WO2021024914A1

WO2021024914A1 - Fluorescent particle-dispersed glass and light-emitting device

Info

Publication number: WO2021024914A1
Application number: PCT/JP2020/029297
Authority: WO
Inventors: 多々見　純一; なつみ虎瀬; 拓実高橋
Original assignee: 地方独立行政法人神奈川県立産業技術総合研究所
Priority date: 2019-08-02
Filing date: 2020-07-30
Publication date: 2021-02-11
Also published as: JP2021026105A; JP7376022B2

Abstract

In a fluorescent particle-dispersed glass (6) according to the present invention, glass is used as a matrix (3), and at least fluorescent particles (4) and a heat conductive filler (5) that includes boron nitride are dispersed in the matrix (3). The thermal conductivity of the fluorescent particle-dispersed glass (6) is preferably at least 2 W/(m·K) or higher. The boron nitride content is preferably 5 mass% or higher. Provided are a fluorescent particle-dispersed glass having both thermal conductivity and fluorescence, a method for producing the same, a light-emitting device, and a light-emitting system.

Description

Fluorescent particle dispersion glass and light emitting device

The present invention relates to fluorescent particle dispersed glass. The present invention also relates to a light emitting device provided with the phosphor particle dispersion glass.

Light emitting devices equipped with semiconductor light emitting elements such as light emitting diodes (LEDs: Light Emission Diodes) and laser diodes (LDs: Laser Diodes) are excellent in terms of low power consumption and long life, and are excellent for lighting devices and liquid crystal displays. It is used as a backlight for devices and a light source for laser devices. Among them, white LEDs are becoming widely used as alternative lighting for fluorescent lamps.

A white LED is known to emit white light by combining a light emitting diode, which is a primary light source, and a fluorescent member. As this fluorescent member, a molded product in which phosphor particles are dispersed in a resin has been developed. By using a resin as the matrix of the fluorescent member, the molding processability becomes excellent. However, since the temperature tends to be high due to the heat generated from the light emitting diode which is the primary light source and the heat generated by the energy conversion loss during the excitation-light emission process in the fluorescent member, the thermal conductivity is low and the heat resistance is low. There is a problem that the resin (matrix) deteriorates. This problem is particularly serious when using high power LEDs and lasers.

Therefore, as an alternative matrix to the resin, ceramics (Patent Document 1) in which phosphor particles are dispersed in a matrix composed of a sialone compound have been proposed. Further, a phosphor-dispersed inorganic glass plate having a 50% particle diameter D50 of highly thermally conductive substance particles equal to or larger than the plate thickness has been proposed (Patent Document 2).

When the above-mentioned Sialon is used as a matrix, for example, a high-temperature firing process at 1000 to 1500 ° C. is required for densification of the matrix, so that the dispersed phosphor particles are liable to deteriorate. In addition, it is necessary to exclude the combination in which the matrix and the phosphor particles react at a high temperature, which limits the applicable phosphor particles. On the other hand, the fluorescent member using glass as a matrix can be plated at a relatively low temperature.

International release 2018/38259 Japanese Unexamined Patent Publication No. 2014-22412

As mentioned above, glass has the advantage of being able to be plated at a relatively low temperature, as well as having strong mechanical strength and excellent transparency. On the other hand, glass has a drawback of low thermal conductivity. The above-mentioned Patent Document 2 discloses a phosphor-dispersed inorganic glass plate using aluminum nitride, but it is necessary to set the size of the highly thermally conductive substance particles and the thickness of the plate within a specific range, and the degree of freedom in design is high. However, improvement in thermal conductivity is also desired.

In particular, for light emitting devices for high output applications, as described above, it is possible to efficiently dissipate heat generated by the temperature rise of the light emitting diode and the laser diode itself and the energy conversion loss during the excitation-light emitting process. The development of phosphor particle dispersion glass having excellent thermal conductivity is eagerly desired.

Although the problems when used for white LEDs and the like have been described above, the same problems may occur for fluorescent particle dispersed glass in general.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a phosphor particle-dispersed glass having excellent thermal conductivity and a light emitting device.

[1]: Using glass as a matrix
At least the fluorescent particles and the thermally conductive filler are dispersed in the matrix.
Fluorescent particle-dispersed glass in which the thermally conductive filler contains boron nitride.
[2]: The phosphor particle-dispersed glass according to [1], which has a thermal conductivity of at least 2 W / (m · K) or more.
[3]: The average particle size of the boron nitride in the matrix determined from the maximum ferret diameter in the ISO 133831: 2012 image analysis method is 0.5 to 200 μm [1] or [2]. The phosphor particle dispersion glass according to.
[4]: The phosphor particle-dispersed glass according to any one of [1] to [3], wherein the boron nitride content is 5% by mass or more.
[5]: The phosphor particle-dispersed glass according to any one of [1] to [4], wherein the phosphor particles are nitride phosphor particles.
[6]: The phosphor particle-dispersed glass according to any one of [1] to [5], wherein the glass is a phosphate-based glass.
[7]: A semiconductor light emitting device that emits the first light,
A light emitting device provided with the phosphor particle dispersion glass according to any one of [1] to [6], which is installed on the emission light side of the semiconductor light emitting element and uses the first light as excitation light to emit the second light. ..

According to the present invention, it is possible to provide a phosphor particle-dispersed glass having excellent thermal conductivity and a light emitting device, which is an excellent effect.

The schematic cross-sectional view which shows an example of the light emitting device which concerns on this embodiment. A schematic cross-sectional view showing an example of a light emitting device according to a modified example. SEM image of the fluorescent particle dispersion glass of Example 1. XRD profiles of the fluorophore particle dispersed glasses of Example 1 and Comparative Examples 2 and 3. The emission / excitation spectrum of the phosphor particle-dispersed glass of Example 1.

Hereinafter, an example of an embodiment to which the present invention is applied will be described. Other embodiments are also included in the scope of the present invention as long as they are consistent with the gist of the present invention. In addition, the numerical value specified in the present specification is a value obtained by the method disclosed in the embodiment or the embodiment. The following description and drawings have been simplified as appropriate to clarify the description. In addition, matters necessary for the practice of the present invention not particularly mentioned in the present specification can be grasped as design matters of those skilled in the art based on the prior art in the art.

[Fluorescent particle dispersed glass]
The phosphor particle-dispersed glass according to the present embodiment comprises a glass sintered body in which glass is used as a matrix and at least phosphor particles and boron nitride are dispersed in the matrix. The shape of the phosphor particle-dispersed glass is, for example, a disk shape, a flat plate shape, a convex lens shape, a concave lens shape, a spherical shape, a hemispherical shape, a cube shape, a rectangular parallelepiped shape, a columnar shape such as a prism or a cylinder, or a tubular shape such as a prism or a cylinder. Can be mentioned. When applied to a white LED, for example, it is used by arranging it on the emission light side of a blue LED serving as an excitation light source.

In the phosphor particle dispersion glass, at least a part of the first light emitted from the semiconductor light emitting element or the like is absorbed by the phosphor particles as excitation light, and the second light is emitted. The phosphor particles in the present specification include not only so-called fluorescence-emitting particles but also phosphorescent particles. The first light refers to light having a specific wavelength or light in a specific band, and the first light may be of one type or a plurality of types. As an example of the case where there are a plurality of types, there is a case where a semiconductor light emitting device that emits the first light of blue light and a semiconductor light emitting element that emits the first light of ultraviolet light are provided. The second light refers to light emitted from the phosphor particles in which at least a part of the first light becomes excitation light of the phosphor particles. There may be one type or multiple types of second light. As an example of the case where there are a plurality of types, there is a case where a plurality of types of phosphor particles having different emission bands are dispersed in the same phosphor particle dispersion glass. In addition, an embodiment in which phosphor particles having different emission bands are dispersed in different phosphor particle-dispersed glasses can also be exemplified.

When phosphor particle dispersion glass is used to obtain white light, for example, a phosphor particle that emits red light by blue light that is excitation light and a phosphor particle that emits green light by blue light that is excitation light are used. It is contained in the phosphor particle-dispersed glass. Further, the phosphor particle-dispersed glass is assumed to have a transmittance of transmitting blue light which is excitation light and which does not contribute to excitation. As a result, the blue light transmitted through the phosphor particle-dispersed glass and the red light and green light emitted from the phosphor particle-dispersed glass are mixed to obtain white light.
In another example, phosphor particles that use ultraviolet light or purple light as excitation light and emit blue light on the phosphor particle dispersion glass, and phosphor particles that emit red light by the excitation light of ultraviolet light or purple light. And phosphor particles that emit green light by excitation light of ultraviolet light or purple light. As a result, the blue light, red light, and green light emitted from the phosphor particle-dispersed glass are mixed. As a result, white light can be obtained from the phosphor particle-dispersed glass of the present embodiment. In this case, in addition to the design in which a part of the excitation light passes through the phosphor particle-dispersed glass, the design may be such that the entire excitation light is absorbed by the phosphor particle-dispersed glass.

In the phosphor particle-dispersed glass of the present embodiment, it is preferable that the phosphor particles are uniformly present throughout the glass from the viewpoint that the fluorescence emission is uniform and the total transmittance of the excitation light is uniform. .. By doing so, the excitation light transmitted through the phosphor particle-dispersed glass and the fluorescence emitted from the phosphor particle-dispersed glass are mixed, and it is easy to adjust the color of the emitted light of the phosphor particle-dispersed glass. It becomes. Instead of the above aspect, a concentration gradient may be provided in the distribution of the phosphor particles, or a phosphor particle-dispersed glass containing different phosphor particles depending on the region may be used. Such a phosphor particle-dispersed glass can be easily obtained by changing the process during the manufacturing process. It is also possible to bond different types of phosphor particle dispersed glass.

A suitable example of the thickness of the phosphor particle-dispersed glass may vary depending on the application, but is, for example, 0.01 to 10 mm. The refractive index (nd) of the phosphor particle-dispersed glass can be appropriately designed depending on the medium. The refractive index of the phosphor particle-dispersed glass is, for example, in the range of 1.40 to 1.90. An optical film may be provided on at least one of the entrance surface side and the exit surface side of the phosphor particle dispersion glass. For example, an antireflection film can be provided.

(matrix)
The glass to be used as a matrix is not particularly limited as long as it can disperse phosphor particles and boron nitride. Examples include phosphate-based glass, tellurite-based glass, borosilicate-based glass, and bismuthate-based glass. Examples of the phosphate-based glass include tin phosphate-based glass. The borosilicate based glass containing, by mass%, a SiO ₂ 30 ~ 85%, the _{_{_{_{Al 2 O 3 0 ~ 30%}}}} , B 2 O 3 0 ~ 50%, Li 2 O + Na 2 O + K 2 O 0 to 10 % And those containing 0 to 50% of MgO + CaO + SrO + BaO. The Suzurin salt-based glass, in mol%, a SnO 30 ~ _90%, include those containing from 1 to 70% P 2 _{O 5.} As the tellurite glass, in mol%, TeO ₂ is 50% or more, ZnO is 0 to 45%, RO (R is at least one selected from Ca, Sr and Ba) 0 to 50%, and La ₂ Examples thereof include those containing 0 to 50% of O ₃ + Gd ₂ O ₃ + Y ₂ O ₃ .

From the viewpoint of preventing deterioration of the phosphor particles and the reaction of the matrix component with the phosphor particles and / or boron nitride, the transition point of the glass matrix is preferably as low as possible, preferably 1000 ° C. or lower, and 750 ° C. The temperature is more preferably 600 ° C. or lower, and particularly preferably 550 ° C. or lower. The lower limit of the transition point of the glass is not particularly limited, but considering the mechanical strength and heat resistance of the phosphor particle-dispersed glass, it is preferably 250 ° C. or higher, more preferably 300 ° C. or higher, and 400 ° C. or higher. Is more preferable. From the viewpoint that firing at a low temperature (for example, 400 to 600 ° C.) is possible, the glass used as the matrix is particularly preferably phosphate-based glass, bismuth-based glass, or tellurite-based glass.

(Fluorescent particle)
According to the present embodiment, for example, by using phosphate-based glass, it is possible to sinter at a relatively low temperature, so that a wide variety of phosphor particles can be used. For example, beta sialon phosphor, KSF phosphor _{_{(K 2 SiF 6: Mn)}} , CASN, S-CASN, activated yttrium aluminum garnet (YAG) phosphor with cerium, it was activated with cerium Yttrium aluminum garnet (LAG-based phosphor, europium and / or chromium-activated nitrogen-containing calcium aluminosilicate (CaO-Al ₂ O ₃ -SiO ₂ ) -based phosphor, europium-activated silicate ((() Examples thereof include Sr, Ba) ₂ SiO ₄ ) -based phosphors. From the viewpoint of suppressing a decrease in emission intensity due to a temperature rise due to laser excitation or the like, nitride phosphor particles are preferable. The nitride phosphor particles are α. Examples thereof include a sialon fluorescent substance, a β sialon fluorescent substance, CASN, and S-CASN.

As the phosphor particles, nitride phosphor particles containing nitrogen in the phosphor composition are suitable. As a specific example, the nitride phosphor comprising strontium and silicon crystal phase _{_{_{(e.g., SCASN, Sr 2 Si 5 N}}} 8), a nitride phosphor containing calcium and silicon in the crystalline phase (e.g. SCASN, CASN, Cason), Crystallized nitride phosphors containing strontium, silicon and aluminum in the crystal phase (eg SCASN, Sr ₂ Si ₅ N ₈ ), barium, nitride phosphors containing silicon in the crystal phase (eg BSON), calcium, silicon and aluminum Nitride phosphors included in the phase (eg, SCASN, CASN, CASON) can be mentioned.
Other classifications of nitride phosphors include lanthanum nitrid silicates (eg LSN), alkaline earth metal nitrid silicates (eg Sr ₂ Si ₅ N ₈ ), alkaline earth metal nitrid silicates (CASN,). SCASSN, α-sialon, (Ca, Sr) AlSi ₄ N ₇ ) and the like can be mentioned.
More specifically,
Β-sialon which can be expressed by the following general formula;
Si _6-z Al _z _Oz N _8-z : Eu (0 <z <4.2 in the formula), α-sialon,
LSN expressed by the following general formula; Ln _x Si ₆ N _y M _z [1]
(In the formula [1], Ln represents one or more elements selected from rare earth elements excluding the element used as the activating element, M represents one or more elements selected from the activating elements, and x, y. , Z are values that independently satisfy the following equations.
2.7 ≦ x ≦ 3.3, 10 ≦ y ≦ 12, 0 <z ≦ 1.0)
CASN expressed by the following general formula; CaAlSiN ₃ : Eu,
SCASN; (Ca, Sr, Ba, Mg) AlSiN ₃ : Eu and / or (Ca, Sr, Ba) AlSi (N, O) ₃ : Eu, which can be expressed by the following general formula:
CASON which can be expressed by the following general formula; (CaAlSiN ₃ ) _1-x (Si ₂ N ₂ O) _x : Eu (0 <x <0.5 in the formula),
CaAlSi ₄ N ₇ ; Euy (Sr, Ca, Ba) 1-y: Al _{1 + x} Si _4-x O _x N _7-x (in the formula, 0 ≦ x <4, 0 ≦) can be expressed by the following general formula. y <0.2),
Sr ₂ Si ₅ N ₈ ; (Sr, Ca, Ba) ₂ Al _x Si _5-x O _x N _8-x : Eu (0 ≦ x ≦ 2 in the formula), which can be expressed by the following general formula.
BSON can be represented by the following general _{_{formula; M x Ba y (Sr,}} Ca, Mg, Zn) z L 6 O 12 N 2 ( where, M is Cr, Mn, Fe, lanthanide (La, Pm, Gd , Lu is excluded), L represents a metal element belonging to Group 4 or Group 14 of the periodic table containing Si, and x, y, and z have the following formulas independently. It is a value to be satisfied.
Examples thereof include phosphors such as 0.03 ≦ x ≦ 0.9, 0.9 ≦ y ≦ 2.95, and x + y + z = 3).
Among these phosphors, from the viewpoint that the brightness when sintered does not decrease, a nitride phosphor that does not contain oxygen as a constituent element (including oxygen that is inevitably mixed), that is, LSN, CaAlSiN ₃ , It is preferable to use a nitride phosphor such as SCASN, Sr ₂ Si ₅ N ₈ , β-sialon, and BSON.

The type of phosphor particles to be added is not particularly limited, and a plurality of types may be added depending on the purpose.

The content of the phosphor particles in the phosphor particle-dispersed glass includes the shape (thickness, etc.) of the phosphor particle-dispersed glass, the required transparency (total transmittance of excitation light), the fluorescence (fluorescence intensity, emission wavelength), and the like. It can be adjusted appropriately according to the quantum efficiency. If the content of the phosphor particles is too small, it is necessary to increase the thickness of the phosphor particle-dispersed glass in order to obtain a desired emission color, and the internal scattering of the phosphor particle-dispersed glass increases and the light extraction efficiency decreases. May be invited. On the other hand, if the content of the phosphor particles is too large, it is necessary to reduce the thickness of the phosphor particle-dispersed glass in order to obtain a desired emission color, and the mechanical strength of the phosphor particle-dispersed glass may decrease. ..

The average particle size of the phosphor particles in the matrix is not particularly limited, but is preferably 500 nm to 30 μm, preferably 1 μm to 10 μm, from the viewpoint of obtaining a good balance of excitation light transmission, good fluorescence characteristics, and dispersibility. Is more preferable. The average particle size of the phosphor particles in the matrix is determined by the maximum ferret diameter in the image analysis method based on ISO13383-1: 2012. The total transmittance of the phosphor particle-dispersed glass of the excitation light is preferably, for example, 10% or more in the optical path direction.

(Thermal conductive filler)
The phosphor particle-dispersed glass of the present embodiment contains boron nitride as a thermally conductive filler. By using boron nitride as the thermally conductive filler, a phosphor particle-dispersed glass exhibiting excellent thermal conductivity can be obtained. This is considered to be due to the high corrosion resistance of boron nitride. Examples of boron nitride include cubic boron nitride and hexagonal boron nitride (h-BN). In addition to the embodiment in which boron nitride is dispersed in the phosphor particle-dispersed glass in a non-oriented manner, it can be dispersed with orientation. h-BN has a plate-like particle shape and is known to exhibit high thermal conductivity in the plate surface direction (in-plane of ab or (002)) (usually, the thermal conductivity is 400 W / (usually, in-plane). m ・ K) degree). Therefore, from the viewpoint of efficiently increasing the thermal conductivity, it is preferable to use the h-BN oriented in the direction in which the thermal conductivity is desired to be increased. As will be described later, the orientation of h-BN can be imparted by uniaxial pressing in the manufacturing process. In addition, here, "aligned" includes an aspect in which the phosphor particle-dispersed glass is oriented to such an extent that anisotropy can be imparted to the thermal conductivity.

As the h-BN, in addition to being used as the primary particles, h-BN secondary particles in which h-BN is aggregated may be used. Further, boron nitride secondary particles sintered by heating may be used. It is also possible to increase the thermal conductivity isotropically by using h-BN secondary particles.

The content of boron nitride in the phosphor particle-dispersed glass is preferably 5% by mass or more, more preferably 10% by mass or more, and particularly preferably 30% by mass or more from the viewpoint of effectively imparting thermal conductivity. Further, from the viewpoint of increasing the density of the phosphor particle-dispersed glass, 80% by mass or less is preferable, 70% by mass or less is more preferable, and 50% by mass or less is further preferable.

The average particle size of boron nitride in the phosphor particle-dispersed glass obtained from the maximum ferret diameter in the ISO13383-1: 2012 image analysis method is preferably 0.5 to 200 μm from the viewpoint of high thermal conductivity. It is more preferably 1 to 150 μm, and even more preferably 3 to 100 μm. The average particle size of the phosphor particles in the phosphor particle-dispersed glass is determined as the maximum ferret diameter in the image analysis method based on ISO13383-1: 2012. The specific measurement method is the same as that for the phosphor particles.

In addition to boron nitride, metal oxides such as aluminum oxide, zinc oxide, titanium dioxide, beryllium oxide, magnesium oxide, nickel oxide, vanadium oxide, copper oxide, iron oxide, and silver oxide; quartz powder as thermal conductive fillers. , Silicon Carbide, Silicon Carbide, Mica, and other silicon compounds, and these can be used in combination with boron nitride.

When a resin is used as the matrix of the fluorescent member, the thermal conductivity is about 0.1 W / (m · K), and when glass is used, the thermal conductivity is about 1 W / (m · K) or less. In the present embodiment, the thermal conductivity can be increased by adding boron nitride. The thermal conductivity of the phosphor particle-dispersed glass of the present embodiment is preferably at least 1.2 W / (m · K) or more, more preferably, from the viewpoint of making the thermal conductivity more excellent. It is preferably 2 W / (m · K) or more, and more preferably 2.3 W / (m · K) or more. When the thermal conductivity of the phosphor particle-dispersed glass has anisotropy, the thermal conductivity in the direction of the highest thermal conductivity is preferably 10 W / (m · K) or more, more preferably 20 W / K. It is (m · K) or more, and more preferably 30 W / (m · K) or more.
The higher the thermal conductivity, the more preferable, but considering the transparency and denseness of the phosphor particle-dispersed glass, the upper limit thereof is usually 100 W / (m · K) or less. The thermal conductivity referred to in the present specification means the thermal conductivity of the fluorophore particle dispersed glass measured by the xenon flash method, and specifically, the value measured by the method described in the examples. ..

[Manufacturing method of phosphor particle dispersed glass]
Next, an example of the method for producing the fluorescent particle-dispersed glass according to the present embodiment will be described, but the method for producing the fluorescent particle-dispersed glass of the present invention is not limited to the following.

The method for producing phosphor particle-dispersed glass of the present embodiment includes a step of mixing at least phosphor particles, boron nitride, and a raw material powder of a matrix to obtain a mixture, and sintering this mixture. The sintering temperature at the time of production may be a temperature lower than the softening point of the glass powder as long as a glass sintered body can be obtained, but sintering is performed at a temperature equal to or higher than the softening point of the raw material powder of the matrix. Is preferable. According to the manufacturing method of the present embodiment, it is possible to manufacture a phosphor particle-dispersed glass capable of achieving both excellent properties such as mechanical strength and transparency of the glass and thermal conductivity. The details will be described below.

Each raw material may be crushed / crushed as necessary before mixing. The method for obtaining the mixture is not particularly limited, and can be obtained, for example, through a dry or / and wet step. In the case of the dry method, for example, there is a method in which at least phosphor particles, boron nitride and matrix raw material powder are placed in a mortar and mixed. At this time, a dispersant may be added. From the viewpoint of homogenizing the powder size of the mixture, two or more sieves having different mesh sizes may be used stepwise to obtain a mixture having a predetermined particle size. In the case of wet mixing, the slurry is prepared by mixing with a solvent (ethanol, etc.) using a ball mill or the like, and then the solvent is distilled off to obtain a primary molded body, and the primary molded body is fired. An example is a method for obtaining a sintered body. Further, the sintering process and the solvent distilling process may be performed at the same time without forming the primary molded body. Further pressure may be applied if necessary. The pressurization may be isotropic or anisotropic (eg, uniaxial). When imparting anisotropy, a method of uniaxial pressing is convenient.

The firing temperature can be arbitrarily set from the viewpoint of densifying while suppressing the reaction between the phosphor and the glass. For example, in the case of phosphate-based glass, the temperature is preferably in the range of 400 ° C to 550 ° C. From the viewpoint of sufficient densification, for example, a pressure of about 0.5 to 100 MPa can be applied. When pressure is applied, it is more preferably 1 to 50 MPa, further preferably 5 to 30 MPa. By setting the value to 0.5 to 100 MPa, high density due to the viscous flow of glass can be promoted. A known method can be applied as a means for applying pressure. Although it may be isotropically pressurized or anisotropically pressurized, uniaxial pressurization is preferable from the viewpoint of convenience of the apparatus and imparting orientation to boron nitride. When pressurizing in one direction, for example, a hot press method can be used. By imparting the orientation of boron nitride, it is possible to impart anisotropy to the thermal conductivity. Therefore, it is particularly suitable for applications that require anisotropic thermal conductivity. When pressurizing isotropically, pressurization by hydrostatic pressure is preferable. The pressurization time varies depending on the mechanism of the chemical reaction contributing to densification and the pressure, but is preferably 1 to 60 min. When pressurization and heating are used together, they may be simultaneous or separate, and the process procedures can be arbitrarily combined.

In order to increase the transparency of the phosphor particle-dispersed glass, it is preferable to remove pores that are light scattering sources as much as possible. From the viewpoint of increasing the transparency and effectively increasing the luminous efficiency, the density of the phosphor particle-dispersed glass is preferably 2.3 g / cm ³ or more. Here, the density is obtained by dividing the bulk density obtained by the Archimedes method based on JIS Z 2501: 2000 by the average true density (total mass of raw material powder / total volume of raw material powder (theoretical value)). Calculated. The raw material powder referred to here refers to the entire raw material such as a matrix, phosphor particles, and a heat conductive filler. The density is increased by adjusting the particle size of the raw material powder, the mixing treatment step, the sintering step, and the like.

When measuring the fluorescent particles and boron nitride in the fluorescent particle dispersed glass, the measurement can be performed as follows, for example, by using an image analysis method or the like based on ISO13383-1: 2012. That is, the test piece is broken and the surface thereof is observed with a scanning electron microscope to obtain a microstructure photograph. The portion of the obtained microstructure photograph corresponding to boron nitride is clarified and the shape is read. The particle diameter is obtained by measuring the longest distance (maximum ferret diameter) at this time. This particle size measurement is repeated, and the obtained values are averaged to obtain an average particle size.

According to the manufacturing method of the present embodiment, by using glass as a matrix, it is possible to bake at a lower temperature as compared with the case where Sialon is used as a matrix. Phosphate-based glass is preferable in that it can be fired at a lower temperature. When phosphate-based glass is used, it can be fired at 600 ° C. or lower, and can be fired at 500 ° C. or lower.

According to the phosphor particle-dispersed glass of the present embodiment, by using boron nitride having excellent corrosion resistance as a heat conductive filler, it is possible to provide a fluorescent particle-dispersed glass having both fluorescence and heat conductivity. Further, it is possible to provide a fluorescent particle dispersion glass having excellent heat resistance, processability and mechanical strength. Further, it is possible to provide a fluorescent particle-dispersed glass having excellent translucency by reducing pores by densifying the fluorescent particle-dispersed glass. Moreover, high thermal conductivity can be realized by containing boron nitride. Further, depending on the type of glass, phosphor particle-dispersed glass can be obtained by, for example, a sintering process at about 400 to 550 ° C., so that various phosphor particles can be used. As a result, conventional problems such as deterioration and alteration of phosphor particles due to high-temperature firing and unwilling reaction with the matrix portion can be fundamentally solved, and material design with a higher degree of freedom becomes possible. As a result, it is possible to provide high-quality phosphor particle-dispersed glass. Then, it is possible to provide a phosphor particle-dispersed glass having both high thermal conductivity and fluorescence. The phosphor particle dispersion glass of the present embodiment can be expected to be applied not only to high-power LEDs and the like but also to various members requiring heat dissipation.

[Light emitting device]
The light emitting device of the present embodiment is a semiconductor light emitting device that emits the first light, and a phosphor of the present embodiment that is installed on the emission light side of the semiconductor light emitting element and the first light becomes excitation light and emits the second light. A particle dispersion glass is provided. In the light emitting device, at least one or a plurality of semiconductor light emitting elements and phosphor particle-dispersed glass are independently contained.

FIG. 1 shows a schematic diagram of a white LED which is an example of the light emitting device according to the present embodiment. In the white LED 10, a blue LED 2 is provided as a primary light source on the substrate 1, and a phosphor particle dispersion glass 6 is installed in at least a part of the emission light path of the blue LED 2. The phosphor particle dispersion glass 6 may be formed in an arbitrary shape according to the shape of the blue LED 2. A part of the emitted light of the blue LED 2 excites the phosphor particles 4, for example, the yellow phosphor particles dispersed in the matrix 3 of the phosphor particle dispersion glass 6, and emits yellow light. Further, among the blue LEDs 2, the light that does not contribute to the excitation of the phosphor particles in the phosphor particle-dispersed glass passes through the phosphor particle-dispersed glass 6 and is emitted from the white LED 10 as blue light. A plurality of emitted lights are mixed to produce white light from the white LED 10.

Further, since the heat conductive filler 5 is dispersed in the phosphor particle dispersed glass 6, the heat conductivity is high. Therefore, the heat generated by the blue LED 2 and the heat generated by the phosphor particles 4 can be effectively dissipated.

The example of FIG. 1 is an example, in which a red LED and / or a green LED is used in place of or in combination with a blue LED, and a phosphor particle-dispersed glass is used to improve the color tint quality of white light. May be good. Further, the yellow phosphor particles are an example, and red fluorescent particles and / and green fluorescent particles can be used in place of or in combination with the yellow fluorescent particles. Of course, phosphor particles of other colors may be used. Further, it goes without saying that a semiconductor light emitting element such as a laser diode may be used instead of the LED.

In the case of the white LED 10, the amount of light that the blue light of the blue LED 2 passes through the phosphor particle dispersion glass 6 and the phosphor particles of the phosphor particle dispersion glass 6 absorb the blue light and light of another wavelength (green light, In order to optimize the amount of light emitted (red light, etc.), the thickness of the phosphor particle-dispersed glass 6 and the concentration of the phosphor particles in the phosphor particle-dispersed glass 6 are appropriately designed. The excitation light from the blue LED is, for example, light having a wavelength of 300 nm to 500 nm (light in the ultraviolet region to light in the blue region).

As shown in FIG. 2, a phosphor particle-dispersed glass 20 composed of a first phosphor particle-dispersed glass 21 and a second phosphor particle-dispersed glass 22 is used instead of the phosphor particle-dispersed glass 6 of the white LED 10 of FIG. White LED 10a may be used. The first phosphor particle-dispersed glass 21 contains the first phosphor particles 12 that absorb the first light from the blue LED 2 and emit light, and the thermally conductive filler 15 in the first matrix 11. On the other hand, the second phosphor particle dispersion glass 22 absorbs the light emitted from the first phosphor particle dispersion glass 21 in the second matrix 13 and further emits long wavelength light, and the second phosphor particles 14 and The heat conductive filler 16 is contained. By using the phosphor particle dispersion glass 20 in which the first phosphor particle dispersion glass 21 and the second phosphor particle dispersion glass 22 are bonded, a part of the emitted light of the phosphor particle dispersion glass 20 is a second excitation light. As a result, it is possible to emit light having a longer wavelength. With such a configuration, it is also possible to adjust the tint of white.

<< Example >>
Hereinafter, the present invention will be described in more detail with reference to Examples. However, the present invention is not limited to the following examples.

(Example 1)
As a raw material powder for glass, a phosphate-based low melting point glass frit (Nippon Amber Glazed Co., Ltd., FRA-119, softening point> 380 ° C., average particle size: 40 μm) was used. Further, 5 wt% Eu-activated Ca-α Sialon (manufactured by Sialon Co., Ltd.) (hereinafter, also referred to as particle 1) as a phosphor particle is used, and h-BN (HGP, Co., Ltd.) which is boron nitride as a heat conductive filler is used. Made by Denka, average particle size: 5 μm) was used.
First, h-BN was added to the glass raw material powder so that the h-BN content was 10% by mass when the total of the glass raw material powder and h-BN was 100% by mass. Next, 5% by mass of the phosphor was added externally to 100% by mass of the total of the raw material powder of glass and h-BN.
These mixtures were placed in a bar bottle and mixed with a shaker mixer (manufactured by Simmal Enterprises Co., Ltd., T2F) for 10 minutes. After that, the phosphor is placed in a carbon mold and vacuum-baked at 500 ° C. using a multipurpose high-temperature sintering furnace (manufactured by Fuji Denpa Kogyo Co., Ltd., Hi-Multi 5000) and hot-pressed at a pressure of 10 MPa for 10 minutes. Particle-dispersed glass was obtained. The temperature rise to 500 ° C. during vacuum firing was performed under vacuum (6.6 × 10 ⁻² Pa or less) under the condition of 5 ° C./min. Further, the pressurization was performed at the timing of holding the temperature at 500 ° C.

(Example 2)
Fluorescent particle dispersed glass by the same raw material / manufacturing method as in Example 1 except that the h-BN content was changed to 20% by mass when the total of the glass raw material powder and h-BN was 100% by mass. Got

(Example 3)
Fluorescent particle dispersed glass by the same raw material / manufacturing method as in Example 1 except that the h-BN content was changed to 30% by mass when the total of the glass raw material powder and h-BN was 100% by mass. Got

(Example 4)
The same as in Example 1 except that 5 wt% Eu-activated β-sialon (manufactured by Sialon Co., Ltd.) (hereinafter, also referred to as particle 2) was used as the fluorescent particle instead of the fluorescent particle of Example 1. Fluorescent particle-dispersed glass was obtained by the raw material and manufacturing method.

(Example 5)
The same as in Example 1 except that 5 wt% Eu-activated CaAlSiN ₃ (manufactured by Sialon Co., Ltd.) (hereinafter, also referred to as particle 3) was used as the fluorescent particle instead of the fluorescent particle of Example 1. Fluorescent particle-dispersed glass was obtained by the raw material and manufacturing method.

(Example 6)
As the heat conductive filler, h-BN particles having different particle diameters (SGP, manufactured by Denka Co., Ltd., 18 μm) were changed to be added in an amount of 10% by mass instead of the heat conductive filler of Example 1, except that A phosphor particle-dispersed glass was obtained by the same production method as in Example 1.

(Comparative Example 1)
Fluorescent particle-dispersed glass was obtained by the same raw material and manufacturing method as in Example 1 except that no heat conductive filler was added.
(Comparative Example 2)
As the heat conductive filler, the same raw materials and production as in Example 1 except that 10% by mass of AlN (grade F, manufactured by Tokuyama Co., Ltd., 0.6 μm) was added instead of the heat conductive filler of Example 1. Fluorescent particle dispersed glass was obtained by the method.
(Comparative Example 3)
Same as Example 1 except that 10% by mass of Si ₃ N ₄ (SN-E10, manufactured by Ube Kosan Co., Ltd., 0.2 μm) was added as the heat conductive filler in place of the heat conductive filler of Example 1. A phosphor-dispersed glass was obtained by the raw material and manufacturing method of.

(Density measurement)
The density was calculated by dividing the bulk density obtained by the Archimedes method based on JIS Z 2501: 2000 by the average true density (total mass of raw material powder / total volume of raw material powder (theoretical value)). The raw material powder referred to here refers to the entire raw material such as the matrix, the phosphor particles, and the heat conductive filler as described above.

(Measurement of emission excitation spectrum)
The fluorescent particle dispersion glass of each Example and Comparative Example was processed into about 7 mm × 7 mm × 1 mm. Then, the emission / excitation spectrum was measured using a fluorescence spectrophotometer (Jasco, FP8500). The emission spectrum was measured in the range of 500 to 750 nm using an excitation wavelength of 450 nm. The excitation spectrum uses an emission wavelength of 582 nm for Ca-α-sialon (yellow) of particle 1, 534 nm for Eu-activated β-sialon (green) of particle 2, and 650 nm for Eu-activated CaAlSiN ₃ (red) of particle 3. It was measured in the range of 250 to 500 nm.

(Measurement of thermal conductivity)
The fluorescent particle dispersion glass of each Example and Comparative Example 1 was processed to 20 × 20 × 1 mm. Then, using LFA467 manufactured by Netch Japan Co., Ltd., the phosphor particle-dispersed glass was measured by the xenon flash method In-plane_Slit method (Slit width 2.5 mm). Then, the value of thermal diffusivity was obtained by Baba model analysis. The thermal conductivity was calculated by multiplying this value by the density and heat capacity (0.8 J / (g · K)) obtained by the above-mentioned measuring method of the fluorescent particle dispersion glass of each Example and Comparative Example.

FIG. 3 shows an SEM image of the phosphor particle-dispersed glass of Example 1. As shown in the figure, it was confirmed that the fluorescent particles and the thermally conductive filler were dispersed in the glass.

FIG. 4 shows the XRD profiles of the phosphor particle-dispersed glasses of Example 1, Comparative Examples 2 and 3. When boron nitride was used as the heat conductive filler, boron nitride remained even after firing, but when silicon nitride and aluminum nitride were added, these peaks did not appear and almost disappeared. In addition, the density remained low due to the release of nitrogen during the reaction. As shown in these results, it was confirmed that by using boron nitride as a thermally conductive filler, a phosphor particle-dispersed glass having excellent thermal conductivity can be obtained.

FIG. 5 shows the emission / excitation spectrum of the phosphor particle-dispersed glass of Example 1. The solid line in the figure is the spectrum of the phosphor particles of the raw material, and the dotted line is the spectrum of the phosphor particle-dispersed glass of Example 1. As shown in the figure, it was confirmed that even if the phosphor particles were dispersed in the phosphor particle-dispersed glass, which is a glass composite containing a heat conductive filler, the same emission / excitation spectrum as the raw material could be obtained.

Table 1 shows the density and thermal conductivity of the fluorophore particle-dispersed glass of Examples 1 to 5 and Comparative Example 1.

As shown in Table 1, the thermal conductivity of Comparative Example 1 containing no thermally conductive filler is 0.5 W / (m · K), whereas the phosphors of Examples 1 to 6 containing boron nitride It was confirmed that the thermal conductivity of the particle-dispersed glass can be significantly increased.

This application claims priority based on Japanese application Japanese Patent Application No. 2019-143318 filed on August 2, 2019, and incorporates all of its disclosures herein.

The phosphor particle-dispersed glass according to the present embodiment can be used as a member of a light emitting device such as a white LED or a high-power LED, and also has high thermal conductivity and fluorescence. Therefore, a fluorescent display tube (VFD), PDP, etc. It can be applied and developed for various purposes in combination with members such as the display of the above. It can also be applied to applications other than phosphor particle-dispersed glass for wavelength conversion, such as stress-stimulated luminescent elements, electron beam-irradiated luminescent elements, and thermoluminescence. It can also be applied to glass that requires heat dissipation to convert ultraviolet light into visible light. Further, a light source capable of emitting the first light having at least the first wavelength spectrum and a phosphor particle-dispersed glass that absorbs the first light at least partially and emits the second light having the second wavelength spectrum. It can be used for all light emitting systems including and.

1 board 2 blue LED
3 Matrix 4 Fluorescent particles 5 Thermally conductive filler 6 Fluorescent particle dispersed glass 10 White LED
11 First Matrix 12 First Fluorescent Particle 13 Second Matrix 14 Second Fluorescent Particle 21 First Fluorescent Particle Distributed Glass 22 Second Fluorescent Particle Distributed Glass

Claims

Using glass as a matrix
At least the fluorescent particles and the thermally conductive filler are dispersed in the matrix.
Fluorescent particle-dispersed glass in which the thermally conductive filler contains boron nitride.
The phosphor particle-dispersed glass according to claim 1, wherein the thermal conductivity is at least 2 W / (m · K) or more.
The phosphor particles according to claim 1 or 2, wherein the average particle diameter of the boron nitride in the matrix determined from the maximum ferret diameter in the ISO 133831: 2012 image analysis method is 0.5 to 200 μm. Distributed glass.
The phosphor particle-dispersed glass according to any one of claims 1 to 3, wherein the boron nitride content is 5% by mass or more.
The phosphor particle-dispersed glass according to any one of claims 1 to 4, wherein the phosphor particles are nitride phosphor particles.
The phosphor particle-dispersed glass according to any one of claims 1 to 5, wherein the glass is a phosphate-based glass.
A semiconductor light emitting device that emits the first light,
The light emitting device provided with the phosphor particle-dispersed glass according to any one of claims 1 to 6, which is installed on the emission light side of the semiconductor light emitting element, and the first light becomes excitation light to emit second light.