JP3560085B2 - Aluminate phosphor - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a divalent europium-activated or divalent europium- and divalent manganese co-activated aluminate phosphor, and more particularly, this phosphor is suitable for a three-wavelength band fluorescent lamp. It is.
[0002]
[Prior art]
In recent years, in the field of fluorescent lamps for general illumination, a three-wavelength band fluorescent lamp has been developed and put to practical use. The phosphor used in this lamp is a mixture of three kinds of phosphors of blue, green and red having a relatively narrow band emission spectrum distribution at an appropriate ratio, and has a high efficiency and a high color rendering property. It has been realized. Also, recently, in addition to these three kinds of phosphors, a blue-green phosphor and a three-wavelength-band emission fluorescent lamp to which a deep red phosphor has been added have been put to practical use.
[0003]
In the three-band fluorescent lamp, when the light output of the phosphors decreases and the emission color changes greatly during lamp operation, the balance between the light output and the emission color between the phosphors is lost, and the color shift phenomenon occurs. Is known to cause
It is also known that baking at 400 ° C. to 800 ° C. is performed one or more times during the manufacture of a fluorescent lamp, and the phosphor deteriorates during this baking to lower the luminous efficiency of the lamp.
[0004]
Aluminate phosphors activated with divalent europium and coactivated with divalent europium and manganese have high luminous efficiency when excited by ultraviolet light (see Japanese Patent Publication No. 52-22836), and emit light in a three-wavelength region. It has often been used as a blue and blue-green emitting phosphor for fluorescent lamps (JOURNAL OF ELECTROCHEMICAL SOCIETY 121 (1974) 1627-1631).
However, a fluorescent lamp using this phosphor as a blue component of a three-wavelength band fluorescent lamp has a disadvantage that the color shift is large. To solve this problem, the composition of the aluminate phosphor is limited to an extremely narrow range (JP-A-3-106987), and a small amount of manganese is added (JP-A-3-106988). However, further improvement is desired.
[0005]
Further, this phosphor also has a drawback that the luminous intensity is greatly reduced due to baking treatment performed during lamp production. It is expected that the solution of this problem will further increase the luminous efficiency of the three-band fluorescent lamp.
Furthermore, as a method of solving the above-mentioned problem of the color shift, it is effective to specify the crystal structure of a divalent europium-activated or divalent europium- and divalent manganese co-activated aluminate phosphor. Was found. One way to obtain the specified crystal structure is to increase the europium concentration. However, increasing the europium concentration causes a problem that the emission intensity is greatly reduced by the baking treatment.
[0006]
Further, at least _{JP-A-6-17049,} was chosen _{(M 1-x-y Eu} x Mn y) O · aAl 2 O 3 · bRE ( wherein, M is Mg, Ca, Sr and Ba It is disclosed that one kind of element, RE represents at least one kind of element selected from Sm and Yb) is an aluminate phosphor which has solved the problem of color shift. It is said that setting to 1 or more is effective. However, our follow-up test confirmed that when b was set to 0.1 or more, impurities different from the aluminate phosphor appeared and a pure phosphor could not be obtained.
[0007]
[Problems to be solved by the invention]
It is an object of the present invention to provide a high-purity divalent europium-activated or divalent europium- and divalent manganese co-activated aluminate phosphor with a small decrease in emission intensity during the baking treatment.
[0008]
[Means for Solving the Problems]
We add Ln (Ln is at least one of Sm, Tm and Yb) to a divalent europium-activated or aluminate phosphor co-activated with divalent europium and divalent manganese. The present inventors have found that deterioration during baking is alleviated, and have reached the present invention. That is, the gist of the present invention is represented by the general formula
^{_{(M 1 1-xy E ux}} L ny) O · a (M 2 1-z M nz) O · bAl 2 O 3
( Wherein , M ¹ represents at least one element selected from the group consisting of Ba, Sr and Ca, M ² represents Mg and / or Zn, and Ln selected from the group consisting of Sm, Tm and Yb. A, b, x, y, and z represent 1 ≦ a ≦ 2, 4.5 ≦ b ≦ 5, 0 <x <1, 0 <y <0.1, 0, respectively. ≦ z <1, (where x represents a real number of x + y <1) .
[0009]
In addition, as a method for evaluating the decrease in the light emission intensity during the baking treatment during lamp production, 5 g of the phosphor was placed in a crucible, and the retention rate of the light emission intensity after baking at 750 ° C. for 10 minutes in air was measured.
Further, since the luminance of the phosphors emitting blue and blue-green light is greatly affected by the visibility, the luminance varies greatly depending on the emission color even at the same luminous efficiency. The value Br / y obtained by dividing Br by the y value of the emission color was used. That is, baking before the luminance and luminous color y values each _Br i, and _{y i,} it _Br b after baking, when _{y b,} baking luminous intensity retention ratio Mb is
[0010]
(Equation 2)
Mb = (Br _b / y _b ) / (Br _i / y _i ) × 100%
[0011]
It becomes. Since the baking emission intensity maintenance ratio Mb varies depending on the activator concentration and the particle size, the effect of the improvement is a numerical value to be evaluated between substances having the same activator concentration and the same flux concentration and the same baking method.
We presume that divalent europium is oxidized by baking in the air and changes to trivalent europium, EuAlO ₃ is generated, and the emission intensity is reduced. The added Ln (Ln is at least one element of Sm, Tm and Yb) exists between the spinel blocks in the crystal of the aluminate phosphor in a divalent form, instead of oxidizing europium during baking. It is presumed that the decrease in the light emission intensity is suppressed by being oxidized.
[0012]
The phosphor of the present invention comprises (a) at least one element selected from the group consisting of Ba, Sr and Ca, and (b) at least one element selected from the group consisting of Eu, (c) Sm, Tm and Yb. There is no particular limitation on the aluminate phosphor characterized by containing the elements, (d) Mg and / or Zn, and (e) Al, and (f) Mn as necessary. Specifically, the general formula:
(Equation 3)
^{_{a (M 1 1-x-}} y Eu x Ln y) O · a (M 2 1-z Mn z) O · bAl 2 O 3
[0014]
(Wherein, M ¹ represents at least one element selected from the group consisting of Ba, Sr and Ca, M ² represents Mg and / or Zn, and Ln is selected from the group consisting of Sm, Tm and Yb. A, b, x, y and z are respectively 1 ≦ a ≦ 2, 4.5 ≦ b ≦ 5, 0 <x <1, 0 <y <1, 0 ≦ z <1 (Where x + y <1 represents a real number). In the above formula, a is is considered generally 1, is believed to 2 variable by the site of the start of M ² in the crystal. Although b is usually considered to be 5, it can be considered that it changes from 4.5 to 5 with the change of a. x is variable from 0 to 1 in terms of crystal structure, but sufficient emission intensity can be obtained from 0.05 to 0.5. The Ln amount y is preferably 0 <y <0.1 because the effect of the present invention was observed at an amount less than 0.1, and the initial light emission intensity tends to decrease when it is 0.1 or more. . Although z is also variable from 0 to 1 in crystal structure, sufficient emission intensity can be obtained at 0.2 or less. Lm is preferably Tm.
[0015]
Even if the blending is out of the specified range, a mixture of the phosphor of the present invention and impurities such as Al ₂ O ₃ , MgAl ₂ O ₄ , and EuAlO ₃ may be obtained, but this departs from the gist of the present invention. Not.
The application of the phosphor of the present invention is effective for an object that is baked in the manufacturing process, and is not limited to a fluorescent lamp. For example, it can be applied to a plasma display.
[0016]
Figure _{1, (Ba 0.8-y Eu 0.2} Ln y) respectively Ln at _{O · MgO · 5Al 2 O 3} , Sm, Tm, baking luminous intensity maintenance of the phosphor prepared in formulated composition was Yb It is a thing which showed rate Mb.
The phosphor of the present invention can be synthesized as follows. As a phosphor material,
[0017]
[Table 1]
(1) barium compounds such as barium oxide, barium hydroxide and barium carbonate (2) strontium compounds such as strontium oxide, strontium hydroxide and strontium carbonate (3) calcium compounds such as calcium oxide, calcium hydroxide and calcium carbonate (4) ) Europium compounds such as europium oxide and europium fluoride (5) Samarium compounds such as samarium oxide, samarium nitrate, samarium chloride, samarium carbonate and samarium fluoride (6) Thulium oxide, thulium nitrate, thulium chloride, thulium carbonate, fluoride Thulium compounds such as thulium (7) ytterbium compounds such as ytterbium oxide, ytterbium nitrate, ytterbium chloride, ytterbium carbonate, ytterbium fluoride (8) magnesium oxide, magnesium hydroxide Magnesium compounds such as magnesium carbonate (9) Zinc compounds such as zinc oxide, zinc hydroxide and zinc carbonate (10) Manganese compounds such as manganese oxide, manganese hydroxide and manganese carbonate (11) Aluminum such as aluminum oxide and aluminum hydroxide Compound [0018]
Is weighed in a predetermined amount, and a flux such as barium fluoride, aluminum fluoride, or magnesium fluoride is blended, and the raw material mixture is sufficiently mixed. The obtained mixture is filled in a crucible and fired at least once in a reducing atmosphere at 1200 to 1700 ° C. for 2 to 40 hours. As a method of obtaining a reducing atmosphere, there are a method of embedding a crucible filled with a raw material in a crucible filled with carbon, and a method of putting a carbon substance such as a lump of graphite or coconut hull into a crucible filled with a raw material. To ensure reduction, these crucibles may be further fired in an atmosphere of nitrogen or nitrogen-hydrogen. Further, these atmospheres may contain water vapor. The fired product is dispersed, washed with water, dried and sieved to obtain the blue or blue-green luminescent aluminate phosphor of the present invention.
[0019]
【Example】
Hereinafter, examples of the present invention will be described.
Example 1
[Table 2]
BaCO ₃ 0.799 mol
Eu ₂ O ₃ 0.1 mol
Sm ₂ O ₃ 0.0005 mol
3MgCO ₃ .Mg (OH) ₂ 0.25 mol
Al ₂ O ₃ (alpha type) 5.0 mol
AlF ₃ 0.010 mol
[0020]
After mixing the above raw materials in a wet manner, drying and sieving, filling the crucible, further placing the crucible containing beaded charcoal on the raw material, covering the raw material at a maximum temperature of 1450 ° C. in a nitrogen atmosphere containing steam. Firing was performed for 11 hours including the temperature rise and fall times. Next, the calcined powder is dispersed, washed, dried, and sieved to obtain a divalent europium-activated blue light-emitting barium (Ba _0.799 Eu _0.2 Sm _0.001 ) O.MgO.5Al ₂ O ₃ barium. A magnesium aluminate phosphor was obtained. The baking emission intensity maintenance ratio Mb of this phosphor was 76.5%.
[0021]
Example 2
[Table 3]
BaCO ₃ 0.79 mol
Eu ₂ O ₃ 0.1 mol
Sm ₂ O ₃ 0.005 mol
3MgCO ₃ .Mg (OH) ₂ 0.25 mol
Al ₂ O ₃ (alpha type) 5.0 mol
AlF ₃ 0.010 mol
[0022]
The above-mentioned raw material is subjected to the same treatment as in Example 1 to give a divalent europium-activated blue-emitting barium magnesium aluminate fluorescent material of (Ba _0.79 Eu _0.2 Sm _0.01 ) O.MgO.5Al ₂ O _3. Got a body. The baking emission intensity maintenance ratio Mb of this phosphor was 80.0%.
[0023]
Example 3
[Table 4]
BaCO ₃ 0.799 mol
Eu ₂ O ₃ 0.1 mol
Tm ₂ O ₃ 0.0005 mol
3MgCO ₃ .Mg (OH) ₂ 0.25 mol
Al ₂ O ₃ (alpha type) 5.0 mol
AlF ₃ 0.010 mol
[0024]
The above-mentioned raw material was subjected to the same treatment as in Example 1 to obtain a divalent europium-activated blue-emitting barium magnesium aluminate fluorescent material of (Ba _0.799 Eu _0.2 Tm _0.001 ) O.MgO.5Al ₂ O _3. Got a body. The baking emission intensity maintenance ratio Mb of this phosphor was 83.9%.
[0025]
Example 4
[Table 5]
BaCO ₃ 0.79 mol
Eu ₂ O ₃ 0.1 mol
Tm ₂ O ₃ 0.005 mol
3MgCO ₃ .Mg (OH) ₂ 0.25 mol
Al ₂ O ₃ (alpha type) 5.0 mol
AlF ₃ 0.010 mol
[0026]
The above-mentioned raw material is subjected to the same treatment as in Example 1 to obtain a divalent europium-activated blue-emitting barium magnesium aluminate fluorescent material of (Ba _0.79 Eu _0.2 Tm _0.01 ) O.MgO.5Al ₂ O _3. Got a body. The baking emission intensity maintenance ratio Mb of this phosphor was 89.1%.
[0027]
Example 5
[Table 6]
BaCO ₃ 0.79 mol
Eu ₂ O ₃ 0.1 mol
Yb ₂ O ₃ 0.005 mol
3MgCO ₃ .Mg (OH) ₂ 0.25 mol
Al ₂ O ₃ (alpha type) 5.0 mol
AlF ₃ 0.010 mol
[0028]
The above-mentioned raw material was subjected to the same treatment as in Example 1 to obtain a divalent europium-activated blue-emitting barium magnesium aluminate fluorescent material of (Ba _0.79 Eu _0.2 Yb _0.01 ) O.MgO.5Al ₂ O _3. Got a body. The baking emission intensity maintenance ratio Mb of this phosphor was 82.2%.
[0029]
Comparative Example 1
[Table 7]
BaCO ₃ 0.8 mol
Eu ₂ O ₃ 0.1 mol
3MgCO ₃ .Mg (OH) ₂ 0.25 mol
Al ₂ O ₃ (alpha type) 5.0 mol
AlF ₃ 0.010 mol
[0030]
The above-mentioned raw material was subjected to the same treatment as in Example 1 to obtain a divalent europium-activated blue-emitting barium magnesium aluminate phosphor of (Ba _0.8 Eu _0.2 ) O.MgO.5Al ₂ O ₃ . . The baking emission intensity maintenance ratio Mb of this phosphor was 74.8%.
Comparative Example 1 and Examples 1, 2, 3, 4, and 5 are all the same except for the inclusion of Ln (Ln is at least one of Sm, Tm, and Yb). Improvements are noted.
[0031]
Example 6
[Table 8]
BaCO ₃ 0.895 mol
Eu ₂ O ₃ 0.05 mol
Tm ₂ O ₃ 0.0025 mol
3MgCO ₃ .Mg (OH) ₂ 0.25 mol
Al ₂ O ₃ (alpha type) 5.0 mol
AlF ₃ 0.012 mol
[0032]
After mixing the above raw materials in a wet manner, drying and sieving, filling the crucible, further placing the crucible containing beaded charcoal on the raw material, covering the raw material at a maximum temperature of 1450 ° C. in a nitrogen atmosphere containing steam. The primary firing was performed for 11 hours including the temperature rise / fall time. Next, the calcined powder is pulverized, sieved, filled into the crucible again, placed on a crucible containing beaded charcoal, and covered with a nitrogen-hydrogen mixed atmosphere containing steam at a maximum temperature of 1450 ° C. The secondary firing was performed for 11 hours. Next, the calcined powder is dispersed, washed, dried and sieved to obtain a divalent europium-activated blue light-emitting barium (Ba _0.895 Eu _0.1 Tm _0.005 ) O.MgO.5Al ₂ O _3. A magnesium aluminate phosphor was obtained. The baking emission intensity maintenance ratio Mb of this phosphor was 76.8%.
[0033]
Example 7
[Table 9]
BaCO ₃ 0.895 mol
Eu ₂ O ₃ 0.05 mol
Yb ₂ O ₃ 0.0025 mol
3MgCO ₃ .Mg (OH) ₂ 0.25 mol
Al ₂ O ₃ (gamma type) 5.0 mol
AlF ₃ 0.012 mol
[0034]
The above-mentioned raw material is subjected to the same treatment as in Example 6 to obtain a divalent europium-activated blue-emitting barium magnesium aluminate fluorescent material of (Ba _0.895 Eu _0.1 Yb _0.005 ) O.MgO.5Al ₂ O _3. Got a body. The baking emission intensity maintenance ratio Mb of this phosphor was 77.7%.
[0035]
Comparative Example 2
[Table 10]
BaCO ₃ 0.9 mol
Eu ₂ O ₃ 0.05 mol
3MgCO ₃ .Mg (OH) ₂ 0.25 mol
Al ₂ O ₃ (gamma type) 5.0 mol
AlF ₃ 0.012 mol
[0036]
The same treatment as in Example 6 was performed on the above raw material to obtain a divalent europium-activated blue-emitting barium magnesium aluminate phosphor of (Ba _0.9 Eu _0.1 ) O.MgO.5Al ₂ O ₃ . . The baking emission intensity maintenance ratio Mb of this phosphor was 74.5%.
Comparative Example 2, Examples 6 and 7 are all the same except for the inclusion of Ln (Ln is at least one element of Sm, Tm and Yb), and the improvement of the baking emission intensity maintenance rate by the inclusion of Ln is recognized. .
[0037]
Example 8
[Table 11]
BaCO ₃ 0.79 mol
Eu ₂ O ₃ 0.1 mol
Sm ₂ O ₃ 0.005 mol
MgO 0.98 mol
MnO ₂ 0.02 mol
Al ₂ O ₃ (gamma type) 5.0 mol
AlF ₃ 0.01 mol
[0038]
Subjected to the same treatment as in Example 1 to the raw _{material, (Ba 0. 7 9 Eu 0.} 2 Sm _{0.0 1)} was obtained _{O · (Mg 0.98 Mn 0.02)} 2 divalent europium-activated blue-emitting barium magnesium manganese aluminate phosphor _O · _5Al 2 O _3. The baking emission intensity maintenance ratio Mb of this phosphor was 75.3%.
[0039]
Comparative Example 3
[Table 12]
BaCO ₃ 0.8 mol
Eu ₂ O ₃ 0.1 mol
MgO 0.98 mol
MnO ₂ 0.02 mol
Al ₂ O ₃ (gamma type) 5.0 mol
AlF ₃ 0.01 mol
[0040]
Subjected to the same treatment as in Example 1 to the raw material, _{(Ba 0. 8} Eu _{0. 2} ) A bivalent europium-activated blue-emitting barium magnesium manganese aluminate phosphor of O · (Mg _0.98 Mn _0.02 ) O · 5Al ₂ O ₃ was obtained. The baking emission intensity maintenance ratio Mb of this phosphor was 70.5%.
Example 8 and Comparative Example 3 are all the same except for the inclusion of Ln (Ln is at least one element of Sm, Tm, and Yb), and the improvement of the baking emission intensity maintenance rate by the inclusion of Ln is recognized.
[0041]
Example 9
[Table 13]
BaCO ₃ 0.59 mol
SrCO ₃ 0.3 mol
Eu ₂ O ₃ 0.05 mol
Tm ₂ O ₃ 0.005 mol
MgO 0.98 mol
MnO ₂ 0.02 mol
Al ₂ O ₃ (gamma type) 5.0 mol
AlF ₃ 0.01 mol
[0042]
Subjected to the same treatment as in Example 1 to the raw _{material, (Ba 0. 5 9 Sr 0.3} Eu 0. 1 Tm _{0.0 1)} was obtained _{O · (Mg 0.98 Mn 0.02)} 2 divalent europium-activated blue-emitting barium magnesium manganese aluminate phosphor _O · _5Al 2 O _3. The baking emission intensity maintenance ratio Mb of this phosphor was 84.3%.
[0043]
Comparative Example 4
[Table 14]
BaCO ₃ 0.6 mol
SrCO ₃ 0.3 mol
Eu ₂ O ₃ 0.05 mol
MgO 0.98 mol
MnO ₂ 0.02 mol
Al ₂ O ₃ (gamma type) 5.0 mol
AlF ₃ 0.01 mol
[0044]
Subjected to the same treatment as in Example 1 to the raw material, _{(Ba 0. 6} Sr _0.3 Eu _{0. 1} ) A bivalent europium-activated blue-emitting barium magnesium manganese aluminate phosphor of O · (Mg _0.98 Mn _0.02 ) O · 5Al ₂ O ₃ was obtained. The baking emission intensity maintenance ratio Mb of this phosphor was 82.0%.
Example 9 and Comparative Example 4 are all the same except for the inclusion of Ln (Ln is at least one element of Sm, Tm, and Yb), and the improvement of the baking emission intensity maintenance rate by the inclusion of Ln is recognized.
[0045]
【The invention's effect】
According to the present invention, it is possible to obtain a blue and blue-green light-emitting phosphor with a small decrease in light emission intensity due to baking, and to provide a good fluorescent lamp without a color shift phenomenon.
[Brief description of the drawings]
FIG. 1 shows an example of the relationship between the content y of Ln (Ln is at least one element of Sm, Tm, and Yb) in a phosphor of the present invention and a baking emission intensity maintenance ratio Mb.

Claims (4)

Formula ^{_{(M 1 1-xy E ux}} L ny) O · a (M 2 1-z M nz) O · bAl 2 O 3
(Wherein, M1 is Ba, represents at least one element selected from the group consisting of Sr and Ca, M ² represents Mg and / or Zn, Ln is selected from the group consisting of Sm, Tm and Yb A, b, x, y, and z represent 1 ≦ a ≦ 2, 4.5 ≦ b ≦ 5, 0 <x <1, 0 <y <0.1 , and 0 ≦, respectively. z <1, (provided that x + y <1), wherein a to luer Rumin phosphor that is represented by representing the real) of. The aluminate phosphor according to claim 1, wherein Ln represents Tm or at least one element selected from the group consisting of Tm and Sm and Yb. M ^Two Represents Mg or Mg and Zn, the aluminate phosphor according to claim 1 or 2, wherein x is 0.05 ≦ x ≦ 0.5, aluminate phosphor according to any one of claims 1, characterized in that z is 0 ≦ z ≦ 0.2 3.

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