JP5623587B2 - LIGHT REFLECTOR, LIGHT EMITTING DEVICE MOUNTING WIRING BOARD, AND LIGHT EMITTING DEVICE - Google Patents

Description

  The present invention relates to a light reflector suitably used in a light reflecting portion of a light emitting element for mounting a light emitting element such as a light emitting diode, a light emitting element mounting wiring board using the same, and a light emitting device.

  Conventionally, light emitting devices using LEDs have been used for various applications because of their extremely high luminous efficiency and the small amount of heat generated with light emission compared to incandescent bulbs. However, since it emits less light than incandescent bulbs and fluorescent lamps, it is not used for illumination but as a light source for display, and the energization amount is as small as about 30 mA.

  However, in recent years, with the increase in brightness and whiteness of light-emitting devices using light-emitting elements, light-emitting devices have been frequently used for backlights of mobile phones and large liquid crystal TVs. Among them, a light reflector that uses crystalline glass has been proposed (see, for example, Patent Document 1).

JP 2000-16833 A

  However, although the crystalline glass reflector described in Patent Document 1 is described as being used as an insulating reflective film of a plasma display panel, the reflectance in the visible light region is as low as 15 to 20%. Even though the panel can be used, there is a problem that the efficiency is low in a device requiring high luminance such as a light emitting device for a portable terminal or a light emitting device for illumination. In particular, a light emitting device for a device using a battery such as a mobile phone has a problem that the use time is shortened if the efficiency is low. In addition, the light emitting device for illumination has a problem that the amount of light becomes insufficient.

  Accordingly, an object of the present invention is to provide a light reflector having a high reflectance in the visible light region, a light emitting element mounting wiring board using the same, and a light emitting device.

Light reflector of the present invention is made of a glass ceramic containing a glass and ceramic particles, along with containing an average particle diameter 1.3μm or more of the alumina particles in a cross section of the glass ceramic particle size of the ceramic particles The occupied area of the particle group of 0.3 to 1.0 μm is 10 to 70% of the cross section.

  The ceramic particles are at least one selected from the group consisting of alumina, zirconia, serdian, slusonite, anorthite, diopsite, forsterite, enstatite, garnite, spinel, willemite, cordierite, mullite, quartz, and solid solutions thereof. It preferably consists of seeds.

  Of the occupied area of the particle group, the occupied area of particles having an aspect ratio of 3 or more is preferably 20% or more.

It is preferable that the glass ceramic does not substantially contain a transition metal element.

  The light-emitting element mounting wiring board of the present invention is a light-emitting element mounting wiring board in which a wiring layer and a light-emitting element mounting part for mounting a light-emitting element are provided on a main surface of an insulating substrate. It consists of the said light reflector.

  The light emitting device of the present invention is characterized in that a light emitting element is mounted on the light emitting element mounting portion of the light emitting element mounting wiring board.

  The light reflector of the present invention is made of glass ceramics containing glass and ceramic particles, and in the cross section of the glass ceramics, the area occupied by the particle group in which the particle diameter of the ceramic particles is 0.3 to 1.0 μm. By being 10 to 70% of the cross section, visible light having a wavelength of 400 to 700 nm is scattered, and the reflectance can be increased in the wavelength region of visible light. In other words, since glass and ceramic particles have different refractive indexes, light scattering occurs at the interface between them, but at that time, the particle size of the ceramic particles is close to the wavelength of visible light, so that the efficiency of scattering is improved and visible light is scattered. The reflectance increases in the wavelength region.

It is sectional drawing which shows an example of the fine structure of the glass ceramics which are the light reflection bodies of this invention. It is sectional drawing which shows an example of the fine structure of the glass ceramics which are the light reflection bodies of this invention. It is sectional drawing which shows the wiring board for light emitting element mounting of this invention. It is sectional drawing which shows the light-emitting device of this invention.

  The present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic cross-sectional view of an embodiment of the light reflector of the present invention.

  The light reflector of the present invention is made of glass ceramics 1, and glass ceramics 1 contains, for example, glass 3 and ceramic particles such as ceramic particles 5 and ceramic particles 7.

  The light reflector of the present invention is made of glass ceramics containing glass and ceramic particles, and in the cross section of the glass ceramics, the area occupied by the particle group in which the particle diameter of the ceramic particles is 0.3 to 1.0 μm. It is important that it is 10 to 70% of the cross section.

  By adopting such a configuration of the light reflector of the present invention, high reflectance can be obtained because light is efficiently scattered at the interface between glass and ceramic particles having different refractive indexes. Visible light is reflected particularly efficiently by setting the particle diameter in the cross section to a size close to 400 nm (0.4 μm) to 700 nm (0.7 μm), which is a visible light wavelength region, of 0.3 to 1.0 μm. Therefore, it becomes possible to show a high reflectance in the wavelength region of visible light.

In order to increase the reflectance of visible light, it is more preferable that the occupied area of the particle group of ceramic particles having a particle diameter of 0.3 to 0.8 μm in the cross section is 15 to 65% of the cross section. The area occupied by the particle group of ceramic particles having a particle diameter of 0.4 to 0.7 μm is optimally 20 to 60% of the cross section.

  The particle diameter in the cross section of the present invention is a value calculated from an image taken with a scanning microscope (SEM) after mirror-polishing the cross section of the glass ceramic. This is the diameter of the particle when the cross-sectional shape is approximated by a circle, and for particles having an aspect ratio of 3 or more, it is the short diameter of the particle. In the case of anisotropic particles with a large aspect ratio, if the circular approximation is performed, the difference between the actual particle size and the diameter of the particle in the circular approximation becomes large. The particle diameter in the cross section was taken.

  Here, the aspect ratio is the longest / shortest diameter when the longest of the line segments that bisect the cross-sectional area of the particle is the major axis of the particle in the cross section and the shortest is the minor axis of the particle in the cross section. It is a diameter. Here, the circular approximation means that the cross-sectional area of a particle is measured, and the diameter of a circle having the same area as the cross-sectional area is taken as the particle diameter in the cross-section. In addition, the particle diameter in the cross section of the present invention for a true spherical particle having a particle diameter of 1.27 μm is about 1.0 μm on average in the calculation.

The cross section where the measurement is performed is a cross section substantially parallel to the light reflecting surface of the light reflector, and the measurement may be performed over a range of 100 μm ² . In addition, when the surface which reflects the light of a light reflector is less than 100 micrometers ² , what is necessary is just to measure the whole cross section substantially parallel to the surface to reflect. For particles that cross the boundary of the measurement range, the aspect ratio and the particle diameter in the cross section are measured for the entire cross section of the particle, including the part that exceeds the measurement range, and the area is the cross section of the particle. What is necessary is just to measure the part within a measurement range. For this purpose, the range to be photographed with a scanning microscope is set to a range wider than the measurement range so that the particle diameter of the particles straddling the boundary of the measurement range can be measured.

  Ceramic particles having a particle diameter of 0.3 to 1.0 μm in cross section may be added as a filler to be mixed with glass at the raw material powder stage when producing glass ceramics. From the viewpoint of manufacturing a light reflector, it is preferable to deposit ceramic particles as a fine crystal phase. Then, since fine powder having an average particle size of about 1.3 μm or less is not used as a filler, the cost of manufacturing the filler increases, the filler aggregates, etc. No cracks occur in the glass ceramics.

  Furthermore, in order to control characteristics other than the reflectance of the light reflector, such as bending strength, dielectric constant, dielectric loss, thermal expansion coefficient, etc., the average particle diameter that is easy to manufacture as a filler is about 1.3 μm or more. When the ceramic particles 7 are used and the ceramic particles 5 which are fine crystal phases are precipitated from the glass during firing, various characteristics can be imparted to the light reflector and the production can be easily performed. This is preferable.

  The ceramic particles of the present invention are selected from the group consisting of alumina, zirconia, serdian, slausonite, anorthite, diopsite, forsterite, enstatite, garnite, spinel, willemite, cordierite, mullite, quartz, and solid solutions thereof. It is preferable that there is at least one. Since these ceramic particles do not have a light absorption band peculiar to the visible light region and are colorless and transparent crystals, the reflectance of the light reflector can be further increased. The ceramic particles are preferably zirconia, garnite, and spinel in that fine crystal particles having a cross-sectional particle size of 0.3 to 1.0 μm are easily obtained.

The ceramic particles 5 shown in FIG. 1 are, for example, garnite precipitated from glass by firing, and the ceramic particles 7 are alumina as a filler. With such a configuration, the ceramic particles having a particle diameter in the cross section of 0.3 to 1.0 μm are mainly garnite, and the ceramic having a particle diameter in the cross section of 0.3 to 1.0 μm. When the ratio of the area occupied by the particles is 10 to 70%, the reflectance of the light reflector made of the glass ceramics 1 is increased. Further, since the ceramic particles 7 are alumina, it is easy to impart characteristics such as high strength and excellent corrosion resistance to the light reflector made of the glass ceramic 1.

  In addition, FIG. 1 illustrates the case where there are two types of ceramic particles, ceramic particles 5 and ceramic particles 7, but the number of ceramic particles may be one or three or more. . Further, the glass 3 may be a mixture of a plurality of glasses instead of a single type. In order to mix a plurality of glasses, in addition to a method of using a plurality of types of glasses as raw materials at the raw material powder stage, a method of phase separation during firing can be selected.

  Further, if the crystallinity of the glass ceramics 1 is 50% or more, particularly 60% or more, the amount of crystal particles in the glass ceramics 1 increases, so that the interface between the glass 3 and the ceramic particles 5 or ceramic particles 7 is increased. It is preferable because it increases and a higher reflectance can be obtained.

  Here, the degree of crystallinity is defined by the sum of the masses of all the crystal phases in the glass ceramics / the mass of the glass ceramics, and represents the ratio of the crystal phases contained in the glass ceramics in a mass ratio. It is. The mass of the crystal phase in the glass ceramic is calculated by Rietveld analysis. Therefore, the crystal phase is measured including all of those added as a raw material powder as a filler, those precipitated from glass during firing, and those generated by the reaction between glass and filler.

Moreover, by not containing a transition metal element substantially, the fall of the reflectance by the absorption band peculiar to a transition metal element can be suppressed. Furthermore, since the reflectance of the absorption band is low, a difference in color tone between incident light and reflected light can be reduced. Thereby, when white light is required for illumination or the like, white reflected light can be stably obtained. For example, Cr ₂ O ₃ is green, Co ₃ O ₄ is blue, CeO ₂ is yellow, Such as TiO ₂ and MnO that are originally white, but have the property of being colored due to valence changes due to changes in the firing atmosphere, reaction / solid solution, etc. There is something that is.

  Here, “not containing substantially” means not intentionally containing, and may contain unavoidable impurities. The content is preferably 1% by mass or less, particularly preferably 0.1% by mass or less.

  In addition, a light-emitting device exhibiting a high reflection efficiency, in particular, has a reflectance of 75% or more, particularly 80% or more, and optimally 85% or more over the entire wavelength range of 400 to 700 nm, which is the wavelength region of visible light. It is preferable to obtain

  In addition, by setting the reflectance to 75% or more in the entire wavelength region of visible light, light that is absorbed or transmitted through the light reflector is reduced, and a light-emitting device with higher luminous efficiency can be obtained. .

  Next, the manufacturing method of the light reflector of this invention is explained in full detail.

First, for example, glass powder and ceramic powder having an average particle diameter of 1 to 5 μm are prepared as raw material powder. At this time, as the glass powder, it is more preferable to use crystallized glass in which a crystal phase is precipitated during firing. Here, crystallized glass is glass in which part or all of the glass is precipitated as crystals upon firing. The above raw material powder is weighed at a desired mixing ratio, an appropriate organic binder, a solvent and the like are added, and then mixed to obtain a slurry.

  The obtained slurry is formed into a desired shape by a desired forming means such as a die press, cold isostatic pressing, injection molding, extrusion molding, doctor blade method, calendar roll method, rolling method, printing, and the like. In particular, a doctor blade method is suitable for producing a green sheet.

  Next, in firing the above molded body, first, the organic binder component blended for molding is removed. And a light reflector can be obtained by baking for 0.2 to 10 hours, especially 0.5 to 5 hours in 700-1000 degreeC oxidizing atmosphere or non-oxidizing atmosphere.

  In particular, when crystallized glass is used as the glass powder, it is effective to control the firing pattern in order to control the precipitation of crystals having a particle diameter of 0.3 to 1.0 μm in the cross section to an appropriate size. It is. That is, the nucleation temperature and crystallization temperature are measured in advance. For example, in order to refine the precipitated crystal phase, a retention pattern is provided near the nucleation temperature during firing to increase the amount of nucleation. On the other hand, when it is desired to grow a precipitated crystal phase, it is effective to raise the temperature rapidly to near the crystallization temperature to suppress nucleation.

  FIG. 2 is a schematic cross-sectional view of another embodiment of the light reflector of the present invention.

  The light reflector of the present invention is made of glass ceramics 11. The glass ceramics 11 includes, for example, glass 13, ceramic particles 15, ceramic particles 17, and anisotropic ceramic particles 19, and the like. It contains.

  The light reflector of the present invention is made of glass ceramics containing glass and ceramic particles, and in the cross-section of the glass ceramics, the ceramic particles have an area occupied by a particle group having a particle diameter of 0.3 to 1.0 μm. Among them, the area occupied by the ceramic particles having an aspect ratio of 3 or more is preferably 20% or more, and more preferably 30% or more. An aspect ratio of 3 or more, that is, anisotropic ceramic particles 19 such as needle crystals and plate crystals can reflect light in a wide range of wavelengths with one ceramic particle, compared to isotropic particles. Therefore, it is possible to obtain a higher reflectance in the visible light region.

  In order to increase the ratio of ceramic particles having a particle diameter in the cross section of 0.3 to 1.0 μm and an aspect ratio of 3 or more, the ceramic particles should be at least one of alumina and serdian that form anisotropic crystals. Is preferred.

  The ceramic particles 15 shown in FIG. 2 are, for example, garnite precipitated from glass by firing, the ceramic particles 17 are alumina as fillers, and the anisotropic ceramic particles 19 are serdians precipitated from glass by firing. By adopting such a configuration, ceramic particles having a particle diameter in the cross section of 0.3 to 1.0 μm are mainly serdian and garnite, and the particle diameter in the cross section is 0.3 to 1.0 μm. If the ratio of the area occupied by the ceramic particles is 10 to 70%, the reflectance of the light reflector made of the glass ceramic 11 becomes high. In addition, particles having an aspect ratio of 3 or more in the cross section are mainly serdians. If the area occupied by the particles having an aspect ratio of 3 or more in the cross section is 20% or more, the light composed of the glass ceramics 11 is used. It becomes easy to further increase the reflectance of the reflector. In addition, since the ceramic particles 17 are alumina, it is easy to impart characteristics such as high strength and excellent corrosion resistance to the light reflector made of the glass ceramic 11.

  In order to increase the ratio of ceramic particles having a cross-sectional particle size of 0.3 to 1.0 μm and an aspect ratio of 3 or more, the same firing pattern control as described above is performed, particularly for anisotropic ceramic particles. It is effective.

  FIG. 3A is a cross-sectional view of an embodiment of the light emitting element mounting wiring board of the present invention.

  The wiring board 113 for mounting a light emitting element of the present invention connects an insulating base 103 formed by laminating insulating layers 101a to 101c and a light emitting element to be mounted formed on one main surface 103a of the insulating base 103. A connection terminal 105 serving as a terminal, an external electrode terminal 107 formed on the other main surface 103 b of the insulating base 103, and the insulating base 103 are formed to connect the connection terminal 105 and the external electrode terminal 107. And the light reflector 111 formed on the main surface 103 a of the insulating base 103.

  The insulating substrate 103 may be a laminated body as shown in FIG. 3A or a bulk body.

  The light reflector 111 is provided with a light emitting element mounting portion 115 on which a light emitting element is mounted.

  The insulating base 103 is preferably made of an aluminum nitride sintered body having a high thermal conductivity. The insulating layer 101a is made of an aluminum nitride sintered body, and the light reflector 111 is formed on the main surface of the insulating layer 101a. For example, even when an aluminum nitride sintered body having a low light reflectance is used as the insulating layer 101a, the light emitting element mounted on the light emitting element wiring substrate 113 is used. The light emitting element mounting wiring board 113 can efficiently use light.

  That is, the emitted light of the light emitting element mounted on the light emitting element mounting portion 115 is reflected by the light reflector 111 by the light reflector 111 formed on the main surface 103a of the light emitting element mounting wiring substrate 113, and the emitted light is insulated. Absorption to the base 103 or permeation through the insulating base 103 can be suppressed.

  Therefore, not only the light directly emitted from the light emitting element but also the light reflected by the light reflector 111 can be guided in an arbitrary direction, so that it is possible to supply stronger light and to improve the light emission efficiency. It can be much higher.

  That is, according to the light emitting element mounting wiring substrate 113 of the present invention, by providing such a light reflector 111, the insulating base 103 is, for example, black and has a very low reflectance. Alternatively, even when the insulating substrate 103 has high translucency, the reflectance of the light emitting element mounting wiring substrate 113 can be increased.

  Therefore, even when a highly heat-conductive aluminum nitride sintered body, an inexpensive and high-strength alumina sintered body, or an inexpensive resin printed board is used as the insulating base 103, a high reflectance is obtained. The light-emitting element wiring board 113 can be realized by utilizing the characteristics of the insulating base 103.

  By setting the thickness of the light reflector 111 to 25 μm or less, the thermal resistance of the light reflector 11 can be kept low, and it is possible to obtain the light emitting element wiring substrate 13 having excellent heat dissipation from the light emitting element and good light emission efficiency. it can. In particular, the thickness of the surface reflective layer 11 is preferably 20 μm or less, more preferably 15 μm or less.

As the connection terminal 105, the external electrode terminal 107, and the through conductor 109, the insulating base 103
In the case where is an aluminum nitride sintered body or an alumina sintered body, a material mainly composed of at least one of W and Mo can be exemplified. Further, the reflectance can be improved by applying Al or Ag plating to the surface of the connection terminal 105.

  Further, for example, as shown in FIG. 3B, a frame body 216 for housing the light emitting elements to be mounted may be formed on the insulating base 103 on the light emitting element mounting portion 115 side.

  The frame 216 preferably has a function of reflecting light emitted from the light emitting element and guiding the light in a desired direction. The frame 216 has an inner wall surface 216a that receives the emitted light of the light emitting element. It is desirable that the reflectance of the glass is 70% or more. In particular, it is desirably 75% or more, and more preferably 80% or more.

  By forming the frame body 216 from ceramics, the insulating base 103 and the frame body 216 can be fired at the same time, and the process is simplified. Therefore, an inexpensive light-emitting element mounting wiring substrate 213 can be easily manufactured. Can do. In addition, since ceramics are excellent in heat resistance and moisture resistance, the light emitting element mounting wiring substrate 213 has excellent durability even when used for a long period of time or under adverse conditions.

  In addition, by forming the frame body 216 from a metal that is inexpensive and excellent in workability, even the frame body 216 having a complicated shape can be easily manufactured at low cost, and an inexpensive wiring board for a light-emitting element. 213 can be supplied. The metal frame 216 can be suitably formed from, for example, Al, Fe—Ni—Co alloy, or the like. A plating layer (not shown) made of Ni, Au, Ag, or the like may be formed on the surface of the frame 216.

  When the frame body 216 is formed of a metal in this way, a metal layer 217 is formed in advance on the main surface 103a of the insulating base 103 or the main surface 103a of the insulating base 103, and the metal layer 217 and the frame body 216 are formed. For example, it can adhere | attach with an adhesive agent (not shown).

  Although not shown, the frame body 216 may be bonded to the metal layer 217 formed on the main surface of the surface reflection layer 111.

  In addition, the light guiding efficiency can be improved by making the shape of the frame body 116 a bowl with a bottom or a parabolic antenna.

  FIG. 3C is a cross-sectional view of another embodiment of the light emitting element mounting wiring board of the present invention.

  The light emitting element mounting wiring board 313 of the present invention is mounted on an insulating base 303 formed by laminating insulating layers 311a to 311f made of a light reflector and one main surface 303a of the insulating layers 311d to 311f. In order to connect the connection terminal 305 serving as a terminal for connecting to the light emitting element, the external electrode terminal 307 formed on the other main surface 303b of the insulating base 303, and the connection terminal 305 and the external electrode terminal 307, And a through conductor 309 formed through the insulating layers 311d to 311f.

  The insulating substrate 303 may be a laminated body as shown in FIG. 3C or a bulk body.

  A cavity is formed by the insulating layers 311a to 311c, and a light emitting element mounting portion 315 on which the light emitting element is mounted is disposed on the main surface 303a of the insulating layers 311d to 311f.

  That is, the emitted light of the light emitting element mounted on the light emitting element mounting portion 315 is reflected by the insulating base 303 made of a light reflector, and not only the light directly emitted by the light emitting element but also the insulating base 303 made of a light reflector. Even the reflected light can be guided in an arbitrary direction, so that stronger light can be supplied and the luminous efficiency can be remarkably increased.

  Further, since the insulating layer base 303 made of a light reflector can be baked at a low temperature of 1000 ° C. or lower, the connection terminal 305, the external electrode terminal 307, and the through conductor 309 have a low melting point such as gold, silver, or copper. Simultaneous firing with metals having low resistance is possible, and these low resistance metals can be used as wiring materials. Therefore, power loss can be reduced as compared with the case where an aluminum nitride sintered body or alumina sintered body using a wiring material having high resistance such as W or Mo is used as an insulating base.

  Furthermore, when silver is used as the connection terminal 105, the reflectance of the wiring layer itself is high, so that a higher reflectance can be obtained for the light emitting element mounting wiring substrate 313 as a whole. On the other hand, since silver is expensive, high-reflection is achieved by using inexpensive copper for the connection terminal 305 and the external electrode terminal 307 and applying silver plating or gold plating on the connection terminal 305 and the external electrode terminal 307. It is possible to get a rate. On the other hand, when gold is used for the connection terminal 305 and the external electrode terminal 307, the oxidation resistance is most excellent. Therefore, even when used for a long period of time, the wiring board for mounting a light-emitting element having very excellent reliability without deterioration in characteristics. 313 can be obtained.

  3C shows the light emitting element mounting wiring substrate 313 having a cavity formed around the light emitting element mounting portion 315. However, as shown in FIG. 3A, the light emitting element mounting wiring substrate is flat. You may make it.

  FIG. 4A is a cross-sectional view of an embodiment of the light emitting device of the present invention.

  The light emitting device 127 of the present invention is mounted by adhering an LED chip as a light emitting element 121 with an adhesive 129 on the light emitting element mounting portion 115 of the light emitting element mounting wiring substrate 113 of the present invention shown in FIG. The LED chip 121 and the connection terminal 105 are electrically connected by a bonding wire 123.

  According to the light-emitting device 127 of the present invention, by supplying power to the light-emitting element 121, the light emitted from the light-emitting element 121 can be reflected by the light reflector 111 having a high reflectivity and guided in an arbitrary direction. Thus, a highly efficient light-emitting device 127 is obtained.

  In addition, when a material having high thermal conductivity is used for the insulating base 103, heat generated from the light emitting element 121 can be quickly released, and luminance reduction due to heat can be suppressed.

  Further, although the light emitting element 121 is covered with the molding material 131, it may be sealed using a lid (not shown) without using the molding material 131, and the molding material 131 and the lid are used. And may be used in combination. It is desirable to use a translucent material such as glass for the lid.

  Furthermore, a phosphor (not shown) for converting the wavelength of light emitted from the light emitting element 121 may be added to the molding material 131.

A yellow or blue LED chip or the like is preferably used as the light-emitting element 121, and can be converted into white light by selecting a phosphor that performs appropriate wavelength conversion. In the light emitting device 127 of the present invention, since the light reflector 111 has a high reflectance in the visible light region, the characteristics can be utilized most effectively particularly when used as a light emitting device that emits white light. However, even when used as a red, blue, or green light emitting device, it is possible to exhibit high luminous efficiency.

  In the example shown in FIG. 4A, the light-emitting element 121 is fixed to the light reflector 111 and the light-emitting body wiring substrate 103 with an adhesive 129, and power is supplied by the wire bond 123. The connection form with the wiring board 103 may be flip-chip connection.

  Further, for example, as shown in FIG. 4B, an LED chip is used as the light emitting element 121 on the light emitting element mounting portion 115 of the light emitting element wiring substrate 113 on which the frame body 116 shown in FIG. 3B is formed. The LED chip 121 and the connection terminal 105 may be electrically connected by a bonding wire 123 and mounted by bonding with an adhesive 129.

  In the light emitting device 127 on which the frame body 116 is mounted, the light emitting element 121 can be easily protected by housing the light emitting element 121 inside the frame body 116.

  Furthermore, as shown in FIG. 4C, an LED chip is mounted as a light emitting element 321 with an adhesive 329 on the light emitting element mounting portion 315 of the light emitting element wiring board 313 shown in FIG. In addition, the LED chip 321 and the connection terminal 305 may be electrically connected by the bonding wire 323.

Example 1
A crystallized glass powder having an average particle size of 2.0 μm having the composition shown in Table 1 and a filler having the composition and particle size shown in Table 2 are prepared and weighed according to the composition of Table 2, and an organic binder and a plasticizer are prepared. And the solvent was mixed and the slurry was produced, and the obtained slurry was shape | molded by the doctor blade method.

  The obtained molded body was laminated by a thermocompression bonding method so as to have a thickness of 2 mm, treated with a deorganic binder by heat treatment at 500 ° C. for 2 hours in the atmosphere, and then at 900 ° C. for 1 hour in the air atmosphere. The glass ceramic which is a light reflector was obtained by baking.

About this glass ceramic, a cross section is mirror-polished, a secondary electron image and a backscattered electron image are photographed using a scanning microscope (SEM), and a short particle of a cross section within a range of 100 μm ² using an image analyzer. Diameter, major axis and area were measured. For particles having an aspect ratio of major axis / minor axis and an aspect ratio of 3 or more, the minor axis is calculated as the particle diameter in the cross section. For particles having an aspect ratio of less than 3, a circle having the same area as the area is calculated. The diameter was calculated as the particle diameter in the cross section.

  From the results, the occupied area of the particle group having a particle diameter of 0.3 to 1.0 μm in the cross section was calculated, and the ratio of the occupied area of the particle group in the measurement area is shown in Table 3. Further, the area occupied by particles having an aspect ratio of 3 or more in the particle group was calculated, and the ratio of the area occupied by particles having an aspect ratio of 3 or more in the area occupied by the particle group is shown in Table 3. Indicated.

  The crystal phase of the glass ceramic was identified by measuring the diffraction pattern by X-ray diffraction measurement. Furthermore, the crystallinity was calculated using the Rietveld method. The results are shown in Table 3.

  Further, the reflectance was measured every 10 nm over the entire visible light region having a wavelength of 400 nm to 700 nm by emission spectroscopy, and the values at the wavelength with the lowest reflectance are shown in Table 3.

  In addition, as a comparative sample, a ceramic filler produced by firing only glass G7, which is a non-crystallized glass having the composition shown in Table 1, and a glass sintered body and aluminum nitride sintered containing no crystal phase precipitated by firing A sample was also prepared for the body, and the same evaluation was performed.

Specimen No. Nos. 4 to 17 indicate that the lowest reflectance in the visible light region is 75% or more, that is, a high reflectance of 75% or more over the entire visible light region. In particular the area occupied by the particle aspect ratio is 3 or more is 20% or more specimen No. Nos. 7 to 14 show a high reflectance of 78% or more at the lowest reflectance in the visible light region. Sample No. Reference numerals 9 and 16 are reference examples.

  On the other hand, since there is neither a ceramic filler nor a crystal phase that precipitates upon firing, sample no. No. 1 has a low reflectance. In addition, sample Nos. Made of an aluminum nitride sintered body outside the scope of the present invention. 2 and sample No. 2 using a crystallized glass having a high degree of crystallinity outside the scope of the present invention. In No. 3, although the crystallinity was high, the diameter of the precipitated particles was large, and the amount of fine particles of 0.3 to 1.0 μm deposited was small, so that the reflectance was low.

Example 2
Sample No. within the scope of the present invention. A green sheet having a thickness of 300 μm was formed in the same manner as in Example 1 using 11 light reflector material H. The obtained green sheet is punched to form through-holes, filled with a conductive paste which is copper as a main component and becomes a through-conductor 309 after firing, and a necessary wiring pattern is formed on the green sheet by screen printing. On the front and back surfaces, a wiring layer was formed using a conductive paste containing copper as a main component, and processed green sheets to be insulating layers 311d to 311f were produced. A part of the wiring layer formed on the insulating layer 311 d serves as the connection terminal 305, and a part of the wiring layer formed on the insulating layer 311 f serves as the external electrode terminal 307.

  Separately from this, through holes for forming cavities by punching were similarly formed in the obtained green sheet by punching to produce processed green sheets to be the insulating layers 311a to 311c.

The obtained processed green sheets were aligned and laminated by a thermocompression bonding method to obtain a laminate having a cavity structure.

  The obtained laminate is subjected to a deorganic binder treatment at 700 ° C. in a steam-containing nitrogen atmosphere, and then fired in a steam-containing nitrogen atmosphere at 900 ° C. for 1 hour. A light emitting device having a glass ceramic body as an insulating base, a wiring layer mainly composed of low-resistance copper, the insulating layers 311a to 311c having a thickness of 0.6 mm, and the insulating layers 311d to 311f having a thickness of 0.6 mm An element mounting wiring board 313 was obtained.

  Further, after Ni—Au plating was performed on the external electrode terminal 307 and the connection terminal 305, silver plating was further performed.

  The silver LED plated epoxy resin is used as the adhesive 329 on the light emitting element mounting wiring board 313, the yellow LED chip is used as the light emitting element 321, and the yellow LED chip is positioned on the light emitting element mounting wiring board 313. The LED chip was mounted on the wiring board 313 for light emitting element mounting by setting together and hardening | curing an epoxy resin by heat-processing.

  Subsequently, the connection terminal 305 and the light emitting element 321 are electrically connected by a bonding wire 323 using an Au wire, and a phosphor that converts yellow light into white light is filled thereon, and the LED emits white light. A light emitting device 327 which is a device was obtained.

  Since the obtained white LED device uses a low-resistance metal for the wiring layer, the power loss is small, and the white LED device emits good white light because it has a high reflectance over the entire visible light region.

DESCRIPTION OF SYMBOLS 1, 11 ... Glass ceramics 3, 13 ... Glass 5, 7, 15, 17 ... Ceramic particle 19 ... Anisotropic ceramic particle 101a-101c ... Insulating layer 311a-f ... Insulating layer 103, 303 ... Insulating substrate 105, 305 ... Connection terminal 107, 307 ... External electrode terminal 109, 309 ... Through conductor 111 ... Light reflector 113, 213 313: Light emitting element mounting wiring board 115, 315: Light emitting element mounting portion 121, 221, 321 ... Light emitting element 123, 223, 323 ... Bonding wire 127, 227, 327 ... Light emission apparatus

Claims (8)

It made of glass ceramic containing a glass and ceramic particles, along with containing an average particle diameter 1.3μm or more of the alumina particles in a cross section of the glass ceramic particle size of said ceramic particles is in 0.3~1.0μm An area occupied by a certain particle group is 10 to 70% of the cross section.   The ceramic particles are at least one selected from the group consisting of alumina, zirconia, serdian, slusonite, anorthite, diopsite, forsterite, enstatite, garnite, spinel, willemite, cordierite, mullite, quartz, and solid solutions thereof. The light reflector according to claim 1, comprising a seed. The light reflector according to claim 1, wherein the particle group is at least one of zirconia, garnite, and spinel. The light reflector according to any one of claims 1 to 3, wherein, of the occupied area of the particle group, the occupied area of particles having an aspect ratio of 3 or more is 20% or more. Light reflector according to any one of claims 1 to 4, crystallinity of the glass ceramic is equal to or less than 50%. Light reflector according to any one of claims 1 to 5, characterized in that substantially no contain Tei transition metal elements.   A light emitting element mounting wiring board in which a wiring layer and a light emitting element mounting portion on which a light emitting element is mounted are provided on a main surface of an insulating substrate, and the light emitting element mounting portion is any one of claims 1 to 6. A wiring board for mounting a light emitting element, characterized by comprising a light reflector.   8. A light emitting device comprising a light emitting element mounted on the light emitting element mounting portion of the light emitting element mounting wiring board according to claim 7.

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