JP2014075452A - Glass ceramic body, substrate for mounting light-emitting element, and light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glass ceramic body arranged so that the discoloration owing to a remaining organic component is suppressed, and increased in reflectance.SOLUTION: A glass ceramic body is arranged by baking a green sheet comprising: a glass ceramic composition including glass particles and ceramic particles primarily including planular boehmite particles. In the green sheet, the planular boehmite particles account for 10-45 vol.% to the total content of the glass and ceramic particles.

Description

  The present invention relates to a glass ceramic body, a light emitting element mounting substrate, and a light emitting device.

  2. Description of the Related Art In recent years, light emitting devices using LED elements have been developed as backlights for mobile phones and large liquid crystal TVs as light emitting diode (LED) elements become brighter and whiter. In such a light-emitting device, as a substrate for mounting a light-emitting element such as an LED element, the thermal conductivity is good and heat generated from the light-emitting element is quickly dissipated, and the reflectance for visible light is high, and What is easy to manufacture is desired.

  In response to such a demand, the use of a glass ceramic substrate as a substrate for mounting a light emitting element has been studied. A glass ceramic substrate has a structure in which ceramic particles such as alumina particles are dispersed in a glass matrix, has a large refractive index difference between glass and ceramics, and has many interfaces between them, so it is higher than a ceramic substrate. Reflectance is obtained.

  Such a glass ceramic substrate is obtained by firing a green sheet made of organic components such as glass powder, ceramic powder, and a binder resin. And in the pre-firing process (degreasing process), organic components such as binder resin are decomposed and removed. If the glass softens and flows before the organic components are decomposed, the organic components are sufficiently decomposed and removed. Not done, undecomposed organic components are incorporated into the glass matrix. As a result, there has been a problem that the glass ceramic substrate turns brown due to the remaining organic component, that is, a so-called binder removal failure occurs, and the reflectance decreases.

  By the way, in a glass ceramic substrate, by using a plate-like high aspect ratio and high specific surface area alumina powder, it has been proposed to suppress shrinkage in the XY direction during firing and to improve in-plane dimensional accuracy accompanying shrinkage. (For example, see Patent Document 1 and Patent Document 2).

  However, when using an alumina powder having a high specific surface area, it is necessary to use a glass having a softening temperature lower than that of a glass used for a normal glass ceramic substrate in order to improve the sinterability. When such a glass having a low softening temperature is used, there has been a problem that discoloration (defective binder removal) of the glass ceramic substrate tends to appear.

JP 2012-31040 A WO2011 / 0906126

The present invention has been made in order to solve the above-described problems, and the discoloration (defective binder removal) is prevented and the reflectance is increased by sufficiently decomposing and removing organic components during firing. The object is to provide a glass ceramic body.
It is another object of the present invention to provide a light emitting element mounting substrate and a light emitting device using such a glass ceramic body.

  The glass ceramic body of the present invention comprises a glass ceramic composition comprising glass particles and ceramic particles mainly composed of flat boehmite particles, and the flat boehmite with respect to the total content of the glass particles and the ceramic particles. A green sheet having a particle content ratio of 10 to 40% by volume is fired.

  The substrate for mounting a light emitting element of the present invention is a substrate for mounting a light emitting element, and has the above-described glass ceramic body of the present invention.

  The light emitting device of the present invention includes the above-described light emitting element mounting substrate of the present invention and a light emitting element mounted on the light emitting element mounting substrate.

In the present specification, the term “flat shape” refers to a length (thickness) in the thickness direction that has a wide surface (hereinafter referred to as a flat surface) and is perpendicular to the flat surface rather than the length in the flat surface direction. Is a small shape.
In such flat particles, the maximum diameter in the flat plane (the flat plane is the xy plane, for example, the diameter in the x-axis direction) is referred to as “long axis”, and the thickness perpendicular to the flat plane (for example, in the z-axis direction) Is described as “minor axis”.

  The glass ceramic body of the present invention comprises a glass ceramic composition containing flat boehmite particles at a predetermined ratio, and is obtained by firing a green sheet having a sufficiently high softening / flowing temperature. -Before flowing, the organic components such as the binder resin are sufficiently decomposed and removed. As a result, undecomposed organic components are not taken into the glass matrix and discoloration does not occur. Accordingly, a decrease in reflectance due to such discoloration is prevented, and a high reflectance is obtained.

  Moreover, according to the light emitting element mounting substrate of this invention, a high reflectance can be achieved by applying such a glass ceramic body. Furthermore, according to the light emitting device of the present invention, by using such a high reflectance light emitting element mounting substrate, high light emission luminance can be obtained.

It is a perspective view which shows typically the flat boehmite particle | grains used by embodiment of this invention. It is a graph which shows the method of calculating | requiring shrinkage | contraction start temperature from the TMA curve about a green sheet. It is sectional drawing which shows the light-emitting device of embodiment of this invention.

Hereinafter, embodiments of the glass ceramic body of the present invention will be described.
The glass ceramic body of the embodiment of the present invention is composed of a sintered body of a glass ceramic composition containing glass particles and ceramic particles mainly composed of flat boehmite particles. The glass ceramic body is obtained by firing a green sheet in which the ratio of the content of flat boehmite particles to the total content of glass particles and ceramic particles is 10 to 40% by volume. The phrase “mainly composed of flat boehmite particles” means that flat boehmite particles occupy 50% by volume or more, preferably 55% by volume or more of the entire ceramic particles.

Thus, in the glass ceramic body of the embodiment obtained by firing the green sheet containing the glass ceramic composition, the flat alumina particles formed by firing the flat boehmite particles in the glass matrix, It has a structure in which the flat surfaces are substantially parallel and arranged so that the thickness direction is substantially the same direction. In the present specification, “substantially parallel” and “substantially identical” mean that the images can be viewed as parallel or identical at the visual level when observing an image or an actual object with a microscope or the like.
The state change from the flat boehmite particles to the flat alumina particles is performed before the glass powder melts and flows. Then, since the flat alumina particles are sintered while the surface vicinity is melted in the glass matrix, the size of the flat alumina particles is reduced, but the form of the raw material is substantially maintained. Therefore, a glass ceramic body in which flat alumina particles are dispersed in a glass matrix can be obtained by using flat particles as boehmite particles.

  As will be described later, the green sheet is usually formed by a doctor blade method, and the flat boehmite particles are arranged in parallel to the main surface of the green sheet, so in the glass ceramic body formed by firing the green sheet, The flat alumina particles formed by firing the flat boehmite particles are dispersed in the glass matrix in a state where the flat surfaces are arranged in parallel to the main surface of the glass ceramic body.

Each component constituting the green sheet will be described.
Boehmite, composition formula is alumina hydrate having a boehmite crystal structure represented by AlOOH or _{Al 2 O 3 · H 2 O} . In the present invention, such flat particles of boehmite are used.

  The flat boehmite particles can be produced, for example, by hydrothermal synthesis of aluminum hydroxide. Specifically, a reaction raw material containing aluminum hydroxide and water are filled in an autoclave, heated under pressure, and hydrothermal synthesis is performed with no stirring or low-speed stirring. The reaction product obtained by this hydrothermal synthesis is washed, filtered and dried to obtain boehmite particles.

  A pH adjuster may be added to the reaction raw material as necessary in order to adjust the pH value to 8 or more, preferably 11 or more. Examples of the pH adjusting agent include hydroxides of alkali metals such as sodium and potassium, or hydroxides of alkaline earth metals such as barium, calcium and strontium, and aluminates thereof.

  By adding a pH adjuster to the reaction raw material to make an alkaline reaction system, the solubility of aluminum hydroxide, which is the raw material, can be increased, and the reaction time can be shortened. The size of the boehmite particles produced can be increased.

  The amount of water added as a reaction raw material is preferably 2 to 25 times by mass with respect to aluminum hydroxide. If the mass ratio is less than 2 times, the reaction raw materials cannot be sufficiently reacted. On the other hand, if the mass ratio is more than 25 times, the amount of wasted water is increased and the production cost is increased and the productivity may be lowered. .

  Moreover, it is preferable to add a (meth) acrylic acid ester monomer or polymer to the reaction raw material. This is because it becomes easy to obtain flat boehmite particles. The “(meth) acrylic acid ester system” is a general term for an acrylic acid ester system and a methacrylic acid ester system.

  The temperature in the autoclave during hydrothermal synthesis is preferably 110 to 300 ° C. If it is less than 110 ° C., it is difficult to obtain boehmite particles as a reaction product, and if it exceeds 300 ° C., a large amount of energy is consumed to maintain the temperature, which is disadvantageous in terms of cost.

  The reaction time is preferably 4 to 24 hours, although the heating time varies depending on the respective conditions under stirring or standing. If it is less than 4 hours, the aluminum hydroxide may be unreacted. On the other hand, if the reaction is continued for more than 24 hours, the productivity is lowered, which is disadvantageous in terms of cost.

  FIG. 1 schematically shows the shape of the flat boehmite particles 1. In FIG. 1, the flat surface of the flat boehmite particles 1 is denoted by S, the major axis that is the maximum diameter of the flat surface S is denoted by D, and the minor axis that is perpendicular to the flat surface S is denoted by d. The flat boehmite particles 1 used in the present invention have an average major axis that is an average value of the major axis D of 1 to 10 μm and an average minor axis that is an average value of the minor axis d of 0.05 to 0.5 μm. Some are preferred.

  The major diameter D and minor diameter d of the flat boehmite particles 1 can be calculated by observing 50 particles using a scanning electron microscope (SEM) and averaging the measured values.

The green sheet can contain ceramic particles other than such flat boehmite particles in order to impart functionality to the obtained glass ceramic body. Examples of the ceramic particles other than the flat boehmite particles include alumina, silica, mica, boron nitride, zirconia (ZrO ₂ ) and the like. The shape of the ceramic particles other than the flat boehmite is not particularly limited, but the 50% particle size (D ₅₀ ) of the particles is preferably 1 μm or more and 8 μm or less. _{Incidentally, D 50} is the particle diameter measuring apparatus by laser diffraction scattering method (manufactured by Nikkiso Co., Ltd., trade name: MT3100II) by is obtained.

  For example, when increasing the reflectance of the glass ceramic body, it is preferable to contain ceramic particles having a large difference in refractive index with glass, for example, zirconia particles or boron nitride particles. When increasing the strength of the glass ceramic body, it is preferable to use alumina particles. In order to enhance heat dissipation, it is preferable to use boron nitride.

  The content of the flat boehmite particles as a raw material component of the green sheet is a ratio of 10 to 45% by volume with respect to the total content of the ceramic particles including the flat boehmite particles and the content of the glass particles. And A preferable content ratio of the flat boehmite particles is 20 to 40% by volume.

  Since the content of the flat boehmite particles is 10% by volume or more with respect to the total content of the glass particles and the ceramic particles, the shrinkage start temperature of the green sheet can be 800 ° C. or higher. Before softening and flowing, organic components such as binder resin contained in the green sheet can be sufficiently decomposed and removed. As a result, a glass ceramic body having a high reflectance can be obtained without causing a so-called debinder failure in which an undecomposed organic component is incorporated into the glass matrix and turns brown.

  In addition, by controlling the content of flat boehmite particles to 45% by volume or less, it is possible to suppress a decrease in sinterability of the green sheet due to a decrease in the content of glass particles, and densely sintered glass ceramics without voids. You can get a body.

The shrinkage start temperature of the green sheet can be determined from a heat shrinkage curve (hereinafter referred to as TMA curve) obtained by thermomechanical analysis (hereinafter referred to as TMA).
Here, TMA is a method of measuring the deformation of a substance as a function of temperature or time by applying a non-vibrating load such as compression, tension, bending, etc. while changing the temperature of a sample according to a certain program. When deformation such as thermal expansion or softening of the sample occurs in response to the temperature change, the displacement amount accompanying the deformation is measured by the displacement detection unit as the positional change amount of the probe. In the embodiment of the present invention, TMA measurement is performed using, for example, TMA-50 manufactured by Shimadzu Corporation, and the temperature is increased at a rate of 10 ° C./min while a 10.0 g load is applied to the sample. Measure the amount of shrinkage.

From the TMA curve drawn by the TMA measurement, the shrinkage start temperature is obtained as shown below. That is, in the TMA curve shown in FIG. 2, the linear portion on the low temperature side is extended to the high temperature side than the probe (detection rod) starts to move (descent), and the moving speed (inclination of the TMA curve) is maximized. The tangent line drawn from the point is extended to the low temperature side. And the temperature of the intersection P of these extension lines is made into shrinkage start temperature. In FIG. 2, an example of TMA curves for the green sheet used in the present invention containing the glass particles and flat boehmite particles, indicated by the solid line, the intersection of the extension of the TMA curve and P ₁ . Further, an example of TMA curves for a green sheet containing the glass particles and alumina particles, indicated by broken lines, the intersection of the extension of the TMA curve and P _2.

  The glass particles contained in the green sheet together with such ceramic particles are preferably those that do not produce crystals in the temperature range during the production of the glass ceramic body, specifically during the firing of the green sheet. That is, a glass matrix that is a sintered body of glass particles is preferably not crystallized. That the glass matrix is not crystallized means that there is no crystal that is derived from the glass as a raw material and precipitated from the glass. Confirmation that the glass matrix is not crystallized can be performed by X-ray diffraction. When the maximum intensity (absolute value) of a peak derived from ceramic particles such as alumina particles in an X-ray diffraction spectrum is 100, a glass-derived peak having an intensity of 10 or more does not appear. Suppose not.

  According to the green sheet containing such glass particles, since crystals do not precipitate on the glass matrix during firing, variations in firing shrinkage can be suppressed. As a result, variations in various properties in the obtained glass ceramic body, for example, reflectance Variations in strength and the like can be suppressed. In addition, since no crystals are precipitated, the change in the thermal expansion coefficient is suppressed, and the occurrence of warpage or the like can be suppressed.

The glass constituting the glass particles that are the raw material of the green sheet is preferably alumina borosilicate glass, more preferably SiO ₂ —B ₂ O ₃ —MO (M: alkaline earth metal) glass.

Specifically, the glass particles are expressed on an oxide basis, and the SiO ₂ is 40 to 65 mol%, the B ₂ O ₃ is 13 to 18 mol%, the Al ₂ O ₃ is 0 to 10 mol%, and the CaO is 15 ~40%, MgO, 0~10% in total of at least one selected from the group consisting of SrO and BaO, 0% containing in total at least one selected from the group consisting of Na ₂ O and _{K 2} O and, in mol% of the oxide equivalent in the glass _particles, the total content of SiO _2, B 2 _{O 3} and _Al 2 _{O 3} is preferable to have a composition which is 57-85%.

Hereinafter, the composition of the glass particles will be described. In the description of the glass composition, “%” represents an oxide-converted mol% unless otherwise specified.
SiO ₂ serves as a glass network former and is an essential component for increasing chemical durability, particularly acid resistance. If the content of SiO ₂ is 40% or more, sufficient acid resistance is ensured. Further, when the content of SiO ₂ is 65% or less, the glass softening point (hereinafter referred to as “Ts”) and the glass transition point (hereinafter referred to as “Tg”) are not excessively increased. Adjusted to an appropriate range. The content of SiO ₂ is preferably 43 to 63%.

B ₂ O ₃ is an essential component that becomes a glass network former. When the content of B ₂ O ₃ is 13% or more, Ts is adjusted to an appropriate range without excessively increasing, and the stability of the glass is sufficiently maintained. On the other hand, if the content of B ₂ O ₃ is 18% or less, a stable glass is obtained and the chemical durability is sufficiently ensured. The content of B ₂ O ₃ is preferably 15 to 17%.

Al ₂ O ₃ serves as a glass network former, and is a component blended to increase the stability and chemical durability of the glass. However, since Al ₂ O ₃ derived from flat boehmite is diffused into the glass matrix in the process of becoming a glass ceramic body, it is not an essential component. When the content of Al ₂ O ₃ exceeds 10%, the sinterability with the flat alumina particles is hindered. The content of Al ₂ O ₃ is preferably 0 to 7%.

Each of the network formers SiO ₂ , B ₂ O _3, and Al ₂ O ₃ is blended in the above proportions, and the total content thereof is 57 to 85%. If the total content is 57% or more, the stability, chemical durability, and strength of the glass are sufficiently secured, and if it is 85% or less, an appropriate range without excessively increasing Ts and Tg. Adjusted to The total content of SiO ₂ , B ₂ O ₃ and Al ₂ O ₃ is preferably 60% or more, and more preferably 62% or more.

  CaO is a necessary component to improve wettability between glass and flat alumina particles and to ensure sinterability of the glass ceramic body. If the content of CaO is 15% or more, the eluted alumina is easily diffused into the glass matrix, and the sinterability of glass and alumina can be sufficiently secured. If the content of CaO is 40% or less, crystallization of glass can be suppressed. The content of CaO is preferably 20 to 35%, more preferably 25 to 35%.

  Alkaline earth metal oxides other than CaO such as MgO, SrO and BaO can also improve the wettability with the flat alumina particles while suppressing the crystallization of the glass. It is also useful for adjusting Ts and Tg. At least one selected from the group consisting of MgO, SrO, and BaO is a component that is optionally added as an alkaline earth metal oxide. By blending these alkaline earth metal oxides with a content of 10% or less, Ts and Tg can be adjusted to an appropriate range without excessively decreasing.

Alkali metal oxides such as K ₂ O and Na ₂ O that lower Tg can be added in the range of 0 to 10 mol%. The alkali metal oxide is preferably added in order to suppress phase separation of the glass. However, when the total content of K ₂ O and Na ₂ O exceeds 10 mol%, chemical durability, particularly acid resistance, may be lowered, and electrical insulation may be lowered. The total content of K ₂ O and Na ₂ O is preferably 1 to 8 mol%, more preferably 1 to 6 mol%.

  In addition, glass is not necessarily limited to what consists only of the said component, Other components can be contained in the range with which various characteristics, such as Tg, are satisfy | filled. When it contains other components, the total content is preferably 10 mol% or less.

  The glass particles are obtained by producing glass having the above-described composition by a melting method and pulverizing it by a dry pulverization method or a wet pulverization method. In the case of the wet pulverization method, it is preferable to use water or ethyl alcohol as a solvent. Examples of the pulverizer include a roll mill, a ball mill, and a jet mill.

The D ₅₀ of the glass particles is preferably from 0.5 μm to 2 μm. When the D ₅₀ of the glass particles is less than 0.5 μm, the glass particles easily aggregate and become difficult to handle, and it is difficult to uniformly disperse them. On the other hand, if the D ₅₀ of the glass particles exceeds 2μm, there is a possibility that increase and insufficient sintering of Ts occurs. The particle diameter may be adjusted by classification as necessary after pulverization, for example.

  The glass ceramic body of the embodiment of the present invention can be obtained by firing a green sheet made of a glass ceramic composition containing such glass particles and ceramic particles mainly composed of the flat boehmite particles. In the production of the green sheet described below, glass particles may be referred to as glass powder and ceramic particles may be referred to as ceramic powder.

  The green sheet is prepared by adding a binder and, if necessary, a plasticizer, a solvent, a leveling agent, a dispersant, etc. to a glass ceramic composition containing at least glass powder and ceramic powder. It is obtained by molding into a shape and drying. As the binder, for example, polyvinyl butyral, acrylic resin or the like can be preferably used. As the plasticizer, for example, dibutyl phthalate, dioctyl phthalate, butyl benzyl phthalate and the like can be used. As the solvent, aromatic or alcoholic organic solvents such as toluene, xylene and butanol can be used. It is preferable to use a mixture of an aromatic solvent and an alcohol solvent. Further, a dispersant or a leveling agent can be used in combination.

  Next, the obtained slurry is applied onto a PET film coated with a release agent using, for example, a doctor blade to form a sheet and then dried, whereby a green sheet can be produced.

  In the green sheet manufactured by such a doctor blade method, the above-described flat boehmite particles are oriented in a direction parallel to the main surface, which is considered to be due to the following reasons. That is, during the application by the doctor blade method, the slurry containing glass powder and ceramic powder passes through the gap formed by the tip of the blade part of the doctor blade device and the surface of the film, so that the flow of the slurry (streamline ) Along the film transport direction. At this time, the ceramic particles dispersed in the slurry also pass through the gap so as to follow the flow of the slurry. Therefore, in the green sheet, the flat boehmite particles are oriented so that the direction of the flat surface is parallel to the surface direction (main surface) of the sheet. When the flat surface has a longitudinal direction such as a rectangle and a short direction, the longitudinal direction, that is, the major axis direction of the flat boehmite particles is substantially the same as the forming direction of the doctor blade method.

  In addition to the doctor blade method, there are a roll molding method, an extrusion molding method, and the like as the green sheet forming method. However, in any method, the raw material is flowed in a certain direction. The flat boehmite particles therein are oriented in the same manner as in the doctor blade method. In the present invention, a doctor blade method is preferred as a method for forming a green sheet because a green sheet in which flat flat boehmite particles are oriented in the same direction parallel to the main surface at a high ratio can be stably obtained.

  In the present invention, the green sheet thus obtained has a higher shrinkage start temperature measured by the TMA than the green sheet containing alumina particles (for example, 780 ° C. or higher), and has a softening / flowing temperature during firing. It is expensive enough. Therefore, when this green sheet is used, it is possible to sufficiently decompose and remove organic components such as binder resin before the glass in the green sheet softens and flows during firing, and there is no defective binder removal. Can be obtained.

  In the green sheet, element connection terminals, external connection terminals, through conductors (connection vias) for interlayer connection, etc., which are unfired wiring patterns, can be formed. The method for forming unfired element connection terminals and external connection terminals is not particularly limited, and can be performed by applying a conductive paste by a screen printing method. Further, the unfired connection via can be formed by forming a hole for via connection (via hole) on the green sheet by a method such as punching (punching) and filling the hole with a conductive paste by screen printing. . As the conductive paste, for example, a paste obtained by adding a vehicle such as ethyl cellulose to a metal powder containing copper, silver, gold, aluminum or the like as a main component and, if necessary, a solvent or the like can be used.

  The green sheets obtained in this way are overlaid while aligning a plurality of sheets as necessary, and are integrated by thermocompression bonding. And after degreasing for decomposing | disassembling and removing binder resin etc., it is baked and a glass ceramic composition is sintered and a glass ceramic body is obtained. Specifically, for example, a glass ceramic substrate for mounting a light emitting element is obtained.

  Generally, in a degreasing process, organic components, such as binder resin, are fully decomposed | disassembled and removed by hold | maintaining at the temperature of 500-600 degreeC for 1 to 10 hours, for example. When the degreasing temperature is less than 500 ° C. or the degreasing time is less than 1 hour, the organic component may not be sufficiently decomposed and removed. However, when a green sheet containing 10% by volume or more of flat boehmite particles is used as a raw material, it is not necessary to maintain the temperature in the temperature range of 500 to 600 ° C., and the rate of temperature increase to the firing peak temperature is 50 ° C. / Even organic components can be sufficiently decomposed and removed. That is, in the present invention, the degreasing process can be omitted, and the firing time can be shortened.

  In a baking process, it hold | maintains for 20 to 60 minutes at the temperature of 850-900 degreeC, for example. In particular, firing is preferably performed at a temperature of 860 to 880 ° C. If the firing temperature is less than 850 ° C. or the firing time is less than 20 minutes, a dense sintered body may not be obtained. If the firing temperature is about 900 ° C. and the firing time is about 60 minutes, a sufficiently dense product can be obtained, and if this is exceeded, productivity and the like may be reduced.

  The glass ceramic body of the present invention thus obtained is obtained by firing a green sheet made of a glass ceramic composition containing the flat boehmite particles in the above-described predetermined ratio. Therefore, in the degreasing step, an organic component such as a binder resin can be obtained. As a result of sufficient decomposition and removal, a so-called debinder failure in which an undecomposed organic component is incorporated into the glass matrix and turns brown is not caused. Therefore, a decrease in reflectance is prevented and a high reflectance is obtained.

  In the glass ceramic body of the present invention, the reflectance of light having a wavelength of 460 nm when the thickness is 300 μm is preferably 75% or more, and more preferably 80% or more.

  Thus, the firing of the glass ceramic composition (green sheet) containing the flat boehmite particles at a predetermined ratio can greatly improve the binder removal failure because the shrinkage of the green sheet used in the present invention starts. The temperature is higher than 780 ° C., which is higher than that of a normal green sheet using alumina particles as ceramic particles. The shrinkage start temperature of the green sheet increases as described below (1) or ( This is considered to be based on the mechanism of 2).

(1) When a green sheet containing flat boehmite particles that are hydrated alumina is degreased and then fired, the crystal water in the boehmite is desorbed at around 300 to 400 ° C. And since the water produced on this high temperature condition adheres to the surface of ceramic particles or glass particles, the start of sintering of the glass ceramic composition is delayed. Therefore, the shrinkage start temperature of the green sheet increases.
(2) The crystal phase of boehmite particles is transformed in the degreasing / firing process of the green sheet. In this phase transformation process, the start of sintering of the glass-ceramic composition is delayed as a result of suppressing the wettability between the glass and the ceramic particles (boehmite particles). Therefore, the shrinkage start temperature of the green sheet increases.

  The glass ceramic body according to the embodiment of the present invention and the glass ceramic substrate for mounting a light emitting element (hereinafter, referred to as a light emitting element mounting substrate) as an example of the glass ceramic body have been described. However, the configuration can be appropriately changed as long as it is not contrary to the above. Next, the light emitting device of the present invention will be described.

  As shown in FIG. 3, the light emitting device 10 of the present invention is configured by mounting a light emitting element 12 such as a light emitting diode (LED) chip on a mounting portion of a light emitting element mounting substrate 11. The light emitting element 12 is fixed to the mounting portion with an adhesive 13, and an electrode (not shown) of the light emitting element 12 is connected to an element connection terminal 14 formed on the light emitting element mounting substrate 11 with a bonding wire. 15 is connected. A sealing layer 16 made of a resin or the like is provided so as to cover the light emitting element 12 and the bonding wire 15. Reference numeral 17 denotes an external connection terminal provided on the back surface of the light emitting element mounting substrate 11, and 18 denotes a connection via for electrically connecting the external connection terminal 17 and the element connection terminal 14. In addition, you may seal using the cover body which consists of translucent materials, such as glass, without using the sealing layer 16 which consists of resin etc., and you may use the sealing layer 16 and a cover body together. . Further, the phosphor may be contained in the sealing layer 16 so that the wavelength of light emitted from the light emitting element 12 may be converted.

  According to the light emitting device 10 of the present invention, by using the light emitting element mounting substrate 11 that has no discoloration due to defective binder removal and has a high reflectance, light emitted from the light emitting element 12 is reflected upward with a high reflectance. Luminous light emission can be obtained. Such a light emitting device 10 of the present invention can be suitably used as a backlight for a mobile phone, a large liquid crystal display, etc., illumination for automobiles or decoration, and other light sources.

  Hereinafter, the glass ceramic body of the present invention will be described based on examples.

Examples 1 and 2 and Comparative Examples 1 and 2
In terms of oxide, SiO ₂ is 46.6 mol%, B ₂ O ₃ is 15.1 mol%, Al ₂ O ₃ is 2.8 mol%, CaO is 32.6 mol%, and Na ₂ O is The raw materials were blended and mixed so as to be 2.9 mol%. The raw material mixture was put in a platinum crucible and melted at 1200 to 1500 ° C. for 60 minutes, and then the melt was poured out and cooled. The cooled product was pulverized for 10 to 60 hours using water as a solvent by an alumina ball mill, and classified to obtain glass particles G (D ₅₀ 1.5 μm).

  Separately, flat boehmite particles were produced from aluminum hydroxide by hydrothermal synthesis. First, aluminum hydroxide, sodium hydroxide or calcium carbonate as a pH adjusting agent, and water were charged into an autoclave. Here, the pH was adjusted to 8 or more, and the mixing ratio of water was 5 times or more of the amount of aluminum hydroxide in mass ratio. And it was made to react for 2 to 10 hours under 150-200 degreeC and natural pressurization. Thereafter, it was washed with water and filtered to obtain flat boehmite particles. When the average major axis and the average minor axis (thickness) of the flat boehmite particles were measured, the average major axis was 2.0 μm and the average minor axis was 0.05 μm. The average major axis and the minor axis were obtained by observing 50 particles by SEM observation, measuring the major axis and the minor axis using an image analyzer, and obtaining the average value.

The flat boehmite particles thus obtained are calcined at 450 to 900 ° C., and flat alumina particles having a γ-alumina structure having an average major axis of 3 μm and an average minor axis of 0.1 μm (hereinafter referred to as γ-alumina). Indicated as particles). Further, the flat boehmite particles are fired at 1200 to 1500 ° C., and have flat α-alumina structure (hereinafter referred to as α-alumina particles) having an α-alumina structure having an average major axis of 2.5 μm and an average minor axis of 0.1 μm. )
Note that the average major axis and the average minor axis were measured in the same manner as in the flat boehmite particles.

Next, glass particles G and ceramic particles were blended and mixed in the proportions (volume%) shown in Table 1. As the ceramic particles, the flat boehmite particles were used in Examples 1 and 2, the γ-alumina particles were used in Comparative Example 1, and the α-alumina particles were used in Comparative Example 2. In Example 2, together with flat boehmite particles, zirconia (ZrO ₂ ) particles having a D ₅₀ of 0.5 μm and a specific surface area of 8.0 m ² / g (trade name: HST, manufactured by Daiichi Rare Element Chemical Co., Ltd.) -3F) was blended at the ratio shown in Table 1.

  Next, 50 g of these mixed powders, 15 g of an organic solvent (mixed with toluene, xylene, 2-propanol and 2-butanol at a mass ratio of 4: 2: 2: 1), a plasticizer (di-2-ethylhexyl phthalate) ) 2.5 g, 5 g of polyvinyl butyral as a binder (trade name: PVK # 3000K, manufactured by Denka) and 0.5 g of a dispersant (trade name: BYK180, manufactured by Big Chemie) are mixed and mixed to form a slurry. did. This slurry was applied onto a PET film by a doctor blade method, dried and then cut to produce a green sheet having a thickness of 0.2 mm and a 40 mm square (40 mm length × 40 mm width).

  Next, TMA measurement was performed on the green sheet thus obtained. The measurement was performed using TMA-50 manufactured by Shimadzu Corporation under the conditions of a load of 10.0 g and a heating rate of 10 ° C./min. And the shrinkage start temperature was calculated | required by the above-mentioned method from the obtained TMA curve. The results are shown in Table 1.

  Next, the obtained six green sheets were superposed and integrated by applying a pressure of 10 MPa at 80 ° C., and the thickness after firing became 300 μm. Thereafter, the binder resin was decomposed and removed by holding at 550 ° C. for 5 hours, and then baking was carried out by holding at 870 ° C. for 1 hour. Thus, a reflectance measurement substrate having a thickness of 300 μm was obtained. The surface reflectance of this substrate was measured. The reflectance was measured using a spectroscope USB2000 from Ocean Optics and a small integrating sphere ISP-RF as light reflectance (unit:%) at 460 nm. The results are shown in Table 1. In addition, about this board | substrate, when the crystallinity degree of glass was investigated by X-ray diffraction, it was confirmed that all are not crystallizing.

  As is clear from Table 1, the green sheets of Example 1 and Example 2 containing flat boehmite particles in a proportion of 10 to 45% by volume with respect to the total amount of glass particles and ceramic particles start shrinkage by TMA. The glass ceramic substrates of Example 1 and Example 2 obtained by firing these green sheets at a high temperature of 800 ° C. or higher were able to obtain a high reflectance of 75% or higher.

  On the other hand, as the ceramic particles, the green sheet of Comparative Example 1 containing γ-alumina particles instead of flat boehmite particles and the green sheet of Comparative Example 2 containing α-alumina particles have a shrinkage start temperature by TMA of 780. The glass ceramic substrates of Comparative Example 1 and Comparative Example 2 obtained by firing these green sheets at a temperature lower than 0 ° C. are significantly lower in reflectance than the glass ceramic substrates of Example 1 and Example 2. It was.

DESCRIPTION OF SYMBOLS 1 ... Flat boehmite particle | grains, 10 ... Light-emitting device, 11 ... Light emitting element mounting substrate, 12 ... Light emitting element, 14 ... Element connection terminal, 15 ... Bonding wire, 16 ... Sealing layer, 17 ... External connection terminal.

Claims (9)

  A glass ceramic composition comprising glass particles and ceramic particles mainly composed of flat boehmite particles, wherein the ratio of the content of the flat boehmite particles to the total content of the glass particles and the ceramic particles is 10 A glass ceramic body obtained by firing a green sheet of ˜45% by volume.   The glass ceramic body according to claim 1, wherein the glass ceramic body does not have crystals derived from glass constituting the glass particles.   The glass ceramic body according to claim 1, wherein the flat boehmite particles have an average major axis of 1 to 10 μm and an average thickness of 0.05 to 0.5 μm.   The glass ceramic body according to any one of claims 1 to 3, wherein the green sheet has a shrinkage start temperature of 800 ° C or higher by thermomechanical analysis (TMA).   The glass ceramic body according to any one of claims 1 to 4, wherein the reflectance of light having a wavelength of 460 nm is 75% or more at a thickness of 300 µm. The glass particles, glass-ceramic body according to any one of claims 1 to 5 consisting of _SiO 2 _-B 2 _{O 3} based glass containing 15 to 40 mol% of CaO in oxide reference display.   The glass ceramic body according to any one of claims 1 to 6, wherein the ceramic particles contain zirconia particles. A substrate for mounting a light emitting element,
A substrate for mounting a light-emitting element, comprising the glass ceramic body according to claim 1. The light emitting element mounting substrate according to claim 8,
And a light emitting device mounted on the light emitting device mounting substrate.

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