.

[0041]

The afterglow phosphor of the present invention basically emits strong light due to divalent Eu as an activator, but divalent Eu absorbs light in a wide range from visible light to ultraviolet light, and therefore has natural light. And emits light with high efficiency (fluorescence) when excited in a wide range of wavelengths. Further, Mn, Zr, Nb, P
r, Nd, Gd, Tb, Dy, Ho, Er, Tm, Y
The afterglow phenomenon appears by doping the phosphor matrix with at least one selected from the group consisting of b and Lu.

The afterglow phosphor of the present invention contains boron to improve the crystallinity of the aluminate and stabilize the emission center and the capture center to improve the afterglow time and the afterglow luminance. It can be estimated that it is working effectively. In addition, boron simultaneously acts as a flux and promotes the crystal growth of the phosphor, so that the phosphorescent luminance can be greatly improved.

When the total number of moles of the oxides of the divalent metal, activator and co-activator and the total number of moles of alumina and boric acid were approximately 1: 1, that is, n = 1, the analysis was performed by X-ray diffraction. As a result, the crystal structure becomes a SrAl ₂ O ₄ type monoclinic system, and emits green light having a peak at a wavelength of 520 nm.

However, this afterglow phosphor has poor heat resistance, and the heat resistance further worsens with the addition of boric acid. Moreover, the fired product becomes hard, and it is difficult to carry out processing such as pulverization and sieving in the subsequent steps. Become. On the other hand, heat resistance and water resistance are improved by adding and sintering a phosphoric acid compound as a composition raw material.

Most of the added boric acid forms mixed crystals with alumina and is incorporated into the phosphor composition, but a part of the excess boric acid forms mixed crystals with the phosphoric acid compound and the divalent metal to form phosphor particles. It is thought to have the function of preventing the melting reaction during the heating, which contributes to the improvement of heat resistance. In addition, since this mixed crystal is insoluble in water and coats the particle surface of the afterglow phosphor,
Provides water resistance to the afterglow phosphor.

When a phosphoric acid compound is added during the calcination of the afterglow phosphor and sintering is performed, most of the phosphor is contained in the composition as a phosphoric acid compound. In order to _examine the content and the effect on phosphorescence luminance, heat resistance and water resistance, (Sr _0.955 Eu _0.03 Dy
_{0.015) O · 0.91 (Al 0.9} 5 B 0.05) 2 O 3 · kP 2 O
_Five afterglow phosphors were prototyped, and their characteristics with respect to the content k of the phosphoric acid compound were evaluated. Here, the heat resistance and the water resistance were determined by the following methods.

Regarding heat resistance, 10 g of an afterglow phosphor was placed in a quartz crucible, oxidized and fired in a muffle furnace at 600 ° C. for 30 minutes, the phosphorescent luminance of the fired product was measured, and the afterglow fluorescence before firing was measured. The percentage of the body's phosphorescence brightness is calculated and determined as the maintenance rate.

Regarding the water resistance, 10 g of the afterglow phosphor and 200 g of pure water are put into a 250 ml plastic container, and rotated with a roller at a speed of 30 rpm for 72 hours. Next, solid-liquid separation and drying are performed, the phosphorescent luminance of the afterglow phosphor is measured, and the percentage of the phosphorescent luminance before contact with water is calculated and determined as a maintenance rate.

FIGS. 1 to 3 show the relationship between the phosphorescent luminance, heat resistance and water resistance of phosphoric acid content k based on these measurement results. As can be seen from FIG.
In a wide range of ≤0.1, the phosphorescent brightness is improved 20 minutes after the stop of the excitation, and the highest value is obtained when k is around 0.05. k>
In the range of 0.1, the phosphorescence luminance is lower than that containing no phosphoric acid compound.

From the results of the heat test shown in FIG. 2, it can be seen that the content of the phosphoric acid compound has an effect on heat resistance in a wide concentration range, and that k ≧ 0.00005 has an effect on heat resistance. 0.01 is preferable, and the range of 0.02 ≦ k ≦ 0.05 is most preferable.

The water resistance of each of the afterglow phosphors containing no phosphoric acid compound is 0%, because the phosphor crystals are destroyed and do not emit light at all. As shown in FIG. 3, the effect of phosphoric acid on water resistance covers a wide range.
In the range of 1 ≦ k ≦ 0.6, the maintenance ratio exceeds 20% and is 0.0%.
The maintenance ratio exceeds 40% in the range of 2 ≦ k ≦ 0.1, and k =
A value of around 0.05 is most preferable, especially when the maintenance ratio exceeds 50%.

Judging from these considerations, the phosphate compound concentration k is preferably in the range of 0.001 ≦ k ≦ 0.2,
The range of 0.01 ≦ k ≦ 0.1 is more preferable, and 0.0
It can be said that the range of 3 ≦ k ≦ 0.05 is most preferable. However, the value of k should be selected depending on the environment in which it is used.

As a result of analyzing the crystal structure of the phosphor when the divalent metal M is Sr by X-ray diffraction, the crystal of the afterglow phosphor containing no phosphoric acid compound is a monoclinic SrAl ₂ O ₄ crystal. Although the structure is shown, if a small amount of phosphoric acid is contained at the same time as boric acid, crystals of different types of α-Sr ₃ P ₂ O ₈ will be mixed. When the amount of phosphoric acid further increases and n / 4 ≦ k, a crystal consisting entirely of α-Sr ₃ P ₂ O ₅ is obtained. Also, if the divalent metal M is Ca, the crystal of afterglow phosphor containing no phosphate compound exhibits monoclinic structure of CaAl ₂ O _4, containing phosphoric acid as much, CaP ₂
Crystals of different types of O ₆ are mixed.

[0054]

[Example 1] SrCO was used as a phosphor material.₃
140.98 g (0.955 mol), Al ₂O₃To
88.14 g (0.865 mol), Eu₂O₃To 5.
28 g (0.015 mol), Dy₂0₃2.80 g
(0.0075 mol), H₃BO₃5.63 g
(0.091 mol), and (NH₄)₂HPO₄To
7.92 g (0.060 mol) was used as a mixed medium.
Put in a ceramic pot with lumina balls and put a roller
And mixed for 2 hours before firing the phosphor,
Get). Next, raw raw powder is put into an alumina crucible.
Fired at 1400 ° C for 5 hours in a reducing atmosphere
Get the goods. Next, the fired product is pulverized and sieved with a 200 mesh sieve.
Through the present invention (Sr_0.955EU_0.03Dy_0.015)
O ・ 0.91 (Al_0.95B_0.05)₂O₃・ 0.03P₂O₅Phosphor
Get.

The obtained phosphor excites and emits light in a wide range from the visible region to the ultraviolet region, emits light when excited by a black light and a germicidal lamp, and can be applied to a fluorescent mercury lamp and a low-pressure mercury vapor discharge lamp. Then, a test according to the use of the phosphorescent phosphor is performed according to JIS K5120.

0.5 g of an acrylic resin varnish was added to 1 g of the phosphor sample, and the mixture was kneaded sufficiently so as not to grind the sample. The sample was 100 mg / cm ^{2 on} an aluminum plate.
The test piece was applied so as to have the above thickness and dried. This test piece is used for measurement of fluorescent color, phosphorescent luminance, and light resistance.

For measurement of fluorescent color, 253.7 nm
Was applied to the sample, and the fluorescence was used to determine the spectral distribution with a spectrophotometer, and the chromaticity of the CIE color system was calculated. The fluorescent chromaticity is x = 0.248, y = 0.561, and it is apparent that the fluorescent material exhibits a green color with high visibility and has excellent basic characteristics as a phosphorescent phosphor.

For the measurement of phosphorescence luminance, see JIS Z 9100
(Method of measuring phosphorescent luminance of luminous safety sign board). After the test piece was kept in a state of blocking the external light more than 3 hours in the dark, the light of the common light source D ₆₅ to the test piece was irradiated for 4 minutes at an illuminance of 200 lux, phosphorus after stopping the irradiation after 20 minutes The light intensity is (Sr _0.955 Eu _0.03 Dy _0.015 Tm
_It was measured as a relative value with the phosphorescent luminance of the _0.003 ) O. (Al _0.95 B _0.05 ) ₂ O ₃ phosphor set to 100%. The afterglow phosphor of the present invention (Sr _0.952 Eu _0.03 Dy _{0
. 015) O · 0.91 (Al 0.95} B 0.05) 2 O 3 · 0.03P 2 O
The phosphorescence luminance of No. ₅ was 98%.

The light resistance test was carried out as follows with reference to the light resistance test method of the luminescent paint in JIS K 5671. First, the test piece was irradiated with light of a 300 W high-pressure mercury lamp as a deterioration source at a distance of 20 cm from the test piece for 100 hours, and then stored in a dark place with external light blocked for at least 1 hour.
The light of ₆₅ is irradiated for 4 minutes at an illumination of 200 lux, and the phosphorescence luminance is measured 5 minutes after the irradiation is stopped. Next, the maintenance ratio was determined as a relative value to the phosphorescence luminance after 5 minutes of the reference product not irradiated with the high-pressure mercury lamp, and the light resistance was evaluated from the results. The larger the value, the better the light resistance. The phosphorescent luminance of the conventional ZnS: Cu phosphor is 23%
In contrast, the phosphorescent luminance of the afterglow phosphor of the present invention is 95%, which is not significantly deteriorated, and is extremely excellent in light resistance, whereas the phosphorescent luminance is significantly reduced by irradiation with a high-pressure mercury lamp.

Regarding heat resistance, 10 g of an afterglow phosphor was placed in a quartz crucible, oxidized and fired in a muffle furnace at 600 ° C. for 30 minutes, and the phosphorescent luminance of the fired product was measured. The percentage of the body's phosphorescence brightness is calculated and determined as the maintenance rate. The afterglow phosphor of the present invention exhibited a retention rate of 76.6%.

Regarding the water resistance, 10 g of an afterglow phosphor and 200 g of pure water are placed in a 250 ml plastic container, and the resultant is rotated with a roller at a speed of 30 rpm for 72 hours. Next, solid-liquid separation and drying are performed, the phosphorescent luminance of the afterglow phosphor is measured, and the percentage of the phosphorescent luminance before contact with water is calculated and determined as a maintenance rate. The afterglow phosphor of the present invention exhibited a retention of 49.1%.

Comparative Example 1 (NH₄)₂HPO₄Add
Afterglow fluorescence of a comparative example in the same manner as in Example 1 except that no
Body (Sr_0.955EU_0.03Dy_0.015) O ・ 0.91 (Al
_0.95B_0.05) ₂O₃Prototype. Stop excitation for 20 minutes
The subsequent phosphorescence luminance was 61%, and the maintenance rate of the heat resistance test was 25.
1%, water resistance: 0%, no emission
Was.

Other Examples 2 to 13 in which the divalent metal M is Sr, and Comparative Examples 2 to 10 containing no phosphoric acid compound were produced in the same manner and measured in the same manner. Table 1 and Table 2 summarize the results including No. 1.

[0064]

[Table 1]

[0065]

[Table 2]

Example 14 As a phosphor material, CaC
O₃95.59 g (0.955 mol) of Al₂O₃
94.01 g (0.922 mol) of Eu₂O₃To
2.64 g (0.0075 mol), Nd₂0₃To 5.
05 g (0.015 mol), H₃BO₃6.00 g
(0.097 mol), and (NH₄)₂HPO₄To
7.92 g (0.060 mol) was used as a mixed medium.
Put in a ceramic pot with lumina balls and put a roller
And mixed for 2 hours before firing the phosphor,
Get). Next, raw raw powder is put into an alumina crucible.
Fired at 1400 ° C for 5 hours in a reducing atmosphere
Get the goods. Next, the fired product is pulverized and sieved with a 200 mesh sieve.
Through the present invention, (Ca_0.955EU_0.015Nd_0.03)
O0.97 (Al_0.95B_0.05) ₂O₃・ 0.03P₂O₅Phosphor
Get.

Other Examples 15 to 18 when the divalent metal M is Ca, Comparative Examples 15 to 18 containing no phosphate compound
Similarly, a prototype was produced in the same manner and measured in the same manner.
The results including Comparative Example 14 are summarized in Tables 3 and 4.

From these, the afterglow phosphor of the present invention is excellent in phosphorescent luminance, heat resistance and water resistance both when the divalent metal M is Sr green and when M is Ca blue. ing. In particular, the effect of the phosphoric acid compound on the water resistance is remarkable. When M is Sr, the maintenance ratio is 0% in all the comparative examples in which the phosphoric acid compound is not added, whereas the product of the present invention is greatly improved. I have.

[0069]

[Table 3]

[0070]

[Table 4]

From these, the afterglow phosphor of the present invention is excellent in phosphorescent luminance, heat resistance and water resistance both when the divalent metal M is Sr green and when M is Ca blue. ing. In particular, the effect of the phosphoric acid compound on the water resistance is remarkable. When M is Sr, the maintenance ratio is 0% in all the comparative examples in which the phosphoric acid compound is not added, whereas the product of the present invention is greatly improved. I have.

[0072]

Since the present invention is configured as described above, it has the following effects.

When the phosphorescent material is used by mixing it with plastic or ceramic, the phosphorescent material is exposed to a temperature of about 300 to 700 ° C. in order to melt them. In addition, when used outdoors, contact with moisture particularly easily occurs. On the other hand, the afterglow phosphor of the present invention has improved heat resistance and water resistance, and is also excellent in light resistance, so that it can be put to practical use under such conditions.

The afterglow phosphor of the present invention has a soft baked product produced in the calcination step, so that the subsequent steps such as pulverization and sieving can be simplified, and the yield can be improved. Furthermore, the phosphorescent brightness is improved as an unexpected effect.

[Brief description of the drawings]

FIG. 1 is a characteristic diagram showing the relationship between the phosphoric acid compound content of the afterglow phosphor of the present invention and the phosphorescence luminance 20 minutes after stopping the excitation.

FIG. 2 is a characteristic diagram showing a relationship between a phosphoric acid compound content and a retention rate in a heat resistance test of the afterglow phosphor of the present invention.

FIG. 3 is a characteristic diagram showing a relationship between a phosphate compound content and a retention rate in a water resistance test of the afterglow phosphor of the present invention.

Claims (3)

[Claims] 1. An afterglow phosphor activated by divalent europium, wherein the chemical composition formula is in the following range. _{(M 1-p-q Eu} p Q q) O · n (Al 1-m B m)
₂ O ₃ .kP ₂ O ₅ 0.0001 ≦ p ≦ 0.5 0.0001 ≦ q ≦ 0.5 0.5 ≦ n ≦ 1.5 0.0001 ≦ m ≦ 0.5 0 <k ≦ 0. 2 0.0002 ≦ p + q ≦ 0.75 where M in the composition formula is at least one selected from the group of divalent metals consisting of Mg, Ca, Sr, Ba, and Zn, and Q is co-activation. Mn, Zr, Nb, Pr,
It is at least one selected from the group consisting of Nd, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. 2. The aluminate phosphor activated by divalent europium, wherein the chemical composition formula is in the following range, and the crystal structure is mainly monoclinic. Item 20. An afterglow phosphor according to item 1. _{(M 1-p-q Eu} p Q q) O · n (Al 1-m B m)
₂ O ₃ .kP ₂ O ₅ 0.0001 ≦ p ≦ 0.5 0.0001 ≦ q ≦ 0.5 0.5 ≦ n ≦ 1.5 0.0001 ≦ m ≦ 0.5 0 <k ≦ 0. 2 0.0002 ≦ p + q ≦ 0.75 However, M in the composition formula has Sr of 70 mol% or more. 3. The aluminate phosphor activated with divalent europium, wherein the chemical composition formula is in the following range, and the crystal structure is mainly monoclinic. Item 20. An afterglow phosphor according to item 1. _{(M 1-p-q Eu} p Q q) O · n (Al 1-m B m)
₂ O ₃ .kP ₂ O ₅ 0.0001 ≦ p ≦ 0.5 0.0001 ≦ q ≦ 0.5 0.5 ≦ n ≦ 1.5 0.0001 ≦ m ≦ 0.5 0 <k ≦ 0. 2 0.0002 ≦ p + q ≦ 0.75 where M in the composition formula is 70 mol% or more of Ca.