JP2006060005A - Light emitting device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable high service durability of a diode and to realize coloring of an arbitrary color by preventing peeling derived from the difference of thermal expansion coefficients in a diode chip, a lead electrode, a conductive wire and a transparent sealing resin, and the operating malfunction of the diode in a light emission device. <P>SOLUTION: The light emitting device consists of a diode chip formed of a light emitting diode (LED) or a laser diode, a conductive wire connecting the lead electrode and the electrode of the diode chip, a binder layer coating the diode chip, and a transparent layer coating the diode chip and the conductive wire on the binder layer. The binder layer is a transparent polyimide silicone resin containing an additive which changes the color tone. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light emitting device and a manufacturing method thereof, and more particularly, to a light emitting diode and a manufacturing method thereof.

  In recent years, light emitting diodes such as LEDs and laser diodes have been put into practical use and are beginning to be used in various fields. Since this light-emitting diode directly converts electric energy into light, it is superior in light emission intensity and durability compared to conventional fluorescent lamps and electrothermal bulbs. These diodes are used as light-emitting devices such as surface-mount types and artillery bullet types. Specifically, diode chips are die-bonded on a substrate that serves as a support, and each electrode of the diode chip is connected to a wire or the like. The diode chip is covered with a transparent sealing resin as desired. (See Patent Document 1)

  As the transparent sealing resin, a resin that is generally insulating and transparent and is liquid at room temperature is used. As a specific example, a thermosetting resin such as an epoxy resin, an acrylate resin, a urethane resin, a silicone resin, or a polyimide resin, or a thermoplastic resin such as an acrylic resin, a polycarbonate resin, or a polynorbornene resin is used. When a thermosetting resin is used, a translucent resin can be formed by heating for resin curing. When a thermoplastic resin is used, the transparent resin can be formed by volatilizing the solvent.

  As a feature of the thermosetting resin, a resin that can be molded by a simple method such as compression molding with a thermosetting reaction at the time of molding can be obtained. About heat resistance, it is generally superior to thermoplastic resin. The thermoplastic resin is characterized by a linear polymer in terms of chemical structure. Moreover, it can process efficiently by extrusion molding and injection molding, and a defective product can be reused. Furthermore, it is easier to mold a transparent resin than a thermosetting resin, and it is excellent in transparency.

  However, this transparent encapsulating resin has a larger linear expansion coefficient than that of the diode chip, and when the transparent encapsulating resin is directly coated on the diode, it is exposed to a high-intensity diode so that the transparent encapsulating resin is exposed at the interface between the diode chip and the encapsulating resin. There are problems such as generation of thermal stress, peeling of the resin, and adversely affecting the operation of the diode.

  Accordingly, it has been proposed to provide a binder layer between the diode and the resin sealing layer. This attempts to solve the problem of thermal stress by using a rubber-like material such as silicone rubber having a low elastic modulus for the binder layer. However, such a silicone rubber has poor adhesion to an epoxy resin that is generally put to practical use as a resin sealing layer, and is still satisfactory when a test such as a heat cycle test is performed. Durability was not obtained.

  Further, the present inventors have proposed a light emitting device having excellent durability by providing a buffer layer made of polyimide silicone between the diode and the resin sealing layer (Japanese Patent Application No. 2003-31039). Then, since the color development depended on the oscillation wavelength of the diode chip material, there was a limit to the color range.

JP 2000-196151 A JP 2002-319709 A

  In the light emitting device having the characteristics of high brightness and high durability, the present invention prevents diode chips, lead electrodes, peeling due to the difference in thermal expansion coefficient between the conductive wire and the transparent sealing resin, and malfunction of the diode, The purpose is to make the diode usable for a long time. It is also an object of the present invention to make it possible to develop an arbitrary color.

  As a result of intensive studies to achieve the above object, the present inventors have found that a binder layer containing a specific transparent polyimide silicone resin and an additive that changes color tone between the diode chip and the transparent sealing resin in the light emitting device. As a result, it was found that the durability was drastically improved, and the present invention was achieved. That is, the light emitting device of the present invention includes a conductive wire for electrically connecting a diode chip, a lead electrode, and an electrode of the diode chip, a binder layer containing an additive for changing the color tone covering the diode chip, and a binder Provided is a light emitting device comprising a transparent resin layer covering the diode chip and the conductive wire on a layer.

  The diode chip is a light emitting diode chip of an LED or a laser diode. The diode chip is composed of a semiconductor light emitting layer such as GaAs, GaP, GaAlAs, GaN, InGaN, or InGaAlN.

  That is, the present invention is a light emitting diode (LED) or a laser diode, and the diode includes a diode chip, a conductive wire for electrically connecting a lead electrode and an electrode of the diode chip, and the diode chip. It comprises a binder layer to be coated, and a sealing resin layer using a transparent epoxy resin that coats the diode chip and the conductive wire on the binder layer, and the binder layer obtains a transparent polyimide silicone resin and an arbitrary color tone The transparent polyimide silicone resin used for the binder layer is a structural unit represented by the following general formula (1):

［式中、Ｘは炭素数４個以上の４価の有機基であって、複数個の−ＣＯ−基がＸの１つの炭素原子に結合していることはなく、Ｙは一般式（２）または一般式（３）で表されるジアミン残基

[Wherein X is a tetravalent organic group having 4 or more carbon atoms, and a plurality of —CO— groups are not bonded to one carbon atom of X, and Y is represented by the general formula (2 ) Or a diamine residue represented by the general formula (3)

（式中、Ｒ^１からＲ^６は水素原子または炭素数１から６のアルキル基であり、これらは同一でも異なっていてもよい。）

(Wherein R ¹ to R ⁶ are a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and these may be the same or different.)

（式中、Ｒ^７、Ｒ^８は水素原子または炭素数１から６のアルキル基であり、これらは同一でも異なっていてもよい。）］と一般式（４）で表される構造単位

(Wherein R ⁷ and R ⁸ are a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, which may be the same or different.)] And a structural unit represented by the general formula (4)

［式中、Ｘは炭素数４個以上の４価の有機基であって、複数個の−ＣＯ−基がＸの１つの炭素原子に結合していることはなく、Ｚは一般式（５）で表されるジアミン残基

[Wherein X is a tetravalent organic group having 4 or more carbon atoms, and a plurality of —CO— groups are not bonded to one carbon atom of X; Diamine residue represented by

（式中のＲ^９からＲ^１２は炭素数１から８の置換または非置換の一価の炭化水素基であり、これらは同一でも異なっていてもよい。また、ａは１以上１００以下の整数である。）］とを含有することを特徴とする前記に記載の発光装置である。

(In the formula, R ⁹ to R ¹² are substituted or unsubstituted monovalent hydrocarbon groups having 1 to 8 carbon atoms, and these may be the same or different. A is an integer of 1 to 100. The light-emitting device described above, wherein

  In the transparent polyimide silicone resin used for the binder layer described above, the diamine residue represented by the general formula (2) or (3) is 5 mol% or more and 95 mol% or less with respect to the total diamine residues, The diamine residue represented by the formula (5) is 5 mol% or more and 95 mol% or less, and the elastic modulus of the transparent polyimide silicone resin used for the binder layer is 0.1 MPa or more and less than 1000 MPa, and the refractive index. Is 1.45 to 1.60, and the light transmittance at a wavelength of 400 nm to 700 nm measured with a transparent polyimide silicone resin used for the binder layer as a film having a thickness of 500 μm is 70% or more, The light-emitting device described above.

  Furthermore, the first step of electrically connecting the lead electrode and the electrode of the diode chip with a conductive wire, and the diode chip is covered with a transparent polyimide silicone resin in which an additive is dispersed to form a binder layer. The present invention also includes a method of manufacturing a light emitting device including a second step and a third step of covering the diode chip and the conductive wire with a transparent resin on the binder layer.

  The transparent polyimide silicone resin of the present invention is characterized by transparency, solvent solubility, adhesion to inorganic substrates and organic resins, and low elastic modulus in addition to the heat resistance and electrical insulation properties of conventional polyimide resins. Have. Therefore, by using the transparent polyimide silicone resin of the present invention in the binder layer between the LED or laser diode chip and the sealing resin, the thermal stress generated between the chip and the sealing resin is alleviated, and the diode has excellent reliability and durability. In addition, an arbitrary color tone can be obtained by dispersing the phosphor in the binder layer.

The present invention will be described in detail below.
In the light emitting diode in one embodiment, since the thermal expansion coefficient of the transparent sealing resin is larger than that of the diode chip / substrate / lead electrode, expansion / contraction behavior due to thermal shock occurs, and desired reliability cannot be obtained. Thermal stress generated at the interface between the diode chip / substrate / lead electrode and the transparent sealing resin is suppressed by providing a highly flexible binder, improving heat resistance and durability, and fluorescent on the binder layer. An arbitrary color tone is developed by adding the body.

  The transparent polyimide silicone resin forming the binder layer used in the present invention is a reaction product of tetracarboxylic dianhydride and diamine, and the reaction product structure contains a functional group that reacts with an epoxy group. Features. For example, a carboxyl group, an amino group, a phenolic hydroxyl group and the like are generally known, but a phenol group is selected in that it does not easily react with a carboxyl group and an amino group in consideration of the production process of polyimide.

  A diamine that is a raw material of the polyimide silicone resin synthesized in the present invention will be described. As a preferred embodiment of the present invention, a diamine residue containing a phenol group is used. For example, those represented by the general formula (A) or the general formula (B) and having a diamine residue are used in the present invention.

式中、Ｒ^１からＲ^６は水素原子または炭素数１から６のアルキル基であり、これらは同一でも異なっていてもよい。上記Ｒ^１〜Ｒ^６としては、例えば、メチル基、エチル基、プロピル基、ブチル基、ペンチル基、ヘキシル基基等のアルキル基が挙げられるが、中でもメチル基が好ましい。

In the formula, R ¹ to R ⁶ are a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, which may be the same or different. Examples of R ^{1 to} R ⁶ include alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group, and among them, a methyl group is preferable.

式中、Ｒ^７、Ｒ^８は水素原子または炭素数１から６のアルキル基であり、これらは同一でも異なっていてもよい。上記Ｒ^７〜Ｒ^８としては、例えば、メチル基、エチル基、プロピル基、ブチル基、ペンチル基、ヘキシル基基等のアルキル基が挙げられるが、中でもメチル基が好ましい。

In the formula, R ⁷ and R ⁸ are a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and these may be the same or different. Examples of R ^{7 to} R ⁸ include alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group. Among them, a methyl group is preferable.

  The diamine residue containing a phenol group may be contained in an amount of 5 mol% to 95 mol% in all diamine residues, and preferably 20 mol% to 80 mol%. If the content is as low as 5 mol% or less, for example, the crosslinking density when cured with epoxy or the like is lowered, so that the curing is insufficient and the solvent resistance is lowered. Moreover, when there is much content as 95 mol% or more, content of diaminosiloxane will decrease and the solubility to an organic solvent and the adhesiveness with respect to a base material will fall.

  The present invention is characterized in that a diamine residue further containing a diaminosiloxane residue is used as a preferred embodiment. For example, what is represented by the general formula (C) is used in the present invention.

R ⁹ to R ¹² in the formula are unsubstituted or substituted monovalent hydrocarbon groups having 1 to 8 carbon atoms, such as methyl, ethyl, propyl, butyl, pentyl, and hexyl groups. Group, cycloalkyl group such as cyclopentyl group and cyclohexyl group, aryl group such as phenyl group and xylyl group, aralkyl group such as benzyl group and phenethyl group, 3,3,3-trifluoropropyl group, 3-chloropropyl group and the like In addition to trialkoxysilylated alkyl groups such as 2- (trimethoxysilyl) ethyl group, alkoxy groups such as methoxy group, ethoxy group, and propoxy group, aryloxy groups such as phenoxy group, cyano group, etc. Can be mentioned. Of these, a methyl group, an ethyl group or a phenyl group is preferred. A is an integer of 1 to 100.

  The diaminosiloxane residue may be contained in the total diamine residue in an amount of 5 mol% to 95 mol%, preferably 10 mol% to 90 mol%. By using diaminosiloxane, the solubility in an organic solvent can be improved, the elastic modulus can be lowered, and the adhesive force to the diode substrate can be improved. If the content of the diaminosiloxane residue is 5 mol% or less, the desired solvent solubility, low elastic modulus, and adhesion to the substrate are not expressed. If the content is 95 mol% or more, there are few phenol groups and curing is not possible. It becomes sufficient and the adhesiveness with the sealing resin is deteriorated.

  In these diamines, since the polyimide silicone resin of the present invention is transparent from the near ultraviolet region to the visible light region, it is preferable that the diamine as the raw material is not colored.

  As a synthetic raw material for the polyimide silicone resin of the present invention, known general diamines can be used at the same time as long as the transparency is not impaired. For example, aliphatic diamines such as tetramethylenediamine, 1,4-diaminocyclohexane and 4,4′-diaminodicyclohexylmethane, phenylenediamine, 4,4′-diaminodiphenyl ether, 2,2-bis (4-aminophenyl) propane Aromatic diamines such as these can be mentioned, and can be used alone or in combination of two or more.

  The tetracarboxylic dianhydride that is a raw material of the polyimide silicone resin synthesized in the present invention will be described. The polyimide silicone resin of the present invention is characterized in that it is transparent in the visible light region, the tetracarboxylic dianhydride as the raw material is not colored, and a charge transfer complex known as a cause of coloring Those that are difficult to form are preferred. Aliphatic tetracarboxylic dianhydrides or alicyclic tetracarboxylic dianhydrides are preferred in terms of excellent transparency, but aromatic tetracarboxylic dianhydrides that are superior in heat resistance within the range not colored may be used. Good.

  Examples of the aliphatic tetracarboxylic dianhydride include butane-1,2,3,4-tetracarboxylic dianhydride or pentane-1,2,4,5-tetracarboxylic dianhydride. Cyclic tetracarboxylic dianhydrides include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride, dicyclohexyl-3,4,3. ', 4'-tetracarboxylic dianhydride, bicyclo [2.2.1] heptane-2,3,5,6-tetracarboxylic dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic dianhydride Examples of the aromatic tetracarboxylic dianhydride include pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4. '-Gifeni Ether tetracarboxylic dianhydride, 4,4'-hexafluoro propylidene bis phthalic dianhydride, 3,3 ', and 4,4'-diphenylsulfone tetracarboxylic acid dianhydride. 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, Fragrances such as 3,3a, 4,5,9b-hexahydro-5-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione An aliphatic tetracarboxylic dianhydride having a ring may be used. These tetracarboxylic dianhydrides can be used alone or in combination of two or more.

  The polyimide silicone resin can be produced by a one-step polymerization method in which diamine and tetracarboxylic dianhydride are used in approximately equimolar numbers in the presence of a solvent and polymerized only at a high temperature, or first, an amic acid is synthesized at a low temperature. Thereafter, any of two-stage polymerization methods in which imidization is performed at a high temperature may be used.

  The ratio of the diamine component to the tetracarboxylic dianhydride component is appropriately determined according to the adjustment of the molecular weight of the polyimide silicone resin, and is usually 0.95 to 1.05, preferably 0.98 to 1.02 in molar ratio. Range. In order to adjust the molecular weight of the polyimide silicone resin, a monofunctional raw material such as phthalic anhydride or aniline can be added. In this case, the amount added is preferably 2 mol% or less with respect to the amount of the polyimide resin.

  In the case of the single-stage polymerization method, the reaction temperature is 150 to 300 ° C., and the reaction time is achieved in 1 to 15 hours. When the two-stage polymerization method is used, the polyamic acid synthesis is performed at a temperature of 0 to 120 ° C. for 1 to 100 hours, and then imidization is performed at a temperature of 0 to 300 ° C. for 1 to 15 hours.

  The solvent that can be used at the time of synthesis may be any one that is compatible with the raw material diamine, tetracarboxylic dianhydride, and the product polyimide silicone. Phenols such as phenol, 4-methoxypheno 4-methoxyphenol, 2,6-dimethylphenol, m-cresol, ethers such as tetrahydrofuran, anisole, cyclohexanone, 2-butanone, methyl isobutyl ketone, 2-heptanone, 2- Ketones such as octanone and acetophenone, esters such as butyl acetate, methyl benzoate and γ-butyrolactone, cellosolves such as butyl cellosolve acetate and propylene glycol monomethyl ether acetate, N, N-dimethylformamide, N, N-dimethylacetamide, Examples include amides such as N-methyl-2-pyrrolidone.

  Moreover, it is also possible to make it easy to remove water generated during imidization by azeotropy by using together aromatic hydrocarbons such as toluene and xylene. These solvents may be used alone or in combination of two or more.

    When using at least one of diamine and tetracarboxylic dianhydride, the reaction method is not particularly limited, for example, a method of co-condensation after mixing all the raw materials in advance, or two or more types used. There is a method of sequentially adding diamine or tetracarboxylic dianhydride while reacting individually.

  Moreover, you may use the method of imidating by adding a dehydrating agent and an imidation catalyst in an imidation process, and heating as needed. In this method, as the dehydrating agent, acid anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride can be used. The amount of the dehydrating agent used is preferably 1 to 10 mol per 1 mol of diamine.

  Moreover, as an imidation catalyst, tertiary amines, such as a pyridine, a collidine, a lutidine, a triethylamine, can be used, for example. The amount of the imidization catalyst used is preferably 0.5 to 10 mol with respect to 1 mol of the dehydrating agent to be used.

  The transparent polyimide silicone resin used in the present invention is characterized by a low elastic modulus, and the elastic modulus is 0.1 MPa or more and less than 1000 MPa, preferably 1 MPa or more and less than 600 MPa, more preferably 1 MPa or more and less than 100 MPa. If the elastic modulus is less than 0.1 MPa, the chip and the sealing resin are weakly fixed by an external force and an excessive load is applied to the chip. If the elastic modulus is greater than 1000 MPa, the diode chip, the substrate, the lead electrode, and the transparent sealing resin The role of the binder layer to relieve the thermal stress generated at the interface is not played.

  Another feature of the present invention is that the polyimide silicone resin of the present invention is transparent. The material used as the binder layer is required to transmit the light emission color of the diode without changing the color tone and without reducing the light emission intensity. This polyimide silicone resin has a UV / visible light absorption spectrum measured on a film having a thickness of 500 μm, and the transmittance in the wavelength region of 400 nm to 700 nm, that is, in the near ultraviolet region to the visible light region is 70% or more, more preferably 75% or more. It is.

  Furthermore, it is one of the characteristics that the polyimide silicone resin of the present invention has a refractive index of 1.45 to 1.60. More preferably, the refractive index is 1.47 to 1.55. The material used as the binder layer is preferably close to the refractive index of the sealing resin in order to reduce the loss of light transmission at the interface with the organic resin used for the sealing resin.

  Although the polyimide silicone resin composition of the present invention can be directly formed into a film or the like, the polyimide silicone resin of the present invention is excellent in solubility, so that it can be easily coated on various substrates with an organic solvent. It can be dissolved and adjusted to an appropriate viscosity. Solvents that can be used are not particularly limited, and may be the above-mentioned organic solvents that can be used when synthesizing generally known polyimide silicone resins, aromatic hydrocarbon solvents different from those used during synthesis, ketone solvents, etc. There is no particular limitation as long as it is soluble.

  In particular, if you want to dissolve in a low-boiling aromatic hydrocarbon solvent or ketone solvent, re-dissolve the purified polyimide resin by a method such as adding a poor solvent to the synthesized polyimide silicone resin solution and reprecipitating it. At that time, the solvent may be used for dissolution.

  Specifically, hydrocarbon solvents such as benzene, toluene, hexane and heptane, ether solvents such as tetrahydrofuran, 1,4-dioxane and diethyl ether, ketone solvents such as acetone, methyl isobutyl ketone and methyl ethyl ketone, A halogen-based solvent such as chloroform, methylene chloride, 1,2-dichloroethane can be preferably used. The solvent can also be used as a mixed solvent of two or more types.

  The amount of solvent used is preferably in the range of 0.1 to 1000 mL, more preferably in the range of 0.5 to 500 mL, and in the range of 1 to 200 mL with respect to 1 g of the polyimide silicone resin composition to be used. Is particularly preferred. If the amount used is small, the viscosity at the time of coating increases, which causes problems in workability and makes it difficult to apply uniformly. In addition, if the amount used is large, it tends to cause problems such as a burden on the environment and a required film thickness not being obtained, and it is disadvantageous in terms of cost and industrial utility value is reduced.

  The polyimide silicone resin composition of the present invention contains an additive for producing an arbitrary color tone. As such additives, conventionally known ones can be used. For example, inorganic phosphors such as yttrium, aluminum, and garnet activated by cerium that absorbs light from a light emitting element and emits longer wavelength fluorescence, Examples thereof include organic phosphors such as oxazine dyes and cyanine dyes, and colorants such as bluing agents that absorb a specific wavelength. Among them, it is more preferable to use a phosphor in view of durability and energy efficiency.

  The additive may be contained uniformly in the binder, or may be contained with a gradient in content, and may be dispersed by kneading into a binder resin using a solvent, if necessary. This additive can realize substantial wavelength conversion by setting it to 1% by mass to 50% by mass in the binder, and can realize a light emitting device having high luminance by setting it to 10% by mass to 30% by mass.

  In addition, inorganic or organic diffusion materials, metal oxides, thermally conductive fillers, anti-aging agents, radical inhibitors, UV absorbers, adhesion improvers, flame retardants, surfactants, storage stability improvers, ozone deterioration inhibitors , Light stabilizer, thickener, plasticizer, coupling agent, antioxidant, heat stabilizer, conductivity imparting agent, antistatic agent, radiation blocking agent, nucleating agent, phosphorus peroxide decomposing agent, lubricant, Pigments, metal deactivators, physical property modifiers, and the like can be added within a range that does not impair the objects and effects of the present invention.

  The transparent sealing resin used in the present invention is not particularly limited. For example, a resin used for sealing or molding of a conventional light emitting diode can be used. Specific examples include at least one selected from organic resins such as epoxy resin, polycarbonate resin, urethane resin, polyimide resin, silicone resin, and acrylic resin, but are not limited thereto. Among these, a transparent epoxy resin is preferable from the viewpoint of high transparency and durability and excellent practical properties such as adhesion to the binder layer.

  Examples of the transparent epoxy resin include bisphenol A diglycidyl ether, 2,2′-bis (4-glycidyloxycyclohexyl) propane, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and vinylcyclohexene dioxide. 2- (3,4-epoxycyclohexyl) -5,5-spiro- (3,4-epoxycyclohexane) -1,3-dioxane, bis (3,4-epoxycyclohexyl) adipate, 1,2-cyclopropane Aliphatic acid anhydrides such as hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, trialkyltetrahydrophthalic anhydride, hydrogenated methylnadic acid anhydride, and epoxy resins such as dicarboxylic acid bisglycidyl ester and triglycidyl isocyanurate Which is cured and the like.

  Among these, bisphenol A diglycidyl ether, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, from the viewpoint of better properties as a sealing material for light emitting diodes such as transparency, Those in which triglycidyl isocyanurate and the like are cured with methylhexahydrophthalic anhydride are preferable, and those in which 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate is cured with methylhexahydrophthalic anhydride are more preferable. .

  The adhesive property which was excellent in the interface of a binder layer and sealing resin is obtained by thermosetting the said transparent epoxy resin on the polyimide silicone resin of this invention.

  Curing conditions are not particularly limited, but curing is performed in the range of 80 ° C. to 300 ° C., preferably 100 ° C. to 250 ° C. When it is cured at 80 ° C. or less, it takes too much time for heat curing, and it is not practical. When it is cured at 300 ° C. or more, the substrate and the sealing resin are thermally deteriorated.

  The diode chip used in the present invention is not particularly limited, and a diode chip used in a conventionally known light emitting diode can be used. Such a diode chip is produced by laminating a semiconductor material on a substrate provided with a buffer layer of GaN, AlN or the like, if necessary, by various methods such as MOCVD, HDVPE, and liquid phase growth. Things. Various materials can be used as the substrate in this case, and examples thereof include sapphire, spinel, SiC, Si, ZnO, and GaN single crystal.

  Examples of laminated semiconductor materials include GaAs, GaP, GaAlAs, GaAsP, AlGaInP, GaN, InN, AlN, InGaN, InGaAlN, and SiC.

  Various light emission wavelengths of the diode chip from the ultraviolet region to the infrared region can be used, but the effect of the present invention is particularly remarkable when the main light emission peak wavelength is 405 to 800 nm. A single diode chip may be used, or a plurality of diode chips may be used to emit light.

  The electrodes on the diode chip can be electrically connected to the lead terminals and the like by various methods. Examples of the electrical connection member include a bonding wire using gold, silver, copper, platinum, aluminum, or an alloy thereof. Alternatively, a conductive adhesive or the like in which a conductive filler such as silver or carbon is filled with a resin can be used. Among these, from the viewpoint of workability and cost, it is preferable to use a conductive wire made of aluminum or the like.

  The light emitting device of the present invention can be manufactured by covering the light emitting diode with the binder layer (first resin) and the transparent resin layer (second resin) as described above. The light-emitting element is not limited to being directly sealed, but includes cases where it is indirectly covered.

  As a coating method, for example, a diode chip is coated with the first resin of the present invention, and then molded by a normal method using the second resin of the present invention. After molding with a normal method using the above resin, and further molding with a normal method using the second resin of the present invention, a cup around the diode chip, for example, a diode chip placed in the lower part After sealing the cavity, the package recess, etc. with the first resin of the present invention, the mold is further molded by the usual method using the second resin of the present invention. Examples of the method include a method of coating the periphery of the resin with a second resin of the present invention after molding with a normal method using the resin. In this case, from the viewpoint that the light resistance durability of the second resin of the present invention is good, the first optical path length of the light emitted from the diode chip in the second resin can be increased. It is preferable to coat so that the average optical path length in the resin becomes shorter.

  The light emitting device of the present invention can be used for various known applications. Specifically, for example, a backlight, illumination, sensor light source, vehicle instrument light source, signal lamp, indicator lamp, display device, planar light source, display, decoration, various lights, and the like can be given.

  Although the synthesis example of the transparent polyimide silicone resin which can be used as a binder layer is shown below and the aspect of the light-emitting device using this is shown in an Example, this invention is not limited to these.

Synthesis Example 1 (Synthesis of imide silicone resin)
1,3,3a, 4,5,9b-Hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,1,3,3a, 4,5,9b in a flask equipped with a stirrer, thermometer and nitrogen displacement apparatus. 2-c] 30.0 g (0.1 mol) of furan-1,3-dione and 250 g of N, N-dimethylacetamide were charged and dissolved by stirring. Next, 17.3 g (0.035 mol) of 2,2 ′-{2-hydroxy-3- (3,5-methyl-4-amino) -benzyl-5-methyl} -diphenylmethane was added into the flask. The temperature of the reaction system was maintained at 50 ° C. for 3 hours. Furthermore, 56.2 g (0.065 mol) of diaminosiloxane represented by the following formula was added dropwise at room temperature, and the mixture was stirred at room temperature for 12 hours after the completion of the dropwise addition.

  Next, after attaching a reflux condenser with a moisture receiver to the flask, 50 g of toluene was added, the temperature was raised to 170 ° C. and the temperature was maintained for 6 hours, and an almost transparent solution was obtained.

  The obtained solution was poured into methanol as a poor solvent to reprecipitate the resin. The result of measuring the infrared absorption spectrum of this resin is shown in FIG. Absorption based on polyamic acid indicating the presence of unreacted functional groups did not appear, and absorption based on imide groups was confirmed at 1780 cm −1 and 1720 cm −1. The obtained resin has a repeating unit represented by the formula (7).

  Where X is

  Y is

  Z is

  Moreover, it was 11000 when the weight average molecular weight (polystyrene conversion) of this resin was measured by the gel permeation chromatography (GPC) which uses tetrahydrofuran as a solvent. This resin was dissolved in methyl isobutyl ketone, coated on a glass substrate and dried to form a film having a thickness of 600 μm. The light transmittance of this film was measured and the result is shown in FIG. The light transmittance from a wavelength of 400 nm to 700 nm was 70% or more. The elastic modulus was 600 MPa and the refractive index was 1.505.

Synthesis Example 2 (Synthesis of imide silicone resin)
1,3,3a, 4,5,9b-Hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,1,3,3a, 4,5,9b in a flask equipped with a stirrer, thermometer and nitrogen displacement apparatus. 2-c] furan-1,3-dione (30.0 g, 0.1 mol) and N, N-dimethylacetamide (250 g) were charged. Subsequently, 34.6 g (0.07 mol) of 2,2 ′-{2-hydroxy-3- (3,5-methyl-4-amino) -benzyl-5-methyl} -diphenylmethane was added to the flask. The temperature of the reaction system was maintained at 50 ° C. for 3 hours. Furthermore, 26.0 g (0.03 mol) of diaminosiloxane represented by the following formula was added dropwise at room temperature, and the mixture was stirred at room temperature for 12 hours after completion of the addition.

  Next, after attaching a reflux condenser with a moisture receiver to the flask, 50 g of toluene was added, the temperature was raised to 170 ° C. and the temperature was maintained for 6 hours, and an almost transparent solution was obtained.

  The obtained solution was poured into methanol as a poor solvent to reprecipitate the resin. When the infrared absorption spectrum of this resin was measured, absorption based on polyamic acid indicating that there was an unreacted functional group did not appear, and absorption based on imide groups was confirmed at 1780 cm −1 and 1720 cm −1. The obtained resin has a repeating unit represented by Formula (8).

Where X is

Y is

Z is

  Moreover, it was 7000 when the weight average molecular weight (polystyrene conversion) of this resin was measured by the gel permeation chromatography (GPC) which uses tetrahydrofuran as a solvent. This resin was dissolved in methyl isobutyl ketone, coated on a glass substrate and dried to form a film having a thickness of 700 μm. When the light transmittance of this film was measured, the light transmittance from a wavelength of 400 nm to 700 nm was 70% or more. The elastic modulus was 200 MPa and the refractive index was 1.510.

Synthesis Example 3 (Synthesis of imide silicone resin)
In a flask equipped with a stirrer, thermometer and nitrogen displacement apparatus, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1, 2-c] 30.0 g (0.1 mol) of furan-1,3-dione, 250 g of N, N-dimethylacetamide, and 100 g of toluene were charged. Subsequently, 12.35 g (0.025 mol) of 2,2 ′-{2-hydroxy-3- (3,5-methyl-4-amino) -benzyl-5-methyl} -diphenylmethane was added into the flask. The temperature of the reaction system was maintained at 50 ° C. for 3 hours. Furthermore, 64.88 g (0.075 mol) of diaminosiloxane represented by the following formula was added dropwise at room temperature, and the mixture was stirred at room temperature for 12 hours after the completion of the addition.

  Next, after attaching a reflux condenser with a moisture receiver to the flask, 20.4 g of acetic anhydride and 26.4 g of pyridine were added, the temperature was raised to 50 ° C., and the temperature was maintained for 3 hours.

  The obtained solution was poured into methanol as a poor solvent to reprecipitate the resin. When the infrared absorption spectrum of this resin was measured, absorption based on polyamic acid indicating that there was an unreacted functional group did not appear, and absorption based on imide groups was confirmed at 1780 cm −1 and 1720 cm −1. The obtained resin has a repeating unit represented by the formula (9).

  Where X is

  Y is

  Z is

  Moreover, it was 24000 when the weight average molecular weight (polystyrene conversion) of this resin was measured by the gel permeation chromatography (GPC) which uses tetrahydrofuran as a solvent. This resin was dissolved in methyl isobutyl ketone, applied onto a glass substrate and dried to form a film having a thickness of 650 μm. When the light transmittance of this film was measured, the light transmittance from a wavelength of 400 nm to 700 nm was 70% or more. The elastic modulus was 50 MPa and the refractive index was 1.522.

Synthesis Example 4 (Synthesis of imide silicone resin)
In a flask equipped with a stirrer, a thermometer, and a nitrogen displacement device, 44.4 g (0.1 mol) of 4,4′-hexafluoropropylidenebisphthalic dianhydride and 184 g of cyclohexanone were charged and dissolved by stirring. . Next, 8.2 g (0.02 mol) of 2,2-bis [4- (4-aminophenoxy) phenyl] propane was added into the flask, and the temperature of the reaction system was maintained at 50 ° C. for 3 hours. Furthermore, 70.3 g (0.08 mol) of diaminosiloxane represented by the following formula was added dropwise at room temperature, and the mixture was stirred at room temperature for 12 hours after the completion of the addition.

  Next, after attaching a reflux condenser with a moisture receiver to the flask, 50 g of toluene was added, the temperature was raised to 145 ° C. and the temperature was maintained for 6 hours, and an almost transparent solution was obtained.

  The obtained solution was poured into methanol as a poor solvent to reprecipitate the resin. When the infrared absorption spectrum of this resin was measured, absorption based on polyamic acid indicating that there was an unreacted functional group did not appear, and absorption based on imide groups was confirmed at 1780 cm −1 and 1720 cm −1. The obtained resin has a repeating unit represented by the formula (10).

  Where X is

  And Y is

  And Z is

  Moreover, it was 100000 when the weight average molecular weight (polystyrene conversion) of this resin was measured by the gel permeation chromatography (GPC) which uses tetrahydrofuran as a solvent. This resin was dissolved in methyl isobutyl ketone, coated on a glass substrate and dried to form a film having a thickness of 60 μm. Of the light transmittance from a wavelength of 400 nm to 700 nm, it was 70% or less from 400 nm to 480 nm. The elastic modulus was 10 MPa and the refractive index was 1.441.

Example 1 (Method for Manufacturing Light-Emitting Device)
Although the example of the light-emitting device which uses the transparent polyimide silicone resin synthesize | combined in the said synthesis examples 1-3 for the buffer layer is shown and demonstrated to a drawing, the aspect of the light-emitting device of this invention is not restrict | limited to this.

  FIG. 3 shows a sectional view of an example of a light emitting device to which the transparent polyimide silicone resin of the present invention is applied. A heat-resistant resin that can be insert-molded is used for the substrate 1 to constitute the light-emitting device 7 that covers the diode chip 2. A lead internal electrode 3b is provided as a conducting portion for electrically connecting the diode chip 2 and the outside to the substrate as a support. The lead electrode includes an external electrode 3a and an internal electrode 3b. The lead electrodes 3a and 3b are made of Ag-plated copper electrodes so as not to impair the light extraction efficiency. The diode chip 2 is fixedly locked by die bonding. Thereafter, the electrode provided on the diode chip 2 and the electrode of the substrate are wire-bonded by the conducting wire 4. Furthermore, a binder layer 5 made of a dispersed polyimide silicone resin containing 20% by mass of the phosphor of the present invention is formed in the concave portion of the substrate, and a transparent epoxy resin 6 is injected and thermally cured to be a surface mount type light emitting device. 7 is formed.

Example 2
A varnish obtained by dissolving the transparent polyimide silicone resin synthesized in Synthesis Example 1 in methyl isobutyl ketone is applied on an aluminum plate, and the solvent is volatilized by air drying to form a film having a film thickness of 100 μm. 100 parts of epoxy resin ERL4221 (trade name, manufactured by UCC), 100 parts of alicyclic acid anhydride Rikazide MH-700 (trade name, manufactured by Shin Nippon Chemical Co., Ltd.), and 10 parts of sodium salt DY065 (trade name, manufactured by Ciba Geigy) The resin composition was applied at a thickness of 1 mm and cured at 150 ° C. for 5 hours. The refractive index of this sealing epoxy resin was 1.494. The test piece was subjected to an environmental test for 169 hours under a saturated water vapor pressure of 121 ° C. and 2.1 atm. No appearance abnormality such as interfacial peeling was observed.

Example 3
A varnish obtained by dissolving the transparent polyimide silicone resin synthesized in Synthesis Example 2 in methyl isobutyl ketone was applied on an aluminum plate, and the solvent was volatilized by air drying to form a film having a thickness of 100 μm. Further, 100 parts of ERL4221 was formed thereon. A resin composition consisting of 100 parts of Rikazid MH-700 and 10 parts of DY065 was applied at a thickness of 1 mm and cured at 150 ° C. for 5 hours. This test piece was subjected to an environmental test for 169 hours under a saturated water vapor pressure of 121 ° C. and 2.1 atm. No appearance abnormality such as interfacial peeling was observed.

Example 4
A varnish obtained by dissolving the transparent polyimide silicone resin synthesized in Synthesis Example 3 in methyl isobutyl ketone was applied on an aluminum plate, and the solvent was evaporated by air drying to form a film having a thickness of 100 μm. Further, 100 parts of ERL4221 was formed thereon. A resin composition consisting of 100 parts of Rikazid MH-700 and 10 parts of DY065 was applied at a thickness of 1 mm and cured at 150 ° C. for 5 hours. This test piece was subjected to an environmental test for 169 hours under a saturated water vapor pressure of 121 ° C. and 2.1 atm. No appearance abnormality such as interfacial peeling was observed.

Comparative Example 1
A varnish obtained by dissolving the transparent polyimide silicone resin synthesized in Synthesis Example 4 in methyl isobutyl ketone was applied on an aluminum plate, and the solvent was evaporated by air drying to form a film having a thickness of 100 μm. Further, 100 parts of ERL4221 was formed thereon. A resin composition consisting of 100 parts of Rikazid MH-700 and 10 parts of DY065 was applied at a thickness of 1 mm and cured at 150 ° C. for 5 hours. The test piece was subjected to an environmental test for 169 hours under a saturated water vapor pressure of 121 ° C. and 2.1 atm. As a result, whitening was observed at the interface.

  The results of environmental tests are summarized below.

2 is an infrared absorption spectrum diagram of the polyimide silicone resin synthesized in Synthesis Example 1. FIG. 2 is a transmittance spectrum diagram of the polyimide silicone resin synthesized in Synthesis Example 1. FIG. It is sectional drawing which shows typically the principal part structure of the light-emitting device concerning embodiment of this invention.

Explanation of symbols

1 Substrate 2 Diode chip 3a Lead electrode (external electrode)
3b Lead electrode (internal electrode)
4 Conductive wire 5 Binder layer 6 Transparent resin layer 7 Light emitting device

Claims (9)

  A light emitting diode (LED) or a laser diode, the diode being a diode chip, a conductive wire for electrically connecting the lead electrode and the electrode of the diode chip, a binder layer covering the diode chip, and a binder layer A light emitting device comprising: a transparent resin layer covering the diode chip and the conductive wire, wherein the binder layer contains a transparent polyimide silicone resin and an additive for changing a color tone. A structural unit in which the transparent polyimide silicone resin used in the binder layer is represented by the general formula (1)

[Wherein X is a tetravalent organic group having 4 or more carbon atoms, and a plurality of —CO— groups are not bonded to one carbon atom of X, and Y is represented by the general formula (2 ) Or a diamine residue represented by the general formula (3)

(Wherein R ¹ to R ⁶ are a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and these may be the same or different.)

(Wherein R ⁷ and R ⁸ are a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, which may be the same or different.)] And a structural unit represented by the general formula (4)

[Wherein X is a tetravalent organic group having 4 or more carbon atoms, and a plurality of —CO— groups are not bonded to one carbon atom of X; Diamine residue represented by

(Wherein R ⁹ to R ¹² are substituted or unsubstituted monovalent hydrocarbon groups having 1 to 8 carbon atoms, and these may be the same or different. A is an integer of 1 to 100. The light-emitting device according to claim 1, further comprising:   In the transparent polyimide silicone resin used for the binder layer, the diamine residue represented by the general formula (2) or (3) is 5 mol% or more and 95 mol% or less with respect to all diamine residues, and the general formula The light emitting device according to claim 2, wherein the diamine residue represented by (5) is 5 mol% or more and 95 mol% or less.   The elastic modulus of the transparent polyimide silicone resin used for the binder layer is 0.1 MPa or more and less than 1000 MPa, and contains a functional group that reacts with an epoxy group. The light-emitting device of description.   The light-emitting device according to any one of claims 1 to 4, wherein the transparent polyimide silicone resin used for the binder layer has a refractive index of 1.45 to 1.60.   6. The light transmittance at a wavelength of 400 nm to 700 nm measured by using a transparent polyimide silicone resin used for the binder layer as a film having a thickness of 500 [mu] m is 70% or more. The light emitting device according to item.   The light-emitting device according to claim 1, wherein the transparent resin layer is an epoxy resin.   The light-emitting device according to any one of claims 1 to 7, wherein the additive for changing the color tone contained in the binder layer is a phosphor.   A first step of electrically connecting the lead electrode and the electrode of the diode chip by a conductive wire; a second step of forming a binder layer by covering the diode chip with a transparent polyimide silicone resin containing a phosphor; A method for manufacturing a light emitting device according to any one of claims 1 to 8, further comprising a third step of covering the diode chip and the conductive wire with a transparent resin on the binder layer.

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