JP2000234088A - Luminescent material with high-speed excitation, high luminance, and low decay - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a luminescent material which has short saturation excitation time and restoration excitation time and a high initial luminance by using a specific baking product. SOLUTION: This luminescent material with high-speed excitation, high luminance, and low decay is a baking product which is represented by the formula: (SrEu)Al2O4.n[(SrEu)O.(Al1-a-bBbQa)2O3(AlO.OH)] and has an α-alumina content of 50-99% of the total alumina content; a γ-alumina content of 1-50% of the total alumina content; and a Mohs hardness of 6.2-7.5. When (n) is 1, the baking product has a specific gravity of 3.60-3.62; a body color of light yellow green; a luminescent peak wavelength of 518-522 nm: a luminescence color of green; an excitation wavelength of 200-450 nm; an excitation time (103 lux) of 10 min or shorter; an initial luminance of 6,000 mcd/m2 or higher (30 sec after the stopping of excitation); and an afterglow time of 20 hr or longer. In the formula, Q is at least one element selected from among Bi, Ca, Mg, and Mn; 0.0005<=a<=0.002: 0.001<=b<=0.35; and 1<=n<=7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-speed excitation, high-brightness, low-attenuation luminescent material, and more specifically, a high-speed excitation, high-brightness, low-attenuation property with extremely high saturation excitation time and restoration excitation time and extremely high initial brightness. The present invention relates to a light emitting material.

[0002]

2. Description of the Related Art Conventionally, copper is used to add sulfides, such as zinc sulfide.
A phosphorescent material (ZnS:Cu) obtained by activation is known.
However, in recent years, it has been much longer than the zinc sulfide-based phosphorescent material.
Materials that continue to emit light have been developed and used in various applications.
It became so. Specifically, Chinese patent application publication number CN
1053807A discloses an invention relating to a long afterglow luminescent material.
It is disclosed. This long afterglow luminescent material has the general formula m
(Sr _1-xEu_x) O・nAl₂O₃・YB₂O₃[However
, 1≦m≦5, 1≦n≦8, 0.001≦y≦0.3
5]. This long afterglow luminescent material,
Aluminum, boron, strontium and europium
Divalent oxides of
Salt as a raw material and fired at 1200°C to 1600°C
Then, in a reducing atmosphere of nitrogen and hydrogen at 1000°C to 1400°C.
It is produced by a process of reducing with air.

In addition, as an alumina-based fired body containing boron as a constituent component, US Pat. No. 5,376,303, JP-A-8-170076, and JP-A-8-127 are known.
No. 772, etc., all of which are luminescent materials having high initial brightness and long afterglow property which are excited by sunlight, artificial illumination, excitation sources such as electron beams and X-rays.

[0004]

However, these long afterglow luminescent materials actually have an afterglow time of several hours to 1 hour.
Although it was 0 hours, it was not practically sufficient, and it was desired that the initial brightness was still higher. Therefore, the inventors of the present invention, in order to solve such a problem, improved the light emitting material in which the aluminate of an alkaline earth metal of the above general formula and a rare earth metal as an activator are improved to further improve the brightness. We have succeeded in producing a light-emitting material consisting of a crystal having high and long afterglow property and applied for a patent.

After that, the present inventors further researched such a light emitting material, and while a light emitting material having particularly high brightness was desired, as a result of trial and error, surprisingly, the saturation excitation time was extremely short, We succeeded in producing a crystalline compound that has high brightness and low attenuation, and when it is attenuated and in a low brightness state, the brightness is restored by a momentary contact with the excitation source light, and the brightness is extremely high. It has been found that a luminescent material can be obtained. The present invention has been made based on this finding. Therefore, the problem to be solved by the present invention is to provide a high-speed excitation/high-luminance low-attenuation luminescent material that is extremely fast in excitation and has extremely high initial luminance.

[0006]

[In the formula, Q is at least one selected from Bi, Ca, Mg, and Mn, a is 0.0005≦a≦0.002, and b is 0.001≦b≦0. 35, and n is 1≦n≦7]

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below. A luminescent material is sunlight, fluorescent lamp, heat, shock, etc. It is a material that emits light gradually and continues to emit light for a long time. The high-speed excitation, high-brightness, low-attenuation luminescent material of the present invention is a compound represented by the general formula, has a high initial brightness, and has an extremely fast time until the excitation reaches a saturated state, and has a decay. Even in low brightness
It is a crystalline compound that has the characteristic of being restored to high brightness by momentary contact with the excitation source ultraviolet light.

The high-speed excitation, high-brightness, low-attenuation light-emitting material of the present invention is composed of strontium compound,
α-type Al ₂ O ₃ , γ-type Al ₂ O ₃ , a boron compound, a europium compound, and a compound selected from at least one of a bismuth compound, a magnesium compound or a manganese compound. After acid treatment of at least one kind with a normal acid such as carbonic acid, all raw materials are mixed, and the mixture is heated at 400° C. in the presence of a carbonaceous material.
To 1600°C over 7-10 hours,
Then, it is further characterized by firing at 1250° C. to 1600° C. for 5 hours to 3 hours, then cooling to 200° C. over 7 hours to 10 hours, pulverizing, and classifying, whereby the crystal structure is: Although it is not clear, it is not a single crystal, because it can be obtained that the excitation time is extremely fast,
It is considered that triclinic spheroidized twinned crystal bodies are formed. This luminescent material has an extremely fast excitation time,
Moreover, it has an emission color from yellow green to blue.

The high-speed excitation, high-brightness, low-attenuation luminescent material of the present invention has a firing temperature of 7-1 from 400°C to 1250°C.
The temperature rises slowly over 0 hours and then at 1250°C for 5
By firing for 3 hours to 3 hours, a fast-excitation, high-brightness, low-attenuation light-emitting material, which is a fired product in the case where n in the general formula is 1, and whose emission color is yellow green to green is obtained. Further, the firing temperature is slowly raised from 400° C. to 1600° C. over 7 to 10 hours, and then further fired at 1600° C. for 5 hours to 3 hours to obtain a fired body in the case where n in the general formula is 2. Thus, a high-speed excitation/high-luminance low-attenuation light-emitting material having a blue emission color is obtained.

The strontium compound is specifically used as a raw material for producing the high-speed excitation, high-brightness and low-attenuation luminescent material of the present invention.
Strontium carbonate, strontium oxide or salts capable of producing these oxides by heating can be used. As the aluminum oxide, a mixture of α-type alumina and γ-type alumina in a specific ratio is used. As the boron compound, boron oxide or boric acid is preferably used. Further, europium is used as an activator, and the raw material thereof may be an oxide of europium or a salt capable of producing these oxides by heating.

Furthermore, the high-speed excitation, high-brightness, low-attenuation luminescent material of the present invention has a sensitizer, which effectively absorbs external energy and absorbs the absorbed energy as a luminescent center. Is defined as a substance that is transmitted to. Therefore, the coactivator has a different action in that it is a substance that enhances the excitation effect in cooperation with the activator. Examples of the sensitizer include Bi, Ca, Mg and Mn,
As the raw material, oxides, carbonates, or salts capable of producing these oxides by heating can be used. As the bismuth compound (for example, bismuth oxide) and the calcium compound, calcium carbonate and calcium oxide are used. The magnesium compound is preferably magnesium carbonate or magnesium oxide, and the manganese compound is
Manganese oxide is preferred.

High-speed excitation, high-brightness, low-attenuation luminescent material of the present invention
Α-alumina in the material (α-Al₂O ₃) Is aluminum
50% to 99% of the total amount of sodium, and γ-type alumina (γ-
Al ₂O₃) Is 1% to 50% of the total amount of alumina.
is there. In this luminescent material, γ-type alumina and α-type alumina
When gamma-type alumina with a mina ratio of 10 to 20%,
It is possible to obtain high brightness and low attenuation.

The emission peak wavelength of this luminescent material changes from light green to blue by reducing the amounts of strontium and europium, and therefore n
When 1 is 1, a green light emission is obtained, and when n is 2, a blue light emission is obtained. As described above, the emission peak wavelength of the high-brightness long-afterglow luminescent material of the present invention varies depending on the number of n. As the number increases, the wavelength shifts from the long wavelength side to the short wavelength side and changes from green to blue. I understand that Further, in this case, by increasing the firing temperature little by little, one having a large number of n can be obtained.

The amount of boron in the present invention is 0.001≦
The range of b≦0.35 is preferable, and when b is less than 0.001, there is no effect on the low damping property of the crystal. In addition, when the amount of boron is more than 0.35, it is not preferable because the amount of boron oxide-based products in the fired body is increased and the low damping property is deteriorated. Further, the amount of the sensitizer represented by Q is 0.0005 to 0.002, and this range is preferable. When the amount is less than 0.0005, the long afterglow light-storing performance of the crystal is obtained. Has no effect on the expression of. The amount of sensitizer represented by Q is
When it is more than 0.002, it is economically useless because the amount of the crystal that enters the vacancy is fixed. The high-speed excitation, high-brightness and low-attenuation luminescent material of the present invention is extremely solid and has a Mohs hardness of 6.2 to 7.5.

The high-speed excitation/high-brightness/low-attenuation luminescent material of the present invention has the following properties.

[When n in the General Formula is 1] (1) Specific Gravity 3.60 to 3.62 (2) Body Color Light Yellow Green (3) Mohs Hardness 6.2 to 6.5 (4) Emission Peak Wavelength 518 ~ 522nm (5) Emission color green (6) Excitation wavelength 200-450nm (7) Excitation time (10 ³ lux) within 10 minutes (8) Initial brightness 6000 mcd/m ² or more (30 seconds after the stop of excitation) (9) Remaining Light time 20 hours or more

[When n in General Formula is 2] (1) Specific Gravity 3.69 to 3.71 (2) Body Color Light Yellow Green (3) Mohs Hardness 7.0 to 7.5 (4) Emission Peak Wavelength 487 ~491 nm (5) Emission color Blue (6) Excitation wavelength 200-450 nm (7) Excitation time (10 ³ lux) Within 30 minutes (8) Initial brightness 3000 mcd/m ² or more (30 seconds after stopping excitation) (9) Remaining Light time 20 hours or more

The high-speed excitation, high-brightness, low-attenuation luminescent material of the present invention can be mixed with ink or resin to produce luminescent ink or luminescent resin. The luminance of the light emitting material of the present invention is extremely higher than that of the conventional light emitting material, and can be used for display at night. For example, when used for road displays, advertisements, stationery, toys, sports equipment, etc., it absorbs light, emits the absorbed energy in the dark in the form of light, and continuously emits light for 40 to 60 hours or more. Practically 20 to 40 hours. Further, when it is used as an auxiliary light source for a liquid crystal backlight, it is possible to save the power of the power source or reduce the weight of the device.

[Operation] The high-speed excitation/high-brightness low-attenuation light-emitting material of the present invention, when used in combination with a sensitizer, has an extremely short excitation time and can instantaneously obtain a high-brightness light-emitting material.

[0020]

EXAMPLES The present invention will be further described below based on examples, but the examples are for explaining the present invention and the present invention is not limited thereto.

Example 1 SrCO ₃ 14.48 g, α
-Al ₂ O ₃ 8.63 g, γ-Al ₂ O ₃ 1.423
g and H ₃ BO ₃ 0.866 g are prepared. Eu ₂ O ₃ (0.0005 mol) 0.176 g as a raw material for the activator,
BiO (0.0005 mol) 0.1 as raw material for sensitizer
Prepare 13 g of each. Each of these raw materials was ground to an average particle size of 2 μm. Of these, SrCO ₃ and Eu
After combining with ₂ O ₃ and adding 10% aqueous carbonate solution, mix with stirring. Then, the contents are precipitated from the obtained acid-treated aqueous solution. After the precipitate is filtered and separated, the precipitate is dried at 120° C. for 4 hours. The dried product thus obtained was pulverized to an average particle size of 2 μm. Α-Al ₂ O ₃ was added to this dry powder and mixed well to obtain a uniform mixture. Further, γ-Al ₂ O ₃ , H ₃ BO ₃ and BiO, which are the other raw materials described above, are added to this mixture, and after mixing, they are put in a crucible.

After introducing this crucible into carbon powder, the crucible is put into an electric furnace, heated from 400° C. to 1250° C. over 8 hours, and then calcined at a temperature of 1250° C. for 4 hours.
Then, after cooling to 200° C. over 8 hours, it is taken out from the electric furnace. When it reached room temperature, it was crushed with a ball mill and further classified with a 200-mesh sieve to obtain a luminescent material (1) of the present invention. The obtained luminescent material was placed under a 27 W fluorescent lamp.
Excitation at 1000 Lux for 10 minutes, and after stopping excitation, 30
When the initial luminance in seconds was measured, it was 6000 mcd/m
^{Was 2} . Light emission peak wavelength of 520 μm, light emission of dark green, afterglow time of 30 hours, specific gravity of 3.60, Mohs hardness of 6.
2. The following general formula with n=1 was obtained.

(SrEu)Al ₂ O _{4 .} (SrEu)O .(Al _0.9855
B _0.014 Bi _0.0005 ) ₂ O ₃ (AlO・OH)]

Example 2 SrCO₃12.397 g,
CaCO₃1.471 g, α-Al₂O₃8.063
g, γ-Al₂O₃1.423g, H₃BO₃0.86
Prepare 6 g. Eu as raw material of activator₂O₃0.1
76 g, Mn as raw material for sensitizer ₂O₃0.047g,
Prepare BiO 0.045g, respectively. These raw materials
Were pulverized to an average particle size of 2 μm. Of these, Sr
CO₃And Eu₂O₃15% after being combined with
Add a carbonated aqueous solution and mix with stirring. Then the acid obtained
Precipitate the contents from the treated aqueous solution. This precipitate is filtered
The precipitate is separated at 80°C to 100°C for 5 hours.
Dry for ~4 hours. The dried product thus obtained is flattened.
It was crushed to a uniform particle size of 2 μm. Α-Al to this dry powder₂O
₃Was added and mixed well to obtain a uniform mixture. Furthermore, this mixture
Γ-Al which is another raw material of the above ₂O₃, H₃BO
₃, Mn₂O₃And BiO were added and mixed, and then the crucible
Put it in the bowl.

After introducing this crucible into carbon powder, the crucible is put into an electric furnace, heated from 400° C. to 1250° C. over 8 hours, and then calcined at a temperature of 1250° C. for 4 hours.
Then, after cooling to 200° C. over 8 hours, it is taken out from the electric furnace. When it reached room temperature, it was crushed with a ball mill and further classified with a 200-mesh sieve to obtain a luminescent material (2) of the present invention. The obtained light emitting material has an emission peak wavelength of 5
20 μm, light-green color, afterglow time 40 hours, initial brightness (30 seconds after excitation stop) 6200 mcd/m ² , excitation time (1000 lux) 8 minutes, specific gravity 3.62, Mohs hardness 6.3, general formula N=1 was obtained.

(SrEu)Al ₂ O _{4 .} (SrEu)O .(Al _0.9855
B _0.014 Bi _0.0002 Mn _0.0003 ) ₂ O ₃ (AlO・OH))

Example ₃ 5.88 g of CaCO ₃ and Sr
CO ₃ 5.78 g, α-Al ₂ O ₃ 5.692 g, γ-
Al ₂ O ₃ 3.794 g and H ₃ BO ₃ 0.866 g are prepared. Eu ₂ O ₃ 0.176 g as a raw material for the activator,
Mn ₂ O ₃ 0.039 g and MgCO ₃ as a raw material for Satoshika agent
Prepare 0.021 g each. After pulverizing the above raw materials, the same acid treatment as in Example 1 was performed, and after mixing,
Put in a crucible. After introducing this crucible into carbon powder, the crucible is put into an electric furnace, heated from 400° C. to 1600° C. over 8 hours, and then fired at a temperature of 1600° C. for 4 hours. Then, after cooling to 200° C. over 8 hours, it is taken out from the electric furnace. When it reached room temperature, it was pulverized with a ball mill and further classified with a 200-mesh sieve to obtain a luminescent material (3) of the present invention. The obtained light emitting material was excellent in blue color (n=2) having an emission peak wavelength of 490 nm, an initial luminance of 3200 mcd/m ² , an excitation time (1000 lux) of 30 minutes, and an afterglow time of 50 hours or more. It was

(SrEu)Al ₂ O _{4 .} (SrEu)O .2[(Al
_0.9855 B _0.014 Mn _0.0003 Mg _0.0002 ) ₂ O ₃ (AlO・OH))

Example 4 CaCO₃ 8.337g, S
rCO₃ 2.070 g, α-Al₂ O ₃ 8.063g,
γ-Al₂ O₃ 1.423g, H₃ BO₃ 0.866g
To prepare. Eu as a raw material of the activator₂ O₃ 0.17
6 g, Mn as raw material for sensitizer ₂ O₃ 0.03g and B
Prepare 0.113 g of iO, respectively. Powder the above ingredients
After crushing, the same acid treatment as in Example 1 was applied and mixed.
Then put in a crucible. Example of crucible containing the mixture
The light-emitting material of the present invention produced in the same manner as the method of 3.
(4) was obtained. The obtained light emitting material has an emission peak wavelength of 4
90 nm, initial brightness 3200 mcd/m² , Excitation time
(1000 lux) 30 minutes, afterglow time 50 hours or more blue
An excellent color (n=2) was obtained.

(SrEu)Al ₂ O _{4 .} (SrEu)O .2[(Al
_0.9853 B _0.014 Bi _0.0003 Mn _0.0002 ) ₂ O ₃ (AlO・OH))

[Embodiment 5] SrCO₃2.170g, C
aCO₃8.337 g, α-Al₂O ₃16.126
g, γ-Al₂O₃2.846g, H₃BO₃1.73
Prepare 2 g. Eu as a raw material of the activator₂O₃0.
176 g, 0.045 g of BiO and M as raw materials for the sensitizer
gCO₃Prepare 0.025 g each. Raw materials above
Was crushed, then subjected to the same acid treatment as in Example 1 and mixed.
Then put it in the crucible.

The crucible was heated from 400° C. to 1600° C. over 10 hours, baked at a temperature of 1600° C. for 4 hours, cooled to 200° C. over 8 hours, and then taken out from the electric furnace. Crush with a ball mill at room temperature,
Classification with a 200-mesh sieve gave a luminescent material (5) of the present invention. 80% of this luminescent material under 27W fluorescent lamp
Excitation was performed at 0 Lux for 30 minutes, and after the excitation was stopped, the initial luminance from 5 seconds was measured, and the results are shown in Table 1. Further, this luminescent material emitted blue light with an emission peak wavelength of 490 nm, had an afterglow time of 30 hours, a specific gravity of 3.7, a Mohs hardness of 7.3, and n=2.

(SrEu)Al ₂ O _{4 .} (SrEu)O .2[(Al
_0.9855 B _0.014 Bi _0.0002 Mg _0.0003 ) ₂ O ₃ (AlO・OH))

Table 1 Initial Luminance Excitation Time (800Lux) 5 seconds 10 seconds 30 seconds 1 minute 5 minutes 10 minutes 20 minutes 30 minutes Comparative Example 2 110 160 480 920 2100 2260 2480 2440 (mcd/m ² ) Saturation achieved after excitation stop Rate 4.5 6.6 19.7 37.7 86.1 92.6 100 (%) Example 5 After stopping excitation 640 900 2210 2630 4120 4630 4610 (mcd/m ² ) Saturation achievement rate 13.9 19.5 47.9 57.0 89.4 100 (%)

Comparative Example 1 SrCO ₃ 14.73 g, α
-Al ₂ O ₃ 9.93 g, γ-Al ₂ O ₃ 0.10 g,
Prepare 0.22 g of H ₃ BO ₃ . As raw materials for the activator and the additional activator, Eu ₂ O ₃ 0.035 g, Dy ₂ O
₃ Prepare 0.037 g each. The above raw materials are crushed, mixed, and put in a crucible. The crucible containing the above mixture is introduced into carbon powder, then placed in an electric furnace, heated from 400°C to 1250°C over 8 hours, and then calcined at a temperature of 1250°C for 4 hours. Then, after cooling to 200° C. over 8 hours, it is taken out from the electric furnace. When it reaches room temperature, crush it with a ball mill for 20 more
Classification with a 0-mesh sieve gave a light-emitting material (6) for comparison. This luminescent material emits light of a peak wavelength of 520 μm in a light green color and has an afterglow time of 40 hours and an initial luminance of 4500 m.
Cd/m ² , excitation time (1000 lux) 30 minutes, specific gravity 3.60, Mohs hardness 6.2, and n=1 were obtained.

[Comparative Example 2] SrCO₃14.73 g, α
-Al₂O₃13.71 g, γ-Al ₂O₃5.86
g, H₃BO₃Prepare 0.94 g. Activator and additive
Eu as a raw material of the activator₂O₃0.035g, Dy₂O
₃Prepare 0.075 g each. Crush the above raw materials
Then, after mixing, put in a crucible. Pour the mixture
Raise the temperature of the pot from 400°C to 1600°C over 10 hours
And further calcination at a temperature of 1600° C. for 4 hours, then 8
Cool to 200°C over time, then remove from electric furnace
put out. Ball mill at room temperature and sieve with 200 mesh
The light emitting material (7) for comparison was obtained by classification with. This light emission
Excitation of material under 27W fluorescent lamp at 800 Lux for 30 minutes
Then, after the excitation was stopped, the initial luminance from 5 seconds was measured.
In addition, this luminescent material has an emission peak wavelength of 489 μm and a blue color.
, Afterglow time 50 hours, Mohs hardness 7.3, n=
2 was obtained. The results obtained are shown in Table 1.

[0037]

EFFECTS OF THE INVENTION The high-speed excitation/high-brightness low-attenuation luminescent material of the present invention has high initial brightness, extremely fast excitation and excellent low-attenuation due to the compound represented by the general formula, and has a yellowish green color. To emit blue light.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Xu Qian No.45 Zhajia Yuli, Changxiang store, Fengtai District, Beijing, China China (72) Inventor, Lee Pengzheng, Beijing, Fengtai District, Beijing No.45 Zhujiauli, Zhangjiazhuang, Fengtai District, Fengtai-ku, Beijing No. 45 Zhujiayuan, Zhangjiazhuang, Fengtai District, Fengtai District, Beijing, China Tai-Ku Kogyo Paint Co., Ltd. (72) Inventor Atsushi Ogura 1-40 Miyamachi, Fuchu-shi, Tokyo Chemitec Co., Ltd. (72) Inventor ▲Kure ▼ 1-40 Miyamachi, Fuchu-shi, Tokyo F-Term (reference) within Chemtech Corporation 4H001 CA04 XA05 XA08 XA13 XA38 YA12 YA20 YA25 YA63 YA83

Claims (1)

[Claims] 1. The general formula (SrEu)Al ₂ O ₄ .n[(SrEu)O .(Al _1-ab B _b Q
_a ) ₂ O ₃ (AlO.OH)] [In the formula, Q is at least one selected from Bi, Ca, Mg, and Mn, and a is 0.0005≦a≦0.
002, b is 0.001 ≤ b ≤ 0.35, and n is 1 ≤ n ≤ 7]. material.