JP2008159756A - Manufacturing method of white light-emitting diode, and photo-curing phosphor containing composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a white light-emitting diode which has less chromatic irregularity. <P>SOLUTION: The manufacturing method of a white light-emitting diode has a process wherein a photo-curing phosphor containing composition which includes a photo-polymerizing compound, a photo-polymerization initiator, and a phosphor is used to form a photo-curing phosphor containing composition layer on the luminous surface of a light emitting diode chip; a process wherein the light generated by light-emitting the light emitting diode chip is utilized to cure the photo-curing phosphor containing composition, and further; and a process wherein the uncured substance is so removed as to leave the cured substance of the photo-curing phosphor containing composition. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a white light emitting diode capable of obtaining white light and a photocurable phosphor-containing composition used for producing the white light emitting diode, and more specifically, on the surface of the light emitting diode chip, The present invention relates to a method for producing a white light-emitting diode capable of obtaining white light emission by forming a phosphor-containing composition layer, and a photocurable phosphor-containing composition used for producing the white light-emitting diode.

  In recent years, white light-emitting diodes (hereinafter, the issuing diode is abbreviated as LED) have attracted attention. As a configuration for obtaining white light using an LED, various combinations of an LED and a phosphor that emits fluorescence in response to light emitted from the LED have been proposed. For example, an LED that emits ultraviolet light, a phosphor that excites three primary color phosphors by the ultraviolet light emitted from the LED, and obtains white light by fluorescence from the phosphors of the three primary colors, a blue LED, and green and red phosphors A combination configuration, a combination of a blue LED and a yellow non-fluorescent substance has been proposed.

Further, Patent Document 1 or 2 below discloses a white LED formed by sealing a blue LED with a sealing material in which a compound that emits orange fluorescence is dispersed.
JP 2003-204085 A JP 2003-204082 A

  However, as described in Patent Document 1, in a structure in which, for example, a blue LED is sealed using a sealing material in which a phosphor is dispersed, uneven color and uneven light emission tend to occur due to the dispersion state of the phosphor. there were.

  An object of the present invention is to provide a white LED capable of sufficiently suppressing color unevenness and light emission unevenness in view of the above-described current state of the prior art, and to be used in the manufacturing method. An object of the present invention is to provide a photocurable phosphor-containing composition.

  A method for producing a white LED according to the present invention uses a photocurable phosphor-containing composition containing a photopolymerizable compound, a photopolymerization initiator, and a phosphor, and a photocurable phosphor on the light emitting surface of the LED chip. A step of forming a composition layer, a step of causing the LED chip to emit light, curing the photocurable phosphor-containing composition layer using the generated light, and the photocurability after the curing step. And a step of removing an uncured product of the photocurable phosphor-containing composition so as to leave a cured product of the phosphor-containing composition.

  In the method for producing a white LED according to the present invention, preferably, after the uncured product of the photocurable phosphor-containing composition is removed, the photocurable phosphor provided on the light emitting surface of the LED chip and the LED chip. The process of sealing the hardened | cured material of a containing composition with a sealing material is further provided. In this case, since the cured product of the LED chip and the photocurable phosphor-containing composition is sealed by the sealing material, a white LED having excellent reliability can be obtained. In particular, after removing the uncured product of the photocurable phosphor-containing composition, the surface of the cured product of the photocurable phosphor-containing composition tends to have irregularities. By sealing the surface of the white LED, the surface of the white LED can be smoothed, thereby making it possible to further reduce the unevenness of light emission and improve the reliability and environmental resistance of the white LED.

  The photocurable phosphor-containing composition according to the present invention is a photocurable phosphor-containing composition used in the method for producing a white LED of the present invention, and includes a photopolymerizable compound, a photopolymerization initiator, and a phosphor. It is characterized by including.

  Preferably, the photopolymerizable compound is a photocationic polymerizable compound and / or a photoradical polymerizable compound, and is cured by photocationic polymerization and / or photoradical polymerization, so that light generated by light emission of the diode chip is used. Thus, the photocurable phosphor-containing composition can be quickly cured. More preferably, a photocurable epoxy resin is used as the photopolymerizable compound, and in that case, the translucency and mechanical strength of the cured product of the photocurable phosphor-containing composition are sufficiently increased, and further, It is possible to provide a white LED that hardly causes uneven color and uneven light emission and has excellent mechanical reliability.

  In addition, the phosphor used in the photocurable phosphor-containing composition according to the present invention is not particularly limited. Preferably, the phosphor and the light emitted from the LED chip are excited by the light emitted from the LED chip. It is at least one kind of phosphor that enables white light to be generated by the fluorescence emitted by the body. In this case, white light with little color unevenness and light emission unevenness can be obtained according to the present invention by the combination of LED and fluorescence.

  Details of the present invention will be described below.

  As a result of studying the problem of uneven color and uneven light emission in the conventional white LED as described in Patent Document 1, the present inventors have found light emission due to the uneven distribution of the phosphors dispersed in the sealing material. We found that high density parts and low density parts were mixed, resulting in uneven color and uneven light emission. Accordingly, as a result of various studies to reduce the color unevenness and light emission unevenness, the inventors of the present application have found that light emitted from the light emitting portion of the LED chip in an arbitrary direction in a configuration in which the LED chip is covered with the phosphor layer. As a central axis, a cylinder having an arbitrary cross-sectional area and an inner side surface and an outer side surface of the phosphor layer as both end surfaces is assumed, and the number of phosphors per volume in the cylinder is arbitrary. If it is substantially the same in each cylinder having a light beam as a central axis, it is considered that color unevenness, light emission unevenness and the like can be significantly reduced, and the present invention has been made.

  That is, in the method for producing a white LED of the present invention, after the photocurable phosphor-containing composition layer is formed on the light emitting surface of the LED chip, the LED chip is caused to emit light, and the generated light is used to generate the photocurable fluorescence. The body-containing composition is cured, but after the curing step, the uncured product of the photocurable phosphor-containing composition is removed so as to leave a cured product of the photocurable phosphor-containing composition. By removing this uncured product, the difference in the number of phosphors is reduced among a large number of cylinders having the above-mentioned arbitrary light beam as the central axis. This is due to the following reason.

  In preparing the photocurable phosphor-containing composition, the composition is sufficiently kneaded so that the phosphor distribution is uniform. However, even in that case, the phosphor distribution must be uneven. Therefore, at the stage where the photocurable phosphor-containing composition layer is formed on the light emitting surface of the LED chip, the phosphor is not necessarily uniformly dispersed.

  In the present invention, the LED chip emits light, and the photocurable phosphor-containing composition layer is cured using the generated light, but the light linearly travels outward from the light emitting surface of the LED chip. When phosphor particles are present in this light path, that is, in the optical path, light is absorbed by the phosphor particles and fluorescence is emitted. It is assumed that the phosphor particles are present in a biased manner in this path-shaped optical path, that is, in the cylinder having the light beam as the central axis. In this case, the light emitted from the LED collides with many phosphor particles in a portion where many phosphor particles are present, and the amount of light used for the curing reaction is relatively small in the outer portion than the phosphor particles. Become. As a result, curing proceeds mainly in the range from the LED chip to the portion where the phosphor particles are present. On the other hand, in a portion where the phosphor particles are few, light proceeds to a portion further away from the light emitting diode chip, and curing proceeds.

  Therefore, when the uncured product is removed, a concave portion is formed on the surface of the cured product of the photocurable phosphor-containing composition by removing the uncured product. The difference in the number of particles is reduced. Thereby, uneven color and uneven light emission are remarkably suppressed.

  In other words, when a large amount of phosphor particles are present in a certain optical path, the curing of the photocurable phosphor-containing composition does not proceed at a portion farther than the portion where the phosphor particles are present. Since it becomes hardened | cured material, the fluorescent substance particle to the part in which many fluorescent substance particles exist is used in this optical path. On the other hand, in an optical path with a small number of phosphor particles, light travels farther and curing proceeds. Accordingly, the amount of uncured material to be removed is reduced, but a thicker cured material layer is formed, and the number of phosphor particles in the optical path is the optical path in which the number of phosphor particles described above is large. Will approach the number of phosphor particles.

  Hereinafter, details of the production method of the present invention will be described more specifically.

(Photocurable phosphor-containing composition)
In the present invention, a photocurable phosphor-containing composition containing a photopolymerizable compound, a photopolymerization initiator, and a phosphor is used.

  It does not specifically limit as said photopolymerizable compound, A photocationic polymerizable compound, a radical photopolymerizable compound, a photobase polymerizable compound, etc. can be used.

  The photocationically polymerizable compound is not particularly limited as long as it has at least one photocationically polymerizable functional group in the molecule. For example, at least one epoxy group, oxetanyl group, hydroxyl group in the molecule , Vinyl ether groups, episulfide groups, ethyleneimine groups, compounds having hydrolyzable silyl groups represented by alkoxysilyl groups, and the like. In particular, photo-curing epoxy resin (hereinafter referred to as epoxy compound), which is a compound having at least one epoxy group in the molecule, has high photocationic polymerizability and photocuring proceeds efficiently even with a small amount of light. Or a compound having at least one oxetanyl group in the molecule (hereinafter also referred to as oxetanyl compound) is preferably used.

  The property (molecular weight) of these photocationically polymerizable compounds is not particularly limited and may be any of a monomer, an oligomer and a polymer. Moreover, these photocationic polymerizable compounds may be used independently and 2 or more types may be used together.

  The epoxy compound is not particularly limited. For example, bisphenol type epoxy resins such as bisphenol A type epoxy resin and bisphenol F type epoxy resin; novolak type epoxy resins such as phenol novolak type epoxy resin and cresol novolak type epoxy resin; Group epoxy resin, alicyclic epoxy resin, heterocyclic epoxy resin, polyfunctional epoxy resin, biphenyl type epoxy resin, glycidyl ether type epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin; hydrogenated bisphenol A Type epoxy resins and other alcohol type epoxy resins; brominated epoxy resins and other halogenated epoxy resins; rubber-modified epoxy resins, urethane-modified epoxy resins, epoxidized polybutadiene, and epoxidized styrene resins Diene - styrene block copolymer, epoxy group-containing polyester resin, epoxy group-containing polyurethane resins, epoxy group-containing acrylic resins. These epoxy compounds may be used alone or in combination of two or more.

  Examples of commercially available epoxy compounds include “Epicoat” series such as “Epicoat 806”, “Epicoat 828”, “Epicoat 1001”, and “Epicoat 1002” manufactured by Japan Epoxy Resin Co., Ltd. And “Celoxide” series such as “Celoxide 2021” manufactured by Daicel Chemical Industries, Ltd.

  The oxetanyl compound is not particularly limited, and examples thereof include phenoxymethyl oxetane, 3,3-bis (methoxymethyl) oxetane, 3,3-bis (phenoxymethyl) oxetane, and 3-ethyl-3- (phenoxymethyl) oxetane. , 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, 3-ethyl-3-{[3- (triethoxysilyl) propoxy] methyl} oxetane, di [1-ethyl (3-oxetanyl)] methyl And ether, oxetanylsilsesquioxane, phenol novolac oxetane, 1,4-bis {[(3-ethyl-3-oxetanyl) methoxy] methyl} benzene, and the like. These oxetanyl compounds may be used alone or in combination of two or more.

  Examples of the photo-cationic polymerizable compound other than the epoxy compound and the oxetanyl compound include, for example, epoxides, cyclic ethers, vinyl ethers, vinylamines, unsaturated hydrocarbons, lactones and other cyclic esters, and lactams. , At least one photocationically polymerizable group such as cyclic carbonates, cyclic acetals, aldehydes, cyclic amines, cyclic sulfides, cyclosiloxanes, cyclotriphosphazenes and other photocationically polymerizable groups and monomers And a photocationically polymerizable compound. Among these, cyclic ether monomers such as epoxide monomers and vinyl organic monomers are preferably used.

  Although it does not specifically limit as said radical photopolymerizable compound, The appropriate radical polymerizable compound which has polymerizable unsaturated groups, such as a vinyl bond, can be mentioned. Examples of such radical polymerizable compounds include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, epoxy acrylate, urethane acrylate, polyester acrylate, and polyether acrylate. (Meth) acrylates such as unsaturated polyester, styrene compounds, and the like. Moreover, you may copolymerize the compound which has an unsaturated bond copolymerizable with these compounds. Examples of such compounds include styrene derivatives, vinyl ester derivatives, N-vinyl derivatives, (meth) acrylate derivatives, (meth) acrylic acid, and the like.

  Further, the compound having a hydrolyzable silyl group is not particularly limited, but tetramethoxysilane, tetraethoxysilane, trimethoxymethylsilane, triethoxymethylsilane, dimethoxydimethylsilane, diethoxydimethylsilane, trimethoxyethylsilane. , Triethoxyethylsilane, and the like, and partial condensates thereof may be used. Further, a resin having two or more trimethoxysilyl groups or triethoxysilyl groups and hydrolyzable silyl groups in one molecule may be used. Examples of the resin having a hydrolyzable silyl group include polypropylene glycol, polyalkyl (meth) acrylate, polyester, polyurethane, and polyolefin. Commercially available MS polymers S-203, S-303, S-903, etc., Silyl SAT-200, MA-403, MA-447 (manufactured by Kaneka), Exester ESS-2410, ESS-2420, ESS-3630 (Asahi Glass) May be used.

  Examples of the basic polymerizable compound include a compound having at least one epoxy group in the molecule, a compound having an isocyanate group, and a compound having a (meth) acryloyl group. As the compound having an epoxy group or a (meth) acryloyl group, the compounds described above can be used. Examples of the compound having an isocyanate group include diphenylmethane diisocyanate (MDI), toluylene diisocyanate (TDI), naphthylene-1,5-diisocyanate, o-toluylene diisocyanate, triphenylmethane triisocyanate, tris (p-isocyanatephenyl) thio. Monomers such as phosphite, polymethylene polyphenyl isocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate (XDI), or isocyanurate-modified, urethane-modified, biuret-modified, carbodiimide Modified body, allophanate modified body, trimethylolpropane adduct, blocked isocyanate, etc.

  In the present invention, both the radical photopolymerizable compound and the cationic photopolymerizable compound may be used in combination as the photopolymerizable compound. In that case, since the wavelength of the light emitted from the LED chip is constant, a photocationic polymerization initiator and a radical photopolymerization initiator described later that are excited by the light emitted from the LED chip may be used.

(Photopolymerization initiator)
The photopolymerization initiator is not particularly limited and can be appropriately selected according to the photopolymerizable compound. When using a photocationic polymerizable compound, a photocationic polymerization initiator is used. When using a photoradical polymerizable compound, a photoradical polymerization initiator is used. When using a polymerizable compound having a hydrolyzable silyl group, light is used. Cationic polymerization initiators and α, α-diacyl compounds can be used.

  The cationic photopolymerization initiator may be of an ionic photoacid generation type or a nonionic photoacid generation type, and is not particularly limited. Examples of the photocationic polymerization initiator include onium salts such as aromatic diazonium salts, aromatic halonium salts, and aromatic sulfonium salts; organometallic complexes such as iron-allene complexes, titanocene complexes, and arylsilanol-aluminum complexes. Examples of the nonionic photoacid generation type photocationic polymerization initiator include nitrobenzyl ester, sulfonic acid derivative, phosphoric acid ester, phenolsulfonic acid ester, diazonaphthoquinone, N-hydroxyimidosulfonate and the like. .

  Among them, a photocationic polymerization initiator comprising a boronate having a boronic acid as a counter anion as represented by the following formula (1) is preferably used because of high polymerization efficiency. Specifically, “Photoinitiator” And a commercial product such as “2074” (manufactured by Rhodia).

  Furthermore, it is preferable that the ionic photoacid generating type photocationic polymerization initiator has a sulfonium cation moiety represented by the following general formula (2) or the following general formula (3). The use of a photocationic polymerization initiator having a sulfonium cation moiety as described below is preferred because the cured product is less colored and is excellent in weather resistance transparency.

In the general formula (2) and the general formula (3), R ^{9 to} R ¹⁴ may be the same as or different from each other, and each represents a monovalent or divalent phenyl group or naphthyl group. These phenyl groups or naphthyl groups are linear or branched C ₁ -C ₁₂ alkyl groups, linear or branched C ₁ -C ₁₂ alkoxyl groups, halogen atoms, —OH groups, —COOH. (wherein the alkyl moiety is linear or branched C ₁ -C ₁₂ residues) groups and -COO- alkyl ester group is optionally substituted with at least one group selected from the group consisting of It may be.

  The radical photopolymerization initiator is not particularly limited. Examples of the radical photopolymerization initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, α-hydroxy-α, acetophenone derivative compounds such as α′-dimethylacetophenone, methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone; benzoin ether compounds such as benzoin ethyl ether and benzoin propyl ether; ketal derivative compounds such as benzyldimethyl ketal; Ketone; acyl phosphine oxide; acyl phosphonate; 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-N, N-dimethylamino- 1- (4-morpholine Phenyl) -1-butanone; 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis- (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide; bis (n5-cyclopenta) Dienyl) -bis (pentafluorophenyl) -titanium, bis (n5-cyclopentadienyl) -bis [2,6-difluoro-3- (1H-pyridyl-1-yl) phenyl] -titanium, etc. Can do.

  Only one type of radical polymerization initiator may be used, or a plurality of types may be used in combination. Of these, acylphosphine oxide and the like are preferably used since absorption for the emission wavelength of the LED after photolysis is eliminated. Examples of commercially available acylphosphine oxides include bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide and bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide. Can be mentioned.

  Although it does not specifically limit as an alpha-diacyl compound etc. which are utilized for the polymeric compound which has the said hydrolysable silyl group, As described in WO2002 / 083764, for example, an acid anhydride, a thiocarboxylic acid anhydride, etc. , Α, α-diketone, maleimide, phenylphosphine oxide, and the like. More specifically, as the acid anhydride, acetic anhydride, propionic anhydride, butyric anhydride, isobutyric anhydride, valeric anhydride, 2-methylbutyric anhydride, trimethylacetic anhydride, hexanoic anhydride , Heptanoic acid anhydride, decanoic acid anhydride, lauric acid anhydride, myristic acid anhydride, palmitic acid anhydride, stearyl acid anhydride, docosanoic acid anhydride, crotonic acid anhydride, acrylic acid anhydride, methacrylic acid anhydride , Oleic anhydride, linolenic anhydride, chloroacetic anhydride, iodoacetic anhydride, dichloroacetic anhydride, trifluoroacetic anhydride, chlorodifluoroacetic anhydride, trichloroacetic anhydride, pentafluoropropionic anhydride , Heptafluorobutyric anhydride, succinic anhydride, methyl succinic anhydride, 2,2-dimethylsuccinic acid Anhydride, isobutyl succinic anhydride, 1,2-cyclohexanedicarboxylic anhydride, hexahydro-4-methylphthalic anhydride, itaconic anhydride, 1,2,3,6-tetrahydrophthalic anhydride, 3,4 , 5,6-tetrahydrophthalic anhydride, maleic anhydride, 2-methylmaleic anhydride, 2,3-dimethylmaleic anhydride, 1-cyclopentene-1,2-dicarboxylic anhydride, glutaric anhydride 1-naphthyl acetic anhydride, benzoic anhydride, phenyl succinic anhydride, phenyl maleic anhydride, 2,3-diphenyl maleic anhydride, phthalic anhydride, 4-methylphthalic anhydride, 3, 3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 4,4 ′-(hexafluoropropylidene) diphthalic anhydride, 1,2,4 5-benzenetetracarboxylic anhydride, 1,8-naphthalenedicarboxylic anhydride, 1,4,5,8-naphthalenetetracarboxylic anhydride, etc .; maleic anhydride and a compound having a radical polymerizable double bond Examples of the copolymer include: a copolymer of maleic anhydride and (meth) acrylate; a copolymer of maleic anhydride and styrene; a copolymer of maleic anhydride and vinyl ether.

  Examples of the thiocarboxylic acid anhydride include diacetyl sulfide, thioacetic acid anhydride, thiopropionic acid anhydride, thiobutyric acid anhydride, thioisobutyric acid anhydride, thiovaleric acid anhydride, thiotrimethylacetic acid anhydride, thiohexanoic acid anhydride, thioheptane Acid anhydride, thiodecanoic acid anhydride, thiolauryl acid anhydride, thiomyristyl acid anhydride, thiopalmitic acid anhydride, thiostearyl acid anhydride, thiodocosanoic acid anhydride, thiocrotonic acid anhydride, thioacrylic acid anhydride, thiomethacrylic acid Acid anhydride, thiooleic anhydride, thiolinolenic anhydride, thiochloroacetic anhydride, thioiodoacetic anhydride, thiodichloroacetic anhydride, thiotrifluoroacetic anhydride, thiochlorodifluoroacetic anhydride, thiotrichloroacetic anhydride, Thiopentafluoropropio Acid anhydride, thiopentafluorobutyric anhydride, thiosuccinic anhydride, thiomethyl succinic anhydride, thioisobutyl succinic anhydride, thioitaconic anhydride, thiomaleic anhydride, thioglutaric anhydride, thiophenyl succinic acid Anhydride, thiophenylmaleic acid anhydride, thiophthalic acid anhydride, thiobenzoic acid anhydride, thiodiglycolic acid anhydride, thiolactic acid anhydride and the like can be mentioned.

  As maleimide, for example, succinimide, N-methylsuccinimide, α, α-dimethyl-β-methylsuccinimide, α-methyl-α-propylsuccinimide, maleimide, N-methylmaleimide, N-ethylmaleimide, N -Propylmaleimide, N-tert-butylmaleimide, N-laurylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N- (2-chlorophenyl) maleimide, N-benzylmaleimide, N- (1-pyrenyl) maleimide, 3 -Methyl-N-phenylmaleimide, N, N'-1,2-phenylenedimaleimide, N, N'-1,3-phenylenedimaleimide, N, N'-1,4-phenylenedimaleimide, N, N '-(4-Methyl-1,3-phenylene) bismaleimide, 1,1'-(me (Chylene-1,4-phenylene) bismaleimide, phthalimide, N-methylphthalimide, N-ethylphthalimide, N-propylphthalimide, N-phenylphthalimide, N-benzylphthalimide, pyromellitic diimide; radical polymerization with N-alkylmaleimide Of N-alkylmaleimide and (meth) acrylate; copolymer of N-alkylmaleimide and styrene; copolymer of N-alkylmaleimide and vinyl ether Etc.

  Examples of phosphine oxide include acyl phosphines such as bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide. And oxide.

  Examples of α, α-diketone include 2,4-pentanedione, 3-methyl-2,4-pentanedione, 3-ethyl-2,4-pentanedione, 3-chloro-2,4-pentanedione, 1 , 1,1-trifluoro-2,4-pentanedione, 1,1,1,5,5,5-hexafluoro-2,4-pentanedione, 2,2,6,6-tetramethyl-3, Diketones such as 5-heptanedione, 1-benzoylacetone and dibenzoylmethane; polycarboxylic acid esters such as dimethylmalonate, diethylmalonate, dimethylmethylmalonate, tetraethyl1,1,2,2-ethanetetracarboxylic acid Α-carbonyl-acetate esters such as methyl acetylacetonate, ethylacetylacetonate, methylpropionyl acetate; 3-phenyl 2,4-pentanedione, 3-benzyl-2,4-pentanedione, diethylbenzylmalonate, diethylallylmalonate, diethyldiallylmalonate, diethylethylidenemalonate, triacetylmethane, triethylmethanetricarboxylate, etc. It is done.

  Among these, carboxylic acid anhydrides, carboxylic acid imides, or acylphosphine oxides are preferably used because polymerization of hydrolyzable group-containing polymerizable compounds is fast due to light and is excellent in solubility in the composition. be able to.

  The blending ratio of the photopolymerization initiator is not particularly limited, and may be appropriately selected depending on the combination with the photopolymerizable compound.

  For example, when the photopolymerizable compound is a photocationic polymerizable compound, the photocationic polymerization initiator is preferably blended in an amount of 0.1 to 10 parts by weight with respect to 100 parts by weight of the photocationic polymerizable compound. If the amount is less than 0.1 parts by weight, the amount of the polymerization initiator is too small, and it becomes difficult to cure a long distance from the light source in a region where the presence of the phosphor is small. It may be difficult to reduce the difference in the number of phosphors per volume when assuming a plurality of cylinders with an angle of. On the other hand, when the amount exceeds 10 parts by weight, the amount of the polymerization initiator is too large, light absorption by the initiator becomes strong, and there are cases where it cannot be cured thickly. A more preferable blending amount is 0.5 to 5 parts by weight.

  Moreover, when the said photopolymerizable compound is a radical photopolymerizable compound, it is preferable to mix | blend 0.01-10 weight part of radical photopolymerization initiator with respect to 100 weight part of radical photopolymerizable compounds. The reason why this range is suitable is the same in the case of the above-mentioned photocationic polymerization initiator.

  When the photopolymerizable compound is a hydrolyzable silyl group-containing polymerizable compound, 0.5-10 parts by weight of a diacyl polymerization initiator is added to 100 parts by weight of the hydrolyzable silyl group-containing polymerizable compound. Is preferred. The reason why this range is suitable is the same in the case of the above-mentioned photocationic polymerization initiator.

  The phosphor is not particularly limited, and one or a plurality of phosphors that absorb light emitted from the LED chip to be used, generate fluorescence, and finally realize white light can be appropriately used. . That is, the phosphor may be at least one phosphor that is excited by the light emitted by the LED chip and that can generate white light by the light emitted by the LED chip and the fluorescence emitted by the phosphor.

  For example, when an ultraviolet LED chip is used as the LED chip, for example, a blue phosphor, a red phosphor, and a green phosphor are preferably blended, and when a blue LED chip is used, a green phosphor is preferably used. A phosphor and a red phosphor may be blended, or a yellow phosphor may be blended.

  As the blue phosphor, a phosphor that absorbs ultraviolet rays and emits blue fluorescence can be used. For example, ZnS: Ag, (Sr, Ca, Ba, Mg) 10 (PO4) 6Cl2: Eu, Sr10 ( PO4) 6Cl2: Eu, (Ba, Eu) MgAl10O17, or the like can be used.

Examples of the red phosphor include La ₂ O ₂ S: Eu ³⁺ oxysulfide phosphor, Y ₂ O ₂ S: Eu ³⁺ , Li (Eu, Sm) W ₂ O ₈ , MgSiO ₃ : Mn ^{2+, and the} like. Can be used.

Examples of the green phosphor include Zn ₂ SiO ₄ : Mn ²⁺ , α-sialon: Yb ²⁺ , β-sialon: Yb ²⁺ , ZnS: Cu, Al, and the like.

Examples of the yellow phosphor include Y ₃ AL ₅ O ₁₂ : Ce ³⁺ , α-sialon: Eu ²⁺ , YAG, Ce (cerium) doped YAG, Pr (praseodymium) doped YAG, and the like. Moreover, a perylene-type compound etc. can be used as an organic fluorescent substance.

  The blending amount of the phosphor is not particularly limited. For example, a preferable range of the blending amount of the red phosphor is 0.1 to 20 parts by weight with respect to 100 parts by weight of the photopolymerizable compound. .

  The phosphor is preferably made into nanoparticles when it is desired to reduce light scattering.

  Moreover, in this invention, you may add suitably another component in the said photocurable fluorescent substance containing composition in the range which does not inhibit the objective of this invention. Examples of such other components include ultraviolet absorbers, antioxidants, antioxidants, oxygen scavengers, moisture absorbers, thermally conductive particles, light diffusing materials, and photosensitizers.

(Formation of photocurable phosphor-containing composition layer)
In the method for producing a white LED according to the present invention, first, the photocurable phosphor-containing composition layer is formed on the light emitting surface of the LED chip using the photocurable phosphor-containing composition. The formation method is not particularly limited, and the photocurable phosphor-containing composition may be applied to the light emitting surface of the LED chip by an appropriate method. Examples of such a method include a method of applying a photocurable phosphor-containing composition because the operation is easy. For example, an appropriate application method using a dispenser, dipping, screen printing, inkjet printing, stamping, or the like. Can be adopted.

  In addition, although the photocurable phosphor-containing composition layer is formed on the light emitting surface of the LED chip, the entire LED chip may be covered with the photocurable phosphor-containing composition layer other than the light emitting surface.

  Although the thickness of this photocurable fluorescent substance containing composition layer is not specifically limited, It is preferable to set it as the range of 1-1000 micrometers. If the thickness is less than 1 μm, the phosphor cannot be sufficiently contained, and white light cannot be obtained with certainty. If the thickness exceeds 1000 μm, an uncured portion may increase in the composition after the curing treatment. More preferably, the thickness of the phosphor-containing composition layer is in the range of 10 to 500 μm.

(Curing process)
Next, after forming the photocurable phosphor-containing composition layer, the LED chip is caused to emit light, and the generated light is used to cure the photocurable phosphor-containing composition layer. That is, the phosphor-containing composition layer is cured using the light emission of the LED chip itself. In this case, as described above, even if there is a bias in the dispersion state of the phosphor particles, in a portion where a lot of phosphor exists, light is absorbed by the phosphor in a portion relatively close to the light emitting surface of the LED chip, Curing proceeds at a relatively close portion, and a portion far from the light emitting surface becomes an uncured product. On the other hand, in a portion where the presence of the phosphor particles is small, light reaches a distance far from the light emitting surface and curing proceeds, and the thickness of the uncured product portion becomes thin.

(Removal of uncured material)
Next, after the curing step, the uncured product of the photocurable phosphor-containing composition is removed so as to leave a cured product of the photocurable phosphor-containing composition. By removing the uncured material, it is possible to reduce the difference in the number of phosphors per volume between the cylinders having the arbitrary light beam as the central axis. That is, when there are many phosphors in a certain optical path, as described above, curing proceeds only to a short distance from the light emitting surface, and the thickness of the uncured product layer increases. On the other hand, in a certain optical path, when there are few phosphors, curing proceeds relatively far from the light emitting surface, and the thickness of the uncured product is reduced. Therefore, by removing the uncured product portion, the difference in the number of phosphors between the cylinders having an arbitrary light beam as the central axis can be reduced, and uneven color and uneven light emission can be prevented.

  The method for removing the uncured product is not particularly limited, and an appropriate removal method such as a method using a solvent that can remove the uncured product but does not dissolve the cured product can be used. Examples thereof include alcohol solvents, ether solvents, ester solvents, carbonate solvents, hydrocarbon solvents, halogen solvents and the like. As a solvent having excellent drying properties after washing, a solvent having a boiling point of 150 ° C. or lower can be suitably used. More preferably, a solvent of 100 ° C. or lower can be preferably used.

(Sealing)
In the method for producing a white LED according to the present invention, preferably, after removing the uncured product, the cured product of the photocurable phosphor-containing composition and the LED chip are sealed with a sealing material. The sealing material is not particularly limited as long as it is a resin material having translucency, and examples thereof include an epoxy resin and an acrylic resin. The sealing method is not particularly limited. For example, an LED chip in which a cured material layer of a photocurable phosphor-containing composition from which an uncured material has been removed by previously injecting a sealing material into a mold is formed. It is possible to use an arbitrary method such as a method of immersing and curing in a state bonded to a lead frame, a method of injecting a sealing material into a mold frame in which the LED chip formed with the cured product layer is inserted, and a method of curing. it can.

  It is desirable that the refractive index of the sealing material has a small difference from the refractive index of the cured product of the phosphor-containing composition layer, and this refractive index difference is preferably 0.1 or less. desirable.

  When the refractive index difference is larger than 0.1, reflection or the like occurs at the interface between the sealing layer and the cured product layer of the photocurable phosphor-containing composition layer, and the visibility of white light may be deteriorated.

  The method for injecting the sealing material is not particularly limited, and an appropriate method such as an injection method using a dispenser can also be used. Also, various methods such as transfer molding and injection molding can be used for the molding method using the mold.

  Furthermore, as another sealing method, a sealing material is dropped onto an LED chip on which a cured material layer of the phosphor-containing composition is formed, a printing method such as stencil printing or screen printing, and sealing through a mask. You may use the method of apply | coating and hardening a material, the method of inject | pouring a sealing material etc. into the cup etc. which arrange | positioned the LED chip in the bottom part, and hardening.

(Product form)
In addition, in the manufacturing method of LED of this invention, after hardening | curing the said photocurable fluorescent substance containing composition layer and removing an uncured thing, or by further sealing by the said sealing material, of course, However, it is necessary to join a lead wire or a terminal for supplying power to the LED chip. Further, it may be formed as an LED component having a lead wire, a terminal, or the like, or housed in some package so that the light emitting surface side is exposed, and the package wiring and the LED chip are electrically connected by the lead wire or the like. It is good also as a component of the form connected and accommodated in the package.

  According to the method for producing a white light emitting diode according to the present invention, the photocurable phosphor-containing composition layer is formed on the light emitting surface of the LED chip, and the light emitting diode chip is allowed to emit light. The phosphor-containing composition layer is cured, and the uncured product is removed so as to leave this cured product, whereby the light emitted from the light emitting surface of the light emitting diode chip in an arbitrary direction is the central axis, and the cured product layer It is possible to reduce the difference in the number of phosphor particles between the cylinders having the length from the inner surface to the outer surface. Therefore, it is possible to provide a white light emitting diode with less color unevenness.

  Hereinafter, the present invention will be clarified by giving specific examples and comparative examples of the present invention. In addition, this invention is not limited to a following example.

(Materials prepared)
(1) Photopolymerizable compound Epoxy compound: manufactured by Tohto Kasei Co., Ltd., hydrogenated bis A type epoxy resin, trade name: ST-3000
Radical polymerizable compound: manufactured by Kyoeisha Chemical Co., Ltd., dimethylol-tricyclodecane diacrylate, product name: light acrylate DCP-A

(2) Photopolymerization initiator Photocationic polymerization initiator: manufactured by Adeka Corporation, trade name: SP-170, triarylsulfonium salt compound, photo radical polymerization initiator: manufactured by Ciba Specialty Chemicals, acylphosphine compound, Product Name Irgacure 819

(3) Phosphor Blue phosphor: manufactured by Kasei Optonics Co., Ltd., trade name: P22-B1
Green phosphor: manufactured by Kasei Optonics, trade name: P22-GN4
Red phosphor: manufactured by Kasei Optonics, trade name: P22-RE3
As shown in Table 1 below, SP-170 is used as a photopolymerization initiator with respect to 100 parts by weight of a hydrogenated bis A type epoxy resin (manufactured by Toto Kasei Co., Ltd., trade name: ST-3000) as the photopolymerizable compound. 3 parts by weight of P22-B1 (ZnS: Ag, blue) manufactured by Kasei Optonics as a phosphor, P22-GN4 (ZnS: Cu, Al, green) manufactured by Kasei Optonics, P22-RE3 manufactured by Kasei Optonics 0.5 parts by weight of each (Y ₂ O ₂ S: Eu, red) was blended and mixed to obtain a photocurable phosphor-containing composition.

  The above photocurable phosphor-containing composition was applied using a dispenser so as to cover the entire light emitting surface of an LED chip (product number: NCCU033, ultraviolet, emission wavelength of about 365 nm) manufactured by Nichia Corporation. The containing composition layer was formed to a thickness of 300 μm.

  Next, a voltage of 3.6 V was applied to the LED chip on which the photocurable phosphor-containing composition layer was formed for 60 seconds to cause the LED chip to emit light. By this light emission, curing proceeded in the photocurable phosphor-containing composition layer.

  Next, ethanol was used as the solvent, and the uncured product was removed by immersing the LED chip in which the photocurable phosphor-containing composition layer had been cured in a container filled with the solvent. 5 white LEDs were obtained.

(Example 2)
Five LEDs of Example 2 were obtained in the same manner as Example 1 except that the used materials and blending ratio were changed as shown in Table 1 below.

(Comparative Example 1)
Using the same photocurable phosphor-containing composition as in Example 1, a photocurable phosphor-containing composition layer was formed on the light emitting surface of the LED chip in the same manner as in Example 1. Thereafter, without emitting the LED chip, light was irradiated from the outside with a high-pressure mercury lamp to cure the photocurable phosphor-containing composition layer. In this way, 5 LEDs of Comparative Example 1 were obtained.

(Comparative Example 2)
In place of the photocurable phosphor-containing composition of Example 1, the same LED as that of Comparative Example 1 was used except that the same photocurable phosphor-containing composition as in Example 2 was used. I got it.

(Evaluation of Examples and Comparative Examples)
About each LED obtained in Examples 1-2 and Comparative Examples 1-2, the DC voltage of 3.6V was applied, the luminescent color was evaluated visually, and the color nonuniformity was evaluated in the following ways.

  Color unevenness evaluation method: Evaluation was performed in the self-luminous substance specifying mode using a Murakami Color Research Laboratory Co., Ltd. three-dimensional variable angle spectrocolorimetry system, GCMS-14. First, after fairing the device with the standard white plate, set the light emitting surface of the LED to be the same height as the surface of the standard white plate when fairing the device, turn on the LED and the light intensity is Measurement was started after confirming stability.

  The spectroscopic measurement was performed in the field of 2 degrees from the normal direction and the direction inclined by 45 ° from the normal direction with respect to the LED chip surface. The emission intensity I (0) at a wavelength of 550 nm in the normal direction and the emission intensity I (45) at a wavelength of 550 nm from a direction inclined by 45 ° from the normal line are measured, and the ratio [I (45) / I (0)] n = 5 variation was calculated, and when the difference between the maximum value and the minimum value of the ratio was 0.1 or less, there was no color unevenness (◯ evaluation), and when it exceeded 0.1, there was color unevenness (× evaluation).

  The results are also shown in Table 1 below.

Claims (6)

A step of forming a photocurable phosphor-containing composition layer on a light emitting surface of a light emitting diode chip using a photocurable phosphor-containing composition containing a photopolymerizable compound, a photopolymerization initiator, and a phosphor;
Light-emitting the light-emitting diode chip, and using the generated light to cure the photocurable phosphor-containing composition layer;
A step of removing an uncured product of the photocurable phosphor-containing composition so as to leave a cured product of the photocurable phosphor-containing composition after the curing step. Diode manufacturing method.   After removing the uncured material of the photocurable phosphor-containing composition, the cured product of the photocurable phosphor-containing composition provided on the light emitting surface of the light emitting diode chip and the light emitting diode chip is sealed with a sealing material. The manufacturing method of the white light emitting diode of Claim 1 further equipped with the process to seal. A photocurable phosphor-containing composition used in the method for producing a white light emitting diode according to claim 1 or 2,
A photocurable phosphor-containing composition comprising a photopolymerizable compound, a photopolymerization initiator, and a phosphor.   The photocurable phosphor-containing composition according to claim 3, wherein the photopolymerizable compound is a photocationic polymerizable compound and / or a photoradical polymerizable compound.   The photocurable phosphor-containing composition according to claim 3 or 4, wherein the photopolymerizable compound is a photocurable epoxy resin.   The phosphor is at least one phosphor that is excited by light emitted from a light-emitting diode chip and can generate white light by light emitted from the light-emitting diode chip and fluorescence emitted from the phosphor. The photocurable fluorescent substance-containing composition according to any one of claims 3 to 5.