JP2014078691A - Wavelength conversion component for semiconductor light-emitting device and semiconductor light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wavelength conversion component for a semiconductor light-emitting device whose characteristic does not easily vary within a manufacturing lot or between manufacturing lots.SOLUTION: Provided is a wavelength conversion component for a semiconductor light-emitting device, the wavelength conversion component comprising a polymer composition formed by dispersing a phosphor and two or more kinds of optical diffusion materials differing in refractive index from each other into a polymer binder. When one of the optical diffusion materials having higher refractive index than the other is assumed to be a high-refractive-index optical diffusion material and one of the optical diffusion materials having lower refractive index than the other is assumed to be a low-refractive-index optical diffusion material, then the refractive index of the polymer binder at room temperature is lower than the refractive index of the high-refractive-index optical diffusion material and higher than the refractive index of the low-refractive-index optical diffusion material.

Description

  The present invention relates to a wavelength conversion component for a semiconductor light emitting device and a semiconductor light emitting device.

  A semiconductor light emitting device configured to generate white light by combining a light emitting diode (LED) and a phosphor that converts a part of light (primary light) emitted from the LED into light of different wavelength (secondary light). The device is known. In such semiconductor light emitting devices, attempts have been made to make components responsible for the wavelength conversion function into components. As an example, there is known a wavelength conversion component formed of a composition in which a phosphor is dispersed in an optically transparent polymer binder (Patent Document 1; using a wavelength conversion component called “Fluorescent plate”. LED package "is disclosed).

  Recently, an LED device for illumination called a remote phosphor type LED device in which a large wavelength conversion component is combined with a high output LED has been developed (Patent Document 2). In the remote phosphor type LED device, in order to reduce the cost, it is required to reduce the amount of phosphor used in the wavelength conversion component as much as possible. Therefore, in order to efficiently use a small amount of phosphor for wavelength conversion, a light diffusing agent is added to the resin composition, which is a material, in addition to the phosphor, and the primary light is converted into phosphor particles inside the wavelength conversion component. A method for increasing the chance of interaction has been proposed (FIG. 12 of Patent Document 2).

JP 2001-111171 A US Patent Application Publication US2012 / 0087105

  In the case of a wavelength conversion component formed of a composition in which a phosphor is dispersed in an optically transparent binder containing a polymer, the phosphor is efficiently dispersed by dispersing the light diffusing material in the binder together with the phosphor. It can be considered that it can be used for wavelength conversion. However, even in such a case, there is a concern that the characteristics of the wavelength conversion component may greatly fluctuate due to the dispersion state of the light diffusing material.

  Therefore, a main object of the present invention is to provide a wavelength conversion component for a semiconductor light-emitting device that is less likely to cause a characteristic variation within a production lot or between production lots, and to provide a preferred method for producing such a wavelength conversion component. There is. And it is providing the wavelength conversion component which expresses the stable light-diffusion property at the time of LED use especially suitable for a remote phosphor type | mold LED device.

Embodiments of the present invention include the wavelength conversion component described in the following (a1) to (a7) and the semiconductor light emitting device described in the following (a8).
(A1) A wavelength conversion component comprising a polymer composition in which a phosphor and two or more kinds of light diffusing materials having different refractive indexes are dispersed in a polymer binder, wherein the light diffusing material has a higher refractive index. When a light diffusing material is a light diffusing material having a high refractive index and a light diffusing material having a lower refractive index is a light diffusing material having a low refractive index, the refractive index of the polymer binder at room temperature. A wavelength conversion component for a semiconductor light emitting device, which is lower than the refractive index of the light diffusing material having a high refractive index and higher than the refractive index of the light diffusing material having a low refractive index.
(A2) The wavelength conversion component according to (a1), wherein a thermal expansion coefficient of the polymer binder is higher than a thermal expansion coefficient of the high refractive index light diffusing material and a low refractive index light diffusion material.
(A3) The polymer binder contains a silicone polymer, (a1) or (a
The wavelength conversion component according to 2).
(A4) The wavelength conversion component according to any one of (a1) to (a3), wherein the polymer composition contains at least one selected from spherical silica or silicone particles as the light diffusing material.
(A5) The wavelength conversion component according to (a4), wherein the polymer composition contains spherical silica as the high-refractive index light diffusing material and silicone particles as the low-refractive index light diffusing material.
(A6) The wavelength conversion component according to (a4) or (a5), wherein the polymer composition contains at least one of silicone particles and spherical silica that do not act as a light diffusing material.
(A7) At room temperature, at least one of a refractive index difference between the binder and the high refractive index light diffusing material and a refractive index difference between the binder and the low refractive index light diffusing material is 0.1 or less. The wavelength conversion component according to any one of (a1) to (a6).
(A8) At room temperature, the refractive index difference between the binder and the high refractive index light diffusing material and the refractive index difference between the binder and the low refractive index light diffusing material are both 0.1 or less. The wavelength conversion component as described in a7).
(A9) A wavelength conversion component according to any one of (a1) to (a8) and a semiconductor light emitting element, wherein at least a part of light emitted by the semiconductor light emitting element varies depending on the wavelength conversion component Semiconductor light-emitting device that is converted into light.

In addition, the embodiment of the present invention includes the wavelength conversion component described in the following (b1) to (b8) and the semiconductor light emitting device described in the following (b9).
(B1) A polymer composition containing a binder containing a polymer, a phosphor and a light diffusing material dispersed in the binder, and the refractive index difference between the binder and the light diffusing material at room temperature is 0. A wavelength conversion component for a semiconductor light emitting device, which is 1 or less.
(B2) The wavelength conversion component according to (b1), wherein the binder contains a silicone polymer.
(B3) The wavelength conversion component according to (b2), wherein the polymer composition contains at least one selected from spherical silica or silicone particles as the light diffusing material.
(B4) The wavelength conversion component according to (b3), wherein the polymer composition contains both spherical silica and silicone particles as the light diffusing material.
(B5) The wavelength conversion component according to (b3), wherein the polymer composition contains spherical silica as the light diffusing material and contains silicone particles that do not act as a light diffusing material as a filler.
(B6) The wavelength conversion component according to (b3), wherein the polymer composition contains silicone particles as the light diffusing material and spherical silica that does not act as a light diffusing material as a filler.
(B7) The polymer composition contains a first light diffusing material and a second light diffusing material having different refractive indexes as the light diffusing material, and the refractive index of the binder is n _B at room temperature. wherein the refractive index of the diffusing material _{n 1,} and the refractive index of the second light diffusing material was changed to _{n 2,} the _{n 1 <n} B _{<n 2} or _n 2 _<n B <the a _{n 1} (b1) Wavelength conversion component.
(B8) The binder according to (b7), wherein the binder contains a silicone polymer, and the polymer composition contains spherical silica as the first light diffusing material and silicone particles as the second light diffusing material. Wavelength conversion component.
(B9) The wavelength conversion component according to any one of (b1) to (b8) and a semiconductor light emitting element, wherein at least part of the light emitted by the semiconductor light emitting element has a wavelength different depending on the wavelength conversion component. A semiconductor light-emitting device that is converted to light.

In addition, the embodiments of the present invention include the wavelength conversion component described in (c1) to (c10) below and the semiconductor light emitting device described in (c11) below.
(C1) a silicone composition containing a binder containing a silicone polymer, a phosphor and a light diffusing material dispersed in the binder, and the silicone composition is made of spherical silica or silicone particles as the light diffusing material. A wavelength conversion component for a semiconductor light-emitting device, containing at least one selected.
(C2) The wavelength conversion component according to (c1), wherein the silicone composition contains both spherical silica and silicone particles as the light diffusing material.
(C3) The wavelength conversion component according to (c1), wherein the silicone composition contains spherical silica as the light diffusing material and silicone particles that do not act as a light diffusing material as a filler.
(C4) The wavelength conversion component according to (c1), wherein the silicone composition contains silicone particles as the light diffusing material and spherical silica that does not act as a light diffusing material as a filler.
(C5) At room temperature, when the refractive index of the binder is n _B , the refractive index of the spherical silica is n ₁ , and the refractive index of the silicone particles is n ₂ , n ₁ <n _B <n ₂ or n ₂ < The wavelength conversion component according to (c2), wherein n _B <n ₁ is satisfied.
(C6) The wavelength conversion component according to any one of (c1) to (c5), wherein the silicone composition contains fumed silica.
(C7) The wavelength conversion component according to any one of (c1) to (c4), wherein the silicone composition contains spherical silica, and the specific surface area of the spherical silica is 1 to 10 m ² / g.
(C8) The wavelength conversion component according to (c7), wherein the spherical silica has a median diameter in the range of 1 to 20 μm.
(C9) The wavelength conversion component according to (c1) to (c4), (c7), or (c8), wherein the silicone composition contains a spherical silicone resin as the silicone particles.
(C10) The wavelength conversion component according to (c9), wherein the spherical silicone resin has a median diameter in the range of 1 to 20 μm.
(C11) The wavelength conversion component according to any one of (c7) to (c10), including a molded product formed of the silicone composition.
(C12) The wavelength conversion component according to any one of (c1) to (c11) and a semiconductor light emitting element, wherein at least part of the light emitted by the semiconductor light emitting element has a wavelength different depending on the wavelength conversion component A semiconductor light-emitting device that is converted to light.

Moreover, the embodiment of the present invention includes a method for manufacturing a wavelength conversion component described in the following (d1) to (d10).
(D1) a first silicone composition containing a binder containing a silicone polymer, and a phosphor and a light diffusing material dispersed in the binder, wherein the silicone composition is spherical silica or spherical as the light diffusing material. A method for producing a wavelength conversion component for a semiconductor light-emitting device containing at least one selected from silicone resins, comprising: preparing a thermosetting silicone composition that becomes the first silicone composition by curing; The manufacturing method of the wavelength conversion component which has a process and the 2nd process of forming a molding from this thermosetting silicone composition.
(D2) The production method according to (d1), wherein a difference in refractive index between the binder and the light diffusing material at room temperature is 0.1 or less.
(D3) The production method according to (d1) or (d2), wherein the first silicone composition contains both spherical silica and a spherical silicone resin as the light diffusing material.
(D4) The manufacturing method according to (d1) or (d2), wherein the first silicone composition contains spherical silica as the light diffusing material and a spherical silicone resin that does not act as a light diffusing material as a filler. .
(D5) The manufacturing method according to (d1) or (d2), wherein the first silicone composition contains a spherical silicone resin as the light diffusing material, and contains spherical silica that does not act as a light diffusing material as a filler. .
(D6) at room temperature, the refractive index _{n B} of the binder, _{n 1} the refractive index of the spherical silica, and the refractive index of the spherical silicone resin was _{n 2,} an _{n 2 <n B <n 1} , The manufacturing method as described in said (d3).
(D7) The production method according to any one of (d1) to (d6), wherein the first silicone composition contains fumed silica.
(D8) The production method according to any one of (d1) to (d5), wherein the silicone composition contains spherical silica, and the specific surface area of the spherical silica is 1 to 10 m ² / g.
(D9) The production method according to (d8), wherein the spherical silica has a median diameter in the range of 1 to 20 μm.
(D10) The production method according to (d1) to (d5), (d8), or (d9), wherein the silicone composition contains a spherical silicone resin.
(D11) The production method according to (d10), wherein the spherical silicone resin has a median diameter in the range of 1 to 20 μm.

Moreover, the thermosetting silicone composition as described in the following (e1)-(e10) is contained in embodiment of this invention.
(E1) A thermosetting silicone composition that can be used for the production of the following first wavelength conversion component and becomes the following first silicone composition by curing:
The first wavelength converting component includes a first silicone composition containing a binder containing a silicone polymer, a phosphor and a light diffusing material dispersed in the binder, and the first silicone composition is the light diffusing material. It is a wavelength conversion component for semiconductor light-emitting devices containing at least one selected from spherical silica or silicone particles as a material.
(E2) The thermosetting silicone composition according to (e1), wherein a difference in refractive index between the binder and the light diffusing material at room temperature is 0.1 or less.
(E3) The thermosetting silicone composition according to (e1) or (e2), wherein the first silicone composition contains both spherical silica and silicone particles as the light diffusing material.
(E4) The thermosetting property according to (e1) or (e2), wherein the first silicone composition contains spherical silica as the light diffusing material and contains silicone particles that do not act as a light diffusing material as a filler. Silicone composition.
(E5) The thermosetting property according to (e1) or (e2), wherein the first silicone composition contains silicone particles as the light diffusing material and spherical silica that does not act as a light diffusing material as a filler. Silicone composition.
(E6) At room temperature, when the refractive index of the binder is n _B , the refractive index of the spherical silica is n ₁ , and the refractive index of the silicone particles is n ₂ , n ₁ <n _B <n ₂ or n ₂ < The thermosetting silicone composition according to (e3), wherein n _B <n ₁ is satisfied.
(E7) The thermosetting silicone composition according to any one of (e1) to (e6), wherein the first silicone composition contains fumed silica.
(E8) The thermosetting silicone according to any one of (e1) to (e5), wherein the first silicone composition contains spherical silica, and the specific surface area of the spherical silica is 1 to 10 m ² / g. Composition.
(E9) The thermosetting silicone composition according to (e8), wherein the spherical silica has a median diameter in the range of 1 to 20 μm.
(E10) The thermosetting silicone composition according to (e1) to (e5), (e8), or (e9), wherein the first silicone composition contains a spherical silicone resin as the silicone particles.
(E11) The thermosetting silicone composition according to (e10), wherein the spherical silicone resin has a median diameter in the range of 1 to 20 μm.

The wavelength conversion components (a1) and (b1) have a small difference in refractive index between the binder and the light diffusing material, so even if the dispersion state of the light diffusing material varies within the production lot or between production lots, The resulting characteristic variation is relatively small.
In the wavelength conversion component (c1) above, a silicone polymer is selected as the binder polymer, and spherical silica or silicone particles having a small refractive index difference from the silicone polymer are selected as the light diffusing material. Even if the dispersion state of the light diffusing material varies between the production lots, the characteristic variation caused by the variation is relatively small.

It is a graph which shows the relationship between the "whiteness index" in a silicone composition, and the volume ratio of spherical silica (volume ratio of the spherical silica which occupies for a micron size filler (spherical silica and spherical silicone resin)). It is a graph which shows the relationship between the "whiteness index" in a silicone composition, and the volume ratio of spherical silica (volume ratio of the spherical silica which occupies for a micron size filler (spherical silica and spherical silicone resin)).

  Hereinafter, the present invention will be described with reference to embodiments. However, the present invention is not limited to the embodiments described explicitly or implicitly in the present specification, and various modifications can be made without departing from the spirit of the present invention.

[Embodiment 1]
The wavelength conversion component according to Embodiment 1 is formed of a silicone composition containing a binder (A) containing a polymer, a phosphor (B) and spherical silica (C) dispersed therein, and the spherical silica. Is a wavelength conversion component that acts as a light diffusing material. The silicone composition may contain various components (D) other than (A), (B), and (C) as necessary. The polymer contained in the binder (A) is preferably a silicone polymer. Hereinafter, in the present embodiment, the case where the binder (A) contains a silicone polymer will be described as a representative example.

  In order for the spherical silica (C) to act as a light diffusing material, a difference in refractive index needs to exist between the binder (A) and the spherical silica (C). In the case of fused silica which is a preferred example of spherical silica (C) (spherical silica produced by a method in which pulverized raw meteorite is melted in a high-temperature flame and spheroidized by surface tension), a semiconductor used in a semiconductor light emitting device Since the refractive index in the light emission wavelength range (near ultraviolet to blue wavelength range) of the light emitting element is usually 1.46 to 1.47, the silicone polymer used as the binder is used as the refractive index in order to cause fused silica to act as a light diffusing material. Is preferably 1.40 to 1.45 or 1.48 to 1.55.

It should be noted that when the semiconductor light emitting device is driven, the wavelength conversion component is heated by the irradiation of light emitted from the semiconductor light emitting element, and the binder is thermally expanded. In selecting a silicone polymer to be used as a binder, a reduction in refractive index due to this thermal expansion should be taken into consideration.
When ultrafine particles with a primary particle size of several tens of nanometers such as fumed silica are dispersed in the binder, the refractive index of the binder is the average of the refractive index of the silicone polymer and the refractive index of the ultrafine particles. It is also necessary to pay attention to the actual value (value determined by each refractive index and volume ratio).

The wavelength conversion component according to Embodiment 1 may include a molded product formed of the silicone composition, or the silicone composition may be applied to the surface of a transparent or reflective substrate. It may be included in the form of an attached coating. In the former case, the shape of the molded product is not limited, and may be any shape including those disclosed in Patent Document 1 and Patent Document 2 (planar plate, planar disk, non-planar disk, dome, etc.). obtain.
Preferred examples of the molding method include an injection molding method such as a liquid injection molding method and a transfer molding method.
Hereinafter, each component which the silicone composition which concerns on this Embodiment 1 can contain is demonstrated.

<Binder (A)>
As the binder polymer, a silicone polymer is usually used. The silicone polymer is also called an organopolysiloxane, and has a siloxane bond in the main chain, and therefore has extremely good heat resistance and light resistance. The heat resistance and light resistance of the silicone polymer tend to increase as the proportion of methyl groups in the total hydrocarbon groups bonded to silicon atoms increases.

  The refractive index of the silicone polymer is usually about 1.42 when polydimethylsiloxane is used as a basic skeleton. By substituting the hydrogen atom of the methyl group contained in this silicone polymer with a fluorine atom, the refractive index is further lowered. Conversely, when the methyl group contained in the silicone polymer is replaced with an aryl group such as a phenyl group, the refractive index is increased. Various curable silicones having a refractive index of the cured product (= silicone polymer) in the range of 1.40 to 1.55 are commercially available.

The curable silicone is classified into an addition curing type, a condensation curing type, an ultraviolet curing type, a peroxide crosslinking type, and the like depending on the curing mechanism. Any type of curable silicone can be used, but preferred are the addition cure type and the condensation cure type.
In particular, when the wavelength conversion component is manufactured by a molding method, it is preferable to select an addition-curable type curable silicone that is cured by a hydrosilylation reaction. This is because no by-product is generated at the time of curing, so that the pressure in the mold does not become abnormally high, and sink marks and bubbles are hardly generated in the molded product.

A type of curable silicone that cures by a hydrosilylation reaction usually contains an organopolysiloxane having a hydrosilyl group (first component), an organopolysiloxane having an alkenyl group (second component), and a curing catalyst.
As the first component, those having two or more hydrosilyl groups in the molecule are preferably used. For example, polydiorganosiloxane having hydrosilyl groups at both ends, polymethylhydrosiloxane having both ends blocked with trimethylsilyl groups, methylhydrosiloxane-dimethylsiloxane copolymer, and the like.

As the second component, those having at least two vinyl groups bonded to silicon atoms in one molecule are preferably used.
In addition, an organopolysiloxane having both the first component and the second component, that is, an organopolysiloxane having both a hydrosilyl group and an alkenyl group in one molecule may be used.

  The curing catalyst is a catalyst for promoting the addition reaction between the hydrosilyl group in the first component and the alkenyl group in the second component. Examples thereof include platinum black, second platinum chloride, chloroplatinic acid, chloride. Examples thereof include a reaction product of platinum acid and a monohydric alcohol, a complex of chloroplatinic acid and olefins, a platinum catalyst such as platinum bisacetoacetate, a platinum group metal catalyst such as a palladium catalyst and a rhodium catalyst.

<Phosphor (B)>
As a fluorescent substance, the inorganic fluorescent substance currently used for general white LED can be used without a restriction | limiting.
A wavelength conversion component for a white light emitting device using a near ultraviolet LED or a violet LED as a light source usually contains a blue phosphor, a green phosphor, and a red phosphor. In addition to the green phosphor or instead of the green phosphor, a yellow phosphor can be used. The color temperature of the output light can be adjusted by changing the ratio of the content of each phosphor.

A wavelength conversion component for a white light emitting device using a blue LED as a light source usually contains a yellow phosphor. In order to generate white light having a low color temperature such as a bulb color or warm white, a red phosphor may be used in combination. The combined use of the red phosphor also helps to improve the color rendering properties of the light emitting device. In order to obtain better color rendering properties, a green phosphor can be used in addition to the red phosphor.
Preferred examples of the blue phosphor include (Ca, Sr, Ba) MgAl ₁₀ O ₁₇ : Eu, (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ (Cl, F) ₂ : Eu, and the like.

Preferred examples of the green phosphor include Y ₃ (Al, Ga) ₅ O ₁₂ : Ce, (Sr, Ba) ₂ SiO ₄ : Eu, β-type sialon: Eu, Sr ₃ Si ₁₃ Al ₃ O ₂ N ₂₁ : Eu Sr ₅ Al ₅ Si ₂₁ O ₂ N ₃₅ : Eu.
Preferable examples of the yellow phosphor include Y ₃ Al ₅ O ₁₂ : Ce, (Y, Gd) ₃ Al ₅ O ₁₂ : Ce, (Sr, Ca, Ba, Mg) ₂ SiO ₄ : Eu and the like.

Preferred examples of the red phosphor include (Ca, Sr, Ba) ₂ Si ₅ (N, O) ₈ : Eu, (Ca, S
r, Ba) AlSi (N, O) ₃ : Eu, (La, Y) ₂ O ₂ S: Eu, SrAlSi ₄ N ₇
: Eu, K ₂ SiF ₆ : Mn, etc.
The total amount of the phosphor contained in the silicone composition is preferably 40% by weight or less, more preferably 30% by weight or less. In the case of a wavelength conversion component for a white light emitting device having a color temperature of about 4000 K using a blue LED, the present inventors reduced the usage amount of the phosphor to 3.5 weight of the silicone composition without reducing the light emission efficiency. It is confirmed that it can be reduced to as much as%.

<Spherical silica (C)>
Spherical silica is true spherical silica particles used as a filler for epoxy resin used for semiconductor encapsulation. Spherical silica produced by various production methods is commercially available and can be used as appropriate.
As described above, in the case of fused silica, the refractive index in the near ultraviolet to blue wavelength region is usually 1.46 to 1.47, but the refractive index of spherical silica having a larger specific surface area is lower than this. This is because silica having a large specific surface area has a porous structure.

The amount of spherical silica dispersed in the silicone composition is adjusted so that the desired light diffusibility is obtained.
The specific surface area of the spherical silica is preferably 1 to 10 m ² / g, more preferably 1 to 5 m ² / g. By using spherical silica having such a specific surface area, fluidity suitable for molding such as an injection mold and a transfer mold can be imparted to the silicone composition before curing. A suitable example of the spherical silica having such a specific surface area is fused silica. On the other hand, when a large amount of spherical silica having a specific surface area exceeding 50 m ² / g is added to the silicone composition before curing, the viscosity becomes too high and molding may be difficult.

  The particle diameter of the spherical silica in the silicone composition can be, for example, 0.3 to 50 μm. In order to give fluidity suitable for molding such as injection mold and transfer mold to the silicone composition before curing, the particle diameter is preferably 1 μm or more, and on the other hand, it is preferably 30 μm or less. , 20 μm or less is particularly preferable. As the spherical silica, particle groups having different particle diameters can be used. In this case, it is preferable that the median diameter of the particle group is within the above preferable range. Further, the presence of particles having a particle diameter of less than 1 μm or more than 20 μm is not unacceptable, but the number of such particles is preferably less than 50%, more preferably less than 25%.

  In order to provide the silicone composition before curing with fluidity suitable for molding, the content of the spherical silica having the preferable specific surface area and particle size is preferably 30 to 90% by volume, particularly 45 to 90% by volume. preferable. However, if the refractive index difference between the spherical silica and the binder is large, the light diffusibility may become too strong when the addition amount of the spherical silica is within this range. In that case, a part of the spherical silica is replaced with a spherical silicone resin described later (however, the refractive index difference from the binder is smaller than that of the spherical silica), and the total content of the spherical silica and the spherical silicone resin is changed to that of the silicone composition. It may be 30 to 90% by volume, particularly 45 to 90% by volume.

<Other components (D)>
Silicone particles can be added to the silicone composition.
Silicone particles include rubber particles, resin particles, and composite particles (the surface of rubber particles coated with resin). Commercially available products include KMP series, KSP series and X-52 series from Shin-Etsu Chemical Co., Ltd., silicone rubber powder from Toray Dow Corning Co., Ltd., Momentive Performance Materials Japan (same) Tospearl (registered trademark) and the like can be mentioned.

<Particle size of each material>
The particle diameter of each material contained in the silicone composition according to the present invention can be confirmed by microscopic observation. Moreover, when using particle groups with different particle diameters, it is preferable that the median diameter of the particle groups is within the range of preferable particle diameters of the respective materials. When using a commercially available material, a material having an appropriate particle size may be selected with reference to the particle size described in a catalog or the like.

Silicone particles that can be preferably added for the purpose of imparting fluidity suitable for molding to the silicone composition before curing are spherical silicone resins.
Spherical silicone resin is a spherical three-dimensional crosslinked silicone particle having a polyalkylsilsesquioxane structure, and commercially available silicone resin powder (KMP-590, 701 702 / X-52-854 / X52-1621), Tospearl (registered trademark) of Momentive Performance Materials Japan (same), and the like.

The particle diameter of the spherical silicone resin in the silicone composition can be, for example, 0.5 to 50 μm. In order to provide the silicone composition before curing with fluidity suitable for molding such as injection mold and transfer mold, the shape of the spherical silicone resin is preferably close to a true sphere, and the particle diameter is 1 μm or more. Is preferred,
On the other hand, it is preferably 30 μm or less, and more preferably 20 μm or less. As the spherical silicone resin, particles having different particle diameters can be used. In this case, it is preferable that the median diameter of the particle group is within the above preferable range. Further, the presence of particles having a particle diameter of less than 1 μm or more than 20 μm is not unacceptable, but the number of such particles is preferably less than 50%, more preferably less than 25%.

A spherical silicone resin having a refractive index close to that of the binder (including the case where it is the same) may be added to the silicone composition for the purpose of increasing the hardness of the silicone composition without significantly changing the light diffusibility. it can.
In one example, the silicone particles are made of a resin or rubber having a high degree of cross-linking and have a smaller thermal expansion coefficient than that of the binder. At room temperature, the refractive index n _B of the binder is the refractive index n _{1 of} spherical silica. Diffusion of the silicone composition as the temperature rises by selecting the material so that it is in the middle of the refractive index n ₂ of the silicone particles (n ₁ <n _B <n ₂ or n ₂ <n _B <n ₁ ) Sex change can be suppressed.

For example, in the case of n ₂ <n _B <n ₁ , when the binder thermally expands due to temperature rise and the refractive index decreases, the difference in refractive index between the binder and spherical silica increases, but the binder and silicone particles On the contrary, the refractive index difference of becomes smaller. Therefore, the increase in light diffusivity due to the difference in refractive index between the binder and spherical silica is offset by the decrease in light diffusivity due to the difference in refractive index between the binder and the silicone particles.

Fumed silica can be added to the silicone composition for the purpose of imparting thixotropy or adjusting fluidity. Fumed silica is an ultrafine particle having a large specific surface area of 50 m ² / g or more. Examples of commercially available fumed silica include Aerosil (registered trademark) of Nippon Aerosil Co., Ltd., WACKER HDK of Asahi Kasei Wacker Silicone Co., Ltd. ( Registered trademark).

By imparting thixotropy to the silicone composition before curing, it is possible to prevent the phosphor from precipitating in the binder during storage or molding and uneven distribution thereof.
Preparation of the fluidity of the silicone composition before curing is particularly important when the silicone composition is molded by a transfer molding method or an injection molding method.

[Embodiment 2]
In Embodiment 2, silicone particles are used for the light diffusing material instead of the spherical silica in Embodiment 1 described above. That is, the wavelength conversion component according to Embodiment 2 is formed of a composition containing a binder containing a polymer, a phosphor and silicone particles dispersed therein, and a wavelength at which the spherical silicone acts as a light diffusing material. It is a conversion component.

[Embodiment 3]
The wavelength conversion component according to Embodiment 3 includes a polymer composition containing a polymer-containing binder (A), a phosphor (B) dispersed therein, and two or more types of light diffusing materials having different refractive indexes. And a wavelength conversion component formed of an object. The composition may contain various components other than (A), (B) and two or more kinds of light diffusing materials having different refractive indexes as necessary.

In the wavelength conversion component according to the third embodiment, the light diffusing material having a higher refractive index among the light diffusing materials is the light diffusing material having the higher refractive index, and the light diffusing material having the lower refractive index among the light diffusing materials. Is a light diffusing material having a low refractive index, the refractive index of the polymer binder is lower than the refractive index of the light diffusing material having a high refractive index and higher than the refractive index of the light diffusing material having a low refractive index at room temperature. It has become. Here, the thermal expansion coefficient of the polymer binder is preferably higher than the thermal expansion coefficient of the light diffusing material having a high refractive index and the thermal expansion coefficient of the light diffusing material having a low refractive index.

More specifically, for example, it contains a silicone polymer as a polymer binder, and as a light diffusing material having a low refractive index, contains silicone particles having a smaller thermal expansion coefficient than a binder formed of a resin or rubber having a high degree of crosslinking. In addition to containing spherical silica as a high-refractive index light diffusing material, at room temperature, the material is made such that the refractive index n _B of the binder is intermediate between the refractive index n _{1 of} spherical silica and the refractive index n ₂ of silicone particles. By selecting, the change of the light diffusibility of the polymer composition accompanying a temperature rise can be suppressed.

For example, in the case of n ₂ <n _B <n ₁ , when the binder thermally expands due to temperature rise and the refractive index decreases, the difference in refractive index between the binder and spherical silica increases, but the binder and silicone particles On the contrary, the refractive index difference between and becomes smaller. Therefore, the increase in light diffusivity due to the difference in refractive index between the binder and spherical silica is offset by the decrease in light diffusivity due to the difference in refractive index between the binder and the silicone particles.

As the polymer binder according to Embodiment 3, various known LED sealing resins can be used. Specific examples include a silicone resin, an acrylic resin, an epoxy resin, a urethane resin, and a transparent resin selected from these modified resins.
Moreover, as a light-diffusion material which concerns on Embodiment 3, well-known various fillers for LED sealing can be used. Specific examples include silica, silicone resin, aluminum nitride, boron nitride, titania, alumina, magnesium oxide, magnesium hydroxide, zirconia and the like.

  A wavelength conversion component that exhibits stable light diffusibility can be obtained by selecting a combination of materials having a refractive index and / or a thermal expansion coefficient satisfying the above relationship from among these various materials. In the case of selecting the silicone polymer, specifically, the refractive index of the silicone polymer is usually about 1.41 for polydimethylsiloxane as a basic skeleton, but the methyl group contained in the silicone polymer has a refractive index of about 1.41. By substituting a hydrogen atom for a fluorine atom, the refractive index is lowered. When a methyl group contained in the silicone polymer is replaced with an aryl group such as a phenyl group, the refractive index is increased. Therefore, a material satisfying the above relationship may be selected from commercially available various curable silicones, or a silicone polymer satisfying the above relationship may be synthesized and used.

  In the polymer composition according to Embodiment 3, when the total amount of the binder (A) containing the polymer, the phosphor (B) dispersed in the binder and the light diffusing material is 100% by weight, the binder containing the polymer The content of (A) is usually 20% by weight or more, preferably 25% by weight or more, and on the other hand, it is usually 60% by weight or less, preferably 40% by weight or less. The content of the phosphor (B) dispersed in the binder is usually 3% by weight or more, preferably 5% by weight or more, and on the other hand, usually 40% by weight or less, preferably 30%. % By weight or less. The remainder is the total content of the light diffusing material. In the polymer composition according to Embodiment 3, when the total amount of the binder (A) containing the polymer, the phosphor (B) dispersed in the binder and the light diffusing material is 100% by volume, two or more types The total content of the light diffusing materials having different refractive indexes is usually 30% by volume or more, preferably 45% by volume or more, and on the other hand, usually 90% by volume or less.

[Molding method]
A compression mold, a transfer mold, or an injection mold can be suitably used for manufacturing the wavelength conversion component according to Embodiments 1 and 2 and other embodiments. Among them, injection molds, especially liquid injection molds (LIM), are less likely to generate burrs, so secondary processing (deburring) is unnecessary, automation is easy, and molding cycles can be shortened easily. Compared with the transfer mold, the LIM has a higher degree of freedom in designing the shape of the molded product, and the molding machine and the mold are less expensive.

  The cylinder set temperature in the injection mold is usually 100 ° C. or lower, preferably 80 ° C. or lower, more preferably 60 ° C. or lower. The mold temperature is usually 80 ° C. or higher, preferably 100 ° C. or higher, more preferably 120 ° C. or higher. On the other hand, it is usually 300 ° C. or lower, preferably 250 ° C. or lower, more preferably 200 ° C. or lower. The injection time is usually 1 second or less for short cases and several seconds for long cases. The molding time is usually 3 seconds or more, preferably 5 seconds or more, more preferably 10 seconds or more, and on the other hand, it is usually 600 seconds or less, preferably 200 seconds or less, more preferably 60 seconds or less.

  In a liquid injection mold (LIM), a low temperature raw material resin is fed into a high temperature mold. Since the inside of the flow path is also heated, the viscosity of the raw material resin increases as it approaches the mold due to a partial thermosetting reaction. When the resin viscosity when reaching the mold is low, the resin leaks out from the gap between the molds and becomes burrs. Therefore, in order to prevent the occurrence of burrs, it is important to control the viscosity of the resin and increase the mold accuracy (narrow the gap). The gap of the mold is usually required to be 10 μm or less, preferably 5 μm or less, more preferably 3 μm or less.

  On the other hand, when the viscosity increase of the raw material resin is too fast, unfilling of the mold occurs. In order to suppress the occurrence of burrs and prevent unfilling of the mold, the degree of cure of the resin rises in a S-curve with time on the graph with the horizontal axis representing time and the vertical axis representing the degree of cure. Ideally. The curing rate of the resin can be controlled by material design (selection of catalyst type, catalyst amount, use of curing rate control agent, degree of crosslinking of the resin, etc.) and molding conditions (mold temperature, filling rate, injection pressure, etc.). The time from the injection of the resin into the mold to the end of curing is usually 60 seconds or less, preferably 30 seconds or less, more preferably 10 seconds or less.

Making the inside of the mold a vacuum at the time of molding is an effective means for promoting the inflow of the resin into the narrow cavity and preventing the generation of air voids in the molded product.
In the case of a compression mold, the molding temperature is usually 80 ° C. or higher, preferably 100 ° C. or higher, more preferably 120 ° C. or higher, and usually 300 ° C. or lower, preferably 250 ° C. or lower, more preferably 200 ° C. It is as follows. The molding time is usually 3 seconds or more, preferably 5 seconds or more, more preferably 10 seconds or more, and on the other hand, it is usually 1200 seconds or less, preferably 900 seconds or less, more preferably 600 seconds or less.

  The transfer molding temperature is usually 80 ° C. or higher, preferably 100 ° C. or higher, more preferably 120 ° C. or higher, and usually 300 ° C. or lower, preferably 250 ° C. or lower, more preferably 200 ° C. or lower. The molding time is usually 3 seconds or more, preferably 5 seconds or more, more preferably 10 seconds or more, and usually 1200 seconds or less, preferably 900 seconds or less, more preferably 600 seconds or less.

Any molding method can be post-cured as necessary. The post cure temperature is, for example, 100 ° C. or higher, preferably 150 ° C. or higher, more preferably 200 ° C. or higher, and 300 ° C. or lower, preferably 250 ° C. or lower, more preferably 200 ° C. or lower. The post-cure time is, for example, 3 minutes or more, preferably 5 minutes or more, more preferably 10 minutes or more, and 24 hours or less, preferably 10 hours or less, more preferably 5 hours or less.

[Experimental result]
<Trial manufacture of silicone composition and evaluation of light diffusibility>
A sheet is prepared from a silicone composition in which fumed silica is dispersed as an ultrafine filler in a silicone polymer, and spherical silica and spherical silicone resin are dispersed as micron-sized fillers. Evaluated as an indicator.

  As raw materials for the silicone polymer, silicone A (vinyl group content: 0.3 mmol / g, viscosity: 5000 mPa · s) in which a platinum complex catalyst is dispersed, and silicone B (hydrosilyl group content: 4.2 mmol / g, viscosity: 40 mPa · s) and silicone C containing an alkynyl group as a curing retarder (vinyl group content: 0.2 mmol / g, alkynyl group content: 0.3 mmol / g, viscosity: 1000 mPa · s), a weight ratio of 9: Liquid silicone having a viscosity of 3500 mPa · s obtained by mixing at 1: 0.1 was used. Here, silicone A, silicone B, and silicone C are all silicones that do not contain a phenyl group.

As the fumed silica, hydrophobic fumed silica (BET specific surface area: 140 ± 25 m ² / g, average primary particle diameter: about 12 nm) surface-treated with a trimethylsilyl group was used.
As the spherical silica, a spherical fused silica having a specific surface area: 2.2 m ^{2 /} g and d50: 4.9 μm was used.
As the spherical silicone resin, true spherical polymethylsilsesquioxane particles having a specific surface area of 20 m ² / g and an average particle size of 6.0 μm were used.

  In preliminary examination, it was visually confirmed that the uncured silicone composition obtained by mixing the above liquid silicone with the above fumed silica and spherical silicone resin was transparent at room temperature and became cloudy when heated. This suggests that the refractive index of the liquid silicone (lower than the refractive index of fumed silica) is lower than that of the spherical silicone resin at room temperature, and that the difference becomes larger during heating. That is, when a spherical silicone resin (high refractive index light diffusing material) and liquid silicone (polymer binder) are used, the thermal expansion coefficient of the liquid silicone (polymer binder) is spherical silicone resin (high refractive index light diffusing material). Since the thermal expansion coefficient of the spherical silicone resin (high refractive index light diffusing material) decreases due to heating, the spherical silicone resin (high refractive index light diffusing material) and liquid silicone (polymer binder) This suggests that the difference in the refractive index of. Therefore, by using a light diffusing material having a low refractive index and a thermal expansion coefficient smaller than that of the polymer binder, the difference in refractive index between the liquid silicone (polymer binder) and the spherical silicone resin (high refractive index light diffusing material) can be reduced. It is considered that the resulting increase in light diffusivity can be offset by a decrease in light diffusivity due to a difference in refractive index between liquid silicone (polymer binder) and a low refractive index light diffusing material.

Thermosetting silicone compositions containing the above liquid silicone, fumed silica, spherical silica and spherical silicone resin in various mixing ratios shown in Table 1 were prepared and molded into a 1 mm thick sheet using a press molding machine. . The molding pressure was 10 kg / cm ² or less, and the curing conditions were 150 ° C. and 3 minutes. Table 1 also shows “whiteness index” (described later) measured for the obtained silicone composition sheet.

  The “whiteness index” of the silicone composition sheet was measured using a whiteness index measurement mode of a spectrocolorimeter SPECTROTOPOMETER CM-2600d manufactured by Konica Minolta Optics. That is, in the same manner as when measuring the whiteness index defined by ASTM E313-73, the “whiteness index” of the silicone composition sheet was measured when the whiteness index of the standard white plate for calibration was 100. .

During measurement, the back side of the sheet (the side that is not the incident side of the evaluation light) is placed in the environment so that the evaluation light that has not been diffused inside the sheet (evaluation light that has passed through the sheet) is emitted into the environment. Released inside.
Strictly speaking, the “whiteness index” of the silicone composition sheet thus measured is different from the whiteness index of ASTM E313-73, which is an index for evaluating an essentially opaque object. However, it can be used as a useful index for the purpose of evaluating the light diffusibility of the silicone composition. This is because the higher the light diffusibility of the silicone composition, the greater the amount of evaluation light that is reflected by the sample sheet and returns to the incident side, and the value displayed as the “whiteness index” increases.

  Each sample shown in Table 1 can be regarded as a dispersion of spherical silica and spherical silicone resin as micron-sized fillers in a binder composition that is a mixture of a silicone polymer and fumed silica. From this point of view, the samples S01 to S09 have a constant binder composition (fumed silica content of 12 wt%) and a substantially constant binder composition content (silicone polymer volume ratio of 43 to 44). %), It can be said that the volume ratio of the spherical silica in the micron-sized filler (spherical silica and spherical silicone resin) is changed.

  FIG. 1 is a graph obtained by plotting the relationship between the “whiteness index” obtained from samples S01 to S09 and the volume ratio of spherical silica in the micron-sized filler. As can be seen from FIG. 1, the “whiteness index” increases linearly as the volume ratio of spherical silica in the micron-size filler increases. This indicates that mainly spherical silica acts as a light diffusing material.

  Also in samples S10 to S14, the volume ratio of the spherical silica in the micron-size filler (spherical silica and spherical silicone resin) was changed with the binder composition constant and the binder composition content substantially constant. Yes. However, the content of fumed silica in the binder composition is set to 16 wt%, which is higher than those of the samples S01 to S09.

Samples S15 and S16 have the same volume ratio of the silicone polymer and the volume ratio of spherical silica in the micron-size filler as sample S14, but the fumed silica content in the binder composition is 18 wt% and 20 wt%, respectively. %, Which is higher than Sample S14 (16 wt%).
FIG. 2 is an additional plot of the results of samples S10 to S16 with respect to the graph of FIG. It can be seen from FIG. 2 that the relationship between the “whiteness index” in samples S10 to S16 and the volume ratio of spherical silica in the micron-sized filler is substantially the same as that in samples S01 to S09. This result indicates that fumed silica has substantially no effect on the light diffusibility of the silicone composition.

<Prototype and evaluation of wavelength conversion component>
(Prototype example 1)
A flat plate-shaped wavelength conversion component was prepared by press molding using a curable silicone composition to which a phosphor was added based on the composition of sample 05 (“whiteness index” was 18.2). Was combined with a blue LED to produce a white light emitting device having a correlated color temperature of about 4000K. The phosphors used were yellow phosphor YAG, green phosphor β sialon, and red phosphor SCASN. The composition of the curable silicone composition was as follows, and the phosphor content was 4.0 wt%.

YAG ... 1.01g
Beta sialon ... 2.35g
SCASN ... 0.64g
Liquid silicone ... 32.5g
Fumed silica ... 4.4g
Spherical silica ... 14.8g
Spherical silicone resin 44.3g
The white light emitting device obtained had a color rendering index (Ra) of 82.

(Prototype example 2)
A flat plate-shaped wavelength conversion component was prepared by a press molding method using a curable silicone composition to which a phosphor was added based on the composition of sample 09 (“whiteness index” was 23.9). Was combined with a blue LED to produce a white light emitting device having a correlated color temperature of about 4000K. The phosphor used was the same as in Prototype Example 1. The composition of the curable silicone composition was as follows, and the phosphor content was 3.5 wt%.

YAG ... 0.88g
β Sialon 2.06g
SCASN ... 0.56g
Liquid silicone ... 32.0g
Fumed silica ・ ・ ・ 4.3g
Spherical silica ... 19.8g
Spherical silicone resin 40.4g
The white light emitting device obtained had a color rendering index (Ra) of 82. The brightness of this white light emitting device was substantially the same as that obtained in Prototype Example 1.

(Prototype example 3)
From the curable silicone composition obtained by mixing the same liquid silicone, fumed silica, spherical silica and spherical silicone as used in the above experiment, a fluorescent material having a diameter of 60 mm and a thickness of 1 mm (design value) by a liquid injection molding method. A disc containing no body was prepared. The composition of the curable silicone composition is as follows.

Liquid silicone ... 350g
Fumed silica ... 67g
Spherical silica ... 145g
Spherical silicone resin ... 438g
The results of viscosity measurement of this curable silicone composition are shown in Table 2 below.

The mold temperature during molding is in the range of 150 to 200 ° C, the filling time into the mold is 0.1 second to 1 second, and the resin curing time in the mold is between 10 seconds to several minutes. The pressure was adjusted between 0.5 and 2 t.
Two sheets were selected from the manufactured disks and the thicknesses thereof were measured at five locations. The thickness was 1.08 to 1.12 mm, and the average value was 1.09 mm. In addition, when three pieces were selected from the manufactured disks and the “whiteness index” and the diffuse reflectance at a wavelength of 450 nm were measured, the “whiteness index” was 19.7, 19.4, and 19.3. The diffuse reflectance was 16.9, 16.5 and 16.7.

(Prototype example 4)
From a curable silicone composition containing a YAG phosphor prepared using the same liquid silicone, fumed silica, spherical silica and spherical silicone used in the above experiment, a diameter of 60 mm and a thickness of 1 mm (designed) by a liquid injection molding method. Value) disk-shaped wavelength conversion component. The composition of the curable silicone composition is as follows.

YAG ... 62g
Liquid silicone ... 329g
Fumed silica ... 72g
Spherical silica ... 132g
Spherical silicone resin 405g
The results of viscosity measurement of this curable silicone composition are shown in Table 2 above.

The molding conditions were adjusted in the same manner as in Prototype Example 3 above. As a result, a molded product having a Shore D hardness of 36 could be obtained.
Although there was a variation in thickness between the produced wavelength conversion components, the average value of the film thickness measured at three in-plane positions in one sheet was in the range of 0.97 to 0.99 mm. Looking at the 18 wavelength conversion components, as shown in Table 3 below, the difference between the maximum value and the minimum value of the film thickness at three locations was 3% or less.

Table 3 also shows the correlated color temperature and xy chromaticity coordinate values of each of the 18 wavelength conversion components when a white light emitting device is configured in combination with a blue LED. ing. Parts (including blue LEDs) other than the wavelength conversion component used when configuring the white light emitting device are the same. As shown in Table 3, the correlated color temperature was in the range of 4007 to 4024K, and the variation range of the chromaticity coordinate value was 0.001 in the x-axis direction and 0.002 in the y-axis direction.

[Other Disclosures]
In addition, the following invention is disclosed.
(F1) A resin containing a binder, a phosphor and a spherical filler dispersed in the binder, wherein the spherical filler has a median diameter of 1 to 30 μm, and the content of the spherical filler is 30 to 90 Vol% A method for producing a wavelength conversion component, comprising a step of injection molding or transfer molding of a composition.
(F2) The production method according to (f1), wherein the resin composition is a liquid resin composition having thermosetting properties.
(F3) The production method according to (f2), wherein the resin composition contains liquid silicone. (F4) The production method according to any one of (f1) to (f3), wherein the spherical filler includes at least one selected from spherical silica and spherical silicone resin.
(F5) The production method according to any one of (f1) to (f3), wherein the spherical filler includes spherical silica having a specific surface area of 1 to 10 m ² / g.
(F6) In the said wavelength conversion component, the manufacturing method in any one of said (f1)-(f5) in which at least one part of the said spherical filler acts as a light-diffusion material.
(G1) A binder, a phosphor dispersed in the binder, and a spherical filler are contained, the median diameter of the spherical filler is 1 to 30 μm, and the content of the spherical filler is 30
The resin composition for wavelength conversion components which is -90Vol%.
(G2) The resin composition according to (g1), which is a liquid resin composition having thermosetting properties.
(G3) The resin composition according to (g2), containing a liquid silicone.
(G4) The resin composition according to any one of (g1) to (g3), wherein the spherical filler includes at least one selected from spherical silica and spherical silicone resin.
(G5) The resin composition according to any one of (g1) to (g3), wherein the spherical filler includes spherical silica having a specific surface area of 1 to 10 m ² / g.
(G6) The resin composition according to any one of (g1) to (g5), wherein at least a part of the spherical filler acts as a light diffusing material.

Claims (9)

  A wavelength conversion component comprising a polymer composition in which a phosphor and two or more kinds of light diffusing materials having different refractive indexes are dispersed in a polymer binder, wherein the light diffusing material has a higher refractive index than the light diffusing material. When the material is a light diffusing material having a high refractive index and the light diffusing material having a lower refractive index among the light diffusing materials is a light diffusing material having a low refractive index, the refractive index of the polymer binder at room temperature is A wavelength conversion component for a semiconductor light-emitting device, which is lower than a refractive index of a light diffusing material having a high refractive index and higher than a refractive index of the light diffusing material having a low refractive index.   The wavelength conversion component according to claim 1, wherein a thermal expansion coefficient of the polymer binder is higher than a thermal expansion coefficient of the light diffusing material having a high refractive index and a thermal expansion coefficient of the light diffusing material having a low refractive index.   The wavelength conversion component according to claim 1, wherein the polymer binder contains a silicone polymer.   The wavelength conversion component according to claim 1, wherein the polymer composition contains at least one selected from spherical silica and silicone particles as the light diffusing material.   The wavelength conversion component according to claim 4, wherein the polymer composition contains spherical silica as the light diffusing material having a high refractive index and silicone particles as the light diffusing material having a low refractive index.   The wavelength conversion component according to claim 4 or 5, wherein the polymer composition contains at least one of silicone particles and spherical silica that do not act as a light diffusing material.   At room temperature, at least one of a refractive index difference between the binder and the high refractive index light diffusing material and a refractive index difference between the binder and the low refractive index light diffusing material is 0.1 or less. The wavelength conversion component according to any one of 1 to 6.   The refractive index difference between the binder and the high refractive index light diffusing material and the refractive index difference between the binder and the low refractive index light diffusing material are both 0.1 or less at room temperature. The described wavelength conversion component.   A wavelength conversion component according to any one of claims 1 to 8 and a semiconductor light emitting device, wherein at least a part of light emitted by the semiconductor light emitting device is converted into light having a different wavelength by the wavelength conversion component. A semiconductor light emitting device.

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