JP2014086526A - Light-emitting diode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-emitting diode excellent in sealing performance, heat resistance, light extraction efficiency, emission luminance, and the like.SOLUTION: The light-emitting diode including a die bond, a light-emitting element, and a sealing layer is characterized in that: the sealing layer comprises an organic resin and zirconia fine particles surface-treated with an organosilicon compound; the surface-treated zirconia fine particles have an average secondary particle diameter (D) in the range of 5-50 nm and an average primary particle diameter (D) in the range of 5-50 nm; and the ratio (D)/(D) of the average secondary particle diameter (D) to the average primary particle diameter (D) is in the range of 1-10.

Description

  The present invention relates to a light emitting diode excellent in sealing performance, heat resistance, light extraction efficiency, light emission luminance, and the like.

  Conventionally, in a light emitting diode (LED), in order to protect the semiconductor element, the semiconductor element is sealed with a transparent sealing agent such as an epoxy resin or a silicone resin. However, there is a problem that energy emitted from the LED increases as the wavelength of the LED becomes shorter and the luminance increases, and in some cases, heat is stored and the sealing resin is yellowed to lower the luminance of the LED.

In addition, since the refractive index of the encapsulant is low, there is a problem that light emitted from the LED is reflected by the encapsulating layer and the light transmittance is lowered, and energy efficiency is lowered.
For this reason, a composition in which surface-modified zirconia particles having a particle diameter of 1 to 20 nm are blended with a silicone resin as a sealant that has excellent thermal stability, improved refractive index, and improved light transmittance is proposed. Has been. (Patent Document 1: JP 2009-173757 A)

  However, in order to improve the dispersibility of zirconia particles in silicone resin, primary surface modification and secondary surface modification are necessary, and in order to eliminate residual OH group, tertiary surface modification with alkylsilazane surface treatment agent is necessary. Therefore, in addition to low productivity, a large amount of surface modifier is required, and these surface treatment agents have a refractive index of around 1.4. In addition, the refractive index of the cured resin (sealing material) using this is not necessarily high, and thus there has been a limit to improving the light transmittance.

  In addition to the large number of surface treatment agents used, it is expensive, which is disadvantageous in terms of economy. Further, in this case, since the adhesion between the light emitting element and the sealing material is low, reflection of light is amplified at the interface between the light emitting element and the sealing material, and the light extraction efficiency may not be sufficiently improved. .

  On the other hand, it is disclosed that a silica layer in which a light-emitting element is covered with silica glass containing a sol-gel phosphor is provided to suppress deterioration of the phosphor due to moisture. (Patent Document 2: Japanese Patent Laid-Open No. 2002-203989)

  In addition, a silicone resin is used as a sealing material for sealing the light emitting element (LED chip), and metal parts such as a lead frame and a reflective layer are covered with a light-transmitting inorganic material such as sol-gel glass, so that light extraction efficiency and durability are achieved. Is disclosed. (Patent Document 3: Japanese Patent Application Laid-Open No. 2007-324256)

  As described above, it is well known that surface treatment with an organosilicon compound (silane coupling agent) is used to improve the dispersibility in the resin, and the applicant of the present invention modifies the surface with a trialkylsilyl group. It has been proposed to use oxidized zirconium particles. (Patent Document 4: JP2012-121941A)

  In this case, zirconium oxide fine particles are first surface-treated with a tetrafunctional organosilicon compound, then solvent-substituted with an organic solvent, an organosilicon compound (2) having a trialkylsilyl group is added, and heated to react with the particles. To be trialkylated.

JP 2009-173757 A Japanese Patent Laid-Open No. 2002-203989 JP 2007-324256 A JP 2012-121941 A

  However, even if the yellowing of the resin can be suppressed, the refractive index of the sol-gel layer is as low as about 1.4 to 1.5, and the deviation from the refractive index of the light emitting element is large. The problem is that the light extraction efficiency of the LED device is poor. In addition, although the adhesion at the interface between the light-emitting element and the sol-gel glass layer is high, the adhesion at the interface between the sol-gel glass layer and the resin layer cannot be improved. The transmittance could not be improved, but rather decreased.

  As a result of intensive studies in view of such problems, the present inventors have determined that the sealing layer of the light-emitting element is made of zirconia fine particles surface-treated with a resin and an organosilicon compound, and is identified as the surface-treated zirconia fine particles. By using a material satisfying the particle size relationship, the adhesiveness of the resin layer is improved, the light emission efficiency and the light emission luminance are improved, and the yellowing of the resin can be suppressed, thereby completing the present invention. It was.

  Although the surface treatment of the zirconia fine particles is known per se, the modified zirconia fine particles subjected to the conventionally known surface treatment have insufficient dispersibility in the sealing resin used in the light emitting diode. As a result, the sealing performance, heat resistance, light extraction efficiency, light emission luminance and the like may not always be high.

  Therefore, the present inventors focused on the average primary particle diameter and average secondary particle diameter of the surface-treated zirconia fine particles as the ease of dispersion of the modified zirconia fine particles, and when these are in a specific relationship, It has been found that the characteristics as a light emitting diode can be improved by being easily dispersed in the sealing resin.

The configuration of the present invention is as set forth in the claims.
[1] In a light emitting diode comprising a die bond, a light emitting element, and a sealing layer,
The sealing layer is composed of organic resin and zirconia fine particles surface-treated with an organosilicon compound, and the average secondary particle diameter (D _M2 ) of the surface-treated zirconia fine particles is in the range of 5 to 50 nm, and the average primary particles The diameter (D _M1 ) is in the range of 5 to 50 nm, and the ratio of the average secondary particle diameter (D _M2 ) to the average primary particle diameter (D _M1 ) (D _M2 ) / (D _M1 ) is in the range of 1 to 10 A light emitting diode characterized by that.
[2] The organosilicon compound is an organosilicon compound represented by the following formula (1), and the content of the organosilicon compound in the surface-treated zirconia fine particles is R _n —SiO 2 _{(4-n) / 2} The light-emitting diode according to [1], wherein the half-width of the main peak of the ²⁹ Si MAS NMR spectrum of the surface-treated zirconia fine particles is in the range of 3 to 15 ppm.
_{R n -SiX 4-n (1} )
(In the formula, R is an unsubstituted or substituted hydrocarbon group having 1 to 10 carbon atoms, and may be the same or different from each other. X: an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, Halogen, hydrogen, n: an integer of 1 to 3)

[3] The light emission according to [1] or [2], wherein a high refractive index metal oxide fine particle layer having a refractive index in a range of 1.5 to 2.5 is provided between the light emitting element and the sealing layer. diode.
[4] The light emitting diode according to [3], wherein an average thickness of the high refractive index metal oxide fine particle layer is in a range of 20 to 300 nm.
[5] The light emitting diode according to [4], wherein the high refractive index metal oxide fine particle layer has a surface roughness (Ra) in the range of 1 to 25 nm.
[6] The light emitting diode according to [3], wherein an average particle diameter of the high refractive index metal oxide fine particles is in the range of 3 to 50 nm.
[7] The light-emitting diode according to [3], wherein the high refractive index metal oxide fine particle layer further contains a binder together with the high refractive index metal oxide fine particles.
[8] The light-emitting diode according to [7], wherein the binder is a hydrolyzed polycondensate of a hydrolyzable metal compound.
[9] The light emitting diode according to [7], wherein the content of the binder is in the range of 5 to 40% by weight as a solid content in the high refractive index metal oxide fine particle layer.
[10] The light emitting diode according to [1], wherein a refractive index of the sealing layer is lower than a refractive index of the high refractive index metal oxide fine particle layer.
[11] The light-emitting diode according to [1] to [10], wherein the organic resin is an epoxy resin or a silicone resin.

  According to the present invention, it is possible to provide a light emitting diode having excellent sealing performance, high light transmittance, and excellent light emission luminance, light emission efficiency, and the like. Furthermore, it provides a light-emitting diode that has excellent light-emitting brightness, light-emitting efficiency, etc., with high adhesion between the light-emitting element and the sealing resin layer, suppression of peeling, low heat storage, suppression of yellowing of the sealing material, etc. can do.

The schematic diagram of the one aspect | mode of the light emitting diode which concerns on this invention is shown.

Hereinafter, first, the light emitting diode according to the present invention will be described.
[Light emitting diode]
The light-emitting diode according to the present invention is a light-emitting diode comprising a die bond, a light-emitting element, and a sealing layer, the sealing layer comprising zirconia fine particles surface-treated with a resin and an organosilicon compound, and the surface-treated zirconia fine particles The average secondary particle size (D _M2 ) is in the range of 5 to 50 nm, the average primary particle size (D _M1 ) is in the range of 5 to 50 nm, the average secondary particle size (D _M2 ) and the average primary particle size the ratio of the _{(D M1) (D M2)} / (D M1) is characterized by a range of 1-10.

FIG. 1 shows one embodiment of a light emitting diode according to the present invention. In FIG. 1, a sealing layer containing zirconia fine particles surface-treated with an organosilicon compound is formed on the surface of the light emitting element. In FIG. 1, a high refractive index metal oxide fine particle layer is provided between the light emitting element and the sealing layer (the high refractive index metal oxide fine particle layer is optional).
As the die bond and the light emitting element, a die bond and a light emitting element used in a conventionally known light emitting diode are used.

Sealing <br/> light emitting diode according to the present invention, on the light emitting element, the sealing layer is provided. The sealing layer is usually made of an organic resin, and a resin such as an epoxy resin, a silicone resin, or an acrylic resin is used. In the present invention, an epoxy resin or a silicone resin is preferably used.

Examples of the epoxy resin include resins marketed as bisphenol A, phenol novolac, and the like, and mixtures thereof.
When an epoxy resin is used, a sealing layer having a relatively high refractive index can be formed, and a sealing layer having excellent light transmittance and sealing performance can be formed. On the other hand, the yellowing may not be suppressed.

Examples of the silicone resin include dimethyl silicone resin, phenyl silicone resin, methyl phenyl silicone resin, modified silicone resin, and mixtures thereof.
When a silicone resin is used, there is no yellowing and a light emitting diode excellent in sealing performance and the like can be obtained. On the other hand, the refractive index may be relatively low and the light transmittance may be insufficient.

(Surface treatment zirconia fine particles)
The sealing layer contains zirconia fine particles surface-treated with an organosilicon compound represented by the following formula (1).
_{R n -SiX 4-n (1} )
(In the formula, R is an unsubstituted or substituted hydrocarbon group having 1 to 10 carbon atoms, and may be the same or different from each other. X: an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, Halogen, hydrogen, n: an integer of 1 to 3)

Thus, by using a 1-3 functional organosilicon compound, it is possible to obtain zirconia fine particles having excellent dispersibility in a resin.
Examples of organosilicon compounds include methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, isobutyltrimethoxysilane, vinyl Trimethoxysilane, vinyltriethoxysilane, vinyltris (βmethoxyethoxy) silane, 3,3,3-trifluoropropyltrimethoxysilane, methyl-3,3,3-trifluoropropyldimethoxysilane, β- (3,4 -Epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxymethyltrimethoxysilane, γ-glycidoxymethyltriethoxysilane, γ-glycidoxyethyltrimethoxysilane, γ-glycidoxyethyltriethoxy Silane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ- (β-glycidoxyethoxy) propyltrimethoxysilane, γ- (meth) acrylooxymethyltrimethoxysilane, γ- (meth) acrylooxymethyltriethoxysilane, γ- (meth) acrylooxyethyltrimethoxysilane, γ- (meth) acryloxyethyltriethoxysilane, γ- (meth) acrylooxypropyltrimethoxy Silane, γ- (meth) acrylooxypropyltriethoxysilane, butyltrimethoxysilane, isobutyltriethoxysilane, hexyltriethoxysilaoctyltriethoxysilane, decyltriethoxysilane, butyltriethoxysilane, isobutyltriethoxysilane, hexyl Triethoxy Lan, octyltriethoxysilane, decyltriethoxysilane, 3-ureidoisopropylpropyltriethoxysilane, perfluorooctylethyltrimethoxysilane, perfluorooctylethyltriethoxysilane, perfluorooctylethyltriisopropoxysilane, trifluoropropyltri Examples include methoxysilane, γ-mercaptopropyltrimethoxysilane, trimethylsilanol, methyltrichlorosilane, and the like, and mixtures thereof.

  Among them, γ- (meth) acrylooxymethyltrimethoxysilane, γ- (meth) acrylooxymethyltrioxysilane, γ- (meth) acrylooxyethyltrimethoxysilane, γ- (meth) acrylooxy Acrylic or methacrylic silane coupling agents such as ethyltriethoxysilane, γ- (meth) acryloxypropyltrimethoxysilane, and γ- (meth) acryloxypropyltriethoxysilane are dispersed in the resin. Since zirconia fine particles having excellent properties and the like are obtained, they can be suitably used.

The content of the organosilicon compound in the zirconia fine particles surface-treated with the organosilicon compound varies depending on the particle diameter of the zirconia fine particles, the type of the organosilicon compound, etc., but R _n -SiO _{(4-n) / 2} (n Is an integer of 1 to 3), preferably 1 to 100% by weight, more preferably 2 to 50% by weight.

  When the content of the organosilicon compound is small, aggregated zirconia fine particles may be obtained, and dispersibility in an organic resin or the like is low, and even when dispersed, a uniformly monodispersed dispersion may not be obtained. . For this reason, even if the sealing layer is formed using zirconia fine particles, sealing performance, light transmittance (light emission efficiency), and the like may be insufficient.

  Even if the content of the organosilicon compound is too large, the organosilicon compound effectively bonded to the surface of the zirconia fine particles does not increase, and the effect of further improving the dispersibility in the organic resin is not exhibited. Since the amount of the compound itself increases, for example, an unreacted organosilicon compound, a reaction product between the organosilicon compounds increases, and the effect of further improving the dispersibility of the obtained zirconia fine particles in the organic resin may not be obtained. As a result, the refractive index decreases, the light transmittance of the sealing layer may be insufficient, and the light emission efficiency (luminance) of the LED may decrease.

The zirconia fine particles surface-treated with the organosilicon compound used in the present invention preferably have a full width at half maximum of ²⁹ Si MAS NMR spectrum in the range of 3 to 15 ppm, more preferably 3.5 to 12 ppm.

In the ²⁹ Si MAS NMR spectrum of zirconia fine particles, usually two or more peaks having different chemical shift values derived from Si of the organosilicon compound are measured. The main peak is the peak having the highest peak height. I mean. Depending on the conditions, one peak may be measured.

  When the half width at the main peak is less than 3 ppm, there is no significant difference from the zirconia fine particles modified by hydrolyzing the organosilicon compound (silane coupling agent) in the conventional dispersion, and the obtained zirconia fine particles aggregate. In some cases, dispersibility in an organic resin may be insufficient, and sealing performance, light transmittance (light emission efficiency), and the like may be insufficient.

In the zirconia fine particles used in the present invention, the silicon atoms of the organosilicon compound are close to each other on the surface of the particles and widen the ²⁹ Si MAS NMR spectrum width, that is, close to the extent that affects the nuclear spin of the silicon atoms. It is presumed that the surface-treated zirconia fine particles obtained by the conventional surface treatment method have a relatively small interaction on the surface of the organosilicon compound particles.

In the present invention, it is preferable to use a powder of surface-treated zirconia fine particles obtained by a method for producing zirconia fine particles surface-treated with an organosilicon compound described later.
The surface-treated zirconia fine particle powder has good dispersibility in the encapsulant resin and does not contain an organic solvent, so there is no need to remove the organic solvent by drying or the like, which causes voids or poor curing. There is nothing.

The surface-treated zirconia fine particles preferably have an average secondary particle diameter (D _M2 ) in the range of 5 to 50 nm, more preferably 8 to 40 nm.
When the average secondary particle size (D _M2 ) of the surface-treated zirconia fine particles is smaller than this range, it is difficult to obtain the surface-treated zirconium oxide fine particles having excellent dispersibility, and the average secondary particle size (D _M2) ) Is too large, the sealing layer may have insufficient transparency and light transmittance may be insufficient.

The surface-treated zirconia fine particles preferably have an average primary particle diameter (D _M1 ) of 5 to 50 nm, more preferably 8 to 40.
If the surface-treated zirconia fine particles have an average primary particle diameter (D _M1 ) in the above range, a sealing layer having excellent dispersibility in a resin and excellent sealing performance, transparency, light transmittance, and the like can be obtained. .

In the above, the ratio (D _M2 ) / (D _M1 ) of the average secondary particle size (D _M2 ) to the average primary particle size (D _M1 ) is in the range of 1 to 10, more preferably 1 to 7. Is preferred.
The ratio (D _M2 ) / (D _M1 ) is usually not less than 1, and if it is too large, it indicates that the degree of aggregation of the surface-treated zirconia fine particles is high and dispersibility in the sealing resin becomes insufficient. In other words, it will remain as aggregated particles, and the sealing performance, transparency, light transmittance, etc. may be insufficient.

The average secondary particle diameter (D _M2 ) is adjusted by a dynamic scattering method using methanol as a dispersion medium, adjusted to a solid content concentration of 30% by weight, and ultrasonically dispersed.
The average primary particle size (D _M1 ) is determined by measuring the particle size of 100 particles by TEM observation and obtaining the average value.
Such a zirconia fine particle powder surface-treated with the organosilicon compound used in the present invention is produced as follows.

[Method for producing surface-treated zirconia fine particle powder]
The method for producing zirconia fine particle powder used in the present invention is characterized by comprising the following steps (a) to (c).
(A) Step for preparing water and / or organic solvent dispersion of zirconia fine particles (b) Step for adding organosilicon compound represented by formula (1) (c) Without adding hydrolysis catalyst for organosilicon compound Without solvent replacement
Drying process

Step (a)
A water and / or organic solvent dispersion of zirconia fine particles is prepared.
The average particle size (D _Z ) of the zirconia fine particles before the surface treatment is approximately 5 so that the average secondary particle size (D _M2 ) and the average primary particle size (D _M1 ) of the obtained surface-treated zirconia fine particles are in the above range. It is preferable to be in the range of ˜50 nm, preferably approximately 8 to 40 nm.

At this time, crystalline zirconia fine particles are preferably used as the zirconia fine particles.
Measurement of the average particle diameter (D _Z ) of the zirconia fine particles before the surface treatment is carried out by using water as a dispersion medium, adjusting the solid content concentration to 10% by weight, and evaluating ultrasonic dispersion using a dynamic scattering method.

(water)
The total amount of water can be used as the dispersion medium. However, when used in a mixture with an organic solvent, the amount of water used may be more than the amount capable of hydrolyzing the hydrolyzable group of the organosilicon compound to be used.

(Organic solvent)
The organic solvent is compatible with water and is not particularly limited as long as the organosilicon compound dissolves. However, methanol, ethanol, propanol, 2-propanol (IPA), butanol, diacetone alcohol, furfuryl alcohol, Alcohols such as tetrahydrofurfuryl alcohol, ethylene glycol, hexylene glycol, and isopropyl glycol; esters such as methyl acetate, ethyl acetate, and butyl acetate; diethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol Ethers such as monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether; acetone, Methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, ketones such as acetoacetate, methyl cellosolve, ethyl cellosolve, butyl cellosolve, toluene, cyclohexanone, isophorone and the like.

Among them, alcohols having a low boiling point can be suitably used because they can be dried and removed at a low temperature in the step (c) described later.
The concentration of the zirconia fine particles in water and / or the organic solvent dispersion is not particularly limited, but is preferably in the range of about 1 to 30% by weight as the solid content.
The dispersion is preferably subjected to a dispersion treatment. As a dispersion treatment method, a method such as sufficient stirring and irradiation with ultrasonic waves can be employed.

Step (b)
An organosilicon compound represented by the following formula (1) is added.
_{R n -SiX 4-n (1} )
(In the formula, R is an unsubstituted or substituted hydrocarbon group having 1 to 10 carbon atoms, and may be the same or different from each other. X: an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, Halogen, hydrogen, n: an integer of 1 to 3)

As the organosilicon compound, the aforementioned organosilicon compound is used.
In addition, when only water is used as the dispersion medium in the step (a) or when the organic solvent is small, it may be added as an organic solvent solution of the organosilicon compound in the present step (b).
The amount of the organosilicon compound in the surface-treated zirconia fine particles obtained is 1 to 100% by weight, where n is an integer of 1 to 3, and more preferably 2 to 50, as R _n —SiO 2 _{(4-n) / 2} (n is an integer of 1 to 3). It is preferable to add so that it may become the range of weight%.

  When the amount of the organosilicon compound used is small, aggregated zirconia fine particles may be obtained, and dispersibility in an organic resin or the like is low, and even when dispersed, a uniformly monodispersed dispersion may not be obtained. . For this reason, even if the sealing layer is formed using the surface-treated zirconia fine particles, the sealing performance, light transmittance (light emission efficiency), and the like may be insufficient.

  If the amount of the organosilicon compound used is too large, the organosilicon compound effectively bonded to the surface of the zirconia fine particles or the combination of the organosilicon compounds in the form of covering the surface of the zirconia fine particles will not increase, leading to an organic resin. In addition to the fact that the effect of further improving the dispersibility of the organic silicon compound is increased, the amount of the organic silicon compound itself increases, so that, for example, an unreacted organic silicon compound, the reaction product of the organic silicon compound increases, and the resulting zirconia fine particle organic resin In some cases, the effect of further improving the dispersibility in the light-emitting layer may not be obtained. In addition, the refractive index may be decreased, and the light transmittance of the sealing layer may be insufficient. May decrease.

Step (c)
Then dry. At this time, drying is performed without adding a hydrolysis catalyst for the organosilicon compound and without replacing the solvent. In the present invention, it is preferable to dry under reduced pressure or under flowing conditions. Although the reason is not clear, it is not necessary to add a catalyst for hydrolysis of an organosilicon compound, and it is not necessary to replace the solvent. When a catalyst is added or solvent substitution is performed, the stability of the dispersion may be lowered, or the dispersibility of the particles may be lowered.

  As a method of drying under flow, a rotary dryer such as a rotary evaporator is used. If the tumble dryer is used, the surface-treated zirconia fine particles will not be strongly agglomerated, and the surface-treated zirconia fine particle powder that is weakly agglomerated in a granular form can be obtained. System fine particle powder can be obtained.

  When dried under reduced pressure, the solvent can be removed at a lower temperature, and the surface-treated zirconia fine particles that can be easily monodispersed even if the zirconia fine particle surface OH groups and the organosilicon compound are bonded without agglomeration of the zirconia fine particles. Can be obtained.

  Here, “under reduced pressure” may be lower than normal pressure (atmospheric pressure). In the present invention, it is preferably about 800 hPa or less, more preferably 500 hPa or less. At this time, the pressure does not need to be constant, and the pressure can be gradually reduced.

  The drying temperature varies depending on the boiling point of the solvent, the drying method, and the like, but may be any temperature at which the solvent is volatilized, and is preferably 200 ° C or lower. More preferably, it is in the range of -30 to 150 ° C, more preferably 0 to 120 ° C.

  The drying method is not particularly limited as long as the surface-treated zirconia fine particles that can remove the water and / or the organic solvent, do not strongly aggregate, and have excellent dispersibility in the resin are obtained. A method such as spray drying can be employed.

  If the drying temperature is too high, the resulting surface-treated zirconia fine particles are strongly aggregated, resulting in insufficient dispersibility in the resin, resulting in insufficient sealing layer transparency and light transmittance. In some cases, the luminous efficiency (luminance) decreases.

The sealing layer may contain surface-treated metal oxide fine particles other than the surface-treated zirconia fine particles.
As the metal oxide fine particles, the refractive index of the sealing layer can be adjusted as necessary, and is not particularly limited as long as it has translucency. For example, SiO ₂ , TiO ₂ , Al ₂ O ₃ , ZnO, SnO ₂ , Sb ₂ O ₅ , In ₂ O ₃ , Nb ₂ O _{5 and} other metal oxide fine particles, mixed fine particles thereof, composite oxide fine particles, and mixtures thereof. Note that pure titanium oxide fine particles, particularly metal oxide fine particles having photocatalytic activity such as crystalline titanium oxide fine particles may accelerate yellowing depending on the resin used in the sealing resin layer. It is preferably used after being suppressed and deactivated. In particular, as low refractive index particles, silica-based hollow fine particles having cavities therein disclosed in Japanese Patent Application Laid-Open Nos. 2001-167737 and 2001-233611 filed by the present applicant are preferably used because of their low refractive index. be able to.

The surface treatment of the metal oxide fine particles can be performed in the same manner as the surface-treated zirconia fine particles.
The average secondary particle diameter (D _M2 ), average primary particle diameter (D _M1 ), and (D _M2 ) / (D _M1 ) ratio of the surface-treated zirconia fine particles obtained are preferably in the above ranges, When used in a sealing layer without aggregation, a light emitting device having excellent sealing performance, transparency, light transmittance, and luminous efficiency can be obtained.

  The refractive index of the surface-treated zirconia fine particles is preferably in the range of 1.58 to 2.0, more preferably 1.65 to 2.0. Those having a low refractive index may not be able to be prepared with a high refractive index of the sealing layer.

It is difficult to obtain a surface-treated zirconia fine particle having a refractive index exceeding 2.0.
In the present invention, the refractive index of the surface-treated zirconia fine particles is measured by the following method using Series M, B, A, AA, AAA made by CARGILL as a standard refractive liquid when the refractive index is approximately 1.70 or less. Measured with
(1) The surface-treated zirconia fine particle dispersion is taken in an evaporator and the dispersion medium is evaporated.
(2) This is dried at 80 ° C. for 12 hours to obtain a powder.
(3) A standard refraction liquid having a known refractive index is dropped on a glass plate of a few drops, and the above powder is mixed therewith.
(4) The operation of (3) is performed with various standard refractive liquids, and the refractive index of the standard refractive liquid when the mixed liquid becomes transparent is defined as the refractive index of the particles.

  When the refractive index is approximately 1.70 or more, the dispersion is concentrated or diluted to prepare a dispersion having a solid content concentration of 5 mass%, 10 mass%, 20 mass%, 30 mass%, or 40 mass%. Then, the specific gravity of the dispersion of each concentration can be measured with a buoyancy scale, and the liquid refractive index can be measured with a liquid refractometer (manufactured by ATAGO: RX-5000α), and the refractive index can be obtained by calculation.

(Composition of sealing layer)
The content of the surface-treated zirconium fine particles in the sealing layer is preferably in the range of 10 to 90% by mass, more preferably 20 to 85% by mass as the solid content (the rest is resin).

  If the content of the surface-treated zirconium fine particles in the sealing layer is small, the refractive index of the resin used becomes dominant, and the refractive index of each sealing layer is adjusted to a desired refractive index, or a seal having a desired refractive index. A stop layer may not be obtained.

  Even if the content of the surface-treated zirconium fine particles in the sealing layer is too large, the sealing layer itself may become hard and the stress relaxation effect inherent in the resin may not be sufficiently obtained. In addition, the particles become aggregated, which causes light scattering in the sealing layer, and the light transmittance is reduced, haze is increased, and luminous efficiency (luminance) is reduced. The sealing performance may be insufficient due to the small amount of resin.

In the present invention, other metal oxide fine particles may be blended in the sealing layer so as to adjust the refractive index within this range.
Adjustment of the refractive index of the sealing layer takes into account the refractive index of the resin, (1) changing the blending amount of the surface-treated zirconia fine particles having a high refractive index and a resin having a low refractive index, or (2) having a high refractive index. This is performed by changing the blending amount and blending ratio of the surface-treated zirconia fine particles and the metal oxide fine particles having a low refractive index, for example, surface-treated silica-based hollow particles. In order to obtain a sealing layer having a high refractive index, a large amount of surface-treated zirconia fine particles are blended, and in order to obtain a sealing layer having a low refractive index, the blending amount of the surface-treated silica-based hollow particles may be increased.

The refractive index of the sealing layer is preferably in the range of 1.52 to 1.90, more preferably 1.58 to 1.90.
If the refractive index is too low, light emitted from the light emitting element (LED) is reflected by the sealing material and the light transmittance is lowered, so that sufficient light emission efficiency (luminance) may not be obtained.

Moreover, it is difficult to obtain a high refractive index exceeding this range when the modified zirconia fine particles are used.
The thickness of the sealing layer varies depending on the configuration of the light emitting diode, but is preferably in the range of 0.05 to 20 mm, more preferably 0.1 to 10 mm. If the thickness of the sealing layer is thin, it is difficult to obtain the effect as the sealing layer. Even if the thickness of all the sealing layers is increased, the effect of improving the light transmittance is not greatly improved, and the economical efficiency is greatly reduced.

Such a sealing layer is formed by applying a composition containing the resin and surface-treated zirconium fine particles.
Such a sealing resin composition can be prepared by mixing the surface-treated zirconia fine particle powder obtained in the step (c) with a predetermined amount of a resin component. In addition, what does not contain a solvent for a resin component is desirable.

  In addition, a method in which a predetermined amount of a resin component is added to the organic solvent dispersion of the surface-treated zirconium fine particle powder, and then heated in a range where the resin does not cure, and the organic solvent is removed by heating under reduced pressure as necessary. Although it is possible, if the organic solvent remains in an amount of approximately 3% by weight or more, it may cause voids or poor curing.

The method for applying the sealing resin composition is not particularly limited as long as a sealing layer having a predetermined thickness can be formed with good adhesion to the surface of the light-emitting element or the high refractive index metal oxide fine particle layer described later. Examples include spin coating, bar coating, dipping, spraying, and potting.
In addition, when the resin composition for sealing does not contain a dispersion medium substantially, the drying after application | coating is unnecessary.

Next, the heat treatment is not particularly limited as long as the sealing layer can be formed by curing without altering the resin, and varies depending on the resin, for example, irradiation with an electron beam or approximately 100 to 200 ° C. Heat treatment with.
In the present invention, a high refractive index fine particle layer may be provided between the light emitting element and the sealing layer.

High Refractive Index Metal Oxide Fine Particle Layer In the light emitting diode according to the present invention, it is preferable that a high refractive index metal oxide fine particle layer is provided between the light emitting element and the sealing layer.

The refractive index of the high refractive index metal oxide fine particle layer is preferably 1.5 to 2.5, more preferably 1.8 to 2.5.
Such a high refractive index layer contains high refractive index metal oxide fine particles, and is a layer having a refractive index lower than the refractive index of the light emitting element and higher than the refractive index of the sealing layer. Examples of the metal oxide fine particles include metal oxide fine particles such as TiO ₂ , ZrO ₂ , Al ₂ O ₃ , ZnO, SnO ₂ , Sb ₂ O ₅ , In ₂ O ₃ , Nb ₂ O ₅ , and mixed fine particles thereof. , Composite oxide fine particles, and a mixture thereof. Among them, ZrO ₂ fine particles have a high refractive index and do not have photocatalytic activity, and therefore can be suitably used when using a resin that can yellow the sealing layer.

In the present invention, it is desirable to use modified zirconia particles for both the sealing layer and the high refractive index metal oxide fine particle layer.
Note that pure titanium oxide fine particles, particularly metal oxide fine particles having photocatalytic activity such as crystalline titanium oxide fine particles may accelerate yellowing depending on the resin used in the sealing resin layer. It is preferably used after being suppressed and deactivated.

  When the refractive index of the high refractive index metal oxide fine particle layer is in the above range, light emitted from the light emitting element can be efficiently passed through the sealing layer without being reflected. As a result, it is possible to obtain a light-emitting diode that has high light transmittance, low heat storage, and excellent light emission luminance and light emission efficiency.

The average particle diameter of the metal oxide fine particles is preferably in the range of 3 to 50 nm, more preferably 8 to 40 nm.
When the average particle diameter of the metal oxide fine particles is small, the metal oxide fine particles may aggregate to form a dense high refractive index metal oxide fine particle layer with good adhesion on the surface of the light emitting element. Although the aggregation is difficult even if the average particle diameter of the metal oxide fine particles is too large, a dense high refractive index metal oxide fine particle layer with good adhesion may not be formed on the surface of the light emitting device, and the light transmittance May decrease.

  The metal oxide fine particles can be used after surface treatment with a conventionally known silane coupling agent. As a coupling agent, the organosilicon compound as described in said Formula (1) can be used, Specifically, an above-described organosilicon compound is mentioned. When surface-treated metal oxide fine particles are used for the high refractive index metal oxide fine particle layer, the adhesion to the sealing layer can be further improved. As the surface treatment method, the above-described method for producing the surface-treated zirconia fine particle powder or a method based thereon can be employed.

  For the surface treatment of the metal oxide fine particles, a conventionally known silane coupling agent is used, a conventionally known method (a conventionally known silane coupling agent is added to the metal oxide dispersion, and an acid or alkali is added as necessary) The method of hydrolyzing with the addition of a hydrolysis catalyst can be employed, and the same method as that for the surface-treated zirconia fine particles described above can also be employed.

It is desirable that the high refractive index metal oxide fine particle layer further contains a binder.
The binder is not particularly limited as long as the metal oxide fine particles are bonded to each other, and a high refractive index metal oxide fine particle layer excellent in adhesion to a light emitting element, light transmittance, and the like is obtained. Matrix, sometimes referred to as a matrix).

In the present invention, a hydrolyzed polycondensate of a hydrolyzable metal compound is preferably used.
When the hydrolyzed polycondensate is contained, it has excellent adhesion to the light emitting element, light transmittance, and strength (hardness), and adhesion to the sealing layer formed on the high refractive index metal oxide fine particle layer. High refractive index metal oxide fine particle layer excellent in property (non-peelability) can be formed.

The hydrolyzable metal compound is preferably a hydrolyzable metal compound represented by the following formula (1).
R _n -MX _mn (1)
(Wherein, M is at least one metal element selected from Si, Ti, Zr and Al, and R is an unsubstituted or substituted hydrocarbon group having 1 to 10 carbon atoms, which may be the same as each other) X: alkoxy group having 1 to 4 carbon atoms, hydroxyl group, halogen, hydrogen, m: valence of element M, 3 or 4, n: integer of 0 to 2, and mn 2 or 3)

  As the hydrolyzable metal compound represented by the formula (1) used in the present invention, when the metal element M is specifically silicon, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, methyl Trimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, isobutyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxy Silane, vinyltris (βmethoxyethoxy) silane, 3,3,3-trifluoropropyltrimethoxysilane, methyl-3,3,3-trifluoropropyldimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltri Methoxysilane, γ-glycidoxymethyltrimethoxysilane, γ-glycidoxymethyltriethoxysilane, γ-glycidoxyethyltrimethoxysilane, γ-glycidoxyethyltriethoxysilane, γ-glycidoxypropyltri Methoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltriethoxysilane, γ- (β-glycidoxyethoxy) propyltrimethoxysilane, γ- (Meth) acrylooxymethyltrimethoxysilane, γ- (meth) acryloxymethyltriethoxysilane, γ- (meth) acryloxyethyltrimethoxysilane, γ- (meth) acrylooxyethyltriethoxysilane, γ- (meth) acrylooxypropyltrimethoxysilane, γ- (meth) acryl Rooxypropyltrimethoxysilane, γ- (meth) acrylooxypropyltriethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, butyltrimethoxysilane, isobutyltriethoxysilane, hexyltriethoxysilaoctyltriethoxy Silane, decyltriethoxysilane, butyltriethoxysilane, isobutyltriethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, decyltriethoxysilane, 3-ureidoisopropylpropyltriethoxysilane, perfluorooctylethyltrimethoxysilane, perfluorosilane Fluorooctylethyltriethoxysilane, perfluorooctylethyltriisopropoxysilane, trifluoropropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, trimethylsilanol, methyltrichlorosilane, etc. Is mentioned. Further, silicon tetrachloride, silane trichloride, disilicon hexachloride, and the like can also be suitably used. Furthermore, in addition to the compound of the above formula (1), an acidic silicic acid solution obtained by dealkalizing alkali silicate can also be suitably used.

  When the metal element is titanium, titanium tetraisopropoxide, titanium tetranormal butoxide, titanium tetra-2-ethylhexoside, titanium diisopropoxybisacetylacetonate, titanium tetraacetylacetonate, titanium dioctyloxybisoctylene glycolate, Examples include titanium diisopropoxybisethyl acetoacetate, polyhydroxytitanium stearate, titanium isopropoxyoctylene glycolate, tetrakis 2-ethylhexyloxytitanium, diisopropoxybisacetylacetonatotitanium, and the like. Moreover, titanium tetrachloride, titanyl sulfate, etc. can be used suitably.

  Further, when the metal element M is zirconium, zirconium tetraisopropoxide, zirconium tetranormal butoxide, zirconium tetra-2-ethylhexoside and the like can be mentioned. Moreover, tetrasalt zirconium, a zirconyl chloride, etc. can be used suitably.

  In addition, when the metal element M is aluminum, aluminum triisopropoxide, aluminum trinormal butoxide, aluminum tri-2-ethylhexoside, and the like can be given.

Moreover, aluminum chloride, aluminum sulfate, aluminum nitrate, etc. can be used suitably.
The content of the binder is preferably 60% by mass or less, more preferably 5 to 50% by mass as a solid content in the high refractive index metal oxide fine particle layer.

  If there are too many binders in the high refractive index metal oxide fine particle layer, it becomes a smooth surface and improves adhesion (non-peelability) with the sealing layer formed on the high refractive index metal oxide fine particle layer. The effect may not be obtained sufficiently.

In addition, it is preferable that the surface unevenness | corrugation of a high refractive index metal oxide fine particle layer exists in the range of 1-25 nm as surface roughness (Ra), Furthermore, 2-10 nm.
When the surface roughness (Ra) is small, the effect of improving the adhesiveness with the sealing layer provided on the high refractive index metal oxide fine particle layer is insufficient, and it easily peels and causes a decrease in light transmittance. There is a case. Even if the surface roughness (Ra) is too large, the adhesion with the sealing layer is not further improved, and the effect of suppressing peeling is not further improved. In some cases, the strength of the layer is reduced, or cracks are generated, causing a decrease in adhesion and a decrease in light transmittance.

  In the present invention, for the surface roughness (Ra), the arithmetic average roughness (Ra) is measured on the surface of the high refractive index layer using an atomic force microscope (Digitalscopes, Nanoscope-3a).

  The average thickness of the high refractive index metal oxide fine particle layer is preferably 20 to 300 nm, more preferably 50 to 200 nm. When the average thickness is thin, the light transmittance improvement and the adhesion improvement effect may not be sufficiently obtained. Even if the average thickness is too thick, cracks may occur in the high refractive index metal oxide fine particle layer, which may cause a decrease in adhesion and a decrease in light transmittance.

  Here, the average thickness of the high-refractive-index metal oxide fine particle layer is determined by peeling off at the drying stage when forming the high-refractive-index metal oxide fine particle layer, and then measuring the step on the surface of the hardened fine particle layer with a laser microscope (KEYENCE). : VK-8510).

Method for Forming High Refractive Metal Oxide Fine Particle Layer The high refractive index metal oxide fine particle layer can be formed by applying a dispersion of the metal oxide fine particles to the surface of the light emitting element, drying, and heat-treating. .

  The dispersion medium for the dispersion of the metal oxide fine particles is not particularly limited as long as the high refractive index metal oxide fine particles and the binder component used as required can be stably dispersed, and a conventionally known dispersion medium can be used.

  For example, alcohols such as water, methanol, ethanol, propanol, 2-propanol (IPA), butanol, diacetone alcohol, furfuryl alcohol, tetrahydrofurfuryl alcohol; methyl acetate, ethyl acetate, isopropyl acetate, isopropyl acetate, isobutyl acetate , Butyl acetate, isopentyl acetate, pentyl acetate, 3-methoxybutyl acetate, 2-ethylbutyl acetate, cyclohexyl acetate, esters such as ethylene glycol monoacetate, glycols such as ethylene glycol and hexylene glycol; diethyl ether, ethylene glycol monomethyl Ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol isopropyl ether, diethylene glycol Hydrophilic solvents including ethers such as nomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, and purpylene glycol ethyl ether, propyl acetate, isobutyl acetate, butyl acetate, isopentyl acetate, pentyl acetate, 3-methoxybutyl acetate Esters such as 2-ethylbutyl acetate, cyclohexyl acetate, and ethylene glycol acetate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, butyl methyl ketone, cyclohexanone, methyl cyclohexanone, dipropyl ketone, methyl pentyl ketone, and diisobutyl ketone; Examples include polar solvents such as toluene. These may be used singly or in combination of two or more.

  The dispersion of metal oxide fine particles may contain the binder (hydrolyzable metal compound, hydrolyzate thereof, hydrolyzed polycondensate, etc.). The concentration of the binder component in the dispersion is used so that the content in the resulting high refractive index metal oxide fine particle layer is in the above-described range as the solid content.

  The total solid content concentration of the metal oxide fine particle dispersion is preferably in the range of 0.5 to 20% by mass, more preferably 1 to 15% by mass. If it exists in this range, a fine particle layer with high adhesiveness can be formed by one coating.

  When the total solid content concentration of the metal oxide fine particle dispersion is small, the high refractive index metal oxide fine particle layer becomes too thin, and the effects of improving light transmittance and adhesion may not be sufficiently obtained. Moreover, the unevenness | corrugation of the surface of a high refractive index metal oxide fine particle layer may become too small, and the adhesion improvement effect may become inadequate. Even if the total solid content is too high, it is difficult to control the thickness of the metal oxide fine particle layer to 300 nm or less, and cracks are generated in the fine particle layer, which causes a decrease in adhesion and light transmittance. There is.

  The method for applying the metal oxide fine particle dispersion is not particularly limited as long as a high refractive index metal oxide fine particle layer having a predetermined thickness and surface roughness can be formed with good adhesion to the light emitting element surface. Method, bar coater method, dip method, spray method, potting method and the like.

The drying is not particularly limited as long as the dispersion medium can be substantially removed, and a conventionally known drying method can be employed.
Next, the heat treatment is not particularly limited as long as the high refractive index metal oxide fine particle layer can be cured without altering the light emitting element. For example, the heat treatment is generally performed at 100 to 500 ° C.

[Example]
EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited by these Examples.

[Example 1]
Preparation of surface-treated metal oxide fine particles (1) for forming a high refractive index layer 317.9 kg of zirconia hydroxide gel having a solid content concentration of 9.5% by mass was suspended in 535.3 kg of water to obtain a solid content concentration of 3. A 5 mass% zirconia hydroxide gel dispersion was prepared. Next, 354.9 kg of KOH aqueous solution having a concentration of 17% by mass, 302.0 kg of hydrogen peroxide aqueous solution having a concentration of 35% by mass, and 88.5 kg of an aqueous tartaric acid solution were added to the zirconia hydroxide gel dispersion having a solid content of 3.5% by mass. In addition, hydrothermal treatment was performed at 150 ° C. for 11 hours in an autoclave.

  After washing with an ultrafiltration membrane method until the electric conductivity becomes 0.2 mS / cm or less, it is subjected to a dispersion treatment with an ultrasonic homogenizer (manufactured by Nippon Seiki Seisakusho: US-600TCVP) to obtain a solid content of 11 A dispersion of 2% by mass of zirconia fine particles (1) was prepared. After adding 400 g of zirconia fine particles (1) dispersion and 11.2 g of γ-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-503) to a beaker and stirring for 5 minutes, the rotary evaporator The surface-treated metal oxide fine particle powder (1) was prepared by drying at 60 ° C. for 1.5 hours while gradually reducing the degree of vacuum until the pressure became 50 hPa or less.

  To 50 g of this surface-treated metal oxide fine particle powder (1), 114 g of propylene glycol monomethyl ether (PGME) was added and stirred, and 164 g of the surface-treated metal oxide fine particle (1) PGME dispersion having a solid content concentration of 30.5% by mass was obtained. Obtained.

The average particle diameter and refractive index of the surface-treated metal oxide fine particles (1) were measured, and the results are shown in the table.
The average particle diameter of the surface-treated metal oxide fine particles (1) is such that the solid content concentration of 30% by mass is obtained by adding PGME to the surface-treated metal oxide fine particles (1) PGME dispersion having a solid content concentration of 30.5% by mass. And measured with a particle size measuring device (ELS-Z, manufactured by Otsuka Electronics Co., Ltd.).

Preparation of binder (1) Modified alcohol (Solmix AP-11 manufactured by Nippon Alcohol Sales Co., Ltd .: Ethanol 85.5 wt%, Isopropyl alcohol 9.8 wt%, Methanol 4.7%) 58.8 g with tetramethoxysilane ( 17.6 g of M silicate 51) manufactured by Tama Chemical Industry Co., Ltd. was added, and 0.045 g of hydrochloric acid having a concentration of 36% by mass and 13.5 g of pure water were added. This was treated in an autoclave at 100 ° C. for 60 minutes to obtain a binder (1) comprising a tetramethoxysilane hydrolyzate having a solid concentration of 10.0% by mass.

Preparation of high refractive index metal oxide fine particles (1) dispersion liquid 32.85 g of the surface-treated metal oxide fine particles (1) PGME dispersion liquid having a solid content concentration of 30.5% by mass prepared above was modified with alcohol (Nippon Alcohol Sales). Co., Ltd. Solmix AP-11: ethanol 85.5% by mass, isopropyl alcohol 9.8% by mass, methanol 4.7% by mass) 316.13 g, PGME 67.27 g, binder (1) 33.75 g added Thus, a high refractive index metal oxide fine particle (1) dispersion having a solid content concentration of 3.0% by mass was prepared.

Preparation of a substrate with a high refractive index layer (1) A high refractive index metal oxide fine particle (1) dispersion liquid is a sapphire glass substrate (thickness: 0.43 mm, refractive index: 1.76, total light transmittance 82.0). %, Haze 0.0%) with a spin coater (500 rpm-120 seconds), heat treated at 80 ° C. for 30 seconds, and then cured by heat treatment at 150 ° C. for 30 minutes to obtain a high refractive index layer (1) A base material was prepared. The thickness of the high refractive index layer (1) was 100 nm.
The adhesion and surface roughness of the high refractive index layer (1) were measured by the following methods, and the results are shown in the table.

Adhesive high refractive index layer-coated substrate (1) The surface of the substrate with 11 parallel scratches at 1mm vertical and horizontal intervals using a knife to make 100 squares, and then the cellophane tape is adhered to and peeled off. The adhesion was evaluated by classifying the number of cells remaining without peeling into the following three stages.
Number of remaining cells: 100
Number of residual squares 90-99: △
Number of remaining squares: 89 or less: ×

Surface roughness high refractive index layer substrate with (1) the surface of an atomic force microscope (DigitalInstruments Co., Nanoscope-3a) of was used to measure the arithmetic mean roughness (Ra).

Refractive index The refractive index of the high refractive index layer (1) was separately measured by forming the high refractive index layer (1-2) by the following method. Instead of the sapphire glass substrate, a high refractive index metal oxide fine particle (1) dispersion was applied onto a silicon wafer and cured to form a high refractive index layer (1-2) having a thickness of 100 nm. Next, the refractive index of the high refractive index layer (1-2) was measured with an ellipsometer (manufactured by SOPRA: ESVG), and the results are shown in the table.

Preparation of surface-treated zirconia oxide fine particles (1) powder for sealing 317.9 kg of zirconia hydroxide gel having a solid content concentration of 9.5% by weight was suspended in 535.3 kg of water, and the solid content concentration of 3.5% by weight was suspended. A zirconia hydroxide gel dispersion was prepared.

Next, 354.9 kg of KOH aqueous solution of 17% by weight, 302.0 kg of hydrogen peroxide aqueous solution of 35% by weight, and tartaric acid of 10% by weight of the zirconia hydroxide gel dispersion having a solid content of 3.5% by weight. 88.5 kg of an aqueous solution was added, and the mixture was stirred at 30 ° C. for 2 hours with stirring to peptize the zirconia hydroxide gel. Step (a)

At this time, (M _OH ) / (M _Zr ) was 20, and (M _PO ) / (M _Zr ) was 10. Subsequently, 88.5 kg of a 10% by weight aqueous tartaric acid solution was added to the peptized zirconia hydroxide gel, and hydrothermally treated at 150 ° C. for 11 hours in an autoclave. Step (b)

Next, the zirconia fine particle dispersion was thoroughly washed by the ultrafiltration membrane method, and then dispersed with an ultrasonic homogenizer (manufactured by Nippon Seiki Seisakusho: US-600TCVP) to give a zirconia solid content of 11.2% by weight. A fine particle (1) dispersion was prepared. Step (c)

The average particle size (D _Z ) of the zirconia fine particles (1) was adjusted by adding water to a solid content concentration of 10% by weight, and measured with a particle size measuring device (ELS-Z, manufactured by Otsuka Electronics Co., Ltd.). The results are shown in Table 1.
Next, 400 g of the zirconia fine particle (1) dispersion was collected in a beaker. Subsequently, 400 g of methanol was added to prepare a zirconia-based fine particle (1) water / methanol dispersion having a solid content concentration of 5.6% by weight. Step (d)

At this time, the ratio of methanol in the water / methanol mixed dispersion medium is 56% by weight.
Next, zirconia fine particles (1) γ-methacrylooxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-503) as an organic silicon compound in a water / methanol dispersion, and organic in the surface-treated zirconia fine particles obtained. silicon compound was added 11.2g such that 15.3% by weight R ₁ -SiO _3/2, and stirred for 5 minutes. Step (e)

Next, while gradually reducing the degree of pressure reduction to 50 hPa or less with a rotary evaporator, drying was performed at 60 ° C. for 1.5 hours to prepare surface-treated zirconia fine particles (1) for sealing. Step (f)

The obtained surface-treated zirconia fine particles (1) for sealing were measured for average particle size (D _M2 ), average particle size (D _M1 ) and refractive index, and the results are shown in Table 1.

²⁹ Si MAS NMR spectra also sealing surface treated zirconia fine particles (1) Nuclear magnetic resonance apparatus ²⁹ Si MAS NMR spectrum for the powder (Agilent technologies Inc.: VNMRS-600) was used for the measurement. Polydimethylsilane (−34.44 ppm) was used as a standard substance, and measurement was performed by a single pulse method under conditions of a delay time of 15 seconds and a MAS speed of 6 kHz. This spectrum is shown in FIG. 3, and the chemical shift value and half width of the main peak analyzed by the curve fitting program attached to the apparatus are shown in the table.

Preparation of fat composition for sealing (1) Silicone resin (Ker-2500-A / KER-2500-B = 1/1 mixed solution manufactured by Shin-Etsu Chemical Co., Ltd.) 12.5 g and surface-treated zirconia fine particles for sealing (1) 25 g of powder was mixed to prepare a sealing resin composition (1).

Preparation of base material with sealing layer (1) Next, two glass plates having a thickness of 2 mm, a width of 2 cm and a length of 10 cm are formed on the base material with a high refractive index layer (1). Were fixed with a double-sided tape at an interval of 5 cm, and then the sealing resin composition (1) was dropped at the same interval, and the excess was removed using a 10 mm diameter stainless steel round bar. This was heat-treated at 100 ° C. for 1 hour, and further heat-treated at 150 ° C. for 5 hours to be cured, thereby preparing a substrate with a sealing layer (1). The thickness of the sealing layer at this time was 2 mm.

  The total light transmittance and haze of the obtained substrate (1) with a sealing layer were measured with a haze meter (NDH-300A manufactured by Nippon Denshoku Industries Co., Ltd.). Furthermore, the adhesion to the high refractive index layer and the refractive index of the sealing layer were evaluated by the following methods and evaluation criteria, and the results are shown in the table.

The surface of the substrate with the adhesive sealing layer (1) is made of 11 parallel scratches with a knife at intervals of 1 mm in length and width to make 100 squares, and the film when the cellophane tape is adhered and peeled to this is formed. The adhesion was evaluated by classifying the number of cells remaining without peeling into the following three stages (Table 1).
Number of remaining squares: ◎
Number of remaining squares 95 to 99: ○
Number of residual squares 90-94: △
Number of remaining squares: 89 or less: ×

Refractive index The refractive index of the sealing (resin) layer of the substrate with sealing layer (1) was measured by forming only the resin layer by the following method.

  Silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd., KER-2500-A / KER-2500-B = 1/1 mixture) is applied on a silicon wafer by the bar coater method (bar # 50), and after heat treatment at 100 ° C. for 1 hour Further, the resin was cured by heat treatment at 150 ° C. for 4 hours to form a resin layer having a thickness of 2 mm on the silicon wafer. Subsequently, the refractive index of the resin layer was measured with an ellipsometer (manufactured by SOPRA: ESVG), and the results are shown in the table.

[Example 2]
Preparation of surface-treated zirconia fine particle (2) powder for sealing In Example 1, a surface-treated zirconia fine particle (2) powder for sealing was prepared in the same manner as in Example 1 except that the drying temperature was 40 ° C.
For the obtained surface-treated zirconia fine particles (2) for sealing, the average particle diameter (D _M2 ), average particle diameter (D _M1 ), refractive index were measured, and ²⁹ Si MAS NMR spectrum was measured, and the result Are shown in Table 1.

Preparation of sealing fat composition (2) A sealing fat composition (2) was prepared in the same manner as in Example 1, except that the surface-treated zirconia fine particles (2) for sealing were used.
Preparation of base material with sealing layer (2) A base material with sealing layer (2) was prepared in the same manner as in Example 1 except that the fat composition for sealing (2) was used. The thickness of the resin sealing layer at this time was 2 mm.
The obtained base material with sealing layer (2) was evaluated for total light transmittance, haze, adhesion to the high refractive index layer, and refractive index of the sealing layer, and the results are shown in the table.

[Example 3]
Preparation of surface-treated zirconium oxide particle (3) powder for sealing In Example 1, a surface-treated zirconia fine particle (3) powder for sealing was prepared in the same manner except that the drying temperature was 80 ° C. in step (f). .
For the obtained surface-treated zirconia fine particles (3) for sealing, the average particle size (D _M2 ), average particle size (D _M1 ), and refractive index were measured, and the ²⁹ Si MAS NMR spectrum was measured. Are shown in Table 1.

Preparation of Sealing Fat Composition (3) A sealing fat composition (3) was prepared in the same manner as in Example 1 except that the surface-treated zirconia fine particles (3) for sealing were used.
Preparation of substrate with sealing layer (3) A substrate with sealing layer (3) was prepared in the same manner as in Example 1, except that the fat composition for sealing (3) was used. The thickness of the resin sealing layer at this time was 2 mm.
The obtained base material with sealing layer (3) was evaluated for total light transmittance, haze, adhesion to the high refractive index layer and refractive index of the sealing layer, and the results are shown in the table.

[Example 4]
Preparation of surface-treated zirconia fine particles (4) for sealing In Example 1, 9.0 g was added so that the organosilicon compound was 12.6 wt% as R ₁ —SiO _3/2 in step (e). A surface-treated zirconia fine particle (4) powder for sealing was prepared in the same manner except that.
For the obtained surface-treated zirconia fine particles (4) for sealing, the average particle diameter (D _M2 ), average particle diameter (D _M1 ), and refractive index were measured, and the ²⁹ Si MAS NMR spectrum was measured. Are shown in Table 1.

Preparation of sealing fat composition (4) A sealing fat composition (4) was prepared in the same manner as in Example 1 except that the surface-treated zirconia fine particles (4) for sealing were used.
Preparation of base material with sealing layer (4) In Example 1, a base material with sealing layer (4) was prepared in the same manner except that the sealing fat composition (4) was used. The thickness of the resin sealing layer at this time was 2 mm.
The obtained base material with sealing layer (4) was evaluated for total light transmittance, haze, adhesion to the high refractive index layer and refractive index of the sealing layer, and the results are shown in the table.

[Example 5]
Preparation of surface-treated zirconia fine particles (5) for sealing In Example 1, 22.4 g was added in step (e) so that the organosilicon compound was 26.5 wt% as R ₁ —SiO _3/2 A surface-treated zirconia fine particle (5) powder for sealing was prepared in the same manner except that.
About the obtained surface-treated zirconia fine particles (5) for sealing, the average particle diameter (D _M2 ), average particle diameter (D _M1 ), refractive index were measured, and ²⁹ Si MAS NMR spectrum was measured, and the result Are shown in Table 1.

Preparation of sealing fat composition (5) A sealing fat composition (5) was prepared in the same manner as in Example 1, except that the surface-treated zirconia fine particles (5) for sealing were used.
Preparation of base material with sealing layer (5) In Example 1, a base material with sealing layer (5) was prepared in the same manner except that the sealing fat composition (5) was used. The thickness of the resin sealing layer at this time was 2 mm.
The obtained base material with sealing layer (5) was evaluated for total light transmittance, haze, adhesion to the high refractive index layer and refractive index of the sealing layer, and the results are shown in the table.

[Example 6]
Preparation of surface-treated zirconia fine particles (6) for sealing In the step (b) of Example 1, hydrothermal treatment was performed at 180 ° C. for 3 hours, and thereafter the surface-treated zirconia fine particles for sealing (6 ) A powder was prepared.
For the obtained surface-treated zirconia fine particles (6) for sealing, the average particle diameter (D _M2 ), average particle diameter (D _M1 ), and refractive index were measured, and the ²⁹ Si MAS NMR spectrum was measured. Are shown in Table 1.

Preparation of Sealing Fat Composition (6) A sealing fat composition (6) was prepared in the same manner as in Example 1 except that the surface-treated zirconia fine particles (6) for sealing were used.
Preparation of substrate with sealing layer (6) A substrate with sealing layer (6) was prepared in the same manner as in Example 1 except that the fat composition for sealing (6) was used. The thickness of the resin sealing layer at this time was 2 mm.
The obtained base material with sealing layer (6) was evaluated for total light transmittance, haze, adhesion to the high refractive index layer, and refractive index of the sealing layer, and the results are shown in the table.

[Example 7]
Preparation of surface-treated zirconia fine particles (7) for sealing In step (b) of Example 1, tartaric acid added to the solution obtained by peptizing zirconia hydroxide gel was 531 kg, and in step (e) γ-methacrylo Example 1 except that γ-acrylooxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-5103) was used instead of oxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-503). In the same manner as above, surface-treated zirconia fine particles (6) for sealing were prepared.
About the obtained surface-treated zirconia fine particles (7) for sealing, the average particle diameter (D _M2 ), average particle diameter (D _M1 ), refractive index were measured, and ²⁹ Si MAS NMR spectrum was measured. Are shown in Table 1.

Preparation of sealing fat composition (7) A sealing fat composition (7) was prepared in the same manner as in Example 1 except that the surface-treated zirconia fine particles (7) for sealing were used.
Preparation of substrate with sealing layer (7) In Example 1, a substrate with sealing layer (7) was prepared in the same manner except that the sealing fat composition (7) was used. The thickness of the resin sealing layer at this time was 2 mm.
The obtained base material with a sealing layer (7) was evaluated for total light transmittance, haze, adhesion to the high refractive index layer and refractive index of the sealing layer, and the results are shown in the table.

[Example 8]
Preparation of surface-treated metal oxide fine particle (2) dispersion After obtaining a metal oxide fine particle (1) dispersion in the same manner as in Example 1, the solvent was replaced with methanol in an ultrafiltration membrane to obtain a solid content concentration of 9 7% by mass of metal oxide fine particle (2) dispersion was obtained.
Metal oxide fine particles (2) with a solid content concentration of 9.7% by mass (2) Dispersed in 13.9 g of a modified alcohol (Solmix AP-11 manufactured by Nippon Alcohol Sales Co., Ltd .: Ethanol 85.5 wt%, Isopropyl alcohol 9.8 wt% , Methanol (4.7%) 11.9 g was added and stirred. Further, tributoxy diluted with a denatured alcohol (manufactured by Nippon Alcohol Sales Co., Ltd .: Solmix AP-11: ethanol 85.5 wt%, isopropyl alcohol 9.8 wt%, methanol 4.7%) to a solid content concentration of 0.1 mass%. -13.5 g of monoacetonato zirconium (Nippon Soda Co., Ltd. ZR-181) was added and stirred to obtain a dispersion of surface-treated metal oxide fine particles (2) having a solid content concentration of 3.5%.
The average particle diameter and refractive index of the surface-treated metal oxide fine particles (2) were measured, and the results are shown in the table.

Preparation of binding material (2) Modified alcohol (Solmix AP-11 manufactured by Nippon Alcohol Sales Co., Ltd .: Ethanol 85.5 wt%, Isopropyl alcohol 9.8 wt%, Methanol 4.7%) 522 g with water 300 g and concentration 61 mass % Of nitric acid (4.9 g) was added and stirred, and then tetraethoxysilane (174 g) was added and stirred for 30 minutes. The binder (8) comprising a tetraethoxysilane hydrolyzate having a solid content concentration of 5.0% by mass. Got.

Preparation of surface-treated metal oxide fine particles (2) dispersion To 39.3 g of surface-treated metal oxide fine particles (2) dispersion, 12.0 g of PGME and 8.7 g of binder (2) were added to obtain a solid content concentration of 3. 0% by mass of a surface-treated metal oxide fine particle (2) dispersion was prepared.

Preparation of a substrate with a high refractive index layer (2) Surface-treated metal oxide fine particles (2) Dispersion was applied to a sapphire glass substrate (thickness: 0.43 mm, refractive index: 1.76, total light transmittance 82.0%). , Haze 0.0%) with a spin coater (500 rpm-120 seconds), heat treatment at 80 ° C. for 30 seconds, and heat treatment at 150 ° C. for 30 minutes to cure, with a high refractive index layer (2) A substrate was created. The thickness of the high refractive index layer (2) was 100 nm. The adhesion and surface roughness of the high refractive index layer (2) are shown in the table.

Preparation of sealing oil composition (8) In modified example 1, instead of 12.5 g of silicone resin (Ker-2500-A / KER-2500-B = 1/1 mixed solution manufactured by Shin-Etsu Chemical Co., Ltd.), modified silicone A sealing fat composition (8) was prepared in the same manner except that 12.5 g of a resin (SCR-1011-A / SCR-1011-B = 1/1 mixed solution manufactured by Shin-Etsu Chemical Co., Ltd.) was used.

Preparation of base material with sealing layer (8) In Example 1, the base with sealing layer was similarly used except that the sealing resin composition (8) was used instead of the sealing resin composition (1). Material (8) was created.
The obtained base material with sealing layer (8) was evaluated for total light transmittance, haze, adhesion to the high refractive index layer and refractive index of the sealing layer, and the results are shown in the table.

[Example 9]
Preparation of base material with sealing layer (9) The sealing fat composition (1) prepared in the same manner as in Example 1 was prepared using a sapphire glass substrate instead of the base material with high refractive index layer (1). Except for the above, it was cured in the same manner to prepare a substrate with a sealing layer (9). The thickness of the sealing layer at this time was 2 mm.
The obtained base material with a sealing layer (9) was evaluated for total light transmittance, haze, adhesion to the high refractive index layer and refractive index of the sealing layer, and the results are shown in the table.

[Comparative Example 1]
Preparation of surface-treated zirconia fine particles (R1) powder for sealing In Example 1, the same procedure was performed up to step (e), then the solvent was replaced with methanol in an ultrafiltration membrane, and then in a box dryer Then, it was dried at 60 ° C. for 24 hours to prepare a surface-treated zirconia fine particle (R1) powder for sealing.
For the obtained surface-treated zirconia fine particles (R1) for sealing, the average particle size (D _M2 ), average particle size (D _M1 ), and refractive index were measured, and the ²⁹ Si MAS NMR spectrum was measured. Are shown in Table 1.

Preparation of sealing fat composition (R1) A sealing fat composition (R1) was prepared in the same manner as in Example 1, except that the surface-treated zirconia fine particles (R1) for sealing were used.
Preparation of substrate with sealing layer (R1) A substrate with sealing layer (R1) was prepared in the same manner as in Example 1 except that the fat composition for sealing (R1) was used. The thickness of the resin sealing layer at this time was 2 mm.
The obtained base material with sealing layer (R1) was evaluated for total light transmittance, haze, adhesion to the high refractive index layer, and refractive index of the sealing layer, and the results are shown in the table.

[Comparative Example 2]
Preparation of surface-treated zirconia fine particles (R2) powder for sealing In Example 1, the same procedure was carried out until step (e), and then the solvent was replaced with methanol by an ultrafiltration membrane, and then by a box dryer. Then, it was dried at 40 ° C. for 72 hours to prepare a surface-treated zirconia fine particle (R2) powder for sealing.
For the obtained surface-treated zirconia fine particles (R2) for sealing, the average particle diameter (D _M2 ), average particle diameter (D _M1 ), refractive index were measured, and ²⁹ Si MAS NMR spectrum was measured. Are shown in Table 1.

Preparation of sealing fat composition (R2) A sealing fat composition (R2) was prepared in the same manner as in Example 1 except that the surface-treated zirconia fine particles (R2) for sealing were used.
Preparation of base material with sealing layer (R2) A base material with sealing layer (R2) was prepared in the same manner as in Example 1 except that the fat composition for sealing (R2) was used. The thickness of the resin sealing layer at this time was 2 mm.
The obtained base material with sealing layer (R2) was evaluated for total light transmittance, haze, adhesion to the high refractive index layer and refractive index of the sealing layer, and the results are shown in the table.

[Comparative Example 3]
Preparation of surface-treated zirconium oxide particles (R3) powder for sealing In Example 1, the same procedure was carried out until step (e), then the solvent was replaced with methanol in an ultrafiltration membrane, and then the box type dryer was used. Then, it was dried at 80 ° C. for 5 hours to prepare a surface-treated zirconium oxide particle (R3) powder for sealing.
For the obtained surface-treated zirconia fine particles (R3) for sealing, the average particle size (D _M2 ), average particle size (D _M1 ), and refractive index were measured, and ²⁹ Si MAS NMR spectrum was measured. Are shown in Table 1.

Preparation of sealing fat composition (R3) A sealing fat composition (R3) was prepared in the same manner as in Example 1 except that the surface-treated zirconia fine particles (R3) for sealing were used.
Preparation of substrate with sealing layer (R3) A substrate with sealing layer (R3) was prepared in the same manner as in Example 1 except that the fat composition for sealing (R3) was used. The thickness of the resin sealing layer at this time was 2 mm.
The obtained base material with sealing layer (R3) was evaluated for total light transmittance, haze, adhesion to the high refractive index layer, and refractive index of the sealing layer, and the results are shown in the table.

[Comparative Example 4]
Preparation of surface-treated zirconium oxide particles (R4) powder for sealing In the same manner as in Example 1, γ-methacrylooxypropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd.) as an organosilicon compound in zirconia fine particles (1) water / methanol dispersion. 11.2 g was added so that the organosilicon compound in the surface-treated zirconia fine particles obtained was 15.3% by weight as R ₁ —SiO _3/2 , and then stirred. While raising the temperature of the dispersion to 60 ° C., 1.6 g of aqueous ammonia having a concentration of 5% by weight was added for hydrolysis.

Next, the surface-treated zirconia fine particles (R4) for sealing were prepared by drying at 60 ° C. for 1.5 hours while gradually reducing the degree of pressure reduction to 50 hPa or less with a rotary evaporator.
About the obtained surface-treated zirconia fine particles (R4) for sealing, the average particle diameter (D _M2 ), average particle diameter (D _M1 ), refractive index were measured, and ²⁹ Si MAS NMR spectrum was measured, and the result Are shown in Table 1.

Preparation of sealing fat composition (R4) A sealing fat composition (R4) was prepared in the same manner as in Example 1 except that the surface-treated zirconia fine particles (R4) for sealing were used.
Preparation of substrate with sealing layer (R4) A substrate with sealing layer (R4) was prepared in the same manner as in Example 1 except that the fat composition for sealing (R4) was used. The thickness of the resin sealing layer at this time was 2 mm.
The obtained base material with sealing layer (R4) was evaluated for total light transmittance, haze, adhesion to the high refractive index layer and refractive index of the sealing layer, and the results are shown in the table.

[Comparative Example 5]
Preparation of base material with sealing layer (R5) The fat composition for sealing (R4) prepared in the same manner as in Comparative Example 4 was not a base material with a high refractive index layer (1) but a sapphire glass substrate. Except for the above, it was cured in the same manner to prepare a substrate with a sealing layer (R5). The thickness of the sealing layer at this time was 2 mm.
The obtained base material with sealing layer (R5) was evaluated for total light transmittance, haze, adhesion to the high refractive index layer, and refractive index of the sealing layer, and the results are shown in the table.

Claims (11)

In a light emitting diode comprising a die bond, a light emitting element, and a sealing layer,
The sealing layer is composed of organic resin and zirconia fine particles surface-treated with an organosilicon compound,
The surface-treated zirconia fine particles have an average secondary particle size (D _M2 ) in the range of 5 to 50 nm, an average primary particle size (D _M1 ) in the range of 5 to 50 nm, and the average secondary particle size (D _M2 ). A light-emitting diode characterized in that a ratio (D _M2 ) / (D _M1 ) of the average primary particle diameter (D _M1 ) is in the range of 1 to 10. The organosilicon compound is an organosilicon compound represented by the following formula (1), and the content of the organosilicon compound in the surface-treated zirconia fine particles is 1 to ₂ as R _n —SiO 2 _{(4-n) / 2} . 2. The light-emitting diode according to claim 1, wherein the light-emitting diode is in a range of 50 wt% and a half-width of a main peak of ²⁹ Si MAS NMR spectrum of the surface-treated zirconia fine particles is in a range of 3 to 15 ppm.
_{R n -SiX 4-n (1} )
(In the formula, R is an unsubstituted or substituted hydrocarbon group having 1 to 10 carbon atoms, and may be the same or different from each other. X: an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, Halogen, hydrogen, n: an integer of 1 to 3)   The high refractive index metal oxide fine particle layer having a refractive index in a range of 1.5 to 2.5 is provided between the light emitting element and the sealing layer. Light emitting diode.   4. The light emitting diode according to claim 3, wherein an average thickness of the high refractive index metal oxide fine particle layer is in a range of 20 to 300 nm.   The light emitting diode according to claim 3, wherein the high refractive index metal oxide fine particle layer has a surface roughness (Ra) in the range of 1 to 25 nm.   The light emitting diode according to claim 3, wherein the high refractive index metal oxide fine particles have an average particle diameter in the range of 3 to 50 nm.   4. The light emitting diode according to claim 3, wherein the high refractive index metal oxide fine particle layer further contains a binder together with the high refractive index metal oxide fine particles.   The light emitting diode according to claim 7, wherein the binder is a hydrolyzed polycondensate of a hydrolyzable metal compound.   The light emitting diode according to claim 7, wherein the content of the binder is in the range of 5 to 40 wt% as a solid content in the high refractive index metal oxide fine particle layer.   The light emitting diode according to claim 1, wherein a refractive index of the sealing layer is lower than a refractive index of the high refractive index metal oxide fine particle layer.   The light emitting diode according to claim 1, wherein the organic resin is an epoxy resin or a silicone resin.

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