JP2002080843A - Light-emitting fluorescent substance by vacuum ultraviolet radiation excitation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorescent substance which is used in a plasma display panel, a high load fluorescent lamp, a rare gas discharge lamp or the like, particularly a light-emitting fluorescent substance by vacuum ultraviolet radiation excitation which has a good brightness maintenance factor in a device. SOLUTION: The light-emitting fluorescent substance by vacuum ultraviolet radiation excitation has 0.5-100 pts.wt., based on 100 pts.wt. first fluorescent substance, second fluorescent substance which has a specific surface area of 3-50 m2/g and has been coated on the particle surface of the first fluorescent substance, and the above first fluorescent substance is excited by vacuum ultraviolet radiation to emit light in the visible region and the above second fluorescent substance is excited by vacuum ultraviolet radiation to have an emission peak wavelength in the wavelength region of 200-450 nm and, simultaneously, the above first fluorescent substance is also excited by the light radiated by the above second fluorescent substance to emit light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phosphor used for a plasma display panel, a high-load fluorescent lamp, a rare gas discharge lamp, and the like. About the body.

[0002]

2. Description of the Related Art A color plasma display panel (hereinafter referred to as a PDP) or a fluorescent lamp excites a phosphor to a high energy state by ultraviolet radiation energy generated in a discharge space, and a wavelength conversion generated at the time of transition to a low energy state. This is a light emitting device that takes out the emitted energy as fluorescence and uses it. Conventionally, vacuum ultraviolet light used in such a light emitting device has a problem that since the photon energy is large, lattice defects or the like are generated in the phosphor, and the emission luminance of the phosphor is greatly reduced with time. For example, (H12 Illuminating Engineering Institute MD-00-22B
It is reported that the emission luminance of the BAM-based phosphor is reduced by vacuum ultraviolet rays emitted from Xe which is an excitation source such as a PDP or a Xe excitation lamp. In contrast, the present applicant has disclosed in Japanese Patent Application Laid-Open No. 10-298.
548, in JP-A 10-330746 has disclosed that the aging of the luminance is suppressed by coating the _{B 2 O 3, Sb 2 O} 3 or the like to a BAM phosphor. In this case, there is a problem that if the coating amount is small, the effect is small, and if the coating amount is large, the luminance is significantly reduced. Also, JP-A-11-6
7103 includes a BAM phosphor (BaMgAl ₁₀ O ₁₇ : E).
u) is mixed with a phosphor (LaPO ₄ : Ce) that converts vacuum ultraviolet light into ultraviolet light having a longer wavelength than the vacuum ultraviolet light, and describes that PDP obtained by coating is capable of suppressing deterioration of luminance over time. ing. However, in this case, since the vacuum ultraviolet rays are also directly irradiated to the BAM phosphor, the effect of suppressing the temporal deterioration of the luminance was small.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to suppress the deterioration of the luminance of a phosphor with time due to vacuum ultraviolet rays.

[0004]

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that the surface of the particles of the first phosphor, which emits light when excited by vacuum ultraviolet light and ultraviolet to blue light, is exposed to vacuum ultraviolet light. The inventors have found that the above problems can be solved by coating the second phosphor, which is a fine particle that emits ultraviolet to blue light when excited, and have completed the present invention.

[0005] The vacuum ultraviolet ray excited light emitting phosphor according to claim 1 of the present invention has a specific surface area of 3 on the particle surface of the first phosphor.
A VUV-excited luminescent phosphor coated with 0.5 to 100 parts by weight of a second phosphor of 〜50 m ² / g per 100 parts by weight of the first phosphor, wherein the first phosphor is a vacuum ultraviolet ray A phosphor that is excited and emits light in the visible region, wherein the second phosphor is a phosphor that is excited by vacuum ultraviolet light and has an emission peak wavelength in a wavelength region of 200 to 450 nm, and the first phosphor is the second phosphor It is characterized in that light emitted from the phosphor is excited and emits light.

According to a second aspect of the present invention, in the vacuum ultraviolet ray excited light emitting phosphor, the first phosphor is BaMgAl ₁₀ O ₁₇ :
Eu, BaMgAl ₁₀ O ₁₇ : Eu, Mn, BaAl ₁₂ O
₁₉ : Mn, SrAl ₂ O ₄ : Eu, Sr ₄ Al ₁₄ O ₂₅ : E
u, Y ₂ O ₃ : Eu, and at least one selected from the group consisting of (Y, Gd) ₂ O ₃ : Eu.

According to a third aspect of the present invention, in the vacuum ultraviolet ray excited light emitting phosphor, the second phosphor is BaSi ₂ O ₅ : Pb,
(Ba, Sr, Mg) ₃ Si ₂ O ₇ : Pb, SrB ₄ O ₇ :
Eu, (Ca, Zn) ₃ (PO ₄ ) ₂ : Tl, Ca ₃ (PO
₄ ) ₂ : Tl, YPO ₄ : Ce, LaPO ₄ : Ce, Y
(P, V) O ₄ , Y ₂ SiO ₅ : Ce, CaWO ₄ , CaW
O ₄ : at least one selected from the group consisting of Pb.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The first phosphor used in the VUV-excited luminescent phosphor of the present invention is BaMgAl ₁₀ O.
₁₇ : Eu, BaMgAl ₁₀ O ₁₇ : Eu, Mn, BaAl
₁₂ O ₁₉ : Mn, SrAl ₂ O ₄ : Eu, Sr ₄ Al
₁₄ O ₂₅ : Eu, Y ₂ O ₃ : Eu, (Y, Gd) ₂ O ₃ : Eu
And the like are preferably used. These phosphors are phosphors that emit light when excited by vacuum ultraviolet light and ultraviolet to blue light, but have a problem in that brightness is reduced by irradiation with vacuum ultraviolet light. Therefore, by coating the second phosphor that emits ultraviolet to blue light when excited by vacuum ultraviolet light, it is possible to suppress deterioration of the luminance of the phosphor with time.

Further, as the second phosphor, BaSi
₂ O ₅ : Pb, (Ba, Sr, Mg) ₃ Si ₂ O ₇ : Pb,
SrB ₄ O ₇ : Eu, (Ca, Zn) ₃ (PO ₄ ) ₂ : T
1, Ca ₃ (PO ₄ ) ₂ : Tl, YPO ₄ : Ce, LaPO
₄ : Ce, Y (P, V) O ₄ , Y ₂ SiO ₅ : Ce, CaW
O ₄ , CaWO ₄ : Pb and the like are preferably used. These phosphors are phosphors that emit ultraviolet to blue light when excited by vacuum ultraviolet rays, but do not decrease in luminance due to irradiation with vacuum ultraviolet rays. Therefore, by coating the surface of the particles of the first phosphor that emits light when excited by vacuum ultraviolet light and ultraviolet to blue light, it is possible to suppress deterioration with time of the luminance of the phosphor.

The specific surface area of the second phosphor is 3 to 50 m ^2.
/ G range. This is because the specific surface area of the second phosphor is 3
In the case of less than m ² / g, the particle size of the second phosphor is large, the coating of the particle surface of the first phosphor becomes insufficient, and a portion where vacuum ultraviolet rays are directly irradiated to the first phosphor is formed. On the other hand, when the luminance exceeds 50 m ² / g, the luminous efficiency of the second phosphor decreases, and the luminous efficiency of the phosphor of the present invention as a whole decreases. Because you do. The coating amount of the second phosphor is preferably in the range of 0.5 to 100 parts by weight based on 100 parts by weight of the first phosphor. This is because the coating amount of the second phosphor is 0.5
If the amount is less than 100 parts by weight, the effect of suppressing the deterioration of the luminance over time is small, and if it exceeds 100 parts by weight, the luminous efficiency of the phosphor of the present invention is reduced.

Next, as a method for coating the first phosphor with the second phosphor, a method based on mechanofusion is preferably used. In this coating method, by rotating a container containing both phosphors at a high speed, both phosphor particles are dispersed in a gas phase, and mechanical energy mainly comprising impact force, contact charging, van der Waals This is a method of coating using electric energy mainly composed of force. As another coating method, both phosphors can be dispersed in water, and coating can be performed by using the cohesive force of the second phosphor, which is a fine particle during pH adjustment and drying.

BaMgAl having an average particle size of 2.0 μm
₁₀ O _17: Eu phosphor on the particle surfaces of the (first phosphor), a specific surface area of 6.1 m ² / g, average particle size 0.8μm of LaPO _4:
In the case of coating with Ce phosphor (second phosphor), L
The solid line is plotted in FIG. 1 for the luminance retention ratio with respect to the coating amount of the aPO ₄ : Ce phosphor. The measurement was performed using an ultraviolet spectrophotometer to measure the relative luminance of the phosphor measurement sample at the time of excitation with vacuum ultraviolet light having a wavelength of 147 nm.
A mixed gas of -Xe-He is set in a glass tube filled with 4 torr, and arc discharge is performed at a current of 1.2 A and a voltage of 130 V for 1 hour, and only vacuum ultraviolet rays are irradiated to forcibly degrade. Then, the forcibly deteriorated sample was measured for relative luminance at the time of excitation with vacuum ultraviolet light having a wavelength of 147 nm, and the percentage of the value obtained by dividing the measured value obtained by the obtained value by the measured value obtained by the above was obtained. I do. From the solid line in the figure, the luminance maintenance ratio is La
It can be seen that the coating amount of the PO ₄ : Ce phosphor is higher at 0.5 parts by weight or more, and further higher at 20 parts by weight or more. The dashed line in the figure indicates BaMgAl ₁₀ as a comparative example.
O ₁₇ : Eu phosphor (first phosphor) and specific surface area 0.45 m
² / g, an average particle size of 3.5 μm is plotted for the case where a LaPO ₄ : Ce phosphor (second phosphor) is mixed, and the luminance retention ratio is larger when the mixing amount of the LaPO ₄ : Ce phosphor is larger. However, it can be seen that it is lower than the case of the solid line of the present invention. Thus, by coating the first phosphor with the second phosphor of fine particles, compared to the case where the second phosphor is mixed,
It can be seen that the deterioration with time of the luminance can be suppressed.
This is because, when the first phosphor and the second phosphor are mixed, vacuum ultraviolet rays are also directly applied to the first phosphor, so that the luminance deteriorates significantly with time. In the case of coating with two phosphors, the vacuum ultraviolet rays are not directly irradiated on the first phosphor, and excite the second phosphor, which does not decrease in luminance due to the irradiation of the vacuum ultraviolet rays, to emit ultraviolet rays to blue light. This is because the first phosphor is excited by ultraviolet to blue light emitted by the two phosphors and emits visible light, so that deterioration of luminance over time is reduced.

Similarly, the above BaMgAl_TenO₁₇: Eu firefly
The specific surface area is 6.1 m on the particle surface of the light body (first phosphor).^Two
/ G, LaPO having an average particle size of 0.8 μm_Four: Ce phosphor
(Second phosphor), LaPO_Four:
The relative luminance with respect to the Ce phosphor coverage is plotted with a solid line in FIG.
Lot. Relative luminance is vacuum ultraviolet light with a wavelength of 147 nm
It is a measured value when excited by. From this figure, LaPO
_Four: When the coating amount of the Ce phosphor exceeds 80 parts by weight,
The decrease is large, and if it exceeds 100 parts by weight, the brightness is further increased.
It can be seen that is decreased. Also, the dashed line in the figure is the comparative example.
And BaMgAl _TenO₁₇: B for Eu phosphor_TwoO_ThreeCovered
It is plotted for the case where
When it is increased, the brightness is greatly reduced compared to the case of the solid line of the present invention.
You can see that Thus, the first phosphor has fine particles.
By coating the second phosphor, B_TwoO_ThreeWhen coated
In comparison, it can be seen that a decrease in luminance can be suppressed.
This is B_TwoO_ThreeWhen coated, B_TwoO_ThreeIs vacuum ultraviolet excitation
Does not emit light at all, whereas the first phosphor
If two phosphors are coated, the second phosphor is vacuum ultraviolet
When excited, it emits ultraviolet to blue light, and further emits purple
Excitation of the first phosphor with external light to blue light to emit visible light
Therefore, a decrease in luminance due to coating can be reduced.

From the above, BaMgAl ₁₀ O ₁₇ : E
LaPO on the particle surfaces of u phosphor _4: If coated with Ce phosphor, LaPO _4: coverage of Ce phosphor, BaMg
Al _{1 0} O _17: 0.5~1 to Eu phosphor 100 parts by weight
It is understood that the range of 00 parts by weight is preferable, and the range of 20 to 80 parts by weight is more preferable.

[0015] Next, BaMgAl ₁₀ O _17: the particle surfaces of the Eu phosphor, LaPO _4: for the case where Ce phosphor covers 20 parts by weight, LaPO _4: 3 luminance maintenance rate vs. the specific surface area of Ce phosphor Are plotted. From this figure, it can be seen that the luminance maintenance ratio is high when the specific surface area of the LaPO ₄ : Ce phosphor is 3 m ² / g or more.

[0016] Similarly, BaMgAl ₁₀ O _17: Eu-phosphor particle surface, LaPO _4: for the case where Ce phosphor covers 20 parts by weight, LaPO _4: the relative brightness in FIG. 4 for the specific surface area of Ce phosphor Plotted. From this figure, it can be seen that the luminance decreases when the specific surface area of the LaPO ₄ : Ce phosphor exceeds 50 m ² / g.

From the above, BaMgAl ₁₀ O ₁₇ : E
LaPO on the particle surfaces of u phosphor _4: If coated with Ce phosphor, LaPO _4: specific surface area of Ce phosphor, 3-5
It turns out that the range of 0 m < ² > / g is preferable.

The specific surface area is a value measured by a constant pressure BET one-point method by nitrogen gas adsorption.
The specific surface area is measured by an air permeation method, and the average value of the particle diameters of the primary particles is obtained. This is a value measured using a Fisher Sub-Sieve Sizer (FSSS).

In general, the ultraviolet light used for exciting the phosphor is mainly 365 nm from a high-pressure mercury lamp, 253.7 nm obtained with high efficiency from a low-pressure mercury vapor discharge, 184.9 nm partially radiated from the discharge, xenon. There is 147 nm ultraviolet light emitted from the discharge. The shorter the wavelength of ultraviolet light, the lower the transmission power, and conversely, the longer the wavelength of ultraviolet light, the higher the transmission power. That is, it is relatively near the surface of the phosphor that is excited by the vacuum ultraviolet ray of 184.9 nm or 147 nm. Therefore, by coating the particle surface of the first phosphor with the second phosphor of fine particles, the vacuum ultraviolet light does not directly irradiate the first phosphor, but excites the second phosphor on the surface to emit ultraviolet to blue light. It emits light. Furthermore, the first phosphor is excited by ultraviolet to blue light emitted by the second phosphor, and emits visible light. And even when the first phosphor has a problem that the luminance is reduced by the irradiation of the vacuum ultraviolet ray, the vacuum ultraviolet ray is not directly radiated to the first phosphor, and the second phosphor is not reduced in the luminance by the irradiation of the vacuum ultraviolet ray. Is excited to emit ultraviolet to blue light, so that a phosphor with very little deterioration in luminance over time can be obtained. Also,
By covering the second phosphor that emits ultraviolet to blue light when excited by vacuum ultraviolet light in this manner, B ₂ that does not emit light can be obtained.
It is possible to obtain a phosphor with a very small decrease in luminance due to the coating as compared with the case where the coating is made of O ₃ , Sb ₂ O ₃ or the like.

Hereinafter, embodiments of the present invention will be described, but it goes without saying that the present invention is not limited to only specific embodiments.

[0021]

[Example 1] BaMgA was used as the first phosphor.
A l ₁₀ O ₁₇ : Eu phosphor is prepared as follows. The following are weighed as raw materials, and BaCO ₃ ······· 0.90 mol 3MgCO ₃ · Mg (OH) ₂ · 3H ₂ O ··· 0.25 Mol γ-Al ₂ O ₃ 5.00 mol Eu ₂ O ₃ 0.05 Mol 1.0 parts by weight of Al to 100 parts by weight of these
It was added F _3, mixed ball mill in the magnetic pot. The obtained mixed raw material is filled in an alumina crucible with a lid, and fired in air at 1500 ° C. for 8 hours. After cooling, it is further fired at 1500 ° C. for 8 hours in a reducing atmosphere of N ₂ —H ₂ . After cooling, wet dispersion treatment is performed, and after passing through a 300 mesh sieve,
Dehydrate and dry. Thus, the average particle size is 2.0 μm
BaMgAl ₁₀ O ₁₇ : Eu phosphor is obtained. The obtained phosphor emits blue light when excited by ultraviolet light.

Further, LaPO ₄ : C is used as the second phosphor.
An e-phosphor is produced as follows. The following are weighed as raw materials, and La ₂ O ₃ ... 0.40 mol CeO ₂ . 0.20 mol (NH ₄ ) ₂ HPO ₄ 1.00 mol All of these are mixed in a ball mill in a magnetic pot. The obtained mixed raw material was filled in an alumina crucible with a lid, and N ₂ −
Baking at 950 ° C. for 3 hours in a reducing atmosphere of H ₂ . After cooling, wet dispersion treatment, dehydration drying, and specific surface area of 6.1 m
^{A 2} / g LaPO ₄ : Ce phosphor having an average particle size of 0.8 μm is obtained. The obtained phosphor has a main peak of 3 when excited by vacuum ultraviolet light.
Emit ultraviolet light of 18 nm.

Next, the first phosphor is coated with the second phosphor by mechanofusion. That is, 1000 g of the first phosphor and 200 g of the second phosphor are put in a container, and are coated by rotating at a speed of 2000 rpm for 20 minutes, and 20 parts by weight of the second phosphor is coated with respect to 100 parts by weight of the first phosphor. To obtain a fluorescent material excited by vacuum ultraviolet light.

[Example 2] In the same manner as in Example 1 except that the coating amount of the second phosphor was changed to 5 g, 0.5 parts by weight of the second phosphor was coated with respect to 100 parts by weight of the first phosphor. To obtain a fluorescent material excited by vacuum ultraviolet light.

Example 3 The coating amount of the second phosphor was 10 g.
Except that the first phosphor 100
A VUV-excited light-emitting phosphor in which 1 part by weight of the second phosphor is coated per part by weight is obtained.

Example 4 The coating amount of the second phosphor was 50 g.
Except that the first phosphor 100
A VUV-excited light-emitting phosphor is obtained in which 5 parts by weight of the second phosphor is coated per part by weight.

Example 5 The coating amount of the second phosphor was 500
g of the first phosphor 10
A VUV-excited phosphor is obtained in which 50 parts by weight of the second phosphor is coated with respect to 0 part by weight.

Example 6 The coating amount of the second phosphor was 100
Except for making the first phosphor 1
A VUV-excited phosphor is obtained in which 100 parts by weight of the second phosphor is coated with respect to 00 parts by weight.

Example 7 A specific surface area of 3.50 parts by weight of the first phosphor was obtained in the same manner as in Example 1 except that the sintering temperature during the production of the LaPO ₄ : Ce phosphor was 1000 ° C.
0 m ² / g, an average particle size of 1.0 .mu.m LaPO _4: Ce phosphor to obtain a vacuum ultraviolet excitation light emitting phosphor coated 20 parts by weight.

Example 8 The same procedure as in Example 1 was carried out except that the sintering temperature during the production of the LaPO ₄ : Ce phosphor was set to 800 ° C., and the specific surface area was 16 m with respect to 100 parts by weight of the first phosphor.
^A VUV-excited luminescent phosphor coated with 20 parts by weight of a LaPO ₄ : Ce phosphor having an average particle diameter of 0.5 μm or less is obtained.

Example 9 The same procedure as in Example 1 was carried out except that the sintering temperature during the production of the LaPO ₄ : Ce phosphor was set at 700 ° C., and the specific surface area was 50 m with respect to 100 parts by weight of the first phosphor.
^A VUV-excited luminescent phosphor coated with 20 parts by weight of a LaPO ₄ : Ce phosphor having an average particle diameter of 0.5 μm or less is obtained.

Example 10 YP was used as the second phosphor.
In the same manner as in Example 1 except that the O ₄ : Ce phosphor is used, a VUV-excited luminescent phosphor in which 20 parts by weight of the YPO ₄ : Ce phosphor is coated with respect to 100 parts by weight of the first phosphor is obtained. Here, the second phosphor YPO ₄ : Ce phosphor is prepared as follows. The following are weighed as raw materials, and Y ₂ O ₃ ········· 0.40 mol CeO ₂ ······ 0.20 mol (NH ₄ ) ₂ HPO ₄ 1.00 mol All of these are mixed in a ball mill in a magnetic pot. The obtained mixed raw material was filled in an alumina crucible with a lid, and N ₂ −
Baking at 950 ° C. for 3 hours in a reducing atmosphere of H ₂ . After cooling, wet dispersion treatment, dehydration drying, and specific surface area of 10.2
A YPO ₄ : Ce phosphor having m ² / g and an average particle diameter of 0.8 μm is obtained. The obtained phosphor has a main peak of 3 when excited by vacuum ultraviolet light.
It emits 57 nm ultraviolet light.

[Embodiment 11] Y ₂ Si as the second phosphor
In the same manner as in Example 1 except that the O ₅ : Ce phosphor is used, a VUV-excited luminescent phosphor coated with 20 parts by weight of Y ₂ SiO ₅ : Ce per 100 parts by weight of the first phosphor is used. obtain. Here, the second phosphor Y ₂ SiO ₅ : Ce phosphor is prepared as follows. The following are weighed as raw materials, and Y ₂ O ₃ ········· 0.993 mol CeO ₂ ····· 0.007 mol SiO ₂ 1.000 mol All of these are mixed in a ball mill in a magnetic pot. The obtained mixed raw material is filled in an alumina crucible with a lid, and fired in air at 1350 ° C. for 6 hours. After cooling, wet dispersion treatment and dehydration drying are performed to obtain a Y ₂ SiO ₅ : Ce phosphor having a specific surface area of 6.8 m ² / g and an average particle diameter of 0.8 μm. The obtained phosphor emits ultraviolet light having a main peak of 398 nm when excited by vacuum ultraviolet light.

Example 12 The coating amount of the second phosphor was 50
g of the first phosphor 1
A VUV-excited phosphor is obtained in which 5 parts by weight of the second phosphor is coated with respect to 00 parts by weight.

Example 13 The coating amount of the second phosphor was 10
In the same manner as in Example 11 except that the amount is set to 0 g, a VUV-excited light-emitting phosphor in which the second phosphor is coated by 10 parts by weight with respect to 100 parts by weight of the first phosphor is obtained.

Example 14 The coating amount of the second phosphor was 40
In the same manner as in Example 11, except that the amount is set to 0 g, a VUV-excited light-emitting phosphor in which the second phosphor is coated by 40 parts by weight with respect to 100 parts by weight of the first phosphor is obtained.

Embodiment 15 As the second phosphor, Y (P,
V) O_FourThe same as in Example 1 except that a phosphor is used.
Therefore, Y (P, V) O is used for 100 parts by weight of the first phosphor._Fourfirefly
VUV-excited light-emitting phosphor coated with 20 parts by weight of light body
Get. Here, the second phosphor Y (P, V) O _FourPhosphor
Is manufactured as follows. Weigh the following as raw materials
Weigh, Y_TwoO_Three ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 1.00mol (NH_Four)_TwoHPO_Four..... 0.85 mol NH_FourVO_Three0.15 mol All of these are mixed in a ball mill in a magnetic pot. Profit
Filled raw material into an alumina crucible with a lid,
At 1250 ° C. for 4 hours. Wet dispersion treatment after cooling
And dehydrated and dried to obtain a specific surface area of 15.5 m.^Two/ G, average grain
0.6 μm diameter Y (P, V) O_FourObtain phosphor. Obtained
Phosphor has blue main peak of 418 nm when excited by vacuum ultraviolet light.
Emit colored light.

Example 16 The coating amount of the second phosphor was 10
In the same manner as in Example 15 except that the amount is set to 0 g, a VUV-excited light-emitting phosphor is obtained in which 100 parts by weight of the first phosphor is coated with 10 parts by weight of the second phosphor.

Comparative Example 1 A VUV-excited phosphor was obtained in the same manner as in Example 1 except that the first phosphor was not coated with the second phosphor.

Comparative Example 2 Example 1 was used as the first phosphor.
Using the BaMgAl ₁₀ O ₁₇ : Eu phosphor obtained in
As the second phosphor, a LaPO ₄ : Ce phosphor is prepared as follows. The following are weighed as raw materials, and La ₂ O ₃ ... 0.40 mol CeO ₂ . 0.20 mol (NH ₄ ) ₂ HPO ₄ 1.00 mol 0.5 parts by weight of H ₃ with respect to 100 parts by weight of the total amount
Add BO ₃ and ball mill mix in a magnetic pot.
The obtained mixed raw material was filled in an alumina crucible with a lid, and N ₂
Baking at 1200 ° C. for 3 hours in a reducing atmosphere of —H ₂ . After cooling, wet dispersion treatment, dehydration drying, and LaPO ₄ : C having a specific surface area of 0.45 m ² / g and an average particle size of 3.5 μm are performed.
e phosphor is obtained. Next, 1000 g of the first phosphor and 200 g of the second phosphor were dry-mixed to form the first phosphor 10.
A vacuum ultraviolet ray excited light emitting phosphor in which 20 parts by weight of the second phosphor is mixed with respect to 0 part by weight is obtained.

Comparative Example 3 BaMg obtained in Example 1
Al ₁₀ O ₁₇ : 14 g of B ₂ O ₃ and water 1 per 100 g of Eu phosphor
After adding and mixing 00 g to form a slurry, the slurry is dried at 100 ° C. After drying, the mixture is filled in an alumina crucible and fired at 400 ° C. for 1 hour in the air using an electric furnace to obtain a vacuum ultraviolet-excitation phosphor.

The relative luminance and luminance maintenance ratio of the VUV-excited light-emitting phosphors obtained in Examples 1 to 10 and Comparative Examples 1 to 3 were measured, and the results are summarized in Table 1. 147n relative brightness
It is a measured value when excited by vacuum ultraviolet light of wavelength m,
The brightness maintenance ratio is the relative brightness before deterioration by the rare gas discharge tube,
It is calculated as a percentage of the value divided by the relative luminance after deterioration.

[0043]

[Table 1]

[0044]

As described above, the surface of the particles of the first phosphor that emits light when excited by vacuum ultraviolet light and ultraviolet to blue light is coated with the second phosphor that emits ultraviolet light to blue light when excited by vacuum ultraviolet light. By doing so, it is possible to suppress the deterioration with time of the luminance of the phosphor due to vacuum ultraviolet rays. Furthermore, by using the phosphor of the present invention, the ratio of radiant energy of a color plasma display panel or a xenon discharge type fluorescent lamp using ultraviolet light, particularly 147 nm vacuum ultraviolet light of mainly xenon, or 184.9 nm is relatively large. It is possible to improve the working characteristics of a light-emitting device such as a high-load fluorescent lamp.

[Brief description of the drawings]

FIG. 1 is a characteristic diagram showing a relationship between a luminance maintenance ratio and an amount of a second phosphor.

FIG. 2 is a characteristic diagram showing a relationship between a relative luminance and a covering amount.

FIG. 3 is a characteristic diagram showing a relationship between a luminance maintenance ratio and a specific surface area of a second phosphor.

FIG. 4 is a characteristic diagram showing a relationship between relative luminance and a specific surface area of a second phosphor.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09K 11/71 CPW C09K 11/71 CPW 11/78 CPB 11/78 CPB 11/79 CPR 11/79 CPR 11 / 81 CPW 11/81 CPW 11/83 CQA 11/83 CQA H01J 11/02 H01J 11/02 B 61/44 61/44 N (72) Inventor Mie Watanabe Mie 491-1 Kagaminakacho, Anan-shi, Tokushima 100 Nichia F-term (reference) within Kagaku Kogyo Co., Ltd.

Claims (3)

[Claims] 1. A specific phosphor having a specific surface area of 3
A VUV-excited luminescent phosphor coated with 0.5 to 100 parts by weight of a second phosphor of 〜50 m ² / g per 100 parts by weight of the first phosphor, wherein the first phosphor is a vacuum ultraviolet ray A phosphor that is excited and emits light in the visible region, wherein the second phosphor is a phosphor that is excited by vacuum ultraviolet light and has an emission peak wavelength in a wavelength region of 200 to 450 nm, and the first phosphor is the second phosphor A vacuum ultraviolet-excited light-emitting phosphor characterized by being excited by light emitted from the phosphor and emitting light. 2. The method according to claim 1, wherein the first phosphor is BaMgAl._TenO₁₇:
Eu, BaMgAl _TenO₁₇: Eu, Mn, BaAl₁₂O
₁₉: Mn, SrAl_TwoO_Four: Eu, Sr_FourAl_{1 Four}O_{twenty five}: E
u, Y_TwoO_Three: Eu, (Y, Gd)_TwoO_Three: A group consisting of Eu
At least one kind selected from
The vacuum ultraviolet ray excited light emitting phosphor according to claim 1. 3. The method according to claim 2, wherein the second phosphor is BaSi._TwoO_Five: Pb,
(Ba, Sr, Mg)_ThreeSi_TwoO₇: Pb, SrB_FourO₇:
Eu, (Ca, Zn)_Three(PO_Four)_Two: Tl, Ca_Three(PO
_Four)_Two: Tl, YPO_Four: Ce, LaPO_Four: Ce, Y
(P, V) O_Four, Y _TwoSiO_Five: Ce, CaWO_Four, CaW
O_Four: At least one selected from the group consisting of Pb
The vacuum ultraviolet ray according to claim 1 or 2, wherein
Excitation phosphor.