JPH0940945A - Phosphor and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a phosphor by adhering small particles of a pigment and/or small particles for surface modification to the surface of a phosphor in such a manner that the small particles are prevented from agglomerating among them and are adhered to the phosphor with strong adhesive force, and to provide a process for producing the same. SOLUTION: This phosphor is prepared by a process comprising mixing phosphor particles and a heat-softening binder together with a solvent, adding small particles of a pigment and small particles for surface modification to the mixture and mixing the entire mixture, which process comprises adjusting the amount of the small particles added so that a single layer of the small particles may cover the surface of a phosphor particle, removing the solvent from the mixture, softening the heat-softening binder by heating to unite with the surface of a phosphor particle and forming the single layer of the small particles on the surface and a process for producing the same is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phosphor for use as a display device which emits light by electron beams, X-rays, ultraviolet rays and the like, and a method for manufacturing the same, and particularly to forming a phosphor film by a slurry coating method. Related to suitable phosphors.

[0002]

2. Description of the Related Art Conventionally, a phosphor used as a phosphor film of a display device such as a color cathode ray tube, a fluorescent display tube, a plasma display or an EL display has its surface coated with pigment particles or inorganic compound powder particles. The surface modification treatment of phosphors is widely performed.

For example, in order to sharpen the emission spectrum of the phosphor to improve the color purity and to absorb the reflection of external light on the phosphor screen to improve the contrast of the image, a coloring filter material is provided on the surface of the phosphor particles. Pigment-attached phosphors to be attached are known. The pigment-adhered phosphor is usually prepared by adhering pigment particles having an average particle size of about 0.005 to 0.3 μm on the phosphor surface using a binder such as acrylic emulsion, gelatin, casein, gum arabic, and polyacrylate. It is fixed.

For example, Japanese Patent Application Laid-Open No. 63-284290 describes a method of using a water-soluble binder such as casein, mixing it with pigment particles and a phosphor, and adhering the pigment to the surface of the phosphor. However, since the binder is present on the entire surface of the pigment particles when the pigment is attached, the pigment particles agglomerate with each other and the phosphor particles agglomerate with each other, which deteriorates the filter characteristics (especially the contrast) of the phosphor. was there.

Further, Japanese Patent Laid-Open No. 59-149981,
Further, Japanese Patent Laid-Open No. 62-101685 proposes to modify the surface of the phosphor by attaching small inorganic particles such as oxides of Al and Ti or hydroxides to the surface of the phosphor. However, the method of directly precipitating / precipitating these powders on the surface of the phosphor is compared with the case where a single-particle powder such as alumina sol or titania sol whose particle size has been adjusted in advance is attached to a single layer. Since the powder adhered on the surface of the phosphor becomes non-uniform and the particle size distribution of the obtained phosphor is wide, the film forming property of the phosphor film (filling degree of the phosphor film, etc.) is poor and the emission brightness of the phosphor is low. There was a drawback that it was difficult to obtain enough.

Further, in JP-A-62-16881 and JP-A-63-199787, Zr, Ti,
A method has been proposed in which a sol of an oxide such as Hf, Ge, Si, Al, Y, La, and Sc is attached using a binder such as gelatin or gum arabic, but a phosphor is made into a slurry to form a film. At the stage, the above-mentioned oxide once attached to the surface of the phosphor is easily peeled off, and there is a defect that the film forming stability is poor.

Furthermore, in recent years, with the increase in the screen size of display devices, in order to meet the demands for maintaining desired contrast and further improving the emission brightness, and further improving the characteristics of the phosphor film, the surface of the phosphor is improved. Filter particles (pigment particles such as blue pigments, red pigments, green pigments, black pigments) attached to the surface and small particle powders for surface modification (silica, titania, alumina, indium oxide, zinc hydroxide and other inorganic compound powders) ) By reducing the particle size of the
It is conceivable to reduce the absorption of the light emission of the phosphor on the phosphor surface.

However, if the particle size of the small particle powder adhered to the surface of the phosphor is made smaller than that of the conventional one and the surface coverage is improved with a small amount of adhesion, the conventional method is In the adhesion treatment step, there is a problem that the agglomeration of the small particle powder is remarkable and the adhesive force of the small particle powder is weakened, so that the surface modification effect of adhering the small particle powder cannot be sufficiently obtained. It was

[0009]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above circumstances, and when the small pigment particles and / or the small particles for surface modification are attached to the surface of the phosphor, the small particles are mixed with each other. The present invention is intended to provide a phosphor in which the small particles are adhered to the phosphor with strong adhesion to the phosphor and a method for producing the phosphor.

[0010]

Means for Solving the Problems When the present inventors attach small particles of a coloring pigment such as cobalt blue and red polka dots or small particles for surface modification to the surface of a phosphor, the present inventors In order to suppress agglomeration and to strengthen the adhesive force of the small particles, as a result of diligent examination of the binder type, the adhesion method, etc., a phosphor softener binder was previously adhered to the phosphor particle surface, By further adsorbing small amounts of pigment small particles and / or small particles for surface modification onto the surface of the binder, the binder is heated and softened to firmly fix the particles. Completed the invention.

According to the present invention, since the thermosoftening binder hardly remains on the outer surface (exposed surface) of the small particles adhered to the phosphor, when the phosphor film is produced using this binder. As a result, it is possible to further enhance the filling property of the obtained phosphor film without aggregating the phosphors, and to improve the emission brightness of the phosphor film. That is, the solving means of the present invention is as follows.

(1) Thermosoftening binder on the surface of phosphor particles
A phosphor comprising a single layer of small particles which are made into single particles through a layer.

(2) Thermosoftening binder on the surface of phosphor particles
Pigment small particles made into single particles through a layer are attached in a single layer,
A phosphor having a plurality of layers formed by further adhering small particles, which have been made into single particles, through a thermosoftening binder layer in a single layer thereon.

(3) The small particles are small pigment particles and / or oxides or hydroxides of one or more elements selected from Si, Al, Zr, Ti, Zn, In and Sn, The phosphor according to (1) or (2) above, which is a small particle selected from carbides and nitrides.

(4) The average particle size of the small particles is 1 to 100.
The phosphor according to any one of (1) to (3) above, which is in the range of mμ.

(5) The heat-softening binder is at least one organic binder selected from the group consisting of styrene, butadiene and acrylic binders.
The phosphor according to any one of (4).

(6) The phosphor particles and the heat-softening binder are mixed with a solvent, and then the small particles are added and mixed, in which case the addition amount of the small particles covers the surface of the phosphor particles with a single layer. The amount is adjusted to a desired amount, then the solvent is removed, and the thermosoftening binder is heated and softened to form a single layer of the small particles in a substantially single particle state on the phosphor particle surface. The method for producing a phosphor according to any one of (1) and (3) to (5) above.

(7) The phosphor particles and the thermosoftening binder are mixed with a solvent, and then the small particles are added and mixed, in which case the addition amount of the small particles covers the surface of the phosphor particles with a single layer. The amount is adjusted, then the solvent is removed, and the thermosoftening binder is heated and softened to form a monolayer of the small particles in the state of almost monoparticles on the phosphor particle surface, and then, Any one of (1) to (5) above, characterized in that the step of forming a single layer of small particles is repeated for a phosphor having a single layer of small particles to form a plurality of layers of the small particles.
The method for producing the phosphor according to item 1.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The thermosoftening binder of the present invention is
It can be selected from water-soluble binders, oil-soluble binders, and water-dispersed emulsions, but when applied to a phosphor for a color CRT, an organic compound and / or an organic compound that is thermally decomposed and vaporized at 500 ° C. or lower. It is especially desirable to be an inorganic compound. From the viewpoint of adjusting acid resistance, alkali resistance, and thermal softening property, an organic binder containing at least one of styrene, butadiene, and acrylic is preferable, and more preferably at a relatively low temperature. It is preferable to use an acrylic / styrene-based or styrene-butadiene-based binder that is softened and has a good thermal decomposition vaporization property. Particularly preferably, acrylic / styrene binder (acryl / styrene composition ratio = 30 to 50/70)
˜50, particle size = 50 to 100 μm).

As the pigment particles used in the present invention, red pigment particles, green pigment particles, blue pigment particles, yellow pigment particles, black pigment particles, white pigment particles and the like are used according to the emission color of the phosphor. Specifically, inorganic red pigment particles such as red iron oxide, inorganic blue pigment particles such as cobalt blue, T
_{iO 2 -CoO-Al 2 O 2} -Li 2 O -based oxide pigment particles such as inorganic green pigment particles of the green pigments and the like are used.

In the phosphor of the present invention, the small particles attached to the surface of the phosphor for surface modification include Si and A.
l, Zr, Ti, Zn, Ba, Ca, Sr, Nd, T
m, Os, Y, In, Bi, Co, Hf, Tl, Ga,
One selected from oxides, hydroxides, carbides and nitrides of one or more elements selected from Mn, Ni, Sc, Cr, Fe, Sn, Nb, V, P and Mo. The above substances are used.

Among the above-mentioned elements, Si, Al, Zr, Ti, Y, and the like can be used as small particles for adjusting the charge on the surface of the fluorescent substance for fluorescent lamps and reducing the deterioration of the emission luminance with time.
Hf, P, etc. are used.

Among the above elements, In, Zn, Sn and the like are used as the small particles for imparting electric conductivity to the surface of the phosphor and using it as a phosphor for low speed electron beam. Further, among the above-mentioned elements, Si, Al, Zr, Ti, Zn, etc. are used as small particles for improving the characteristics of a fluorescent film such as a color cathode ray tube and increasing the filling degree of the fluorescent material in the fluorescent film. .

The average particle size of the small particles used in the present invention is
From the surface of adhesion, it is in the range of 1 to 100 mμ, especially 50 to 10
It is preferably in the range of 0 mμ. Average particle size is 100
When the average particle size is smaller than 1 mμ, when the average particle size is smaller than 1 mμ, the thermosoftening binder present on the surface of the phosphor covers the entire small particle powder, so that when the fluorescent film is formed, This is not preferable because it causes aggregation of the phosphors. The maximum particle size of the small particle powder is 150 m.
If it is larger than μ, the adhesion will deteriorate, so 150 mμ
The following is preferred.

The phosphor used in the present invention is not particularly limited, but Y ₂ O ₃ , (Y, Gd) ₂ O ₃ and Gd _{2 are used.}
O ₃ , Y ₂ O ₂ S, (Y, Gd) ₂ O ₂ S, La ₂ O ₂
Rare earth phosphors having S or the like as a host, ZnS, (Zn, C
d) a sulfide-based phosphor having S, CdS or the like as a matrix, (L
n, Ce, Tb) PO ₄ (where Ln is La, Y, Gd
And at least one of Lu), (Ca, Sr)
₅ (PO ₄ ) ₃ Cl: Eu, BaMg ₂ Al ₇ O ₂₇ : E
u, Ca ₂ B ₅ O ₉ Cl: Eu, (Ce, Tb) MgA
l ₁₁ O ₁₉ , Y ₂ SiO ₅ : Tb, Ce, MgO · B ₂ O
₃ : Including fluorescent materials for lamps such as Ce and Tb, electron beam,
Any phosphor can be applied as long as it is a phosphor that emits light by X-rays, ultraviolet rays, vacuum ultraviolet rays, or the like.

The method for producing the phosphor of the present invention will be described in detail below. Step of mixing phosphor and thermosoftening binder together with solvent: First, phosphor and solvent are mixed, and thermosoftening binder is added thereto and mixed sufficiently. As the solvent, water and / or organic solvent is used, and in order to improve the dispersibility of the phosphor, an inorganic and / or organic dispersion aid such as Si, P-based compound or anionic surfactant is further added. You may. Further, when an aqueous solvent is used, in order to improve the adsorptivity between the phosphor and the thermosoftening binder, a small amount of an acid such as sulfuric acid, acetic acid or citric acid, or an alkali such as caustic soda or ammonia is further added. May be added. The amount of the heat-softening binder used is appropriately in the range of 0.01 to 0.2% by weight / layer. In addition, since the stirring torque changes depending on the mixing ratio of the phosphor and the solvent, the stirring and fluidizing method during mixing is a relatively low power stirring and mixing apparatus in which the amount of the solvent added is equal to or higher than the limit solvent ratio (plasticity limit). It is preferable to select and mix.

Step of admixing small particles and adsorbing on the phosphor surface: Next, pigment small particles and other surface-modifying small particles are added to the mixture containing the phosphor obtained in the above step, the thermosoftening binder and the solvent. Is added and mixed well, and small particles are adsorbed on the surface of the phosphor particles through a heat-softening binder. The amount of small particles added at this time is based on the particle size and weight of the phosphor,
The amount of the added small particles covering the surface of the phosphor with almost one layer is calculated in advance, and the amount is weighed and added and mixed.

Step of removing the solvent in the mixture: In order to remove the solvent from the mixture (paste or slurry) in which the small particles are adsorbed on the surface of the phosphor particles via the thermosoftening binder, the solvent is removed from the mixture by a predetermined amount. Heat at the temperature. The heating temperature is preferably a temperature equal to or lower than the softening temperature of the thermosoftening binder. At this time, the exposed surface of the small particles adsorbed to the phosphor particles, since the heat-softening binder is hardly attached, there is almost no fear that the phosphors will be agglomerated by the binder during the heating, so the purpose is to prevent agglomeration. Strong stirring during heating is not particularly required.

The heating temperature for removing the solvent is set in accordance with the thermal softening property of the binder in order to prevent the binder existing on the surface of the phosphor from being melted to cause aggregation of the phosphors. It is preferable.

Step of adhering / fixing small particle powder of thermosoftening binder by heating: Next, the mixture from which the solvent in the mixture is removed in the above step is subjected to a predetermined temperature above the softening temperature of the thermosoftening binder. Heat to temperature and stir / flow the mixture. Depending on the temperature setting and the conditions of fluidized stirring at this time, the mixture extremely exceeds the softening temperature of the thermosoftening binder during fluidized stirring, and the binder at the interface between the phosphor and the small particles reaches the exposed surface of the small particles. Since there is a risk that they will move and cause the aggregation of the fluorescent substances, it is necessary to carefully consider the setting.

Through the above steps, a single layer of small pigment particles is formed on the surface of the phosphor particles through a layer of a thermosoftening binder, and / or
Or Si, Al, Zr, Ti, Zn, Ba, Ca, S
r, Nd, Tm, Os, Y, In, Bi, Co, Hf,
Tl, Ga, Mn, Ni, Sc, Cr, Fe, Sn, N
A state in which one or more small particles selected from oxides, hydroxides, carbides and nitrides of one or more elements selected from b, V, P and Mo are made into almost single particles. The phosphor of the present invention can be obtained by adhering to a single layer with. The present invention includes the case where a mixture of small pigment particles and the above surface-modified small particles is attached to a single layer.

Further, in the present invention, by repeatedly applying the above method, a single layer of almost single particles is laminated on the surface of the phosphor particles through the thermosoftening binder layer. It is also possible to form multiple layers.

The phosphor of the present invention thus obtained can be used by appropriately blending it with a phosphor to which small particles are not adhered, in order to obtain a phosphor film for a display tube with higher definition.

[0034]

EXAMPLES The present invention will be described in detail below with reference to examples of phosphors for color cathode ray tubes and phosphors for fluorescent lamps, but the present invention is not limited to these examples. [Example 1] 1000 g of blue light emitting phosphor (ZnS: Ag, Al) for color cathode ray tube having an average particle diameter of 7.5 μm
On the other hand, as a binder, an acrylic / styrene-based emulsion having an additive concentration of 0.1% by weight with respect to the blue light-emitting phosphor was used, and B-336 manufactured by Nippon Acrylic Co. ) Was diluted with 30 g of water, and added and mixed.

Next, in the mixture of the phosphor and the binder, the maximum particle size of the blue pigment was 0.15 μm or less, and the average particle size in the dispersed slurry state was 0.05 μm.
m cobalt blu was dispersed in water to form a slurry, and 1 wt% of cobalt blu corresponding to the blue-emitting phosphor was added and mixed in an amount of pigment slurry.
The amount required for adhering the pigment small particles, which are substantially mono-particles, to the mono-layer on the surface of the phosphor is about 1.0 wt%.

Then, after heating and drying at 100 ° C. to remove water, the phosphor layer is fluidized by stirring the phosphor layer at 120 ° C. to soften the binder to adsorb the pigment to the phosphor, and then cooled. Thus, a pigment-attached blue light-emitting phosphor having 1% by weight of cobalt bull-pigment attached was obtained.

[Comparative Example 1] A blue light emitting phosphor for a color cathode ray tube (ZnS: Ag, A) having an average particle diameter of 7.5 μm.
l) 1000 g, an acrylic / styrene emulsion with the addition concentration of 0.1% by weight to the blue-emitting phosphor (same as in Example 1), a maximum particle diameter of 0.15 μm, and an average particle diameter in a dispersed slurry state. Cobalt blue-blue pigment having a particle size of 0.05 μm was dispersed in water at a concentration of 1% by weight with respect to the blue-emitting phosphor and mixed sufficiently.

Then, the slurry containing the phosphor, the binder and the blue pigment is heated and dried at 120 ° C. to remove water, and the phosphor layer is fluidized by stirring the phosphor layer at the same temperature to soften the binder. After adsorbing the pigment on the phosphor, the phosphor was cooled to obtain a pigment-attached blue light-emitting phosphor on which 1% by weight of cobalt bull-pigment was attached. Since the phosphor, the binder, and the blue pigment were simultaneously added to this phosphor, the pigments coagulated and adhered to each other, and could not adhere to the single layer.

COMPARATIVE EXAMPLE 2 The procedure of Example 1 was repeated except that cobalt cobalt-pigment having an average particle diameter of 0.2 μm was used instead of 0.05 μm. A pigmented blue emitting phosphor with a wt% cobalt bull-pigment attached was obtained. The average particle size is 0.2
Approximately 10% by weight is required to deposit a μm pigment on a monolayer
Therefore, the adhesion amount was insufficient and a single layer could not be formed.

Example 2 The procedure of Example 1 was repeated except that the cobalt blue-pigment-attached blue light emitting phosphor obtained in Example 1 was used instead of the blue light emitting phosphor (ZnS: Ag, Al). In the same manner as in Example 1, 2% by weight of cobalt bull-pigment was deposited to obtain a blue light emitting phosphor having two small pigment particle layers (1% by weight per layer). It should be noted that the amount required to attach the small pigment particles, which are made into almost single particles, to the surface of the phosphor in a single layer in the first layer is about 1.0% by weight, and is attached in a single layer in the second layer. The required amount is about 2.0% by weight.

[Comparative Example 3] In Comparative Example 1, the addition amounts of the acrylic / styrene-based binder (same as in Example 1) and the cobalt bull-blue pigment were twice the amounts used in Comparative Example 1, respectively. 2% by weight of a pigment-attached blue light emitting phosphor was obtained in the same manner as in Comparative Example 1 except for the above. Since the phosphor, the binder, and the blue pigment were simultaneously added to this phosphor, the pigments coagulated and adhered to each other, and could not adhere to the single layer.

Example 3 Example 3 was repeated except that the cobalt blue-pigment-attached blue light emitting phosphor obtained in Example 2 was used in place of the blue light emitting phosphor (ZnS: Ag, Al) in Example 1. 3% by weight cobalt cobalt in the same manner as 1.
A blue light-emitting phosphor having three small pigment particle layers (1% by weight per one layer) was obtained by adhering the pigment. It should be noted that the amount of the small pigment particles, which are made into almost single particles, attached to the surface of the phosphor is approximately 1.0% by weight in order to be attached to the first layer in a single layer, and attached to the third layer in a single layer. The required amount is about 3.0% by weight.

[Comparative Example 4] Comparative Example 4 except that the amounts of the acrylic / styrene-based binder (same as in Example 1) and cobalt blue blue pigment added were 3 times the amounts used in Comparative Example 1, respectively. In the same manner as in Example 1, a 3% by weight pigment-attached blue light-emitting phosphor was obtained.

(Evaluation of Pigment Adhesion) The pigment adhesion of the phosphors of Examples 1 to 3 and Comparative Examples 1 to 4 was measured, and the results are shown in Table 1. The pigment adhesion was measured by placing 3.0 g of the above phosphor in a test tube, adding 0.1% water glass solution to a total volume of 30 ml, shaking the mixture for 1 minute, and then allowing it to stand for 1 hour with a spectrophotometer. Was used to irradiate the supernatant with light having a wavelength of 600 nm, and the transmittance (%) was measured and evaluated.
The larger the value of the transmittance, the smaller the degree of pigment peeling of the sample phosphor, and the stronger the adhesive force of the pigment. As is clear from Table 1, each of the phosphors of Examples has a larger pigment adhesion force than the conventional phosphors having the same pigment adhesion amount.

[0045]

[Table 1]

(Evaluation of Pigment Dispersion State) The pigment-attached blue light-emitting phosphors of Examples 1 to 3 and Comparative Examples 1 to 4 were photographed 10,000 times with a scanning electron microscope (SEM). As a result of observing the dispersion state of the pigment attached to the surface of the phosphor, the pigment-attached phosphors of Examples 1 to 3 were compared to Comparative Example 1 to
Unlike the pigmented phosphor of No. 4, the pigment particles were uniformly attached to the surface of the phosphor. 1 to 4 show Example 1,
5 is a scanning electron microscope (SEM) photograph showing the particle structures on the phosphor surfaces of Comparative Example 1, Example 3, and Comparative Example 3.

Example 4 With respect to 1000 g of a red light emitting phosphor for a lamp (Y ₂ O ₂ : Eu) having an average particle diameter of 3.5 μm, the concentration added to the red light emitting phosphor was 0.2% by weight.
The acrylic-styrene emulsion binder (RX-291 manufactured by Nippon Carbide Co., acrylic / styrene composition ratio = 50/50, particle diameter 0.1 μm) was diluted with 60 g of water, added, and mixed sufficiently.

Next, a slurry in which alumina sol having an average particle size of 10 mμ is dispersed in water in a mixture of the phosphor and the binder is used for adjusting the surface charge, and the slurry is 0 for the red light-emitting phosphor. The slurry containing alumina sol in an amount of 0.2% by weight was added and mixed.

Then, after heating and drying at 90 ° C. to remove water, the phosphor layer is further fluidized by stirring the phosphor layer at the same temperature to soften the binder and to adsorb the alumina sol to the phosphor. After cooling, a red-emitting phosphor having 0.2 wt% of alumina sol attached was obtained.

Comparative Example 5 An alumina sol-attached red light-emitting phosphor was obtained in the same manner as in Example 4, except that the step of adding the acrylic / styrene emulsion binder was omitted.

(Brightness Degradation Rate Test) The phosphors obtained in Example 4 and Comparative Example 5 described above were sieved to obtain a tube diameter 2
It is coated on the inner surface of a 0 mm glass tube, baked at 500 ° C. to form a phosphor layer, and filled with Ar gas.
A red fluorescent lamp was produced. The obtained fluorescent lamp uses an integrating sphere to determine the initial luminous flux and the luminous flux after 100 hours of lighting, and the results are shown in Table 1 together with the deterioration rate (the luminous flux after 100 hours of lighting with respect to the initial luminous flux as a percentage). . As can be seen from Table 2, the fluorescent lamp using the alumina sol-adhering phosphor of the present invention (Example 4) is 1% less than the conventional fluorescent lamp using the alumina sol-adhering phosphor (Comparative Example 5).
The deterioration rate of the luminous flux with time after 00 hours was improved.

[0052]

[Table 2]

[0053]

According to the present invention, by adopting the above-mentioned constitution, the small pigment particles and / or the small particles for surface modification can be uniformly adhered to the surface of the phosphor with a stronger adhesive force,
Moreover, since the phosphors after adhesion do not aggregate, when forming a phosphor film of a display device using this, a phosphor film having a high packing density can be obtained, and the emission brightness and other properties of the phosphor film can be further improved. I was able to.

[Brief description of drawings]

FIG. 1 is a scanning electron micrograph showing a particle structure on the surface of a phosphor of Example 1.

2 is a scanning electron micrograph showing the particle structure on the surface of the phosphor of Comparative Example 1. FIG.

3 is a scanning electron micrograph showing the particle structure on the surface of the phosphor of Example 3. FIG.

4 is a scanning electron micrograph showing the particle structure on the surface of the phosphor of Comparative Example 3. FIG.

Claims (7)

[Claims] 1. A phosphor comprising a single layer of small particles which have been made into single particles through a thermosoftening binder layer on the surface of the phosphor particles. 2. Small particles of a pigment, which have been made into single particles through a thermosoftening binder layer, are attached to the surface of phosphor particles in a single layer, and then the single particles are again provided through a thermosoftening binder layer. A phosphor, comprising a plurality of layers formed by adhering small particles that have been converted into a single layer. 3. The small particles are pigment small particles and / or
Small particles selected from oxides, hydroxides, carbides and nitrides of one or more elements selected from Si, Al, Zr, Ti, Zn, In and Sn. The phosphor according to claim 1 or 2. 4. The average particle diameter of the small particles is 1 to 100 m.
It is in the range of (micro | micron | mu), The fluorescent substance of any one of Claims 1-3 characterized by the above-mentioned. 5. The thermosoftening binder is at least one organic binder selected from the group consisting of styrene, butadiene and acrylic.
4. The phosphor according to any one of 4 above. 6. The phosphor particles and the thermosoftening binder are mixed with a solvent, and then the small particles are added and mixed.
The addition amount of the small particles is adjusted to an amount that coats the phosphor particle surface with a single layer, then, the solvent is removed, and the thermosoftening binder is heated and softened to almost single particles on the phosphor particle surface. The method for producing a phosphor according to any one of claims 1 and 3 to 5, wherein a single layer of the small particles is formed in a converted state. 7. The phosphor particles and the thermosoftening binder are mixed with a solvent, and then the small particles are added and mixed.
The addition amount of the small particles is adjusted to an amount that coats the phosphor particle surface with a single layer, then, the solvent is removed, and the thermosoftening binder is heated and softened to almost single particles on the phosphor particle surface. Forming a monolayer of said small particles in the liquefied state, then
The single layer formation process of the said small particle is repeated with respect to the fluorescent substance which has this small particle single layer, and the multiple layer of the said small particle is formed, The any one of Claims 2-5 characterized by the above-mentioned. The method for producing the phosphor of claim 1.