JP2006073748A - Light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting device which has a first emitter emitting light ranging from near-ultraviolet rays to visual light, and a second emitter containing an organic fluorescent material that emits light when radiated with the light from the first emitter, suppresses the photodeterioration of the second emitter using a sealing material, and the deterioration of the organic fluorescent material and the sealing material therefor caused by a color change and a long time of service, produces no lighting dot, and provides the light emission of a long life. <P>SOLUTION: The light-emitting device has the first emitter emitting light ranging from near-ultraviolet rays to visual light, and the second emitter containing the organic fluorescent material that emits light when radiated with the light from the first emitter. In the light-emitting device, the second emitter is sealed with the sealing material via a shielding layer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light-emitting device, and more particularly, a light-emitting device that converts light of a semiconductor light-emitting element or the like with an organic phosphor, and suppresses discoloration, deterioration with time, and the like of the organic phosphor and its sealing material. The present invention relates to a light-emitting device that can emit light with a long lifetime without light emission spots.

  Compared with fluorescent lamps, which are typical examples of conventional light emitting devices, light emitting devices that convert the color of light from semiconductor light emitting elements such as mercury lamps, light emitting diodes (LEDs), and laser diodes (LDs) with phosphors are blue, It is noted that by mixing red and green light, light of various colors such as white can be developed without spots and with good color rendering and in a wide color reproduction range. In particular, LEDs and LD have high luminous efficiency. Also, there is an advantage that no harmful mercury is used, and therefore, a light emitting device in which an LED or LD and a phosphor are combined has been actively developed and put into practical use in lighting or the like.

However, since the emission wavelength of LEDs and LDs is longer than 360 nm, red inorganic phosphors such as yttrium oxide europium complexes (Y ₂ O ₃ : Eu) used in fluorescent lamps and the like have sufficient light emission. Therefore, it is not possible to obtain a high-luminance light-emitting device. On the other hand, in order to generate high-luminance red light, europium is used as a phosphor that efficiently absorbs and emits light in the near ultraviolet to visible region. As the (Eu) complex has attracted attention, a light emitting device in which an organic phosphor such as an Eu complex having a β-diketone anion as a ligand and an LED or LD is combined has been proposed (for example, Patent Documents). 1, see Patent Document 2.). However, an Eu complex having an anion of β-diketone as a ligand is easily photodegraded and has not yet been put into practical use as a light emitting device requiring durability.

On the other hand, in the same way that the LED, LD, etc. are sealed with a sealing material, such as an epoxy resin, to suppress light deterioration, etc. In order to prevent light deterioration due to light, it is also known to seal an organic phosphor with a sealing material such as an epoxy resin (see, for example, Patent Document 3). However, according to the study by the present inventors, when the organic phosphor is sealed with an epoxy resin or the like, the organic phosphor and the epoxy resin are discolored or deteriorated with time, and light emission spots are generated or the lifetime is reduced. It turns out that there is a problem. In addition, although development of LED of 360 nm or less and LD light is also actively conducted, since the light energy becomes larger as the wavelength becomes shorter, the phosphor and its sealing material are significantly deteriorated. Practical application is difficult.
JP2003-81986. US Pat. No. 6,366,033. Special table 2000-509912 gazette.

  The present invention has been made in view of the above-described current situation, and includes a first illuminant that generates light in the near ultraviolet to visible region, such as an LED and an LD, and light irradiation from the first illuminant. In a light-emitting device including a second light-emitting body containing an organic phosphor that emits light, light degradation of the second light-emitting body is suppressed by the sealing material, and the organic phosphor and the sealing material thereof It is an object of the present invention to provide a light emitting device that can suppress discoloration, deterioration with time, etc., and can emit light with a long lifetime without light emission spots.

  The present invention includes a first illuminant that generates light in the near ultraviolet to visible region, and a second illuminant that contains an organic phosphor that emits light when irradiated with light from the first illuminant. The gist of the light-emitting device is that the second light-emitting body is sealed with a sealing material through a shielding layer.

  According to the present invention, a first illuminant that generates light in the near ultraviolet to visible region, and a second illuminant that contains an organic phosphor that emits light when irradiated with light from the first illuminant. In the light-emitting device provided, the sealing material suppresses the light deterioration of the second light-emitting body, and the organic phosphor and the sealing material are prevented from being discolored, deteriorated over time, and have a long lifetime without light emission spots. It is possible to provide a light emitting device that can emit light.

  In the light emitting device of the present invention, the first light emitter is not particularly limited as long as it emits light in the near ultraviolet region having a wavelength of 360 to 410 nm, but emits light having a peak wavelength in the wavelength region. Preferred examples are semiconductor light emitting devices such as light emitting diodes (LEDs) and laser diodes (LDs), and LD is particularly preferred from the viewpoint of power consumption.

  Among these semiconductor light emitting devices, the light emission output and the external quantum efficiency are remarkably large, and by combining with a second light emitter described later, very bright light emission can be obtained with low power, so gallium nitride (GaN) LED and LD using a compound compound semiconductor are preferable. For example, the GaN-based compound semiconductor has a light emission intensity of 100 times or more with respect to a current load of 20 mA, as compared with a semiconductor using a silicon carbide (SiC) -based compound semiconductor that generates light in the same region.

Furthermore, the GaN-based LED or LD is, Al _X Ga _Y N luminous layer, GaN luminous layer or In _X Ga _Y N which has a light-emitting layer. Among them, among the GaN-based LEDs, those having an In _x Ga _y N light emitting layer are particularly preferable because the light emission intensity is very strong. In addition, in the GaN-based LED, those in which the light emitting layer is doped with Zn or Si or those without a dopant are preferable for adjusting the light emission characteristics. A GaN-based LED has these light-emitting layer, p-layer, n-layer, electrode, and substrate as basic components, and the light-emitting layer is composed of n-type and p-type Al _x Ga _y N layers, GaN layers, or In Those having a heterostructure sandwiched between _X Ga _Y N layers and the like are preferable because of high light emission efficiency, and those having a heterostructure in a quantum well structure are more preferable because of higher light emission efficiency. In addition, in the GaN-based LD, a multiple quantum well structure of an In _x Ga _y N layer and a GaN layer is particularly preferable because the emission intensity is very strong. In the above, the value of X + Y is usually in the range of 0.8 to 1.2.

  In the light-emitting device of the present invention, the first light-emitting body is usually configured by being sealed with a sealing material such as an epoxy resin in order to block it from the outside air.

  The second light emitter that efficiently absorbs and emits light from the excitation light source of the first light emitter contains an organic phosphor, usually in the form of particles of the organic phosphor, or The organic phosphor particles are dispersed in a binder resin.

  Here, the organic phosphor in the present invention is preferably a rare earth ion complex, and the rare earth element in the rare earth ion complex is cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm). , Europium (Eu), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and the like. Europium (Eu), which is a red phosphor that emits light with high brightness when irradiated with near ultraviolet light, is preferably used.

  The rare earth ion complex is preferably a rare earth ion complex having an anion having an aromatic ring as a ligand, and the anion ligand having the aromatic ring has a substituent containing an aromatic ring. An anion derived from a β-diketone anion and an anion derived from a carboxylic acid having a substituent containing an aromatic ring is particularly preferred.

As a complex having a β-diketone anion having a substituent containing an aromatic ring as a ligand, which is particularly preferable as a rare earth ion complex, for example, the following general formulas (1), (2), and (3) The europium complex represented by either of these is mentioned.
(R ¹ ) ₃ Eu (1)
(R ¹ ) ₃ Eu (R ² ) ₂ (2)
[(R ¹ ) ₄ Eu] ^- (R ³ ) ⁺ (3)
[In the formulas (1), (2), and (3), R ¹ represents an anion of β-diketone having a substituent containing an aromatic ring, R ² represents an auxiliary ligand composed of a Lewis base, (R ³ ) ⁺ represents a quaternary ammonium ion. ]

As the aromatic ring in the β-diketone having a substituent containing an aromatic ring as R ¹ in the general formulas (1), (2), and (3), in addition to the aromatic hydrocarbon compound, An aromatic heterocyclic compound, a heterocyclic condensed aromatic hydrocarbon compound, and the like are included, and at least one of these aromatic rings may be included, and the aromatic ring may have a substituent. . Examples of the aromatic hydrocarbon compound include benzene, naphthalene, and phenanthrene. Examples of the aromatic heterocyclic compound include heterocycles containing oxygen, sulfur, and nitrogen atoms such as furan, thiophene, pyrazoline, and pyridine. Examples of the ring compound and the heterocyclic condensed aromatic hydrocarbon compound include carbazole, dibenzofuran, dibenzothiophene, and the like.

  Examples of the substituent of these aromatic rings include alkyl groups such as methyl, ethyl, propyl and butyl; fluoroalkyl groups such as trifluoromethyl and pentafluoromethyl; alkoxy groups such as methoxy and ethoxy; benzyl, Aralkyl groups such as phenethyl; aryloxy groups such as phenoxy, naphthoxy and biphenyloxy; hydroxyl groups; allyl groups; acyl groups such as acetyl and propionyl; acyloxy groups such as acetoxy, propionyloxy and benzoyloxy; methoxycarbonyl, ethoxycarbonyl and the like Alkoxycarbonyl group; aryloxycarbonyl group such as phenoxycarbonyl; carboxyl group; carbamoyl group; amino group; dimethylamino, diethylamino, methylbenzylamino, diphenylamino, acetylme Substituted amino groups such as ruamino; substituted thio groups such as methylthio, ethylthio, phenylthio and benzylthio; mercapto groups; substituted sulfonyl groups such as ethylsulfonyl and phenylsulfonyl; cyano groups; halogen groups such as fluoro, chloro, bromo and iodo; Can be mentioned. These substituents may be bonded to each other to form a ring.

In addition, as the substituent other than the aromatic ring in the β-diketone having a substituent containing an aromatic ring as R ¹ in the general formulas (1), (2), and (3), the aromatic Examples thereof include the same substituents as those mentioned for the substituent of the group ring (however, the halogen group is excluded).

Specific examples of β-diketone having a substituent containing an aromatic ring as R ¹ in the general formulas (1), (2), and (3) are shown below. Note that the present embodiment is not limited to these.

  Furthermore, specific examples of the europium complex represented by the general formula (1) are shown below. Note that the present embodiment is not limited to these.

In addition, the auxiliary ligand comprising a Lewis base as R ² in the general formula (2) is not particularly limited, but is usually a Lewis base compound having a nitrogen atom or an oxygen atom that can be coordinated to a europium ion. Selected from. Examples thereof include amines which may have a substituent, also amine oxides, phosphine oxides, and sulfoxides. Two Lewis base compounds 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 amine oxides include pyridine-N-oxide. N-oxide of the amine such as 2,2′-bipyridine-N, N′-dioxide and the like, and as the phosphine oxide, triphenylphosphine oxide, trimethylphosphine oxide, trioctylphosphine oxide, etc. Examples of the sulfoxide include diphenyl sulfoxide and dioctyl sulfoxide. Of these Lewis base compounds, two compounds such as bipyridine and phenanthroline that have two coordinated atoms in the molecule, for example, a nitrogen atom, are provided with two Lewis base compounds. You may make it function like a ligand. Moreover, as these substituents, the same substituents as mentioned as the substituents of the aromatic ring in the general formula (1) can be mentioned. Of 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 of the Lewis base compound as an auxiliary ligand composed of a Lewis base as R ² in the general formula (2) are shown below. Note that the present embodiment is not limited to these.

  Furthermore, specific examples of the europium complex represented by the general formula (2) are shown below. Note that the present embodiment is not limited to these.

Examples of the ammonium ion as R ³ in the general formula (3) include quaternary ammonium salts derived from alkylamines, arylamines, aralkylamines, and the like. Examples thereof 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; aralkyl groups such as benzyl and phenethyl groups.

  Specific examples of the europium complex represented by the general formula (3) are shown below. Note that the present embodiment is not limited to these.

Further, as a complex having an anion derived from a carboxylic acid having a substituent containing an aromatic ring, which is particularly preferable as a rare earth ion complex, for example, europium represented by the following general formula (4) A complex.
[R ⁴ - (X) _n -COO] _{^{3 Eu (R 5) 2 (}} 4)
[In the formula (4), R ⁴ represents a monovalent group containing an aromatic ring, X represents a divalent linking group, n is 0 or 1, and R ⁵ is an auxiliary group comprising a Lewis base. Indicates the quantifier. ]

  The ligand represented by the general formula (4) has an aromatic ring, has 8 or more π electrons, and has a carboxylate ion constituting a π electron conjugated system as a ligand. This is preferable from the viewpoint of the wavelength range. The number of aromatic monocycles is not particularly limited as long as the triplet energy of the carboxylate ion base compound is higher than the europium ion excited state energy level, but it is usually 3 or less. preferable. When the number of aromatic monocycles is 4 or more, for example, a compound such as pyrene having four benzene rings is excited by absorbing light from the first light emitter such as a semiconductor light emitting device. There is a possibility that the energy is lowered and the europium complex does not emit light.

The monovalent group containing an aromatic ring as R ⁴ in the general formula (4) preferably has 3 or less aromatic monocycles. Examples of the aromatic ring include aromatic monocyclic hydrocarbon compounds such as benzene, naphthalene, indene, biphenylene, acenaphthene, fluorene, phenanthrene, tetralin, and indane, and aromatic condensed polycyclic hydrocarbon compounds, benzoquinone, naphthoquinone, and the like. , Derivatives from aromatic hydrocarbon compounds such as anthraquinone, aromatic monocyclic heterocyclic compounds such as furan, pyrrole, thiophene, oxazole, isoxazole, thiazole, imidazole, pyridine, triazine, benzofuran, benzothiophene, coumarin, benzopyran, Heterocyclic fused aromatic hydrocarbon compounds such as carbazole, xanthene, and quinoline.

  In addition, these aromatic rings may have a substituent. Examples of the substituent include alkyl groups such as methyl, ethyl, propyl and butyl; fluoroalkyl groups such as trifluoromethyl and pentafluoroethyl. A cycloalkyl group such as a cyclohexyl group; an ethynyl group; an arylethynyl group such as phenylethynyl, pyridylethynyl and thienylethynyl; an alkoxy group such as methoxy and ethoxy; an aryl group such as phenyl and naphthyl; an aralkyl group such as benzyl and phenethyl; Aryloxy groups such as phenoxy, naphthoxy and biphenyloxy; hydroxyl groups; allyl groups; acyl groups such as acetyl, propionyl, benzoyl, toluoyl and biphenylcarbonyl; acyloxy groups such as acetoxy, propionyloxy and benzoyloxy; Alkoxycarbonyl groups such as carbonyl and ethoxycarbonyl; aryloxycarbonyl groups such as phenoxycarbonyl; carboxyl groups; carbamoyl groups; amino groups; substituted amino groups such as dimethylamino, diethylamino, methylbenzylamino, diphenylamino, acetylmethylamino; Substituted thio groups such as ethylthio, phenylthio and benzylthio; mercapto groups; substituted sulfonyl groups such as ethylsulfonyl and phenylsulfonyl groups; cyano groups; and halogen groups such as fluoro, chloro, bromo and iodo. May further have a substituent. Among these, an alkyl group, an alkoxy group, an aryl group, a cycloalkyl group, an aryloxy group, an aralkyl group, an ethynyl group, and a halogen group are preferable.

  In addition, the carboxylate ion in the general formula (4) is classified into a case where it does not have X which is a divalent linking group (n = 0) and a case where it has (n = 1). When it has X as a linking group (n = 1), X is classified into two types, that is, when it has a carbonyl group and when it does not. Therefore, the carboxylate ion in the general formula (4) is further represented by the following general formula (5) having no carbonyl group and the following general formula (6) 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)
R ⁴ —CO— (R ⁶ ) _m —COO ⁻ (6)
[In formulas (5) and (6), R ⁴ is the same as in formula (4), R ⁶ represents a divalent linking group, and m is 0 or 1. ]

Examples of the divalent linking group as R ⁶ in the general formulas (5) and (6) include, for example, alkylene groups such as methylene and ethylene, and ring assembly carbonization such as biphenyl, terphenyl, binaphthyl, cyclohexylbenzene, and phenylnaphthalene. Divalent group derived from a hydrogen compound, divalent group derived from an alicyclic hydrocarbon compound such as cyclopentane, cyclohexane, cycloheptane, norbornane, bicyclohexyl, etc., the same as the specific examples of the aromatic ring described above A divalent group derived from the above compound, a divalent group derived from an aliphatic heterocyclic compound such as pyrazolidine, piperazine, imidazolidine and morpholine, a thioalkylene group such as —SCH ₂ —, and an oxy such as —OCH ₂ —. An alkylene group, a vinylene group, and the like, and these divalent linking groups have a substituent. It may be.

  Specific examples of the carboxylic acid from which the carboxylate ion in the general formula (4) is derived are shown below. It should be noted that the present embodiment is not limited to these.

  Examples of the carboxylic acid when n is 0 in the general formula (4) include the following compounds.

Moreover, the following compounds are mentioned as carboxylic acid represented by the said General formula (5) in case n is 1 in the said General formula (4), and X is R < ⁶ >.

  In the general formula (6), examples of the carboxylic acid when m is 0 include the following compounds.

  In the general formula (6), examples of the carboxylic acid when m is 1 include the following compounds.

  In the present invention, the carboxylic acid from which the carboxylate ion as the ligand in the general formula (4) is derived is, for example, New Experimental Chemistry Course Vol. 14, “Synthesis and Reaction of Organic Compounds (II)”, page 921. (1977) The Chemical Society of Japan, 4th edition, Experimental Chemistry Course Vol. 22, “Organic Synthesis IV”, page 1 (1992) The Chemical Society of Japan, etc. 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 compound, an aromatic heterocyclic compound or a heterocyclic condensed aromatic hydrocarbon compound and phthalic anhydride, as shown in the following reaction formula, A carboxylic acid having a carbonyl group bonded to the ortho position can be easily synthesized. A carboxylic acid having a carbonyl group bonded to the ortho position of the benzene ring is preferable because a complex having a higher luminance than that of the para-substituted product is easily obtained. In the formula, ArH represents an aromatic hydrocarbon compound, an aromatic heterocyclic compound or a heterocyclic condensed aromatic hydrocarbon compound.

In addition, as an auxiliary ligand which consists of a Lewis base as R < ⁵ > in the said General formula (4), the same compound as quoted as R < ² > in the said General formula (2) is mentioned.

  The second phosphor in the present invention includes, as the organic phosphor, only the rare earth ion complex, the rare earth ion complex and an organic phosphor other than the rare earth ion complex, and the organic phosphor. Also suitable are those containing the rare earth ion complex and further containing an inorganic phosphor.

  In the light emitting device of the present invention, the first light emitter described above is preferably a surface emitting type in that the light emitting efficiency of the entire light emitting device can be improved. The surface-emitting type has strong light emission in the surface direction. For example, in the surface-emitting GaN-based LD, the crystal growth of the light-emitting layer and the like is controlled, and the edge of the light-emitting layer is devised. Light emission in the plane direction can be made stronger than the direction. By making the first light emitter a surface light emitting type, the light emission cross-sectional area per unit light emission amount can be increased as compared with the type emitting light from the edge of the light emitting layer. As a result, the second light emitter irradiated with the light is Since the irradiation area can be increased with the same amount of light and the irradiation efficiency can be increased, stronger light emission can be generated.

  In addition, when the first light emitter is of a surface emission type, the second light emitter is preferably a film. As a result, the light from the surface-emitting type first light emitter has a sufficiently large cross-sectional area. Therefore, when the second light-emitting body is in the form of a film in the direction of the cross section, the irradiation cross-sectional area to the light-emitting substance is Since it becomes large per unit quantity, the intensity | strength of light emission from a luminescent substance can be enlarged more. In the case where the second light emitter is in the form of a film, it is preferable that the second light emitter in the form of a film is in direct contact with the light emitting surface of the first light emitter. Contact here refers to a state in which the first light emitter and the second light emitter are in direct contact with no gap. As a result, it is possible to avoid a light amount loss in which light from the first light emitter is reflected by the film surface of the second light emitter and oozes out, so that the light emission efficiency of the entire apparatus can be improved.

  When the second illuminant is in the form of a film as described above, the second illuminant is usually configured in a form in which the particles of the organic phosphor are dispersed in a binder resin, and has a shape other than the film form. May be similarly configured. In the case of the form dispersed in the binder resin, the content and the film thickness of the organic phosphor in the binder resin are determined as an amount capable of efficiently wavelength-converting the light from the first light emitter. In particular, when white light is used, it is determined by blending adjustment in order to obtain white light having a specified color temperature and a balance with emission intensity of other phosphors such as a green phosphor and a blue phosphor.

  As the binder resin, for example, vinyl alcohol resins such as polyvinyl alcohol; vinyl acetal resins such as polyvinyl formal and polyvinyl butyral; polymethyl (meth) acrylate, polyethyl (meth) acrylate, polyvinyl Acrylate resins such as (meth) acrylate; Styrene resins such as polystyrene; Polyester resins; Polyamide resins; Polyamideimide resins; Polycarbonate resins; Vinyl chloride resins such as polyvinyl chloride; Chlorides such as polyvinylidene chloride Vinylidene resins; olefin resins such as polyethylene and polypropylene; thermoplastic resins such as cellulose resins such as ethyl cellulose and nitrocellulose; and phenol resins; unsaturated polyester resins Silicone resin; urethane resin; polyimide resin; heat or / and photo-curing resin such as alkyd resin, polyfunctional acrylate-containing resin, etc. Among them, polyvinyl alcohol with good transparency, heat resistance, light fastness, etc. Polyvinyl butyral and the like are preferable.

  Further, in the light emitting device of the present invention, the second light emitter is sealed with a sealing material in the same manner as the first light emitter is sealed with the sealing material. Examples of the material include the same resins as those mentioned as the binder resin in the second luminous body. Among them, epoxy resins, silicon resins, polyfunctional acrylate-containing resins, etc. are used in terms of transparency, light fastness, and the like. An epoxy resin is preferable, and an epoxy resin is particularly preferable. Here, the sealing material for the second light emitter is dispersed in the form of organic phosphor particles in the first light emitter sealing material or particles in which the organic phosphor is dispersed in the binder resin. The form with which the sealing material of the 1st light-emitting body used as the sealing material of the 2nd light-emitting body, such as a formed form, may be sufficient.

  In the light emitting device of the present invention, the second light emitting body sealed with the sealing material as described above is provided with a shielding layer in order to eliminate direct contact between the second light emitting body and the sealing material. It is essential to be sealed with a sealing material. When this shielding layer is not interposed, discoloration of the sealing material due to contact with the organic phosphor in the second light emitter or decomposition of the organic phosphor in the second light emitter due to contact with the sealing material or the like It becomes difficult to suppress such alterations. In the present invention, the shielding layer is provided for the purpose of avoiding such discoloration or alteration due to direct contact between the second light emitter and the sealing material, and therefore naturally. In addition, the shielding layer itself should not cause deterioration of the organic phosphor in the second luminous body, discoloration of the sealing material, etc. Therefore, the material used for the shielding layer is at least the second emission. It is necessary that the organic phosphor and the sealing material in the body do not cause a chemical change.

  The material of the blocking layer is not particularly limited as long as it does not cause a chemical change in the organic phosphor and the sealing material in the second light emitter, and is exemplified as a binder resin in the second light emitter. Among them, the organic resin species and the binder resin species in the second light emitter, and the resin species constituting the sealing material are selected. From the standpoints of preparation of the coating liquid at the time of layer formation and easiness of the coating operation, a liquid resin or a resin having excellent solvent solubility is preferable. For example, a water-soluble resin such as a vinyl alcohol resin or a vinyl acetal resin. Particularly preferred are organic solvent-soluble resins such as, and cured products of heat- and / or photo-curable solventless liquid resins such as silicon resins and polyfunctional acrylate-containing resins. In addition, when the second phosphor is configured in a form in which an organic phosphor is dispersed in a binder resin, the shielding layer is the same or the same type as the binder resin in terms of compatibility with the binder resin. It is preferable to use a resin.

  Further, the film thickness of the shielding layer may be a thickness that can prevent alteration or the like due to the organic phosphor in the second luminous body coming into contact with the sealing material, and specifically, about 5 to 500 μm. It is preferable that it is about 10-200 micrometers.

  In addition, in order to improve the durability of the organic phosphor in the second light emitter, particularly the light fastness, a known antioxidant is added to the binder resin in the second light emitter as necessary. It may be. Further, an ultraviolet absorber may be added to the shielding layer or the sealing material as necessary. Examples of the ultraviolet absorber include benzophenone series such as o-hydroxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2- (2′-hydroxyphenyl) benzotriazole, 2 -(2'-hydroxy-5'-t-octylphenyl) benzotriazole, 2- (2'-hydroxy-3'-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2 Benzotriazoles such as' -hydroxy-5'-methylphenyl) benzotriazole, cyanoacrylates such as ethyl-2-cyano-3,3-diphenyl acrylate, 5-ethylhexyl-2-cyano-3,3-diphenyl acrylate , Phenylsulcylate, 4-t-butylphenylsa Salicylic acids such as tyrate, succinic anilides such as 2-ethyl-5′-t-butyl-2′-ethoxy-N, N′-diphenyloxalamide, zinc oxide, titanium oxide, zirconium oxide, etc. Examples of the inorganic oxide system are shown below.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist.

Example 1
An Eu (TTA) ₃ Phen complex having the following structure as an organic phosphor is 0.5% by weight in a 20% by weight methyl ethyl ketone solution of polyvinyl butyral resin (“S-Rec BL-1” manufactured by Sekisui Chemical Co., Ltd.) as a binder resin. Then, 0.04 g of this solution was applied to a circular slide glass having a diameter of 15 mm and a height of 2 mm and dried at 50 ° C. for 1 hour. Further, the same polyvinyl butyral resin solution was applied thereon and dried in the same manner to form a shielding layer having a thickness of about 50 μm. Furthermore, 0.4 g of an epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd., “YX8000” + “MH7000” 10: 9 mixture) 0.4 g is applied, precured at 100 ° C. for 3 hours, and further at 150 ° C. for 1 hour. A second phosphor sample was prepared by heat-curing to form a sealing material layer. The epoxy resin of the formed sealing material layer was only slightly yellowing. Moreover, when the luminescent property was evaluated about the obtained sample by using GaN-type LD as a 1st light-emitting body, it was confirmed that it shows favorable fluorescence. Furthermore, after irradiating light from the ultraviolet region to the visible region for 40 hours using a light resistance tester (“Ci4000” manufactured by Atlas Co., Ltd.), the fluorescence of the phosphor was visually observed. Almost no decrease in light emission was observed.

Example 2
A polyvinyl alcohol resin (“GOHSENOL GL-3” manufactured by Nippon Gosei Kogyo Co., Ltd.) was used as the binder resin, and the same organic phosphor as used in Example 1 was dispersed in the 20 wt% aqueous solution so as to be 5 wt%. A second phosphor sample was prepared in the same manner as in Example 1 except that the shielding layer was also formed of the same polyvinyl alcohol resin. The epoxy resin of the formed sealing material layer was such that slight yellowing was observed. Moreover, when the obtained sample was evaluated for luminescent property in the same manner as in Example 1, it was confirmed that the sample showed good fluorescent luminescent property. Furthermore, after irradiating light from the ultraviolet region to the visible region, the luminescent property of the phosphor was visually observed, and almost no decrease in luminescent property was observed compared to before the irradiation.

Example 3
An Eu (TTA) ₃ (TPPO) ₂ complex having the following structure was used as the organic phosphor, and a polyvinyl alcohol resin (“GOHSENOL GL-3” manufactured by Nippon Gosei Kogyo Co., Ltd.) was used as the binder resin. A second phosphor sample was produced in the same manner as in Example 1 except that the organic phosphor was dispersed so as to be 5% by weight and that the shielding layer was also formed of the same polyvinyl alcohol resin. The formed epoxy resin of the sealing material layer had almost no discoloration. Moreover, when the obtained sample was evaluated for luminescent property in the same manner as in Example 1, it was confirmed that the sample showed good fluorescent luminescent property. Furthermore, after irradiating light from the ultraviolet region to the visible region, the luminescent property of the phosphor was visually observed, and almost no decrease in luminescent property was observed compared to before the irradiation.

Example 4
The Eu (TTA) ₃ (TPPO) ₂ complex having the above structure was used as the organic phosphor, and a polyvinyl alcohol resin (“GOHSENOL GL-3” manufactured by Nippon Gosei Kogyo Co., Ltd.) was used as the binder resin. The organic phosphor was dispersed so as to be 5% by weight, and a thermosetting silicone resin (“KE1031” manufactured by Shin-Etsu Chemical Co., Ltd.) was used as a shielding layer, and 0.07 g thereof was applied, and at 80 ° C. for 2 hours. A second phosphor sample was prepared in the same manner as in Example 1 except that the second phosphor sample was cured. The formed epoxy resin of the sealing material layer had almost no discoloration. Moreover, when the obtained sample was evaluated for luminescent property in the same manner as in Example 1, it was confirmed that the sample showed good fluorescent luminescent property. Furthermore, after irradiating light from the ultraviolet region to the visible region, the luminescent property of the phosphor was visually observed, and almost no decrease in luminescent property was observed compared to before the irradiation.

Example 5
The Eu (TTA) ₃ (TPPO) ₂ complex having the above structure was used as the organic phosphor, and a polyvinyl alcohol resin (“GOHSENOL GL-3” manufactured by Nippon Gosei Kogyo Co., Ltd.) was used as the binder resin. The organic phosphor was dispersed so as to be 5% by weight, and an ultraviolet curable acrylic resin (1 g of dimethylol tricyclodecane diacrylate was added as a shielding layer to an initiator “DAROCUR TPO manufactured by Ciba Specialty Chemicals Co., Ltd.) A second phosphor sample was prepared in the same manner as in Example 1 except that 0.07 g of the resin solution was added and cured by irradiation with ultraviolet rays. The formed epoxy resin of the sealing material layer had almost no discoloration. Moreover, when the obtained sample was evaluated for luminescent property in the same manner as in Example 1, it was confirmed that the sample showed good fluorescent luminescent property. Furthermore, after irradiating light from the ultraviolet region to the visible region, the luminescent property of the phosphor was visually observed, and almost no decrease in luminescent property was observed compared to before the irradiation.

Comparative Example 1
A second phosphor sample was produced in the same manner as in Example 1 except that the shielding layer was not formed. The formed epoxy resin of the sealing material layer was remarkably discolored to yellowish brown. Further, when the obtained sample was evaluated for luminescent properties in the same manner as in Example 1, the fluorescent luminescent property was significantly inferior to that of Example 1.

Comparative Example 2
A second phosphor sample was produced in the same manner as in Example 2 except that the shielding layer was not formed. The epoxy resin of the formed sealing material layer was discolored yellow. Further, when the obtained sample was evaluated for luminescent properties in the same manner as in Example 1, the fluorescent luminescent property was considerably inferior to that of Example 2.

Comparative Example 3
A second phosphor sample was prepared in the same manner as in Example 3 except that the shielding layer was not formed. The epoxy resin of the formed sealing material layer was discolored yellow. Further, when the obtained sample was evaluated for luminescent properties in the same manner as in Example 1, the fluorescent luminescent property was considerably inferior to that of Example 3.

Comparative Example 4
A second phosphor sample was produced in the same manner as in Example 1 except that the shielding layer was not formed and the sealing material layer was not formed. The obtained sample was irradiated with light from the ultraviolet region to the visible region in the same manner as in Example 1, and then the light emission property of the phosphor was visually observed. As a result, no light emission was observed.

Claims (9)

In a light emitting device including a first light emitter that generates light in the near ultraviolet to visible region, and a second light emitter containing an organic phosphor that emits light when irradiated with light from the first light emitter, A light-emitting device, wherein the second light-emitting body is sealed with a sealing material through a shielding layer. The shielding layer in the second luminous body is formed of any resin selected from the group consisting of a vinyl alcohol resin, a vinyl acetal resin, and a curable liquid resin cured product. The light-emitting device of description. The light emitting device according to claim 1 or 2, wherein the organic phosphor contained in the second light emitter is a rare earth ion complex. The light-emitting device according to claim 3, wherein the rare earth ion complex is a rare earth ion complex having an anion having an aromatic ring as a ligand. The rare earth ion complex is a rare earth ion complex having a β-diketone anion having a substituent containing an aromatic ring or an anion derived from a carboxylic acid having a substituent containing an aromatic ring as a ligand. The light emitting device according to claim 3 or 4. The light-emitting device according to claim 3, wherein the rare earth ion complex has a Lewis base as an auxiliary ligand. The light emitting device according to claim 2, wherein the rare earth ion complex is a europium complex. The light emitting device according to claim 1, wherein the first light emitter is a laser diode or a light emitting diode. The light emitting device according to any one of claims 1 to 8, wherein the second luminous body contains a rare earth ion complex and another phosphor.