JP2006313886A - Light emitting device with silicone resin layer formed by screen printing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device wherein a light emitting element is coated with a silicone resin layer excellent in the thermal resistance, light stability against the short wavelength such as ultraviolet rays, and mechanical strength. <P>SOLUTION: The light emitting device incorporates a light emitting element and a silicone resin layer formed by a screen printing for coating this light emitting element. This silicone resin layer comprises the hardened materials composed of the hardened silicone resin composition containing (A) organopolysiloxane with the weight average molecular weight of not less than 5×10<SP>3</SP>in terms of the polystyrene, which is expressed by the average composition formula (1): R<SP>1</SP><SB>a</SB>(OX)<SB>b</SB>SiO<SB>(4-a-b)/2</SB>(wherein, R<SP>1</SP>is alkyl, alkenyl or aryl with the number of carbon atoms of 1 to 6, X is hydrogen atom, alkyl, alkenyl, alkoxy alkyl or acyl with the number of carbon atoms of 1 to 6, (a) is a value ranging from 1.05 to 1.5, (b) is a value satisfying the condition of 0<b<2, and (a+b) is a value satisfying the condition of 1.05<a+b<2), (B) condensation catalyst, (C) solvent, and (D) impalpable powder inorgaic filler. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light-emitting device that can be used for a liquid crystal backlight, an illumination light source, various indicators, a display, a traffic signal lamp, and the like, and more particularly to a light-emitting device in which a light-emitting element is covered with a silicone resin.

  In a light-emitting device using a light-emitting element such as an LED, the light-emitting element is covered with a transparent resin layer that functions as a phosphor-containing layer, a lens, and the like. As a material for such a coating layer, an epoxy resin has been conventionally used, and recently a silicone resin has attracted attention because of its high heat resistance.

However, short-wavelength LEDs such as blue LEDs and ultraviolet LEDs have been developed, and the resin layer requires a tougher material that not only withstands the heat generation of the element but also withstands such high-energy short-wavelength light. It has been. Since conventionally proposed silicone resins are of the addition-curing type utilizing hydrosilylation reaction, the proportion of silylene bond in the cured product is large. Since the silicon bond is easily cleaved by light or heat, the main skeleton in the cured product is deteriorated and oily silicone having low molecular weight and fluidity tends to bleed out. As a result, the mechanical strength of the cured product tends to decrease and become brittle, and heat deformation tends to occur. In addition, the bleed-out low molecular weight silicone component may cause various obstacles. Furthermore, in such a state, color unevenness and color tone change are likely to occur during light emission, and the color tone characteristics of the light emitting element may be affected.
Conventionally, a method of dropping a resin on a light emitting element has been used to apply a sealing resin to the light emitting element. However, since the film thickness of the resin layer formed by this method is low in uniformity, it causes color unevenness during light emission. In order to solve the drawbacks of the dropping method, a screen printing method has been used. In the screen printing method, it is required that the resin to be used is easily peeled off from the metal mask during printing, and that the adhesiveness with the light emitting element is high after curing, but a resin material that sufficiently satisfies these is not known.

  Accordingly, an object of the present invention is to provide a light emitting device in which a light emitting element is coated with a silicone resin layer that is excellent in heat resistance, light resistance to high energy light such as ultraviolet rays, and mechanical strength, and that is suitable for formation by a screen printing method. Is to provide.

As a means for solving the above problems, the present invention provides:
A light-emitting element and a resin layer screen-printed to cover the light-emitting element;
The resin layer is
(I) The following average composition formula (1):
R ¹ _a (OX) _b SiO _{(4-ab) / 2} (1)
Wherein R ¹ is independently an alkyl group having 1 to 6 carbon atoms, an alkenyl group or an aryl group, and X is independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an alkenyl group. An alkoxyalkyl group or an acyl group, a is a number from 1.05 to 1.5, b is a number satisfying 0 <b <2, where a + b is a number satisfying 1.05 <a + b <2.)
An organopolysiloxane having a polystyrene-equivalent weight average molecular weight of 5 × 10 ³ or more,
(B) a condensation catalyst,
Provided is a light emitting device comprising a cured product of a curable silicone resin composition comprising (c) a solvent and (d) a fine powder inorganic filler.
The present invention also provides a method for producing a light-emitting device, which comprises applying the curable silicone resin composition described above on a light-emitting element by screen printing, curing the obtained composition layer, and coating the cured resin layer with the cured resin layer. Also provide.

  The silicone resin composition used for coating the light-emitting element in the light-emitting device of the present invention has no heat and light resistance because it has no silylene bond in the cured product, and has high mechanical strength and optical transparency. Excellent birefringence is small.

  In addition, since the resin layer is formed by screen printing, the film thickness is highly uniform, and color unevenness hardly occurs when the light emitting element emits light. Furthermore, the resin composition used has an advantage that it is easily peeled off from a mask such as a metal mask in screen printing, but has high adhesion to the light emitting element and high durability after curing.

  Therefore, the light-emitting device of the present invention has stable optical characteristics over a long period and can maintain high reliability.

  Hereinafter, elements, materials and the like used in the light emitting device of the present invention will be described.

[Curable silicone resin]
In the light emitting device of the present invention, the resin layer is provided as a phosphor-containing layer, a lens, a light emitting element protective layer, and the like. This resin layer is comprised by the hardened | cured material of the curable silicone resin containing the said (i)-(d) component. Each component of the composition will be described in detail below. In the following description, the room temperature means 24 ± 2 ° C. unless otherwise specified.
<(I) Organopolysiloxane>
The organopolysiloxane as component (a) is represented by the above average composition formula (1) and has a polystyrene-equivalent weight average molecular weight of 5 × 10 ³ or more.

In the average composition formula (1), examples of the alkyl group represented by R ¹ include a methyl group, an ethyl group, a propyl group, and a butyl group. Examples of the alkenyl group include a vinyl group and an allyl group. Examples of the aryl group include a phenyl group. Among these, a cured product is excellent in heat resistance, ultraviolet resistance, and the like, and therefore, R ¹ is preferably a methyl group.

  Examples of the alkyl group represented by X include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, and an isobutyl group. Examples of alkenyl groups include vinyl groups. Examples of the alkoxyalkyl group include a methoxyethyl group, an ethoxyethyl group, and a butoxyethyl group. Examples of the acyl group include an acetyl group and a propionyl group. Among these, as X, a hydrogen atom, a methyl group, and an isobutyl group are preferable.

  a is preferably a number of 1.15 to 1.25, and b is preferably a number satisfying 0.01 ≦ b <1.4, particularly 0.01 ≦ b ≦ 1.0, and especially O.05 ≦ b ≦ 0.3. When a is less than 1.05, cracks are likely to occur in the obtained cured product, and when it exceeds 1.5, the cured product tends to be brittle without toughness, and has poor heat resistance and ultraviolet resistance. There are things to do. When b is 0, it may be inferior in the adhesiveness with respect to a base material, and when two or more, hardened | cured material may not be obtained. Further, a + b is a number that preferably satisfies 1.06 ≦ a + b ≦ 1.8, more preferably 1.1 ≦ a + b ≦ 1.7.

In addition, since the organopolysiloxane of this component is more excellent in the heat resistance of the cured product, the ratio (mass basis) of R ¹ represented by methyl group or the like in the organopolysiloxane is usually 32. It is preferable to set it as mass% or less, Preferably 15-32 mass%, Especially 20-32 mass%, Especially 25-31 mass% is preferable. If the ratio of R ¹ is too small, the film formability and the crack resistance of the film may be inferior.

The organopolysiloxane of this component has the following general formula (2):
SiR ¹ _c (OR ² ) _4-c (2)
(In the formula, R ¹ is independently as described above, R ² is independently the same as the above X except for a hydrogen atom, and c is an integer of 1 to 3).
By hydrolyzing and condensing the silane compound represented by general formula (2), the silane compound represented by general formula (2) and the following general formula (3):
Si (OR ² ) ₄ (3)
(Wherein R ² is independently the same as described above.)
And / or a polycondensation product of the alkyl silicate (alkyl polysilicate) (hereinafter referred to as “alkyl (poly) silicate”) is obtained by cohydrolysis and condensation.

  These silane compounds and alkyl (poly) silicates may be used alone or in combination of two or more.

  Examples of the silane compound represented by the general formula (2) include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, and dimethyldimethoxysilane. Dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, and the like, preferably methyltrimethoxysilane and dimethyldimethoxysilane. These silane compounds may be used alone or in combination of two or more.

  Examples of the alkyl silicate represented by the general formula (3) include tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetraisopropyloxysilane, and the like, and polycondensates (alkylpolysilicates) of the alkylsilicate. Examples thereof include methyl polysilicate and ethyl polysilicate. These alkyl (poly) silicates may be used alone or in combination of two or more.

  Among these, since the obtained cured product is excellent in crack resistance and heat resistance, the organopolysiloxane of this component is composed of 50 to 95 mol% of alkyltrialkoxysilane such as methyltrimethoxysilane and dimethyldimethoxysilane. Are preferably composed of 50 to 5 mol% of a dialkyl dialkoxysilane such as 75 to 85 mol% of an alkyltrialkoxysilane such as methyltrimethoxysilane and 25 to 15 mol% of a dialkyldialkoxysilane such as dimethyldimethoxysilane. Is more preferable.

  In a preferred embodiment, the organopolysiloxane of this component can be obtained by hydrolyzing and condensing the silane compound, or by cohydrolyzing and condensing the silane compound and an alkyl (poly) silicate. Although the method is not particularly limited, for example, the following conditions can be applied.

  The silane compound and alkyl (poly) silicate are usually preferably used after being dissolved in an organic solvent such as alcohols, ketones, esters, cellosolves, and aromatic compounds. Specifically, for example, alcohols such as methanol, ethanol, isopropyl alcohol, isobutyl alcohol, n-butanol, and 2-butanol are preferable, and the resulting composition has excellent curability and toughness of the cured product. Therefore, isobutyl alcohol is more preferable.

  Furthermore, the silane compound and alkyl (poly) silicate are preferably subjected to hydrolysis and condensation in combination with an acid catalyst such as acetic acid, hydrochloric acid or sulfuric acid. The amount of water added when hydrolyzing and condensing is usually 0.9 to 1.5 mol with respect to 1 mol of the total amount of alkoxy groups in the silane compound or the silane compound alkyl (poly) silicate, Preferably it is 1.0-1.2 mol. When this blending amount satisfies the range of 0.9 to 1.5 mol, the composition has excellent workability and the cured product has excellent toughness.

The weight average molecular weight in terms of polystyrene of the organopolysiloxane of this component is preferably 5 × 10 ³ or more in consideration of pot life from the viewpoint of handling in view of handling because it is desirable that the molecular weight is brought to the molecular weight just before gelation by aging. Is required, preferably 5 × 10 ^{3 to} 3 × 10 ⁶ , particularly preferably 1 × 10 ⁴ to 1 × 10 ⁵ . When this molecular weight is less than 5 × 10 ³ , cracks are likely to occur when the resulting composition is cured. In addition, when this molecular weight is too large, this composition is easily gelled and the workability may be inferior.

  The aging temperature is preferably 0 to 40 ° C., more preferably room temperature. When this aging temperature is 0 to 40 ° C., the organopolysiloxane of this component has a ladder-like structure, so that the resulting cured product has excellent crack resistance.

  The (a) component organopolysiloxane may be used alone or in combination of two or more.

<(B) Condensation catalyst>
The condensation catalyst as component (b) is a component required for curing the organopolysiloxane as component (a). Although it does not specifically limit as a condensation catalyst, Since it is excellent in stability of the said organopolysiloxane, the hardness of hardened | cured material, UV resistance, etc., an organometallic catalyst is normally used. Examples of the organometallic catalyst include those containing atoms such as zinc, aluminum, titanium, tin, and cobalt, and those containing zinc, aluminum, and titanium atoms are preferable. Specific examples thereof include organic acid zinc, Lewis acid catalyst, organic aluminum compound, organic titanium compound and the like, and more specifically, for example, zinc octylate, zinc benzoate, zinc p-tert-butylbenzoate. , Zinc laurate, zinc stearate, aluminum chloride, aluminum perchlorate, aluminum phosphate, aluminum triisopropoxide, aluminum acetylacetonate, aluminum butoxybisethyl acetoacetate, tetrabutyl titanate, tetraisopropyl titanate, tin octylate , Cobalt naphthenate, tin naphthenate and the like, preferably zinc octylate.

  (B) The amount of component is usually 0.05 to 10 parts by weight per 100 parts by weight of component (a), and the resulting composition is excellent in curability and stability, preferably 0.1 to 5 parts by mass. The component (b) component condensation catalyst may be used alone or in combination of two or more.

<(C) Solvent>
The solvent which is the component (c) is required particularly for improving the moldability of the cured product when the composition is screen-printed. The solvent is not particularly limited, but has a boiling point of preferably 64 ° C. or higher, more preferably 70 to 230 ° C., and particularly preferably 80 to 200 ° C. When the above range is satisfied, when the screen printing is performed, the composition or the cured product is free from bubbles (voids) due to bubbles and the surface whitening phenomenon is eliminated, so that a good molded product can be obtained.

  Examples of the solvent for this component include hydrocarbon solvents such as benzene, toluene and xylene; ether solvents such as tetrahydrofuran, 1,4-dioxane and diethyl ether; ketone solvents such as methyl ethyl ketone; chloroform, methylene chloride, 1 Halogen solvents such as 1,2-dichloroethane; alcohol solvents such as methanol, ethanol, isopropyl alcohol and isobutyl alcohol; organic solvents having a boiling point of less than 150 ° C. such as octamethylcyclotetrasiloxane and hexamethyldisiloxane, cellosolve acetate, Preferred examples include organic solvents having a boiling point of 150 ° C or higher, such as cyclohexanone, butyl cellosolve, methyl carbitol, carbitol, butyl carbitol, diethyl carbitol, cyclohexanol, diglyme, and triglyme. Include xylene, isobutyl alcohol, diglyme, and triglyme.

  These organic solvents may be used alone or in combination of two or more. However, since the leveling property of the coating surface of the composition is improved, it is preferable to use two or more in combination. Furthermore, it is particularly preferable to contain at least one organic solvent having a boiling point of 150 ° C. or higher because the composition is cured well during screen printing of the composition and a cured product having excellent workability can be obtained. In particular, in this component, the organic solvent having a boiling point of 150 ° C. or higher is preferably 5 to 30% by mass, more preferably 7 to 20% by mass, and further preferably 8 to 15% by mass. .

  The amount of component (c) is not particularly limited, but is preferably 233 parts by mass or less, more preferably 10 to 100 parts by mass, and particularly preferably 20 to 80 parts by mass with respect to 100 parts by mass of component (b). It is. That is, the content of the component (a) relative to the sum of the components (a) and (c) is preferably 30% by mass or more, more preferably 50 to 91% by mass, and particularly preferably 55 to 83% by mass. When such a range is satisfied, the moldability of the cured product becomes better, and the thickness of the cured product is typically 10 μm to 3 mm, more typically 100 μm to 3 mm in a dry state. It becomes easy to process.

<(D) Fine powder inorganic filler>
The fine powder inorganic filler as component (d) imparts thixotropy necessary for screen printing to the composition. Further, by blending the inorganic filler, the light scattering of the cured product (for example, low birefringence) and the fluidity of the composition are in an appropriate range, or the material using the composition has high strength. There is an effect such as.

The specific surface area (BET specific surface area) of the fine powder inorganic filler by the BET method is not particularly limited. For example, when the composition is used for screen printing, it is 100 m ² / g or more (usually 100 to 400 m ² / it is preferably g), more preferably 180 m ^{2 /} g or more, and particularly preferably 200~350m ^{2 /} g. If this range is satisfied, good thixotropy can be obtained for maintaining moldability, so that the blending amount of this component can be reduced.

  The inorganic filler constituting the fine powder inorganic filler is not particularly limited. For example, silica, alumina, aluminum hydroxide, titanium oxide, bengara, calcium carbonate, magnesium carbonate, aluminum nitride, magnesium oxide, zirconium oxide, and nitride Examples thereof include boron and silicon nitride. Generally, silica is suitably used because the particle size, purity and the like are appropriate.

  The silica, that is, fine powder silica, may be a known one, and may be wet silica or dry silica. Specific examples thereof include precipitated silica, silica xerogel, fumed silica, fused silica, crystalline silica, or the surface of which is hydrophobized with an organic silyl group. As these commercial products, for example, Aerosil (manufactured by Nippon Aerosil Co., Ltd.), Nipsil (manufactured by Nippon Silica Co., Ltd.), Cabosil (manufactured by Cabot Corporation in the United States), Santo Cell (manufactured by Monsanto Corporation in the United States), etc. Can be mentioned.

  Although the compounding quantity of (d) component is not specifically limited, Preferably it is 5-40 mass parts with respect to 100 mass parts of said (b) component, More preferably, it is 15-25 mass parts, Most preferably, it is 18-20 mass. Part. When this range is satisfied, the composition not only has good workability but also has sufficient thixotropy necessary for screen printing.

  (D) The fine powder inorganic filler of the component may be used alone or in combination of two or more.

<Other ingredients>
In addition to the above-mentioned components (A) to (D), other components can be added to the present composition as long as the effects and effects of the present invention are not impaired. Other components may be used alone or in combination of two or more.

-Phosphor-
The phosphor is a typical optional component added to the present composition as necessary.

Examples of the phosphor include yttrium / aluminum garnet-based YAG phosphor, ZnS phosphor, Y ₂ O ₂ S phosphor, red light-emitting phosphor, and blue light-emitting phosphor widely used in LEDs. And green light emitting phosphors. Hereinafter, typical phosphors will be described in more detail.

First, a phosphor based on a cerium-activated yttrium / aluminum oxide phosphor capable of emitting light by exciting light emitted from the light emitting element can be given.
Specific examples of the yttrium / aluminum oxide phosphor include YAlO ₃ : Ce, Y ₃ Al ₅ O ₁₂ : Ce (YAG: Ce), Y ₄ Al ₂ O ₉ : Ce, and a mixture thereof. It is done. The yttrium / aluminum oxide phosphor may contain at least one of Ba, Sr, Mg, Ca, and Zn. Moreover, by containing Si, the reaction of crystal growth can be suppressed and phosphor particles can be aligned.

  In this specification, the yttrium-aluminum oxide phosphor activated with Ce is to be interpreted in a broad sense, and part or all of yttrium is from the group consisting of Lu, Sc, La, Gd, and Sm. It is substituted with at least one element selected, or a part or the whole of aluminum is substituted with one or more of Ba, Tl, Ga and In, or both yttrium and aluminum are so substituted and have a fluorescent action. It is used in a broad sense including phosphors having

More specifically, the general formula _{(Y z Gd 1-z)} 3 Al 5 O 12: Ce ( where, 0 <z ≦ 1) photoluminescence phosphor and the general formula represented by _{(Re 1-a Sm a)} 3 Re ' ₅ O ₁₂ : Ce (where 0 ≦ a <1, 0 ≦ b ≦ 1, Re is at least one selected from Y, Gd, La, and Sc, and Re ′ is selected from Al, Ga, and In. At least one kind of photoluminescent phosphor.

  Since this phosphor has a garnet structure (garnet-type structure), it is resistant to heat, light, and moisture, and the peak of the excitation spectrum can be made around 450 nm. The emission peak is also in the vicinity of 580 nm and has a broad emission spectrum that extends to 700 nm.

  Further, the photoluminescence phosphor can increase the excitation light emission efficiency in a long wavelength region of 460 nm or more by containing Gd (gadolinium) in the crystal. As the Gd content increases, the emission peak wavelength shifts to a longer wavelength, and the entire emission wavelength also shifts to the longer wavelength side. That is, when a strong reddish emission color is required, it can be achieved by increasing the amount of Gd substitution. On the other hand, as Gd increases, the emission luminance of photoluminescence by blue light tends to decrease. Furthermore, in addition to Ce, Tb, Cu, Ag, Au, Fe, Cr, Nd, Dy, Co, Ni, Ti, Eu, and the like can be contained as desired.

  In addition, in the composition of the yttrium / aluminum / garnet (garnet) phosphor having a garnet structure, the emission wavelength is shifted to the short wavelength side by substituting part of Al with Ga. Further, by substituting part of Y in the composition with Gd, the emission wavelength is shifted to the longer wavelength side.

  When substituting a part of Y with Gd, it is preferable that the substitution with Gd is less than 10%, and the Ce content (substitution) is 0.03 to 1.0. If the substitution with Gd is less than 20%, the green component is large and the red component is small. However, by increasing the Ce content, the red component can be supplemented and a desired color tone can be obtained without lowering the luminance. With such a composition, the temperature characteristics are good and the reliability of the light emitting diode can be improved. In addition, when a photoluminescent phosphor adjusted to have a large amount of red component is used, a light emitting device capable of emitting an intermediate color such as pink can be formed.

  Such photoluminescent phosphors use oxides or compounds that easily become oxides at high temperatures as raw materials for Y, Gd, Al, and Ce, and mix them well in a stoichiometric ratio. Get raw materials. Alternatively, a mixed raw material obtained by mixing a coprecipitation oxide obtained by firing a solution obtained by coprecipitation of a solution obtained by dissolving a rare earth element of Y, Gd, and Ce in an acid in a stoichiometric ratio with oxalic acid and aluminum oxide. Get. An appropriate amount of fluoride such as barium fluoride or ammonium fluoride is mixed as a flux and packed in a crucible, and baked in air at a temperature range of 1350 ° C. to 1450 ° C. for 2 to 5 hours to obtain a fired product, and then fired. The product can be obtained by ball milling in water, washing, separating, drying and finally passing through a sieve.

  Such a photoluminescent phosphor may be a mixture of yttrium, aluminum, garnet (garnet) phosphor activated by two or more kinds of cerium, and other phosphors.

  The particle size of the phosphor is preferably in the range of 1 μm to 50 μm, more preferably 3 μm to 30 μm. A phosphor having a particle size of less than 3 μm is relatively easy to form an aggregate, and is likely to become dense and settle in the liquid resin, thus reducing the light transmission efficiency. When the particle diameter is in the above preferred range, the light concealment by such a phosphor can be suppressed and the output of the light emitting device is improved. In addition, phosphors in the same particle size range have high light absorptivity and conversion efficiency and a wide excitation wavelength range. Thus, by including a large particle size phosphor having optically excellent characteristics, light around the main wavelength of the light emitting element can be well converted and emitted.

  Here, the particle size is a value obtained from a volume-based particle size distribution curve. The volume-based particle size distribution curve can be obtained by measuring the particle size distribution by a laser diffraction / scattering method. Specifically, in an environment of an air temperature of 25 ° C. and a humidity of 70%, hexametalin having a concentration of 0.05%. Each substance was dispersed in a sodium acid aqueous solution and measured with a laser diffraction particle size distribution analyzer (SALD-2000A) in a particle size range of 0.03 μm to 700 μm. In this volume-based particle size distribution curve, it is a particle size value when the integrated value is 50%, and the center particle size of the phosphor used in the composition is preferably in the range of 3 μm to 30 μm. Moreover, it is preferable that the fluorescent substance which has this center particle size value is contained with high frequency, and the frequency value is preferably 20% to 50%. In this way, by using a phosphor having a small variation in particle size, a light emitting device having a good color tone can be obtained with reduced chromaticity variation for each product.

  The phosphor is preferably dispersed uniformly in the resin layer, but the phosphor may be precipitated in the resin layer.

Moreover, it is not restricted to the said YAG fluorescent substance, Various fluorescent substance can be used. For example, M ₂ Si ₅ N ₈ : Eu (M is an alkaline earth metal such as Ca, Sr and Ba) and MSi ₂ O ₂ N ₂ : Eu (M is an alkali such as Ca, Sr and Ba). An earth metal), La ₂ O ₂ S: Eu, SrAl ₂ O ₄ : R, M ₅ (PO ₄ ) ₃ X: R (M is at least selected from Sr, Ca, Ba, Mg, Zn) X is at least one selected from F, Cl, Br, and I. R is Eu, Mn, or any one of Eu and Mn. Can do.
As other phosphors, alkaline earth metal silicates activated with europium can also be contained. The alkaline earth metal silicate is preferably an alkaline earth metal orthosilicate represented by the following general formula.

(2-x-y) SrO · x (Ba, Ca) O · (1-a-b-c-d) SiO 2 · aP 2 O 5 bAl 2 O 3 cB 2 O 3 dGeO 2: yEu 2+ ( Equation Medium, 0 <x <1.6, 0.005 <y <0.5, 0 <a, b, c, d <0.5.)

(2-x-y) BaO · x (Sr, Ca) O · (1-a-b-c-d) SiO 2 · aP 2 O 5 bA1 2 O 3 cB 2 O 3 dGeO 2: yEu 2+ ( Equation (Inside, 0.01 <x <1.6, 0.05 <y <0.5, 0 <a, b, c, d <0.5.)

  Here, preferably, at least one of the values of a, b, c and d is greater than 0.01.

As a phosphor composed of an alkaline earth metal salt, in addition to the above alkaline earth metal silicate, alkaline earth metal aluminate or Y (V, P, Si) O ₄ activated with europium and / or manganese. : Eu or an alkaline earth metal-magnesium-disilicate represented by the following formula can also be contained.

Me (3-xy) MgSi ₂ O ₃ : xEu, yMn (wherein 0.005 <x <0.5, 0.005 <y <0.5, Me represents Ba and / or Sr and / or Or Ca.)

  The phosphor made of the above alkaline earth metal silicate is manufactured as follows. Depending on the alkaline earth metal silicate of the desired composition of interest, the stoichiometric amounts of the starting alkaline earth metal carbonate, silicon dioxide and europium oxide are intimately mixed and used routinely for the production of phosphors. It is a solid reaction and is converted to the desired phosphor at temperatures of 1100 ° C. and 1400 ° C. under a reducing atmosphere. At this time, it is preferable to add less than 0.2 mol of ammonium chloride or other halide. If necessary, part of silicon can be replaced with germanium, boron, aluminum, and phosphorus, and part of europium can be replaced with manganese.

One of the phosphors as described above, ie, alkaline earth metal aluminates activated with europium and / or manganese, Y (V, P, Si) O ₄ : Eu, Y ₂ O ₂ S: Eu ³⁺ By combining one or these phosphors, an emission color having a desired color temperature and high color reproducibility can be obtained.

―Diffusion agent―
Another optional component that may be added to the curable silicone resin is a diffusing agent. By containing a diffusing agent, a light diffusing effect, a thickening effect, a stress diffusing effect, and the like can be obtained. As a specific diffusing agent, barium titanate, titanium oxide, aluminum oxide, silicon oxide or the like is preferably used. As a result, a light emitting device having good directivity can be obtained. The diffusing agent preferably has a center particle size of 1 nm or more and less than 5 μm. A diffusing agent having a center particle diameter of about 400 nm or more can diffuse light from the light emitting element and the phosphor well, and can suppress color unevenness that tends to occur when a phosphor having a large particle diameter is used. On the other hand, a diffusing agent having a center particle diameter of less than about 400 nm has a low interference effect on the light wavelength from the light emitting element, and thus has high transparency, and can increase the resin viscosity without reducing the light intensity. Thus, when the color conversion member is arranged by potting or the like, it becomes possible to disperse the phosphor in the resin composition almost uniformly in the syringe and maintain the state, and the particle size is relatively difficult to handle. Even when a large phosphor is used, it is possible to produce with high yield. Thus, since the action of the diffusing agent varies depending on the particle size range, it is desirable to select or use it in combination with the method of use.

―Other optional ingredients―
Furthermore, other optional components include, for example, anti-aging agents, radical inhibitors, ultraviolet absorbers, adhesion improvers, flame retardants, surfactants, storage stability improvers, ozone degradation inhibitors, light stabilizers, Sticky agent, plasticizer, coupling agent, antioxidant, heat stabilizer, conductivity enhancer, antistatic agent, radiation blocking agent, nucleating agent, phosphorus peroxide decomposer, lubricant, pigment, metal deactivation Agents, physical property modifiers and the like.

-Preparation method of the composition-
The curable silicone resin composition can be prepared by mixing the components (a) to (d) and other components optionally contained by any method. Specifically, for example, (a) the organopolysiloxane, (c) the solvent, and (d) the fine powder inorganic filler are mixed with three rolls to obtain a mixture. Then, the composition can be prepared by mixing this mixture with the condensation catalyst of component (b) and other components in a mixer such as THINKY CONDITIONING MIXER (manufactured by Shinky Co., Ltd.). It is desirable to appropriately perform a defoaming operation at each stage of composition preparation.

[Screen printing and curing methods]
A method of applying the composition to the surface of the light emitting element by screen printing will be described. First, the surface of the light emitting element is covered with a mask having openings of a required pattern, and the composition is put into the squeegee portion. Next, the composition is filled in the openings of the masking member by moving the squeegee and moving the mask while pressing the composition (filling step). Next, the mask is removed. Thus, the surface of the light emitting element is coated with the composition.
In general, the above-mentioned composition depends on conditions actually employed for screen printing, such as squeegee speed, printing pressure, clearance (gap between the mask during printing and the printing surface), squeegee angle, and pressing amount. The viscosity at 23 ° C. is preferably 1 × 10 Pa · s to 1 × 10 ⁵ Pa · s, more preferably 50 Pa · s to 2000 Pa · s (DV-II digital viscometer manufactured by Brookfield, USA, using a rotation speed of 0.3 rpm) The thixo coefficient is preferably from 1.0 to 15.0, more preferably from 3.0 to 9.0.

  The composition layer thus formed is then cured. Curing is preferably step-cured, for example, heated at 60-100 ° C. (eg, 1-2 hours), then heated at 120-160 ° C. (eg, 1-2 hours), and further 180-220 It is cured by heating at 0 ° C. (for example, 6 to 12 hours). By the step cure through these steps, the composition is sufficiently cured, and the cured product is appropriately suppressed from generating bubbles. As described above, the thickness of the obtained cured resin layer is typically 10 μm to 3 mm, more typically 100 μm to 3 mm in a dry state.

  The glass transition point (Tg) of the cured product obtained by curing the composition is usually a commercially available measuring instrument (for example, thermomechanical tester (trade name: TM-7000, measurement range manufactured by Vacuum Riko Co., Ltd.). : 25 to 200 ° C.)), the cured product is extremely excellent in heat resistance.

[Light emitting element]
In the present invention, the light-emitting element is not particularly limited, and is not limited to a light-emitting element that emits red or green light. A light-emitting element that emits blue light can also be used. Further, not only these light emitting elements that emit visible light but also light emitting elements that emit light in the ultraviolet region from the short wavelength region of visible light, for example, light emitting devices that emit light in the ultraviolet region near 360 nm can be used. However, when a phosphor is used for the light emitting device, a semiconductor light emitting element having a light emitting layer capable of emitting a light emission wavelength capable of exciting the phosphor is preferable. Examples of such semiconductor light emitting devices include various semiconductors such as ZnSe and GaN, but nitride semiconductors (InxAl _Y Ga _1-XY N, 0 ≦ X, 0 ≦ Y, X + Y ≦ 1) are preferred. If desired, the nitride semiconductor may contain boron or phosphorus. Examples of the semiconductor structure include a homostructure having a MIS junction, a PIN junction, a pn junction, or the like, a heterostructure, or a double heterostructure. Various emission wavelengths can be selected depending on the material of the semiconductor layer and the degree of mixed crystal. In addition, a single quantum well structure or a multiple quantum well structure in which the semiconductor active layer is formed in a thin film in which a quantum effect is generated can be used.

  When a nitride semiconductor is used, materials such as sapphire, spinel, SiC, Si, ZnO, and GaN are preferably used for the semiconductor substrate. In order to form a nitride semiconductor with good crystallinity with high productivity, it is preferable to use a sapphire substrate. A nitride semiconductor can be formed on the sapphire substrate by MOCVD or the like. A buffer layer of GaN, AlN, GaAlN or the like is formed on the sapphire substrate, and a nitride semiconductor having a pn junction is formed thereon.

  As an example of a light emitting device having a pn junction using a nitride semiconductor, a first contact layer formed of n-type gallium nitride, a first cladding layer formed of n-type aluminum nitride / gallium on a buffer layer, nitrided Examples include a double hetero configuration in which an active layer formed of indium gallium, a second cladding layer formed of p-type aluminum nitride / gallium, and a second contact layer formed of p-type gallium nitride are sequentially stacked.

  A nitride semiconductor exhibits n-type conductivity without being doped with impurities. When forming a desired n-type nitride semiconductor, for example, to improve luminous efficiency, it is preferable to appropriately introduce Si, Ge, Se, Te, C, etc. as an n-type dopant. On the other hand, when forming a p-type nitride semiconductor, the p-type dopants such as Zn, Mg, Be, Ca, Sr, and Ba are doped. Since nitride semiconductors are not easily converted to p-type by simply doping with a p-type dopant, it is preferable to reduce resistance by heating in a furnace or plasma irradiation after introducing the p-type dopant. After the electrodes are formed, a light emitting element made of a nitride semiconductor can be formed by cutting the semiconductor wafer into chips.

  In the light emitting device, in order to emit white light, the emission wavelength of the light emitting element is preferably 400 nm or more and 530 nm or less, considering the complementary color relationship with the emission wavelength from the phosphor or the deterioration of the translucent resin, and 420 nm or more. 490 nm or less is more preferable. In order to further improve the excitation and emission efficiency of the light emitting element and the phosphor, 450 nm or more and 475 nm or less are more preferable.

  Hereinafter, the light emitting device of the present invention will be described in more detail with reference to embodiments shown in the drawings. The light emitting device of this embodiment is a type in which an LED as a light emitting element is flip-chip mounted on a submount and hermetically sealed with a lid that also serves as a glass lens, but this is an example, and the light emitting device of the present invention Is not limited to this embodiment. Other types include, for example, a type in which a screen-printed light-emitting element is further covered with a resin such as silicone, a type that is not airtight but covered with a glass lens lid, and a type that uses an epoxy resin instead of glass. . In any case, the desired effect can be obtained by providing a resin layer obtained by coating and curing the light-emitting element with the curable silicone resin composition.

Embodiment
Next, the light emitting device of the present invention will be described in accordance with a more specific embodiment.

FIG. 1 is a schematic cross-sectional view of a cut surface perpendicular to the main surface (the surface on which elements are installed) of the support of the light emitting device 100 according to the present embodiment. The dimensions of each component and member are exaggerated for convenience of explanation, and do not necessarily represent actual dimensions and relative ratios.

The light emitting device 100 includes a submount 102 on which the light emitting element 101 is flip-chip mounted, a support 103a that supports the submount 102, and a glass lens 104 that is a translucent member disposed on the main surface side of the support 103a. And have. The glass lens 104 is a hemispherical lens that is convex in a direction in which the light emitting element 101 is viewed when the light emitting device 100 is viewed from above, and whose inner wall surface facing the light emitting element 101 is concave. The light emitting device 100 includes a hollow portion 105 surrounded by the inner wall surface of the glass lens 104 and the main surface of the support 103a, and the light emitting element 101 is hermetically sealed.
FIG. 2 is an enlarged plan view showing only the submount 102 and the light emitting element 101 flip-chip mounted thereon, and FIG. 3 is a front view thereof. The submount 102 is made of an aluminum nitride plate having a thickness of 1 mm, and electrodes 106a and 106b are formed by sputtering using Au as a material. Other examples of the material for the submount include a material obtained by applying a metal pattern to aluminum nitride, a material obtained by patterning an insulating layer such as alumina on a metal material such as Cu, and the like. The light-emitting element 101 has a pair of positive and negative electrodes on the surface facing the submount 102, and these electrodes are welded by applying a load, ultrasonic waves and heat to the electrodes 106a and 106b on the submount 102 through gold bumps. Connected electrically and mechanically.
FIG. 4 is a plan view showing a state in which the light emitting element 101 is signed on each of a large number of hexagonal submounts 102 in this way. This is screen-printed with a resin composition using a mask material having a required opening, and the light emitting element 101 is covered with a resin layer. That is, FIG. 5 is a cross-sectional end view for explaining a screen printing method, in which a metal mask 111 is disposed in close contact with a light-emitting element 101 flip-chip mounted on a submount 102, and resin injected into a squeegee 112. The resin composition 113 is filled in the opening 114 of the metal mask 111 by moving the squeegee 112 in the direction of the arrow 112a. Then remove the metal mask. FIG. 6 is a cross-sectional view showing a state in which the light emitting element 101 flip-chip mounted on the submount 102 is covered with the resin composition 113. Thereafter, the resin composition layer 113 is step-cured under predetermined conditions to form a cured resin layer 114.
In this embodiment, a hollow space 115 is formed between the light emitting element 101 and the submount 102. The space 115 may also be filled with the cured resin layer 114. However, if the space 115 is filled with the cured resin, there may be a problem that the light emitting element 101 is lifted when the cured resin is thermally expanded. If the space 115 is hollow, there is an advantage that this die floating can be prevented. The hollow space 115 can be formed, for example, by adjusting the viscosity of the resin composition 113.
In this way, each light emitting element 101 coated with the resin layer 114 is cut together with the submount 102, and the submount 102 is fixed to the upper surface of the support 103a.
Supports 103b and 103c for supporting the glass lens 104 are joined to the support 103a via an insulating material. The electrode 106a of the submount 102 is connected to the electrode 107 formed on the support 103a, and the electrode 106b is connected to the support 103a. The electrodes 108 provided on the support 103b are electrically connected by wires 109a and 109b, respectively.
The hollow portion 105 is filled with nitrogen gas. The gas enclosed in the hollow portion is air or an inert gas, but an inert gas is preferable to prevent corrosion of the metal material, and may be, for example, nitrogen, argon or helium.

  An aluminum nitride plate having a thickness of about 1.5 mm is used for the supports 103a, 103b, and 103c. The support may be an insulating substrate other than aluminum nitride, such as silicon carbide or BT resin.

-Synthesis example-
Methyltrimethoxysilane used in the following synthesis examples is KBM13 (trade name) manufactured by Shin-Etsu Chemical Co., Ltd., and dimethyldimethoxysilane is KBM22 (trade name) manufactured by Shin-Etsu Chemical Co., Ltd.

<Synthesis Example 1>
A stirrer and a condenser tube were set in a 1 L three-necked flask. In this flask, 109 g (0.8 mol) of methyltrimethoxysilane, 24 g (0.2 mol) of dimethyldimethoxysilane, and 106 g of isobutyl alcohol were added and stirred while cooling with ice. While maintaining the temperature in the system at 0 to 20 ° C., 60.5 g of 0.05N hydrochloric acid solution was added dropwise. After completion of dropping, the mixture was stirred at a reflux temperature of 80 ° C. for 7 hours. Next, the reaction solution was cooled to room temperature, and then diluted with 150 g of xylene. Thereafter, the reaction solution was placed in a separatory funnel and washed with 300 g of water, and washing was continued until the extracted water conductivity of the washing solution became 2.0 μS / cm or less. Then, water is distilled off by azeotropic dehydration of the washed reaction solution, and the volatile content is adjusted to 30% by mass, followed by aging at room temperature for 12 hours to obtain the following formula (4):
(CH ₃ ) _1.2 (OX) _0.25 SiO _1.28 (4)
(In the formula, X is a combination of a hydrogen atom, a methyl group and an isobutyl group)
A mixture of organopolysiloxane 1 (79.1 g) having a weight average molecular weight of 19,000 and 33.9 g of mixed alcohol was obtained.

<Synthesis Example 2>
A stirrer and a condenser tube were set in a 1 L three-necked flask. To this flask, 68.1 g (0.5 mol) of methyltrimethoxysilane, 60.1 g (0.5 mol) of dimethyldimethoxysilane, and 118 g of isobutyl alcohol were added and stirred while cooling with ice. While maintaining the temperature in the system at 0 to 20 ° C., 54 g of 0.05N hydrochloric acid solution was added dropwise. After completion of dropping, the mixture was stirred at a reflux temperature of 80 ° C. for 7 hours. Next, the reaction solution was cooled to room temperature, and then diluted with 150 g of xylene. Thereafter, the reaction solution was placed in a separatory funnel and washed with 300 g of water, and washing was continued until the extracted water conductivity of the washing solution became 2.0 μS / cm or less. Then, by azeotropically dehydrating the washed reaction solution, water is distilled off, the volatile content is adjusted to 30% by mass, and then aging is performed at room temperature for 12 hours to obtain the following formula (5):
(CH ₃ ) _1.5 (OX) _0.22 SiO _1.14 (5)
(In the formula, X is a combination of a hydrogen atom, a methyl group and an isobutyl group)
A mixture of organopolysiloxane 2 (76.3 g) having a weight average molecular weight of 9,000 and 32.7 g of mixed alcohol was obtained.

<Synthesis Example 3>
A stirrer and a condenser tube were set in a 1 L three-necked flask. Into this flask, 115.8 g (0.85 mol) of methyltrimethoxysilane, 18.0 g (0.15 mol) of dimethyldimethoxysilane and 102 g of isobutyl alcohol were added and stirred while cooling with ice. While maintaining the temperature in the system at 0 to 20 ° C., 78.3 g of 0.05N hydrochloric acid solution was added dropwise. After completion of dropping, the mixture was stirred at a reflux temperature of 80 ° C. for 7 hours. Next, the reaction solution was cooled to room temperature, and then diluted with 150 g of xylene. Thereafter, the reaction solution was placed in a separatory funnel and washed with 300 g of water, and washing was continued until the extracted water conductivity of the washing solution became 2.0 μS / cm or less. Then, water is distilled off by azeotropic dehydration of the washed reaction solution, and the volatile content is adjusted to 30% by mass, followed by aging at room temperature for a long time (72 hours). :
(CH ₃ ) _1.15 (OX) _0.23 SiO _1.31 (6)
(In the formula, X is a combination of a hydrogen atom, a methyl group and an isobutyl group)
A mixture of organopolysiloxane 3 (68.6 g) having a weight average molecular weight of 98,000 and 29.4 g of mixed alcohol was obtained.

<Synthesis Example 4>
A stirrer and a condenser tube were set in a 1 L three-necked flask. Into this flask, 27.2 g (0.2 mol) of methyltrimethoxysilane, 96.2 g (0.8 mol) of dimethyldimethoxysilane, and 106 g of isobutyl alcohol were added and stirred while cooling with ice. While maintaining the temperature in the system at 0 to 20 ° C., 57.1 g of 0.05N hydrochloric acid solution was added dropwise. After completion of dropping, the mixture was stirred at a reflux temperature of 80 ° C. for 7 hours. Next, the reaction solution was cooled to room temperature, and then diluted with 150 g of xylene. Thereafter, the reaction solution was placed in a separatory funnel and washed with 300 g of water, and washing was continued until the extracted water conductivity of the washing solution became 2.0 μS / cm or less. Then, by azeotropically dehydrating the washed reaction solution, water is distilled off, and the volatile content is adjusted to 30% by mass, whereby the following formula (7):
(CH ₃ ) _1.8 (OX) _0.22 SiO _0.99 (7)
(In the formula, X is a combination of a hydrogen atom, a methyl group and an isobutyl group)
A mixture of organopolysiloxane C1 (69.3 g) having a weight average molecular weight of 16,000 and 29.7 g of mixed alcohol was obtained.

<Synthesis Example 5>
A stirrer and a condenser tube were set in a 1 L three-necked flask. In this flask, 136.2 g (1.0 mol) of methyltrimethoxysilane and 106 g of isobutyl alcohol were added and stirred while cooling with ice. While maintaining the temperature in the system at 0 to 20 ° C., 81 g of 0.05N hydrochloric acid solution was added dropwise. After completion of dropping, the mixture was stirred at a reflux temperature of 80 ° C. for 7 hours. Next, the reaction solution was cooled to room temperature, and then diluted with 150 g of xylene. Thereafter, the reaction solution was placed in a separatory funnel and washed with 300 g of water, and washing was continued until the extracted water conductivity of the washing solution became 2.0 μS / cm or less. Then, the washed reaction solution is subjected to azeotropic dehydration to distill off water, the volatile content is adjusted to 30% by mass, and the mixture is aged at room temperature for 12 hours to obtain the following formula (8):
(CH ₃ ) _1.0 (OX) _0.24 SiO _1.38 (8)
(In the formula, X is a combination of a hydrogen atom, a methyl group and an isobutyl group)
A mixture of organopolysiloxane C2 (73.5 g) having a weight average molecular weight of 23,000 and 31.5 g of mixed alcohol was obtained.

<Synthesis Example 6>
A stirrer and a condenser tube were set in a 1 L three-necked flask. In this flask, 109 g (0.8 mol) of methyltrimethoxysilane, 24 g (0.2 mol) of dimethyldimethoxysilane, and 106 g of isobutyl alcohol were added and stirred while cooling with ice. While maintaining the temperature in the system at 0 to 20 ° C., 60.5 g of 0.05N hydrochloric acid solution was added dropwise. After completion of dropping, the mixture was stirred at room temperature for 24 hours. Next, 150 g of xylene was added to the resulting reaction solution for dilution. Thereafter, the reaction solution was placed in a separatory funnel and washed with 300 g of water, and washing was continued until the extracted water conductivity of the washing solution became 2.0 μS / cm or less. Then, by azeotropically dehydrating the washed reaction solution, water is distilled off, and the volatile content is adjusted to 30% by mass, whereby the following formula (9):
(CH ₃ ) _1.2 (OX) _1.21 SiO _0.79 (9)
(In the formula, X is a combination of a hydrogen atom, a methyl group and an isobutyl group)
A mixture of organopolysiloxane C3 (67.2 g) having a weight average molecular weight of 3,100 and 28.8 g of mixed alcohol was obtained.

<Synthesis Example 7>
A stirrer and a condenser tube were set in a 1 L three-necked flask. Into this flask, 40.9 g (0.3 mol) of methyltrimethoxysilane, 170.8 g (0.7 mol) of diphenyldimethoxysilane, and 106 g of isobutyl alcohol were added and stirred while cooling with ice. While maintaining the temperature in the system at 0 to 20 ° C., 55.1 g of 0.05N hydrochloric acid solution was added dropwise. After completion of dropping, the mixture was stirred at a reflux temperature of 80 ° C. for 7 hours. Next, the reaction solution was cooled to room temperature, and then diluted with 150 g of xylene. Thereafter, the reaction solution was placed in a separatory funnel and washed with 300 g of water, and washing was continued until the extracted water conductivity of the washing solution became 2.0 μS / cm or less. Then, by azeotropically dehydrating the washed reaction solution, water is distilled off, and the volatile content is adjusted to 30% by mass, whereby the following formula (10):
(CH ₃ ) _0.3 (C ₆ H ₅ ) _1.4 (OX) _0.16 SiO _1.07 (10)
(In the formula, X is a combination of a hydrogen atom, a methyl group and an isobutyl group)
A mixture of organopolysiloxane C4 (71.4 g) having a weight average molecular weight of 15,400 and 30.6 g of mixed alcohol was obtained.

-Example-
<Examples 1-11, Comparative Examples 1-8>
Organopolysiloxanes 1 to 3, C1 to C4 obtained in Synthesis Examples 1 to 7, C1 to C4, a condensation catalyst, a solvent (including the above mixed alcohol) and a fine powder inorganic filler are blended in the proportions shown in Table 1, and the composition Was prepared. The screen printability of this composition and the properties (crack resistance, adhesiveness, ultraviolet resistance, heat resistance) of the cured product (cured film) obtained by curing the composition were tested and evaluated according to the following evaluation methods. evaluated.

<Evaluation method>
―1. Screen printability
The obtained composition was squeezed into a stainless steel mold test pattern (10 mm × 10 mm × 0.2 mm, 5 mm × 5 mm × 0.2 mm, 2 mm × 2 mm × 0.2 mm), applied, and then at 80 ° C. for 1 hour, By performing step cure at 150 ° C. for 1 hour and further at 200 ° C. for 1 hour, a cured film (approximately square shape) having a dry thickness of 0.15 mm was produced. The appearance of this cured film was visually observed. When the corner portion of the square cured film is not abnormal (no roundness), the screen printability is evaluated as good and indicated by A, and the corner portion of the square cured film is slightly rounded The screen printability is evaluated as slightly good and is indicated by B, and when the corner portion of the square cured film is extremely rounded, the screen printability is evaluated as poor and indicated by C.

-2. Crack resistance
The obtained composition is put into a mold (50 mm × 50 mm × 2 mm) coated with Teflon (registered trademark) and subjected to step cure at 80 ° C. for 1 hour, then at 150 ° C. for 1 hour, and further at 200 ° C. for 1 hour. Then, a cured film having a thickness of 1 mm in a dry state was produced by post-curing at 200 ° C. for 8 hours. The presence or absence of cracks in the cured film was visually observed. A case where no crack is observed in the cured film is evaluated as A when the crack resistance is good, and a case where a crack is observed is evaluated as B when the crack resistance is poor. Moreover, when the said cured film was not able to be produced, it shows as C that measurement is impossible.

―3. Adhesiveness-
The obtained composition was applied to a glass substrate by a dipping method, followed by step curing at 80 ° C. for 1 hour, then at 150 ° C. for 1 hour, and further at 200 ° C. for 1 hour, and then post-cure at 200 ° C. for 8 hours. As a result, a cured film having a thickness of 2 to 3 μm in a dry state was formed on the glass substrate. The adhesion of the cured film to the glass substrate was examined by a gobang test. In the gobang test, the hardened film formed on the glass substrate is cut into a fixed gobang (1 mm x 1 mm) so that it reaches the substrate with a sharp blade, and adhesive tape is applied to the surface and pressed firmly. After that, the end of the tape was quickly pulled vertically apart. The number of Gobang eyes that did not peel off among all Gobang eyes (100) is shown in the table. Moreover, when the adhesiveness cannot be measured due to the occurrence of cracks in the cured film, it is indicated as x in the table.

―4. UV resistance
The obtained composition was placed in a mold (40 mm × 20 mm × 0.4 mm) coated with Teflon (registered trademark) and subjected to step cure at 80 ° C. for 1 hour, then at 150 ° C. for 1 hour, and further at 200 ° C. for 1 hour. After that, a cured film having a thickness of 0.2 mm in a dry state was prepared by post-curing at 200 ° C. for 8 hours. The cured film was subjected to UV irradiation (output: 30 mW) for 24 hours using a UV irradiation device (trade name: Eye Ultraviolet Curing Device, manufactured by Eye Graphics Co., Ltd.). The surface of the cured film after UV irradiation was visually observed. When the surface of the cured film is not deteriorated at all, the UV resistance is evaluated as good and indicated as A, and when the deterioration is slightly observed, the UV resistance is evaluated as slightly poor as B. A case where remarkable deterioration was observed was evaluated as being poor in ultraviolet resistance and indicated as C. Moreover, when the said cured film was not able to be produced, it shows as x as measurement impossibility.

―5. Heat-resistant-
The obtained composition is put into a mold (50 mm × 50 mm × 2 mm) coated with Teflon (registered trademark) and subjected to step cure at 80 ° C. for 1 hour, then at 150 ° C. for 1 hour, and further at 200 ° C. for 1 hour. Then, a cured film having a thickness of 1 mm in a dry state was produced by post-curing at 200 ° C. for 8 hours. This cured film was placed in an oven at 250 ° C., and the remaining mass after 500 hours was measured. Using this measurement, the formula:
Residual mass reduction rate = (mass of cured film after 500 hours) / (mass of cured film immediately after production) × 100
The residual mass reduction rate (%) was obtained as an index of heat resistance. Moreover, when the said cured film was not able to be produced, it shows as x as measurement impossibility. In the table, it is shown as heat resistance (%).

<Result>
The results obtained in the above Examples and Comparative Examples are shown in Tables 1 to 3 below.
In the table, the Aerosil 300 was used as the (D) component, a BET specific surface area of 300 meters ² / g fumed silica (manufactured by Nippon Aerosil Co., Ltd.), Cabosil MS-7 is, BET specific surface area of 200 meters ² / g fumed silica (manufactured by Cabot USA). Organopolysiloxane C5 is a polymer having a non-volatile content of approximately 100% obtained by stripping the mixture of organopolysiloxane 1 and mixed alcohol obtained in Synthesis Example 1 and removing the solvent. The methyl group content represents the theoretical amount of methyl groups in the organopolysiloxane. In addition, the unit of the compounding quantity of each component is a mass part.

-Examples 12-15-
In each of the following examples, a light emitting device of the type shown in FIG. 1 was manufactured. The following LED chip was used as the light emitting element 101.
(1) Manufacture of LED chip The used LED chip becomes an n-type contact layer in which a GaN layer as an undoped nitride semiconductor and an Si-doped n-type electrode are formed on a sapphire substrate as a light-transmitting substrate. An n-type GaN layer and a GaN layer that is an undoped nitride semiconductor are stacked, and further, five sets of GaN layers that serve as barrier layers and InGaN layers that serve as well layers are stacked, and finally a GaN layer that serves as a barrier layer Were laminated to make an active layer. The active layer has a multiple quantum well structure. The active layer was formed on the cleaned sapphire substrate by flowing TMG (trimethylgallium) gas, TMI (trimethylindium) gas, nitrogen gas and dopant gas together with a carrier gas, and forming a nitride semiconductor by MOCVD. . A layer to be an n-type nitride semiconductor or a p-type nitride semiconductor was formed by switching between SiH ₄ and Cp ₂ Mg as the dopant gas. Further, an AlGaN layer as a p-type cladding layer doped with Mg and a p-type GaN layer as a p-type contact layer doped with Mg are sequentially stacked on the active layer. A GaN layer is formed on the sapphire substrate at a low temperature to serve as a buffer layer.
The p-type semiconductor is annealed at 400 ° C. or higher after film formation. The LED chip thus fabricated is a nitride semiconductor element having an In _0.2 Ga _0.8 N semiconductor having a monochromatic emission peak at 455 nm which is visible light as the active layer.
Etching exposes the surfaces of the p-type contact layer and the n-type contact layer on the same side of the nitride semiconductor on the sapphire substrate. Next, sputtering using ITO (complex oxide of indium and tin) as a material is performed on the p-type contact layer, and a stripe-shaped diffusion electrode is provided on almost the entire surface of the p-type contact layer. By setting it as such an electrode, the electric current which flows through a diffused electrode can be spread over the wide range of a p-type contact layer, and the luminous efficiency of an LED chip can be improved.

Furthermore, sputtering using Rh / Pt / Au and W / Pt / Au as materials is sequentially performed on a part of the p-side diffusion electrode and the n-type contact layer, and is laminated as a metal layer. n side pedestal electrode. Finally, a wafer on which semiconductors are stacked and the above electrodes are formed is formed into chips by dicing to obtain LED chips of □ = 1 mm × 1 mm. In this embodiment, the n-type pedestal electrode formed on the n-type semiconductor exposed in a stripe shape is exposed from the insulating protective film (SiO ₂ ) on the two opposite sides of the LED chip. Further, the n-type semiconductor exposed by etching has a constricted portion that narrows from the position of the corner where the n-type pedestal electrode is exposed toward the center of the LED chip when viewed from the upper surface direction of the LED chip. Moreover, it has an extending | stretching part so that a pair of constricted part which mutually opposes may be tied. Further, the p-side semiconductor layer and the diffusion electrode are disposed at a position sandwiching the extending portion, or the P-side pedestal electrode is exposed from the protective film.

(2) Mounting on Submount As shown in FIGS. 1, 2 and 3, the LED chip 101 has p-side and n-side pedestal electrodes on the conductor electrodes 106a and 106b of the submount 102 via Au bumps. The bumps are welded to the electrodes 106 a and 106 b by applying a load, ultrasonic waves, and heat, and are bonded to the submount 102.

(3) Preparation of phosphor Co-precipitated oxide obtained by co-precipitation with oxalic acid of a solution obtained by dissolving rare earth elements of Y, Gd, and Ce in acid at a stoichiometric ratio with oxalic acid, aluminum oxide, To obtain a mixed raw material. Further, barium fluoride is mixed as a flux, then packed in a bank, and fired in air at a temperature of 1400 ° C. for 3 hours to obtain a fired product. The fired product is ball _milled in water, washed, separated, dried, and finally passed through a sieve to have a center particle size of 8 μm (Y _0.995 Gd _0.005 ) _2.750 Al ₅ O ₁₂ : Ce _0.250 phosphor (So-called YAG phosphor) is formed.

(4) Base composition for screen printing The following compositions A and B were prepared as base compositions for screen printing.
<Composition A>
The composition which is the same as the composition which concerns on the said Example 1, except that the zinc octylate (condensation catalyst) of (b) component is not added.
<Composition B>
A composition obtained by further adding an alkoxysilane coupling agent to the composition A.

<Example 12>
A white light emitting device was manufactured by the following procedure using the LED mounted on the submount.

  The base composition A (5 g) and the YAG phosphor (5 g) were weighed into a predetermined container, mixed and stirred for 3 minutes, and then degassed for 1 minute. Next, 0.5 g of zinc octylate was added as a catalyst to the obtained mixture, and the mixture was further stirred and mixed for 3 minutes, and then degassed for 1 minute. Thus, a phosphor-containing silicone resin paste was obtained. The paste had a viscosity (23 ° C.) of 70 Pa · s.

As shown in FIG. 4, the paste was applied by screen printing to an LED flip-chip mounted on a number of submounts using a commercially available printer. That is, a metal mask having a predetermined opening pattern was brought into close contact with the LED, the paste was applied by the method described above with reference to FIG. 5, and the LED was formed as shown in FIG. Next, the molded product was heated at 80 ° C. for 1 hour to be cured at low temperature, then heated and cured at 150 ° C. for 1 hour, and further heated and cured at 200 ° C. for 8 hours. Thus, a phosphor-containing silicone resin layer 114 having a thickness of 60 μm was formed around the light emitting element 101, and a white light emitting element was manufactured.
Then, each LED was cut off together with the submount 102, and the submount 102 was fixed to the support body 103a. Furthermore, the electrodes 106a and 106b of the submount 102 were electrically connected to the electrode 107 provided on the support body 103a and the electrode 108 provided on the support body 103b through wires.
On the other hand, an epoxy resin (manufactured by Shin-Etsu Chemical Co., Ltd.) was printed on the edge of the glass lens 104 where the glass lens 104 was in contact with the supports 103b and 103c, and B-stage was formed by heat treatment at 100 ° C. for 1 hour.
Next, the glass lens 104 was placed on a package on which the white light emitting element (resin layer-covered light emitting element) was mounted, and then heat-cured at 150 ° C. for 10 minutes to be hermetically sealed. In this way, a white light emitting device was obtained.

<Example 13>
A white light emitting device was produced in the same manner as in Example 12 except that the base composition B was used instead of the base composition A.
<Example 14>
A light emitting device was manufactured in the same manner as in Example 12 except that the YAG phosphor was not added.

<Example 15>
A light emitting device was manufactured in the same manner as in Example 13 except that the YAG phosphor was not added.

―Evaluation of characteristics―
The white light emitting devices manufactured in Examples 12 and 13 were kept lit under the following three driving conditions, and the output retention rate and color tone retention rate with respect to the initial values after 1000 hours were measured and evaluated according to the following criteria. . The results are shown in Table 4. High reliability was shown.
・ Drive conditions:
(1) A current of 700 mA is applied in a constant temperature bath at a temperature of 85 ° C. and a humidity of 85%.
(2) A current of 700 mA is applied in a constant temperature bath at a temperature of 60 ° C. and a humidity of 90%.
(3) A current of 700 mA is passed in a room with a temperature of 25 ° C. and a humidity of about 50%.
・ Criteria:
.. Output maintenance ratio: 70% or more of the initial value is evaluated as “good”.
-Color tone maintenance rate: Both Δx and Δy are evaluated as “good” within ± 0.005 of the initial value.

It is an end view of the longitudinal section which shows one Embodiment of the light-emitting device of this invention. It is a top view which shows the light emitting element flip-chip mounted in the submount. FIG. 3 is a front view of the light emitting device shown in FIG. The top view which shows many light emitting elements formed in each of many submounts. It is an end elevation of the longitudinal section explaining the process of coat | covering the light emitting element on a submount by screen printing. It is a longitudinal cross-sectional view which shows the state by which the light emitting element on a submount was coat | covered with the resin layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Light-emitting device 101 Light-emitting element 102 Submount 104 Glass lens 111 Metal mask 112 Squeegee 113 Curable silicone resin composition 114 Resin layer 115 Cavity space

Claims (8)

A light-emitting element and a resin layer screen-printed to cover the light-emitting element;
The resin layer is
(I) The following average composition formula (1):
R ¹ _a (OX) _b SiO _{(4-ab) / 2} (1)
Wherein R ¹ is independently an alkyl group having 1 to 6 carbon atoms, an alkenyl group or an aryl group, and X is independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an alkenyl group. An alkoxyalkyl group or an acyl group, a is a number from 1.05 to 1.5, b is a number satisfying 0 <b <2, where a + b is a number satisfying 1.05 <a + b <2.)
An organopolysiloxane having a polystyrene-equivalent weight average molecular weight of 5 × 10 ³ or more,
(B) a condensation catalyst,
(C) A light emitting device comprising a cured product of a curable silicone resin composition containing a solvent and (d) a fine powder inorganic filler. The light emitting device according to claim 1, wherein R ¹ is a methyl group. 3. The light emitting device according to claim ¹ , wherein the ratio of R ^{1 in} the (a) organopolysiloxane is 32% by mass or less.   The light-emitting device according to claim 1, wherein the (b) condensation catalyst is an organometallic catalyst.   The light emitting device according to claim 1, wherein the resin layer has a thickness of 10 μm to 3 mm and is colorless and transparent.   The light emitting device according to claim 1, wherein the light emitting element is flip-chip mounted on a submount substrate, and the light emitting element and the submount substrate are covered with a screen-printed resin layer.   The light emitting device according to claim 6, wherein a hollow space is formed between the submount substrate and the screen printed resin layer.   A method for producing a light-emitting device, comprising: applying the curable silicone resin composition according to claim 1 on a light-emitting element by screen printing; curing the obtained composition layer; and covering the resulting layer with a cured resin layer.

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