JP2016154179A - Light-emitting device and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-emitting device which improves light extraction efficiency, and a manufacturing method thereof.SOLUTION: A light-emitting device 100 comprises: a substrate 1; a light-emitting element 2 which is disposed on the substrate; and a reflection layer 3 which is disposed around the light-emitting element while being spaced apart from an outer periphery of the light-emitting element and contains a binder and a reflection material. A distance between an end portion of the reflection layer closer to the light-emitting element and the outer periphery of the light-emitting element is 5 to 500 μm. The reflection layer includes: a film thickness inclined region (a) in which film thickness is increased from the end portion closer to the light-emitting element to an outer peripheral side of the light-emitting device; and a film thickness uniform region (b) which is positioned closer to the outer periphery of the light-emitting device than the film thickness inclined region and in which film thickness is uniform. An angle formed from a tangential line of the reflection layer in a portion of the film thickness inclined region having film thickness which is half of the film thickness in the film thickness uniform region, and the substrate is 15° to 80°.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light emitting device and a manufacturing method thereof.

  In recent years, a phosphor such as a YAG phosphor has been placed in the vicinity of a gallium nitride (GaN) blue LED (Light Emitting Diode) chip, and has received blue light and blue light emitted from the blue LED chip. An LED device that obtains white light by mixing yellow light emitted from a phosphor is widely used. In addition, various phosphors are arranged in the vicinity of the blue LED chip, and the blue light emitted from the blue LED chip and the red light and green light emitted from the phosphor receiving the blue light are mixed to obtain white light. Devices are also being developed.

  The white LED device has various uses, for example, there is a demand as a substitute for a fluorescent lamp or an incandescent lamp. Such an illuminating device has a configuration in which a plurality of white LED devices are combined, and how to increase the light extraction efficiency of each white LED device is important in realizing cost reduction and long life. come.

  The conventional LED device has a problem that the substrate on which the LED element is mounted easily absorbs the emitted light of the LED element and the fluorescence emitted by the phosphor, and the light extraction performance is not sufficient. Therefore, in a general LED device, a reflector having a high light reflectance is disposed around the LED element. Such a reflector is generally formed of metal plating or the like.

  However, a reflector made of metal plating cannot be formed on the entire surface of the substrate in order to prevent electrical conduction. Therefore, there is a problem that light is absorbed by the substrate in the region where the reflector is not formed.

  On the other hand, Patent Document 1 proposes a reflector in which a metal plating of a substrate is covered with a resin layer. Patent Document 2 proposes that a layer made of light diffusing particles and a ceramic binder be a reflector. Further, Patent Document 3 and Patent Document 4 show that a reflective member is provided on the outer peripheral side of the substrate; a cavity is provided in the substrate, and an inner wall of the substrate is used as a reflective surface.

JP 2005-136379 A International Publication No. 2014/017108 JP2013-89645A JP 2014-60343 A

  However, the technique disclosed in Patent Document 1 does not precisely control the positional relationship between the light emitting element and the reflective layer or the shape of the reflective layer. For this reason, it has been difficult for the technique to sufficiently increase the total luminous flux (brightness). Moreover, in the technique of patent document 2, the shape of the edge part by the side of the light emitting element of a reflection layer is not controlled. Therefore, the light emitted from the side surface of the light emitting element is easily reflected to the light emitting element side by the reflective layer, and is easily absorbed by the light emitting element. That is, it has been difficult to sufficiently increase the light extraction efficiency of the light emitting device.

  Furthermore, in the techniques of Patent Document 3 and Patent Document 4, since the gap between the light emitting element and the reflecting member is wide, the light may be absorbed by the substrate or the like before the light reaches the reflecting member. The light extraction efficiency could not be increased.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a light-emitting device with very good light extraction efficiency and a method for manufacturing the same.

The first of the present invention relates to a light emitting device shown below.
[1] A light emitting device comprising: a substrate; a light emitting element disposed on the substrate; and a reflective layer including a binder and a reflective material disposed around the light emitting element and spaced from the outer periphery of the light emitting element. The distance between the light emitting element side end of the reflective layer and the outer periphery of the light emitting element is 5 to 500 μm, and the reflective layer is directed from the light emitting element side end toward the outer peripheral side of the light emitting device. The film thickness in the film thickness gradient area includes a film thickness gradient area where the film thickness increases, and a film thickness uniform area located on the outer peripheral side of the light emitting device from the film thickness gradient area and having a uniform film thickness. The light-emitting device whose angle which the tangent of the said reflective layer of the location which has a film thickness of half the film thickness of a uniform area | region and the said board | substrate makes is 15-80 degrees.

[2] The light emitting device according to [1], wherein a distance between the light emitting element side end of the reflective layer and an outer periphery of the light emitting element is 10 to 300 μm.
[3] The light emitting device according to [1] or [2], wherein a film thickness of the uniform film thickness region of the reflective layer is 5 to 200 μm.
[4] The light emitting device according to any one of [1] to [3], wherein the reflective material is a white pigment.
[5] The light emitting device according to any one of [1] to [4], wherein the binder is polysiloxane.
[6] In [5], the polysiloxane includes a structure derived from at least one alkoxysilane compound selected from the group consisting of a bifunctional alkoxysilane compound, a trifunctional alkoxysilane compound, and a tetrafunctional alkoxysilane compound. The light-emitting device of description.
[7] The light emitting device according to any one of [1] to [6], wherein the reflective layer includes at least one of inorganic particles and clay mineral particles.
[8] The light emitting device according to any one of [1] to [7], wherein the light emitting element is an LED element that emits light from a side surface.

The second of the present invention relates to a method for manufacturing a light emitting device shown below.
[9] A method for producing a light-emitting device according to any one of [1] to [8], wherein a step of preparing a composition for forming a reflective layer including a binder precursor and the reflective material; The manufacturing method of a light-emitting device including the process of apply | coating the said composition for reflective layer formation to the circumference | surroundings of the area | region which arrange | positions the said light emitting element, and the process of arrange | positioning the said light emitting element on the said board | substrate.
[10] The step of applying the reflective layer forming composition is a step of applying the reflective layer forming composition from the region side where the light emitting element is disposed toward the outer peripheral side of the light emitting device. ] The manufacturing method of the light-emitting device of description.
[11] The method for manufacturing a light emitting device according to [9] or [10], wherein a step of arranging the light emitting element is performed before the step of applying the composition for forming a reflective layer.
[12] The method for manufacturing a light-emitting device according to [9] or [10], wherein a step of arranging the light-emitting element is performed after the step of applying the composition for forming a reflective layer.

[13] The method for producing a light-emitting device according to any one of [9] to [12], wherein the viscosity of the reflective layer forming composition measured at 25 ° C. with a vibration viscometer is 5 to 1000000 cP.
[14] The method for manufacturing a light-emitting device according to any one of [9] to [13], wherein the binder precursor is an alkoxysilane compound.
[15] The method for manufacturing a light emitting device according to any one of [9] to [14], wherein the composition for forming a reflective layer contains an organic solvent.
[16] The method for manufacturing a light-emitting device according to any one of [9] to [15], wherein the composition for forming a reflective layer includes at least one of a monohydric alcohol and a polyhydric alcohol.

  According to the present invention, a light emitting device having very good light extraction efficiency can be obtained.

(A) is a schematic sectional drawing which shows an example of the light-emitting device of this invention, (b) is a top view of the said light-emitting device. It is the schematic sectional drawing which expanded the reflective layer of the light-emitting device of this invention. It is a schematic sectional drawing which shows an example of the conventional light-emitting device. It is a schematic sectional drawing which shows the other example of the light-emitting device of this invention. It is a schematic sectional drawing which shows the other example of the light-emitting device of this invention.

  Hereinafter, the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and various modifications can be made without departing from the scope of the invention.

1. Light-emitting device An example of the light-emitting device of the present invention is shown in FIG. FIG. 1A is a schematic cross-sectional view of an example of the light emitting device of the present invention, and FIG. 1B is a top view of the light emitting device. The light emitting device 100 of the present invention includes a substrate 1, a light emitting element 2 disposed on the substrate 1, and a reflective layer 3 formed around the light emitting element 2. The reflective layer 3 is a layer for reflecting the light emitted from the light emitting element 2 and the fluorescence emitted from the phosphor in the wavelength conversion layer 4 to the light extraction surface side of the light emitting device 100. Here, the light emitting device 100 of the present invention may include the wavelength conversion layer 4, a light transmitting layer (not shown), and the like.

  Here, in the conventional light emitting device, the reflective layer is often in contact with the side surface of the light emitting element, and in this case, there is a problem that light cannot be extracted from the side surface of the light emitting element. Therefore, as shown in FIG. 3, it is considered to provide a gap between the reflective layer 3 and the light emitting element 2. However, in the conventional light emitting device, the angle formed by the end of the reflective layer 3 on the light emitting element 2 side and the substrate 1 (the angle represented by α in FIG. 3) is large. Therefore, even if a gap is provided between the reflective layer 3 and the light emitting element 2, the light emitted from the light emitting element 2 is easily reflected to the light emitting element 2 side by the reflective layer 3 and easily absorbed by the light emitting element 2. . That is, it is difficult to increase the light extraction efficiency of the light emitting device 200.

  On the other hand, in the light emitting device 100 of the present invention, as shown in FIGS. 1A and 1B, the reflective layer 3 is not only formed with a gap from the outer periphery of the light emitting element 2. The film thickness of the reflective layer 3 is formed so as to increase from the light emitting element 2 side end toward the outer peripheral side of the light emitting device 100 (in FIG. 1A, the film thickness gradient region represented by a. ). That is, the shape of the reflective layer 3 is controlled so that the light emitted from the side surface of the light emitting element 2 and reflected by the reflective layer 3 travels not to the light emitting element 2 side but to the light extraction surface side of the light emitting device 100. Yes. On the other hand, the film thickness of the reflective layer 3 is uniformly formed on the outer peripheral side from the film thickness gradient area a (the film thickness uniform area represented by b in FIG. 1A). In the film thickness uniform region b, light traveling from the wavelength conversion layer 4 side to the substrate 1 side is efficiently reflected to the light extraction surface side. Therefore, the light emitting device 100 of the present invention has a very high light extraction efficiency.

  Hereinafter, the light emitting device of the present invention will be described by taking an LED device in which the light emitting element is an LED element as an example, but the light emitting device of the present invention is not limited thereto.

1-1. Substrate The substrate is a member that supports the light emitting element, and the shape of the substrate is not particularly limited. For example, as shown in FIG. 1A, a cavity (concave portion) may be provided, or a flat plate shape may be used. The shape of the cavity is not particularly limited. For example, as shown in FIG. 1, a truncated cone shape, a truncated pyramid shape, a columnar shape, a prismatic shape, or the like may be used.

  The substrate 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 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. For example, if the substrate is white, even if the substrate is partially exposed, light is hardly absorbed in the region, and the light extraction efficiency from the light emitting device is likely to increase.

  As shown in FIG. 1, a metal wiring 11 is usually disposed on the substrate 1. The metal wiring 11 is made of a metal such as silver, and can be a pair of metal electrode portions that electrically connect an external power source (not shown) and the LED element 2. The board | substrate which has metal wiring is produced by a general method, for example, is obtained by integrally molding resin and a metal plate.

1-2. LED element (light emitting element)
The LED element is electrically connected to a metal wiring disposed on the substrate and emits light of a specific wavelength. The wavelength of the light emitted from the LED element is not particularly limited. The LED element 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 is not particularly limited. When the LED element is an element that emits blue light, the LED element includes an n-GaN compound semiconductor layer (cladding layer), an InGaN compound semiconductor layer (light emitting layer), and a p-GaN compound semiconductor layer (cladding layer). Layer) and a transparent electrode layer. The LED element may have a light emitting surface (upper surface) of, for example, 200 to 300 μm × 200 to 300 μm. Moreover, the height of an LED element is about 50-200 micrometers normally.

  The LED element may emit light only from the upper surface, or may emit light from the upper surface and side surfaces. Also, light may be emitted from the back surface. Further, in the light emitting device 100 shown in FIG. 1, only one light emitting element (LED element) 2 is arranged on the substrate 1, but a plurality of light emitting elements (LED elements) 2 are arranged on the substrate 1. Also good.

  The connection method between the LED element and the metal wiring disposed on the substrate is not particularly limited. For example, as shown in FIG. 1, the LED element 2 and the metal wiring 11 may be connected via a protruding electrode 12 or the like. Further, for example, the LED element and the metal wiring may be connected via a metal wire or the like. A mode in which the LED element and the metal wiring are connected via a protruding electrode is referred to as a flip chip type, and a mode in which the LED element and the metal wiring are connected via a wire is referred to as a wire bonding type.

1-3. Reflective layer The reflective layer is a layer that reflects the light emitted from the LED element and the fluorescence emitted from the phosphor particles contained in the wavelength conversion layer described later to the light extraction surface side of the LED device. By disposing the reflective layer, the amount of light extracted from the LED device increases.

  The reflective layer includes at least a binder and a reflective material. The binder contained in the reflective layer can be a transparent resin or a translucent ceramic. The transparent resin can be, for example, a silicone resin and an epoxy resin. On the other hand, the translucent ceramic may be a cured product (polysiloxane or the like) of an alkoxysilane compound.

  The reflective material is a particle having an average primary particle size larger than 100 nm and 20 μm or less, and a d-line (light with a wavelength of 587.96 nm) reflectance of 1.6 or more. The type and content of the binder and the reflective material contained in the reflective layer will be described in detail in the light emitting device manufacturing method described later. The reflective layer may contain inorganic particles, clay mineral particles, silane coupling agents, and the like as necessary.

  Here, the reflective layer is usually provided on the substrate. In the light emitting device of the present invention, the reflective layer is formed with a predetermined gap from the outer peripheral portion of the LED element. Specifically, the gap between the light emitting element (LED element) side end of the reflective layer and the outer periphery of the LED element is 5 to 500 μm, the gap is preferably 10 to 300 μm, and more preferably 20 to 250 μm. is there. The light emitting element (LED element) side end of the reflective layer is the inner periphery of the reflective layer when the light emitting device is observed from the upper surface (light extraction surface). On the other hand, the outer periphery of the LED element is the outer periphery of the LED element when the light emitting device is observed from the upper surface (light extraction surface). The distance between the light emitting element (LED element) side end of the reflective layer and the outer peripheral part of the LED element is the light emitting element (LED element) side of the reflective layer when the light emitting device is observed from the upper surface (light extraction surface). The distance between the end and the outer periphery of the LED element. In the present invention, the distance between the outer periphery of the light emitting element and the end of the light emitting element of the reflective layer may not be constant over the entire outer periphery of the light emitting element. However, from the viewpoint of light extraction efficiency, the distance is the entire outer periphery of the light emitting element. In this case, it is preferable to be within the above-mentioned range. Further, as shown in FIG. 1B, it is particularly preferable that the distance is constant.

  When the gap is 5 μm or more, light emitted from the side surface of the LED element is easily emitted to the light extraction surface side. On the other hand, if the gap is too wide, the formation area of the reflective layer becomes relatively small. That is, the area of the region where the substrate, the metal wiring, or the like is exposed increases, and light is absorbed by these regions, so that the light extraction efficiency may be reduced. However, if the gap is 500 μm or less, the amount of light absorbed by the substrate or the like can be reduced. The method for specifying the gap is not particularly limited, but can be specified by observing the light emitting device from the light extraction surface side or by observing the cut surface when cut perpendicular to the substrate.

  In addition, as shown in FIG. 1A, the reflective layer has a film thickness gradient region a where the film thickness increases from the light emitting element (LED element) side end toward the outer peripheral side of the light emitting device 100, and the film thickness. It has a uniform film thickness region b which is located on the outer peripheral side of the light emitting device 100 from the inclined region a and has a uniform film thickness. In the film thickness inclined region a, the film thickness may increase intermittently, but it is preferable that the film thickness increases continuously from the viewpoint of light extraction efficiency.

  Here, in the light emitting device of the present invention, the degree of film thickness inclination in the film thickness inclination area a of the reflective layer is controlled. Specifically, as shown in the schematic cross-sectional view of FIG. 2 (enlarged view of the reflective layer 2), the thickness t2 is half of the thickness t1 of the uniform thickness region b in the thickness gradient region a. The angle formed between the tangent L of the point p and the substrate 1 (angle represented by α in FIG. 2) is 15 to 80 °, preferably 15 to 75 °, and more preferably 20 to 70 °. is there. The larger the angle α, the steeper the film thickness gradient. In the light emitting device of the present invention, since the angle α is 80 ° or less, the light emitted from the side surface of the light emitting device 2 can be sufficiently reflected to the light extraction surface side of the light emitting device 100. On the other hand, when the angle formed by the substrate 1 and the tangent L is too small, the area of the film thickness gradient region a with respect to the entire area of the reflective layer 3 is widened. That is, the area of the film thickness inclined region a having a relatively small film thickness becomes excessively large, and the light reflectivity by the reflective layer 3 is difficult to increase. On the other hand, when the angle formed between the substrate 1 and the tangent L is 15 ° or more, the area of the film thickness inclined region a is within an appropriate range, and the reflection layer 3 can sufficiently reflect light. Here, the total area of the film thickness gradient region a is preferably 5% or more, more preferably 10% or more with respect to the total area of the reflective layer.

  The angle can be specified by observing a cut surface when the light emitting device 100 is cut perpendicularly to the substrate 1. The inclination of the film thickness gradient region a of the reflective layer 3 can be adjusted by adjusting the viscosity of the composition for forming a reflective layer described later, adjusting the surface tension of the composition for forming a reflective layer, or in the composition for forming a reflective layer. It can adjust suitably by adjusting the quantity and kind of organic solvent contained, adjusting solid content concentration, etc. Moreover, it can adjust also with the application | coating method of the composition for reflective layer formation.

  Here, it is preferable that the film thickness of the reflective layer 3 in a film thickness uniform area | region is 5-200 micrometers, More preferably, it is 20-150 micrometers, More preferably, it is ~ 100 micrometers. When the film thickness in the uniform film thickness region is 20 μm or more, the reflectance of the reflective layer 3 tends to increase. On the other hand, if the thickness of the reflective layer 3 is too thick, cracks or the like are likely to occur in the reflective layer 3. In a general light emitting device, if the thickness of the reflective layer is excessively large, it is difficult to extract light from the LED element. However, in the present invention, since the reflective layer has a film thickness gradient region, even if the reflective layer is thick. , Can extract light efficiently.

  Further, as shown in FIG. 1, when the substrate 1 has a cavity, the reflective layer 3 may be formed only on the bottom surface of the cavity. Further, as shown in FIG. 4, the reflective layer 3 may be formed on the side surface 6 and the bottom surface of the cavity. When the reflective layer 3 is formed on the inner wall surface 6 of the cavity, the light traveling in the horizontal direction on the surface of the wavelength conversion layer 4 can be reflected and extracted by the reflective layer 3, and the light extraction performance is further improved. Furthermore, the reflective layer of the light emitting device of the present invention only needs to include the above-described film thickness gradient region and film thickness uniform region. For example, as shown in FIG. The area | region where thickness of 3 becomes thin may be included.

1-4. Wavelength Conversion Layer The light emitting device of the present invention may include a wavelength conversion layer, and the wavelength conversion layer includes phosphor particles and a binder. The phosphor particles receive light (excitation light) emitted from the LED element and emit fluorescence. By mixing the excitation light and the fluorescence, the color of the light from the LED device becomes a desired color. For example, when the light from the LED element is blue and the fluorescence emitted from the phosphor contained in the wavelength conversion layer is yellow, the light from the LED device is white.

  The wavelength conversion layer only needs to cover at least the LED element. For example, as shown in FIG. 1, the wavelength conversion layer may cover the reflective layer 3 and the metal wiring 11 together with the LED element 2. For example, as shown in FIG. 5, only the LED element 2 may be covered.

  The phosphor particles contained in the wavelength conversion layer may be anything that is excited by light emitted from the LED element and emits fluorescence having a wavelength different from that of the emitted light from the LED element. For example, examples of phosphor particles 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 particles are, for example, 1) A suitable 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. . The mixed raw material having a predetermined composition can be obtained by mixing 1) a solution in which rare earth elements of Y, Gd, Ce, and Sm are dissolved in an acid with a stoichiometric ratio and oxalic acid to obtain a coprecipitated oxide. 2) It can also be obtained by mixing this coprecipitated oxide with aluminum oxide or gallium oxide.

  The type 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 particles is preferably 1 μm to 50 μm, and more preferably 10 μm or less. The larger the particle size of the phosphor particles, the higher the light emission efficiency (wavelength conversion efficiency). On the other hand, when the particle diameter of the phosphor particles is too large, a gap generated at the interface between the phosphor particles and the binder becomes large. Thereby, the intensity | strength of the cured film of a wavelength conversion layer tends to fall. The average particle diameter of the phosphor particles 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 binder contained in the wavelength conversion layer may be a transparent resin or a translucent ceramic. The transparent resin can be, for example, a silicone resin and an epoxy resin. When the binder is a transparent resin, the film thickness of the wavelength conversion layer is preferably about 25 μm to 5 mm. When the film thickness of the wavelength conversion layer is too thick, the concentration of the phosphor particles becomes excessively low, and the phosphor particles may not be uniformly dispersed. The film thickness of the wavelength conversion layer means the maximum film thickness of the wavelength conversion layer formed on the light emitting surface of the LED element. The film thickness of the wavelength conversion layer can be measured with a laser holo gauge. When the binder is a transparent resin, the amount of phosphor particles contained in the wavelength conversion layer is generally 5 to 15% by mass.

  On the other hand, the translucent ceramic may be a cured product (polysiloxane or the like) of an alkoxysilane compound. When the binder is a translucent ceramic, the film thickness of the wavelength conversion layer is preferably 5 to 200 μm. When the binder is a translucent ceramic, if the wavelength conversion layer is excessively thick, cracks and the like are likely to occur in the wavelength conversion layer. Even when the binder is a translucent ceramic, the film thickness of the wavelength conversion layer means the maximum film thickness of the wavelength conversion layer formed on the light emitting surface of the LED element. The film thickness of the wavelength conversion layer can be measured with a laser holo gauge.

  Moreover, when a binder is a translucent ceramic, it is preferable that the quantity of the fluorescent substance particle contained in a wavelength conversion layer is 60-95 mass%. The higher the concentration of the phosphor particles contained in the wavelength conversion layer, the better. When the concentration of the phosphor particles is high, the strength of the wavelength conversion layer tends to increase. However, if the content ratio of the translucent ceramic is too small, the phosphor particles may not be sufficiently retained.

1-5. Light Transmitting Layer The light emitting device of the present invention may include a light transmitting layer 5 as shown in FIG. The translucent layer 5 functions to protect the LED element 2 from external impacts, gases, and the like. The light-transmitting layer includes a light-transmitting material (hereinafter also referred to as “translucent material”). The translucent material may be a transparent resin or a translucent ceramic.

  When the translucent material is a transparent resin, the transparent resin can be, for example, a silicone resin and an epoxy resin. In this case, the thickness of the translucent layer is usually preferably 25 μm to 5 mm, and more preferably 1 to 3 mm. Generally, it is difficult to make the film thickness of the translucent layer containing the transparent resin 25 μm or less. On the other hand, from the viewpoint of miniaturization of the LED device, the film thickness of the translucent layer is preferably 5 mm or less. The film thickness of the light transmissive layer means the maximum film thickness of the light transmissive layer formed on the light emitting surface of the LED element. The film thickness of the translucent layer can be measured with a laser holo gauge.

  On the other hand, when the translucent material is a translucent ceramic, the translucent ceramic can be a cured product (polysiloxane or the like) of an alkoxysilane compound. In this case, it is preferable that the film thickness of a translucent layer is 0.5-10 micrometers. If the film thickness of the light-transmitting layer is less than 0.5 μm, the effect of protecting the LED element from external impact, gas, or the like may not be sufficiently obtained. On the other hand, if the film thickness of the translucent layer exceeds 10 μm, cracks may occur in the translucent layer. Even when the translucent material is ceramic, the film thickness of the translucent layer means the maximum film thickness of the translucent layer formed on the light emitting surface of the LED element. The film thickness of the translucent layer is measured with a laser holo gauge.

2. Method for Manufacturing Light-Emitting Device The method for manufacturing the above-described light-emitting device can be a method including the following three steps.
a) Step of preparing a composition for forming a reflective layer containing a binder precursor and the reflective material b) Step of applying the composition for forming a reflective layer around a region where the light emitting element is arranged c) Step of Disposing the Light Emitting Element on the Substrate Here, any of the steps b) and c) may be performed first.

  However, the method for manufacturing the above-described light emitting device is not limited to the manufacturing method including the above steps. For example, there may be a method in which only the steps a) and b) are performed by preparing a substrate in which the light emitting elements are connected to the electrodes in advance without performing the c) light emitting element arranging step. If necessary, d) a step of forming a wavelength conversion layer, and e) a light-transmitting layer forming step of forming a light-transmitting layer so as to cover the light emitting element may be performed.

2-1. Preparation Step of Reflective Layer Forming Composition The reflective layer forming composition for obtaining the aforementioned reflective layer includes a reflective layer forming composition containing a binder precursor, a reflective material, and a solvent. The reflective layer forming composition may contain inorganic particles, clay mineral particles, silane coupling agents, and the like, if necessary.

2-1-1. Binder precursor The binder precursor contained in the composition for forming a reflective layer is not particularly limited as long as it is a compound that can be cured by drying or reaction to sufficiently bind the reflective material. As described above, the binder of the reflective layer may be a transparent resin or a translucent ceramic. When the above-mentioned binder is a transparent resin, the binder precursor may be, for example, a silicone resin, an epoxy resin, or a precursor thereof.

  On the other hand, when the above-mentioned binder is a translucent ceramic, the binder precursor may be, for example, an alkoxysilane compound. The alkoxysilane compound may be a bifunctional alkoxysilane, a trifunctional alkoxysilane, and a tetrafunctional alkoxysilane monomer or oligomer thereof. The alkoxysilane compound may contain only one kind or two or more kinds. The alkoxysilane compound is hydrolyzed and polycondensed into a polysiloxane when the reflective layer forming composition is cured. The alkoxysilane compound is preferably an oligomer in which several to several tens of monomers are polymerized. When the alkoxysilane compound is an oligomer, shrinkage is reduced when the reflective layer forming composition is cured, and cracks are less likely to occur when the reflective layer is formed.

  Moreover, if the binder (polysiloxane) of the obtained reflective layer contains a lot of structures derived from bifunctional alkoxysilane, the flexibility of the reflective layer is likely to increase. However, heat resistance tends to decrease. On the other hand, when many structures derived from tetrafunctional alkoxysilane are contained, although the heat resistance is increased, the crack resistance tends to be lowered. Therefore, in the light emitting device of the present invention, the composition ratio of the bifunctional to tetrafunctional alkoxysilane compound is appropriately selected according to the desired characteristics of the reflective layer.

  The ratio of the bifunctional alkoxysilane compound, the trifunctional alkoxysilane compound, and the tetrafunctional alkoxysilane compound to the total amount of the alkoxysilane compound in the reflective layer forming composition is such that the reflective layer forming composition is dried and solidified at 150 ° C. It can obtain | require from the spectrum of the solid Si-NMR of the sample obtained by this, respectively.

The spectrum of solid-state Si-NMR (Nuclear Magnetic Resonance) will be described. The tetrafunctional alkoxysilane compound polymer (polysiloxane) is represented by the SiO ₂ · nH ₂ O characteristic formula, but structurally, oxygen atoms O are bonded to the apexes of the silicon atom Si tetrahedron. These silicon atoms have a structure in which silicon atoms Si are further bonded to these oxygen atoms O and spread in a net shape.

The schematic diagrams (A) and (B) below represent the Si—O net structure, ignoring the tetrahedral structure. The schematic diagram (A) shows a case where each oxygen atom O is bonded to another Si atom in the Si—O net structure. On the other hand, the schematic diagram (B) shows a case where part of the oxygen atom O is replaced with another member (here, -H) in the Si-O net structure. The Si atom derived from the tetrafunctional alkoxysilane compound includes four atoms (Q ⁴ ) bonded to —OSi as shown in the schematic diagram (A), and three Si atoms as shown in the schematic diagram (B). There is an atom (Q ³ ) or the like bonded to —OSi. In the solid-state Si-NMR spectrum, these are observed as different peaks. Then, a peak based on the silicon atoms derived from the tetrafunctional alkoxysilane compound, are collectively referred to as Q sites, the peak derived from each atom, Q ⁴ peak, Q ³ peak, called .... In the present specification, each peak of Q ^{0 to} Q ⁴ derived from the Q site is referred to as a Q ⁿ peak group. The Q ⁿ peak group of the silica film containing no organic substituent is usually observed as a multimodal peak continuous in the region of chemical shift of −80 to −130 ppm.

On the other hand, a silicon atom (that is, silicon derived from a trifunctional alkoxysilane compound) in which three oxygen atoms are bonded and one non-oxygen atom (usually carbon) is bonded is generally referred to as a T site. Is done. The peak derived from the T site is observed as each peak of T ^{0 to} T ³ as in the case of the Q site. In this specification, each peak derived from the T site is referred to as a ^Tn peak group. The T ⁿ peak group is generally observed as a multimodal peak continuous in the region on the higher magnetic field side (usually chemical shift −80 to −40 ppm) than the Q ⁿ peak group.

Furthermore, a silicon atom (that is, silicon derived from a bifunctional alkoxysilane compound) in which two oxygen atoms are bonded and two atoms other than oxygen (usually carbon) are bonded is generally referred to as a D site. Is done. Similarly to the peak group derived from the Q site and the T site, the peak derived from the D site is also observed as each peak of D ^{0 to} D ⁿ (D ⁿ peak group), and further from the peak group of Q ⁿ and T ^n. It is observed as a multimodal peak in the region on the high magnetic field side (usually the region with a chemical shift of −3 to −40 ppm).

Then, D ⁿ observed in solid ^Si-NMR, T ^n, mutual area ratio of each peak group Q ^n, the molar ratio and the respective equal of silicon atoms placed in an environment corresponding to each peak group. Therefore, the ratio of the area of each peak group to the total area of the Q ⁿ peak group, the T ⁿ peak group, and the D ⁿ peak group is the total amount of alkoxysilane compounds in the reflective layer forming composition (total moles of silicon atoms). The molar ratio of each alkoxysilane compound (a tetrafunctional alkoxysilane compound, a trifunctional alkoxysilane compound, and a bifunctional alkoxysilane compound) with respect to the amount) is equal.

Examples of the tetrafunctional alkoxysilane compound include compounds represented by the following general formula (IV).
Si (OR ¹ ) ₄ (IV)
In the general formula (IV), each R ¹ independently represents an alkyl group or a phenyl group, and preferably represents an alkyl group having 1 to 5 carbon atoms or a phenyl group.

  Specific examples of tetrafunctional alkoxysilane compounds include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, tetrapentyloxysilane, tetraphenyloxysilane, trimethoxymonoethoxysilane, dimethoxydiethoxysilane, and triethoxymono. Methoxysilane, trimethoxymonopropoxysilane, monomethoxytributoxysilane, monomethoxytripentyloxysilane, monomethoxytriphenyloxysilane, dimethoxydipropoxysilane, tripropoxymonomethoxysilane, trimethoxymonobutoxysilane, dimethoxydibutoxysilane , Triethoxymonopropoxysilane, diethoxydipropoxysilane, tributoxymonopropoxysilane, dimethoxymonoethoxymolybdenum Butoxysilane, diethoxymonomethoxymonobutoxysilane, diethoxymonopropoxymonobutoxysilane, dipropoxymonomethoxymonoethoxysilane, dipropoxymonomethoxymonobutoxysilane, dipropoxymonoethoxymonobutoxysilane, dibutoxymonomethoxymonoethoxysilane , Alkoxysilanes such as dibutoxymonoethoxymonopropoxysilane, monomethoxymonoethoxymonopropoxymonobutoxysilane, aryloxysilane, and the like. Among these, tetramethoxysilane and tetraethoxysilane are preferable.

Examples of the trifunctional alkoxysilane compound include a compound represented by the following general formula (III).
R ² Si (OR ³ ) ₃ (III)
In said general formula, R < ³ > represents an alkyl group or a phenyl group each independently, Preferably a C1-C5 alkyl group or a phenyl group is represented. R ² represents a hydrogen atom or an alkyl group.

Specific examples of the trifunctional alkoxysilane compound include trimethoxysilane, triethoxysilane, tripropoxysilane, tripentyloxysilane, triphenyloxysilane, dimethoxymonoethoxysilane, diethoxymonomethoxysilane, dipropoxymonomethoxysilane, Dipropoxymonoethoxysilane, dipentyloxylmonomethoxysilane, dipentyloxymonoethoxysilane, dipentyloxymonopropoxysilane, diphenyloxylmonomethoxysilane, diphenyloxymonoethoxysilane, diphenyloxymonopropoxysilane, methoxyethoxypropoxysilane, monopropoxydimethoxy Silane, monopropoxydiethoxysilane, monobutoxydimethoxysilane, monopentyloxydiethoxysilane Monohydrosilane compounds such as monophenyloxydiethoxysilane; methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltripentyloxysilane, methylmonomethoxydiethoxysilane, methylmonomethoxydipropoxysilane, methylmonomethoxy Monomethylsilane compounds such as dipentyloxysilane, methylmonomethoxydiphenyloxysilane, methylmethoxyethoxypropoxysilane, methylmonomethoxymonoethoxymonobutoxysilane; ethyltrimethoxysilane, ethyltripropoxysilane, ethyltripentyloxysilane, ethyltriphenyl Oxysilane, ethyl monomethoxydiethoxysilane, ethyl monomethoxydipropoxysilane, ethyl monomethoxydipen Monoethylsilane compounds such as ruoxysilane, ethylmonomethoxydiphenyloxysilane, ethylmonomethoxymonoethoxymonobutoxysilane; propyltrimethoxysilane, propyltriethoxysilane, propyltripentyloxysilane, propyltriphenyloxysilane, propylmonomethoxydi Monopropylsilane compounds such as ethoxysilane, propylmonomethoxydipropoxysilane, propylmonomethoxydipentyloxysilane, propylmonomethoxydiphenyloxysilane, propylmethoxyethoxypropoxysilane, propylmonomethoxymonoethoxymonobutoxysilane; butyltrimethoxysilane, Butyltriethoxysilane, Butyltripropoxysilane, Butyltripentyloxysilane, Butylto Monophenyl such as Riphenyloxysilane, Butylmonomethoxydiethoxysilane, Butylmonomethoxydipropoxysilane, Butylmonomethoxydipentyloxysilane, Butylmonomethoxydiphenyloxysilane, Butylmethoxyethoxypropoxysilane, Butylmonomethoxymonoethoxymonobutoxysilane A butylsilane compound is included. Among these, a trifunctional alkoxysilane compound in which R ² represented by the general formula (III) is a methyl group is preferable. Specifically, methyltrimethoxysilane, methyltriethoxysilane, and the like are preferable, and methyltrimethoxysilane is particularly preferable.

Examples of the bifunctional alkoxysilane compound include compounds represented by the following general formula (II).
R ⁴ ₂ Si (OR ⁵ ) ₂ (II)
In the general formula (II), R ⁵ each independently represents an alkyl group or a phenyl group, preferably an alkyl group or a phenyl group, having 1 to 5 carbon atoms. R ⁴ represents a hydrogen atom or an alkyl group.

  Specific examples of the bifunctional alkoxysilane compound include dimethoxysilane, diethoxysilane, dipropoxysilane, dipentyloxysilane, diphenyloxysilane, methoxyethoxysilane, methoxypropoxysilane, methoxypentyloxysilane, methoxyphenyloxysilane, ethoxy Propoxysilane, ethoxypentyloxysilane, ethoxyphenyloxysilane, methyldimethoxysilane, methylmethoxyethoxysilane, methyldiethoxysilane, methylmethoxypropoxysilane, methylmethoxypentyloxysilane, methylmethoxyphenyloxysilane, ethyldipropoxysilane, ethyl Methoxypropoxysilane, ethyldipentyloxysilane, ethyldiphenyloxysilane, propyldimethoxysila , Propylmethoxyethoxysilane, propylethoxypropoxysilane, propyldiethoxysilane, propyldipentyloxysilane, propyldiphenyloxysilane, butyldimethoxysilane, butylmethoxyethoxysilane, butyldiethoxysilane, butylethoxypropoxysilane, butyldipropoxysilane , Butylmethyldipentyloxysilane, butylmethyldiphenyloxysilane, dimethyldimethoxysilane, dimethylmethoxyethoxysilane, dimethyldiethoxysilane, dimethyldipentyloxysilane, dimethyldiphenyloxysilane, dimethylethoxypropoxysilane, dimethyldipropoxysilane, diethyldimethoxysilane , Diethylmethoxypropoxysilane, diethyldiethoxysilane, Ethylethoxypropoxysilane, dipropyldimethoxysilane, dipropyldiethoxysilane, dipropyldipentyloxysilane, dipropyldiphenyloxysilane, dibutyldimethoxysilane, dibutyldiethoxysilane, dibutyldipropoxysilane, dibutylmethoxypentyloxysilane, dibutylmethoxy Phenyloxysilane, methylethyldimethoxysilane, methylethyldiethoxysilane, methylethyldipropoxysilane, methylethyldipentyloxysilane, methylethyldiphenyloxysilane, methylpropyldimethoxysilane, methylpropyldiethoxysilane, methylbutyldimethoxysilane, methyl Butyldiethoxysilane, methylbutyldipropoxysilane, methylethylethoxypropoxysilane , Ethylpropyldimethoxysilane, ethylpropylmethoxyethoxysilane, dipropyldimethoxysilane, dipropylmethoxyethoxysilane, propylbutyldimethoxysilane, propylbutyldiethoxysilane, dibutylmethoxyethoxysilane, dibutylmethoxypropoxysilane, dibutylethoxypropoxysilane, etc. Is included. Of these, dimethoxysilane, diethoxysilane, methyldimethoxysilane, and methyldiethoxysilane are preferable.

  Moreover, the oligomer of each said alkoxysilane monomer is obtained by mixing an alkoxysilane monomer by a desired ratio and making it react in presence of a well-known catalyst, water, and a solvent. The molecular weight of the oligomer is adjusted by the reaction time, temperature, catalyst, water concentration, and the like.

  The oligomer preferably has a weight average molecular weight of 500 to 20000 as measured by GPC (gel permeation chromatograph), more preferably 1000 to 10000, and further preferably 1500 to 6000. If the degree of polymerization of the oligomer is too high, the viscosity of the reflective layer forming composition may become excessively high, or the alkoxysilane compound may precipitate in the reflective layer forming composition.

  Here, the total amount of the binder precursor contained in the reflective layer forming composition is 5 to 40% by mass with respect to the total mass of components other than the solvent (organic solvent and water) contained in the reflective layer forming composition. It is preferable that it is 10-30 mass%. When the total amount of the binder precursor is less than 5% by mass, the reflective material is hardly sufficiently bound in the obtained reflective layer. As a result, powder is easily generated on the surface of the reflective layer. On the other hand, when the total amount of the alkoxysilane compound exceeds 40% by mass, the amount of the reflective material is relatively reduced, and the light reflectivity of the reflective layer tends to be low.

2-1-2. Reflective material The reflective material contained in the composition for forming a reflective layer plays a role of reflecting light emitted from the light emitting element in the reflective layer. In the present invention, the reflective material is a particle having an average primary particle size of greater than 100 nm and 20 μm or less, and a refractive index of light of d-line (wavelength: 587.96 nm) of 1.6 or more. The average primary particle size of the reflective material is preferably greater than 100 nm and 10 μm or less, and more preferably 200 nm to 2.5 μm. The “average primary particle diameter” in the present invention refers to D50 (median diameter) 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 reflective material can be, for example, a white pigment. Examples of reflective materials include barium carbonate, barium sulfate, zinc oxide, magnesium oxide, calcium oxide, titanium oxide, aluminum oxide, zirconium oxide, zinc sulfide, aluminum hydroxide, boron nitride, aluminum nitride, potassium titanate, titanate Barium, aluminum titanate, strontium titanate, calcium titanate, magnesium titanate, hydroxyapatite, and the like are included. The reflective material is particularly preferably titanium oxide, aluminum oxide, barium sulfate, zinc oxide, and boron nitride.

  When boron nitride is contained in the reflective material, the thermal conductivity of the resulting reflective layer is increased. As a result, the heat generated from the light emitting element can be quickly released from the substrate. Therefore, the temperature of the light emitting device can be kept low, and the device life can be extended.

  The amount of the reflective material contained in the composition for forming a reflective layer is preferably 50 to 95% by mass, more preferably 60 to 95% by mass of the solid content after heat curing of the composition for forming a reflective layer. It is 95 mass%, More preferably, it is 70-90 mass%. When the amount of the reflective material is 50% by mass or more, the light reflectivity of the obtained reflective layer is likely to be sufficiently increased. On the other hand, if the content of the reflective material is 95% by mass or less, the amount of the binder is relatively increased, and the reflective material is likely to be sufficiently bound. The mass of the solid content after heat curing of the composition for forming a reflective layer is the mass of a cured product obtained by curing the composition for forming a reflective layer at 150 ° C. for 1 hour. On the other hand, the amount of the reflective material is specified by the blending amount at the time of preparing the composition for forming a reflective layer, and EDX and XRD analysis. EDX and XRD analyzes are performed as follows. Specifically, (1) the component of the reflective layer forming composition after baking at 150 ° C. for 1 hour is subjected to component analysis by EDX, and the ratio by element is calculated from the contrast of the SEM photograph. (2) The structure is analyzed by XRD analysis, and the type of the reflective material is specified. Thereby, the kind of reflective material and its content are specified.

2-1-3. Solvent The solvent contained in the composition for forming a reflective layer includes water or an organic solvent. Any organic solvent that is compatible with the aforementioned alkoxysilane compound and that can uniformly disperse the reflective material or the like may be used. Examples of such organic solvents include monohydric alcohols, dihydric or higher polyhydric alcohols, ester solvents and the like.

  Examples of monohydric alcohols include methanol, ethanol, propanol, butanol and the like. The polyhydric alcohol may be either a diol or a triol. Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, diethylene glycol, glycerin, 1,3-butanediol, 1,4-butanediol, and preferably ethylene glycol, propylene glycol, 1,3-butane. Diol, 1,4-butanediol and the like are included. Examples of the ester solvent include methyl-3-methoxypropionate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate and the like.

  In particular, the organic solvent preferably contains at least one of a monohydric alcohol and a polyhydric alcohol.

  Moreover, when water and clay mineral particles are contained in the reflective layer forming composition, water enters between the layers of the clay mineral particles, the clay mineral particles swell, and the viscosity of the coating liquid tends to increase. The water content is preferably 0 to 30% by mass and more preferably 0 to 20% by mass with respect to the entire solvent.

  The total amount of the solvent contained in the reflective layer forming composition is preferably 10 to 45% by mass, and more preferably 20 to 40% by mass with respect to the total amount of the reflective layer forming composition. If the total amount of the solvent is excessively small, the fluidity of the composition for forming a reflective layer becomes too low and the coating stability tends to decrease. On the other hand, if the total amount of the solvent is excessively large, the volume change before and after curing becomes too large.

2-1-4. Inorganic particles The composition for forming a reflective layer may further contain inorganic particles. The inorganic particles are particles made of an inorganic material other than the above-described reflective material. The inorganic particles can be, for example, metal oxide fine particles having an average particle size of 5 nm or more and less than 100 nm. When the metal oxide fine particles are contained in the composition for forming a reflective layer, fine irregularities are generated on the surface of the resulting reflective layer, and an anchor effect is easily exhibited between the reflective layer and other layers. Moreover, when metal oxide microparticles | fine-particles etc. are contained in the composition for reflective layer formation, the stress which arises in a film | membrane at the time of polycondensation of an alkoxysilane compound will be relieve | moderated, and it will become difficult to produce a crack in the obtained reflective layer.

  The type of metal oxide fine particles is not particularly limited, but is relatively easy to obtain from the group of aluminum oxide, zirconium oxide, zinc oxide, tin oxide, yttrium oxide, cerium oxide, titanium oxide, copper oxide, and bismuth oxide. One or more selected metal oxide fine particles are preferable.

  The surface of the metal oxide fine particles may be treated with a silane coupling agent or a titanium coupling agent. By the surface treatment, the compatibility between the metal oxide fine particles and the binder precursor or the organic solvent is increased.

  The average particle diameter of the metal oxide fine particles is more preferably 5 to 80 nm, and further preferably 5 to 50 nm. When the average particle diameter of the metal oxide fine particles is within this range, fine irregularities are formed on the surface of the reflective layer, and the anchor effect described above can be obtained. The average particle diameter of the metal oxide fine particles is measured, for example, by a Coulter counter method.

The metal oxide fine particles may be porous, and the specific surface area is preferably 200 m ² / g or more. If the metal oxide fine particles are porous, impurities are easily adsorbed in the porous voids.

  The amount of the metal oxide fine particles contained in the reflective layer forming composition is 0.1 to 20% by mass with respect to the total mass of components other than the solvent (organic solvent and water) contained in the reflective layer forming composition. It is preferable that it is 1 to 10% by mass. If the amount of the metal oxide fine particles is too small, the above-described anchor effect is not sufficient. On the other hand, if the amount is too large, the amount of the binder precursor is relatively decreased, and the strength of the resulting reflective layer may be decreased.

  On the other hand, the inorganic particles may be particles other than the metal oxide fine particles (hereinafter also referred to as “other inorganic particles”). When other inorganic particles are contained in the reflective layer forming composition, the gap between the reflective materials is filled with the inorganic particles, and the viscosity of the reflective layer forming composition is increased.

  Examples of other inorganic particles include oxide particles such as silicon oxide, fluoride particles such as magnesium fluoride, and mixtures thereof. The other inorganic particles are preferably oxide particles, and particularly preferably silicon oxide. The surface of other inorganic particles may be treated with a silane coupling agent or a titanium coupling agent. By the surface treatment, compatibility between the other inorganic particles and the alkoxysilane compound or the organic solvent is increased.

  The content of other inorganic particles contained in the reflective layer forming composition is preferably 0.1 to 10% by mass, and 0.2 to 5% by mass with respect to the total mass of the reflective layer forming composition. It is more preferable that If the other inorganic particles exceeds 10% by mass, cracks are likely to occur during the formation of the reflective layer, and if it is less than 0.1%, the thickening effect of the composition for forming the reflective layer is reduced.

  The average particle size of the other inorganic particles is preferably 100 nm or more and 100 μm or less, and more preferably 100 nm or more and 50 μm or less, more preferably 1 μm or more and 30 μm or less from the viewpoint of filling a gap generated at the interface between the reflective materials. It is further preferable that The average particle diameter of other inorganic particles can be measured by, for example, a Coulter counter method.

2-1-5. Clay mineral particles The composition for reflection layer formation may contain clay mineral particles. When clay mineral particles are contained in the reflective layer forming composition, the viscosity of the reflective layer forming composition increases, and sedimentation of the reflective material is suppressed. Examples of clay mineral particles include layered silicate minerals, imogolite, allophane and the like. These particles have a very large surface area, and can increase the viscosity of the composition for forming a reflective layer in a small amount.

  Here, the layered silicate mineral preferably has a mica structure, a kaolinite structure, or a smectite structure. Layered silicate mineral particles tend to form a card house structure when the reflective layer-forming composition is allowed to stand. When the layered silicate mineral particles form a card house structure, the viscosity of the reflective layer forming composition is greatly increased. On the other hand, the card house structure tends to collapse when a certain pressure is applied, and thereby the viscosity of the composition for forming a reflective layer is lowered. That is, when layered silicate mineral particles are contained in the reflective layer forming composition, the viscosity of the reflective layer forming composition increases in a stationary state, and when a certain pressure is applied, the reflective layer forming composition The viscosity of the product is lowered.

  Examples of such layered silicate minerals include natural or synthetic hectorite, saponite, stevensite, hydelite, montmorillonite, nontrinite, bentonite, laponite and other smectite clay minerals and Na-type tetralithic fluoromica. Non-swelling mica such as swellable mica genus clay minerals such as Li-type tetralithic fluorine mica, Na-type fluorine teniolite, Li-type fluorine teniolite, muscovite, phlogopite, fluorine phlogopite, sericite, potassium tetrasilicon mica Genus clay minerals, vermiculite and kaolinite, or mixtures thereof.

  Examples of commercial products of clay mineral particles include Laponite XLG (synthetic hectorite analogue manufactured by LaPorte, UK), Laponite RD (Synthetic hectorite analogue produced by LaPorte, UK), Thermabis (Synthetic product, Henkel, Germany) Hectorite-like substance), smecton SA-1 (saponite-like substance manufactured by Kunimine Industry Co., Ltd.), Bengel (natural bentonite sold by Hojun Co., Ltd.), Kunivia F (natural montmorillonite sold by Kunimine Industry Co., Ltd.), bee gum ( Natural hectorite manufactured by Vanderbilt, USA, Daimonite (synthetic swellable mica manufactured by Topy Industries, Ltd.), Micromica (synthetic non-swellable mica manufactured by Coop Chemical Co., Ltd.), Somasif (Coop Chemical Co., Ltd.) ) Synthetic swelling mica), SWN (synthetic smectite manufactured by Corp Chemical Co.), SWF ( Synthetic smectite manufactured by Top Chemical Co., Ltd.), M-XF (white mica manufactured by Repco), S-XF (metal mica manufactured by Repco), PDM-800 (fluorine manufactured by Topy Industries, Ltd.) Phlogopite), sericite OC-100R (sericite manufactured by Oakem Tsusho Co., Ltd.), PDM-K (G) 325 (potassium tetrasilicon mica manufactured by Topy Industries, Ltd.), and the like.

  The content of the clay mineral particles is preferably 0.1 to 5% by mass, and more preferably 0.2 to 2% by mass with respect to the total mass of the reflective layer forming composition. When the content of the clay mineral particles is small, the viscosity of the reflective layer forming composition is difficult to increase, and the reflective material tends to settle. On the other hand, if the content of the clay mineral particles is excessive, the viscosity of the reflective layer forming composition becomes too high, and the reflective layer forming composition may not be uniformly discharged from the coating apparatus.

  The surface of the clay mineral particles may be modified (surface treatment) with an ammonium salt or the like in consideration of compatibility with the solvent in the reflective layer forming composition.

2-1-6. Silane Coupling Agent The reflective layer forming composition may further contain a silane coupling agent. When the silane coupling agent is contained in the reflective layer forming composition, the adhesion between the resulting reflective layer and the substrate is increased, and the durability of the light emitting device is improved.

  Examples of silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyl Methyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3 -Acryloxypropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-Ami Propyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltriethoxysilane, N- (vinylbenzyl) ) -2-Aminoethyl-3-aminopropyltrimethoxysilane hydrochloride, 3-ureidopropyltrimethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, Bis (triethoxysilylpropyl) tetrasulfide, 3-isocyanatopropyltriethoxysilane and the like are included. In the composition for forming a reflective layer, these may be contained alone or in combination of two or more.

  The amount of the silane coupling agent contained in the reflective layer forming composition is 0.5 to 10% by mass relative to the total mass of components other than the solvent (organic solvent and water) contained in the reflective layer forming composition. It is preferable that it is 1 to 7% by mass. If the amount of the silane coupling agent is too small, the adhesion between the resulting reflective layer and the substrate is not sufficiently increased, and if it is too large, the heat resistance may be lowered.

2-1-7. Method for preparing a composition for forming a reflective layer A method for preparing a composition for forming a reflective layer is a method in which raw materials such as a reflective material, a binder precursor, a solvent, inorganic particles, clay mineral particles, and a silane coupling agent are mixed together. It may be a method, or may be a method of mixing a plurality of raw materials in advance and mixing the mixed liquids later. In order to enhance the thickening effect of inorganic particles and clay mineral particles, it is preferable to disperse one or both of inorganic particles and clay mineral particles in a solvent and then mix with the remaining components.

  Moreover, in order to improve the uniformity in the composition for forming a reflective layer, it is preferable to disperse all or part of the raw material of the composition for forming a reflective layer with the following apparatus. When the reflective material is dispersed with the following apparatus, aggregation of the reflective material is reduced, and a denser and highly reflective coating film is obtained.

-Mixing / dispersing device Examples of devices for dispersing all or part of the raw material of the composition for forming the reflective layer include a magnetic stirrer, ultrasonic dispersing device, homogenizer, stirring mill, blade kneading stirring device, thin film swirl type A disperser, a high-pressure impact disperser, a rotating / revolving mixer, and the like are included.

  More specifically, Ultra Turrax (manufactured by IKA Japan), TK homomixer (manufactured by Primix), TK pipeline homomixer (manufactured by Primix), TK Philmix (manufactured by Primix), Claremix (M Technique) ), Claire SS5 (manufactured by M Technique), Cavitron (manufactured by Eurotech), medialess stirrers such as Fine Flow Mill (manufactured by Taiheiyo Kiko), Viscomill (manufactured by IMEX), Apex Mill (manufactured by Kotobuki Industries) Co., Ltd.), Star Mill (Ashizawa, Finetech Co., Ltd.), DMPA / S Super Flow (Nihon Eirich Co., Ltd.), MP Mill (Inoue Seisakusho Co., Ltd.), Spike Mill (Inoue Seisakusho Co., Ltd.), Mighty Mill (Inoue Seisakusho Co., Ltd.) ), SC mill (Mitsui Mining Co., Ltd.) etc. Imaiza (Sugino Machine Ltd.), Nanomizer (manufactured by Yoshida Kikai), and a high-pressure impact type dispersing device such as NANO 3000 (manufactured by Bitsubusha). In addition, a rotating / revolving mixer such as Awatori Nerita (manufactured by Shinky Corporation) and an ultrasonic dispersion device are also preferably used.

-Physical properties of the composition for forming a reflective layer The viscosity of the composition for forming a reflective layer measured at 25 ° C with a vibration viscometer is preferably 5 to 1,000,000 cP, more preferably 10 to 100. 1,000 cP, more preferably 30 to 10,000 cP. When the viscosity of the composition for forming a reflective layer is within the above range, a reflective layer having the above-described shape is easily obtained.

  Moreover, it is preferable that the solid content concentration of the composition for reflective layer formation is 55-95 mass%, More preferably, it is 60-80 mass%, More preferably, it is 60-75 mass%. The lower the solid content concentration of the composition for forming the reflective layer, the more the angle formed between the tangent of the portion having a film thickness half that of the thick film uniform region and the substrate in the film thickness gradient region of the resulting reflective layer It tends to be small. The viscosity of the reflective layer forming composition is appropriately selected according to a desired angle.

2-2. Step of applying the composition for forming a reflective layer The above-described composition part for forming a reflective layer is applied onto a substrate. At this time, when the light emitting element is already arranged on the substrate, the reflective layer forming composition is applied with a predetermined gap from the side surface of the light emitting element. On the other hand, when the light emitting element is not arranged on the substrate, the reflective layer forming composition is applied around the place where the light emitting element is arranged. At this time, the reflective layer forming composition is applied so that a predetermined gap is formed between the side surface of the light emitting element and the reflective layer. Thereafter, the reflective layer forming composition is cured.

  In addition, as described above, as a method of forming the film thickness gradient region and the film thickness uniform region in the obtained reflective layer, for example, when applying the reflective layer forming composition, the light emitting element is formed from the outer peripheral side of the light emitting device. The reflective layer forming composition is applied toward the region where the light emitting element is disposed, or the reflective layer forming composition is applied from the region side where the light emitting element is disposed toward the outer peripheral side of the light emitting device. For example, reducing the amount of the reflective layer forming composition to be applied. In particular, it is preferable to apply the reflective layer forming composition from the region side where the light emitting element is disposed toward the outer peripheral side of the light emitting device. When the reflective layer forming composition is applied by such a method, the film thickness gradient in the film thickness gradient region tends to be gradual. The following method is mentioned as an example of the method of apply | coating the composition for reflective layer formation toward the outer peripheral side of a light-emitting device from the area | region side which arrange | positions a light emitting element. First, the reflective layer forming composition is applied so as to surround a region where the light emitting element is to be disposed and with a predetermined gap from the region where the light emitting element is to be disposed. Subsequently, the reflective layer forming composition is further applied around the area where the reflective layer forming composition is applied. The said operation | work is repeated and the composition for reflective layer formation is apply | coated to the outer peripheral side of a light-emitting device. At this time, the coating amount of the reflective layer forming composition may be constant in all regions, but the coating amount is changed according to the region where the reflective layer forming composition is applied, and the thickness of the resulting reflective layer is changed. You may adjust. Moreover, you may adjust the space | interval of the area | regions which apply | coat the composition for reflective layer formation, and may adjust the thickness of the reflective layer obtained.

  Examples of the method for applying the reflective layer forming composition include application by a dispenser such as a jet dispenser, application by an inkjet method, screen printing, and the like. Moreover, the method of coating | covering the area | region which does not form a reflection layer with another member, and apply | coating the composition for reflection layer formation only to a specific area | region with a well-known coating method etc. may be used.

  As described above, after the reflective layer forming composition is applied to a desired region and film thickness, the reflective layer forming composition is cured. The curing method of the reflective layer forming composition is appropriately selected according to the type of the binder precursor in the reflective layer forming composition. For example, when the binder precursor is a silicone resin, an epoxy resin, or a precursor thereof, it may be a method of heating to 20 to 150 ° C., for example.

  On the other hand, when the binder precursor in the composition for forming a reflective layer is an alkoxysilane compound, it is preferably heated to 20 to 200 ° C, more preferably 100 to 150 ° C. By setting the heating temperature to 20 ° C. or higher, the solvent in the coating film can be sufficiently volatilized. Further, by setting the heating temperature to 100 ° C. or higher, water generated during the polycondensation of the alkoxysilane compound is sufficiently volatilized and a dense reflective layer is easily obtained.

2-3. Arrangement Step of Light-Emitting Element As described above, the arrangement of the light-emitting element may be performed before the application step of the composition for forming a reflective layer, or may be performed after the application step.

  When the light emitting element is an LED element, the LED element may be fixed to the substrate, and the electrode of the substrate may be connected to the cathode electrode and the anode electrode of the LED element. The method for connecting the LED element and the electrode and the method for fixing the LED element to the substrate are not particularly limited, and may be the same as a conventionally known method.

2-4. Step of forming wavelength conversion layer The step of forming wavelength conversion layer may be a step of applying and curing a composition for wavelength conversion layer containing phosphor particles so as to cover the light emitting element. The composition for wavelength conversion layer contains phosphor particles and a binder component.

  The binder component can be a transparent resin or a precursor thereof, or a polysiloxane precursor (alkoxysilane compound) included in the wavelength conversion layer. Moreover, a solvent is contained in the composition for wavelength conversion layers as needed. When the binder component is the aforementioned transparent resin or a precursor thereof, the solvent is a hydrocarbon such as toluene or xylene; a ketone such as acetone or methyl ethyl ketone; an ether such as diethyl ether or tetrahydrofuran; propylene glycol monomethyl ether acetate, ethyl It may be an ester such as acetate. On the other hand, when the binder component is an alkoxysilane compound, the solvent may be the same as the organic solvent contained in the above-described reflective layer forming composition.

  Moreover, mixing of the composition for wavelength conversion layers can be performed with a stirring mill, a blade kneading stirring apparatus, a thin-film swirl type disperser, or the like. By adjusting the stirring conditions, the precipitation of the phosphor particles in the wavelength conversion layer composition is suppressed.

  The method for applying the composition for wavelength conversion layer is appropriately selected depending on the type of the binder, and can be, for example, dispenser application or spray application. Moreover, this is hardened after application | coating of the composition for wavelength conversion layers. The curing method and curing conditions of the wavelength conversion layer composition are appropriately selected depending on the type of resin. An example of the curing method is heat curing.

2-5. Step of forming light transmissive layer In the method for manufacturing a light emitting device of the present invention, a step of forming a light transmissive layer may be performed so as to cover the wavelength conversion layer or the like. The step of forming the light transmissive layer may be a step of applying and curing the composition for light transmissive layer. The material contained in the composition for forming a light transmissive layer may be the aforementioned light transmissive material or a precursor thereof. The composition for light transmissive layer may contain a solvent. The solvent contained in the composition for light transmissive layer is not particularly limited as long as it can dissolve or disperse the light transmissive material or its precursor. When the light-transmitting material or its precursor is the above-mentioned transparent resin or its precursor, the solvent is hydrocarbons such as toluene and xylene; ketones such as acetone and methyl ethyl ketone; ethers such as diethyl ether and tetrahydrofuran; propylene It may be an ester such as glycol monomethyl ether acetate or ethyl acetate. On the other hand, when the translucent material precursor is an alkoxysilane compound, the solvent may be the same as the solvent contained in the reflective layer forming composition.

  The method for applying the light transmissive layer composition is not particularly limited, and may be appropriately selected depending on the light transmissive material contained in the light transmissive layer composition, and may be dispenser coating, spray coating, or the like. Although this is hardened after application | coating of the composition for translucent layers, the hardening method and hardening conditions are suitably selected with the kind of binder component. An example of the curing method is heat curing.

  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.

[Example 1]
-Preparation of a composition for forming a reflective layer 25% by mass of dimethyldimethoxysilane, 60% by mass of methanol, 14.99% by mass of water, and 0.01% by mass of nitric acid were mixed and stirred at 23 ° C for 3 hours. The mixture was reacted at 3 ° C. with stirring for 3 days to prepare a solution containing a polysiloxane oligomer. Subsequently, 6 g of titanium oxide (Fuji Titanium Industry TA-100 particle size 600 nm) and 1 g of 1,3-butanediol were mixed with 3 g of the polysiloxane oligomer solution to obtain a composition for forming a reflective layer. The viscosity of the reflective layer forming composition measured at 25 ° C. with a vibration viscometer was 800 cP.

-Arrangement of LED element A substrate having a cavity was prepared. The substrate was made of a polyphthalamide (PPA) resin. The substrate is a rectangular parallelepiped of 5 mm × 5 mm × 1.8 mm, in which a quadrangular frustum-shaped cavity having an opening of 4.8 × 4.8 mm, a wall surface angle of 70 °, and a depth of 0.85 mm is formed. A metal wiring and an LED element arranged on the substrate were connected by a protruding electrode to obtain a package. The outer shape of the LED element was 305 μm × 330 μm × 100 μm. The peak wavelength of the emitted light from the LED element was 475 nm.

-Formation of a reflective layer The composition for reflective layer formation was apply | coated to the outer peripheral side of the board | substrate in the rectangular shape so that a LED element might be enclosed with a dispenser with a nozzle diameter of 150 micrometers. Next, the reflective layer forming composition was applied in a rectangular shape to the inside of the region where the reflective layer forming composition was applied. The reflective layer forming composition was similarly applied until the distance between the LED element side end of the reflective layer and the outer periphery of the LED element was 400 μm. That is, in this example, the reflective layer forming composition was applied so as to go from the outer peripheral side of the substrate toward the LED element. Then, it baked at 150 degreeC for 1 hour, and formed the reflection layer. The obtained reflective layer included a film thickness gradient region and a film thickness uniform region. The film thickness in the uniform film thickness region was 60 μm. In addition, the angle formed by the substrate and the tangent of a portion having a film thickness that is half the film thickness of the film thickness region in the film thickness gradient region was 50 °.

-Formation of wavelength conversion layer Silicone resin (manufactured by Shin-Etsu Silicone, KER2600) and yellow phosphor (manufactured by Nemoto Special Chemical Co., Ltd., YAG 450C205 (volume average particle diameter D50 20.5 μm)) are mixed, and the wavelength conversion layer A composition was obtained. The density | concentration of the yellow fluorescent substance in the composition for wavelength conversion layers was 5 mass%. And the composition for wavelength conversion layers was potted with the dispenser to the above-mentioned package. And after heating the composition for wavelength conversion layers at 100 degreeC for 1 hour, it heated at 150 degreeC for 1 hour, and obtained the wavelength conversion layer.

[Example 2]
An LED device was obtained in the same manner as in Example 1 except that the distance between the LED element side end of the reflective layer and the outer periphery of the LED element was changed. The distance between the LED element side end of the reflective layer and the outer periphery of the LED element was 200 μm. The film thickness in the uniform film thickness region was 60 μm. In addition, the angle formed by the substrate and the tangent of a portion having a film thickness that is half the film thickness of the film thickness region in the film thickness gradient region was 50 °.

[Example 3]
2 g of silicone resin KER2600, 0.5 g of ethyl acetate, 0.8 g of titanium oxide TA-100, and 1 g of 1,3-butanediol were mixed to prepare a composition for forming a reflective layer. The viscosity of the reflective layer forming composition measured at 25 ° C. with a vibration viscometer was 550000 cP. And it apply | coated so that the distance of a LED element and a reflection layer might be set to 200 micrometers by the method similar to Example 1, and it heated at 150 degreeC for 1 h, and obtained the reflection layer. The film thickness in the uniform film thickness region was 70 μm. In addition, the angle formed by the substrate and the tangent of a portion having a film thickness half the film thickness of the film thickness area in the film thickness gradient area was 60 °.

[Example 4]
The composition for forming a reflective layer was changed to the following composition. Moreover, the reflective layer forming composition was applied in a rectangular shape so as to surround the LED element, and then the reflective layer forming composition was further applied in a rectangular shape outside the application region. This was repeated up to the outer peripheral side of the substrate. That is, the reflective layer forming composition was applied from the LED element side toward the outer peripheral side of the substrate. Then, it baked at 150 degreeC for 1 hour, and formed the reflection layer. The distance between the LED element side end of the reflective layer and the outer periphery of the LED element was 200 μm. The film thickness in the uniform film thickness region was 60 μm. In addition, the angle formed by the substrate and the tangent of the portion having a film thickness that is half the film thickness of the film thickness region in the film thickness gradient region was 40 °.

-Preparation of composition for forming reflective layer 15.5 parts by mass of tetramethoxysilane (75.0 mol% with respect to the entire silane compound), 9.5 parts by mass of methyltrimethoxysilane (25.0 with respect to the entire silane compound) Mol%), 60 parts by mass of methanol, 14.99 parts by mass of water, and 0.01 parts by mass of nitric acid, and the mixture was stirred at 23 ° C. for 3 hours and then reacted at 26 ° C. with stirring for 3 days to obtain polysiloxane. A solution containing the oligomer was prepared. Subsequently, 6 g of titanium oxide (Fuji Titanium Industry TA-100 particle size 600 nm) and 1 g of ethylene glycol were mixed with 3 g of the polysiloxane oligomer solution to obtain a composition for forming a reflective layer. The viscosity of the reflective layer forming composition measured at 25 ° C. with a vibration viscometer was 650 cP.

[Example 5]
An LED device was obtained in the same manner as in Example 4 except that the distance between the LED element side end of the reflective layer and the outer periphery of the LED element was changed. The distance between the LED element side end of the reflective layer and the outer periphery of the LED element was 100 μm. The film thickness in the uniform film thickness region was 60 μm. In addition, the angle formed by the substrate and the tangent of the portion having a film thickness that is half the film thickness of the film thickness region in the film thickness gradient region was 40 °.

[Example 6]
An LED device was obtained in the same manner as in Example 4 except that the distance between the LED element side end of the reflective layer and the outer periphery of the LED element was changed. The distance of the reflective layer from the outer periphery of the LED element was 30 μm. The film thickness in the uniform film thickness region was 60 μm. In addition, the angle formed by the substrate and the tangent of the portion having a film thickness that is half the film thickness of the film thickness region in the film thickness gradient region was 40 °.

[Example 7]
An LED device was obtained in the same manner as in Example 1 except that the composition for forming a reflective layer was prepared as follows. The distance between the LED element side end of the reflective layer and the outer periphery of the LED element was 100 μm. The film thickness in the uniform film thickness region was 60 μm. In addition, the angle formed by the substrate and the tangent of the portion having a film thickness that is half the film thickness of the film thickness region in the film thickness gradient region was 40 °.

-Preparation of composition for forming reflective layer 25 parts by mass of methyltrimethoxysilane, 60 parts by mass of methanol, 14.99 parts by mass of water, and 0.01 parts by mass of nitric acid were mixed and stirred at 23 ° C for 3 hours. The mixture was reacted at 26 ° C. with stirring for 3 days to prepare a solution containing a polysiloxane oligomer. Subsequently, 6 g of titanium oxide (Fuji Titanium Industry TA-100 particle size 600 nm) and 1 g of 1,3-butanediol were mixed with 3 g of the polysiloxane oligomer solution to obtain a composition for forming a reflective layer. The viscosity of the composition for forming a reflective layer measured at 25 ° C. with a vibration viscometer was 500 cP.

[Example 8]
A reflective layer forming composition prepared in the same manner as in Example 7 was used, and an LED device was obtained in the same manner as in Example 4. The distance between the LED element side end of the reflective layer and the outer periphery of the LED element was 100 μm. The film thickness in the uniform film thickness region was 60 μm. In addition, the angle formed by the substrate and the tangent of the portion having a film thickness that is half the film thickness of the film thickness region in the film thickness gradient region was 30 °.

[Example 9]
An LED device was obtained in the same manner as in Example 8 except that the distance between the LED element side end of the reflective layer and the outer periphery of the LED element was changed. The distance of the reflective layer from the outer periphery of the LED element was 30 μm. The film thickness in the uniform film thickness region was 60 μm. In addition, the angle formed by the substrate and the tangent of the portion having a film thickness that is half the film thickness of the film thickness region in the film thickness gradient region was 30 °.

[Example 10]
An LED device was obtained in the same manner as in Example 8, except that the nozzle diameter of the dispenser was changed to 250 μm and the reflective layer forming composition was applied once in a rectangular shape around the LED element. The distance of the reflective layer from the outer periphery of the LED element was 30 μm. The film thickness in the uniform film thickness region was 100 μm. In addition, the angle formed by the substrate and the tangent of the portion having a film thickness that is half the film thickness of the film thickness region in the film thickness gradient region was 40 °.

[Example 11]
An LED device was obtained in the same manner as in Example 8 except that the composition for forming a reflective layer was prepared as follows. The distance between the LED element side end of the reflective layer and the outer periphery of the LED element was 100 μm. The film thickness in the uniform film thickness region was 60 μm. In addition, the angle formed by the substrate and the tangent of the portion having a film thickness half the film thickness of the film thickness area in the film thickness gradient area was 20 °.

-Preparation of composition for forming reflective layer 25 parts by mass of methyltrimethoxysilane, 60 parts by mass of methanol, 14.99 parts by mass of water, and 0.01 parts by mass of nitric acid were mixed and stirred at 23 ° C for 3 hours. The mixture was reacted at 26 ° C. with stirring for 3 days to prepare a solution containing a polysiloxane oligomer. Subsequently, 6 g of titanium oxide (Fuji Titanium Industry TA-100 particle size 600 nm) and 1.3 g of 1,3-butanediol were mixed with 3 g of the polysiloxane oligomer solution to obtain a composition for forming a reflective layer. The viscosity of the reflective layer forming composition measured at 25 ° C. with a vibration viscometer was 450 cP.

[Example 12]
An LED device was obtained in the same manner as in Example 8 except that the composition for forming a reflective layer was prepared as follows. The distance between the LED element side end of the reflective layer and the outer periphery of the LED element was 100 μm. The film thickness in the uniform film thickness region was 60 μm. In addition, the angle formed by the substrate and the tangent of a portion having a film thickness that is half the film thickness of the film thickness area in the film thickness gradient area was 15 °.

-Preparation of composition for forming reflective layer 25 parts by mass of methyltrimethoxysilane, 60 parts by mass of methanol, 14.99 parts by mass of water, and 0.01 parts by mass of nitric acid were mixed and stirred at 23 ° C for 3 hours. The mixture was reacted at 26 ° C. with stirring for 3 days to prepare a solution containing a polysiloxane oligomer. Subsequently, 6 g of titanium oxide (Fuji Titanium Industry TA-100 particle size 600 nm) and 1.5 g of 1,3-butanediol were mixed with 3 g of the polysiloxane oligomer solution to obtain a composition for forming a reflective layer. The viscosity of the reflective layer forming composition measured at 25 ° C. with a vibration viscometer was 350 cP.

[Example 13]
An LED device was obtained in the same manner as in Example 1 except that the composition for forming a reflective layer was prepared as follows. The distance between the LED element side end of the reflective layer and the outer periphery of the LED element was 100 μm. The film thickness in the uniform film thickness region was 60 μm. In addition, the angle formed by the substrate and the tangent of the portion having a film thickness that is half the film thickness of the film thickness region in the film thickness gradient region was 70 °.

-Preparation of composition for forming reflective layer 25 parts by mass of methyltrimethoxysilane, 60 parts by mass of methanol, 14.99 parts by mass of water, and 0.01 parts by mass of nitric acid were mixed and stirred at 23 ° C for 3 hours. The mixture was reacted at 26 ° C. with stirring for 3 days to prepare a solution containing a polysiloxane oligomer. Subsequently, 6 g of titanium oxide (Fuji Titanium Industry TA-100, particle size 600 nm), 0.4 g of ethanol, and 0.3 g of acetone were mixed with 3 g of the polysiloxane oligomer solution to obtain a composition for forming a reflective layer. The viscosity of the reflective layer forming composition measured at 25 ° C. with a vibration viscometer was 150 cP.

[Example 14]
A reflective layer forming composition prepared in the same manner as in Example 7 was used, and an LED device was obtained in the same manner as in Example 4. The distance between the LED element side end of the reflective layer and the outer periphery of the LED element was 15 μm. The film thickness in the uniform film thickness region was 60 μm. In addition, the angle formed by the substrate and the tangent of the portion having a film thickness that is half the film thickness of the film thickness region in the film thickness gradient region was 30 °.

[Example 15]
A reflective layer forming composition prepared in the same manner as in Example 7 was used, and an LED device was obtained in the same manner as in Example 4. The distance between the LED element side end of the reflective layer and the outer periphery of the LED element was 15 μm. The film thickness in the uniform film thickness region was 60 μm. In addition, the angle formed by the substrate and the tangent of the portion having a film thickness that is half the film thickness of the film thickness region in the film thickness gradient region was 30 °.

[Example 16]
An LED device was obtained in the same manner as in Example 1 except that the composition for forming a reflective layer was prepared as follows. The distance between the LED element side end of the reflective layer and the outer periphery of the LED element was 100 μm. The film thickness in the uniform film thickness region was 60 μm. In addition, the angle formed by the substrate and the tangent of the portion having a film thickness that is half the film thickness of the film thickness region in the film thickness gradient region was 40 °.

-Preparation of composition for forming reflective layer 25 parts by mass of methyltrimethoxysilane, 60 parts by mass of methanol, 14.99 parts by mass of water, and 0.01 parts by mass of nitric acid were mixed and stirred at 23 ° C for 3 hours. The mixture was reacted at 26 ° C. with stirring for 3 days to prepare a solution containing a polysiloxane oligomer. Subsequently, 3 g of the polysiloxane oligomer solution was added with 6 g of titanium oxide (Fuji Titanium Industry TA-100, particle size 600 nm), 0.1 g of MK-100: synthetic mica (Micromica MK-100, manufactured by Corp Chemical), and 470: silica. (Silysia 470, manufactured by Fuji Silysia Chemical) 0.2 g of an average particle size of 14 μm and 1 g of 1,3-butanediol were mixed to obtain a composition for forming a reflective layer. The viscosity of the reflective layer forming composition measured at 25 ° C. with a vibration viscometer was 550 cP.

[Example 17]
The composition for forming a reflective layer described in Example 7 was applied around the area of the substrate on which the LED element was mounted in the same manner as in Example 1 and cured by heating. Then, the LED element was mounted in a predetermined position to obtain an LED device. The distance between the LED element side end of the reflective layer and the outer periphery of the LED element was 100 μm, and the film thickness in the uniform film thickness region was 60 μm. In addition, the angle formed by the substrate and the tangent of the portion having a film thickness that is half the film thickness of the film thickness region in the film thickness gradient region was 40 °.

[Comparative Example 1]
Using a dispenser having a nozzle diameter of 50 μm, the reflective layer forming composition was applied in a rectangular shape on the outer peripheral side of the substrate so as to surround the LED element. Next, an LED device was obtained in the same manner as in Example 1 except that the reflective layer forming composition was further applied twice in a rectangular shape to the inside. The distance between the LED element side end of the reflective layer and the outer periphery of the LED element was 400 μm. The film thickness in the uniform film thickness region was 60 μm. In addition, the angle formed by the substrate and the tangent of the portion having a film thickness that is half the film thickness of the film thickness region in the film thickness gradient region was 85 °.

[Comparative Example 2]
An LED device was obtained in the same manner as in Example 4 except that the same reflective layer forming composition as in Example 1 was used, and the reflective layer forming composition was applied using a dispenser having a nozzle diameter of 50 μm. The distance between the LED element side end of the reflective layer and the outer periphery of the LED element was 400 μm. The film thickness in the uniform film thickness region was 15 μm. In addition, the angle formed by the substrate and the tangent of the portion having a film thickness half the film thickness of the film thickness area in the film thickness gradient area was 10 °.

[Comparative Example 3]
An LED device was obtained in the same manner as in Example 1 except that the distance between the LED element side end of the reflective layer and the outer periphery of the LED element was changed. The distance between the LED element side end of the reflective layer and the outer periphery of the LED element was 700 μm. The film thickness in the uniform film thickness region was 60 μm. In addition, the angle formed by the substrate and the tangent of a portion having a film thickness that is half the film thickness of the film thickness region in the film thickness gradient region was 50 °.

[Comparative Example 4]
An LED device was obtained in the same manner as in Example 1 except that the distance between the LED element side end of the reflective layer and the outer periphery of the LED element was changed. The reflective layer was formed such that the distance between the LED element side end of the reflective layer and the outer periphery of the LED element was 0 μm, that is, the reflective layer and the LED element were in contact. The film thickness in the uniform film thickness region was 60 μm.

[Comparative Example 5]
An LED device was obtained in the same manner as in Example 1 except that the composition for forming a reflective layer was prepared as follows. The distance between the LED element side end of the reflective layer and the outer periphery of the LED element was 100 μm. The film thickness in the uniform film thickness region was 60 μm. In addition, the angle formed by the substrate and the tangent of the portion having a film thickness that is half the film thickness of the film thickness region in the film thickness gradient region was 85 °.

-Preparation of composition for forming reflective layer 25 parts by mass of methyltrimethoxysilane, 60 parts by mass of methanol, 14.99 parts by mass of water, and 0.01 parts by mass of nitric acid were mixed and stirred at 23 ° C for 3 hours. The mixture was reacted at 26 ° C. with stirring for 3 days to prepare a solution containing a polysiloxane oligomer. Subsequently, 6 g of titanium oxide (Fuji Titanium Industry TA-100 particle size 600 nm) and 0.6 g of acetone were mixed with 2 g of the polysiloxane oligomer solution to obtain a composition for forming a reflective layer. The viscosity of the reflective layer forming composition measured at 25 ° C. with a vibration viscometer was 450 cP.

[Evaluation]
The reflectivity of the composition for forming a reflective layer prepared in Examples and Comparative Examples and the total luminous flux of the LED device were evaluated by the following methods, respectively. The results are shown in Table 1.

<Reflectance>
The reflective layer forming composition of Example 1 and Example 3 was applied to a transparent 1 mm thick glass plate and heated at 150 ° C. for 1 hour to be cured. At this time, the thickness of the reflective layer was 60 μm. About the said sample, the reflectance was measured with the spectrophotometer V-670 (made by JASCO Corporation).

<Total luminous flux>
The total luminous flux was measured for each LED device using a spectral radiance meter CS-2000 manufactured by Konica Minolta and an integrating sphere. The total luminous flux value of the LED device of Comparative Example 1 was set to 100%, and the converted value based on the total luminous flux value was defined as the total luminous flux of each LED device.

<Angle>
In the thickness gradient region, the angle formed by the substrate and the tangent of the portion having a film thickness that is half the thickness of the thick film uniform region is the same as in each example and comparative example, and a sample in which a reflective layer is formed is prepared. Measured from a micrograph of the cross-sectional shape of the sample.

  As shown in Table 1, the distance between the LED element side end of the reflective layer and the outer periphery of the LED element is 5 to 500 μm, and the angle of the thickness gradient region of the reflective layer is 15 to 80 ° In Examples 1 to 17, the total luminous flux was increased as compared with Comparative Example 1. If the shape of the reflective layer is the above shape, it is assumed that the light from the LED element was easily reflected on the light extraction surface side of the LED device.

  On the other hand, when the reflective layer was in contact with the side surface of the LED element (Comparative Example 4), the total luminous flux was low. It is surmised that the reason is that light could not be sufficiently extracted from the side surface of the LED element. Moreover, also when the distance of the LED element side edge part of a reflection layer and the outer periphery of an LED element was too large (comparative example 3), the total light beam became low. Furthermore, even if the distance between the LED element side end of the reflective layer and the outer periphery of the LED element is 5 to 500 μm, if the angle is too large or too small (Comparative Examples 1, 2, and 5), The light emitted from the side surface of the LED element could not be reflected to the light extraction surface side, and it was difficult to increase the total luminous flux.

  The light emitting device of the present invention has high light extraction efficiency. Therefore, it is very useful as various optical devices.

DESCRIPTION OF SYMBOLS 1 Substrate 2 Light emitting element 3 Reflective layer 4 Wavelength conversion layer 5 Translucent layer 11 Metal wiring 12 Projection electrode 100 Light emitting device a Film thickness inclination area b Film thickness uniform area

Claims (16)

A light-emitting device comprising: a substrate; a light-emitting element disposed on the substrate; and a reflective layer including a binder and a reflective material disposed around the light-emitting element and spaced apart from the outer periphery of the light-emitting element.
The distance between the light emitting element side end of the reflective layer and the outer periphery of the light emitting element is 5 to 500 μm,
The reflective layer is located on the outer peripheral side of the light emitting device from the thickness inclined region, the film thickness inclined region where the film thickness increases from the light emitting element side end toward the outer peripheral side of the light emitting device, Including a uniform film thickness uniform region,
The light emitting device, wherein an angle formed by a tangent of the reflective layer at a portion having a film thickness half the film thickness of the film thickness uniform area in the film thickness gradient area and the substrate is 15 to 80 °.   The light emitting device according to claim 1, wherein a distance between the light emitting element side end of the reflective layer and an outer periphery of the light emitting element is 10 to 300 μm.   The light emitting device according to claim 1 or 2, wherein the film thickness uniform region of the reflective layer has a thickness of 5 to 200 µm.   The light emitting device according to claim 1, wherein the reflective material is a white pigment.   The light-emitting device according to claim 1, wherein the binder is polysiloxane.   The light emission according to claim 5, wherein the polysiloxane includes a structure derived from at least one alkoxysilane compound selected from the group consisting of a bifunctional alkoxysilane compound, a trifunctional alkoxysilane compound, and a tetrafunctional alkoxysilane compound. apparatus.   The light emitting device according to any one of claims 1 to 6, wherein the reflective layer includes at least one of inorganic particles and clay mineral particles.   The light emitting device according to claim 1, wherein the light emitting element is an LED element that emits light from a side surface. A method for manufacturing a light emitting device according to claim 1,
A step of preparing a composition for forming a reflective layer, comprising a binder precursor and the reflective material;
Applying the reflective layer forming composition around a region where the light emitting element is disposed;
Disposing the light emitting element on the substrate;
A method for manufacturing a light emitting device, comprising:   The application process of the said composition for reflective layer formation is a process of apply | coating the said composition for reflective layer formation toward the outer peripheral side of the said light-emitting device from the area | region side which arrange | positions the said light emitting element. Method for manufacturing the light emitting device.   The manufacturing method of the light-emitting device of Claim 9 or 10 which performs the process of arrange | positioning the said light emitting element before the application | coating process of the said composition for reflective layer formation.   The manufacturing method of the light-emitting device of Claim 9 or 10 which performs the process of arrange | positioning the said light emitting element after the application | coating process of the said composition for reflective layer formation.   The manufacturing method of the light-emitting device as described in any one of Claims 9-12 whose viscosity measured at 25 degreeC with the vibration-type viscometer of the said composition for reflective layer formation is 5 to 1000000 cP.   The method for manufacturing a light emitting device according to any one of claims 9 to 13, wherein the binder precursor is an alkoxysilane compound.   The manufacturing method of the light-emitting device as described in any one of Claims 9-14 with which the said composition for reflective layer formation contains the organic solvent.   The method for manufacturing a light emitting device according to claim 9, wherein the composition for forming a reflective layer contains at least one of a monohydric alcohol and a polyhydric alcohol.

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