JP7078509B2 - Complex, light emitting device and method for manufacturing complex - Google Patents

Description

The present invention relates to a complex, a light emitting device and a method for producing the complex.

In recent years, the development of a light emitting device that combines a semiconductor light emitting element such as an LED and a phosphor that absorbs a part of the light from the semiconductor light emitting element and converts the absorbed light into long wavelength wavelength conversion light to emit light. Is underway.

Patent Document 1 describes a wavelength conversion member including a phosphor that converts excitation light emitted from a semiconductor laser into fluorescence. Patent Document 1 discloses a technique of using glass as a sealing material for sealing the phosphor.

JP-A-2015-224299

While further miniaturization and higher output are required for semiconductor light emitting devices, further improvement in wavelength conversion efficiency is required for a complex containing a phosphor and a sealing material. The present inventor diligently studied the factors for improving the wavelength conversion efficiency of the complex, and found that the crystallinity of the encapsulant in the complex is closely related to the wavelength conversion efficiency of the complex. .. Patent Document 1 discloses a technique of coating phosphor particles with a coating layer containing α-type sialon for improving the wavelength conversion efficiency, but mentions the influence of the crystallinity of the encapsulant on the wavelength conversion efficiency. There is still room for development in improving the wavelength conversion efficiency of the composite.
Therefore, the present invention has been made in view of the above circumstances, and provides a technique for improving the wavelength conversion efficiency of a complex.

According to the present invention, the composite comprises an α-type sialon phosphor containing an Eu element and a sealing material for sealing the α-type sialon phosphor, wherein the sealing material contains silicon dioxide. Provided is a complex composed as a main component and in which at least a part of the silicon dioxide is crystallized.

Further, according to the present invention, there is provided a light emitting device having a light emitting element that emits excitation light and the above-mentioned composite that converts the wavelength of the excitation light.

Further, according to the present invention, the step of mixing the silicon dioxide powder and the α-type sialon phosphor powder containing at least Eu element as a light emitting center, and the mixture of the silicon dioxide powder and the α-type sialon phosphor powder. A method for producing a composite is provided, which comprises a step of heating the silicon dioxide at a temperature of 1300 ° C. or higher and 1450 ° C. or lower to form a crystal region in at least a part of silicon dioxide.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a technique for improving the wavelength conversion efficiency in a complex containing a phosphor and a sealing material.

It is sectional drawing which shows the structure of the light emitting device which concerns on embodiment. It is a schematic diagram of the apparatus for measuring the emission spectrum of a complex. It is an emission spectrum obtained by the complex of Example 1 and Comparative Example 1.

Hereinafter, embodiments of the present invention will be described in detail.

(Complex)
The complex according to the embodiment includes an α-type sialone phosphor containing an Eu element and a sealing material for sealing the α-type sialon phosphor. Hereinafter, each component constituting the complex will be described.

(Α-type Sialon phosphor)
The α-type sialon phosphor of the present embodiment has a general formula: (M) _x (Eu) _y (Si) _{12- (m + n)} (Al) _{m + n} (O) _n (N) _16-n (where M is Li). , Mg, Ca, Y and an α-type sialone phosphor containing an Eu element represented by at least one element containing Ca selected from the group consisting of lanthanide elements (excluding La and Ce).

The solid solution composition of α-type sialon is represented by m and n determined by x and y in the above general formula and the Si / Al ratio and O / N ratio associated therewith, and when the valence of M is a, ax + 2y = m, x + y ≦ 2, 0 <y <0.5, 0.3 ≦ m <4.5, 0 <n <2.25. In particular, when Ca is used as M, α-type sialon is stabilized in a wide composition range, and by substituting a part of it with Eu, which is the emission center, it is excited by light in a wide wavelength range from ultraviolet to blue, and from yellow. A phosphor exhibiting orange visible light is obtained.

In general, since α-type sialon has a second crystal phase different from that of α-type sialon or an amorphous phase that is inevitably present, the solid solution composition cannot be strictly defined by composition analysis or the like. The crystal phase of the α-type sialon is preferably an α-type sialon single phase, and other crystal phases may include β-type sialon, aluminum nitride, or a polytypoid thereof.

As a method for producing an α-type sialon phosphor, there is a method in which a mixed powder composed of a compound of silicon nitride, aluminum nitride and an infiltrated solid solution element is heated and reacted in a high temperature nitrogen atmosphere. In the heating step, some of the constituents form a liquid phase, and the substance moves to this liquid phase to form an α-type sialon solid solution. In the α-type sialon phosphor after synthesis, a plurality of equiaxed primary particles are sintered to form massive secondary particles. The primary particles in the present embodiment refer to the smallest particles having the same crystal orientation in the particles and being able to exist independently.

The lower limit of the average particle size of the α-type sialon phosphor is preferably 5 μm or more, more preferably 10 μm or more. The upper limit of the average particle size of the α-type Sialon phosphor is preferably 30 μm or less, more preferably 20 μm or less. The average particle size of the α-type Sialon phosphor is the dimension of the secondary particles. By setting the average particle size of the α-type Sialon phosphor to 5 μm or more, the transparency of the complex can be further enhanced. On the other hand, by setting the average particle size of the α-type Sialon phosphor to 30 μm or less, it is possible to suppress the occurrence of chipping when the complex is cut and processed with a dicer or the like.

Here, the average particle size of the α-type Sialon phosphor is the small particle size side in the volume-based particle size distribution obtained by measuring by the laser diffraction scattering type particle size distribution measurement method (LS13-320 manufactured by Beckman Coulter). It means the particle size of 50% of the accumulated passage amount (integrated passage ratio).

The lower limit of the content of the α-type sialon phosphor in the complex is preferably 14% by mass or more, more preferably 20% by mass or more. The upper limit of the content of the α-type sialon phosphor in the complex is preferably 60% by mass or less, more preferably 50% by mass or less. By setting the content ratio of the α-type sialon phosphor to 14% by mass or more, the wavelength conversion efficiency of the complex can be further improved. On the other hand, by setting the content ratio of the α-type sialon phosphor to 60% by mass or less, it is possible to improve the wavelength conversion efficiency while further increasing the transparency of the complex.

(Encapsulant)
The encapsulant of the present embodiment is composed mainly of silicon dioxide. Here, the fact that silicon dioxide is the main component means that the entire encapsulant contains 90% by mass or more of silicon dioxide. At least a part of silicon dioxide constituting the sealing material of the present embodiment is crystallized. The crystallinity of silicon dioxide can be evaluated by X-ray diffraction described later.

Since silicon dioxide has a crystalline region, the light emitted from the LED is scattered and easily absorbed by the α-type sialon phosphor. In other words, the crystalline region of silicon dioxide suppresses the escape of light in the complex. As a result, the amount of light incident on the α-type Sialon phosphor increases, and the wavelength conversion efficiency of the complex can be improved.

[Evaluation of crystallinity of silicon dioxide]
The crystallinity of silicon dioxide can be evaluated by X-ray diffraction. When silicon dioxide has a crystalline region, 2θ has the strongest peak in the range of 30 ° or more and 40 ° or less in the powder X-ray diffraction pattern of the composite measured using CuKα ray (1.54184 Å). Diffraction peaks appear in the range where 2θ is 21.7 ° or more and 22.7 ° or less, and 2θ is 26.5 ° or more and 27.5 ° or less. By confirming the diffraction peak, it can be confirmed that a crystal region exists in silicon dioxide.

It is preferable that the intensity of the diffraction peak appearing in the range where 2θ is 21.7 ° or more and 22.7 ° or less and 2θ is 26.5 ° or more and 27.5 ° or less is a predetermined value or more.

Specifically, in the powder X-ray diffraction pattern of the complex measured using CuKα ray (1.54184 Å), 2θ has the strongest peak in the range of 30 ° or more and 40 ° or less, and the peak intensity is 100. %, It is preferable that 2θ has a diffraction peak with a relative intensity of 1.2% or more in a range of 21.7 ° or more and 22.7 ° or less, and has a diffraction peak with a relative intensity of 1.5% or more. Is more preferable. When the relative intensity of the diffraction peak in the range where 2θ is 21.7 ° or more and 22.7 ° or less is 1.2% or more, the crystal region in silicon dioxide further improves the wavelength conversion efficiency of the complex. Can be sufficient area for.

Further, in the powder X-ray diffraction pattern of the complex measured using CuKα ray (1.54184 Å), 2θ had the strongest peak in the range of 30 ° or more and 40 ° or less, and the peak intensity was set to 100%. In this case, it is preferable to have a diffraction peak with a relative intensity of 0.8% or more in a range where 2θ is 26.5 ° or more and 27.5 ° or less, and it is more preferable to have a diffraction peak with a relative intensity of 1.2% or more. preferable. When the relative intensity of the diffraction peak in the range where 2θ is 26.5 ° or more and 27.5 ° or less is 0.8% or more, the crystal region in silicon dioxide further improves the wavelength conversion efficiency of the complex. Can be sufficient area for.

Here, the crystallinity of such silicon dioxide is indexed by the relative intensity of the diffraction peak. In the present embodiment, for example, the type and blending amount of the component containing silicon dioxide constituting the encapsulant, the encapsulation method of the α-type sialon phosphor with the encapsulant containing silicon dioxide as the main component, and the like are appropriately selected. Therefore, it is possible to control the relative intensity of the diffraction peak. Among these, for example, the condition of applying pressure in the solid phase when encapsulating the α-type sialon phosphor with the encapsulant containing silicon dioxide as the main component sets the relative intensity of the diffraction peak within the desired numerical range. It is mentioned as an element to do.

[Other components in the complex]
The complex may contain other components than the α-type sialone phosphor and silicon dioxide. Other components include one or more first transition metals selected from the group consisting of iron, cobalt, and nickel. The lower limit of the content of the first transition metal in the complex is preferably 0.1 ppm or more, more preferably 0.5 ppm or more, still more preferably 1 ppm or more. The upper limit of the content of the first transition metal in the complex is preferably 40 ppm or less, more preferably 30 ppm or less, still more preferably 20 ppm or less. Here, the content of the first transition metal in the complex means the content of the first transition metal as an element, and the existence form of the first transition metal does not matter.
By setting the lower limit of the content of the first transition metal in the complex to 0.1 ppm or more, cracks are generated in the complex, and chipping is performed when the complex is cut with a dicer or the like. It is possible to improve the wavelength conversion efficiency while suppressing the occurrence of. Further, by setting the upper limit of the content of the first transition metal in the complex to 40 ppm or less, the wavelength conversion efficiency can be improved. It is presumed that this is because the light passing through the complex is suppressed from being absorbed by the first transition metal, so that the amount of light whose wavelength is lengthened by the α-type sialon phosphor increases.

[Porosity of complex]
The porosity of the complex is preferably 8% or less, more preferably 5% or less. By setting the porosity of the complex to 8% or less, it is possible to suppress the deterioration of the translucency of the complex. Further, by improving the light scattering property, the amount of light absorbed by the α-type sialon phosphor can be increased, and the wavelength conversion efficiency of the complex can be improved.

[Wavelength conversion light of complex]
When the complex is irradiated with blue light having a wavelength of 455 nm, the peak wavelength of the wavelength conversion light emitted from the complex is preferably 585 nm or more and 605 nm or less. According to this, when a composite is combined with a light emitting element that emits blue light, it is possible to obtain a light emitting device that emits an amber color having high brightness.

(Manufacturing method of complex)
The method for producing the composite according to the embodiment includes a step (1) of mixing silicon dioxide powder and α-type sialon phosphor powder containing at least Eu element as a light emitting center, and silicon dioxide powder and α-type sialon phosphor. It has a step (2) of heating a mixture with powder at 1300 ° C. or higher and 1450 ° C. or lower to form a crystal region in at least a part of silicon dioxide.

In the step (1), the content of the first transition metal element in the silicon dioxide powder used as a raw material is preferably 40 ppm or less. Here, the first transition metal element is one or more selected from the group consisting of iron, cobalt, and nickel. By setting the content of the first transition metal element in the silicon dioxide powder within the above range, the wavelength conversion efficiency of the complex can be further improved. The silicon dioxide powder used as a raw material is preferably amorphous in an amount of 80% by mass or more, and more preferably amorphous in an amount of 90% by mass or more. By setting the proportion of amorphous material in the silicon dioxide powder used as a raw material within the above range, it is possible to produce a dense composite by heating it at a lower temperature, so that the wavelength conversion efficiency of the α-type sialon fluorescent substance can be improved. It can be suppressed from being damaged.

In the step (2), it is preferable to pressurize the mixture of the silicon dioxide powder and the α-type sialon phosphor powder in a pressure range of 5 MPa or more and 80 MPa or less using a pressurizing device such as a press machine, preferably 10 MPa or more and 70 MPa or less. It is more preferable to pressurize in the pressure range. This makes it possible to easily form a crystal region in silicon dioxide. By adjusting the heating temperature and the pressurizing temperature in the step (2), the ratio of the crystal region in the silicon dioxide can be controlled.

After the step (2), the complex can be produced according to the embodiment by slowly cooling to room temperature and depressurizing.

(Light emitting device)
FIG. 1 is a schematic cross-sectional view showing the structure of the light emitting device according to the embodiment. As shown in FIG. 1, the light emitting device 10 includes a light emitting element 20, a substrate 30, a dam 40, a sealing material 50, and a complex 80. It is a chip-on-board (COB) type light emitting device in which a light emitting element 20 is mounted on a substrate 30 having wiring (not shown).
The substrate 30 is an aluminum substrate having an insulating film such as an anodic oxide film of aluminum formed on the surface thereof. The substrate 30 is provided with a dam 40 that surrounds a predetermined region on the substrate 30. The shape of the dam 40 when the substrate 30 is viewed in a plan view is, for example, an annular shape. The dam 40 is preferably transparent.

The light emitting element 20 is mounted inside the dam 40 on the substrate 30. The light emitting element 20 is a semiconductor element that emits excitation light. As the light emitting element 20, an LED chip that generates light having a wavelength of 300 nm or more and 500 nm or less, which corresponds to blue light from near-ultraviolet light, can be used. The element electrode (not shown) of the light emitting element 20 is electrically connected to a connection terminal (not shown) exposed inside the dam 40 on the substrate 30 by a bonding wire (not shown).
The sealing material 50 is filled inside the dam 40, and the light emitting element 20 is sealed by the sealing material 50. The sealing material 50 is formed of a transparent resin material such as an epoxy resin or a silicone resin.

The complex 80 is located above the light emitting element 20 and is installed on the dam 40 and the encapsulant 50. The complex 80 is a plate-shaped wavelength conversion member that lengthens the wavelength of the excitation light emitted from the light emitting element 20. As the composite 80, the above-mentioned composite is used, and the α-type sialon phosphor 82 containing silicon dioxide as a main component and Eu element contained in the encapsulant 84 in which a part of the silicon dioxide is crystallized is dispersed. ing. The light emitting device 10 emits a mixed color of the light of the light emitting element 20 and the light generated from the α-type sialon phosphor 82 that is excited by absorbing the light of the light emitting element 20.

In the light emitting device 10, the outer surface of the complex 80 is the light emitting surface. That is, the complex 80 is arranged between the light emitting element 20 and the light emitting surface. When the peak value of the excitation light emitted from the light emitting element 20 on the light emitting surface is P1 and the peak value of the wavelength conversion light obtained by converting the wavelength of the excitation light by the composite 80 is P2, the intensity ratio P1 / P2 is 0. It is preferably .06 or less. According to this, the color of the light emitted from the light emitting device 10 can be brought close to the color of the wavelength conversion light. For example, when the wavelength conversion light is amber, the light emitted from the light emitting device 10 can also be amber.

Although the embodiments of the present invention have been described above, these are examples of the present invention, and various configurations other than the above can be adopted.

Hereinafter, the present invention will be described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

(Example 1)
The composite of Example 1 was obtained by dispersing the α-type Sialon fluorescent powder in a sealing material (matrix) in which a part of silicon dioxide was crystallized. A specific method for producing the complex of Example 1 will be described below.

As raw materials for the composite of Example 1, SiO ₂ powder (manufactured by Denka Co., Ltd., FB-5SDC grade) and Ca-α type Sialon fluorescent powder (manufactured by Denka Co., Ltd., Aron Bright / YL-600B grade, average particle size). : 15 μm) was used. Weighed 4.354 g of SiO ₂ powder and 2.723 g of Ca-α type sialon phosphor powder, and dry-mixed them with an agate mortar. The raw material after mixing was passed through a sieve of a nylon mesh having an opening of 75 μm to obtain a raw material mixed powder.

About 7 g of the raw material mixed powder was filled in a carbon die having an inner diameter of 30 mm in which a carbon lower punch was set, a carbon upper punch was set, and the raw material powder was sandwiched. A carbon sheet (GRAFOIL manufactured by GraTech) having a thickness of 0.127 mm was set between the raw material mixed powder and the carbon jig to prevent sticking.

The hot press jig filled with this raw material mixed powder was set in a multipurpose high temperature furnace (manufactured by Fuji Dempa Kogyo Co., Ltd., High Multi 5000) of a carbon heater. The inside of the furnace was evacuated to 0.1 Pa · G or less, and the upper and lower punches were pressurized with a press pressure of 15 MPa while maintaining the reduced pressure state. While maintaining the pressurized state, the temperature was raised from room temperature at a rate of 20 ° C. per minute, nitrogen gas was introduced into the furnace at 800 ° C., and the atmospheric pressure in the furnace was set to 0.1 MPa · G. After the introduction of nitrogen gas, the temperature was raised to 1375 ° C. at a rate of 5 ° C. per minute and maintained at 1375 ° C. for 15 minutes.
After that, the temperature is lowered to room temperature at a rate of 5 ° C. A disk-shaped composite having a diameter of 0.23 mm was obtained.

The bulk density of the complex of Example 1 was measured by a method according to JIS-R1634: 1998 and found to be 2.44 g / cm ³ . The true density of the complex was measured by the following method. First, the complex prepared under the same conditions was crushed in an agate mortar, and the whole amount was passed through a sieve having an opening of 45 μm. The true density of this pulverized powder was measured with a dry densitometer (Acupic II 1340-10CC, manufactured by Shimadzu Corporation). The true density obtained was 2.58 g / cm ³ . The relative density (bulk density / true density) of the complex of Example 1 was 94.6%, and the porosity was 5.4%.

(Comparative Example 1)
The composite of Comparative Example 1 was obtained by dispersing the α-type Sialon fluorescent powder in a sealing material (matrix) in which the entire silicon dioxide was in an amorphous state. The method for producing the complex of Comparative Example 1 is the same as the method for producing the complex of Example 1 except that the SiO ₂ raw material powder is an SFP-30M grade manufactured by Denka.

The bulk density and true density of the complex of Comparative Example 1 were measured in the same manner as in the method for measuring the bulk density and true density of the complex of Example 1. As a result, the bulk density and the true density of the complex of Comparative Example 1 were 2.34 g / cm ³ and 2.60 g / cm ³ , respectively. The relative density (bulk density / true density) of the complex of Comparative Example 1 was 90.0%, and the porosity was 10.0%.

[Crystal structure analysis]
Crystal structure analysis of the complex of Example 1 and Comparative Example 1 was carried out using an X-ray diffractometer (product name: Ultima-IV, manufactured by Rigaku Co., Ltd.).
From the obtained powder X-ray diffraction pattern, the crystallinity was evaluated by the following procedure.
(1) In the powder X-ray diffraction pattern measured using CuKα ray (1.54184 Å), the peak intensity of the strongest peak in the powder X-ray diffraction pattern in which 2θ is in the range of 30 ° or more and 40 ° or less is P0. did.
(2) The peak intensities P1 of the peaks in which 2θ was in the range of 21.7 ° or more and 22.7 ° or less and the peak intensities P2 of the peaks in which 2θ was in the range of 26.5 ° or more and 27.5 ° or less were obtained. The relative intensities (%) of the peak intensities P1 and the peak intensities P2 when the peak intensities P0 were set to 100% were obtained.

[Measurement of quantum efficiency of complex]
The quantum efficiency of the complex was evaluated by a quantum efficiency measurement system (QE-2100HMB manufactured by Otsuka Denshi Co., Ltd.) having a system for independently evaluating the reflected fluorescence and the transmitted fluorescence of the composite processed into a disk shape. The excitation light was blue light having a wavelength of 455 nm, and the absorption rate, the internal quantum efficiency, and the external quantum efficiency of the disk-shaped complex were calculated. Table 1 shows the measurement results of the quantum efficiency of the complex.

[Evaluation of emission characteristics]
FIG. 2 is a schematic diagram of an apparatus for measuring the emission spectrum of a complex. An aluminum substrate 100 having a recess 102 formed therein was prepared, and a blue LED 110 was mounted in the recess 102 as a blue light emitting light source to form a chip-on-board type (COB type) LED package. The diameter φ of the bottom surface of the recess 102 was 13.5 mm, and the diameter φ of the opening of the recess 102 was 16 mm. A circular complex 120 was installed above the blue LED 110 so as to close the recess 102.

The transmitted light when the blue LED 110 was turned on was measured using a total luminous flux measurement system (HalfMoon / φ1000 mm integrating sphere system, manufactured by Otsuka Electronics Co., Ltd.). The emission spectra obtained from the complex of Example 1 and Comparative Example 1 are shown in FIG. The peak wavelength of the emission spectrum was 600 nm. The emission intensity on the vertical axis of FIG. 3 is a relative value when the maximum emission intensity of Example 1 is 100.

Further, as can be seen from FIG. 2, in both Example 1 and Comparative Example 1, a spectrum derived from the transmitted light of the blue LED 110 was observed near a wavelength of 450 nm. The maximum value of the emission intensity of the wavelength 445 nm or more and 465 nm or less when the maximum value of the emission intensity of the wavelength 595 nm or more and 605 nm or less in the emission spectrum was set to 1 was defined as the transmitted amount of blue light. Table 1 shows the evaluation results of the light emission characteristics.
In the device example of FIG. 2, the outer surface of the complex 120 is a light emitting surface, and the transmitted light of the blue LED 110 is the excitation light emitted from the light emitting surface. Further, the light having a wavelength of 595 nm or more and 605 nm or less is wavelength conversion light emitted from the light emitting surface. That is, the above-mentioned amount of transmitted blue light corresponds to the intensity ratio of the peak of the excitation light to the peak of the wavelength conversion light emitted from the light emitting surface.

10 Light emitting device 20 Light emitting element 30 Substrate 40 Reflector 50 First lead frame 60 Second lead frame 70 Bonding wire 80 Composite 82 α-type Sialon phosphor 84 Encapsulant 100 Aluminum substrate 110 Blue LED
120 complex

Claims (11)

An α-type sialon phosphor containing an Eu element, a sealing material for sealing the α-type sialon phosphor, and a sealant.
Is a complex containing
The encapsulant is a complex having silicon dioxide as a main component and having at least a part of the silicon dioxide crystallized. In the powder X-ray diffraction pattern measured using CuKα ray (1.54184 Å), when 2θ has the strongest peak in the range of 30 ° or more and 40 ° or less and the peak intensity is 100%, 2θ is The complex according to claim 1, which has a diffraction peak with a relative intensity of 1.2% or more in the range of 21.7 ° or more and 22.7 ° or less. In the powder X-ray diffraction pattern measured using CuKα ray (1.54184 Å), when 2θ has the strongest peak in the range of 30 ° or more and 40 ° or less and the peak intensity is 100%, 2θ is The complex according to claim 1 or 2, which has a diffraction peak with a relative intensity of 0.8% or more in the range of 26.5 ° or more and 27.5 ° or less. The complex according to any one of claims 1 to 3, wherein the porosity is 8% or less. The complex according to any one of claims 1 to 4, wherein the peak wavelength of the wavelength conversion light when irradiated with blue light having a wavelength of 455 nm is 585 nm or more and 605 nm or less. The complex according to any one of claims 1 to 5, wherein the α-type sialone phosphor has an average particle size of 5 μm or more and 30 μm or less. The complex according to any one of claims 1 to 6, wherein the complex contains 14% by mass or more and 60% by mass or less of the α-type sialone phosphor. A light emitting element that emits excitation light and
The complex according to any one of claims 1 to 7, which converts the wavelength of the excitation light, and the complex.
A light emitting device having. The complex is arranged between the light emitting element and the light emitting surface, and the complex is arranged.
The light emission according to claim 8, wherein the intensity ratio of the peak value of the excitation light to the peak value of the wavelength conversion light whose wavelength of the excitation light is converted by the complex emitted from the light emitting surface is 0.06 or less. Device. A step of mixing silicon dioxide powder and α-type sialon phosphor powder containing at least Eu element as a light emitting center,
A step of heating a mixture of the silicon dioxide powder and the α-type sialon phosphor powder at 1300 ° C. or higher and 1450 ° C. or lower to form a crystal region in at least a part of silicon dioxide.
A method for producing a complex. The method for producing a complex according to claim 10, wherein 80% by mass or more of the silicon dioxide powder is amorphous.

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