JP2008124117A - Light-emitting device and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting device and a manufacturing method thereof, capable of realizing a white LED having less color variation by proposing a hermetically sealing method having sufficient durability for the heat resistant temperature of an organic phosphor in hermetically sealing the organic phosphor. <P>SOLUTION: The light-emitting device is provided with a cylindrical stem having at least two insulated lead wires attached thereto; a light-emitting element; and a metal cap fitted on the stem, having a transparent member for light emission provided on the top surface of itself, coated with the organic phosphor in its inside and filled with an inactive liquid for cooling in its inside. The manufacturing method includes: mounting the light-emitting element on the stem, press-fitting the stem to the metal cap and hermetically sealing the organic phosphor. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a light emitting device and a manufacturing method thereof, and more particularly to a light emitting device capable of realizing a white LED and a manufacturing method thereof.

Conventionally, as a light emitting device, an LED element is mounted on a lead frame or an insulating substrate (glass epoxy, ceramic, MID) with Ag paste or the like, connected with wire bond, and sealed with epoxy resin or silicone resin. It was an LED lamp. In the case of a white LED, a GaN-based blue element is used, and a YAG phosphor is mixed in the resin to constitute an LED lamp, and a pseudo white color is realized with yellow as excitation light and blue transmitted through the YAG phosphor. (Patent Document 1).
However, since all of the YAG phosphors are inorganic phosphors, the excitation spectrum is wide, the matching with the liquid crystal color filter is poor, and there are problems such as efficiency and crosstalk.
Therefore, in order to expand color reproducibility, in addition to the YAG phosphor in the resin, a red phosphor or a red LED is added.
Among these, the diketone proposed in Patent Documents 2 and 3 or the Eu complex having the carboxylic acid proposed in Patent Document 4 as a ligand has high emission intensity and excellent color rendering. It is a red luminescent material with excellent color reproducibility.
However, these complexes are sensitive to oxygen and humidity and require hermetic sealing.
Conventionally, as a method for performing such sealing, a phosphor layer is formed on the inner wall of the outer cap of the light emitting element by coating, and the inside is sealed in a vacuum or an inert gas atmosphere. Has been proposed (Patent Document 5). However, in this proposal, there is no disclosure about the material of the cap and the temperature at which the sealing is performed, and the sealing is not actually performed.
In addition, there is also a proposal regarding the use of an organic polymer complex as a light emitter (Patent Document 6), but there is no disclosure regarding a specific sealing method.
JP 2006-49657 A JP 2005-252250 A Japanese Patent Laid-Open No. 2003-81986 JP 2005-8872 A JP 2004-352928 A JP 2002-163902 A JP-A-6-97320 JP 2001-36148 A

The organic phosphor has a low heat-resistant temperature. For example, the temperature during sealing cannot be increased to 200 ° C. or higher.
Accordingly, an object of the present invention is to provide a light-emitting device capable of realizing a white LED with little color variation by proposing an air-tight sealing method that can sufficiently withstand the heat-resistant temperature in hermetically sealing an organic phosphor. It is to provide a manufacturing method.

Such a purpose is to have a cylindrical stem with at least two insulated leads, a light emitting element, a fitting for the stem, and a transparent member for light emission on its top surface, and A metal cap filled with an organic phosphor on the inner surface and filled with an inert liquid for cooling; and the light-emitting element is mounted on the stem, and the stem is press-fitted into the metal cap. The organic phosphor is hermetically sealed and realized by a light emitting device.
In this case, the light emitting element is preferably a near ultraviolet LED that emits near ultraviolet light.
The transparent member is preferably a glass plate or a glass lens.
Moreover, it is preferable that the said organic type fluorescent substance is apply | coated to at least one part of the top | upper surface and / or inner peripheral surface of the said metal cap, and is airtightly sealed.
Further, it is preferable to provide a metal cushioning material as a cushioning material when the metal cap is press-fitted to the outer periphery of the stem, and the metal cushioning material is preferably a soft metal plating film, and further, a solder material It is preferable that the plating film. Moreover, it is preferable that the solder material is formed from a SnCu alloy.
Further, the organic phosphor is preferably a red phosphor complex.
The red phosphor complex is preferably a Eu diketone or a carboxylic acid complex.
In addition to the organic phosphor, it is preferable to use a blue and / or green phosphor.
The inert liquid preferably has a thermal conductivity of 0.01 to 0.1 W / mK, and more preferably a fluorine-based or hydrocarbon-based compound.
In this case, the light emitting element is mounted on a cylindrical stem with at least two insulated lead wires, and a transparent member for light emission is integrated on the top surface of the metal cap, In an inert atmosphere, an organic phosphor is applied and filled with an inert liquid for cooling, and a solder material is applied to the outer peripheral portion of the stem that becomes a joint portion between the stem and the metal cap, It is preferable to manufacture the light emitting device by hermetically sealing the organic phosphor by press-fitting the stem into the metal cap at room temperature.

According to the present invention, since the application amount and position of the organic phosphor can be controlled without accompanying deterioration of the characteristics of the organic phosphor, a white LED with little color variation can be realized. Moreover, the convection of the inert liquid for cooling with which it filled in the metal cap generate | occur | produces with the heat which arises by lighting white LED. Thereby, heat can also be radiated to the metal cap, and temperature rise can be suppressed. For this reason, the original performance can be exhibited. Moreover, the light extraction efficiency is improved by filling the inert liquid. In addition, since the influence of heat generation due to long-term use of the light emitting element can be effectively avoided, the lifetime is improved. Since the near-ultraviolet light emitted from the near-ultraviolet LED is wavelength-converted by the phosphor, the color coordinates do not shift due to temperature or long-term deterioration. In addition, since the light wavelength-converted by the organic phosphor is sharp, a white LED with high color reproducibility and saturation can be realized.
References 7 and 8 describe that the cap is filled with an inert liquid while the light emitting element is hermetically sealed. However, these do not use a metal cap as in the present invention, and do not apply an organic phosphor inside the metal cap, and the effect of the present invention cannot be expected.

As shown in FIG. 1, the light emitting device 10 in the present embodiment includes a cylindrical stem 2 with at least two insulated lead wires 3, a light emitting element 1 of a near-ultraviolet LED, and a stem 2. The glass 6 is preferably used as a transparent member for light emission on the top surface, and an organic phosphor 7 is applied to the inner surface of the glass 6, and an inert liquid 9 for cooling is further provided therein. FIG. 1 shows an example in which the organic phosphor 7 is applied to the top surface and the inner peripheral surface of the metal cap 4 (FIGS. 2, 3). The light emitting element 1 is mounted on the stem 2, the stem 2 is press-fitted into the metal cap 4, and the organic phosphor 7 is hermetically sealed together with the inert liquid 9.
In the example shown in FIG. 1, the example in which the stem 2 and the light emitting element 1 are integrated is shown. However, the two may be separate, and the stem 2 is integrated with a separate frame. The frame body may be provided in the stem body. In any case, the lead 3 and the light emitting element 1 provided integrally with the stem body are electrically connected via the wire 8 (see FIGS. 2 and 3).
In this case, sealing hermetically may be vacuum or sealed in an inert gas atmosphere such as nitrogen, Ar, F, etc., and the oxygen gas concentration is 100 ppm or less, preferably 20 ppm or less. It is preferable to hermetically seal the atmosphere.

The metal cap 4 is fitted to the stem 2 and encloses or seals a transparent member. For this reason, a glass material is preferably used as the transparent member. Of these materials, for example, Kovar, 42-Ni and the like are preferable.
The metal cap 4 has a transparent member, preferably glass 6 on the top surface, and light is emitted through the glass 6. The glass 6 at this time may be a glass plate, and if a spherical lens, convex lens, concave lens, or the like is used as the glass lens, light can be condensed or diffused to emit light, and light utilization efficiency can be improved. Can be improved. Preferably, the glass translucent member is preferably bonded and integrated with the top surface of the metal gap 4. This glass is preferably transparent in the visible range and high in strength.
What is necessary is just to employ | adopt the size of the metal cap 4 from the outer diameters 1-6 mm. The length may be arbitrarily set according to the intended use.
The Young's modulus of the material of the glass 6 used for the top surface is about 50-80 MPa, the density is 2-3 g / cm ³ , the refractive index is about 1.4-1.6, and the softening point is 600 It may be in an arbitrary range of ˜1600 ° C. Note that the transmittance in the visible region is 400 nm or more, preferably 80% or more, and particularly preferably 85% or more.
The transmittance in the near ultraviolet region of 350 nm or less is preferably 40% or less.
As such a glass material, aluminoborosilicate glass is preferable.
As the aluminoborosilicate glass, for example, SiO ₂ 50-70%, Al ₂ O ₃ 10-20%, B ₂ O ₃ 3-10%, Na ₂ O, K ₂ O total 1% or less, MgO, CaO A total of 15 to 30% is preferable.
This glass material is integrated with the metal cap, and the sealing temperature may be appropriately selected from a temperature of 600 to 1000 ° C., for example.

The method for press-fitting the stem 2 into the metal cap 4 is not particularly limited. As shown in FIGS. 2 and 3, the outer periphery of the stem 2 is plated with a metal that is softer than the constituent material of the metal cap such as solder plating. It is preferable to apply such a plating film as a buffer material when the metal cap 4 is press-fitted. As such a soft metal, solder is preferably used.
According to such sealing by press-fitting, a metal cap to which an organic phosphor and an inert liquid are previously applied in an airtight atmosphere can be hermetically sealed at room temperature.
The solder material used for solder plating is preferably an SnCu-based alloy, and the alloy composition is not particularly limited, and Cu is preferably 1 to 10%, more preferably 2 to 3%.

A more efficient method for performing such press-fit sealing is shown.
First, a transparent member is integrated with the top surface of the metal cap 4. The integration temperature is as described above. Next, an organic phosphor 7 is applied to the metal cap 4 integrated with a glass material, and an inert liquid 9 is applied to the top surface in an inert atmosphere. In the example shown in FIGS. 2 and 3, the stem 2 is press-fitted into the metal cap 4 and sealed in a vacuum atmosphere or an inert gas atmosphere. The organic phosphor 7 is applied to the inside of the metal cap 4 by coating or the like. For example, the organic phosphor 7 is dispersed in a silicate resin or the like to prepare a paste, and then the paste is once injected into the metal cap 4 and then discharged after being injected. Then, a film such as a silicate resin in which the organic phosphor 7 is dispersed is formed on the inner peripheral surface and the top surface of the metal cap 4. Thereafter, for example, the phosphor is fixed to the inner peripheral surface and the top surface by heating at a temperature of about 150 ° C. or lower.
As a material for preparing the paste, silicone resin, polyvinyl alcohol, or the like can be used instead of the silicate resin. In addition to the above silicate resin, silicone resin, polyvinyl alcohol, or the like can also be used as various translucent fillers. Also in this case, the heating temperature is preferably about 150 ° C. or less, which is the temperature at which the phosphor does not melt.
In the example shown in FIGS. 2 and 3, the organic phosphor 7 is applied to the entire top surface and inner peripheral surface of the metal cap 4. However, the present invention is not limited to this, and the inner peripheral surface is excluded. It may be a part of the inner surface, such as the top surface, particularly only the inner surface facing the cap of the transparent member.

The inert liquid is preferably excellent in thermal conductivity and electrical insulation, preferably thermally and chemically stable, and has a thermal conductivity (25 ° C.) of 0.01 to 0.1 W / mK. Is more preferable, and about 0.06 to 0.07 W / mK is more preferable. The melting point is preferably −160 to −30 ° C., more preferably −140 to −40 ° C., and the boiling point is preferably 50 to 180 ° C., more preferably 100 to 160 ° C. Specific examples include fluorine-based or hydrocarbon-based compounds. As fluorine compounds, fluorine inert liquids (product names: FC-40, FC-43, FC-3283, etc.) marketed under the trade name of Florinart from 3M, and commercially available under the trade name of Novec Hydrofluoroethers (product names: HFE-7100, HFE-7100DL, HFE-7200, etc.) and the like. Moreover, paraffin etc. are mentioned as a hydrocarbon type compound. Among these, it is preferable to use a fluorine-based compound.
The inert liquid 9 may be filled in the metal cap 4 under an inert gas atmosphere as in the case of the application of the organic phosphor 7.

Next, solder 5 is applied to the outer peripheral surface (side surface) of the stem 2.
Solder may also be applied to the joint portion of the metal cap 4 with the stem 2. And the stem 2 which mounted the LED light emitting element 1 in the metal cap 4 is press-fitted with a predetermined pressure at normal temperature.
FIG. 4 shows an example in which a spherical glass lens 61 is used as the transparent member.

Next, the organic phosphor will be described.
In the present invention, an organic fluorescent complex is used as the phosphor. In addition, organic phosphors such as polymers containing various phosphor portions in the main chain can also be used. Although it does not specifically limit as a fluorescent complex, Usually, the rare earth ion complex which is a complex of the 1 type (s) or 2 or more types of ligand anion and the ion of a trivalent rare earth element is used. Examples of rare earth elements include Sm, Eu, Tb, Ey, Tm and the like. Of these, an Eu (europium) element is preferable as the red phosphor, a Tm (thulium) element as the blue phosphor, and an ion complex of Tb (terbium) element as the green phosphor.
Examples of such fluorescent complexes include JP-A-2005-8872, JP-A-2004-356358, JP-A-2004-352928, JP-A-2005-41941, JP-A-2005-41942, JP 2005-112923 A, JP 2005-252250 A, JP 2003-81986 A, JP 3668966 A, JP 2003-147346 A, International Publication No. 2004/104136 Pamphlet, International Publication No. 2004. / 107459 pamphlet, the international publication 2005/75598 pamphlet, etc. can be illustrated.

In particular, a europium complex which is a red fluorescent complex is preferably used. In the present invention, a polymer containing a phosphor substance in the main chain can be used, but in terms of luminous efficiency, it is preferable to use a diketone or a europium complex having a carboxylic acid as a ligand as the red phosphor. .
As a preferable example of such a complex, first, a complex having a specific β-diketone anion represented by the following formula (1) as a ligand is exemplified.

  In the formula (1), p is 1 or 2, and q is 1, 2, 3 or 4. X may be the same or different and each is a hydrogen atom, deuterium atom, halogen atom (fluorine, chlorine, bromine, iodine), group having 1 to 20 carbon atoms, hydroxyl group, nitro group, amino group, sulfonyl Represents a group, a cyano group, a silyl group, a phosphonic acid group, a diazo group, or a mercapto group. Y may be the same or different and each represents a group having 1 to 20 carbon atoms, a hydroxyl group, a nitro group, an amino group, a sulfonyl group, a cyano group, a silyl group, a phosphonic acid group, a diazo group, or a mercapto group. To express. Z represents a hydrogen atom or a deuterium atom.

As the group having 1 to 20 carbon atoms;
A linear or branched alkyl group (C _n H _{2n + 1} ; n = 1 to 20), a perfluoroalkyl group (C _n F _{2n + 1} ; n = 1 to 20), a perchloroalkyl group (C a perhalogenated alkyl group having a straight chain or a branch, such as _n Cl _{2n + 1} ; n = 1 to 20);
Straight or branched alkenyl groups (vinyl group, allyl group, butenyl group), perfluoroalkenyl groups (perfluorovinyl group, perfluoroallyl group, perfluorobutenyl group), perchloroalkenyl groups, etc. A perhalogenated alkenyl group having a chain or a branch;
Cycloalkyl group _{(C n H 2n-1;} n = 3~20), and perfluoro cycloalkyl group _{(C n F 2n-1;} n = 3~20), perchlorethylene alkyl group _{(C n Cl 2n-1} A perhalogenated alkyl group having a straight chain or a branch, such as n = 3 to 20);
A cycloalkenyl group (cyclopenten-yl group, cyclohexen-yl group and the like), and a perhalogenated alkenyl group such as a perfluorocycloalkenyl group and a perchloroalkenyl group;
Aromatic groups such as phenyl, naphthyl and biphenyl, and perhalogenated aromatics such as perfluorophenyl, perfluoronaphthyl, perfluorobiphenyl, perchlorophenyl, perchloronaphthyl and perchlorobiphenyl Group;
Heteroaromatic groups such as pyridyl groups and perhalogenated heteroaromatic groups such as perfluoropyridyl groups;
Aralkyl groups such as benzyl group and phenethyl group, and perhalogenated aralkyl groups such as perfluorobenzyl group;
Etc.

The group having 1 to 20 carbon atoms represented by X and Y is a deuterium atom, a halogen atom (fluorine, chlorine, bromine, iodine), a hydroxyl group, a nitro group, an amino group, a sulfonyl group, a cyano group, if necessary. It may be substituted with a substituent such as a silyl group, a phosphonic acid group, a diazo group, or a mercapto group.
Further, an ether, ester, or ketone structure may be formed by interposing one or more —O—, —COO—, or —CO— between C—C single bonds at arbitrary positions of a group having 1 to 20 carbon atoms. Good.

The europium complex of the formula (1) in which X and Y are alkenyl groups may be polymerized with an olefin such as ethylene and propylene and a halogenated olefin as necessary to form a high-molecular europium complex.

  In the compound represented by the formula (1), the above-mentioned compounds can be used as Y. In particular, in view of stability and emission intensity of a solid support containing a europium complex or a europium complex, the number of carbon atoms 1-4 alkyl groups, perhalogenated alkyl groups, aromatic groups, perhalogenated aromatic groups, heteroaromatic groups, perhalogenated heteroaromatic groups are preferred, among which perfluoroalkyl groups, aromatic groups, Heteroaromatic groups are most preferred.

  p is 1 or 2, but is preferably 2. q is any one of 1 to 4, and is preferably 3.

A complex represented by the formula (1) in which Z is a deuterium atom D is a deuterium substitution reaction between the complex represented by the formula (1) in which Z is a hydrogen atom and a deuterating agent. Is obtained. Examples of the deuterating agent used include protic compounds containing deuterium, specifically, deuterated alcohols such as deuterated water, deuterated methanol, and deuterated ethanol, deuterated hydrogen chloride, and deuterated alkali. It is done. In order to accelerate the reaction, a base agent or additive such as trimethylamine or triethylamine may be added. The deuterium substitution reaction is obtained by mixing the complex represented by the formula (1) in which Z is a hydrogen atom and a deuterating agent, but an aprotic solvent may be added during the reaction. Examples of aprotic solvents include ketone solvents such as acetone and methyl ethyl ketone, ether solvents such as diethyl ether and tetrahydrofuran, halogen solvents such as chloroform and methylene chloride, dimethyl sulfoxide (DMSO), and dimethylformamide (DMF). It is done. Among these, a solvent in which the formula (1) is soluble and soluble is preferable.

Moreover, as a quantity of the deuterating agent to be used, about 1-100 mass parts is illustrated with respect to the total amount (it is set as 1 mass part) of the complex represented by Formula (1), Preferably it is 1-20 mass parts Degree.

  The mixing method is not particularly limited, and is performed at a temperature of room temperature to 150 ° C., preferably at a temperature of 30 ° C. to 100 ° C., with stirring as necessary for 0.1 to 100 hours, preferably 0.1 to 20 hours. Mix for hours.

  After the stirring, the deuterating agent and the solvent are distilled off to obtain a deuterated complex. Moreover, it can further refine | purify by methods, such as recrystallization, column chromatography, and sublimation, as needed.

As a specific example of the complex represented by the formula (1), according to the notation of the formula (1),
A compound represented by a combination of X = H, Y = CF ₃ , Z = H, p = 2 and q = 3 (complex compound 1-1),
A compound represented by a combination of X = H, Y = CF ₃ , Z = D, p = 2, q = 3 (complex compound 1-2),
Etc.

Moreover, as a preferable example of a europium complex, the complex which uses the anion of (beta) -diketone which has a substituent containing an aromatic ring, or the carboxylate ion which has a substituent containing an aromatic group as a ligand is mentioned.

Examples of the complex having a β-diketone anion having a substituent containing an aromatic ring as a ligand include a europium complex represented by the following formula (2), (3) or (4).
(R ₁ ) ₃ Eu
(2)
(R ₁ ) ₃ Eu (R ₂ ) ₂
(3)
[(R ₁ ) ₄ Eu] ⁻ R ₃ ⁺
(4)
In the formulas (2), (3) and (4), R ₁ is an anion of a β-diketone having a substituent containing an aromatic ring, R ₂ is an auxiliary ligand composed of a Lewis base, and R ₃ ⁺ Is a quaternary ammonium ion.

The β-diketone having a substituent containing an aromatic ring in the formulas (2), (3) and (4) preferably has at least one aromatic group. And a group derived from an aromatic hydrocarbon compound or an aromatic heterocyclic (heterocyclic) compound which may have a group.
Examples of the aromatic hydrocarbon compound include benzene, naphthalene, phenanthrene, and the like. Examples of the aromatic heterocyclic compound include heterocyclic compounds containing oxygen, nitrogen, and sulfur atoms such as furan, thiophene, pyrazoline, pyridine, carbazole, dibenzofuran, and dibenzothiophene.

  Examples of the substituent of these aromatic hydrocarbon compounds or aromatic heterocyclic compounds include alkyl groups such as methyl, ethyl, propyl, and butyl; fluoroalkyl groups such as trifluoromethyl and pentafluoromethyl; methoxy, Alkoxy groups such as ethoxy; aryloxy groups such as benzyl and phenethyl; hydroxyl groups; allyl groups; acyl groups such as acetyl and propionyl; acyloxy groups such as acetoxy, propionyloxy and benzoyloxy; alkoxycarbonyls such as methoxycarbonyl and ethoxycarbonyl Group; aryloxycarbonyl group such as phenoxycarbonyl; carboxyl group; carbamoyl group; amino group; substituted dimethylamino, diethylamino, methylbenzylamino, diphenylamino, acetylmethylamino, etc. Amino group; methylthio, ethylthio, phenylthio, substituted thio group such as benzylthio; a mercapto group; ethylsulfonyl, substituted sulfonyl groups such as phenylsulfonyl; cyano group; fluoro, chloro, bromo, and the like halogen groups iodine and the like. These substituents may be bonded to each other to form a ring.

  Examples of the substituent other than the aromatic group constituting the β-diketone include the same substituents as those of the aromatic hydrocarbon compound or aromatic heterocyclic compound described above (however, the halogen group is excluded). Specific examples (1 to 19) of β-diketone having a substituent containing an aromatic ring are shown below, but the present invention is not limited thereto.

  Specific examples (1 to 7) of the europium complex represented by the formula (2) are shown below, but the present invention is not limited thereto.

Next, the europium complex represented by Formula (3) will be described. Is not particularly limited as consisting Lewis base auxiliary ligand (R ₂₎ in formula (3) it is generally selected from a Lewis base compound having capable of coordinating nitrogen atom or an oxygen atom in the europium ions. Examples thereof include amines, amine oxides, phosphine oxides, sulfoxides and the like which may have a substituent. The two Lewis base compounds used as auxiliary ligands may be different from each other, or two compounds may form one compound.

  Specifically, for example, amines include pyridine, pyrazine, quinoline, isoquinoline, phenanthridine, 2,2'-bipyridine, 1,10-phenanthroline, and the like. Examples of the amine oxide include N-oxides of the above amines such as pyridine-N-oxide and 2,2'-bipyridine-N, N'-dioxide. Examples of the phosphine oxide include triphenylphosphine oxide, trimethylphosphine oxide, and trioctylphosphine oxide. Examples of the sulfoxide include diphenyl sulfoxide and dioctyl sulfoxide. Examples of the substituent that substitutes for these include the substituents described above. Among these, an alkyl group, an aryl group, an alkoxyl group, an aralkyl group, an aryloxy group, a halogen group and the like are particularly preferable.

  Among these Lewis base compounds, when two atoms coordinated in the molecule, such as a nitrogen atom, such as bipyridine and phenanthroline, are present, two auxiliary ligands can be combined with one Lewis base compound. You may do the same work. In addition, as a substituent substituted by these Lewis base compounds, the substituent mentioned above is illustrated. Among these, an alkyl group, an aryl group, an alkoxyl group, an aralkyl group, an aryloxy group, a halogen group and the like are particularly preferable.

Specific examples (1 to 23) of the Lewis base compound (R ₂ ) used as the auxiliary ligand are exemplified below, but the present invention is not limited thereto.

  Specific examples (1 to 13) of the europium complex represented by the formula (3) are shown below, but the present invention is not limited thereto.

  Next, the europium complex represented by Formula (4) will be described. Examples of ammonium ions in formula (4) include quaternary ammonium salts derived from alkylamines, arylamines, and aralkyl ions. Examples of amine substituents include alkyl groups such as methyl, ethyl, propyl, butyl, hexyl and octyl; substituted alkyl groups such as hydroxyethyl and methoxyethyl; aryl groups such as phenyl and tolyl; arylalkyls such as benzyl and phenethyl groups Groups and the like.

  Specific examples (1 to 5) of the europium complex represented by the formula (4) are shown below, but the present invention is not limited thereto.

On the other hand, examples of the complex having a carboxylate ion having a substituent containing an aromatic group as a ligand include a europium complex represented by the formula (5).
_{(R 4 - (X 1)} n -COO) 3 Eu (R 5) 2
(5)
In Formula (5), R ₄ is a group containing at least one aromatic hydrocarbon ring or aromatic heterocyclic ring which may have a substituent, X ₁ is a divalent linking group, and n is 0 or 1 and R ₅ is an auxiliary ligand comprising a Lewis base.

  The ligand represented by the formula (5) includes at least one aromatic ring, has 8 or more π electrons, and uses a carboxylate ion constituting a π electron conjugated system as a ligand. This is preferable from the viewpoint of the absorption wavelength region. The number of aromatic rings is not particularly limited as long as the triplet energy of the carboxylate ion matrix compound is higher than the europium ion excited state energy level. It is preferable to use a group heterocycle. When the number of aromatic rings is 4 or more, for example, a compound such as pyrene having 4 or more aromatic rings has low triplet energy excited by absorbing light from a semiconductor light emitting device or the like, The europium complex may not emit light.

R ₄ in formula (5) is preferably a monovalent group derived from a tricyclic or lower aromatic ring which may have a substituent, or a heteroaromatic ring. Examples of the aromatic ring include aromatic monocyclic hydrocarbons or aromatic condensed polycyclic hydrocarbons such as benzene, naphthalene, indene, biphenylene, acenaphthene, fluorene, phenanthrene, tetralin, indane, and indene; benzoquinone, naphthoquinone, And compounds derived from aromatic hydrocarbons such as anthraquinone. Heteroaromatic rings include aromatic monocyclic heterocycles such as furan, pyrrole, thiophene, oxazole, isoxazole, thiazole, imidazole, pyridine, benzofuran, benzothiophene, coumarin, benzopyran, carbazole, xanthene, quinoline, and triazine. Examples thereof include a ring or an aromatic condensed polycyclic heterocycle.

Examples of the substituent that R ₄ may have include alkyl groups such as methyl, ethyl, propyl and butyl; fluoroalkyl groups such as trifluoromethyl and pentafluoroethyl; cycloalkyl groups such as cyclohexyl group; ethynyl Groups; arylethynyl groups such as phenylethynyl, pyridylethynyl and thienylethynyl; alkoxy groups such as methoxy and ethoxy; aryl groups such as phenyl and naphthyl; aralkyl groups such as benzyl and phenethyl; aryloxy such as phenoxy, naphthoxy and biphenyloxy Hydroxyl group; allyl group; acyl groups such as acetyl, propionyl, benzoyl, toluoyl, biphenylcarbonyl; acyloxy groups such as acetoxy, propionyloxy, benzoyloxy; methoxycarbonyl, ethoxycarbonyl An alkoxy group such as phenoxycarbonyl; a carboxyl group; a carbamoyl group; an amino group; a substituted amino group such as dimethylamino, diethylamino, methylbenzylamino, diphenylamino, acetylmethylamino; methylthio, ethylthio, phenylthio; And substituted thio groups such as benzylthio; mercapto groups; substituted sulfonyl groups such as ethylsulfonyl and phenylsulfonyl groups; cyano groups; halogen groups such as fluoro, chloro, bromo and iodo. Among these, an alkyl group, an alkoxy group, an aryl group, a cycloalkyl group, a cycloalkyl group, an aryloxy group, an aralkyl group, an ethynyl group, and a halogen group are preferable. R ₄ is not limited to these substituents. Moreover, these substituents may further have a substituent.

Next, the carboxylate ion in Formula (5) is divided into a case where it does not have X ₁ which is a divalent linking group (n = 0) and a case where it has (n = 1). Furthermore, when having X ₁ is a divalent linking group (n = 1), X ₁ is a case of having a carbonyl group, are divided into two types of case no. For this reason, the carboxylate ion in Formula (5) is further represented by Formula (5-1) having no carbonyl group and Formula (5-2) having a carbonyl group. The europium complex may have any of complex structures having these carboxylate ions as ligands.
^{_{R 4 -R 6 -COO - (5-1}} )
_{R 4 - (CO) - (} R 6) m -COO - (5-2)

In the formula (5-1) and the formula (5-2), R ₆ may be any divalent linking group, and for example, a divalent linking derived from an alkylene group or a ring-assembled hydrocarbon. And a divalent linking group derived from a group, an aliphatic ring, an aromatic ring, or a heterocyclic ring. In Formula (5-2), m is 0 or 1. Examples of the alkylene group for R ₆ include methylene and ethylene. Examples of the ring assembly hydrocarbon include biphenyl, terphenyl, binaphthyl, cyclohexylbenzene, and phenylnaphthalene. Examples of the aliphatic ring include cyclopentane, cyclohexane, cycloheptane, norbornane, bicyclohexyl and the like. Examples of the aromatic ring include the same compounds as the specific examples of the aromatic ring described above. Examples of the heterocyclic ring include aliphatic heterocyclic rings such as pyrazoline, piperazine, imidazolidine, and morpholine in addition to the aromatic heterocyclic ring described above. Other examples include thioalkylene such as —SCH ₂ —; oxyalkylene such as —OCH ₂ —; vinylene (—C═C—) and the like. R ₆ is not limited to these divalent substituents. Moreover, these divalent substituents may further have a substituent.

  Specific examples of the carboxylic acid from which the carboxylic acid ion in formula (5) is derived are illustrated below, but the present invention is not limited thereto. The following carboxylic acid (1-10) is mentioned as a compound in case n is 0 in Formula (5).

In the formula (5), when n is 1 and X is R ₆ (formula (5-1)), the following carboxylic acids (11 to 15) may be mentioned.

  In the formula (5-2), examples of the compound when m is 0 include the following carboxylic acids (16, 17).

In the formula (5-2), the following carboxylic acids (18 to 30) are exemplified as a compound in which m is 1 and R ₄ is a phenyl group and R ₆ is a phenyl group.

In the formula (5-2), the following carboxylic acids (31 to 34) may be mentioned as a compound when m is 1 and R ₄ is a phenyl group and R ₆ is a naphthyl group.

In the formula (5-2), when m is 1, R ₄ is a phenyl group, and R ₆ is another group, the following carboxylic acids (35 to 37) are exemplified.

In the formula (5-2), the following carboxylic acids (38 to 41) may be mentioned as a compound when m is 1 and R ₄ is a naphthyl group and R ₆ is an aromatic ring.

In the formula (5-2), examples of the compound in which m is 1 and R ₄ is a naphthyl group and R ₆ is another group include the following carboxylic acids (42 to 44).

In the formula (5-2), examples of the compound in which m is 1 and R ₄ is an acenaphthyl group, R ₆ is a phenyl group or the like include the following carboxylic acids (45 to 48).

In the formula (5-2), the following carboxylic acids (49 to 55) may be mentioned as compounds in which m is 1 and R ₄ is a fluorenyl group and R ₆ is a phenyl group.

In the formula (5-2), examples of the compound in which m is 1 and R ₄ is a phenanthrenyl group, R ₆ is a phenyl group or the like include the following carboxylic acids (56 to 59).

In the formula (5-2), when m is 1, R ₄ is a heterocyclic group, and R ₆ is a phenyl group, the compound has the following carboxylic acid (60, 61, I-1 to I— 21).

  The carboxylic acid from which the carboxylate ion as the ligand in formula (5) is derived can be synthesized by a known synthesis method. Regarding the synthesis method, for example, New Experimental Chemistry Course Vol. 14 “Synthesis and Reaction of Organic Compounds (II)”, page 921 (1977), edited by The Chemical Society of Japan, or 4th edition Experimental Chemistry Course Volume 22 “Organic Synthesis”. IV ", page 1 (1992) edited by the Chemical Society of Japan. Typical examples of the synthesis method include oxidation reaction of the corresponding primary alcohol or aldehyde, hydrolysis reaction of ester or nitrile, Friedel-Crafts reaction with acid anhydride, and the like.

In particular, cyclic anhydrides of dicarboxylic acids such as phthalic anhydride, naphthalic anhydride, succinic anhydride, diphenic anhydride, 1,2-cyclohexanedicarboxylic anhydride, 2,3-pyridazine dicarboxylic anhydride were used. In the Friedel-Crafts reaction, a carboxylic acid having a carbonyl group in the molecule can be synthesized. For example, according to the Friedel-Crafts reaction using an aromatic hydrocarbon or aromatic heterocycle and phthalic anhydride, a carboxylic acid having a carbonyl group bonded to the ortho position of the benzene ring is represented by the following reaction formula. Easy to synthesize. A carboxylic acid having a carbonyl group bonded to the ortho position of the benzene ring is preferable because a complex having higher luminance than that of the para-substituted product can be easily obtained. In the formula, Ar represents an aromatic hydrocarbon or an aromatic heterocyclic ring.

Examples of the auxiliary ligand (R ₅ ) composed of the Lewis base in Formula (5) include the same compounds as the auxiliary ligand (R ₂ ) composed of the Lewis base in Formula (3) described above.

  The following can be illustrated as a europium complex which coordinated such carboxylic acid.

In the present invention, as the blue phosphor and the green phosphor used together with the europium complex which is a red fluorescent complex, known phosphors can be used in addition to the above-described fluorescent complexes. Examples of such phosphors include inorganic phosphors such as ZnS: Ag, Sr ₅ (PO ₄ ) ₃ Cl: Eu, BaMgAl ₁₀ O ₁₇ : Eu as blue phosphors. In addition, examples of the green phosphor include inorganic phosphors such as ZnS: Cu, ZnS: CuAl, BaMgAl ₁₀ O ₁₇ : Eu, Mn.
In order to emit white light, these phosphors may be used in combination.

The LED (light emitting diode) used in the present invention is a near-ultraviolet LED, and the emission peak wavelength is preferably in the range of 360 nm to 470 nm, and particularly preferably has a peak wavelength in the range of 380 nm to 470 nm. In particular, it is preferable to use an LED having an emission peak wavelength of 405 ± 10 nm.
If the peak wavelength is excessively short, organic compounds such as complexes are likely to be photodegraded. If the peak wavelength is excessively long, photoexcitation energy necessary for the emission of the fluorescent complex can be obtained. Therefore, the phosphor cannot emit light.

A metal cap 4 was attached to the stem 2 on which a near ultraviolet LED GU35S400T (center wavelength: 400 nm) manufactured by Showa Denko KK was mounted.
The metal cap 4 was made of Kovar as a material. This has an inner diameter of 1.8 mm, an outer diameter of 2.0 mm, and a length of 5.0 mm. Further, a glass 6 of aluminoborosilicate glass (borosilicate glass BFK) manufactured by Nippon Electric Glass Co., Ltd. having a diameter of 1.6 mm and a thickness of 0.5 mm is fused and bonded to the top surface. The sealing temperature was 950 ° C. On the inner peripheral surface and the top surface, in the atmosphere in nitrogen, the aforementioned europium complex compound 1-1 [in the formula (1), X = H, Y = CF ₃ , Y = H, p = 2, q = 3 The above-mentioned combination was dispersed in a silicate resin and applied, and the metal cap 4 was filled with FC-3283 (manufactured by 3M) as an inert liquid 9. For solder plating on the outer peripheral surface of the stem 2, SnCu-based Cu 2.5% solder plating, which is Sn-based solder, is used, and the stem 2 is press-fitted into the metal cap 4 at room temperature at a predetermined pressure to be hermetically sealed. (See FIGS. 2 and 3).
Airtightness was checked with red liquid. After 6 hours of immersion in this solution, the appearance was judged by visual inspection. As a result, it turned out that it is excellent in airtightness.
As a result, red light emission with high color reproducibility was observed. Moreover, since it filled with the inert liquid, it was confirmed that the temperature rise can be suppressed. It was also confirmed that the light extraction efficiency was improved.

In Example 1, except that the inert liquid was changed to FC-40 (manufactured by 3M), the light emitting device was assembled in the same manner and evaluated in the same manner, and the same result as in Example 1 was obtained.

In Examples 1 and 2, as pastes to be injected, BaMgAl ₁₀ O ₁₇ : Eu (blue phosphor), ZnS: Cu (green phosphor), and the same europium complex compound 1-1 (red phosphor) as in Example 1 A light emitting device was assembled in the same manner as in Examples 1 and 2 except that the above mixture was dispersed in polyvinyl alcohol, and white light emission with high color reproducibility was observed.

In Examples 1 to 3, when the same operation was performed except that the europium complex (red phosphor) was changed to the above-described various exemplary compounds, similarly good results were obtained.

A light emitting device capable of realizing a white LED, particularly a white LED with little color variation is obtained.

It is a front view which shows the structure of embodiment of a light-emitting device. It is a block diagram for demonstrating the manufacturing method of a light-emitting device. It is a block diagram for demonstrating the manufacturing method of a light-emitting device. It is a block diagram for demonstrating the manufacturing method of other embodiment of a light-emitting device.

Explanation of symbols

1 Light-Emitting Element 10 Light-Emitting Device 2 Stem 3 Lead 4 Metal Cap 5 Solder 6 Glass 61 Spherical Glass Lens 7 Organic Phosphor 8 Wire 9 Inert Liquid

Claims (14)

A cylindrical stem with at least two insulated lead wires, a light emitting element, a light emitting transparent member on the top surface of the stem, and an organic fluorescent light on the inner surface And a metal cap filled with an inert liquid for cooling. The light emitting element is mounted on the stem, and the stem is press-fitted into the metal cap. A light-emitting device, wherein the body is hermetically sealed. The light-emitting device according to claim 1, wherein the light-emitting element is a near-ultraviolet LED that emits near-ultraviolet light.   The light-emitting device according to claim 1, wherein the transparent member is a glass plate or a glass lens.   The light emitting device according to claim 1, wherein the organic phosphor is applied and hermetically sealed to at least a part of the top surface and / or the inner peripheral surface of the metal cap. The light emitting device according to any one of claims 1 to 4, wherein a metal cushioning material serving as a cushioning material when the metal cap is press-fitted is provided on an outer peripheral portion of the stem.   6. The light emitting device according to claim 5, wherein the metal cushioning material is a soft metal plating film. The light emitting device according to claim 6, wherein the metal buffer material is a plating film of a solder material.   The light emitting device according to claim 7, wherein the solder material is formed of a SnCu alloy. The light-emitting device according to claim 1, wherein the organic phosphor is a red phosphor complex. The light-emitting device according to claim 9, wherein the red phosphor complex is an Eu diketone or a carboxylic acid complex. The light-emitting device according to claim 1, further using a blue and / or green phosphor in addition to the organic phosphor. The light-emitting device according to claim 1, wherein the inert liquid has a thermal conductivity of 0.01 to 0.1 W / mK. The light-emitting device according to claim 12, wherein the inert liquid is a fluorine-based or hydrocarbon-based compound. A light emitting element is mounted on a cylindrical stem with at least two insulated leads, and a transparent member for light emission is integrated on the top surface of the metal cap. In an atmosphere, an organic phosphor is applied, and an inert liquid for cooling is filled. A solder material is applied to an outer peripheral portion of the stem, which is a joint portion between the stem and the metal cap. A method for manufacturing a light emitting device, wherein the organic phosphor is hermetically sealed by press-fitting into the metal cap at room temperature.

Images