JP3941471B2 - Method for producing aluminate phosphor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an aluminate phosphor. In particular, the present invention relates to an aluminate phosphor suitable for a vacuum ultraviolet light-excited light emitting device such as a plasma display panel (hereinafter referred to as “PDP”) and a rare gas lamp.
[0002]
[Prior art]
Aluminate phosphors are used in vacuum ultraviolet-excited light emitting elements such as PDPs and rare gas lamps, fluorescent lamps, and phosphorescents for night-light display objects.
For example, Japanese Patent Application Laid-Open No. 8-115673 discloses a single-phase aluminate phosphor BaMgAl ₁₀ O ₁₇ : Eu, and this aluminate phosphor makes ultraviolet light generated by discharge in mercury vapor visible light. Because it converts, it is used for fluorescent lamps. BaMgAl ₁₀ O ₁₇ : Eu is also excited by vacuum ultraviolet light, which is ultraviolet light having a short wavelength of 200 nm or less, and is also used for vacuum ultraviolet light-excited light emitting devices such as PDPs and rare gas lamps. However, the manufacturing process of vacuum ultraviolet light-excited light emitting elements such as PDP and rare gas lamps, fluorescent lamps, and night-light displays may include a process of heating in an oxidizing atmosphere such as air. The aluminate phosphor made of BaMgAl ₁₀ O ₁₇ : Eu has a problem that the luminance is lowered by the heating process and does not show high luminance.
[0003]
[Problems to be solved by the invention]
The objective of this invention is providing the aluminate fluorescent substance which shows a high brightness | luminance after heating in oxidizing atmospheres, such as air, and its manufacturing method.
[0004]
[Means for Solving the Problems]
Under such circumstances, the present inventors have made extensive studies on the aluminate phosphor BaMgAl ₁₀ O ₁₇ : Eu in order to solve the above problems. As a result, when the X-ray diffraction of the aluminate phosphor is measured, Peaks identified in the same crystal structure as BaMgAl ₁₀ O ₁₇ (wherein part of Ba can be replaced by Ca and / or Sr, and part of Ba is replaced by activator Eu) In addition, the same crystal structure as that of BaAl ₂ O ₄ (however, part of Ba can be replaced by Ca and / or Sr, and part of Ba is replaced by Eu as an activator) It has been found that the aluminate phosphor may exhibit high brightness when detected peaks are detected. And although the reason is not clear, there is a relationship between the peak size identified in the same crystal structure as the BaAl ₂ O ₄ and the brightness of the aluminate phosphor after heating in an oxidizing atmosphere such as air, as an indicator of the magnitude of the peaks identified in BaAl ₂ O ₄ of BaMgAl ₁₀ O ₁₇ (114) peak is identified surface integrated intensity S ₀ and BaAl of ₂ O ₄ (202) of the peak identified on surface When the intensity ratio S / S ₀ of the integrated intensity S is selected, if the S / S ₀ is in the range of 0.01 or more and 0.3 or less, the aluminate phosphor will remain after being heated in an oxidizing atmosphere such as air. It was found to show high brightness.
Furthermore, the present inventors have also intensively studied a method for producing the aluminate phosphor, using barium compounds, calcium compounds, strontium compounds, magnesium compounds, europium compounds and aluminum compounds as raw materials, and these raw materials have a predetermined composition. In the method for producing an aluminate phosphor that is blended and fired so that the ratio of metal elements is as _follows , the ratio of the metal element is the composition formula (Ba _1-a M ¹ _a ) _bc Eu _c MgAl ₁₀ O ₁₇ (where M ¹ is Ca And / or Sr, a is 0 or more and 0.5 or less, b is 1.03 or more and 1.13 or less, and c is 0.01 or more and 0.3 or less.) , Calcium compound, strontium compound, europium compound, magnesium compound and aluminum compound, It found that phosphors can be obtained, and have completed the present invention.
[0005]
That is, according to the present invention, in the measurement result of X-ray diffraction, the integrated intensity S _{0 of the} peak identified on the (114) plane of the same crystal structure as BaMgAl ₁₀ O ₁₇ and (202) of the same crystal structure as BaAl ₂ O ₄ are obtained. Provided is an aluminate phosphor exhibiting a peak having an intensity ratio S / S ₀ with an integrated intensity S of a peak identified on a surface of 0.01 or more and 0.3 or less. The present invention also provides a vacuum ultraviolet light-excited light emitting device using the aluminate phosphor described above. Further, in the present invention, the ratio of the metal element is such that the composition formula (Ba _1-a M ¹ _a ) _bc Eu _c MgAl ₁₀ O ₁₇ (where M ¹ is Ca and / or Sr, and a is 0 or more and 0.5 In the following, b is 1.03 or more and 1.13 or less, and c is 0.01 or more and 0.3 or less.) Barium compound, calcium compound, strontium compound, europium compound, magnesium compound and aluminum Provided is a method for producing the aluminate phosphor, which comprises compounding and firing.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below.
The phosphor of the present invention has an integrated intensity S _{0 of} a peak identified on the (114) plane of the same crystal structure as that of BaMgAl ₁₀ O ₁₇ in the measurement result of X-ray diffraction and a crystal structure of the same as that of BaAl ₂ O ₄ ( 202) An aluminate phosphor having an intensity ratio S / S ₀ with respect to an integrated intensity S of a peak identified on the surface of 0.01 to 0.3. When the value of S / S ₀ is smaller than 0.01 or larger than 0.3, high luminance may not be exhibited after heating in an oxidizing atmosphere such as air.
In the phosphor of the present invention, a peak identified in the same crystal structure as BaMgAl ₁₀ O ₁₇ and a peak identified in the same crystal structure as BaAl ₂ O ₄ are detected by X-ray diffraction, so that the same as BaMgAl ₁₀ O ₁₇ is detected. A compound having a crystal structure and a compound having the same crystal structure as BaAl ₂ O ₄ are included. Examples of the compound having the same crystal structure as BaMgAl ₁₀ O _17, a compound Ba is Eu is activated to a compound which may be substituted by Ca and / or Sr of BaMgAl ₁₀ O _17, formula Ba _1-de A compound represented by M ² _d Eu _e MgAl ₁₀ O ₁₇ (where M ² is Ca and / or Sr) and d is 0 or more and 0.5 or less and e is 0.01 or more and 0.3 or less is preferable. Furthermore, BaAl Examples of the compound having the same crystal structure as ₂ O _4, a Ba is Ca and / or Eu may compound be activated to compounds substituted by Sr of BaAl ₂ O _4, the composition formula Ba _{1 -fg} M ³ _f Eu _g Al ₂ O ₄ (wherein M ³ is Ca and / or Sr), and f is 0 or more and 0.5 or less, and g is 0.01 or more and 0.3 or less. preferable.
[0007]
The phosphor of the present invention is particularly suitable for a vacuum ultraviolet light-excited light emitting element because it exhibits a high-luminance blue light emission when excited by vacuum ultraviolet light and exhibits a high luminance by vacuum ultraviolet light excitation even after heating in an oxidizing atmosphere such as air. .
[0008]
The method for producing the phosphor of the present invention is not particularly limited. Generally, barium compounds, calcium compounds, strontium compounds, magnesium compounds, europium compounds, and aluminum compounds are used as raw materials, and these raw materials are used in a predetermined composition. It can manufacture by mix | blending so that it may become, and baking.
[0009]
However, the integrated intensity ratio S / S ₀ of the peak in X-ray diffraction and the abundance ratio of (compound having the same crystal structure as BaAl ₂ O ₄ ) / (compound having the same crystal structure as BaMgAl ₁₀ O ₁₇ ) are not necessarily Since the composition of the powders obtained by evaporation of Ba and Mg during firing does not match, and the composition of the obtained powder may be different, calculate the blending ratio of raw materials from the target S / S ₀ value. It is difficult. Therefore, as a result of the study by the present inventors, the ratio of the metal element is such that the composition formula (Ba _1-a M ¹ _a ) _bc Eu _c MgAl ₁₀ O ₁₇ (where M ¹ is Ca and / or Sr, and a is 0 to 0.5, b is 1.03 to 1.13, and c is 0.01 to 0.3.) Barium compound, calcium compound, strontium compound, europium compound When the magnesium compound and the aluminum compound are blended, the aluminate phosphor of the present invention is obtained.
[0010]
When a is greater than 0.5, b is less than 1.03 or greater than 1.13, or c is less than 0.01 or greater than 0.3, firing in an oxidizing atmosphere such as air After that, high brightness may not be obtained.
[0011]
In the production method of the present invention, high purity (purity: 99.9% or higher) alumina (crystal form may be α alumina or transition alumina), high purity (purity: 99% or higher) water Aluminum oxide, aluminum nitrate, aluminum halide, or the like can be used.
[0012]
The raw material used as the barium source is high purity (99% or higher purity) barium hydroxide, barium carbonate, barium nitrate, barium halide, barium oxalate, etc., which can be decomposed into barium oxide at high temperature or high purity. Barium oxide (purity 99% or more) can be used.
[0013]
The raw material used as a calcium source is high purity (purity 99% or more) calcium hydroxide, calcium carbonate, calcium nitrate, calcium halide, calcium oxalate, etc., which can decompose at high temperatures to become calcium oxide or high purity. Calcium oxide (purity 99% or more) can be used.
[0014]
The raw material used as the source of strontium is high purity (99% or more purity) strontium hydroxide, carbonate, strontium nitrate, strontium halide, strontium oxalate, etc. Strontium oxide (purity 99% or more) can be used.
[0015]
As a raw material to be a magnesium source, high purity (purity 99% or more) magnesium hydroxide, magnesium carbonate, magnesium nitrate, magnesium halide, magnesium oxalate, basic magnesium carbonate, etc. can be decomposed at high temperature to become magnesium oxide. A magnesium oxide having a high purity (purity 99% or more) can be used.
[0016]
The raw materials that can be used as a source of europium include high-purity (99% or higher purity) europium hydroxide, europium carbonate, europium nitrate, europium halide, europium oxalate, etc. that can be decomposed into high-purity (purity) 99% or more) of europium oxide can be used.
[0017]
The raw materials are weighed so as to have a predetermined composition and mixed by a device generally used industrially such as a ball mill, a V-type mixer or a stirring device, and then in a temperature range of 900 ° C. to 1600 ° C. for 1 hour to 50 hours. The phosphor of the present invention can be obtained by the method of holding and firing.
[0018]
The firing atmosphere at this time is preferably a weakly reducing atmosphere having a composition in which 0.1 to 10% by volume of hydrogen is contained in an inert gas such as nitrogen or argon in order to make Eu bivalent. In addition, after firing in an air atmosphere, firing can be performed again in a weakly reducing atmosphere. Moreover, in order to accelerate | stimulate reaction, a flux can also be added. In order to increase the crystallinity of the phosphor, it can be fired again as necessary. In addition, when materials that can be decomposed into oxides at high temperatures such as hydroxide, carbonate, nitrate, halide, oxalate, etc. are used as raw materials in the temperature range of 600 ° C. or more and 800 ° C. or less before the main firing. Pre-baking can be performed to make part or all of the oxide.
[0019]
The phosphor powder obtained by the above method can be pulverized using an industrially used apparatus such as a ball mill, a vibration mill, or a jet mill. Further, it can be washed or classified as required.
[0020]
The aluminate phosphor of the present invention exhibits high luminance when excited by vacuum ultraviolet light, and further exhibits high luminance by vacuum ultraviolet light excitation even after heating in an oxidizing atmosphere, so that it is particularly excited by vacuum ultraviolet light such as PDP and rare gas lamps. Suitable for light-emitting elements.
[0021]
A PDP using the phosphor of the present invention can be produced by a known method as disclosed in, for example, JP-A-10-195428. Blue, green, and red phosphors for vacuum ultraviolet light-excited light emitting devices are mixed with, for example, a binder made of a polymer compound such as a cellulose compound and polyvinyl alcohol, and an organic solvent to prepare a phosphor paste. The paste is applied to the linear substrate surface and the partition surface of the inner surface of the back substrate, which are partitioned by partition walls, and provided with address electrodes, by a method such as screen printing, and baked at a temperature of about 500 ° C. It is removed by incineration to form each phosphor layer. This is provided with a transparent electrode and a bus electrode in a direction orthogonal to the phosphor layer, and a surface glass substrate provided with a dielectric layer and a protective layer on the inner surface is laminated and bonded, and the inside is evacuated to low pressure Xe, Ne, etc. PDP can be manufactured by enclosing a rare gas and forming a large number of discharge spaces. The rare gas lamp has the same structure as the PDP when the number of discharge spaces is small and the number of phosphor colors is small in some cases, and can be manufactured in the same manner as described above. Vacuum ultraviolet-excited light emitting devices such as PDPs and rare gas lamps using the phosphor of the present invention show high luminance because the blue phosphor exhibits high luminance even after heating in an oxidizing atmosphere such as air in the manufacturing process. .
[0022]
The phosphor of the present invention can be excited by ultraviolet rays other than the vacuum ultraviolet region, X-rays, and electron beams, and is also used for an element using ultraviolet rays, X-rays, and electron beams other than the vacuum ultraviolet region as excitation sources. Can do.
[0023]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.
In addition, the integrated intensity | strength of the peak of the X-ray diffraction pattern of each sample was calculated | required as follows. The RADII-C type manufactured by Rigaku is used as the X-ray diffraction measurement apparatus, the X-ray source: CuKα, tube voltage 50 kV, tube current 30 mA, divergence slit (DS) = 1 °, scattering slit (SS) = 1 °, light reception Slit (RS) = 0.3 mm, scanning speed 0.1 ° / min, scanning step = 0.02 °, a specific angle is set by the peak of the measurement angle range, and the range from the low angle side θa to the high angle side θb Went in. Specifically, θa = 27.9 ° and θb = 28.9 ° in the (202) plane of BaAl ₂ O ₄ , and θa = 35.1 °, θb = 36.1 in the (114) plane of BaMgAl ₁₀ O _17. Was done as °. Since an integrated value proportional to the area of the peak is obtained, the background is subtracted from each to obtain the peak integrated intensity. In the obtained X-ray diffraction chart, the portion below the straight line connecting the two points corresponding to the angles θa and θb was defined as the background.
[0024]
Comparative Example 1
Aluminum hydroxide, barium carbonate, basic magnesium carbonate pentahydrate and europium oxide in a molar ratio of Al: Ba: Mg: Eu = 10.00: 0.855: 1.00: 0.10 That weighed so as to have the same ratio as the composition formula _{Ba 0.955-0.10 Eu 0.10 MgAl 10 O 17} , and mixed for 4 hours by a ball mill to obtain a mixed powder. The obtained mixed powder was put into an alumina boat, fired by holding at 1450 ° C. for 2 hours in a reducing atmosphere composed of 98% by volume of argon and 2% by volume of hydrogen, and then gradually cooled to room temperature to obtain a powder ( Sample C). The obtained powder was thermally deteriorated at 500 ° C. in an air atmosphere. The heat-degraded powder is placed in a vacuum chamber, kept at a vacuum of 6.7 Pa (5 × 10 ⁻² torr) or less, and irradiated with ultraviolet rays using an excimer 146 nm lamp (H0012 type manufactured by USHIO INC.). As a result, blue light was emitted. The luminance of Sample C of Comparative Example 1 was set as 100, which was used as a luminance reference in the following Examples and Comparative Examples.
[0025]
Sample C is subjected to X-ray diffraction measurement. Among the peaks identified as BaMgAl ₁₀ O ₁₇ , the peak integrated intensity S ₀ of the (114) plane and the peak identified as BaAl ₂ O ₄ (202) The intensity ratio S / S ₀ with respect to the peak integrated intensity S of the surface was found to be 0.000.
[0026]
Example 1
Aluminum hydroxide, barium carbonate, basic magnesium carbonate pentahydrate and europium oxide in a molar ratio of Al: Ba: Mg: Eu = 10.00: 0.945: 1.00: 0.10, The composition formula Ba _1.045-0.10 Eu _0.10 MgAl ₁₀ O ₁₇ was weighed so as to have the same ratio and stirred and mixed with a ball mill for 4 hours, and then the mixed powder was recovered. The obtained mixed powder was baked on an alumina boat in a reducing atmosphere of a mixed gas of argon and hydrogen (containing 2% by volume of hydrogen) at 1450 ° C. for 2 hours, and then gradually cooled to room temperature. A powder (Sample 1) was obtained.
Sample 1 was thermally deteriorated at 500 ° C. in an air atmosphere. The heat-degraded powder is placed in a vacuum chamber, kept at a vacuum of 6.7 Pa (5 × 10 ⁻² torr) or less, and irradiated with ultraviolet rays using an excimer 146 nm lamp (H0012 type manufactured by USHIO INC.). As a result, blue light was emitted, and the luminance when the luminance of Sample C of Comparative Example 1 was 100 was 121.6.
[0027]
Sample 1 is subjected to X-ray diffraction measurement, and the peak integrated intensity S ₀ of the (114) plane among the peaks identified for BaMgAl ₁₀ O ₁₇ and the (202) plane of the peaks identified for BaAl ₂ O ₄ The intensity ratio S / S ₀ with respect to the peak integrated intensity S was 0.024.
[0028]
Example 2
Example except that the molar ratio was Al: Ba: Mg: Eu = 10: 0.99: 1.00: 0.10, that is, the same ratio as the composition formula Ba _1.09-0.10 Eu _0.10 MgAl ₁₀ O ₁₇ In the same manner as in Example 1, a powder (Sample 2) was obtained. Sample 2 was thermally degraded at 500 ° C. in an air atmosphere. The heat-degraded powder is placed in a vacuum chamber, kept at a vacuum of 6.7 Pa (5 × 10 ⁻² torr) or less, and irradiated with ultraviolet rays using an excimer 146 nm lamp (H0012 type manufactured by USHIO INC.). As a result, blue light was emitted, and the luminance was 120.6, assuming that the luminance of Sample C of Comparative Example 1 was 100.
[0029]
Sample 2 before heating at 500 ° C. is subjected to X-ray diffraction measurement. Among the peaks identified as BaMgAl ₁₀ O ₁₇ , the peak integrated intensity S ₀ of the (114) plane and the peak identified as BaAl ₂ O ₄ Of these, the intensity ratio S / S ₀ with respect to the peak integrated intensity S of the (202) plane was found to be 0.211.
[0030]
Comparative Example 2
_Except that the molar ratio was Al: Ba: Mg: Eu = 10.00: 1.04: 1.00: 0.10, that is, the same ratio as the composition formula Ba _1.14-0.10 Eu _0.10 MgAl ₁₀ O ₁₇ A powder (sample D) was obtained in the same manner as in Example 1. Sample D was heated at 500 ° C. in an air atmosphere. The heated powder was placed in a vacuum chamber, kept at a vacuum of 6.7 Pa (5 × 10 ⁻² torr) or less, and irradiated with vacuum ultraviolet rays using an excimer 146 nm lamp (H0012 type manufactured by USHIO INC.). However, blue light was emitted and the luminance was 105.6.
[0031]
Sample D is subjected to X-ray diffraction measurement, and the peak integrated intensity S ₀ of the (114) plane among the peaks identified for BaMgAl ₁₀ O ₁₇ and (202) of the peaks identified for BaAl ₂ O ₄ The intensity ratio S / S ₀ with the peak integrated intensity S of the surface was 0.319.
[0032]
【The invention's effect】
The aluminate phosphor of the present invention exhibits high luminance even after heating in an oxidizing atmosphere, and particularly exhibits high luminance due to vacuum ultraviolet excitation, and thus is suitable for vacuum ultraviolet excitation light emitting devices such as PDPs and rare gas lamps. Since a vacuum ultraviolet ray excitation light emitting device having high emission luminance can be realized, it is extremely useful industrially.

Claims (3)

In the measurement result of X-ray diffraction, the integrated intensity S _{0 of the} peak identified on the (114) plane of the same crystal structure as that of BaMgAl ₁₀ O ₁₇ and the (202) plane of the same crystal structure as that of BaAl ₂ O ₄ are identified. A method for producing an aluminate phosphor, wherein the intensity ratio S / S ₀ with respect to the integrated intensity S of the peak is 0.01 or more and 0.3 or less, wherein the ratio of the metal element is , Composition formula (Ba _1-a M ¹ _a ) _bc Eu _c MgAl ₁₀ O ₁₇ (where M ¹ is Ca and / or Sr, a is 0 or more and 0.5 or less, b is 1.03 or more and 1. 13 or less, c is Ri der 0.01 to 0.3, barium such that the same ratio as unless it is _{(Ba 0.8949 Ca 0.0001 Sr 0.005 Eu} 0.2) O · MgO · 5Al 2 O 3.) Compound, calcium compound, strontium compound, europium A method for producing an aluminate phosphor, comprising mixing a compound, a magnesium compound, and an aluminum compound and firing.   The manufacturing method according to claim 1, wherein the firing temperature is in a temperature range of 900 ° C or higher and 1600 ° C or lower.   The manufacturing method according to claim 1 or 2, wherein the aluminate phosphor is an aluminate phosphor for a vacuum ultraviolet ray-excited light emitting device.