JP2005068343A - Vacuum ultraviolet excitation phosphor and plasma display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vacuum ultraviolet excitation phosphor that has excellent ion bombardment luminance maintenance rate and vacuum ultraviolet (VUV) luminance maintenance rate. <P>SOLUTION: The vacuum ultraviolet excitation phosphor is constituted from a powder of vacuum ultraviolet excitation phosphor and a coating layer that coats the surface of the particle bodies of the phosphor at least partially. In this case, the main body of powdery particles is manganese-activated zinc silicate and the coating layer is constituted with at least one selected from the group consisting of aluminum fluoride, gadolinium fluoride, lanthanum fluoride, yttrium fluoride and ammonium fluoride. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a vacuum ultraviolet excitation phosphor used for a plasma display panel (hereinafter also referred to as “PDP”), a high load fluorescent lamp, a rare gas discharge lamp, and the like. Specifically, the present invention relates to a vacuum ultraviolet-excited phosphor (hereinafter also referred to as “phosphor”) having an improved luminance maintenance rate and a plasma display panel using the phosphor.

The PDP is formed by separating a sealed gas space sandwiched between two glass plates by partition walls and arranging minute discharge spaces called display cells in a matrix. Each display cell is coated with phosphors that emit red, blue, and green, and these phosphors emit light when excited by vacuum ultraviolet rays generated by discharge.
In addition, the rare gas discharge lamp is coated with a three-color phosphor mixed with phosphors that generate red, blue, and green on the inner wall of the glass tube, and emits light when excited by vacuum ultraviolet rays generated by the rare gas discharge. .
As the phosphor that emits green light, a vacuum ultraviolet-excited phosphor represented by Zn ₂ SiO ₄ : Mn is used.

Such a light-emitting device has a phosphor layer in the vicinity of the discharge space, and the emission luminance of a conventional vacuum ultraviolet-excited phosphor typified by Zn ₂ SiO ₄ : Mn greatly decreases with time. There is a need for further improvements.

  Patent Document 1 describes a phosphor characterized in that its surface is covered with at least one of an alkali metal fluoride and an alkaline earth metal fluoride. This phosphor prevents charged particles from directly colliding with the phosphor or contamination of the phosphor by Hg particles, etc., and therefore effectively prevents a decrease in luminance that could not be avoided conventionally. It is described that can be.

  However, this phosphor cannot sufficiently prevent a decrease in light emission luminance due to ion bombardment. Further, it was not possible to prevent a decrease in light emission luminance due to vacuum ultraviolet rays.

JP 52-156188 A

  An object of the present invention is to provide a vacuum ultraviolet excitation phosphor having an excellent ion bombardment luminance maintenance rate and a vacuum ultraviolet ray luminance maintenance rate (hereinafter referred to as “VUV luminance maintenance rate”).

  The vacuum ultraviolet-excited phosphor described in the present invention is a vacuum ultraviolet-excited phosphor composed of a powder having a powder body and a coating layer covering at least a part of the surface of the powder body, And manganese-activated zinc silicate, and the coating layer is made of at least one selected from the group consisting of aluminum fluoride, gadolinium fluoride, lanthanum fluoride, yttrium fluoride, and ammonium fluoride.

  The vacuum ultraviolet-excited phosphor described in the present invention is a vacuum ultraviolet-excited phosphor composed of a powder having a powder body and a coating layer covering at least a part of the surface of the powder body, , Manganese-activated zinc silicate, and the coating layer is made of fluoride, and the amount of the fluoride is less than 1% by weight with respect to the powder body.

  The fluoride is at least one selected from the group consisting of magnesium fluoride, barium fluoride, lithium fluoride, aluminum fluoride, gadolinium fluoride, calcium fluoride, lanthanum fluoride, yttrium fluoride, and ammonium fluoride. Preferably there is.

  The coating layer preferably forms microcapsules.

  The covering layer preferably has a multilayer structure made of a plurality of different materials.

  The coating layer having the multilayer structure preferably has a large refractive index on the powder body side and a small refractive index on the phosphor surface side.

  The powder body has at least one selected from the group consisting of magnesium, calcium, strontium, barium, tin, yttrium, lanthanum and europium, and at least one selected from the group consisting of germanium, gadolinium, gallium and sulfur. Manganese activated zinc silicate is preferred.

  The manganese-activated zinc silicate is preferably activated by 0.2 to 1.0% by weight of manganese relative to zinc silicate.

The powder body has the general formula ^{_{(Zn 1-a-b,}} M 1 a, Mn b) 2 (Si 1-c, M 2 c) O 4 (M 1 is magnesium, calcium, strontium, barium, tin, yttrium Represents at least one selected from the group consisting of lanthanum and europium, M ² represents at least one selected from the group consisting of germanium, gadolinium, gallium and sulfur, and a is a number satisfying 0 ≦ a ≦ 0.05 And b represents a number satisfying 0.005 ≦ b ≦ 0.2, and c represents a number satisfying 0 ≦ c ≦ 0.05.

  The powder body preferably has a specific surface area of 1.0 to 8.0 μm.

  The plasma display panel of the present invention is a plasma display panel using the vacuum ultraviolet ray-excited phosphor according to any one of the present invention.

At least one selected from the group consisting of aluminum fluoride, gadolinium fluoride, lanthanum fluoride, yttrium fluoride, and ammonium fluoride, which is a coating layer, is a protective film against ion collision while transmitting vacuum ultraviolet light To play a role. Therefore, the ion bombardment luminance maintenance ratio can be improved while maintaining high luminance.
Further, a manganese-activated zinc silicate phosphor that is a powder body by forming at least one selected from the group consisting of aluminum fluoride, gadolinium fluoride, lanthanum fluoride, yttrium fluoride, and ammonium fluoride as a coating layer It is thought that oxidation of manganese can be prevented. Thereby, modification | denaturation of the powder main body by vacuum ultraviolet rays can be prevented, and a VUV brightness | luminance maintenance factor can be improved.

Since the coating layer is made of fluoride and the amount of fluoride is less than 1% by weight with respect to the powder body, the fluoride plays a role of a protective film against ion collision while transmitting vacuum ultraviolet rays. Thereby, it is possible to achieve both high luminance and improvement of the ion bombardment luminance maintenance rate.
Moreover, it is thought that fluoride can prevent the oxidation of manganese of the manganese-activated zinc silicate phosphor that is the powder body. Thereby, modification | denaturation of the powder main body by vacuum ultraviolet rays can be prevented, and a VUV brightness | luminance maintenance factor can be improved.
The effect is that at least the fluoride is selected from the group consisting of magnesium fluoride, barium fluoride, lithium fluoride, aluminum fluoride, gadolinium fluoride, calcium fluoride, lanthanum fluoride, yttrium fluoride, and ammonium fluoride. It appears remarkably when it is one type.

  When the coating layer forms microcapsules, the function as a protective film of fluoride is improved, so that the ion bombardment luminance maintenance rate is further improved.

  Since the coating layer has a multilayer structure made of a plurality of different materials, the function as a fluoride protective film is improved, and the ion bombardment luminance maintenance rate is further improved.

  In a multi-layer coating layer, increasing the refractive index on the powder body side and decreasing the refractive index on the phosphor surface side makes it easier to emit light generated by the manganese-activated zinc silicate powder body. . Thereby, a phosphor with higher luminance can be obtained without impairing the high ion bombardment luminance maintenance rate.

Manganese whose powder body has at least one selected from the group consisting of magnesium, calcium, strontium, barium, tin, yttrium, lanthanum and europium and at least one selected from the group consisting of germanium, gadolinium, gallium and sulfur By using activated zinc silicate, the ion bombardment luminance maintenance ratio and the VUV luminance maintenance ratio can be further improved.
This effect has at least one selected from the group consisting of magnesium, calcium, strontium, barium, tin, yttrium, lanthanum and europium at the Zn site, and a group consisting of germanium, gadolinium, gallium and sulfur at the Si site. It appears remarkably when it has at least one selected from

  By being manganese-activated zinc silicate activated with 0.2 to 1.0% by weight of manganese with respect to zinc silicate, without impairing the improvement of the ion impact luminance maintenance rate and VUV luminance maintenance rate, Afterglow does not occur and a high-luminance phosphor can be obtained.

  When the specific surface area of the powder body is 2.0 to 8.0 μm, the coating characteristics are improved without impairing the improvement of the ion bombardment luminance maintenance rate and the VUV luminance maintenance rate, and the discharge starting voltage when used in a PDP. Can be reduced.

  Since the plasma display panel using the vacuum ultraviolet-excited phosphor according to any one of the present invention improves the ion impact luminance maintenance rate and the VUV luminance maintenance rate of the PDP phosphor, a high-quality PDP can be obtained. It is done.

  The vacuum ultraviolet excitation phosphor according to the present invention will be specifically described below. However, the present invention is not limited to this embodiment, examples, and FIG.

The vacuum ultraviolet-excited phosphor of the present invention comprises a powder having a powder body and a coating layer covering at least a part of the surface of the powder body.
The powder body is manganese activated zinc silicate.
When the composition ratio of Zn, Mn, Si and O of the manganese-activated zinc silicate is represented by the general formula (Zn _1-b , Mn _b ) ₂ SiO ₄ , b satisfies 0.005 ≦ b ≦ 0.2. It is preferable to represent the number to satisfy.
b is preferably 0.01 or more, and preferably 0.1 or less. When b is in this range, no afterglow occurs and a high-luminance phosphor can be obtained.

  In the vacuum ultraviolet excitation phosphor of the present invention, the powder body is present in the form of particles. Specifically, the powder body exists in the form of particles composed of one or both of primary particles and secondary particles that are aggregates thereof. That is, the powder body exists in the form of particles, and the particles may be composed only of primary particles, or may be composed only of secondary particles that are aggregates of primary particles. It may consist of both particles.

In the vacuum ultraviolet-excited phosphor of the present invention, the powder body has a general formula (Zn ₁ -ab, M ¹ _a , Mn _b ) ₂ (Si _{1 -c} , M ² _c ) O ₄ (M ¹ is magnesium, Represents at least one selected from the group consisting of calcium, strontium, barium, tin, yttrium, lanthanum and europium, M ² represents at least one selected from the group consisting of germanium, gadolinium, gallium and sulfur, and a is 0 ≦ a ≦ 0.05, b represents a number satisfying 0.005 ≦ b ≦ 0.2, and c represents a number satisfying 0 ≦ c ≦ 0.05. Is preferred.
a is preferably larger than 0, and preferably 0.01 or less. When a is in this range, the ion bombardment luminance maintenance ratio and the VUV luminance maintenance ratio can be further improved.
b is preferably 0.01 or more, and preferably 0.1 or less. When b is in this range, no afterglow occurs and a high-luminance phosphor can be obtained.
c is preferably larger than 0, and is preferably 0.01 or less. When c is within this range, the ion bombardment luminance maintenance ratio and the VUV luminance maintenance ratio can be further improved.

  The following aspects are mentioned as a suitable aspect of the powder main body in the vacuum ultraviolet-excited fluorescent substance of this invention.

The powder body has at least one selected from the group consisting of magnesium, calcium, strontium, barium, tin, yttrium, lanthanum and europium, and at least one selected from the group consisting of germanium, gadolinium, gallium and sulfur, An embodiment represented by the general formula (Zn _1-b , Mn _b ) ₂ SiO ₄ (b represents a number satisfying 0.005 ≦ b ≦ 0.2).
b is preferably 0.01 or more, and preferably 0.1 or less. When b is in this range, no afterglow occurs and a high-luminance phosphor can be obtained.

  In the present invention, the manganese-activated zinc silicate is more preferably 0.3% by weight or more, and more preferably 0.8% by weight or less of manganese with respect to zinc silicate. If the amount of manganese is too small relative to zinc silicate, manganese-activated zinc silicate does not emit light, and afterglow occurs even if it emits light. If the amount of manganese is too much relative to zinc silicate, the brightness is lowered and the phosphor is deteriorated.

In the present invention, the specific surface area diameter of the powder body is preferably 2.0 μm or more, and preferably 7.0 μm or less. When the specific surface area diameter is too small, the coating properties are deteriorated, and the discharge start voltage becomes high when used for PDP. If the specific surface area is too large, the luminance will be low, and the discharge starting voltage will be high when used for PDP.
The method for measuring the specific surface area diameter is not particularly limited. For example, it can be measured using a Fischer sub-sieve sizer (FSSS) by the air permeation method.

  Moreover, the shape of the powder body is not limited to a spherical shape. Depending on the growth conditions and growth conditions of the powder body, the shape of the phosphor particles may be polygonal or irregular, resulting in an irregular shape.

The coating layer is made of fluoride. The fluoride is at least one selected from the group consisting of magnesium fluoride, barium fluoride, lithium fluoride, aluminum fluoride, gadolinium fluoride, calcium fluoride, lanthanum fluoride, yttrium fluoride, and ammonium fluoride. Is preferred.
More preferably, it is at least one selected from the group consisting of aluminum fluoride, gadolinium fluoride, lanthanum fluoride, yttrium fluoride, and ammonium fluoride.

  In the present invention, the amount of fluoride is preferably 0.01% by weight or more, and preferably 0.8% by weight or less, based on the powder body. If the amount of fluoride with respect to the powder body is too small, sufficient improvement in the ion bombardment luminance maintenance rate and the VUV luminance maintenance rate is not observed. If the amount of fluoride relative to the powder body is too large, the luminance of the phosphor is lowered.

FIG. 1 shows a state in which the powder body is coated with a coating layer.
FIG. 1A shows a state in which the powder body 11b is coated with the film-shaped coating layer 12, and FIG. 1B shows a state in which the powder body 11b is coated with the particulate coating layer 12b. As shown in this figure, the coating layer can be a microcapsule covered with a film or a microcapsule covered with particles.
FIG. 1C shows an example in which these microcapsules are formed of a multilayer film. When the coating layer is formed of a multilayer film, the light generated in the powder body 11b is externally increased by increasing the refractive index of the coating layer 12c on the side in contact with the powder body 11b or by decreasing the refractive index of the outer coating layer 12d. Easy to release. In addition, although the example which comprised the coating layer by 2 layers is shown in FIG.1 (c), it can also be set as the structure of 3 layers or more.
In the example of the above figure, the cross-sectional view of the phosphor particles is shown in a substantially circular shape, but the present embodiment is not limited to this example, and as shown in FIG. 12e can be coated and used.

  The production method of the ultraviolet-excited phosphor of the present invention is not particularly limited. For example, it can be produced as in the following (1) and (2).

(1) Production of powder body (i) Production of raw material mixture Compounds described below are mixed so that each constituent element has a predetermined composition ratio to obtain a raw material mixture. The compound used for the raw material mixture is selected according to the elements constituting the target composition.
The mixing method is not particularly limited, for example, a method of mixing powdery compounds as they are to obtain a raw material mixture; mixing in a slurry form using water and / or an organic solvent, and then drying to obtain a raw material mixture Method: A method in which an aqueous solution of the above-mentioned compound is mixed and precipitated, and the resulting precipitate is dried to obtain a raw material mixture; a method in which these are used in combination.

Below, the compound used for a raw material mixture is illustrated.
The zinc compound is not particularly limited, and examples thereof include oxides (for example, Zn ₂ O, ZnO, ZnO ₂ ), hydroxides, zinc carbonate, and zinc sulfate. Of these, ZnO, ZnCO ₃ , and ZnSO ₄ are preferable.

The silicon compound is not particularly limited, for example, oxides (e.g., SiO, _SiO 2), silanes, silicic acid, silicates. Of these, SiO ₂ and orthosilicic acid are preferable.

The manganese compound is not particularly limited. For example, manganese metal, oxide (eg, MnO ₂ , Mn ₂ O ₃ , Mn ₃ O ₄ ), hydroxide, nitrate, carbonate (MnCO ₃ ), chloride salt, Examples thereof include manganese iodide, manganese sulfate, and manganese acetate. Among these, MnCO ₃ , MnSO ₄ , and Mn (CH ₃ COO) ₂ are preferable.

Magnesium compound is not particularly limited, for _{example, MgO, MgCO 3, Mg (} OH) 2, MgCl 2, MgSO 4, Mg (NO 3) 2, Mg (CH 3 COO) 2, magnesium iodide, perchlorate Examples include magnesium. Of these, MgO and MgSO ₄ are preferable.

Calcium compound is not particularly limited, for _{example, CaO, CaCO 3, Ca (} OH) 2, CaCl 2, CaSO 4, Ca (NO 3) 2, Ca (CH 3 COO) 2 and the like. Of these, CaO and CaCO ₃ are preferable.

Strontium compound is not particularly limited, for _example, SrO, is _{SrO 2, Sr (OH) 2} , SrSO 4 and the like. Of these, SrO and SrSO ₄ are preferable.

The barium compound is not particularly limited, and examples thereof include BaO, BaO ₂ , Ba (OH) ₂ , and BaCl ₂ . Of these, BaO and BaCl ₂ are preferable.

Tin compounds include, but are not limited to, for _{example, SnO, SnO 2, Sn (} OH) 2, SnSO 4 , and the like. Of these, SnO and SnSO ₄ are preferable.

Yttrium compound is not particularly limited, for _{example, Y 2 O 3, Y (} OH) 3, Y 2 (SO 4) 3, Y 2 (CO 3) 3 and the like. Among these, yttrium metal, Y ₂ O ₃ , and Y (OH) ₃ are preferable.

Lanthanum compound is not particularly limited, for _{example, LaO, La 2 O 3,} La (OH) 3, La 2 (SO 4) 3 and the like. Of these, lanthanum metal, LaO, and La (OH) ₃ are preferable.

Europium compound is not particularly limited, for _{example, EuO, Eu 2 O 3,} Eu (OH) 2, EuSO 4, Eu 2 (SO 4) 3, Eu is (CH _{3 COO)} 3 and the like. Of these, EuO and Eu (CH ₃ COO) ₃ are preferable.

Germanium compound is not particularly limited, for _{example, GeO 2, Ge (OH)} 2, Ge (CH 3) 4, Ge (C 2 H 5) 4 and the like. Of these, GeO ₂ and Ge (OH) ₂ are preferable.

Gadolinium compound is not particularly limited, for _{example, Gd 2 O 3, Gd 2} (SO 4) 3 and the like. Among these, Gd ₂ O ₃ is preferable.

Gallium compound is not particularly limited, for _{example, Ga 2 O, Ga 2 O} 3, Ga (OH) 3, Ga 2 (CO 3) 3 and the like. Among these, Ga ₂ O and Ga (OH) ₃ are preferable.

The sulfur compound is not particularly limited. For example, Li ₂ SO ₄ , MnSO ₄ , (NH ₄ ) ₂ SO ₄ , Al ₂ (SO ₄ ) ₃ , MgSO ₄ , sulfide, sulfur iodide, hydrogen sulfide, sulfuric acid and The salt and nitrogen sulfide are mentioned. Among these, MnSO ₄ , (NH ₄ ) ₂ SO ₄ , Al ₂ (SO ₄ ) ₃ , and MgSO ₄ are preferable.
Moreover, you may use the compound containing 2 or more types of each element mentioned above.

(Ii) Firing and grinding of raw material mixture Next, the raw material mixture is fired. The firing temperature, time, atmosphere, and the like are not particularly limited, and can be appropriately determined according to the purpose.
The firing temperature is preferably 1000 ° C. or higher, and more preferably 1200 ° C. or higher. If the firing temperature is too low, unreacted raw materials may remain in the powder body, and the original characteristics of the powder body may not be utilized. Further, the firing temperature is preferably 1400 ° C. or less, and more preferably 1300 ° C. or less. If the firing temperature is too high, the particle size of the powder body becomes too large, and the characteristics may deteriorate.
In general, the firing time is preferably 1 to 24 hours, and more preferably 6 to 12 hours. When the firing time is too short, the diffusion reaction between the raw material particles does not proceed. If the firing time is too long, firing after the diffusion reaction is almost completed is wasted, and coarse particles may be formed by sintering.

  Examples of the firing atmosphere include air, oxygen gas, a mixed gas of these with an inert gas such as nitrogen gas and argon gas, an atmosphere in which the oxygen concentration (oxygen partial pressure) is controlled, a weak oxidizing atmosphere, and a reducing atmosphere. . Of these, a reducing atmosphere is preferable.

After firing, if necessary, it can be ground using a rough mortar, ball mill, vibration mill, pin mill, jet mill, or the like to obtain a powder body having a desired particle size.
By pulverizing the agglomerated powder body, a powder body having a fracture surface can be obtained. Here, the fracture surface means a surface in which the powder body is torn and irregular polygons, spherical surfaces, slopes, etc. are formed partially or almost entirely. In the present specification, particles of a powder body having a fracture surface are sometimes referred to as fracture particles, while particles of a powder body having no fracture surface are sometimes referred to as growth particles. By providing a fracture surface in the powder body, it is possible to suppress variation in orientation of chromaticity and luminance.

  The fracture surface is formed entirely or partially of the powder body particles. However, it is not necessary to provide a fracture surface for every powder body. The degree of crushing of the powder body can be adjusted, and the powder body having a fracture surface and a powder body having no fracture surface can be mixed. Alternatively, grown particles may be mixed into the formed broken particles. In that case, it is good also as a powder main body from which a composition differs in a fracture | rupture particle | grain and a growth particle | grain. As a result, by forming or adjusting the powder body so as to partially include the fracture surface, an effect of suppressing variation in orientation of chromaticity and luminance can be obtained. The powder body thus formed may be classified by sieving or by different sedimentation characteristics.

  The powder main body of this invention can be obtained with the manufacturing method mentioned above.

(2) Formation of coating layer The obtained powder body is stirred and dispersed in pure water at 80 ° C or lower. It is preferable to stir and disperse at 30 to 60 ° C. The aqueous solution of the compound mentioned later is dripped here.
After depositing the coating layer on the surface of the powder body, the phosphor of the present invention can be obtained by separating and drying.
After drying, if desired, a sieve with a mesh dry sieve or the like can be used to obtain a phosphor having a desired average particle size or particle size distribution.

Below, the compound dripped in the aqueous solution of a powder main body is illustrated.
When the coating layer is made of magnesium fluoride, an aqueous solution of a magnesium compound and an aqueous solution of a fluorine compound are dropped.
When the coating layer is barium fluoride, an aqueous solution of a barium compound and an aqueous solution of a fluorine compound are dropped.
When the coating layer is lithium fluoride, an aqueous solution of a lithium compound and an aqueous solution of a fluorine compound are dropped.
When the coating layer is aluminum fluoride, an aqueous solution of an aluminum compound and an aqueous solution of a fluorine compound are dropped.
When the coating layer is gadolinium fluoride, an aqueous solution of a gadolinium compound and an aqueous solution of a fluorine compound are dropped.
When the coating layer is calcium fluoride, an aqueous solution of a calcium compound and an aqueous solution of a fluorine compound are dropped.
When the coating layer is lanthanum fluoride, an aqueous solution of a lanthanum compound and an aqueous solution of a fluorine compound are dropped.
When the coating layer is yttrium fluoride, an aqueous solution of an yttrium compound and an aqueous solution of a fluorine compound are dropped.
When the coating layer is ammonium fluoride, an aqueous solution of ammonium fluoride is dropped.

Fluorine compound is not particularly limited, for _example, NH 4 F, LiF, include MnF _2. Of these, NH ₄ F and MnF ₂ are preferable.

  The vacuum ultraviolet-excited phosphor of the present invention is suitably used for PDPs, high-load fluorescent lamps, and rare gas discharge lamps.

Using the vacuum ultraviolet excitation phosphor of the present invention, for example, a PDP can be produced as follows.
The phosphor particles for the three primary colors are mixed with a binder composed of a cellulose compound, a polymer compound such as polyvinyl alcohol, and an organic solvent to prepare a phosphor paste.
Phosphor paste is applied to the inner surface of the rear substrate by a method such as screen printing on the stripe-shaped substrate surface partitioned by the partition and provided with the address electrodes and the partition surface. This is dried to form each phosphor layer.
A surface glass substrate provided with a transparent electrode and a bus electrode in a direction orthogonal to the phosphor layer and provided with a dielectric layer and a protective layer on the inner surface is laminated and bonded thereto. A PDP is produced by reducing the inside to form a discharge space.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

1. Preparation of phosphor [Example 1]
Using manganese-activated zinc silicate obtained by the above-described method as a powder body, 100 g of this powder body is stirred and dispersed at 30 to 60 ° C. in pure water. To this are added dropwise a solution of 1.54 g of magnesium chloride in a 50 ml solution and a solution of 3.06 g of ammonium fluoride in a 50 ml solution at the same time. After depositing MgF ₂ on the surface of the powder body, separation, drying and sieving were performed to obtain a phosphor. MgF ₂ was 0.16 wt% relative to the powder body.

[Example 2]
A phosphor was obtained in the same manner as in Example 1 except that 7.68 g of magnesium chloride in a 50 ml solution and 15.29 g of ammonium fluoride in 50 ml solution were dropped simultaneously. MgF ₂ was deposited on the surface of the powder body. MgF ₂ was 3.93 wt% relative to the powder body.

Example 3
A phosphor was obtained in the same manner as in Example 1 except that 15.37 g of magnesium chloride in a 50 ml solution and 30.58 g of ammonium fluoride in 50 ml solution were dropped simultaneously. MgF ₂ was deposited on the surface of the powder body. MgF ₂ was 6.56 wt% relative to the powder body.

Example 4
A phosphor was obtained in the same manner as in Example 1 except that 1.54 g of magnesium chloride in 50 ml solution and 0.71 g of ammonium fluoride in 50 ml solution were dropped simultaneously. MgF ₂ was deposited on the surface of the powder body. MgF ₂ was 0.26 wt% relative to the powder body.

Example 5
A phosphor was obtained in the same manner as in Example 1 except that 0.77 g of magnesium chloride in 50 ml solution and 0.36 g of ammonium fluoride in 50 ml solution were dropped simultaneously. MgF ₂ was deposited on the surface of the powder body. MgF ₂ was 0.25 wt% relative to the powder body.

Example 6
A phosphor was obtained in the same manner as in Example 1 except that 0.15 g of magnesium chloride in 50 ml solution and 0.07 g of ammonium fluoride in 50 ml solution were dropped simultaneously. MgF ₂ was deposited on the surface of the powder body. MgF ₂ was 0.34 wt% relative to the powder body.

Example 7
A phosphor was obtained in the same manner as in Example 1 except that 3.35 g of barium chloride in 50 ml solution and 1.43 g of ammonium fluoride in 50 ml solution were dropped simultaneously. BaF ₂ was precipitated on the surface of the powder body.

Example 8
A phosphor was obtained in the same manner as in Example 1 except that 0.68 g of lithium chloride in 50 ml solution and 0.72 g of ammonium fluoride in 50 ml solution were dropped simultaneously. LiF was deposited on the surface of the powder body.

Example 9
A phosphor was obtained in the same manner as in Example 1 except that a solution of 3.86 g of aluminum chloride hexahydrate in a 50 ml solution and a solution of 1.95 g of ammonium fluoride in a 50 ml solution were dropped simultaneously. AlF ₃ was precipitated on the surface of the powder body.

Example 10
A phosphor was obtained in the same manner as in Example 1 except that 4.21 g of gadolinium chloride in a 50 ml solution and a solution in which 1.95 g of ammonium fluoride was made into a 50 ml solution were dropped simultaneously. GdF ₃ was precipitated on the surface of the powder body. GdF ₃ was 2.25 wt% relative to the powder body.

Example 11
A phosphor was obtained in the same manner as in Example 1 except that 2.35 g of calcium chloride dihydrate in a 50 ml solution and 1.43 g of ammonium fluoride in a 50 ml solution were dropped simultaneously. CaF ₂ was precipitated on the surface of the powder body. CaF ₂ was 0.68 wt% relative to the powder body.

Example 12
A phosphor was obtained in the same manner as in Example 1 except that a solution containing 3.95 g of lanthanum chloride in a 50 ml solution and a solution containing 1.95 g of ammonium fluoride in a 50 ml solution were dropped simultaneously. LaF ₃ was deposited on the surface of the powder body. LaF ₃ was 4.33 wt% relative to the powder body.

Example 13
A phosphor was obtained in the same manner as in Example 1 except that 3.12 g of yttrium chloride in a 50 ml solution and 1.95 g of ammonium fluoride in a 50 ml solution were dropped simultaneously. YF ₃ was precipitated on the surface of the powder body. YF ₃ was 2.80 wt% relative to the powder body.

Example 14
A phosphor was obtained in the same manner as in Example 1 except that 1.95 g of ammonium fluoride in a 50 ml solution was added dropwise. NH ₄ F was deposited on the surface of the powder body.

[Comparative Example 1]
A phosphor of only manganese-activated zinc silicate obtained by the method described above was obtained.

2. Evaluation of phosphors The phosphors obtained above were evaluated as follows.

(1) Ion bombardment luminance maintenance rate It measured using the 146nmKr excimer light irradiation apparatus (made by Ushio Electric) and the spectral radiance meter CS-1000 (made by Minolta).
The phosphor was baked at 500 ° C. for 1 hour. With respect to the phosphor after baking, the relative luminance at the time of 146 nm vacuum ultraviolet excitation was measured. Next, the phosphor after baking was irradiated with Ar ions for 9 minutes under the condition of 12.5 mA by E1030 Hitachi Ion Sputter (manufactured by Hitachi). With respect to the phosphor after irradiation with Ar ions, the relative luminance at the time of 146 nm vacuum ultraviolet excitation was measured. The obtained value of relative luminance after Ar ion irradiation was divided by the value of relative luminance after baking to obtain the ion bombardment luminance maintenance ratio.
In addition, the ion bombardment luminance maintenance rate of the example was calculated by setting the ion bombardment luminance maintenance rate of Comparative Example 1 to 100%.

(2) VUV luminance maintenance rate It measured using the 146nmKr excimer light irradiation apparatus (made by Ushio Electric) and the spectral radiance meter CS-1000 (made by Minolta).
The phosphor was baked at 500 ° C. for 1 hour. With respect to the phosphor after baking, the relative luminance at the time of 146 nm vacuum ultraviolet excitation was measured. Next, the phosphor after baking was irradiated with 146 nm vacuum ultraviolet rays for 21 hours. With respect to the phosphor after irradiation with vacuum ultraviolet rays, the relative luminance upon excitation with 146 nm vacuum ultraviolet rays was measured. The obtained relative luminance value after irradiation with vacuum ultraviolet rays was divided by the relative luminance value after baking to obtain the VUV luminance maintenance ratio.
Note that the VUV luminance maintenance ratio of the example was calculated by setting the VUV luminance maintenance ratio of Comparative Example 1 to 100%.

The results are shown in Table 1.
As is apparent from Table 1, it can be seen that the phosphor of the present invention is excellent in the ion bombardment luminance maintenance ratio and the VUV luminance maintenance ratio.

  The vacuum ultraviolet excitation phosphor of the present invention can be used for a PDP, a high load fluorescent lamp, a rare gas discharge lamp, and the like.

FIG. 1 is a cross-sectional view showing the phosphor of the present invention.

Explanation of symbols

11b, 11c Powder body 12, 12b, 12c, 12d, 12e Coating layer

Claims (11)

A vacuum ultraviolet-excited phosphor comprising a powder body and a powder having a coating layer covering at least a part of the surface of the powder body,
The powder body is manganese activated zinc silicate,
The coating layer is a vacuum ultraviolet excitation phosphor made of at least one selected from the group consisting of aluminum fluoride, gadolinium fluoride, lanthanum fluoride, yttrium fluoride, and ammonium fluoride. A vacuum ultraviolet-excited phosphor comprising a powder body and a powder having a coating layer covering at least a part of the surface of the powder body,
The powder body is manganese activated zinc silicate,
The coating layer is made of fluoride,
The amount of the fluoride is less than 1% by weight with respect to the powder body. The fluoride is at least one selected from the group consisting of magnesium fluoride, barium fluoride, lithium fluoride, aluminum fluoride, gadolinium fluoride, calcium fluoride, lanthanum fluoride, yttrium fluoride, and ammonium fluoride. The vacuum ultraviolet-excited phosphor according to claim 2. The vacuum ultraviolet-excited phosphor according to claim 1, wherein the coating layer forms a microcapsule. The vacuum ultraviolet-excited phosphor according to any one of 1 to 4, wherein the coating layer has a multilayer structure made of a plurality of different materials. The vacuum ultraviolet-excited phosphor according to claim 5, wherein the coating layer having the multilayer structure increases the refractive index on the powder body side and decreases the refractive index on the phosphor surface side. The powder body has at least one selected from the group consisting of magnesium, calcium, strontium, barium, tin, yttrium, lanthanum and europium, and at least one selected from the group consisting of germanium, gadolinium, gallium and sulfur. It is a manganese activated zinc silicate, The vacuum ultraviolet-excited fluorescent substance in any one of Claims 1-6. The said manganese activated zinc silicate is a vacuum ultraviolet-excited fluorescent substance in any one of Claims 1-7 in which manganese is activated 0.2 to 1.0 weight% with respect to zinc silicate. The powder body has the general formula ^{_{(Zn 1-a-b,}} M 1 a, Mn b) 2 (Si 1-c, M 2 c) O 4 (M 1 is magnesium, calcium, strontium, barium, tin, yttrium Represents at least one selected from the group consisting of lanthanum and europium, M ² represents at least one selected from the group consisting of germanium, gadolinium, gallium and sulfur, and a is a number satisfying 0 ≦ a ≦ 0.05 7 represents a number satisfying 0.005 ≦ b ≦ 0.2, and c represents a number satisfying 0 ≦ c ≦ 0.05. Vacuum ultraviolet excitation phosphor. The vacuum ultraviolet-excited phosphor according to any one of claims 1 to 9, wherein a specific surface area of the powder body is 1.0 to 8.0 µm. The plasma display panel using the vacuum ultraviolet-excited fluorescent substance in any one of Claims 1-10.

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