WO2015011925A1

WO2015011925A1 - Led device production method

Info

Publication number: WO2015011925A1
Application number: PCT/JP2014/003891
Authority: WO
Inventors: 小嶋　健
Original assignee: コニカミノルタ株式会社
Priority date: 2013-07-24
Filing date: 2014-07-24
Publication date: 2015-01-29
Also published as: JPWO2015011925A1

Abstract

An objective of the present invention is to provide a production method for an LED device having a satisfactory light extraction efficiency over a long period. To achieve the above objective, a production method for an LED device containing a substrate, an LED element disposed on the substrate, a metal part disposed on the substrate, and a wavelength conversion layer covering the LED element and the metal part, comprises preparing an LED package having an LED element and a metal part disposed on a substrate, applying and solidifying a phosphor dispersion solution containing a phosphor, a non-conducting layer-shaped clay compound, inorganic oxide microparticles and a solvent so as to cover the LED element and the metal part of the LED package and form a wavelength conversion layer; the non-conducting layer-shaped clay compound being such a compound that an aqueous solution with a concentration of 2% by mass for the non-conducting layer-shaped clay compound has a conductivity of 500 μS/cm or lower.

Description

Manufacturing method of LED device

The present invention relates to a method for manufacturing an LED device.

In recent years, phosphors such as YAG phosphors have been placed in the vicinity of gallium nitride (GaN) -based blue LED (Light Emitting Diode) chips to receive blue light and blue light emitted from the blue LED elements. An LED device that obtains white light by mixing yellow light emitted from a phosphor has been developed. Also, an LED device that obtains white light by arranging various phosphors in the vicinity of a blue LED element and mixing blue light emitted from the blue LED element with red light and green light emitted from the phosphor upon receiving blue light. Has also been developed.

White LED devices are widely applied to various lighting devices; in order to reduce the cost of lighting devices, there is a demand for improved light extraction efficiency from LED devices and longer life of LED devices. Thus, for example, it has been studied to provide a metal reflective layer on the substrate and in the vicinity of the LED element (Patent Document 1). According to this method, the emitted light from the LED element is efficiently reflected to the light extraction surface side.

On the other hand,

Patent Documents

2 and 3 propose that the LED element is covered with a wavelength conversion layer in which a phosphor is dispersed in ceramic. In these techniques, a wavelength conversion layer is formed by applying a phosphor dispersion in which a phosphor is dispersed in a solvent. In such a phosphor dispersion, a phosphor having a high specific gravity tends to settle. Therefore, in this technique, a swellable clay compound such as smectite is dispersed in the phosphor dispersion liquid to increase the viscosity of the phosphor dispersion liquid and enhance the dispersion stability of the phosphor.

JP 2005-136379 A International Publication No. 2011/129320 International Publication No. 2012/023425

In the techniques of

Patent Documents

2 and 3 described above, if the wavelength conversion layer contains a large amount of binder, the density of the phosphor is lowered, and color unevenness may occur in the emitted light from the LED device. Therefore, it is conceivable to reduce the amount of the ceramic binder in the wavelength conversion layer. However, when the amount of the ceramic binder in the wavelength conversion layer is reduced, moisture easily enters the LED device, and the metal inside the LED device is easily corroded. In particular, when the wavelength conversion layer and the metal reflection layer are in contact with each other, a phenomenon in which the light extraction efficiency from the LED device decreases with time was observed. The reason is as follows.

Swellable clay compounds such as smectite contained in the wavelength conversion layer described above are easy to absorb moisture, and more easily conduct electricity. When smectite absorbs moisture, current leaks to the wavelength conversion layer when the LED device is used. As a result, the metal reflective layer in contact with the wavelength conversion layer is corroded, and the light reflectivity of the metal reflective layer is lowered. That is, the light extraction efficiency from the LED device decreases with time.

Similarly, when the metal electrode electrically connected to the LED element corrodes, the resistance value of the metal electrode increases, and when the same external voltage is applied, the brightness of the LED device is reduced. This also leads to a decrease in light extraction efficiency from the LED device over time.

The present invention has been made in view of the above-described problems. That is, the objective of this invention is providing the manufacturing method of the LED device which can maintain favorable light extraction efficiency over a long period of time.

That is, this invention relates to the manufacturing method of the following LED devices.
[1] A substrate, an LED element disposed on the substrate, a metal reflective layer disposed on the substrate and around the LED element, and a wavelength conversion layer covering the LED element and the metal reflective layer A method of preparing an LED device including an LED element and a metal reflective layer disposed on a substrate, and covering the LED element and the metal reflective layer of the LED package. And applying a phosphor dispersion liquid containing phosphor, non-conductive layered clay compound, inorganic oxide fine particles, and solvent to form a wavelength conversion layer, and forming the non-conductive layer The electrical conductivity of the aqueous solution whose density | concentration of a clay compound is 2 mass% is a manufacturing method of the LED apparatus which is 500 microsiemens / cm or less.

[2] The non-conductive layered clay compound is a compound in which the electric conductivity of an aqueous solution in which the concentration of the non-conductive layered clay compound is 2% by mass is 10 to 80 μS / cm. Of manufacturing the LED device.
[3] The non-conductive layered clay compound is a compound in which the electric conductivity of an aqueous solution in which the concentration of the non-conductive layered clay compound is 2% by mass is 150 to 500 μS / cm. Of manufacturing the LED device.

[4] The method for manufacturing an LED device according to any one of [1] to [3], wherein a sealing layer is further formed on the wavelength conversion layer.
[5] The method for manufacturing an LED device according to [4], wherein a resin composition containing a silicone resin or an epoxy resin is applied and cured to form a sealing layer on the wavelength conversion layer.
[6] The method for manufacturing an LED device according to any one of [1] to [5], wherein the non-conductive layered clay compound is a non-swellable layered clay compound.

[7] The non-conductive layered clay compound is one or more compounds selected from the group consisting of muscovite, phlogopite, sericite, fluorine phlogopite, potassium tetrasilicon mica, and synthetic mica. 6] The manufacturing method of the LED device in any one of.
[8] The method for manufacturing an LED device according to any one of [1] to [7], wherein the non-conductive layered clay compound has a water absorption rate of 0.2% by mass or more.
[9] The method for manufacturing an LED device according to any one of [1] to [8], wherein the solvent includes alcohol.

[10] The method for manufacturing an LED device according to any one of [1] to [9], wherein the phosphor dispersion contains a polysiloxane precursor.
[11] The method for manufacturing an LED device according to any one of [1] to [9], wherein a polysiloxane precursor is applied on a cured film of the phosphor dispersion liquid to form the wavelength conversion layer.
[12] The method for manufacturing an LED device according to any one of [1] to [11], wherein the metal part is a metal reflective layer or a protruding electrode disposed on the substrate.
[13] The method for manufacturing an LED device according to any one of [1] to [12], wherein the metal part includes silver.

The current hardly leaks in the wavelength conversion layer of the LED device obtained by the manufacturing method of the present invention. Therefore, the metal reflective layer hardly deteriorates with time, and high light extraction performance is realized over a long period of time.

It is a schematic sectional drawing which shows an example of the LED apparatus of this invention.

Hereinafter, the present invention will be described in detail, but the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist.

1. About the structure of an LED device The example of the structure of the LED device obtained with the manufacturing method of this invention is shown in the schematic sectional drawing of FIG. As shown in FIG. 1, the LED device 100 obtained by the manufacturing method of the present invention is disposed on the substrate 1, the LED element 3 disposed on the substrate 1, and on the substrate 1 and around the LED element 3. In addition, a metal portion composed of the metal reflection layer 2 and the protruding electrode 4 and the wavelength conversion layer 5 covering the LED element 3 and the metal portion are included. The LED device 100 includes a sealing layer 6 that covers the wavelength conversion layer 5 as necessary.

The wavelength conversion layer 5 of the present invention contains a layered clay compound. The layered clay compound is a compound for enhancing the dispersion stability of the phosphor in the phosphor dispersion for preparing the wavelength conversion layer 5. Here, the conventional wavelength conversion layer contains a large amount of layered clay compounds having high hygroscopicity and high electrical conductivity. Therefore, when the layered clay compound absorbs moisture, current easily leaks to the wavelength conversion layer when the LED device is used. When the current leaks, there is a problem that the metal reflection layer and the metal electrode in contact with the wavelength conversion layer corrode, and the light extraction efficiency from the LED device decreases with time.

On the other hand, in the present invention, a non-conductive layered clay compound that hardly conducts electricity to the wavelength conversion layer 5 is included. The non-conductive layered clay compound refers to a layered clay compound having an electric conductivity of 500 μS / cm or less when an aqueous solution having a concentration of 2% by mass is formed. That is, the nonconductive layered clay compound has low electrical conductivity even in a wet state. Therefore, even if the non-conductive layered clay compound absorbs moisture, current leakage to the wavelength conversion layer 5 is suppressed. As a result, corrosion of the metal part is suppressed over a long period of time, and high light extraction efficiency from the LED device 100 is maintained. The electric conductivity of the aqueous solution of the non-conductive layered clay compound is preferably 250 μS / cm or less, more preferably 100 μS / cm or less. In particular, when the electrical conductivity is 10 to 80 μS / cm, corrosion of the metal part is easily suppressed, and high light extraction efficiency from the LED device 100 is easily maintained. On the other hand, when the electrical conductivity is 150 to 500 μS / cm, corrosion of the metal part is suppressed, and the dispersion stability of the phosphor in the phosphor dispersion liquid for preparing the wavelength conversion layer is likely to increase.

The electrical conductivity of the aqueous solution of the non-conductive layered clay compound is measured as follows. The non-conductive layered clay compound and water are mixed so that the concentration of the non-conductive layered clay compound is 2% by mass. And the said liquid mixture is mixed for 5 minutes with an ultrasonic wave, and a nonelectroconductive layered clay compound is fully disperse | distributed. The electrical conductivity of the aqueous solution is measured with an electrical conductivity meter. An example of the electrical conductivity meter is LAQUATwin B771 manufactured by Horiba, Ltd.

1-1. Substrate The substrate 1 may have a cavity (concave portion) as shown in FIG. 1 or may have a flat plate shape. The shape of the cavity that the substrate 1 has is not particularly limited. For example, a truncated cone shape, a truncated pyramid shape, a cylindrical shape, a prismatic shape, or the like may be used.

The substrate 1 preferably has insulating properties and heat resistance, and is preferably made of a ceramic resin or a heat resistant resin. Examples of the heat resistant resin include liquid crystal polymer, polyphenylene sulfide, aromatic nylon, epoxy resin, hard silicone resin, polyphthalic acid amide and the like.

The substrate 1 may contain an inorganic filler. The inorganic filler can be titanium oxide, zinc oxide, alumina, silica, barium titanate, calcium phosphate, calcium carbonate, white carbon, talc, magnesium carbonate, boron nitride, glass fiber, and the like.

Metal wiring is usually formed on the surface of the substrate 1. The metal wiring is a member that supplies electricity to the LED element 3 from a power source (not shown) arranged outside the substrate 1, and the metal reflection layer 2 described later may also serve as the metal wiring. In the LED device 100 shown in FIG. 1, the metal reflection layer 2 also serves as a metal wiring.

1-2. LED element The LED element 3 is electrically connected to a metal wiring formed on the surface of the substrate 1 and emits light of a specific wavelength. The wavelength of the light emitted from the LED element 3 is not particularly limited. The LED element 3 may be, for example, an element that emits blue light (light of about 420 nm to 485 nm) or an element that emits ultraviolet light.

The configuration of the LED element 3 is not particularly limited. When the LED element 3 is an element that emits blue light, the LED element 3 includes an n-GaN compound semiconductor layer (cladding layer), an InGaN compound semiconductor layer (light emitting layer), and a p-GaN compound semiconductor layer. It may be a laminate of (cladding layer) and a transparent electrode layer. The LED element 3 may have a light emitting surface of 200 to 300 μm × 200 to 300 μm, for example. The height of the LED element 3 is usually about 50 to 200 μm. In the LED device 100 shown in FIG. 1, only one LED element 3 is disposed on the substrate 1, but a plurality of LED elements 3 may be disposed on the substrate 1.

The connection method between the LED element 3 and the metal wiring formed on the surface of the substrate 1 is not particularly limited. For example, as shown in FIG. 1, the LED element 3 and the metal wiring (metal reflection layer) 2 may be connected via the protruding electrode 4. Moreover, the LED element 3 and the metal wiring 2 may be connected via a wire. A mode in which the LED element 3 and the metal wiring 2 are connected via the protruding electrode 4 is referred to as a flip chip type. On the other hand, a mode in which the LED element 3 and the metal wiring 2 are connected via a wire is called a wire bonding type.

1-3. Metal part In this invention, a metal part means the metal members formed on the board | substrate 1, for example, consists of the metal reflective layer 2 arrange | positioned on the base material 1 and the circumference | surroundings of the LED element 3, and a metal. This refers to the protruding electrode 4. The metal part is covered with a wavelength conversion layer 5 described later.

When the metal reflection layer 2 is included in the LED device 100, the light emitted from the LED element 3 and the fluorescence emitted from the phosphor in the wavelength conversion layer 5 are reflected to the light extraction surface side. As a result, the light extraction efficiency from the LED device 100 is increased.

As described above, the metal reflection layer 2 may also serve as a metal wiring for supplying electricity to the LED element 3; the pattern of the metal reflection layer 2 depends on the connection method between the LED element 3 and the metal wiring, and the like. Are appropriately selected. The metal reflection layer 2 only needs to be formed at least around the LED element 3, and may be formed between the LED element 3 and the substrate 1 as shown in FIG. 1, for example. Further, when the substrate 1 has a cavity, the metal reflection layer 2 may be formed on the inner wall surface 7 of the cavity. When the metal reflection layer 2 is formed on the cavity inner wall surface 7, light traveling in the horizontal direction on the surface of the wavelength conversion layer 5 can be reflected by the metal reflection layer 2 and extracted.

The metal reflection layer 2 is not particularly limited as long as it is a layer made of a metal capable of reflecting light. For example, it may be a layer made of copper, aluminum, silver, palladium, or an alloy thereof. The thickness of the metal reflective layer 2 is not particularly limited, and is preferably 100 to 1000 μm, more preferably 200 to 600 μm. The metal reflective layer 2 whose surface is silver-plated is particularly easy to improve light reflectivity.

1-4. Wavelength Conversion Layer The wavelength conversion layer 5 is a layer that covers the LED element 3 and the metal part (the metal reflection layer 2, the protruding electrode 4, etc.), and is a layer that is formed by applying a phosphor dispersion described later. .

The wavelength conversion layer 5 includes a phosphor that emits fluorescence upon receiving light (excitation light) emitted from the LED element 3. By mixing the excitation light and the fluorescence, the color of the light from the LED device 100 becomes a desired color. For example, when the light from the LED element 3 is blue and the fluorescence emitted from the phosphor included in the wavelength conversion layer 5 is yellow, the light from the LED device 100 is white.

The wavelength conversion layer 5 contains a non-conductive layered clay compound and inorganic oxide fine particles in addition to the phosphor. When the wavelength conversion layer 5 contains a non-conductive layered clay compound or inorganic oxide fine particles, not only the dispersion stability of the phosphor is increased in the phosphor dispersion liquid when the wavelength conversion layer 5 is produced, but also the wavelength conversion layer 5 The film strength increases.

The wavelength conversion layer 5 may not include a binder or may include a binder. When the binder is contained in the wavelength conversion layer 5, the adhesion between the wavelength conversion layer 5 and the LED element 3 and the adhesion between the wavelength conversion layer 5 and the metal part (for example, the metal reflection layer 2) are enhanced. The type of the binder contained in the wavelength conversion layer 5 is not particularly limited, but is preferably polysiloxane. When the wavelength conversion layer 5 contains a binder made of polysiloxane, the adhesion between the wavelength conversion layer 5 and the LED element 3 or the metal part is likely to increase. Further, since the binder binds the phosphor, inorganic oxide fine particles, non-conductive layered clay compound, and the like, the strength of the wavelength conversion layer 5 tends to increase. Furthermore, when the wavelength conversion layer 5 includes a binder made of polysiloxane, it becomes difficult for the wavelength conversion layer 5 to transmit the hydrogen sulfide gas and the like included in the usage environment of the LED device 100. As a result, the metal part covered with the wavelength conversion layer 5 becomes more difficult to corrode.

On the other hand, when the wavelength conversion layer 5 does not contain a binder, the material of the sealing layer 6 to be described later enters a gap such as a phosphor constituting the wavelength conversion layer 5. As a result, there is no clear interface between the wavelength conversion layer 5 and the sealing layer 6, and even if the LED device 100 changes in temperature, the difference between the expansion rate and contraction rate of the wavelength conversion layer 5 and the sealing layer 6 is reduced. . Accordingly, disconnection of the wire connecting the LED element 3 and the metal wiring formed on the substrate 1 is less likely to occur.

The amount of polysiloxane contained in the wavelength conversion layer 5 is preferably 5 to 50% by mass, more preferably 10 to 30% by mass with respect to the total mass of the wavelength conversion layer 5. If the amount of polysiloxane is less than 5% by mass, the polysiloxane may not be able to bind particles such as phosphors sufficiently. On the other hand, when the amount of polysiloxane exceeds 50% by mass, the amount of the phosphor is relatively lowered, and the density of the phosphor in the wavelength conversion layer 5 is lowered, so that color unevenness may occur.

The thickness of the wavelength conversion layer 5 is preferably 5 to 200 μm, more preferably 10 to 200 μm, and still more preferably 10 to 100 μm. When the thickness of the wavelength conversion layer 5 is less than 5 μm, the amount of the phosphor is reduced and there is a possibility that sufficient fluorescence cannot be obtained. On the other hand, if the thickness of the wavelength conversion layer 5 exceeds 200 μm, the concentration of the phosphor in the wavelength conversion layer 5 becomes excessively low, so that the concentration of the phosphor may not be uniform. The thickness of the wavelength conversion layer 5 means the maximum thickness of the wavelength conversion layer 5 formed on the light emitting surface of the LED element 3. The thickness of the wavelength conversion layer 5 is measured with a laser holo gauge.

1-5. Sealing Layer As shown in FIG. 1, the LED device 100 may include a sealing layer 6. When the LED device 100 includes the sealing layer 6, the LED element 3 and the metal part are protected from external impact, gas, moisture, and the like. As a result, the metal part is less likely to corrode, and high light extraction from the LED device 100 is maintained over a long period of time.

The sealing layer 6 includes transparent resin or translucent ceramic. Examples of the transparent resin include a silicone resin and an epoxy resin. An example of the translucent ceramic includes polysiloxane.

When the sealing layer 6 contains a resin, the thickness of the sealing layer 6 is preferably 25 μm to 5 mm, and more preferably 1 to 3 mm. Generally, it is difficult to make the thickness of the sealing layer 6 containing the resin 25 μm or less. On the other hand, from the viewpoint of downsizing the LED device 100, the thickness of the sealing layer 6 is preferably 5 mm or less. The thickness of the sealing layer 6 means the maximum thickness of the sealing layer 6 formed on the light emitting surface of the LED element 3. The thickness of the sealing layer 6 is measured with a laser holo gauge.

On the other hand, when the sealing layer 6 contains a translucent ceramic, the thickness of the sealing layer 6 is preferably 0.5 to 10 μm, more preferably 0.8 to 5 μm, and still more preferably 1 ~ 2 μm. When the thickness of the sealing layer 6 is less than 0.5 μm, the gas barrier effect of the sealing layer 6 may not be sufficient. On the other hand, if the thickness of the sealing layer 6 exceeds 10 μm, cracks are likely to occur in the sealing layer 6, and in this case as well, there is a possibility that the gas barrier effect cannot be sufficiently obtained. Also in this case, the thickness of the sealing layer 6 means the maximum thickness of the sealing layer 6 formed on the light emitting surface of the LED element 3. The thickness of the sealing layer 6 is measured with a laser holo gauge.

2. Phosphor dispersion liquid The wavelength conversion layer 5 described above is formed by applying a phosphor dispersion liquid containing at least a phosphor, a layered clay compound, inorganic oxide fine particles, and a solvent.

2-1. Phosphor The phosphor contained in the phosphor dispersion liquid may be anything that is excited by light emitted from the LED element 3 and emits fluorescence having a wavelength different from that of the light emitted from the LED element 3. For example, examples of phosphors that emit yellow fluorescence include YAG (yttrium, aluminum, garnet) phosphors. The YAG phosphor receives blue light (wavelength 420 nm to 485 nm) emitted from the blue LED element, and emits yellow fluorescence (wavelength 550 nm to 650 nm).

The phosphor is, for example, 1) An appropriate amount of flux (fluoride such as ammonium fluoride) is mixed with a mixed raw material having a predetermined composition and pressed to form a molded body. 2) The obtained molded body is packed in a crucible and fired in air at a temperature range of 1350 to 1450 ° C. for 2 to 5 hours to obtain a sintered body.

A mixed raw material having a predetermined composition is obtained by sufficiently mixing oxides such as Y, Gd, Ce, Sm, Al, La, and Ga, or compounds that easily become oxides at high temperatures in a stoichiometric ratio. . Moreover, the mixed raw material which has a predetermined composition mixes the solution which dissolved 1) the rare earth elements of Y, Gd, Ce, and Sm in the acid in stoichiometric ratio, and oxalic acid, and obtains a coprecipitation oxide. 2) It can also be obtained by mixing this coprecipitated oxide with aluminum oxide or gallium oxide.

The kind of the phosphor is not limited to the YAG phosphor, and may be another phosphor such as a non-garnet phosphor that does not contain Ce.

The average particle diameter of the phosphor is preferably 1 μm to 50 μm, more preferably 10 μm or less. The larger the particle size of the phosphor, the higher the light emission efficiency (wavelength conversion efficiency). On the other hand, when the particle size of the phosphor is too large, a gap is likely to be generated in the obtained wavelength conversion layer 5 and the strength of the wavelength conversion layer 5 is likely to be reduced. The average particle diameter of the phosphor refers to the value of D50 measured with a laser diffraction particle size distribution meter. Examples of the laser diffraction particle size distribution measuring device include a laser diffraction particle size distribution measuring device manufactured by Shimadzu Corporation.

The amount of the phosphor contained in the phosphor dispersion is preferably 10 to 99% by mass, more preferably 20 to 97% by mass with respect to the total mass of the solid content of the phosphor dispersion. When the concentration of the phosphor is less than 10% by mass, there is a possibility that the fluorescence cannot be sufficiently obtained from the obtained wavelength conversion layer 5. On the other hand, when the amount of the phosphor exceeds 99% by mass, the amount of the layered clay compound and the amount of the inorganic oxide fine particles are relatively decreased, and the dispersion stability of the phosphor in the phosphor dispersion liquid is lowered. There is a case.

2-2. Layered clay compound When the layered clay compound is contained in the phosphor dispersion liquid, the viscosity of the phosphor dispersion liquid increases, and sedimentation of the phosphor is suppressed. Furthermore, the strength of the obtained wavelength conversion layer 5 is increased.

As described above, the layered clay compound is mainly composed of a non-conductive layered clay compound having low conductivity. If the layered clay compound is a non-conductive layered clay compound, it becomes difficult for the current to leak into the wavelength conversion layer 5.

The non-conductive layered clay compound is not particularly limited as long as it is a layered clay compound satisfying the above electrical conductivity, but non-swelling such as muscovite, phlogopite, sericite, fluorine phlogopite, potassium tetrasilicon mica, synthetic mica, etc. It is preferable that it is a natural clay compound. In general, the non-swelling clay compound is less likely to take moisture into the molecular structure, so the electrical conductivity tends to be low.

The surface of the non-conductive layered clay compound may be modified (surface treatment) with an ammonium salt or the like. When the surface of the non-conductive layered clay compound is modified, the non-conductive layered clay compound is easily dispersed in the phosphor dispersion liquid.

On the other hand, the water absorption of the non-conductive layered clay compound is preferably 0.2% by mass or more, more preferably 0.5 to 5% by mass, and further preferably 1 to 2% by mass. The water absorption rate of the non-conductive layered clay compound is preferably low to some extent from the viewpoint of suppressing the electrical conductivity, but if the water absorption rate is less than 0.2% by mass, the water absorption rate is dispersed in the phosphor dispersion. It becomes difficult. As a result, the viscosity of the phosphor dispersion liquid is difficult to increase, and sedimentation of the phosphor may not be sufficiently suppressed. The water absorption of the non-conductive layered clay compound is measured with a moisture meter. Examples of the moisture meter include MOC-120H manufactured by Shimadzu Corporation.

The layered clay compound may contain a clay compound (other clay compound) other than the non-conductive layered clay compound. Examples of other clay compounds include smectite clay minerals such as hectorite, saponite, stevensite, beidellite, montmorillonite, nontronite, or bentonite, and swellables such as sodium tetrasilicon fluorine mica and lithium tetrasilicon fluorine mica. Clay compounds and the like are included.

The average particle size of the layered clay compound (non-conductive layered clay compound and other clay compounds) is preferably from 0.1 to 100 μm, more preferably from 1 to 50 μm. When the size of the layered clay compound is 1 μm or more, the above-described viscosity improving effect is easily obtained. On the other hand, if the size of the layered clay compound is larger than 50 μm, the light transmittance of the obtained wavelength conversion layer 5 may be lowered. The size of the layered clay compound is measured by a Coulter counter method or the like.

The amount of the non-conductive layered clay compound contained in the phosphor dispersion is preferably 0.3 to 20% by mass, more preferably 0.5 to 15% by mass with respect to the total mass of the solid content of the phosphor dispersion. %. When the concentration of the non-conductive layered clay compound is less than 0.3% by mass, the viscosity of the phosphor dispersion liquid is not sufficiently increased. Further, the strength of the obtained wavelength conversion layer 5 is not sufficiently increased. On the other hand, when the concentration of the non-conductive layered clay compound exceeds 20% by mass, the amount of the phosphor is relatively reduced and sufficient fluorescence cannot be obtained. On the other hand, the amount of the other clay compound is preferably 2% by mass or less with respect to the amount of the non-conductive layered clay compound contained in the phosphor dispersion liquid, and it is particularly preferable that no other clay compound is contained. .
Note that the viscosity does not increase as the proportion of the layered clay compound in the phosphor dispersion increases. Viscosity is determined by the content ratio with other components such as the amount of solvent in the phosphor dispersion and the amount of phosphor.

2-3. Inorganic oxide fine particles When the inorganic oxide fine particles are contained in the phosphor dispersion liquid, the viscosity of the phosphor dispersion liquid is further increased. Examples of the inorganic oxide fine particles include silicon oxide, titanium oxide, zinc oxide, aluminum oxide, zirconium oxide and the like. The surface of the inorganic oxide fine particles may be treated with a silane coupling agent or a titanium coupling agent.

The inorganic oxide fine particles may be porous particles, and the specific surface area is preferably 200 m ² / g or more. When the inorganic oxide fine particles are porous, the solvent enters the porous voids, so that the viscosity of the phosphor dispersion liquid tends to increase. However, the viscosity of the phosphor dispersion liquid is not simply determined by the amount of the inorganic oxide fine particles, but also varies depending on the ratio of the inorganic oxide fine particles and the solvent, the amount of the layered clay compound, and the like.

The average primary particle size of the inorganic oxide fine particles is preferably 5 to 100 nm, more preferably 5 to 80 nm, and still more preferably 5 to 50 nm. When the average primary particle size of the inorganic oxide fine particles is within such a range, the viscosity of the phosphor dispersion liquid tends to increase. The average primary particle size of the inorganic oxide fine particles is measured by a Coulter counter method.

The amount of inorganic oxide fine particles contained in the phosphor dispersion is preferably 1 to 40% by mass, more preferably 1 to 20% by mass, and still more preferably 1%, based on the total solid content of the phosphor dispersion. ~ 10% by mass. When the amount of the inorganic oxide fine particles is too small, the viscosity of the phosphor dispersion liquid is not sufficiently increased. On the other hand, if the amount of the inorganic oxide fine particles is too large, the amount of the layered clay compound is relatively reduced, and in the phosphor dispersion liquid, the phosphor may settle or the dispersibility of the phosphor may be lowered. .

2-4. Solvent The phosphor dispersion liquid contains a solvent. The solvent is not particularly limited as long as the phosphor, the layered clay compound, and the inorganic oxide fine particles can be uniformly dispersed, but a solvent having a boiling point of 250 ° C. or lower is preferable. When the boiling point of the solvent is 250 ° C. or less, the drying rate of the phosphor dispersion liquid tends to increase.

Examples of the solvent include monoalcohols such as methanol, ethanol, propanol, and butanol; ethylene glycol, propylene glycol, diethylene glycol, glycerin, 1,3-butanediol, 1,4-butanediol, and the like. The phosphor dispersion liquid may contain only one kind of solvent, or two or more kinds.

The solvent may contain water. When water is contained in the phosphor dispersion liquid, water enters between layers of the layered clay compound, and the viscosity of the phosphor dispersion liquid is likely to increase.

The amount of water contained in the phosphor dispersion is preferably 5% by mass or less, and more preferably 2% by mass or less with respect to the entire phosphor dispersion. When there is too much content of water in a fluorescent substance dispersion liquid, the wettability of a fluorescent substance dispersion liquid will fall. For this reason, when the phosphor dispersion liquid is applied to the surface to be coated (the light emitting surface of the LED element 3, the surface of the metal reflection layer 2, the side surface of the protruding electrode 4), it is difficult to form a uniform coating film.

The total amount of the solvent contained in the phosphor dispersion liquid is appropriately set according to the viscosity of the entire phosphor dispersion liquid. Usually, the total amount of the solvent contained in the phosphor dispersion is preferably 30 to 90% by mass, more preferably 40 to 70% by mass with respect to the entire phosphor dispersion.

2-5. Method for preparing phosphor dispersion liquid A phosphor dispersion liquid is prepared by mixing and stirring a phosphor, a layered clay compound, inorganic oxide fine particles, and a solvent. The stirrer can be, for example, a magnetic stirrer, an ultrasonic dispersing device, a homogenizer, a stirring mill, a blade kneading stirrer, a thin-film swirling disperser, a high-pressure impact disperser, a rotation and revolution mixer, and the like.

Specific examples of the stirrer include known Ultra Turrax (manufactured by IKA Japan), TK homomixer (manufactured by Primix), TK pipeline homomixer (manufactured by Primix), TK Philmix (manufactured by Primix), Claremix. (M-Technics), Claire SS5 (M-Technics), Cavitron (Eurotech), media flow stirrers such as Fine Flow Mill (Pacific Kiko), Viscomill (Imex), Apex Mill (manufactured by Kotobuki Kogyo Co., Ltd.), Star Mill (manufactured by Ashizawa, Finetech), DMPA / S Super Flow (manufactured by Nihon Eirich), MPP Mill (manufactured by Inoue Seisakusho), spike mill (manufactured by Inoue Seisakusho), Mighty Mill Media such as Inoue Mfg. Co., Ltd., SC Mill (Mitsui Mining Co., Ltd.) (Manufactured by Sugino Machine Co., Ltd.) and Altimizer agitator, Nanomizer (manufactured by Yoshida Kikai), includes a high-pressure impact type dispersing device, etc., such as NANO 3000 (manufactured by Bitsubusha). In addition, a rotating and rotating mixer such as Awatori Nertaro (manufactured by Shinky Corporation) and an ultrasonic dispersion device are also suitable for preparing the phosphor dispersion.

Since the phosphor is very hard particles, it is preferable to avoid wear at the portion where the stirrer and the phosphor dispersion liquid are in contact with each other, and mixing of wear powder associated therewith. Specifically, the material of the portion where the stirrer and the phosphor dispersion are in contact with each other may be ceramic such as titania, zirconia, alumina, or silicone carbide. It is also preferable to coat the wetted part with titanium-based oxide, chromium-based nitride, diamond-like carbon.

The viscosity of the obtained phosphor dispersion at 25 ° C. is preferably 10 to 1000 cP, more preferably 12 to 800 cP, and still more preferably 20 to 600 cP. The viscosity of the phosphor dispersion is adjusted by the amount of the solvent, the amount of the layered clay compound, the amount of the inorganic oxide fine particles, and the like. The viscosity of the phosphor dispersion is measured with a vibration viscometer.

3. Manufacturing method of LED device The manufacturing method of the LED device 100 of the present invention includes the following two steps.
(1) Step of preparing an LED package in which the LED element 3 and the metal part are arranged on the substrate 1 (2) The wavelength conversion layer 5 is formed so as to cover the LED element 3 and the metal part arranged in the LED package. Forming process

The manufacturing method of the present invention may include (3) a step of forming the sealing layer 6 on the wavelength conversion layer 5 as necessary.

3-1. LED Package Preparation Step In the LED package preparation step, a substrate 1 on which a metal part (a metal reflection layer 2, a metal wiring, a protruding electrode 4, etc.) is formed on a substrate 1 is prepared, and an LED element 3 is mounted on the substrate 1. Deploy. The substrate 1 on which the metal reflection layer 2 and the metal wiring are formed is produced by a known method. The method for manufacturing the substrate 1 may be a method of integrally molding a resin and a metal plate (such as a copper plate) patterned into a desired shape. In order to improve the light reflectivity of the metal reflective layer 2, the surface of the metal plate may be further plated.

The LED element 3 is fixed on the substrate 1 on which the metal reflective layer 2 is formed, and the LED element 3 and the metal wiring are electrically connected. The method for fixing the LED element 3 to the substrate 1 is not particularly limited, and may be a method for fixing the LED element 3 by, for example, die bonding. Further, the electrical connection between the LED element 3 and the metal wiring may be via a wire or via the protruding electrode 4.

3-2. Wavelength conversion layer forming step The wavelength conversion layer 5 is formed so as to cover the LED element 3 and the metal part of the LED package described above. As described above, the wavelength conversion layer 5 obtained by the method of the present invention does not leak a current even if it absorbs moisture. Therefore, the wavelength conversion layer 5 may not contain a binder, but a ceramic binder (polysiloxane) is used. Further, it may be included. Therefore, the film forming method of the wavelength conversion layer 5 can be the following three methods.

(I) Method of forming wavelength conversion layer 5 by applying and curing phosphor dispersion (first method)
(Ii) A method of forming the wavelength conversion layer 5 by applying and curing a mixed solution of a phosphor dispersion and a polysiloxane precursor (second method)
(Iii) Applying and curing the phosphor dispersion liquid to form a cured film of the phosphor dispersion liquid, and separately applying a polysiloxane precursor on the cured film of the phosphor dispersion liquid Method for forming wavelength conversion layer 5 (third method)

3-2-1. First Method In the first method, the phosphor dispersion liquid is applied so that the phosphor dispersion liquid covers the LED element 3 and the metal part (for example, the metal reflection layer 2). The method for applying the phosphor dispersion liquid is not particularly limited, and may be a conventionally known method such as a bar coating method, a spin coating method, a spray coating method, a dispensing method, a jet dispensing method, and an ink jet method. In particular, the spray coating method is preferable because a thin film can be formed.

After applying the phosphor dispersion liquid, the solvent contained in the coating film is dried to cure the coating film. The temperature at which the solvent is dried is usually 20 to 200 ° C., preferably 25 to 150 ° C. There exists a possibility that a coating film may not fully dry that the temperature at the time of solvent drying is less than 20 degreeC. On the other hand, if the drying temperature exceeds 200 ° C., the LED element 3 may be affected.

3-2-2. Second Method In the second method, a mixed liquid of the above-described phosphor dispersion liquid and a polysiloxane precursor is prepared, and the mixed liquid is coated on the LED element 3 and a metal part (for example, the metal reflection layer 2). As described above, the phosphor dispersion liquid is applied. You may mix a solvent with a liquid mixture as needed. The mixing method of the phosphor dispersion and the polysiloxane precursor is not particularly limited, and may be a general mixing / stirring method.

The polysiloxane precursor mixed with the phosphor dispersion may be a bifunctional, trifunctional, or tetrafunctional silane compound (monomer); or an oligomer obtained by polymerizing these.

Examples of tetrafunctional silane compounds include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, tetrapentyloxysilane, tetraphenyloxysilane, trimethoxymonoethoxysilane, dimethoxydiethoxysilane, triethoxymono Methoxysilane, trimethoxymonopropoxysilane, monomethoxytributoxysilane, monomethoxytripentyloxysilane, monomethoxytriphenyloxysilane, dimethoxydipropoxysilane, tripropoxymonomethoxysilane, trimethoxymonobutoxysilane, dimethoxydibutoxysilane , Triethoxymonopropoxysilane, diethoxydipropoxysilane, tributoxymonopropoxysilane, dimethoxymonoethoxymonobutoxy Silane, diethoxymonomethoxymonobutoxysilane, diethoxymonopropoxymonobutoxysilane, dipropoxymonomethoxymonoethoxysilane, dipropoxymonomethoxymonobutoxysilane, dipropoxymonoethoxymonobutoxysilane, dibutoxymonomethoxymonoethoxysilane, Examples include tetraalkoxysilanes such as dibutoxymonoethoxymonopropoxysilane and monomethoxymonoethoxymonopropoxymonobutoxysilane, and tetraaryloxysilane. Among these, tetramethoxysilane and tetraethoxysilane are preferable.

Examples of trifunctional silane compounds include trimethoxysilane, triethoxysilane, tripropoxysilane, tripentyloxysilane, triphenyloxysilane, dimethoxymonoethoxysilane, diethoxymonomethoxysilane, dipropoxymonomethoxysilane, di Propoxymonoethoxysilane, dipentyloxylmonomethoxysilane, dipentyloxymonoethoxysilane, dipentyloxymonopropoxysilane, diphenyloxylmonomethoxysilane, diphenyloxymonoethoxysilane, diphenyloxymonopropoxysilane, methoxyethoxypropoxysilane, monopropoxydimethoxysilane Monopropoxydiethoxysilane, monobutoxydimethoxysilane, monopentyloxydiethoxysilane, monophenyl Monohydrosilane compounds such as ruoxydiethoxysilane; methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltripentyloxysilane, methylmonomethoxydiethoxysilane, methylmonomethoxydipropoxysilane, methylmonomethoxydipentyl Monomethylsilane compounds such as oxysilane, methylmonomethoxydiphenyloxysilane, methylmethoxyethoxypropoxysilane, methylmonomethoxymonoethoxymonobutoxysilane; ethyltrimethoxysilane, ethyltripropoxysilane, ethyltripentyloxysilane, ethyltriphenyloxy Silane, ethyl monomethoxydiethoxysilane, ethyl monomethoxydipropoxysilane, ethyl monomethoxydipentyloxy Monoethylsilane compounds such as lan, ethylmonomethoxydiphenyloxysilane, ethylmonomethoxymonoethoxymonobutoxysilane; propyltrimethoxysilane, propyltriethoxysilane, propyltripentyloxysilane, propyltriphenyloxysilane, propylmonomethoxydi Monopropylsilane compounds such as ethoxysilane, propylmonomethoxydipropoxysilane, propylmonomethoxydipentyloxysilane, propylmonomethoxydiphenyloxysilane, propylmethoxyethoxypropoxysilane, propylmonomethoxymonoethoxymonobutoxysilane; butyltrimethoxysilane, Butyltriethoxysilane, Butyltripropoxysilane, Butyltripentyloxysilane, Butyltriphenyl Monobutylsilane compounds such as oxysilane, butylmonomethoxydiethoxysilane, butylmonomethoxydipropoxysilane, butylmonomethoxydipentyloxysilane, butylmonomethoxydiphenyloxysilane, butylmethoxyethoxypropoxysilane, butylmonomethoxymonoethoxymonobutoxysilane Is included. Among these, methyltrimethoxysilane and methyltriethoxysilane are more preferable, and methyltrimethoxysilane is more preferable.

Examples of bifunctional silane compounds include dimethoxysilane, diethoxysilane, dipropoxysilane, dipentyloxysilane, diphenyloxysilane, methoxyethoxysilane, methoxypropoxysilane, methoxypentyloxysilane, methoxyphenyloxysilane, ethoxypropoxysilane , Ethoxypentyloxysilane, ethoxyphenyloxysilane, methyldimethoxysilane, methylmethoxyethoxysilane, methyldiethoxysilane, methylmethoxypropoxysilane, methylmethoxypentyloxysilane, methylmethoxyphenyloxysilane, ethyldipropoxysilane, ethylmethoxypropoxy Silane, ethyldipentyloxysilane, ethyldiphenyloxysilane, propyldimethoxysilane, propyl Toxiethoxysilane, Propylethoxypropoxysilane, Propyldiethoxysilane, Propyldipentyloxysilane, Propyldiphenyloxysilane, Butyldimethoxysilane, Butylmethoxyethoxysilane, Butyldiethoxysilane, Butylethoxypropoxysilane, Butyldipropoxysilane, Butyl Methyldipentyloxysilane, butylmethyldiphenyloxysilane, dimethyldimethoxysilane, dimethylmethoxyethoxysilane, dimethyldiethoxysilane, dimethyldipentyloxysilane, dimethyldiphenyloxysilane, dimethylethoxypropoxysilane, dimethyldipropoxysilane, diethyldimethoxysilane, diethyl Methoxypropoxysilane, diethyldiethoxysilane, diethyleth Cypropoxysilane, dipropyldimethoxysilane, dipropyldiethoxysilane, dipropyldipentyloxysilane, dipropyldiphenyloxysilane, dibutyldimethoxysilane, dibutyldiethoxysilane, dibutyldipropoxysilane, dibutylmethoxypentyloxysilane, dibutylmethoxyphenyl Oxysilane, methylethyldimethoxysilane, methylethyldiethoxysilane, methylethyldipropoxysilane, methylethyldipentyloxysilane, methylethyldiphenyloxysilane, methylpropyldimethoxysilane, methylpropyldiethoxysilane, methylbutyldimethoxysilane, methylbutyl Diethoxysilane, methylbutyldipropoxysilane, methylethylethoxypropoxysilane, ethylpropyl Includes propyldimethoxysilane, ethylpropylmethoxyethoxysilane, dipropyldimethoxysilane, dipropylmethoxyethoxysilane, propylbutyldimethoxysilane, propylbutyldiethoxysilane, dibutylmethoxyethoxysilane, dibutylmethoxypropoxysilane, dibutylethoxypropoxysilane, etc. It is. Of these, dimethoxysilane, diethoxysilane, methyldimethoxysilane, and methyldiethoxysilane are preferable.

On the other hand, the oligomer of the silane compound is obtained by hydrolyzing one or more of the silane compounds in the presence of an acid catalyst, water, and an organic solvent, and then subjecting this to a condensation reaction.

When the polysiloxane precursor is an oligomer, the mass average molecular weight of the oligomer is preferably 1000 to 3000, more preferably 1200 to 2700, and further preferably 1500 to 2000. When the mass average molecular weight of the oligomer exceeds 3000, the viscosity of the mixed liquid of the phosphor dispersion liquid and the polysiloxane precursor becomes excessively high, and it may be difficult to form a uniform film. The mass average molecular weight is a value (polystyrene conversion) measured by gel permeation chromatography. The mass average molecular weight of the oligomer is adjusted by the reaction conditions (particularly the reaction time) at the time of oligomer preparation.

The solvent that can be mixed with the phosphor dispersion and the polysiloxane precursor should be a solvent that can dissolve or uniformly disperse the polysiloxane precursor and has good compatibility with the phosphor dispersion. For example, the solvent for preparing the oligomer may be mixed, or different solvents may be mixed.

Examples of the solvent include monohydric alcohols such as methanol, ethanol, propanol and n-butanol; alkyl carboxylic acid esters such as methyl-3-methoxypropionate and ethyl-3-ethoxypropionate; ethylene glycol, diethylene glycol, Polyhydric alcohols such as propylene glycol, glycerin, trimethylolpropane, hexanetriol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono Propyl ether, diethylene glycol monobutyl ether, propylene glycol Monoethers of polyhydric alcohols such as methyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, or their monoacetates; ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether Polyhydric alcohol ethers in which all hydroxyl groups of polyhydric alcohols such as ethylene glycol dibutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, and diethylene glycol methyl ethyl ether are all alkyl etherified; methyl acetate, ethyl acetate , Butyl acetate, etc. Ester ethers; include the like; ketones such as acetone, methyl ethyl ketone and methyl isoamyl ketone. In the mixed liquid of the phosphor dispersion liquid and the polysiloxane precursor, only one kind of these solvents may be mixed, or two or more kinds may be mixed.

The method for applying the mixed liquid of the phosphor dispersion and the polysiloxane precursor is not particularly limited, and may be the same as the method for applying the phosphor dispersion in the first method described above.

After applying the above mixed solution, the coating film is heated to 100 ° C. or higher, preferably 150 to 300 ° C., and the coating film is dried and cured. When the heating temperature is less than 100 ° C., water generated during the dehydration condensation of the polysiloxane precursor and the solvent contained in the mixed solution cannot be sufficiently removed, and the light resistance of the coating film may be lowered.

3-2-3. Third Method In the third method, the phosphor dispersion liquid described above is applied and cured on the LED element 3 and the metal part (for example, the metal reflection layer 2) to form a cured film of the phosphor dispersion liquid. And a step of separately applying a polysiloxane precursor on the cured film of the phosphor dispersion liquid.

The phosphor dispersion liquid is applied so as to cover the LED element 3 and the metal part. The method for applying and curing the phosphor dispersion liquid may be the same as the method for applying the phosphor dispersion liquid in the first method described above.

After forming the cured film of the phosphor dispersion liquid, a polysiloxane precursor is applied so as to cover the cured film. When a polysiloxane precursor is applied onto the cured film of the phosphor dispersion liquid, the polysiloxane precursor enters between the phosphor, the inorganic oxide fine particles, the layered clay compound, and the like. As a result, in the obtained wavelength conversion layer 5, phosphors, inorganic oxide fine particles, and layered clay compounds are bound by polysiloxane.

The polysiloxane precursor applied onto the cured film of the phosphor dispersion liquid may be the same as the polysiloxane precursor mixed with the phosphor dispersion liquid in the second method. When applying the polysiloxane precursor, the polysiloxane precursor and a solvent may be mixed as necessary.

The method for applying the polysiloxane precursor is not particularly limited, and may be the same as the method for applying the phosphor dispersion. After the polysiloxane precursor is applied, the coating film is heated to 100 ° C. or more, preferably 150 to 300 ° C., and the coating film is dried and cured. If the heating temperature is less than 100 ° C., water generated during the dehydration condensation of the polysiloxane precursor cannot be sufficiently removed, and the light resistance of the coating film may be lowered.

3-3. Sealing Layer Formation Step As described above, the manufacturing method of the present invention may include a formation step of the sealing layer 6 that covers the wavelength conversion layer 5. The formation method of the sealing layer 6 is appropriately selected according to the components contained in the sealing layer 6.

For example, in the case of forming the sealing layer 6 containing a resin, a resin composition containing the resin (silicone resin, epoxy resin, etc.) or a precursor thereof is prepared, and the composition is applied on the wavelength conversion layer 5・ Curing. The resin composition may contain a solvent. The solvent is not particularly limited as long as it can dissolve the resin or the precursor thereof, for example, hydrocarbons such as toluene and xylene; ketones such as acetone and methyl ethyl ketone; diethyl ether, tetrahydrofuran and the like And ethers such as propylene glycol monomethyl ether acetate and ethyl acetate.

The coating method of the resin composition is not particularly limited, and may be a coating method using a general coating apparatus such as a dispenser. The curing method and curing conditions of the resin composition are appropriately selected depending on the type of resin. An example of the curing method is heat curing.

On the other hand, when forming the sealing layer 6 containing polysiloxane, a polysiloxane precursor-containing liquid containing a polysiloxane precursor is prepared, and the containing liquid is applied and cured on the wavelength conversion layer 5. The polysiloxane precursor-containing liquid may contain a solvent. The polysiloxane precursor and the solvent contained in the polysiloxane precursor-containing liquid can be the same as the polysiloxane precursor and the solvent applied in the film forming step (third method) of the wavelength conversion layer 5 described above. Moreover, the application | coating method and hardening method of a polysiloxane precursor containing composition can also be the same method as the film-forming process (3rd method) of the above-mentioned wavelength conversion layer 5. FIG.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited by this.

(1) Physical properties of layered clay compound (Measurement of electrical conductivity of 2% by weight aqueous solution of layered clay compound)
The layered clay compound and pure water shown in Table 1 were mixed so that the concentration of the layered clay compound was 2% by mass. The mixed solution was dispersed with ultrasonic waves for 5 minutes to sufficiently disperse the layered clay compound. The electrical conductivity of the obtained aqueous solution was measured with an electrical conductivity meter LAQUATwin B-771 manufactured by Horiba, Ltd. The measurement results are shown in Table 1.

(Measurement of water absorption of layered clay compounds)
The water absorption rate of the layered clay compound was measured using a moisture meter MOC-120H manufactured by Shimadzu Corporation. The measurement results are shown in Table 1.

(2) Material of phosphor dispersion liquid In addition to the layered clay compound, the following materials were used for the phosphor dispersion liquid.
・ Phosphor YAG phosphor (Y-468, manufactured by Nemoto Special Chemical)
Silicon oxynitride phosphor (ASK-23 manufactured by Nemoto Special Chemical Co., Ltd.)
・ Inorganic oxide fine particles Silica (RX300 manufactured by Nippon Aerosil Co., Ltd.)
Alumina (Alu-C made by Nippon Aerosil Co., Ltd.)
・ Solvent Solvent (1) Mixture of 1,3-butanediol and ethyl alcohol (weight ratio 3: 2)
Solvent (2) Propylene glycol and isopropyl alcohol mixture (weight ratio 3: 2)

Polysiloxane precursor-containing liquid Polysiloxane precursor-containing liquid prepared by the following method (1)
Polysiloxane precursor-containing liquid prepared by the following method (2)

<Preparation Method of Polysiloxane Precursor-Containing Liquid (1)>
80 g of tetramethoxysilane, 72 g of methyltrimethoxysilane, 140 g of n-butanol, 140 g of methyl-3-methoxypropionate, 70 g of water, and 0.1 g of nitric acid were stirred at 25 ° C. for 3 hours to cause a hydrolysis reaction. Then, it was made to react at 26 degreeC for 2 days, and the reaction solution containing a polysiloxane precursor (1) was obtained. To 400 g of the reaction solution, 100 g of n-butanol and 100 g of methyl-3-methoxypropionate were mixed to obtain a polysiloxane precursor-containing liquid (1).

When the molecular weight of the polysiloxane precursor (1) was measured by GPC, the weight average molecular weight in terms of polystyrene was 1600.

<Preparation Method of Polysiloxane Precursor-Containing Liquid (2)>
75 g of methyltriethoxysilane was dissolved in 400 g of ethylene glycol dimethyl ether and stirred. A mixture of 25 g of pure water and 0.1 g of concentrated nitric acid was slowly added dropwise to the mixture. The resulting solution was stirred at 25 ° C. for 3 hours and allowed to stand at room temperature for 6 days to obtain a polysiloxane precursor (2). The obtained solution was distilled under reduced pressure at 120 to 140 mmHg and 40 ° C. for 1 hour to obtain a polysiloxane precursor-containing liquid (2).

When the molecular weight of the polysiloxane precursor (2) was measured by GPC, the weight average molecular weight in terms of polystyrene was 1500.

(3) Preparation of phosphor dispersion liquid (3.1) Preparation of phosphor dispersion liquid (1) 50 parts by mass of YAG phosphor, 2 parts by mass of layered clay compound (1), and inorganic oxide fine particles (silica product name) : RX300, manufactured by Nippon Aerosil Co., Ltd.) and 2 parts by mass of a mixed liquid of 1,3-butanediol and ethyl alcohol (weight ratio 3: 2) were mixed. The obtained mixed liquid was dispersed for 5 minutes at 1000 rpm with a rotation and revolution mixer (Awatori Netaro ARE-310: manufactured by Sinky Corporation) to prepare a phosphor dispersion liquid (1).

(3.2) Preparation of phosphor dispersions (2) to (21) Phosphor dispersions (2) to (21) were prepared in the same manner as phosphor dispersion (1) except that the compositions shown in Table 2 below were used. 21) was prepared.

(4) Production of LED device <Example 1>
An aromatic polyamide circular substrate (opening diameter 3 mm, bottom surface diameter 2 mm, opening wall inclination angle 60 °) having a metal reflection layer 2 (silver plating) shown in FIG. 1 was prepared. One blue LED element 3 (cuboid: 200 μm × 300 μm × 100 μm) was fixed to the center of the opening of the substrate 1 with a die-bonding adhesive. In addition, the anode electrode and the cathode electrode of the LED element were respectively connected by wires to obtain an LED package.

The above-mentioned phosphor dispersion liquid (1) was applied by spraying so as to cover the LED element 3 of the LED package and the metal reflection layer 2. The spray pressure at the time of spray application was 0.2 MPa. Moreover, the relative moving speed of the spray nozzle and the LED package was appropriately adjusted so that the thickness of the obtained wavelength conversion layer became a desired thickness. Specifically, the thickness of the wavelength conversion layer (relative movement speed between the spray nozzle and the LED package) was adjusted so that the chromaticity (x value) of white light emitted from the obtained LED element was 0.33. After application of the phosphor dispersion, heating was performed at 150 ° C. for 1 hour to form a wavelength conversion layer.

<Examples 2 to 13, 16 to 17, and Comparative Examples 1 to 8>
It implemented except having applied the fluorescent substance dispersion liquid (or liquid mixture of fluorescent substance dispersion liquid and polysiloxane precursor containing liquid) shown in the said Table 2 instead of the fluorescent substance dispersion liquid (1) in Example 1. As in Example 1, a wavelength conversion layer was formed.

<Example 14>
Instead of the phosphor dispersion liquid (1) in Example 1, as shown in Table 2 above, the phosphor dispersion liquid (6) was applied and cured in the same manner as in Example 1. Furthermore, the above-mentioned polysiloxane precursor containing liquid (2) was apply | coated on the hardened | cured material of fluorescent substance dispersion liquid. Then, it heated at 150 degreeC for 1 hour, and formed the wavelength conversion layer containing the hardened | cured material of a phosphor dispersion liquid, and polysiloxane. The coating amount of the polysiloxane precursor-containing liquid (2) was adjusted so that the mass of the polysiloxane was 10% by mass with respect to the mass of the entire wavelength conversion layer to be obtained.

<Example 15>
Instead of the phosphor dispersion liquid (1) in Example 1, the phosphor dispersion liquid (20) was applied as shown in Table 2 above. Then, it heated at 150 degreeC for 1 hour, and formed the wavelength conversion layer into a film.
Furthermore, the above-mentioned polysiloxane precursor (2) was apply | coated on the wavelength conversion layer, and it heated at 150 degreeC for 1 hour, and formed the sealing layer into a film. The thickness of the sealing layer was 5 μm.

<Evaluation>
The following tests were conducted on samples prepared in each example and comparative example. The results are shown in Table 2 above.

(Evaluation of adhesion of wavelength conversion layer)
The sample produced in each Example and the comparative example was freely dropped 20 times on the iron plate from the position of 60 cm in height. Each time it was dropped once, the wavelength conversion layer was observed, and the adhesion between the wavelength conversion layer and the LED element or the metal reflection layer was evaluated as follows.
A: The wavelength conversion layer was not lost even after 20 drops. O: The wavelength conversion layer was lost due to 6 to 20 drops.

(Measurement of initial total luminous flux value)
Phenyl silicone (manufactured by Shin-Etsu Chemical Co., Ltd .: KER-6000) is applied with a dispenser on the wavelength conversion layer of the sample prepared in each example and comparative example, and heated at 150 ° C. for 1 hour to form a sealing layer. did. The obtained sealing layer had a thickness of 2 mm.

A current of 20 mA was passed through the LED device on which the sealing layer was formed; the chromaticity of the emission color and the total luminous flux of each LED device were measured. The chromaticity and total luminous flux were measured with a spectral radiance meter CS-1000A manufactured by Konica Minolta Sensing. As described above, the chromaticity x value of each LED device is adjusted to 0.33.

Then, the total luminous flux value of the LED device of Example 1 was used as a reference (100), and the total luminous flux value of each LED device was evaluated according to the following criteria.
A: The total luminous flux value is 102 or more with respect to the total luminous flux value 100 of the LED device of Example 1. O: The total luminous flux value is 98 or more and less than 102 with respect to the total luminous flux value 100 of the LED device of Example 1. Is

(Lighting evaluation after heat shock test)
Thirty LED devices after the initial total luminous flux value measurement were prepared. These samples were subjected to heat shock treatment using a heat shock tester (TSE-11 manufactured by Espec Corp.) at −40 ° C. (30 minutes) and 120 ° C. (30 minutes) as one cycle. The LED device was turned on after each cycle in order to confirm the disconnection at the junction between the wire and the substrate (wiring). The following criteria were used for evaluation.
◎: No lighting sample was generated even after 2000 cycles of heat shock treatment. ○: No lighting sample was generated even after 1500 cycles of heat shock processing. The above samples were not lit

(Total luminous flux maintenance rate after wet heat environment test)
After the initial total luminous flux value was measured, the LED device was charged in a high-temperature and high-humidity tank (trade name: SH251 manufactured by Espec Co., Ltd.) at 85 ° C. and 85% Rh with a current of 20 mA flowing, and taken out after 1000 hours. And based on the following formula | equation, the total luminous flux maintenance factor was computed, and the following references | standards evaluated.
Total luminous flux maintenance factor = total luminous flux value after 1000 hours of wet heat environment test / initial total luminous flux value × 100
A: Total luminous flux maintenance factor was 97% or more. O: Total luminous flux maintenance factor was 95% or more and less than 97%. Δ: Total luminous flux maintenance factor was 90% or more and less than 95%. Luminous flux maintenance factor was less than 90%

(Sedimentation stability of phosphor dispersion)
With respect to dispersions 1 to 20, generation of a supernatant was observed when allowed to stand for 24 hours.
A: No generation of supernatant was observed. O: A slight generation of supernatant was observed. (Result)
As shown in Table 2 above, when the non-conductive layered clay compound having an electric conductivity of 500 μS / cm or less was contained in the wavelength conversion layer, the total luminous flux maintenance factor after the wet heat environment test was high (Examples). 1-17). A non-conductive layered clay compound is difficult to conduct electricity even if it absorbs moisture. Therefore, it is surmised that the wavelength conversion layer containing the non-conductive layered clay compound did not leak electricity and the metal reflection layer was less deteriorated. In particular, when a clay mineral having an electric conductivity of 80 μS / cm or less is used, a good LED device having a very high total luminous flux maintenance factor and little deterioration in light emission characteristics can be obtained.

Further, when a wavelength conversion layer is formed by applying a mixture of the phosphor dispersion liquid and the polysiloxane precursor-containing liquid (Examples 12, 13, and 15, and Comparative Example 8), the wavelength The adhesion between the conversion layer and the LED element or the metal reflection layer was high. Moreover, also when the polysiloxane precursor containing liquid was apply | coated and hardened on the cured film of fluorescent substance dispersion liquid (Example 14), the adhesiveness with an LED element and a metal reflective layer was high.
When polysiloxane is contained in the wavelength conversion layer (Examples 12 to 15 and Comparative Example 8), it is presumed that the phosphor, the inorganic oxide fine particles, and the layered clay compound are bound to increase the film strength. Furthermore, since the adhesion area between the wavelength conversion layer and the LED element or the metal reflection layer is increased, it is presumed that peeling at the interface with these layers hardly occurred.

In addition, when a sealing layer made of polysiloxane was formed on the wavelength conversion layer (Examples 14 and 15), the initial total luminous flux value increased. When the sealing layer is formed on the wavelength conversion layer, the unevenness on the surface of the wavelength conversion layer is smoothed by the sealing layer, so that it is presumed that the light extraction efficiency is increased.

Further, in the LED devices of Examples 1 to 11 and Comparative Examples 1 to 7 in which the wavelength conversion layer does not contain a binder (polysiloxane) and the sealing layer made of silicone resin is provided on the wavelength conversion layer, the heat shock test is performed. Even if I went there, it was hard to break. Since the silicone resin of the sealing layer enters the gap between the phosphors of the wavelength conversion layer and there is no clear interface between the wavelength conversion layer and the sealing layer, even if the temperature of the LED device changes, the wavelength conversion layer and the sealing layer It is presumed that there was little difference in expansion rate and contraction rate, and it was difficult to apply a load to the wire.
Furthermore, the phosphor dispersion containing the clay mineral having an electrical conductivity of 150 μS / cm or more showed very good sedimentation stability. It is considered that these clay minerals have an increased electrical affinity with the phosphor surface and suppress sedimentation of the phosphor.

The LED device of the present invention has high gas barrier properties and light extraction properties over a long period of time. Therefore, both can be applied to indoor and outdoor lighting devices.

DESCRIPTION OF SYMBOLS 1 Substrate 2 Metal reflective layer 3 LED element 4 Projection electrode 5 Wavelength conversion layer 6 Sealing layer 100 LED device

Claims

A method for manufacturing an LED device, comprising: a substrate; an LED element disposed on the substrate; a metal portion disposed on the substrate; and a wavelength conversion layer covering the LED element and the metal portion. ,
Preparing an LED package in which an LED element and a metal part are arranged on a substrate,
A wavelength conversion layer is formed by applying and curing a phosphor dispersion containing a phosphor, a non-conductive layered clay compound, inorganic oxide fine particles, and a solvent so as to cover the LED element and the metal part of the LED package. Form the
The said nonelectroconductive layered clay compound is a manufacturing method of the LED apparatus which is an electrical conductivity of the aqueous solution whose density | concentration of the said nonelectroconductive layered clay compound is 2 mass% becomes 500 microsiemens / cm or less.
2. The LED device according to claim 1, wherein the non-conductive layered clay compound is a compound having an electric conductivity of 10 to 80 μS / cm in an aqueous solution in which the concentration of the non-conductive layered clay compound is 2% by mass. Manufacturing method.
2. The LED device according to claim 1, wherein the non-conductive layered clay compound is a compound having an electric conductivity of 150 to 500 μS / cm in an aqueous solution in which the concentration of the non-conductive layered clay compound is 2% by mass. Manufacturing method.
The method for manufacturing an LED device according to any one of claims 1 to 3, wherein a sealing layer is further formed on the wavelength conversion layer.
The manufacturing method of the LED device of Claim 4 which apply | coats and hardens the resin composition containing a silicone resin or an epoxy resin, and forms a sealing layer on the said wavelength conversion layer.
The method for manufacturing an LED device according to any one of claims 1 to 5, wherein the non-conductive layered clay compound is a non-swellable layered clay compound.
The non-conductive layered clay compound is one or more compounds selected from the group consisting of muscovite, phlogopite, sericite, fluorine phlogopite, potassium tetrasilicon mica, and synthetic mica. The manufacturing method of the LED device as described in one term.
The method for manufacturing an LED device according to any one of claims 1 to 7, wherein the water absorption of the non-conductive layered clay compound is 0.2% by mass or more.
The method for manufacturing an LED device according to any one of claims 1 to 8, wherein the solvent contains alcohol.
The LED device manufacturing method according to any one of claims 1 to 9, wherein the phosphor dispersion contains a polysiloxane precursor.
10. The method for manufacturing an LED device according to claim 1, wherein a polysiloxane precursor is applied on a cured film of the phosphor dispersion liquid to form the wavelength conversion layer.
The method for manufacturing an LED device according to any one of claims 1 to 11, wherein the metal part is a metal reflective layer or a protruding electrode disposed on the substrate.
The method for manufacturing an LED device according to any one of claims 1 to 12, wherein the metal part includes silver.