KR101771448B1 - Method for producing phosphor material, phosphor material and light emitting device - Google Patents

Abstract

A method of manufacturing a phosphor material capable of efficiently forming a coating layer on the surface of the phosphor particles and obtaining high characteristics and a high yield, a phosphor material obtained thereby, and a light emitting device using the phosphor material.
(Solution) A slurry containing the phosphor particles 11, the ceramic microparticles 12A and a liquid is prepared (step S101). Subsequently, the slurry is dried by a reduced pressure evaporation drying method to remove the liquid, and the ceramic fine particles 12A are attached to the surface of the phosphor particles 11 (step S102). Subsequently, after the slurry is dried, the phosphor particles 11 to which the ceramic fine particles 12A are adhered are heat-treated in an inert gas atmosphere (step S103).

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a phosphorescent material,

The present invention relates to a method for producing a phosphor material having a coating layer (coating layer) on the surface of phosphor particles (phosphor particles), a phosphor material obtained thereby, and a light emitting device using the phosphor material.

BACKGROUND ART Currently, LED lamps are attracting attention as a backlight of a liquid crystal television or a next-generation illumination. In order to emit the LED lamp as white light, it is necessary to obtain white light by overlapping the light emission from the LED element itself with the application of phosphor such as red / blue / green or through the mixed lens and luminescence from the phosphor. However, the phosphor has a weak point that when it is exposed to moisture, heat or ultraviolet rays, the luminescence characteristics are lowered. Therefore, deterioration of characteristics is prevented by covering the phosphor particles with ceramics, and the lifetime is prolonged (see, for example, Patent Document 1). There are a variety of coating methods, but it is preferable to coat ceramics fine particles (ceramics fine particles) as a raw material because high properties can be obtained. Specifically, for example, there is known a method in which phosphor particles, ceramics fine particles and liquid are mixed to form a slurry, and this is dried by spray drying, hot air drying or natural drying (see, for example, Patent Document 2) .

Patent Document 1: JP-A-2010-280877 Patent Document 2: JP-A-2008-291251

However, since spray drying or hot air drying requires drying of the liquid by mixing or flowing a large amount of gas and powder (powder) in the gas, the phosphor particles and the ceramic fine particles are also emitted from the path that discharges the conveyed gas There was a problem. In order to prevent this, studies have been made to reduce the loss by, for example, trapping the powder through a bag filter, but it is difficult to increase the yield even if this is done. In addition, even if the problem of the yield can be solved, particles of small particle diameters that can not be completely collected by the Bug filter are passed through the filter and released. Therefore, the particle size of the phosphor particles serving as the base material There has been a problem that the distribution is changed and a hindrance occurs in practice. In addition, most of the phosphor particles are very expensive, so even if a small amount of loss occurs, the damage becomes enormous. In addition, there is a problem that the ceramic fine particles may be dried without adhering to the phosphor particles.

On the other hand, in the case of natural drying, since the specific surface area in contact with the dry gas is significantly smaller than in spray drying or hot air drying, a long period of time is required for drying, and moisture in the atmosphere is adsorbed during drying, There is a problem that the particles are deteriorated. For example, as a method of controlling the atmosphere and drying in a dehydration atmosphere, a glove box or the like is used. However, since it is necessary to introduce dehydrated atmosphere gas while always exhausting it, it is not realistic because it takes a great deal of time and cost.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a method of manufacturing a phosphor material capable of efficiently forming a coating layer on the surface of the phosphor particles and achieving high characteristics and high yield, a phosphor material obtained thereby, And an object of the present invention is to provide a device.

A method for producing a phosphor material of the present invention is a method for manufacturing a phosphor material having a coating layer on the surface of phosphor particles and a slurry containing phosphor particles and fine particles of ceramics and a liquid is dried by a vacuum evaporation drying method Followed by drying to remove the liquid, thereby forming a coating layer on the surface of the phosphor particles.

The phosphor material of the present invention is produced by the method for producing the phosphor material of the present invention, and the light emitting device of the present invention includes the phosphor material produced thereby.

According to the method for producing the phosphor material of the present invention, since the slurry containing the phosphor particles, the ceramic fine particles and the liquid is dried by the reduced-pressure evaporation drying method, the amount of the exhaust gas is extremely small and the phosphor particles and the ceramic fine particles, It is possible to minimize the amount of the exhausted gas to the outside of the apparatus. Therefore, it is possible to increase the yield of the phosphor particles, to prevent the change of the particle size distribution of the phosphor particles, and to maintain the quality of the phosphor material. In addition, the amount of the ceramic fine particles that are not attached to the phosphor particles and dried alone can be reduced, and the film forming efficiency can be increased. In addition, since the drying time is short and can be efficiently produced, and the influence of moisture is small, characteristic deterioration can be prevented.

Further, when the slurry is dried and then heat-treated in an inert gas atmosphere, for example, in an inert gas atmosphere containing at least one species selected from the group consisting of nitrogen and Group 18 elements of the long-form periodic table, it is possible to prevent deterioration of the characteristics of the phosphor particles The adhesion can be enhanced.

Further, when the slurry is stirred when the slurry is dried, the drying time can be further shortened.

When the average particle size of the ceramic fine particles is set to 40 nm or less, or when the ceramic fine particles are composed of a complex oxide of a rare earth oxide, zirconium oxide, titanium oxide, zinc oxide, aluminum oxide, composite oxide of yttrium and aluminum, magnesium oxide and aluminum and magnesium It is possible to further improve the properties such as water resistance and ultraviolet ray resistance.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a flow chart showing the steps of a method of manufacturing a phosphor material according to an embodiment of the present invention.
2 is a schematic diagram showing the structure of a phosphor material produced by the method for producing a phosphor material according to one embodiment of the present invention.
3 is a view showing a configuration of a light-emitting device using a phosphor material produced by a method for producing a phosphor material according to an embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Fig. 1 shows a step of a method of manufacturing a phosphor material according to one embodiment of the present invention. Fig. 2 schematically shows a phosphor material 10 manufactured according to the method. The method for manufacturing the phosphor material 10 according to the present embodiment is a method for manufacturing the phosphor material 10 having the coating layer 12 on the surface of the phosphor particles 11, Is obtained by the method for producing the phosphor material 10.

In the method for producing the phosphor material 10, first, for example, a slurry containing the phosphor particles 11, the ceramic fine particles 12A and a liquid is prepared (step S101). Examples of the phosphor particles 11 include blue phosphor such as BaMgAl ₁₀ O ₁₇ : Eu, ZnS: Ag, Cl, BaAl ₂ S ₄ : Eu or CaMgSi ₂ O ₆ : Eu, Ca, Sr) ₂ SiO ₄ : Eu, Zn ₂ SiO ₄ : Mn, (Y, Gd) BO ₃ : Tb, ZnS: Cu, Al or (Ba, Sr, Mg) O.aAl ₂ O ₃ : Green phosphors, and red phosphors such as (Y, Gd) BO ₃ : Eu, Y ₂ O ₂ S: Eu or YPVO ₄ : Eu. Although the particle diameter of the phosphor particles 11 may be basically any, it is preferable that the average particle diameter is about 5 μm to about 20 μm and the particle diameter is as equal as possible. The characteristics can be stabilized.

The ceramic fine particles 12A are for forming the coating layer 12 and include a composite oxide of yttrium and aluminum such as rare earth oxide, zirconium oxide, titanium oxide, zinc oxide, aluminum oxide, yttrium aluminum, garnet , Magnesium oxide, and MgAl ₂ O ₄ , and a composite oxide of aluminum and magnesium, as the main component. Water resistance and ultraviolet ray characteristics can be improved. Of these, rare earth oxides are preferable, and rare earth oxides containing at least one element selected from the group consisting of yttrium, gadolinium, cerium and lanthanum are more preferable, and Y ₂ O ₃ is particularly preferable. This is because a higher effect can be obtained and cost can be suppressed. The ceramics fine particles 12A may be used singly or in combination of two or more kinds. The ceramic fine particles 12A made of one kind of metal oxide may be used, but the ceramic fine particles 12A containing two or more kinds of metal oxides may be used.

The average particle diameter of the ceramic fine particles 12A is preferably 40 nm or less, more preferably 30 nm or less, and further preferably 25 nm or less. This is because a small average particle diameter allows deposition of the ceramic fine particles 12A in a state in which the particles are easily attached to the phosphor particles 11 and the interval between the particles is extremely small, so that a good coating layer 12 can be formed. The average particle diameter of the ceramic fine particles 12A is preferably 10 nm or more, more preferably 15 nm or more. If the average particle diameter of the ceramic fine particles 12A is too small, rough secondary aggregated particles tend to be generated and it becomes difficult to uniformly coat the phosphor particles 11. [ The average particle diameter of the ceramic fine particles 12A is preferably 1/100 or less of the average particle diameter of the phosphor particles 11 to 1/500 or less. This is because the coating layer 12 can be formed more stably. The average particle diameter is the average particle diameter of the primary particles.

The maximum particle diameter of the ceramic fine particles 12A is preferably 50 nm or less, for example. If large particles are present, defects in which the phosphor particles 11 are exposed are liable to occur. The maximum particle diameter of the fine particles 12A is more preferably 40 nm or less, and more preferably 30 nm or less.

As the liquid for dispersing the ceramic fine particles 12A, for example, an organic solvent is preferably used. Basically, any liquid may be used. However, it is preferable to use ethanol or IPA (isopropyl alcohol) as a material which is inexpensive and easy to evaporate at normal temperature and pressure and low in toxicity. However, from the viewpoint of the influence on the phosphor particles 11 to be the base material, a material containing a large amount of water and water is not preferable. Also, materials which are difficult to evaporate at room temperature and normal pressure are also undesirable.

Subsequently, the slurry is dried by a reduced pressure evaporation drying method to remove the liquid, and the coating layer 12 is formed by attaching the ceramic fine particles 12A to the surface of the phosphor particles 11 (step S102). The reduced-pressure evaporative drying method is a method of promoting the evaporation of liquid by drying in a reduced-pressure atmosphere. Further, in order to promote drying, the slurry temperature may be raised by heating from the outside of the vessel. When the slurry is dried, it is preferable to stir (stir) the slurry. This is because the drying time can be shortened. When the slurry is heated from the outside, an effect of preventing the boiling of the slurry is obtained by stirring. The stirring may be carried out, for example, by rotating a container containing the slurry, or by a stirring device such as a rotating blade provided in a container for containing the slurry. Specifically, it is preferable to use, for example, a rotary evaporator or a flash evaporator.

It is preferable to heat treat the phosphor particles 11 having the ceramics fine particles 12A adhered thereto in an inert gas atmosphere (step S103). This is because adhesion of the coating layer 12 can be enhanced while deterioration of the characteristics of the phosphor particles 11 is prevented. The inert gas includes, for example, at least one species selected from the group consisting of nitrogen and Group 18 elements of the long periodic table (long-period periodic table 18 elements). The heat treatment temperature is preferably, for example, 450 DEG C or less. This is because deterioration of characteristics can be prevented.

Each step of preparing the slurry (step S101), drying (step S102), and heat treatment (step S103) may be performed once, but it may be repeated a plurality of times. For example, the slurry is prepared (step S101), dried (step S102), heat treated (step S103), and the slurry is coated on the phosphor particles 11 having the coating layer 12 formed thereon with the ceramic fine particles 12A and liquid (Step S101), drying (step S102), and performing heat treatment (step S103). This is because the phosphor particles 11 can be coated more reliably. When repeating a plurality of times, other kinds of ceramic fine particles 12A may be used for the slurry. The coating layer 12 is preferably laminated with three or more particle layers of the ceramic fine particles 12A in the thickness direction, and the thickness of the coating layer 12 is preferably 10 nm or more and 1 μm or less. If the number of layers of the ceramic fine particles 12A is small or if the thickness of the coating layer 12 is small, the effect of preventing characteristic deterioration is small. If the thickness is too large, the light transmittance is decreased and the luminous efficiency is lowered. Thus, the phosphor material 10 having the surface of the phosphor particles 11 covered with the coating layer 12 is obtained.

Fig. 3 shows a configuration example of the light emitting device 20 using the phosphor material 10. As shown in Fig. The light emitting device 20 has the light emitting element 22 mounted on the substrate 21 and the light emitting element 22 is electrically connected to the wiring 23 formed on the substrate 21 and the wire 24 Respectively. A reflector frame 25 is formed around the light emitting element 22 and a sealing layer 26 is formed on the light emitting element 22 to cover the light emitting element 22. [ The sealing layer 26 is made of, for example, a resin in which the phosphor material 10 is dispersed.

The light emitting element 22 is used to emit ultraviolet light, blue light or green light as excitation light, for example. As the phosphor material 10, for example, one type of generating red light by excited light emitted from the light emitting element 22, generating blue light, generating green light, generating yellow light, and the like Or two or more of them may be used in combination as required.

As described above, according to the present embodiment, since the slurry containing the phosphor particles 11, the ceramic fine particles 12A and the liquid is dried by the reduced-pressure evaporation drying method, the amount of exhaust gas is extremely small, And the amount of the ceramic fine particles 12A discharged to the outside of the processing apparatus can be extremely reduced. Therefore, it is possible to increase the yield of the phosphor particles 11, to prevent the change of the particle size distribution of the phosphor particles 11, and to maintain the quality of the phosphor material 10. In addition, the amount of the ceramic fine particles 12A that are not attached to the phosphor particles 11 and dried alone can be reduced, and the film forming efficiency can be increased. In addition, since the drying time is short, it can be efficiently produced, and the effect of moisture is small, so that deterioration of the characteristics can be prevented.

Further, when the slurry is dried and then heat-treated in an inert gas atmosphere, for example, in an atmosphere of an inert gas containing at least one species selected from the group consisting of nitrogen and elements of the Group 18 of the periodic table, the properties of the phosphor particles 11 are prevented from deteriorating The adhesion of the coating layer 12 can be enhanced.

Further, when the slurry is stirred when the slurry is dried, the drying time can be further shortened.

The average particle size of the ceramic fine particles 12A may be 40 nm or less or the ceramic fine particles may be mixed with a rare earth oxide, zirconium oxide, titanium oxide, zinc oxide, aluminum oxide, composite oxides of yttrium and aluminum, magnesium oxide, When at least one kind of metal oxide is included in the group consisting of oxides, properties such as water resistance and ultraviolet rays can be further improved.

[Example]

(Example 1)

The average particle size of 20nm, the maximum particle diameter of 50nm of yttrium oxide (Y ₂ O ₃₎ to mix the formed ceramic particles (12A) to which as an average particle size of the phosphor particles 11 of the green-based of about 10μm dispersed in an organic solvent To prepare a slurry (step S101). Subsequently, the slurry was dried by a reduced pressure evaporation drying method using a rotary evaporator to remove the organic solvent (step S102). At this time, the slurry was dried by stirring while rotating the container containing the slurry. Subsequently, the dried phosphor particles 11 having the ceramic fine particles 12A adhered thereto were heat-treated at 400 degrees for 2 hours in a nitrogen atmosphere (step S103). Subsequently, the slurry was prepared (step S101), dried (step S102) and heat treatment (step S103) were repeated once more for the obtained powder, that is, the phosphor particles 11 having the coating layer 12 formed thereon, A material (10) was obtained. The yield of the phosphor particles 11 used as a raw material in the obtained phosphor material 10 was 95% or more. The yield was determined by the yield = total weight after treatment / (weight of phosphor particles before treatment + weight of ceramics fine particles).

(Comparative Example 1-1)

A phosphor material was prepared in the same manner as in Example 1 except that the slurry was dried by spray drying. The yield of the phosphor particles used as a raw material for the obtained fluorescent material was examined and found to be about 70%.

(Comparative Example 1-2)

A phosphor material was prepared in the same manner as in Example 1 except that the slurry was dried by natural drying. In Comparative Example 1-2, it took 10 times or more time to dry the same amount of slurry as in Example 1, compared with Example 1.

Table 1 shows the results of Example 1 and Comparative Examples 1-1 and 1-2. The drying of the slurry by the reduced pressure evaporation drying method as described above is preferable because the yield of the phosphor particles 11 can be increased and the drying time can be shortened.

(Example 2-1)

Using the phosphor material 10 prepared in Example 1, a light emitting device 20 as shown in Fig. 3 was fabricated. The light emitting element 22 was made to emit ultraviolet rays.

(Example 2-2)

A phosphor material 10 was produced in the same manner as in Example 1 except that the heat treatment was performed in an oxidizing atmosphere (in the atmosphere), and the light emitting device 20 was fabricated in the same manner as in Example 2-1.

(Comparative Example 2)

A light-emitting device was fabricated in the same manner as in Example 2-1, except that a coating layer was not formed on the phosphor particles and used as a phosphor material as it was.

(Deterioration test)

Each of the light emitting devices 20 of Examples 2-1 and 2-2 and Comparative Example 2 was subjected to a light emission test to examine changes in luminance with time. The obtained results are shown in Table 2. In Table 2, the relative luminance is a relative value when the initial luminance of Comparative Example 2 in which the coating layer is not formed is 100%.

It was found that when the slurry was dried and then heat-treated in an inert gas atmosphere as described above, the initial luminance and the luminance retention could be greatly improved. It was also found that when the heat treatment is performed in an atmospheric atmosphere, the initial luminance is lowered, but the luminance retention ratio can be improved as compared with the untreated Comparative Example 2. [

(Examples 3-1 to 3-5)

The phosphor material 10 was produced in the same manner as in Example 1 except that the average particle diameter and the maximum particle diameter of the ceramic fine particles 12A were changed and the light emitting device 20 was fabricated in the same manner as in Example 2-1, Respectively. In Example 3-1, the average particle diameter was 40 nm, the maximum particle diameter was 50 nm, the average particle diameter in Example 3-2 was 30 nm, the maximum particle diameter was 50 nm, the average particle diameter in Example 3-3 was 25 nm, The ceramic fine particles 12A having a diameter of 50 nm, an average particle diameter of 20 nm and a maximum particle diameter of 40 nm in Example 3-4, an average particle diameter of 15 nm and a maximum particle diameter of 40 nm in Example 3-5 were used. The obtained light emitting device 20 was subjected to a light emission test in the same manner as in Example 2-1, and the change in luminance with time was examined. The obtained results are shown in Table 3 together with the results of Example 2-1 and Comparative Example 2. In Table 3, the luminance retention ratio after 2000 hours is a relative value when the initial luminance of Comparative Example 2 in which the coating layer is not formed is 100%.

It was found that when the average particle diameter of the ceramic fine particles 12A was 40 nm or less and 10 nm or more, high characteristics were obtained. It was also found that when the maximum particle diameter of the fine particles 12A is 50 nm or less, higher characteristics can be obtained.

While the present invention has been described with reference to the embodiment thereof, it is to be understood that the invention is not limited to the above-described embodiment but may be modified in various ways. For example, in each of the above embodiments, the manufacturing process of the phosphor material 10 has been described. However, the manufacturing process may not include all processes or may include other processes.

[Industrial applicability]

And can be used for light emitting devices such as LEDs.

10 ... Phosphor material
11 ... Phosphor particles
12 ... Coating layer
12A ... Ceramics fine particles
20 ... Light emitting device
21 ... Board
22 ... Light emitting element
23 ... Wiring
24 ... wire
25 ... Reflector frame
26 ... Sealing layer

Claims (9)

A method for producing a phosphor material comprising a coating layer (coating layer) on the surface of phosphor particles (phosphor particles)
A step of forming a coating layer on the surface of the phosphor particles by drying the slurry containing the phosphor particles, the ceramics fine particles and the liquid by a reduced pressure evaporation drying method to remove the liquid ,
After drying the slurry, the slurry is subjected to heat treatment in an inert gas atmosphere (inert gas atmosphere) containing at least one of the group consisting of nitrogen and Group 18 elements of the long periodic table (Group 18 elements of the long periodic table) Process
The method of manufacturing a phosphor material according to claim 1,
delete delete The method according to claim 1,
And the slurry is stirred (stirred) when the slurry is dried.
The method according to claim 1,
Characterized in that a rotary evaporator or a flash evaporator is used to dry the slurry.
The method according to claim 1,
Wherein the average particle diameter of the ceramic fine particles is 40 nm or less.
The method according to claim 1,
The ceramic fine particles may be at least one selected from the group consisting of rare earth oxides (rare earth oxides), zirconium oxide, titanium oxide, zinc oxide, aluminum oxide, composite oxides of yttrium and aluminum, magnesium oxide and composite oxides of aluminum and magnesium Characterized in that the phosphor material comprises a metal oxide of the species.
As a phosphor material having a coating layer on the surface of the phosphor particles,
A slurry containing phosphor particles, ceramics fine particles and a liquid is dried by a reduced-pressure evaporation drying method to remove the liquid to form a coating layer on the surface of the phosphor particles , and then at least one member selected from the group consisting of nitrogen and elements of Group 18 of the long- In an atmosphere of an inert gas containing boron .
A light emitting device comprising a phosphor material,
The phosphor material includes a coating layer provided on the surface of the phosphor particles, a slurry containing the phosphor particles, the ceramic fine particles and the liquid is dried by a reduced pressure evaporation drying method to remove the liquid to form a coating layer on the surface of the phosphor particles, And at least one group selected from the group consisting of Group 18 elements of the long periodic table.
And a light emitting device.

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